Magic Angle Spinning NMR Reveals Sequence-Dependent Structural...
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Magic Angle Spinning NMR Reveals Sequence-Dependent Structural Plasticity, Dynamics, and the Spacer Peptide 1 Conformation in Magic Angle Spinning NMR Reveals Sequence-Dependent...
In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of...
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In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of Supercritical CO2 Incorporation in Smectite-Natural Organic In Situ 13C and 23Na Magic Angle Spinning NMR...
[superscript 15]N-[superscript 15]N Proton Assisted Recoupling in Magic Angle Spinning NMR
Lewandowski, Jozef R.
We describe a new magic angle spinning (MAS) NMR experiment for obtaining [superscript 15]N?[superscript 15]N correlation spectra. The approach yields direct information about the secondary and tertiary structure of proteins, ...
Devices and process for high-pressure magic angle spinning nuclear magnetic resonance
Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi
2014-04-08T23:59:59.000Z
A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.
Advanced slow-magic angle spinning probe for magnetic resonance imaging and spectroscopy
Wind, Robert A.; Hu, Jian Zhi; Minard, Kevin R.; Rommereim, Donald N.
2006-01-24T23:59:59.000Z
The present invention relates to a probe and processes useful for magnetic resonance imaging and spectroscopy instruments. More particularly, the invention relates to a MR probe and processes for obtaining resolution enhancements of fluid objects, including live specimens, using an ultra-slow (magic angle) spinning (MAS) of the specimen combined with a modified phase-corrected magic angle turning (PHORMAT) pulse sequence. Proton NMR spectra were measured of the torso and the top part of the belly of a female BALBc mouse in a 2T field, while spinning the animal at a speed of 1.5 Hz. Results show that even in this relatively low field with PHORMAT, an isotropic spectrum is obtained with line widths that are a factor 4.6 smaller than those obtained in a stationary mouse. Resolution of ^{1}H NMR metabolite spectra are thus significantly enhanced. Results indicate that PHORMAT has the potential to significantly increase the utility of ^{1}H NMR spectroscopy for in vivo biochemical, biomedical and/or medical applications involving large-sized biological objects such as mice, rats and even humans within a hospital setting. For small-sized objects, including biological objects, such as excised tissues, organs, live bacterial cells, and biofilms, use of PASS at a spinning rate of 30 Hz and above is preferred.
Frydman, Lucio
Fast radio-frequency amplitude modulation in multiple-quantum magic-angle-spinning nuclear magnetic of this experiment has been the poor efficiency of the radio-frequency pulses used in converting multiple-modulated radio-frequency pulses, and which can yield substantial signal and even resolution enhancements over
Rotor Design for High Pressure Magic Angle Spinning Nuclear Magnetic Resonance
Turcu, Romulus V.F.; Hoyt, David W.; Rosso, Kevin M.; Sears, Jesse A.; Loring, John S.; Felmy, Andrew R.; Hu, Jian Z.
2013-01-01T23:59:59.000Z
High pressure magic angle spinning (MAS) nuclear magnetic resonance (NMR) with a sample spinning rate exceeding 2.1 kHz and pressure greater than 165 bar has never been realized. In this work, a new sample cell design is reported, suitable for constructing cells of different sizes. Using a 7.5 mm high pressure MAS rotor as an example, internal pressure as high as 200 bar at a sample spinning rate of 6 kHz is achieved. The new high pressure MAS rotor is re-usable and compatible with most commercial NMR set-ups, exhibiting low 1H and 13C NMR background and offering maximal NMR sensitivity. As an example of its many possible applications, this new capability is applied to determine reaction products associated with the carbonation reaction of a natural mineral, antigorite ((Mg,Fe2+)3Si2O5(OH)4), in contact with liquid water in water-saturated supercritical CO2 (scCO2) at 150 bar and 50 deg C. This mineral is relevant to the deep geologic disposal of CO2, but its iron content results in too many sample spinning sidebands at low spinning rate. Hence, this chemical system is a good case study to demonstrate the utility of the higher sample spinning rates that can be achieved by our new rotor design. We expect this new capability will be useful for exploring solid-state, including interfacial, chemistry at new levels of high-pressure in a wide variety of fields.
Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)] [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)
2014-05-14T23:59:59.000Z
We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.
Spinning angle optical calibration apparatus
Beer, Stephen K. (Morgantown, WV); Pratt, II, Harold R. (Morgantown, WV)
1991-01-01T23:59:59.000Z
An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.
Proton chemical shift anisotropy measurements of hydrogen-bonded functional groups by fast magic) spectroscopy is one of the most suitable tools for studying hydrogen bonding phenomena. Proton NMR spectroscopy theoretically4 and experimentally5 that the isotropic chemical shifts of hydroxyl or amide protons depend
Hou, Guangjin, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu; Lu, Xingyu, E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Vega, Alexander J., E-mail: luxingyu@udel.edu, E-mail: lexvega@comcast.net; Polenova, Tatyana, E-mail: hou@udel.edu, E-mail: tpolenov@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, Pennsylvania 15261 (United States)
2014-09-14T23:59:59.000Z
We report a Phase-Alternating R-Symmetry (PARS) dipolar recoupling scheme for accurate measurement of heteronuclear {sup 1}H-X (X = {sup 13}C, {sup 15}N, {sup 31}P, etc.) dipolar couplings in MAS NMR experiments. It is an improvement of conventional C- and R-symmetry type DIPSHIFT experiments where, in addition to the dipolar interaction, the {sup 1}H CSA interaction persists and thereby introduces considerable errors in the dipolar measurements. In PARS, phase-shifted RN symmetry pulse blocks applied on the {sup 1}H spins combined with ? pulses applied on the X spins at the end of each RN block efficiently suppress the effect from {sup 1}H chemical shift anisotropy, while keeping the {sup 1}H-X dipolar couplings intact. Another advantage over conventional DIPSHIFT experiments, which require the signal to be detected in the form of a reduced-intensity Hahn echo, is that the series of ? pulses refocuses the X chemical shift and avoids the necessity of echo formation. PARS permits determination of accurate dipolar couplings in a single experiment; it is suitable for a wide range of MAS conditions including both slow and fast MAS frequencies; and it assures dipolar truncation from the remote protons. The performance of PARS is tested on two model systems, [{sup 15}N]-N-acetyl-valine and [U-{sup 13}C,{sup 15}N]-N-formyl-Met-Leu-Phe tripeptide. The application of PARS for site-resolved measurement of accurate {sup 1}H-{sup 15}N dipolar couplings in the context of 3D experiments is presented on U-{sup 13}C,{sup 15}N-enriched dynein light chain protein LC8.
Methods for magnetic resonance analysis using magic angle technique
Hu, Jian Zhi (Richland, WA); Wind, Robert A. (Kennewick, WA); Minard, Kevin R. (Kennewick, WA); Majors, Paul D. (Kennewick, WA)
2011-11-22T23:59:59.000Z
Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.
Method for high resolution magnetic resonance analysis using magic angle technique
Wind, Robert A.; Hu, Jian Zhi
2003-11-25T23:59:59.000Z
A method of performing a magnetic resonance analysis of a biological object that includes placing the biological object in a main magnetic field and in a radio frequency field, the main magnetic field having a static field direction; rotating the biological object at a rotational frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. According to another embodiment, the radio frequency is pulsed to provide a sequence capable of producing a spectrum that is substantially free of spinning sideband peaks.
High Temperature, Large Sample Volume, Constant Flow Magic Angle...
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sample spinning rate of 3.5 kHz, 1 H and 13 C 90-degree pulse width of 8 s, constant flow control at 1.0 atmospheric pressure, and temperature control up to 250 C. This...
Method for high resolution magnetic resonance analysis using magic angle technique
Wind, Robert A.; Hu, Jian Zhi
2003-12-30T23:59:59.000Z
A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.
Method for high resolution magnetic resonance analysis using magic angle technique
Wind, Robert A.; Hu, Jian Zhi
2004-12-28T23:59:59.000Z
A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.
Hu, Jian Zhi (Richland, WA); Sears, Jr., Jesse A. (Kennewick, WA); Hoyt, David W. (Richland, WA); Wind, Robert A. (Kennewick, WA)
2009-05-19T23:59:59.000Z
Described are a "Discrete Magic Angle Turning" (DMAT) system, devices, and processes that combine advantages of both magic angle turning (MAT) and magic angle hopping (MAH) suitable, e.g., for in situ magnetic resonance spectroscopy and/or imaging. In an exemplary system, device, and process, samples are rotated in a clockwise direction followed by an anticlockwise direction of exactly the same amount. Rotation proceeds through an angle that is typically greater than about 240 degrees but less than or equal to about 360 degrees at constant speed for a time applicable to the evolution dimension. Back and forth rotation can be synchronized and repeated with a special radio frequency (RF) pulse sequence to produce an isotropic-anisotropic shift 2D correlation spectrum. The design permits tubes to be inserted into the sample container without introducing plumbing interferences, further allowing control over such conditions as temperature, pressure, flow conditions, and feed compositions, thus permitting true in-situ investigations to be carried out.
HYDROGEN AND DEUTERIUM NMR OF SOLIDS BY MAGIC ANGLE SPINNING
Eckman, R.R.
2010-01-01T23:59:59.000Z
Reduced H~S for Hydrogen ••..•. Observation ofb. Dilution of Hydrogen: Appraoch to High Resolution ProtonMolecular Research ,Division HYDROGEN AND DEUTERIUM NMR OF
High-pressure Magic Angle Spinning Nuclear Magnetic Resonance...
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advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other plastic sealing mechanisms...
A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance...
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the surface functional groups of HPAmeso-silicalite-1 under the condition of in-situ drying . We also show that the reaction dynamics of 2-butanol dehydration using HPA...
Tao, X. D.; Feng, Z.; Miao, B. F.; Sun, L.; You, B.; Wu, D.; Du, J.; Zhang, W.; Ding, H. F., E-mail: hfding@nju.edu.cn [Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)
2014-05-07T23:59:59.000Z
We present the experimental study of the spin Hall angle (SHA) and spin diffusion length of Pd with the spin pumping and microwave photoresistance effects. The Py/Pd bilayer stripes are excited with an out-of-plane microwave magnetic field. The pure spin current is thus pumped and transforms into charge current via the inverse spin Hall effect (ISHE) in Pd layer, yielding an ISHE voltage. The ISHE voltage can be distinguished from the unwanted signal caused by the anisotropic magnetoresistance according to their different symmetries. Together with Pd thickness dependent measurements of in and out-of-plane precessing angles and effective spin mixing conductance, the SHA and spin-diffusion length of Pd are quantified as 0.0056?±?0.0007 and 7.3?±?0.7?nm, respectively.
High-temperature in situ magic-angle spinning NMR studies of chemical reactions on catalysts
Oliver, F. Gregory
1992-01-01T23:59:59.000Z
temperature jump to 623 K. Important differences observed in this study relative to previous investigations at lower temperatures include well-resolved signals for adsorbed versus exogenous (gas phase) methanol and dimethyl ether, and a higher yield... described in the text. 29 Expanded view of the first three spectra in Figure 7 showing the regions containing methanol and dimethyl ether. In the high- temperature spectra two peaks are present for both species; gas phase (48. 0 ppm) and adsorbed (53. 1...
Eddy, Matthew T.
The power of nuclear magnetic resonance spectroscopy derives from its site-specific access to chemical, structural and dynamic information. However, the corresponding multiplicity of interactions can be difficult to tease ...
angle spinning proton: Topics by E-print Network
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hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is...
angle field spinning: Topics by E-print Network
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and Glitches Astrophysics (arXiv) Summary: In the core of a canonical spinning magnetized neutron star(NS) a nearly uniform superfluid neutron vortex-array interacts strongly with...
angle spinning dynamic: Topics by E-print Network
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Quantization of this model is briefly discussed. S. A. Pol'shin 2011-10-24 87 Dynamics of artificial spin ice: a continuous honeycomb network MIT - DSpace Summary: We model the...
angle spinning nuclear: Topics by E-print Network
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spinning nuclear First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Cryogenic sample exchange NMR probe...
Comparative study of high-spin isomers in semi-magic $Z$=50 isotopic and $N$=82 isotonic chains
Bhoomika Maheshwari; Ashok Kumar Jain; P. C. Srivastava
2014-08-08T23:59:59.000Z
A comparative study of high spin nuclear isomers observed in the semi-magic $Z$=50 isotopic and $N$=82 isotonic chains has been carried out. The ${11/2}^-$, ${10}^+$ and ${27/2}^-$ isomers, which occur commonly in both the chains, display nearly identical systematics in excitation energy and half-life. An energy gap of ${\\sim 4}$ MeV between the ${0^+}$ ground states and ${10}^+$ isomers and, the ${11/2}^-$ and ${27/2}^-$ isomers exists before the mid-shell, which becomes a constant ${\\sim 3}$ MeV after the mid-shell region. The large scale shell model calculations are able to reproduce the observed energy systematics for both the chains reasonably well. The shell model occupancies and the basic seniority rules have been used to fix the seniority quantum number. The seniority of all the isomeric states as well as those involved in the decay from$/$to the isomers have been assigned and the alignment properties are also discussed. The seniorities of the ${10}^+$ and ${27/2}^-$ isomeric states before the mid-shell are higher, which become lower after the mid-shell, due to the dominant role played by the $h_{11/2}$ orbital. The empirical systematics and the calculated results suggest that the change in the energy gap around the mid-shell, may be interpreted in terms of a change in the seniority of the isomeric states. However, the seniority of the ${11/2}^-$ state remains conserved throughout both the chains. The systematics of the half-lives in both the chains have been understood on the basis of seniority and decay modes. Predictions for new isomers have also been made based on these systematics.
"Magic Angle Precession" Bernd Binder
Binder, Bernd
by geometric phases, which are induced by high- speed relativistic rotations and are relevant to propulsion, quark, confinement, heavy nuclei, Sommerfeld, fine structure, propulsion, SO(3), nonlinear, chaotic maps in the vicinity of a magnetic monopole or singularity (Dirac, 1931) that could be located on the tip
Proton Assisted Recoupling at High Spinning Frequencies
Struppe, Jochem
We demonstrate the successful application of [superscript 13]C?[superscript 13]C proton assisted recoupling (PAR) on [U?[superscript 13]C,[superscript 15]N] N-f-MLF-OH and [U?13C,15N] protein GB1 at high magic angle spinning ...
Eddy, Matthew T. (Matthew Thomas)
2012-01-01T23:59:59.000Z
Membrane proteins mediate critical functions in biological systems and are important drug targets for a number of diseases. Determining the three-dimensional structure and function of membrane proteins under physologically ...
Andreas, Loren B
2014-01-01T23:59:59.000Z
Determination of the 3D structure of membrane proteins is a frontier that is rapidly being explored due to the importance of membrane proteins in regulating cellular processes and because they are the target of many drugs. ...
Pan, Z.-H.
We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi[subscript 2]Se[subscript 3], a model TI. By tuning the photon ...
Dey, Rik, E-mail: rikdey@utexas.edu; Pramanik, Tanmoy; Roy, Anupam; Rai, Amritesh; Guchhait, Samaresh; Sonde, Sushant; Movva, Hema C. P.; Register, Leonard F.; Banerjee, Sanjay K. [Microelectronics Research Center, University of Texas at Austin, Austin, Texas 78758 (United States); Colombo, Luigi [Texas Instruments, Dallas, Texas 75243 (United States)
2014-06-02T23:59:59.000Z
We have studied angle dependent magnetoresistance of Bi{sub 2}Te{sub 3} thin film with field up to 9?T over 2–20?K temperatures. The perpendicular field magnetoresistance has been explained by the Hikami-Larkin-Nagaoka theory alone in a system with strong spin-orbit coupling, from which we have estimated the mean free path, the phase coherence length, and the spin-orbit relaxation time. We have obtained the out-of-plane spin-orbit relaxation time to be small and the in-plane spin-orbit relaxation time to be comparable to the momentum relaxation time. The estimation of these charge and spin transport parameters are useful for spintronics applications. For parallel field magnetoresistance, we have confirmed the presence of Zeeman effect which is otherwise suppressed in perpendicular field magnetoresistance due to strong spin-orbit coupling. The parallel field data have been explained using both the contributions from the Maekawa-Fukuyama localization theory for non-interacting electrons and Lee-Ramakrishnan theory of electron-electron interactions. The estimated Zeeman g-factor and the strength of Coulomb screening parameter agree well with the theory. Finally, the anisotropy in magnetoresistance with respect to angle has been described by the Hikami-Larkin-Nagaoka theory. This anisotropy can be used in anisotropic magnetic sensor applications.
Bai, Lihui; Hyde, P.; Hu, C.-M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2 (Canada)] [Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2 (Canada); Feng, Z.; Ding, H. F. [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)] [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)
2013-06-17T23:59:59.000Z
A pure spin current driven by spin pumping is converted to a DC voltage and detected electrically in a Py/Pt bilayer sample. This DC voltage mixes with a DC voltage produced through spin rectification. The ferromagnetic resonance line shape strongly depends on the microwave magnetic h field distribution. We have systematically studied the line shapes by changing the external magnetic field orientation in plane of a Pt/Py bilayer. A method is demonstrated which allows us to calculate the microwave h field vector distribution, and distinguish spin pumping from spin rectification.
Ganguly, A.; Haldar, A.; Sinha, J.; Barman, A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India); Rowan-Robinson, R. M.; Jaiswal, S.; Hindmarch, A. T.; Atkinson, D. A., E-mail: abarman@bose.res.in, E-mail: del.atkinson@durham.ac.uk [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
2014-09-15T23:59:59.000Z
The effect of spin torque from the spin Hall effect in Pt/Ni{sub 81}Fe{sub 19} rectangular bilayer film was investigated using time-resolved magneto-optical Kerr microscopy. Current flow through the stack resulted in a linear variation of effective damping up to ±7%, attributed to spin current injection from the Pt into the Ni{sub 81}Fe{sub 19}. The spin Hall angle of Pt was estimated as 0.11?±?0.03. The modulation of the damping depended on the angle between the current and the bias magnetic field. These results demonstrate the importance of optical detection of precessional magnetization dynamics for studying spin transfer torque due to spin Hall effect.
Nuruzzaman, nfn [Thomas Jefferson National Accelerator Facility and Hampton University
2014-12-01T23:59:59.000Z
The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppb correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam modulation system has also proven valuable for tracking changes in the beamline optics, such as dispersion at the target.
Pan, Z.H.; Vescovo, E.; Fedorov, A.V.; Gardner, D.; Lee, Y.S.; Chu, S.; Gu, G.D.; Valla, T.
2011-06-22T23:59:59.000Z
We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi{sub 2}Se{sub 3}, a model TI. By tuning the photon energy, we found that the topological surface state is well separated from the bulk states in the vicinity of k{sub z} = Z plane of the bulk Brillouin zone. The spin-resolved measurements in that region indicate a very high degree of spin polarization of the surface state, {approx}0.75, much higher than previously reported. Our results demonstrate that the topological surface state on Bi{sub 2}Se{sub 3} is highly spin polarized and that the dominant factors limiting the polarization are mainly extrinsic.
Hu, Jian Zhi; Kwak, Ja Hun; Yang, Zhenguo; Osborn, William; Markmaitree, Tippawan; Shaw, Leonard D.
2008-07-15T23:59:59.000Z
Abstract The significantly enhanced spectral resolution in the 6Li MAS NMR spectra of Li-N-H systems at ultra-high field of 21.1 tesla is exploited, for the first time, to study the detailed electronic and chemical environmental changes associated with mechanical activation of Li-N-H system using high energy balling milling. Complementary to ultra-high field studies, the hydrogen discharge dynamics are investigated using variable temperature in situ 1H MAS NMR at 7.05 tesla field. The significantly enhanced spectral resolution using ultra-high filed of 21.1 tesla was demonstrated along with several major findings related to mechanical activation, including the upfield shift of the resonances in 6Li MAS spectra induced by ball milling, more efficient mechanical activation with ball milling at liquid nitrogen temperature than with ball milling at room temperature, and greatly enhanced hydrogen discharge exhibited by the liquid nitrogen ball milled samples.
Qutrit Magic State Distillation
Anwar, Hussain; Browne, Dan E
2012-01-01T23:59:59.000Z
Magic state distillation (MSD) is a purification protocol that plays a central role in fault tolerant quantum computation. Repeated iteration of the steps of a MSD protocol, generates pure single non-stabilizer states, or magic states, from multiple copies of a mixed resource state using stabilizer operations only. Thus mixed resource states promote the stabilizer operations to full universality. Magic state distillation was introduced for qubit-based quantum computation, but little has been known concerning MSD in higher dimensional qudit-based computation. Here, we describe a general approach for studying MSD in higher dimensions. We use it to investigate the features of a qutrit MSD protocol based on the 5-qutrit stabilizer code. We show that this protocol distills non-stabilizer magic states, and identify two types of states, that are attractors of this iteration map. Finally, we show how these states may be converted, via stabilizer circuits alone, into a state suitable for state injected implementation ...
Magic Tutorial #1: Getting Started John Ousterhout
Martin, Alain
Magic Tutorial #1: Getting Started John Ousterhout (updated by others, too) Computer Science ############################################################# Magic Tutorial #1: Getting Started Magic Tutorial #2: Basic Painting and Selection Magic Tutorial #3 Division Electrical Engineering and Computer Sciences University of California Berkeley, CA 94720
Magic Tutorial #1: Getting Started John Ousterhout
Baas, Bevan
Magic Tutorial #1: Getting Started John Ousterhout Computer Science Division Electrical Engineering and Computer Sciences University of California Berkeley, CA 94720 (Updated by others, too.) This tutorial #1: Getting Started Magic Tutorial #1: Getting Started Magic Tutorial #2: Basic Painting
V. G. Baryshevsky; A. A. Gurinovich
2005-06-14T23:59:59.000Z
In the present paper the equations for the spin evolution of a particle in a storage ring are analyzed considering contributions from the tensor electric and magnetic polarizabilities of the particle. Study of spin rotation and birefringence effect for a particle in a high energy storage ring provides for measurement as the real part of the coherent elastic zero-angle scattering amplitude as well as tensor electric and magnetic polarizabilities. We proposed the method for measurement the real part of the elastic coherent zero-angle scattering amplitude of particles and nuclei in a storage ring by the paramagnetic resonance in the periodical in time nuclear pseudoelectric and pseudomagnetic fields.
M. S. Safronova; Z. Zuhrianda; U. I. Safronova; Charles W. Clark
2015-07-23T23:59:59.000Z
We predict a sequence of magic-zero wavelengths for the Sr excited $5s5p~ ^3P_0$ state, and provide a general roadmap for extracting transition matrix elements using precise frequency measurements. We demonstrate that such measurements can serve as a best global benchmark of the spectroscopic accuracy that is required for the development of high-precision predictive methods. These magic-zero wavelengths are also needed for state-selective atom manipulation for implementation of quantum logic operations. We also identify five magic wavelengths of the $5s^2\\ ^1S_0 - 5s5p\\ ^3P_0$ Sr clock transition between 350 nm and 500 nm which can also serve as precision benchmarks.
Hsieh, David
We report high-resolution spin-resolved photoemission spectroscopy (spin-ARPES) measurements on the parent compound Sb of the recently discovered three-dimensional topological insulator Bi1?xSbx (Hsieh et al 2008 Nature ...
Nonlinear and magic ponderomotive spectroscopy
Moore, Kaitlin
2015-01-01T23:59:59.000Z
In ponderomotive spectroscopy an amplitude-modulated optical standing wave is employed to probe Rydberg-atom transitions, utilizing a ponderomotive rather than a dipole-field interaction. Here, we engage nonlinearities in the modulation to drive dipole-forbidden transitions up to the fifth order. We reach transition frequencies approaching the sub-THz regime. We also demonstrate magic-wavelength conditions, which result in symmetric spectral lines with a Fourier-limited feature at the line center. Applicability to precision measurement is discussed.
Vladimir Baryshevsky
2002-12-09T23:59:59.000Z
New experiment arrangement to study spin rotation and oscillation of particles of gas target through which beam of high energy particles passes is discussed. Such experiment arrangement make it realizable for storage ring and allows to study zero-angle scattering amplitude at highest possible energies. Life-time of particle beam in storage ring can reach several hours and even days. Life-time of particle in gas target (gas trap) is long too. Particles circulate in storage ring with frequency $\
Waidyawansa, Dinayadura Buddhini [OHIO U.
2013-08-01T23:59:59.000Z
The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least three orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.
Magic Words: How Language Augments Human Computation
Clark, Andy
1998-01-01T23:59:59.000Z
Of course, words aren’t magic. Neither are sextants, compasses, maps, slide rules and all the other paraphenelia which have accreted around the basic biological brains of homo sapiens. In the case of these other tools and ...
Distilling one-qubit magic states into Toffoli states
Bryan Eastin
2013-02-21T23:59:59.000Z
For certain quantum architectures and algorithms, most of the required resources are consumed during the distillation of one-qubit magic states for use in performing Toffoli gates. I show that the overhead for magic-state distillation can be reduced by merging distillation with the implementation of Toffoli gates. The resulting routine distills 8 one-qubit magic states directly to a Toffoli state, which can be used without further magic to perform a Toffoli gate.
Magic State Distillation and Gate Compilation in Quantum Algorithms for Quantum Chemistry
Colin J. Trout; Kenneth R. Brown
2015-01-29T23:59:59.000Z
Quantum algorithms for quantum chemistry map the dynamics of electrons in a molecule to the dynamics of a coupled spin system. To reach chemical accuracy for interesting molecules, a large number of quantum gates must be applied which implies the need for quantum error correction and fault-tolerant quantum computation. Arbitrary fault-tolerant operations can be constructed from a small, universal set of fault-tolerant operations by gate compilation. Quantum chemistry algorithms are compiled by decomposing the dynamics of the coupled spin-system using a Trotter formula, synthesizing the decomposed dynamics using Clifford operations and single-qubit rotations, and finally approximating the single-qubit rotations by a sequence of fault-tolerant single-qubit gates. Certain fault-tolerant gates rely on the preparation of specific single-qubit states referred to as magic states. As a result, gate compilation and magic state distillation are critical for solving quantum chemistry problems on a quantum computer. We review recent progress that has improved the efficiency of gate compilation and magic state distillation by orders of magnitude.
The Magic and Mysteries of Water
Richmond, Geraldine L.
The Magic and Mysteries of Water Speaker: Prof. Geri Richmond University of Oregon Water is ubiquitous in our lives. Covering more than two thirds of this planet, water surfaces provide a unique role in controlling our climate. In our bodies, water is the `canal of life', transporting and passing
Foston, M.; Katahira, R.; Gjersing, E.; Davis, M. F.; Ragauskas, A. J.
2012-02-15T23:59:59.000Z
The average spatial dimensions between major biopolymers within the plant cell wall can be resolved using a solid-state NMR technique referred to as a {sup 13}C cross-polarization (CP) SELDOM (selectively by destruction of magnetization) with a mixing time delay for spin diffusion. Selective excitation of specific aromatic lignin carbons indicates that lignin is in close proximity to hemicellulose followed by amorphous and finally crystalline cellulose. {sup 13}C spin diffusion time constants (T{sub SD}) were extracted using a two-site spin diffusion theory developed for {sup 13}C nuclei under magic angle spinning (MAS) conditions. These time constants were then used to calculate an average lower-limit spin diffusion length between chemical groups within the plant cell wall. The results on untreated {sup 13}C enriched corn stover stem reveal that the lignin carbons are, on average, located at distances {approx}0.7-2.0 nm from the carbons in hemicellulose and cellulose, whereas the pretreated material had larger separations.
Status of the second phase of the MAGIC telescope
Florian Goebel; for the MAGIC collaboration
2007-09-17T23:59:59.000Z
The MAGIC 17m diameter Cherenkov telescope will be upgraded with a second telescope with advanced photon detectors and ultra fast readout within the year 2007. The sensitivity of MAGIC-II, the two telescope system, will be improved by a factor of 2. In addition the energy threshold will be reduced and the energy and angular resolution will be improved. The design, status and expected performance of MAGIC-II is presented here.
Magic Valley Electric Cooperative- ENERGY STAR Builders Program (Texas)
Broader source: Energy.gov [DOE]
Magic Valley Electric Cooperative's (MVEC) ENERGY STAR Builders Program offers a variety of incentives to builders of energy efficiency homes within MVEC service territory. Incentives are provided...
Magic Valley Electric Cooperative- Residential Energy Efficiency Rebate Program
Broader source: Energy.gov [DOE]
Magic Valley Electric Cooperative's Value Incentive Program (VIP) offers consumers incentives for the installation of new central heat pump systems, dual fuel heating systems, central air...
E-Print Network 3.0 - accelerating electromagnetic magic Sample...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
accelerating electromagnetic magic Page: << < 1 2 3 4 5 > >> 1 Very High Energy Gamma Ray Observations with the MAGIC Summary: Very High Energy Gamma Ray Observations with the...
Liz O'Brien Social Research Group Magical place
and Market Research who organised and facilitated eight of the sixteen discussion groups and contributedLiz O'Brien Social Research Group A sort of Magical place People's experiences of woodlands in northwest and southeast England #12;Liz O'Brien Social Research Group Forest Research 1A Sort of Magical
Los Alamos scientists monitor Santa's magical journey
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is YourAwardspublicexceedsScientists monitor Santa's magical
Contextuality supplies the magic for quantum computation
Mark Howard; Joel J. Wallman; Victor Veitch; Joseph Emerson
2014-10-15T23:59:59.000Z
Quantum computers promise dramatic advantages over their classical counterparts, but the answer to the most basic question "What is the source of the power in quantum computing?" has remained elusive. Here we prove a remarkable equivalence between the onset of contextuality and the possibility of universal quantum computation via magic state distillation. This is a conceptually satisfying link because contextuality provides one of the fundamental characterizations of uniquely quantum phenomena and, moreover, magic state distillation is the leading model for experimentally realizing fault-tolerant quantum computation. Furthermore, this connection suggests a unifying paradigm for the resources of quantum information: the nonlocality of quantum theory is a particular kind of contextuality and nonlocality is already known to be a critical resource for achieving advantages with quantum communication. In addition to clarifying these fundamental issues, this work advances the resource framework for quantum computation, which has a number of practical applications, such as characterizing the efficiency and trade-offs between distinct theoretical and experimental schemes for achieving robust quantum computation and bounding the overhead cost for the classical simulation of quantum algorithms.
MAGIC: Marine ARM GPCI Investigation of Clouds
Lewis, ER; Wiscombe, WJ; Albrecht, BA; Bland, GL; Flagg, CN; Klein, SA; Kollias, P; Mace, G; Reynolds, RM; Schwartz, SE; Siebesma, AP; Teixeira, J; Wood, R; Zhang, M
2012-10-03T23:59:59.000Z
The second Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF2) will be deployed aboard the Horizon Lines cargo container ship merchant vessel (M/V) Spirit for MAGIC, the Marine ARM GPCI1 Investigation of Clouds. The Spirit will traverse the route between Los Angeles, California, and Honolulu, Hawaii, from October 2012 through September 2013 (except for a few months in the middle of this time period when the ship will be in dry dock). During this field campaign, AMF2 will observe and characterize the properties of clouds and precipitation, aerosols, and atmospheric radiation; standard meteorological and oceanographic variables; and atmospheric structure. There will also be two intensive observational periods (IOPs), one in January 2013 and one in July 2013, during which more detailed measurements of the atmospheric structure will be made.
Multilevel distillation of magic states for quantum computing
Cody Jones
2013-03-27T23:59:59.000Z
We develop a procedure for distilling magic states used in universal quantum computing that requires substantially fewer initial resources than prior schemes. Our distillation circuit is based on a family of concatenated quantum codes that possess a transversal Hadamard operation, enabling each of these codes to distill the eigenstate of the Hadamard operator. A crucial result of this design is that low-fidelity magic states can be consumed to purify other high-fidelity magic states to even higher fidelity, which we call "multilevel distillation." When distilling in the asymptotic regime of infidelity $\\epsilon \\rightarrow 0$ for each input magic state, the number of input magic states consumed on average to yield an output state with infidelity $O(\\epsilon^{2^r})$ approaches $2^r+1$, which comes close to saturating the conjectured bound in [Phys. Rev. A 86, 052329]. We show numerically that there exist multilevel protocols such that the average number of magic states consumed to distill from error rate $\\epsilon_{\\mathrm{in}} = 0.01$ to $\\epsilon_{\\mathrm{out}}$ in the range $10^{-5}$ to $10^{-40}$ is about $14\\log_{10}(1/\\epsilon_{\\mathrm{out}}) - 40$; the efficiency of multilevel distillation dominates all other reported protocols when distilling Hadamard magic states from initial infidelity 0.01 to any final infidelity below $10^{-7}$. These methods are an important advance for magic-state distillation circuits in high-performance quantum computing, and they provide insight into the limitations of nearly resource-optimal quantum error correction.
Cacho, Cephise M. [Sincrotrone Trieste, Strada Statale 14, km 163,5 in AREA Science Park, 34012 Basovizza, Trieste (Italy); Photon Science Department, Science and Technology Facilities Council, Daresbury WA4 4AD (United Kingdom); Vlaic, Sergio [Dipartimento di Fisica, Universita di Trieste, via Valerio 2, 34127 Trieste (Italy); Malvestuto, Marco; Ressel, Barbara [Sincrotrone Trieste, Strada Statale 14, km 163,5 in AREA Science Park, 34012 Basovizza, Trieste (Italy); Seddon, Elaine A. [Photon Science Department, Science and Technology Facilities Council, Daresbury WA4 4AD (United Kingdom); Parmigiani, Fulvio [Sincrotrone Trieste, Strada Statale 14, km 163,5 in AREA Science Park, 34012 Basovizza, Trieste (Italy); Dipartimento di Fisica, Universita di Trieste, via Valerio 2, 34127 Trieste (Italy)
2009-04-15T23:59:59.000Z
Here we report the absolute characterization of a spin polarimeter by measuring the Sherman function with high precision. These results have been obtained from the analysis of the spin and angle-resolved photoemission spectra of Au(111) surface states. The measurements have been performed with a 250 kHz repetition rate Ti:sapphire amplified laser system combined with a high energy-, angle-, and spin-resolving time-of-flight electron spectrometer.
Self-consistent description of single-particle levels of magic nuclei
N. V. Gnezdilov; I. N. Borzov; E. E. Saperstein; S. V. Tolokonnikov
2014-04-04T23:59:59.000Z
Single-particle levels of seven magic nuclei are calculated within the Energy Density Functional (EDF) method by Fayans et al. Three versions of the EDF are used, the initial Fayans functional DF3 and its two variations, DF3-a and DF3-b, with different values of spin-orbit parameters. Comparison is made with predictions of the Skyrme-Hartree-Fock method with the HFB-17 functional. For the DF3-a functional, phonon coupling (PC) corrections to single-particle energies are found self-consistently with an approximate account for the tadpole diagram. Account for the PC corrections improves agreement with the data for heavy nuclei, e.g. for 208 Pb. On the other hand, for lighter nuclei, e.g. 40,48 Ca, PC corrections make the agreement a little worse. As estimations show, the main reason is that the approximation we use for the tadpole term is less accurate for the light nuclei.
Ultrafast optical spin echo for electron spins in semiconductors
Susan M. Clark; Kai-Mei C. Fu; Qiang Zhang; Thaddeus D. Ladd; Colin Stanley; Yoshihisa Yamamoto
2009-04-03T23:59:59.000Z
Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time, T2, of a spin system. We report on the experimental implementation of all-optical spin echo to determine the T2 time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an echo signal as the time between pulses is lengthened. Unlike previous spin-echo techniques using microwaves, ultrafast optical pulses allow clean T2 measurements of systems with dephasing times T2* fast in comparison to the timescale for microwave control. This demonstration provides a step toward ultrafast optical dynamic decoupling of spin-based qubits.
The Evolution of Variability in Magic, Divination and Religion: A Multi-level Selection Analysis
Laporte, Catharina
2013-12-02T23:59:59.000Z
for the hypothesis that magical behaviors are pursuits primarily undertaken to achieve personal or kin related needs. In this data set, 78% of magical behaviors target individuals or their immediate kin. Data analysis also highlights various adaptive strategies...
assessing field-scale migration: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
de 6 Assessment of magic angle spinning spectroscopy for studying migration in solid milk chocolate MIT - DSpace Summary: In the confectionery industry, there is...
Bound entanglement in the magic simplex of two--qutrits
Reinhold A. Bertlmann; Philipp Krammer
2008-06-20T23:59:59.000Z
We investigate the entanglement properties of a three--parameter family of states that are part of the magic simplex of two qutrits, which is a simplex of states that are mixtures of maximally entangled two--qutrit Bell states. Using entanglement witnesses we reveal large regions of bound entangled and separable states.
Magic Wavelength for Hydrogen 1S-2S Transition
Kawasaki, Akio
2015-01-01T23:59:59.000Z
The magic wavelength for an optical lattice for hydrogen atoms that cancels the first order AC Stark shift of 1S-2S transition is calculated to be 513 nm. The amount of AC Stark shift $ \\Delta E = -1.19$ kHz/(10kW/cm$^2$) and the slope $d\\Delta E/d \
Deorani, Praveen; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)] [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)
2013-12-02T23:59:59.000Z
From spin pumping measurements in Ta/Py devices for different thicknesses of Ta, we determine the spin Hall angle to be 0.021–0.033 and spin diffusion length to be 8?nm in Ta. We have also studied the effect of changing the properties of non-magnet/ferromagnet interface by adding a Cu interlayer. The experimental results show that the effective spin mixing conductance increases in the presence of Cu interlayer for Ta/Cu/Py devices whereas it decreases in Pt/Cu/Py devices. Our findings allow the tunability of the spin pumping efficiency by adding a thin interlayer at the non-magnet/ferromagnet interface.
M. Zalewski; J. Dobaczewski; W. Satula; T. R. Werner
2008-01-07T23:59:59.000Z
A new strategy of fitting the coupling constants of the nuclear energy density functional is proposed, which shifts attention from ground-state bulk to single-particle properties. The latter are analyzed in terms of the bare single-particle energies and mass, shape, and spin core-polarization effects. Fit of the isoscalar spin-orbit and both isoscalar and isovector tensor coupling constants directly to the f5/2-f7/2 spin-orbit splittings in 40Ca, 56Ni, and 48Ca is proposed as a practical realization of this new programme. It is shown that this fit requires drastic changes in the isoscalar spin-orbit strength and the tensor coupling constants as compared to the commonly accepted values but it considerably and systematically improves basic single-particle properties including spin-orbit splittings and magic-gap energies. Impact of these changes on nuclear binding energies is also discussed.
Photonic spin Hall effect in topological insulators
Zhou, Xinxing; Ling, Xiaohui; Chen, Shizhen; Luo, Hailu; Wen, Shuangchun
2013-01-01T23:59:59.000Z
In this paper we theoretically investigate the photonic spin Hall effect (SHE) of a Gaussian beam reflected from the interface between air and topological insulators (TIs). The photonic SHE is attributed to spin-orbit coupling and manifests itself as in-plane and transverse spin-dependent splitting. We reveal that the spin-orbit coupling effect in TIs can be routed by adjusting the axion angle variations. Unlike the transverse spin-dependent splitting, we find that the in-plane one is sensitive to the axion angle. It is shown that the polarization structure in magneto-optical Kerr effect is significantly altered due to the spin-dependent splitting in photonic SHE. We theoretically propose a weak measurement method to determine the strength of axion coupling by probing the in-plane splitting of photonic SHE.
Qutrit Magic State Distillation Tight in Some Directions
Hillary Dawkins; Mark Howard
2015-04-22T23:59:59.000Z
Magic state distillation is a crucial component in the leading approaches to implementing universal fault tolerant quantum computation, with existing protocols for both qubit and higher dimensional systems. Early work focused on determining the region of distillable states for qubit protocols, yet comparatively little is known about which states can be distilled and with what distillable region for d>2. Here we focus on d=3 and present new four-qutrit distillation schemes that improve upon the known distillable region, and achieve distillation tight to the boundary of undistillable states for some classes of state. As a consequence of recent results, this implies that there is a family of quantum states that enable universality if and only if they exhibit contextuality with respect to stabilizer measurements. We also identify a new routine whose fixed point is a magic state with maximal sum-negativity i.e., it is maximally non-stabilizer in a specific sense.
Magic-state distillation with the four-qubit code
Meier, Adam M; Knill, Emanuel
2012-01-01T23:59:59.000Z
The distillation of magic states is an often-cited technique for enabling universal quantum computing once the error probability for a special subset of gates has been made negligible by other means. We present a routine for magic-state distillation that reduces the required overhead for a range of parameters of practical interest. Each iteration of the routine uses a four-qubit error-detecting code to distill the +1 eigenstate of the Hadamard gate at a cost of ten input states per two improved output states. Use of this routine in combination with the 15-to-1 distillation routine described by Bravyi and Kitaev allows for further improvements in overhead.
Magic-state distillation with the four-qubit code
Adam M. Meier; Bryan Eastin; Emanuel Knill
2012-04-18T23:59:59.000Z
The distillation of magic states is an often-cited technique for enabling universal quantum computing once the error probability for a special subset of gates has been made negligible by other means. We present a routine for magic-state distillation that reduces the required overhead for a range of parameters of practical interest. Each iteration of the routine uses a four-qubit error-detecting code to distill the +1 eigenstate of the Hadamard gate at a cost of ten input states per two improved output states. Use of this routine in combination with the 15-to-1 distillation routine described by Bravyi and Kitaev allows for further improvements in overhead.
On spectroscopic factors of magic and semimagic nuclei
Saperstein, E. E. [Kurchatov Institute, 123182 Moscow (Russian Federation); Gnezdilov, N. V. [Kurchatov Institute, 123182 Moscow, Russia and National Research Nuclear University MEPhI, 115409 Moscow (Russian Federation); Tolokonnikov, S. V. [Kurchatov Institute, 123182 Moscow, Russia and Moscow Institute of Physics and Technology, 141700 Dolgoprudny (Russian Federation)
2014-10-15T23:59:59.000Z
Single-particle spectroscopic factors (SF) of magic and semimagic nuclei are analyzed within the self-consistent theory of finite Fermi systems. The the in-volume energy dependence of the mass operator ? is taken into account in addition to the energy dependence induced by the surface-phonon coupling effects which is commonly considered. It appears due to the effect of high-lying collective and non-collective particle-hole excitations and persists in nuclear matter. The self-consistent basis of the energy density functional method by Fayans et al. is used. Both the surface and in-volume contributions to the SFs turned out to be of comparable magnitude. Results for magic {sup 208}Pb nucleus and semimagic lead isotopes are presented.
Rainer Jakob
2000-10-16T23:59:59.000Z
We present the handbag contribution to Wide Angle Compton Scattering (WACS) at moderately large momentum transfer obtained with a proton distribution amplitude close to the asymptotic form. In comparison it is found to be significantly larger than results from the hard scattering (pQCD) approach.
Magic wavelengths for the $5s-18s$ transition in rubidium
E. A. Goldschmidt; D. G. Norris; S. B. Koller; R. Wyllie; R. C. Brown; J. V. Porto; U. I. Safronova; M. S. Safronova
2015-03-10T23:59:59.000Z
Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with Rydberg atoms, and reliable theoretical methods to find such magic wavelengths are thus extremely useful. We use a high-precision all-order method to calculate magic wavelengths for the $5s-18s$ transition of rubidium, and compare the calculation to experiment by measuring the light shift for atoms held in an optical dipole trap at a range of wavelengths near a calculated magic value.
Meyer, Sibylle, E-mail: sibylle.meyer@wmi.badw-muenchen.de; Althammer, Matthias; Geprägs, Stephan; Opel, Matthias; Goennenwein, Sebastian T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Gross, Rudolf [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, Technische Universität München, 85748 Garching (Germany)
2014-06-16T23:59:59.000Z
We study the temperature dependence of the spin Hall magnetoresistance (SMR) in yttrium iron garnet/platinum hybrid structures via magnetization orientation dependent magnetoresistance measurements. Our experiments show a decrease of the SMR magnitude with decreasing temperature. Using the sensitivity of the SMR to the spin transport properties of the normal metal, we interpret our data in terms of a decrease of the spin Hall angle in platinum from 0.11 at room temperature to 0.075 at 10?K, while the spin diffusion length and the spin mixing conductance of the ferrimagnetic insulator/normal metal interface remain almost constant.
The robustness of magic state distillation against errors in Clifford gates
Jochym-O'Connor, Tomas; Helou, Bassam; Laflamme, Raymond
2012-01-01T23:59:59.000Z
Quantum error correction and fault-tolerance have provided the possibility for large scale quantum computations without a detrimental loss of quantum information. A very natural class of gates for fault-tolerant quantum computation is the Clifford gate set and as such their usefulness for universal quantum computation is of great interest. Clifford group gates augmented by magic state preparation give the possibility of simulating universal quantum computation. However, experimentally one cannot expect to perfectly prepare magic states. Nonetheless, it has been shown that by repeatedly applying operations from the Clifford group and measurements in the Pauli basis, the fidelity of noisy prepared magic states can be increased arbitrarily close to a pure magic state [1]. We investigate the robustness of magic state distillation to perturbations of the initial states to arbitrary locations in the Bloch sphere due to noise. Additionally, we consider a depolarizing noise model on the quantum gates in the decoding ...
Magic Valley Electric Coop Inc | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLu an Group Jump to:Macquarie Energy LLC JumpMadkini HydroMagic
Angle performance on optima MDxt
David, Jonathan; Kamenitsa, Dennis [Axcelis Technologies, Inc., 108 Cherry Hill Dr, Beverly, MA 01915 (United States)
2012-11-06T23:59:59.000Z
Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).
Laser cooling and trapping of potassium at magic wavelengths
M. S. Safronova; U. I. Safronova; Charles W. Clark
2013-01-14T23:59:59.000Z
We carry out a systematic study of the static and dynamic polarizabilities of the potassium atom using a first-principles high-precision relativistic all-order method in which all single, double, and partial triple excitations of the Dirac-Fock wave functions are included to all orders of perturbation theory. Recommended values are provided for a large number of electric-dipole matrix elements. Static polarizabilities of the 4s, 4p_j, 5s, 5p_j, and 3d_j states are compared with other theory and experiment where available. We use the results of the polarizability calculations to identify magic wavelengths for the 4s-np transitions for $n = 4, 5$, i.e. those wavelengths for which the two levels have the same ac Stark shifts. These facilitate state-insensitive optical cooling and trapping. The magic wavelengths for the $4s-5p$ transitions are of particular interest for attaining a quantum gas of potassium at high phase-space density. We find 20 such wavelengths in the technically interest region of 1050-1130 nm. Uncertainties of all recommended values are estimated.
Boone, C. T.; Nembach, Hans T.; Shaw, Justin M.; Silva, T. J. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)
2013-04-21T23:59:59.000Z
We measured spin-transport in nonferromagnetic (NM) metallic multilayers from the contribution to damping due to spin pumping from a ferromagnetic Co{sub 90}Fe{sub 10} thin film. The multilayer stack consisted of NM{sub 1}/NM{sub 2}/Co{sub 90}Fe{sub 10}(2 nm)/NM{sub 2}/NM{sub 3} with varying NM materials and thicknesses. Using conventional theory for one-dimensional diffusive spin transport in metals, we show that the effective damping due to spin pumping can be strongly affected by the spin transport properties of each NM in the multilayer, which permits the use of damping measurements to accurately determine the spin transport properties of the various NM layers in the full five-layer stack. We find that due to its high electrical resistivity, amorphous Ta is a poor spin conductor, in spite of a short spin-diffusion length of 1.0 nm, and that Pt is an excellent spin conductor by virtue of its low electrical resistivity and a spin diffusion length of only 0.5 nm. Spin Hall effect measurements may have underestimated the spin Hall angle in Pt by assuming a much longer spin diffusion length.
Widespread spin polarization effects in photoemission from topological insulators
Jozwiak, C.; Chen, Y. L.; Fedorov, A. V.; Analytis, J. G.; Rotundu, C. R.; Schmid, A. K.; Denlinger, J. D.; Chuang, Y.-D.; Lee, D.-H.; Fisher, I. R.; Birgeneau, R. J.; Shen, Z.-X.; Hussain, Z.; Lanzara, A.
2011-06-22T23:59:59.000Z
High-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES) was performed on the three-dimensional topological insulator Bi{sub 2}Se{sub 3} using a recently developed high-efficiency spectrometer. The topological surface state's helical spin structure is observed, in agreement with theoretical prediction. Spin textures of both chiralities, at energies above and below the Dirac point, are observed, and the spin structure is found to persist at room temperature. The measurements reveal additional unexpected spin polarization effects, which also originate from the spin-orbit interaction, but are well differentiated from topological physics by contrasting momentum and photon energy and polarization dependencies. These observations demonstrate significant deviations of photoelectron and quasiparticle spin polarizations. Our findings illustrate the inherent complexity of spin-resolved ARPES and demonstrate key considerations for interpreting experimental results.
A New Spin on Photoemission Spectroscopy
Advanced Light Source; Jozwiak, Chris
2008-12-18T23:59:59.000Z
The electronic spin degree of freedom is of general fundamental importance to all matter. Understanding its complex roles and behavior in the solid state, particularly in highly correlated and magnetic materials, has grown increasingly desirable as technology demands advanced devices and materials based on ever stricter comprehension and control of the electron spin. However, direct and efficient spin dependent probes of electronic structure are currently lacking. Angle Resolved Photoemission Spectroscopy (ARPES) has become one of the most successful experimental tools for elucidating solid state electronic structures, bolstered bycontinual breakthroughs in efficient instrumentation. In contrast, spin-resolved photoemission spectroscopy has lagged behind due to a lack of similar instrumental advances. The power of photoemission spectroscopy and the pertinence of electronic spin in the current research climate combine to make breakthroughs in Spin and Angle Resolved Photoemission Spectroscopy (SARPES) a high priority . This thesis details the development of a unique instrument for efficient SARPES and represents a radical departure from conventional methods. A custom designed spin polarimeter based on low energy exchange scattering is developed, with projected efficiency gains of two orders of magnitude over current state-of-the-art polarimeters. For energy analysis, the popular hemispherical analyzer is eschewed for a custom Time-of-Flight (TOF) analyzer offering an additional order of magnitude gain in efficiency. The combined instrument signifies the breakthrough needed to perform the high resolution SARPES experiments necessary for untangling the complex spin-dependent electronic structures central to today?s condensed matter physics.
Magic coins are useful for small-space quantum machines
A. C. Cem Say; Abuzer Yakaryilmaz
2014-11-27T23:59:59.000Z
Although polynomial-time probabilistic Turing machines can utilize uncomputable transition probabilities to recognize uncountably many languages with bounded error when allowed to use logarithmic space, it is known that such "magic coins" give no additional computational power to constant-space versions of those machines. We show that adding a few quantum bits to the model changes the picture dramatically. For every language $L$, there exists such a two-way quantum finite automaton that recognizes a language of the same Turing degree as $L$ with bounded error in polynomial time. When used as verifiers in public-coin interactive proof systems, such automata can verify membership in all languages with bounded error, outperforming their classical counterparts, which are known to fail for the palindromes language.
Nuclear spin circular dichroism
Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland); Rizzo, Antonio [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)] [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy); Kauczor, Joanna; Norman, Patrick [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden)] [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden); Coriani, Sonia, E-mail: coriani@units.it [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)] [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)
2014-04-07T23:59:59.000Z
Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.
Creutz, Michael, E-mail: creutz@bnl.gov
2014-03-15T23:59:59.000Z
Quantum mechanics and relativity in the continuum imply the well known spin–statistics connection. However for particles hopping on a lattice, there is no such constraint. If a lattice model yields a relativistic field theory in a continuum limit, this constraint must “emerge” for physical excitations. We discuss a few models where a spin-less fermion hopping on a lattice gives excitations which satisfy the continuum Dirac equation. This includes such well known systems such as graphene and staggered fermions. -- Highlights: •The spin–statistics theorem is not required for particles on a lattice. •Spin emerges dynamically when spinless fermions have a relativistic continuum limit. •Graphene and staggered fermions are examples of this phenomenon. •The phenomenon is intimately tied to chiral symmetry and fermion doubling. •Anomaly cancellation is a crucial feature of any valid lattice fermion action.
Bound States for Magic State Distillation in Fault-Tolerant Quantum Computation
Earl T. Campbell; Dan E. Browne
2010-02-01T23:59:59.000Z
Magic state distillation is an important primitive in fault-tolerant quantum computation. The magic states are pure non-stabilizer states which can be distilled from certain mixed non-stabilizer states via Clifford group operations alone. Because of the Gottesman-Knill theorem, mixtures of Pauli eigenstates are not expected to be magic state distillable, but it has been an open question whether all mixed states outside this set may be distilled. In this Letter we show that, when resources are finitely limited, non-distillable states exist outside the stabilizer octahedron. In analogy with the bound entangled states, which arise in entanglement theory, we call such states bound states for magic state distillation.
An Examination of Magical Beliefs as Predictors of Obsessive-Compulsive Symptom Dimensions
Spears, Lauren
2014-08-31T23:59:59.000Z
study improved on methodological limitations of previous studies and used the Dimensional Obsessive-Compulsive Scale (DOCS) to conceptualize OCD as a dimensional construct. Relationships between magical belief constructs and four OCD symptom dimensions...
Scientific Highlights from Observations of Active Galactic Nuclei with the MAGIC Telescope
Wagner, Robert [Max-Planck-Institut fuer Physik, D-80805 Muenchen (Germany)
2008-12-24T23:59:59.000Z
Since 2004, the MAGIC {gamma}-ray telescope has newly discovered 6 TeV blazars. The total set of 13 MAGIC-detected active galactic nuclei includes well-studied objects at other wavelengths like Markarian 501 and the giant radio galaxy M 87, but also the distant the flat-spectrum radio quasar 3C 279, and the newly discovered TeV {gamma}-ray emitter S5 0716+71. In addition, also long-term and multi-wavelength studies on well-known TeV blazars and systematic searches for new TeV blazars have been carried out. Here we report selected highlights from recent MAGIC observations of extragalactic TeV {gamma}-ray sources, emphasizing the new physics insights MAGIC was able to contribute.
A Review of "Magic and Masculinity in Early Modern English Drama" by Ian McAdam
Tiffany, Grace
2011-01-01T23:59:59.000Z
that forces readers to reconsider women?s mobility in traversing both physical and culturally sanctioned boundaries. Ian McAdam. Magic and Masculinity in Early Modern English Drama. Pittsburgh: Duquesne University Press, 2009. v + 466 pp. $60. Review... by grace tiffany, western michigan university. Ambitiously, Ian McAdam surveys over half a century?s worth of selected plays by seven major authors to advance his thesis regarding the changing significance of magic and magicians to the early modern...
Dmitriy G. Pavlov; Sergey S. Kokarev
2009-10-20T23:59:59.000Z
Within the framework of Berwald-Moor Geometry in H_3, the paper studies the construction of additive poly-angles (bingles and tringles). It is shown that, considering additiveness in the large, there exist an infinity of such poly-angles.
Classical gravitational spin-spin interaction
W. B. Bonnor
2002-01-30T23:59:59.000Z
I obtain an exact, axially symmetric, stationary solution of Einstein's equations for two massless spinning particles. The term representing the spin-spin interaction agrees with recently published approximate work. The spin-spin force appears to be proportional to the inverse fourth power of the coordinate distance between the particles.
Experimental evidences of a large extrinsic spin Hall effect in AuW alloy
Laczkowski, P.; Rojas-Sánchez, J.-C. [Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 91767 Palaiseau (France); INAC/SP2M, CEA-Université Joseph Fourier, F-38054 Grenoble (France); Savero-Torres, W.; Notin, L.; Beigné, C.; Marty, A.; Attané, J.-P.; Vila, L. [INAC/SP2M, CEA-Université Joseph Fourier, F-38054 Grenoble (France); Jaffrès, H.; Reyren, N.; Deranlot, C.; George, J.-M.; Fert, A. [Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 91767 Palaiseau (France)
2014-04-07T23:59:59.000Z
We report an experimental study of a gold-tungsten alloy (7 at. % W concentration in Au host) displaying remarkable properties for spintronics applications using both magneto-transport in lateral spin valve devices and spin-pumping with inverse spin Hall effect experiments. A very large spin Hall angle of about 10% is consistently found using both techniques with the reliable spin diffusion length of 2?nm estimated by the spin sink experiments in the lateral spin valves. With its chemical stability, high resistivity, and small induced damping, this AuW alloy may find applications in the nearest future.
Wang, Hailong; Du, Chunhui; Chris Hammel, P., E-mail: hammel@physics.osu.edu; Yang, Fengyuan, E-mail: fyyang@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)
2014-05-19T23:59:59.000Z
Using ferromagnetic (FM) resonance spin pumping, we observe injection of spin currents from Y{sub 3}Fe{sub 5}O{sub 12} (YIG) films to FM metals, including Ni{sub 81}Fe{sub 19} (Py), Fe, Co, and Ni, and detection of spin currents by inverse spin Hall effect (ISHE) in the FM metals. We obtain a high effective spin mixing conductance of 6.3?×?10{sup 18}?m{sup ?2} in a YIG/Cu/Py trilayer and a spin Hall angle of 0.020 for Py. The spin pumping signals in Fe, Co, and Ni confirm the mechanism of ISHE in FMs is the inverse process of the anomalous Hall effect.
Discovery of TeV gamma-ray emission from the Pulsar Wind Nebula 3C 58 by MAGIC
Bigas, O Blanch; Carmona, E; Pérez-Torres, M A
2015-01-01T23:59:59.000Z
The Pulsar Wind Nebula (PWN) 3C 58 is energized by one of the highest spin-down power pulsars known (5% of Crab pulsar) and it has been compared to the Crab Nebula due to their morphological similarities. This object was detected by Fermi-LAT with a spectrum extending beyond 100 GeV. We analyzed 81 hours of 3C 58 data taken with the MAGIC telescopes and we detected VHE gamma-ray emission for the first time at TeV energies with a significance of 5.7 sigma and an integral flux of 0.65% C.U. above 1 TeV. The differential energy spectrum between 400 GeV and 10 TeV is well described by a power-law function $d\\Phi/dE=f_{o}(E/1TeV)^{-\\Gamma}$ with $f_{o}=(2.0\\pm0.4stat\\pm0.6sys) 10^{-13}cm^{-2}s^{-1}TeV^{-1}$ and $\\Gamma=2.4\\pm0.2sta\\pm0.2sys$. This leads 3C 58 to be the least luminous PWN ever detected at VHE and the one with the lowest flux at VHE to date. According to time-dependent models in which electrons up-scatter photon fields, the best representation favors a distance to the PWN of 2 kpc and FIR comparable...
Angling chromium to let oxygen through | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Angling chromium to let oxygen through Angling chromium to let oxygen through Released: September 10, 2014 New semiconducting material works at lower temperatures Scanning...
Magic state distillation in all prime dimensions using quantum Reed-Muller codes
Campbell, Earl T; Browne, Dan E
2012-01-01T23:59:59.000Z
We propose families of protocols for magic state distillation -- important components of fault tolerance schemes --- for systems of odd prime dimension. Our protocols utilize quantum Reed-Muller codes with transversal non-Clifford gates. We find that in higher dimensions smaller codes can be used than one might expect based on qubit codes. All our protocols produce magic states at a resource cost that increases only polynomially with the inverse of the final ouput error probability. We give specific details for 3-dimensional systems, where we find that certain magic states can be distilled provided an initial error probability of less than 20.02% or a depolarizing noise rate of less than 31.7%. This is the largest error probability threshold of all known protocols with polynomial resource cost. For a depolarizing noise model we also give distillation thresholds for odd prime dimensions up-to 19.
Spin rotation of polarized beams in high energy storage ring
V. G. Baryshevsky
2006-03-23T23:59:59.000Z
The equations for spin evolution of a particle in a storage ring are obtained considering contributions from the tensor electric and magnetic polarizabilities of the particle along with the contributions from spin rotation and birefringence effect in polarized matter of an internal target. % Study of the spin rotation and birefringence effects for a particle in a high energy storage ring provides for measurement both the spin-dependent real part of the coherent elastic zero-angle scattering amplitude and tensor electric (magnetic) polarizabilities.
Wells, Kimberly Ann
2007-09-17T23:59:59.000Z
differences from the already well known social-protest genre of Magical Realism. The texts examined include Nalo Hopkinson’s Brown Girl in the Ring (1998), Alice Hoffman’s Practical Magic (1996), Chitra Divakaruni’s Mistress of Spices (1997), 5 Sean Stewart.... These witches are women who make their own rules, frequently in opposition to patriarchal ones that say a woman should endure abuse, suppress her own desires and choices in favor of those of her husband, or father, or accept her fate as powerless victim...
"The Magic of Words": the writer as curandero in the works of Rudolfo A. Anaya
Sanchez, Katherine Jeanine Cecil
1995-01-01T23:59:59.000Z
"THE MAGIC OF WORDS:" THE WRITER AS CURANDERO IN THE WORKS OF RUDOLFO A. ANAYA A Thesis by KATHERINE JEANINE CECIL SANCHEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF ARTS December 1995 Major Subject: English "THE MAGIC OF WORDS:" THE WRITER AS CURANDERO IN THE WORKS OF RUDOLFO A. ANAYA A Thesis by KATHERINE JEANINE CECIL SANCHEZ Submitted to Texas AkM University in partial fulfillment...
Demand Response Spinning Reserve Demonstration
2007-01-01T23:59:59.000Z
F) Enhanced ACP Date RAA ACP Demand Response – SpinningReserve Demonstration Demand Response – Spinning Reservesupply spinning reserve. Demand Response – Spinning Reserve
Liquid Crystal Pretilt and Azimuth Angle Study of Stacked Alignment Layers
angles for the liquid crystal. It is based on stacking both photo- aligned polymer and rubbed polyimide comprise of both photo-aligned horizontal polymer and rubbed vertical polyimide. The advantage alignment polyimide JALS2021 form JSR Corporation is spin coated on the substrate. Then it is baked inside
Simone Sturniolo; Marco Pieruccini; Maurizio Corti; Attilio Rigamonti
2014-05-20T23:59:59.000Z
Novel methods to analyze NMR signals dominated by dipolar interaction are applied to the study of slow relaxation motions in polybutadiene approaching its glass transition temperature. The analysis is based on a recently developed model where the time dependence in an ensemble of dipolar interacting spin pairs is described without resorting to the Anderson-Weiss approximation. The ability to catch relevant features of the $\\alpha$ relaxation process is emphasized. In particular, it is shown that the temperature profile of the Magic Sandwich Echo efficiency carries information on the frequency profile of the $\\alpha$-process. The analysis is corroborated by the temperature dependence of the spin-lattice relaxation time.
The Universe Viewed in Gamma-Rays 1 The Control System of the MAGIC telescope
Enomoto, Ryoji
will be commissioned during this year. The control system of the telescope is distributed over a number of functional on the Central Control and Camera Control systems. 1. Introduction MAGIC[1] is a new generation Imaging Air Cherenkov Telescope (IACT) allocated at the IAC site in the Canary island of La Palma. The aim of the tele
Magic Lenses for Revealing Device Interactions in Smart Environments (demo abstract)
devices in the camera's field of view. Keywords: Smart Environment, Web of Things, Network Man- agement, a storage back-end to persist recorded messages, and a magic lens-like [Bier et al. 1993] handheld user et al. 2013] where underground tubing is visualized using an aug- mented reality application
Magic mode switching in Yb:CaGdAlO4 laser under high pump power
and interesting properties for high- power and ultra-short-pulse lasers. In fact, by combining both broad emission bandwidth and good thermal prop- erties, it permits us to demonstrate ultra-short pulses [1,2] and highMagic mode switching in Yb:CaGdAlO4 laser under high pump power Frédéric Druon,1, * Mickaël Olivier
Conversion of pure spin current to charge current in amorphous bismuth
Emoto, H.; Ando, Y.; Shinjo, T.; Shiraishi, M., E-mail: shiraishi@ee.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, Osaka 560-8531 (Japan); Shikoh, E. [Graduate School of Engineering, Osaka City University, Osaka 558-8585 (Japan); Fuseya, Y. [Department of Applied Physics and Chemistry, The University of Electro-Communications, Tokyo 182-8585 (Japan)
2014-05-07T23:59:59.000Z
Spin Hall angle and spin diffusion length in amorphous bismuth (Bi) are investigated by using conversion of a pure spin current to a charge current in a spin pumping technique. In Bi/Ni{sub 80}Fe{sub 20}/Si(100) sample, a clear direct current (DC) electromotive force due to the inverse spin Hall effect of the Bi layer is observed at room temperature under a ferromagnetic resonance condition of the Ni{sub 80}Fe{sub 20} layer. From the Bi thickness dependence of the DC electromotive force, the spin Hall angle and the spin diffusion length of the amorphous Bi film are estimated to be 0.02 and 8?nm, respectively.
OPENING ANGLES OF COLLAPSAR JETS
Mizuta, Akira; Ioka, Kunihito [Theory Center, Institute of Particle and Nuclear Studies, KEK, Tsukuba 305-0801 (Japan)
2013-11-10T23:59:59.000Z
We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by ?{sub j} ? 1/5?{sub 0} and infer the initial Lorentz factor of the jet at the central engine, ?{sub 0}, is a few for existing observations of ?{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle ?{sub j,{sub max}} ? 1/5 ? 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.
Protein MAS NMR methodology and structural analysis of protein assemblies
Bayro, Marvin J
2010-01-01T23:59:59.000Z
Methodological developments and applications of solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, with particular emphasis on the analysis of protein structure, are described in this thesis. ...
Ong, Ta-Chung
We employ a combination of [superscript 13]C/[superscript 15]N magic angle spinning (MAS) NMR and [superscript 2]H NMR to study the structural and functional consequences of different membrane environments on VDAC1 and, ...
Higher Order Amyloid Fibril Structure by MAS NMR and DNP Spectroscopy
Debelouchina, Galia T.
Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary ...
Andreas, Loren B.
We demonstrate the use of dynamic nuclear polarization (DNP) to elucidate ligand binding to a membrane protein using dipolar recoupling magic angle spinning (MAS) NMR. In particular, we detect drug binding in the proton ...
Maly, Thorsten
Perdeuteration of biological macromolecules for magic angle spinning solid-state NMR spectroscopy can yield high-resolution [superscript 2]H–[superscript 13]C correlation spectra and the method is therefore of great interest ...
DNP-Enhanced MAS NMR of Bovine Serum Albumin Sediments and Solutions
Ravera, Enrico
Protein sedimentation sans cryoprotection is a new approach to magic angle spinning (MAS) and dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) spectroscopy of proteins. It increases the sensitivity of ...
Daviso, Eugenio
Resonance assignment is the first step in NMR structure determination. For magic angle spinning NMR, this is typically achieved with a set of heteronuclear correlation experiments (NCaCX, NCOCX, CONCa) that utilize SPECIFIC-CP ...
Guenther, Johannes 1983-
2012-08-16T23:59:59.000Z
decay (NMR), flame ionization detector FRPSG fluorous reversed phase silica gel xxiv GC gas chromatography h hour HRMAS high-resolution magic angle spinning HR-MS high-resolution mass spectrometry Hz Hertz i iso J scalar coupling...
ON THE PROSPECT OF CONSTRAINING BLACK HOLE SPIN THROUGH X-RAY SPECTROSCOPY OF HOTSPOTS
Yaqoob, Tahir
Future X-ray instrumentation is expected to allow us to significantly improve the constraints derived from the Fe?K lines in active galactic nuclei, such as the black hole angular momentum (spin) and the inclination angle ...
Mosendz, O.; Vlaminck, V.; Pearson, J. E.; Fradin, F. Y.; Bauer, G. E. W.; Bader, S. D.; Hoffmann, A.; Delft Univ. of Technology
2010-12-01T23:59:59.000Z
Spin pumping is a mechanism that generates spin currents from ferromagnetic resonance over macroscopic interfacial areas, thereby enabling sensitive detection of the inverse spin Hall effect that transforms spin into charge currents in nonmagnetic conductors. Here we study the spin-pumping-induced voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers integrated into coplanar waveguides for different normal metals and as a function of angle of the applied magnetic field direction, as well as microwave frequency and power. We find good agreement between experimental data and a theoretical model that includes contributions from anisotropic magnetoresistance and inverse spin Hall effect. The analysis provides consistent results over a wide range of experimental conditions as long as the precise magnetization trajectory is taken into account. The spin Hall angles for Pt, Pd, Au, and Mo were determined with high precision to be 0.013 {+-} 0.002, 0.0064 {+-} 0.001, 0.0035 {+-} 0.0003, and -0.0005 {+-} 0.0001, respectively.
All-electric and all-semiconductor spin field effect transistors
Chuang, Pojen; Ho, Sheng-Chin; Smith, L. W.; Sfigakis, F.; Pepper, M.; Chen, Chin-Hung; Fan, Ju-Chun; Griffiths, J. P.; Farrer, I.; Beere, H. E.; Jones, G. A. C.; Ritchie, D. A.; Chen, T.-M.
2015-01-01T23:59:59.000Z
which suffers from low signal levels as a result of the limited spin-injection efficiency, the short spin lifetime, and the spread of spin precession angles. The voltage oscillation disappears when the lateral inversion asymmetry is removed from the QPCs... to showing the realization of spin FETs, provide the first direct evidence of spin polarization of QPCs at zero external magnetic field. Figure 3a shows the oscillating voltages when the injector and detector QPCs are set at various conductance values. In a...
Negative Quasi-Probability Representation is a Necessary Resource for Magic State Distillation
Veitch, Victor; Emerson, Joseph
2012-01-01T23:59:59.000Z
The magic state model of quantum computation gives a recipe for universal quantum computation using perfect Clifford operations and repeat preparations of a noisy ancilla state. It is an open problem to determine which ancilla states enable universal quantum computation in this model. Here we show that for systems of odd dimension a necessary condition for a state to enable universal quantum computation is that it have negative representation in a particular quasi-probability representation which is a discrete analogue to the Wigner function. This condition implies the existence of a large class of bound states for magic state distillation: states which cannot be prepared using Clifford operations but do not enable universal quantum computation. This condition also enables an efficient experimental test for distillability.
The MAGIC Telescope Project for Gamma Astronomy above 10 GeV
N. Magnussen
1998-05-14T23:59:59.000Z
A project to construct a 17 m diameter imaging air Cherenkov telescope, called the MAGIC Telescope, is described. The aim of the project is to close the observation gap in the gamma-ray sky extending from 10 GeV as the highest energy measurable by space-borne experiments to 300 GeV, the lowest energy measurable by the current generation of ground-based Cherenkov telescopes. The MAGIC Telescope will incorporate several new features in order to reach the very low energy threshold. At the same time the new technology will yield an improvement in sensitivity in the energy region where current Cherenkov telescopes are measuring by about an order of magnitude.
Spin Rotation of Formalism for Spin Tracking
Luccio,A.
2008-02-01T23:59:59.000Z
The problem of which coefficients are adequate to correctly represent the spin rotation in vector spin tracking for polarized proton and deuteron beams in synchrotrons is here re-examined in the light of recent discussions. The main aim of this note is to show where some previous erroneous results originated and how to code spin rotation in a tracking code. Some analysis of a recent experiment is presented that confirm the correctness of the assumptions.
Enhancement of nonlocal spin-valve signal using spin accumulation in local spin-valve configuration
Otani, Yoshichika
Enhancement of nonlocal spin-valve signal using spin accumulation in local spin-valve configuration) We propose a nonlocal spin-valve measurement combined with a local spin-valve structure to enlarge spin signal. The probe configuration consists of a lateral spin valve with three NiFe wires bridged
Spin - or, actually: Spin and Quantum Statistics
Juerg Froehlich
2008-02-29T23:59:59.000Z
The history of the discovery of electron spin and the Pauli principle and the mathematics of spin and quantum statistics are reviewed. Pauli's theory of the spinning electron and some of its many applications in mathematics and physics are considered in more detail. The role of the fact that the tree-level gyromagnetic factor of the electron has the value g = 2 in an analysis of stability (and instability) of matter in arbitrary external magnetic fields is highlighted. Radiative corrections and precision measurements of g are reviewed. The general connection between spin and statistics, the CPT theorem and the theory of braid statistics are described.
Hybrid magic state distillation for universal fault-tolerant quantum computation
Wenqiang Zheng; Yafei Yu; Jian Pan; Jingfu Zhang; Jun Li; Zhaokai Li; Dieter Suter; Xianyi Zhou; Xinhua Peng; Jiangfeng Du
2014-12-11T23:59:59.000Z
A set of stabilizer operations augmented by some special initial states known as 'magic states', gives the possibility of universal fault-tolerant quantum computation. However, magic state preparation inevitably involves nonideal operations that introduce noise. The most common method to eliminate the noise is magic state distillation (MSD) by stabilizer operations. Here we propose a hybrid MSD protocol by connecting a four-qubit H-type MSD with a five-qubit T-type MSD, in order to overcome some disadvantages of the previous MSD protocols. The hybrid MSD protocol further integrates distillable ranges of different existing MSD protocols and extends the T-type distillable range to the stabilizer octahedron edges. And it provides considerable improvement in qubit cost for almost all of the distillable range. Moreover, we experimentally demonstrate the four-qubit H-type MSD protocol using nuclear magnetic resonance technology, together with the previous five-qubit MSD experiment, to show the feasibility of the hybrid MSD protocol.
Magnetohydrodynamic spin waves in degenerate electron-positron-ion plasmas
Mushtaq, A. [TPPD, PINSTECH Nilore, 44000 Islamabad (Pakistan); National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Maroof, R.; Ahmad, Zulfiaqr [Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan); Qamar, A. [National Center for Physics, Shahdrah Valley Road, 44000 Islamabad (Pakistan); Institute of Physics and Electronics, University of Peshawar, 25000 Peshawar (Pakistan)
2012-05-15T23:59:59.000Z
Low frequency magnetosonic waves are studied in magnetized degenerate electron-positron-ion plasmas with spin effects. Using the fluid equations of magnetoplasma with quantum corrections due to the Bohm potential, temperature degeneracy, and spin magnetization energy, a generalized dispersion relation for oblique magnetosonic waves is derived. Spin effects are incorporated via spin force and macroscopic spin magnetization current. For three different values of angle {theta}, the generalized dispersion relation is reduced to three different relations under the low frequency magnetohydrodynamic assumptions. It is found that the effect of quantum corrections in the presence of positron concentration significantly modifies the dispersive properties of these modes. The importance of the work relevant to compact astrophysical bodies is pointed out.
Cahaya, Adam B.; Tretiakov, O. A. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Bauer, Gerrit E. W. [Institute for Materials Research and WPI-AIMR, Tohoku University, Sendai 980-8577 (Japan); Kavli Institute of NanoScience, TU Delft Lorentzweg 1, 2628 CJ Delft (Netherlands)
2014-01-27T23:59:59.000Z
We derive expressions for the efficiency and figure of merit of two spin caloritronic devices based on the spin Seebeck effect (SSE), i.e., the generation of spin currents by a temperature gradient. The inverse spin Hall effect is conventionally used to detect the SSE and offers advantages for large area applications. We also propose a device that converts spin current into electric one by means of a spin-valve detector, which scales favorably to small sizes and approaches a figure of merit of 0.5 at room temperature.
Caustic graphene plasmons with Kelvin angle
Shi, Xihang; Gao, Fei; Xu, Hongyi; Yang, Zhaoju; Zhang, Baile
2015-01-01T23:59:59.000Z
A century-long argument made by Lord Kelvin that all swimming objects have an effective Mach number of 3, corresponding to the Kelvin angle of 19.5 degree for ship waves, has been recently challenged with the conclusion that the Kelvin angle should gradually transit to the Mach angle as the ship velocity increases. Here we show that a similar phenomenon can happen for graphene plasmons. By analyzing the caustic wave pattern of graphene plasmons stimulated by a swift charged particle moving uniformly above graphene, we show that at low velocities of the charged particle, the caustics of graphene plasmons form the Kelvin angle. At large velocities of the particle, the caustics disappear and the effective semi-angle of the wave pattern approaches the Mach angle. Our study introduces caustic wave theory to the field of graphene plasmonics, and reveals a novel physical picture of graphene plasmon excitation during electron energy-loss spectroscopy measurement.
Precessional magnetization induced spin current from CoFeB into Ta
Jamali, Mahdi; Klemm, Angeline; Wang, Jian-Ping, E-mail: jpwang@umn.edu [Department of Electrical and Computer Engineering, University of Minnesota, 4-174 200 Union Street SE, Minneapolis, Minnesota 55455 (United States)] [Department of Electrical and Computer Engineering, University of Minnesota, 4-174 200 Union Street SE, Minneapolis, Minnesota 55455 (United States)
2013-12-16T23:59:59.000Z
The spin dynamics at the interface between the CoFeB and Ta layer has been studied using spin pumping and spin wave characterizations. The spin pumping driven by the ferromagnetic resonance in the CoFeB layer injects a spin current into Ta layer which results in an electromotive force across the Ta layer due to the inverse spin Hall effect. Upon changing the polarity of the bias magnetic field, the polarity of the output voltage inverts and the output voltage increases linearly in respect to the microwave signal power which are consistent with the spin pumping characteristics. The effect of the in-plane magnetization angle on the output voltage has been studied. Furthermore, it is found that the frequency spectrum of the spin Hall voltage is modified by the annealing temperature and the full width at half maximum of the spin pumping increases by more than 40% with the increase of the annealing temperature from 200?°C to 300?°C. The spin Hall angle at the Ta-CoFeB interface is determined to be 0.014, and the damping constant of the CoFeB increases from 0.006 in pure CoFeB to 0.015 in Ta/CoFeB film.
ETEAPOT: symplectic orbit/spin tracking code for all-electric storage rings
Talman, Richard M
2015-01-01T23:59:59.000Z
Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring "trap". At the "magic" kinetic energy of 232.792 MeV, proton spins are "frozen", for example always parallel to the instantaneous particle momentum. This paper describes an accelerator simulation code, ETEAPOT, a new component of the Unified Accelerator Libraries (UAL), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the non-constant particle velocity in electric rings give them significantly different properties, especially in weak focusing rings. Like the earlier code TEAPOT (for magnetic ring simulation) this code performs \\emph{exact tracking in an idealized (approximate) lattice} rather than the more conventional approach, which is \\emph{approximate tracking in a more nearly exact lattice.} The BMT equation des...
Optical detection of spin Hall effect in metals
Erve, O. M. J. van ‘t, E-mail: Olaf.Vanterve@nrl.navy.mil; Hanbicki, A. T.; McCreary, K. M.; Li, C. H.; Jonker, B. T. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)
2014-04-28T23:59:59.000Z
Optical techniques have been widely used to probe the spin Hall effect in semiconductors. In metals, however, only electrical methods such as nonlocal spin valve transport, ferromagnetic resonance, or spin torque transfer experiments have been successful. These methods require complex processing techniques and measuring setups. We show here that the spin Hall effect can be observed in non-magnetic metals such as Pt and ?-W, using a standard bench top magneto-optical Kerr system with very little sample preparation. Applying a square wave current and using Fourier analysis significantly improve our detection level. One can readily determine the angular dependence of the induced polarization on the bias current direction (very difficult to do with voltage detection), the orientation of the spin Hall induced polarization, and the sign of the spin Hall angle. This optical approach is free from the complications of various resistive effects, which can compromise voltage measurements. This opens up the study of spin Hall effect in metals to a variety of spin dynamic and spatial imaging experiments.
RECOILING SUPERMASSIVE BLACK HOLES IN SPIN-FLIP RADIO GALAXIES
Liu, F. K.; Wang Dong [Department of Astronomy, Peking University, 100871 Beijing (China); Chen Xian, E-mail: fkliu@pku.edu.cn [Kavli Institute for Astronomy and Astrophysics, Peking University, 100871 Beijing (China)
2012-02-20T23:59:59.000Z
Numerical relativity simulations predict that coalescence of supermassive black hole (SMBH) binaries leads not only to a spin flip but also to a recoiling of the merger remnant SMBHs. In the literature, X-shaped radio sources are popularly suggested to be candidates for SMBH mergers with spin flip of jet-ejecting SMBHs. Here we investigate the spectral and spatial observational signatures of the recoiling SMBHs in radio sources undergoing black hole spin flip. Our results show that SMBHs in most spin-flip radio sources have mass ratio q {approx}> 0.3 with a minimum possible value q{sub min} {approx_equal} 0.05. For major mergers, the remnant SMBHs can get a kick velocity as high as 2100 km s{sup -1} in the direction within an angle {approx}< 40 Degree-Sign relative to the spin axes of remnant SMBHs, implying that recoiling quasars are biased to be with high Doppler-shifted broad emission lines while recoiling radio galaxies are biased to large apparent spatial off-center displacements. We also calculate the distribution functions of line-of-sight velocity and apparent spatial off-center displacements for spin-flip radio sources with different apparent jet reorientation angles. Our results show that the larger the apparent jet reorientation angle is, the larger the Doppler-shifting recoiling velocity and apparent spatial off-center displacement will be. We investigate the effects of recoiling velocity on the dust torus in spin-flip radio sources and suggest that recoiling of SMBHs would lead to 'dust-poor' active galactic nuclei. Finally, we collect a sample of 19 X-shaped radio objects and for each object give the probability of detecting the predicted signatures of recoiling SMBH.
Spinning particles and higher spin field equations
Bastianelli, Fiorenzo; Corradini, Olindo; Latini, Emanuele
2015-01-01T23:59:59.000Z
Relativistic particles with higher spin can be described in first quantization using actions with local supersymmetry on the worldline. First, we present a brief review of these actions and their use in first quantization. In a Dirac quantization scheme the field equations emerge as Dirac constraints on the Hilbert space, and we outline how they lead to the description of higher spin fields in terms of the more standard Fronsdal-Labastida equations. Then, we describe how these actions can be extended so that the propagating particle is allowed to take different values of the spin, i.e. carry a reducible representation of the Poincar\\'e group. This way one may identify a four dimensional model that carries the same degrees of freedom of the minimal Vasiliev's interacting higher spin field theory. Extensions to massive particles and to propagation on (A)dS spaces are also briefly commented upon.
Xinyu Zhao; Peihao Huang; Xuedong Hu
2015-02-27T23:59:59.000Z
We study relaxation of a moving spin qubit caused by phonon noise. As we vary the speed of the qubit, we observe several interesting features in spin relaxation and the associated phonon emission, induced by Doppler effect. In particular, in the supersonic regime, the phonons emitted by the relaxing qubit is concentrated along certain directions, similar to the shock waves produced in classical Cherenkov effect. As the speed of the moving qubit increases from the subsonic regime to the supersonic regime, the qubit experiences a peak in the spin relaxation rate near the speed of sound, which we term a spin relaxation boom in analogy to the classical sonic boom. We also find that the moving spin qubit may have a lower relaxation rate than a static qubit, which hints at the possibility of coherence-preserving transportation for a spin qubit. While the physics we have studied here has strong classical analogies, we do find that quantum confinement for the spin qubit plays an important role in all the phenomena we observe. Specifically, it produces a correction on the Cherenkov angle, and removes the divergence in relaxation rate at the sonic barrier. It is our hope that our results would encourage further research into approaches for transferring and preserving quantum information in spin qubit architectures.
Selective population and neutron decay of the first excited state of semi-magic O-23
A. Schiller; N. Frank; T. Baumann; D. Bazin; B. A. Brown; J. Brown; P. A. DeYoung; J. E. Finck; A. Gade; J. Hinnefeld; R. Howes; J. -L. Lecouey; B. Luther; W. A. Peters; H. Scheit; M. Thoennessen; J. A. Tostevin
2006-12-21T23:59:59.000Z
We have observed an excited state in the neutron-rich semi-magic nucleus O-23 for the first time. No such states have been found in previous searches using gamma-ray spectroscopy. The observation of a resonance in n-fragment coincidence measurements confirms the speculation in the literature that the lowest excited state is neutron unbound and establishes positive evidence for a 2.8(1) MeV excitation energy of the first excited state in O-23. The non-observation of a predicted second excited state is explained assuming selectivity of inner-shell knockout reactions.
DOE/SC-ARM-12-020 MAGIC: Marine ARM GPCI Investigation of Clouds
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi SitePARTOffice ofHale Plan24,7,INL is6 ARM20 MAGIC:
The effect of knee separation and backrest angle on lumbar lordosis angle in various seated postures
Bolen, Bradley Kyle
1999-01-01T23:59:59.000Z
of the influence of backrest inclination on lumbar lordosis have shown that as trunk-thigh angle increases from the vertical, lumbar lordosis likewise increases towards a more neutral posture (Bridger er al 1989b, Keegan 1953). Keegan reported that the neutral...'il, ", ' " r 20. 32 35, 56 Knee Separation (cmi Figure 5 Lordotic angles for females with backrest at 90-deg Lordotic Angles for Females with Seat Back Angle of 105 Degrees p =0. 881 5. 08 e0 3'r 35. 56 Knoe S. 'prwation (cm} Lordotic Angles for Fcmalcs...
Anomalous Cherenkov spin-orbit sound
Smirnov, Sergey [Institut fuer Theoretische Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)
2011-02-15T23:59:59.000Z
The Cherenkov effect is a well-known phenomenon in the electrodynamics of fast charged particles passing through transparent media. If the particle is faster than the light in a given medium, the medium emits a forward light cone. This beautiful phenomenon has an acoustic counterpart where the role of photons is played by phonons and the role of the speed of light is played by the sound velocity. In this case the medium emits a forward sound cone. Here, we show that in a system with spin-orbit interactions in addition to this normal Cherenkov sound there appears an anomalous Cherenkov sound with forward and backward sound propagation. Furthermore, we demonstrate that the transition from the normal to anomalous Cherenkov sound happens in a singular way at the Cherenkov cone angle. The detection of this acoustic singularity therefore represents an alternative experimental tool for the measurement of the spin-orbit coupling strength.
Torczynski, John R. (Albuquerque, NM)
2000-01-01T23:59:59.000Z
A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.
Contact Angle Hysteresis on Superhydrophobic Stripes
Alexander L. Dubov; Ahmed Mourran; Martin Möller; Olga I. Vinogradova
2014-07-21T23:59:59.000Z
We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, $\\phi_S$. It is shown that the receding regime is determined by a longitudinal sliding motion the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e. is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with $\\phi_S$, in contrast to predictions of the Cassie equation. To interpret this we develop a simple theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the elastic energy of strong defects at the borders of stripes, which scales as $\\phi_S^2 \\ln \\phi_S$. The advancing contact angle was found to be anisotropic, except as in a dilute regime, and its value is determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on $\\phi_S$, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at $\\phi_S\\simeq 0.5$. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be proportional to $\\phi_S^2$. Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when $\\phi_S\\leq 0.2$.
Effect of spin rotation coupling on spin transport
Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com
2013-12-15T23:59:59.000Z
We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup ?}?p{sup ?} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup ?}?p{sup ?} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.
05Mar09 ANALYSISIn crisis, GE finds its deep bench not so magical By James B. Kelleher
Kuzmanovic, Aleksandar
05Mar09 ANALYSISIn crisis, GE finds its deep bench not so magical By James B. Kelleher not true." HANGING ON THE HUDSON At the heart of GE's training program is the Leadership Center faces its worst crisis in decades, its managers seem suddenly bereft of good ideas, its deep bench
Stetter, Joseph R. (Naperville, IL); Maclay, G. Jordan (Maywood, IL)
1989-01-01T23:59:59.000Z
Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.
Inertial effect on spin–orbit coupling and spin transport
Basu, B., E-mail: sribbasu@gmail.com; Chowdhury, Debashree, E-mail: debashreephys@gmail.com
2013-08-15T23:59:59.000Z
We theoretically study the renormalization of inertial effects on the spin dependent transport of conduction electrons in a semiconductor by taking into account the interband mixing on the basis of k{sup ?}?p{sup ?} perturbation theory. In our analysis, for the generation of spin current we have used the extended Drude model where the spin–orbit coupling plays an important role. We predict enhancement of the spin current resulting from the renormalized spin–orbit coupling effective in our model in cubic and non-cubic crystals. Attention has been paid to clarify the importance of gauge fields in the spin transport of this inertial system. A theoretical proposition of a perfect spin filter has been done through the Aharonov–Casher like phase corresponding to this inertial system. For a time dependent acceleration, effect of k{sup ?}?p{sup ?} perturbation on the spin current and spin polarization has also been addressed. Furthermore, achievement of a tunable source of polarized spin current through the non uniformity of the inertial spin–orbit coupling strength has also been discussed. -- Highlights: •Study of the renormalization of inertial spin dependent transport of electrons. •Enhancement of the spin current due to the renormalized spin–orbit coupling. •A theoretical proposition of a perfect spin filter. •For a time dependent acceleration, spin current, spin polarization is addressed.
Spin polarization and magnetic dichroism in core-level photoemission from ferromagnets
Menchero, J G [Univ. of California, Berkeley, CA (United States). Dept. of Physics
1997-05-01T23:59:59.000Z
In this thesis we present a theoretical investigation of angle- and spin-resolved core-level photoemission from ferromagnetic Fe and Ni. We also consider magneto-dichroic effects due to reversal of the photon helicity or reversal of the sample magnetization direction. In chapter 1, we provide a brief outline of the history of photoemission, and show how it has played an important role in the development of modern physics. We then review the basic elements of the theory of core-level photoemission, and discuss the validity of the some of the commonly-used approximations. In chapter 2, we present a one-electron theory to calculate spin- and angle-resolved photoemission spectra for an arbitrary photon polarization. The Hamiltonian includes both spin-orbit and exchange interactions. As test cases for the theory, we calculate the spin polarization and magnetic dichroism for the Fe 2p core level, and find that agreement with experiment is very good.
Overview of Processes Involved in Spin Transfer Collisions
Buttimore, N. H. [Trinity College, Dublin (Ireland)
2008-04-30T23:59:59.000Z
An outline is provided of methods for polarizing antiprotons that include the possible use of channelling in a bent crystal and also the technique of scattering off leptons or protons at a suitably small angle. In the method of channelling it is suggested that the angular dependence of the analysing power of the incident particle is cubic in the angle for single scattering in the crystal when this takes place within the region of electromagnetic hadronic interference as is most likely for channelled particles. Polarization transfer in the scattering of antiprotons off leptons or protons is discussed in addition where emphasis is laid on the angular integrals over spin observables appropriate for spin filtering.
Small Angle X-Ray Scattering Detector
Hessler, Jan P.
2004-06-15T23:59:59.000Z
A detector for time-resolved small-angle x-ray scattering includes a nearly constant diameter, evacuated linear tube having an end plate detector with a first fluorescent screen and concentric rings of first fiber optic bundles for low angle scattering detection and an annular detector having a second fluorescent screen and second fiber optic bundles concentrically disposed about the tube for higher angle scattering detection. With the scattering source, i.e., the specimen under investigation, located outside of the evacuated tube on the tube's longitudinal axis, scattered x-rays are detected by the fiber optic bundles, to each of which is coupled a respective photodetector, to provide a measurement resolution, i.e., dq/q, where q is the momentum transferred from an incident x-ray to an x-ray scattering specimen, of 2% over two (2) orders of magnitude in reciprocal space, i.e., qmax/qmin approx=lO0.
Particle-vibration coupling effect on the $\\beta$-decay of magic nuclei
Niu, Yifei; Colo, Gianluca; Vigezzi, Enrico
2015-01-01T23:59:59.000Z
Nuclear $\\beta$-decay in magic nuclei is investigated, taking into account the coupling between particle and collective vibrations,on top of self-consistent random phase approximation calculations based on Skyrme density functionals. The low-lying Gamow-Teller strength is shifted downwards and at times becomes fragmented; as a consequence, the $\\beta$-decay half-lives are reduced due to the increase of the phase space available for the decay. In some cases, this leads to a very good agreement between theoretical and experimental lifetimes: this happens, in particular, in the case of the Skyrme force SkM*, that can also reproduce the line shape of the high energy Gamow-Teller resonance as it was previously shown.
Algebraic spin liquid in an exactly solvable spin model
Yao, Hong; Zhang, Shou-Cheng; Kivelson, Steven A.; /Stanford U., Phys. Dept.
2010-03-25T23:59:59.000Z
We have proposed an exactly solvable quantum spin-3/2 model on a square lattice. Its ground state is a quantum spin liquid with a half integer spin per unit cell. The fermionic excitations are gapless with a linear dispersion, while the topological 'vison' excitations are gapped. Moreover, the massless Dirac fermions are stable. Thus, this model is, to the best of our knowledge, the first exactly solvable model of half-integer spins whose ground state is an 'algebraic spin liquid.'
Molecular Magic -1 Molecular Magic
Tittley, Eric
energy levels, and any change in energy must be in the form of a quantum leap between two energy states spectroscopy at a quantum mechanical level, before moving on to look at the chemical processes present to the idea of the quantum nature of matter and radiation. Atoms and molecules can occupy certain discrete
Filter design for hybrid spin gates
Andreas Albrecht; Martin B. Plenio
2015-04-14T23:59:59.000Z
The impact of control sequences on the environmental coupling of a quantum system can be described in terms of a filter. Here we analyze how the coherent evolution of two interacting spins subject to periodic control pulses, at the example of a nitrogen vacancy center coupled to a nuclear spin, can be described in the filter framework in both the weak and the strong coupling limit. A universal functional dependence around the filter resonances then allows for tuning the coupling type and strength. Originally limited to small rotation angles, we show how the validity range of the filter description can be extended to the long time limit by time-sliced evolution sequences. Based on that insight, the construction of tunable, noise decoupled, conditional gates composed of alternating pulse sequences is proposed. In particular such an approach can lead to a significant improvement in fidelity as compared to a strictly periodic control sequence. Moreover we analyze the decoherence impact, the relation to the filter for classical noise known from dynamical decoupling sequences, and we outline how an alternating sequence can improve spin sensing protocols.
Stackhouse, S. (Michigan)
2008-10-08T23:59:59.000Z
The electronic configuration of iron impurities in lower-mantle minerals influences their physical properties, but it is not well constrained. New studies suggest that ferrous iron in silicate phases exists mainly in an intermediate spin state.
R. Annabestani; D. G. Cory; J. Emerson
2015-03-03T23:59:59.000Z
Any ensemble of quantum particles exhibits statistical fluctuations known as spin noise. Here, we provide a description of spin noise in the language of open quantum systems. The description unifies the signatures of spin noise under both strong and weak measurements. Further, the model accounts for arbitrary spin dynamics from an arbitrary initial state. In all cases we can find both the spin noise and its time correlation function.
Geometric phase for collinear conical intersections. I. Geometric phase angle and vector potentials
Li Xuan [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019 (United States); Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada); Brue, Daniel A.; Blandon, Juan D.; Parker, Gregory A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma 73019 (United States); Kendrick, Brian K. [Theoretical Division (T-1, MS B268), Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2011-02-14T23:59:59.000Z
We present a method for properly treating collinear conical intersections in triatomic systems. The general vector potential (gauge theory) approach for including the geometric phase effects associated with collinear conical intersections in hyperspherical coordinates is presented. The current study develops an introductory method in the treatment of collinear conical intersections by using the phase angle method. The geometric phase angle, {eta}, in terms of purely internal coordinates is derived using the example of a spin-aligned quartet lithium triatomic system. A numerical fit and thus an analytical form for the associated vector potentials are explicitly derived for this triatomic A{sub 3} system. The application of this methodology to AB{sub 2} and ABC systems is also discussed.
Manipulating topological states by imprinting non-collinear spin textures
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Streubel, Robert; Han, Luyang; Im, Mi -Young; Kronast, Florian; Rößler, Ulrich K.; Radu, Florin; Abrudan, Radu; Lin, Gungun; Schmidt, Oliver G.; Fischer, Peter; et al
2015-03-05T23:59:59.000Z
Topological magnetic states, such as chiral skyrmions, are of great scientific interest and show huge potential for novel spintronics applications, provided their topological charges can be fully controlled. So far skyrmionic textures have been observed in noncentrosymmetric crystalline materials with low symmetry and at low temperatures. We propose theoretically and demonstrate experimentally the design of spin textures with topological charge densities that can be tailored at ambient temperatures. Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can bemore »imprinted into the out-of-plane magnetised material. We observe distinct spin textures, e.g. vortices, magnetic swirls with tunable opening angle, donut states and skyrmion core configurations. We show that applying a small magnetic field, a reliable switching between topologically distinct textures can be achieved at remanence« less
Angle Coverage in Wireless Sensor Networks Chow Kit Yee
Tam, Vincent W. L.
. We study the scheduling problem to monitor a target continuously with full angle coverage. Several
Marie-Anne Bouchiat; Claude Bouchiat
2010-11-05T23:59:59.000Z
We derive the general formula giving the Berry phase for an arbitrary spin, having both magnetic-dipole and electric-quadrupole couplings with external time-dependent fields. We assume that the effective E and B fields remain orthogonal during the quantum cycles. This mild restriction has many advantages. It provides simple symmetries leading to selection rules and the Hamiltonian-parameter and density-matrix spaces coincide for S=1. This implies the identity of the Berry and Aharonov-Anandan phases, which is lost for S>1. We have found that new features of Berry phases emerge for integer spins>2. We provide explicit numerical results of Berry phases for S=2,3,4. We give a precise analysis of the non-adiabatic corrections. The accuracy for satisfying adiabaticity is greatly improved if one chooses for the time derivatives of the parameters a time-dependence having a Blackman pulse shape. This has the effect of taming the non-adiabatic oscillation corrections which could be generated by a linear ramping. For realistic experimental conditions, the non-adibatic corrections can be kept reversal of the angular velocity can be cancelled exactly if the quadrupole to dipole coupling ratio takes a "magic" value. The even ones are cancelled by subtraction of the phases relative to opposite velocities. As a possible application of the results of this paper we suggest a route to holonomic entanglement of N non-correlated 1/2-spins by performing adiabatic cycles governed by a Hamiltonian which is a non-linear function of the total spin operator S defined as the sum of the N spin operators. The case N=4 and Sz=1 is treated explicitly and maximum entanglement is achieved.
Negative nonlocal resistance in mesoscopic gold Hall bars : absence of giant spin Hall effect.
Mihajlovic, G.; Pearson, J. E.; Garcia, M. A.; Bader, S. D.; Hoffmann, A.; Univ. Complutense de Madrid
2009-01-01T23:59:59.000Z
We report the observation of negative nonlocal resistances in multiterminal mesoscopic gold Hall bar structures whose characteristic dimensions are larger than the electron mean-free path. Our results can only be partially explained by a classical diffusive model of the nonlocal transport, and are not consistent with a recently proposed model based on spin Hall effects. Instead, our analysis suggests that a quasiballistic transport mechanism is responsible for the observed negative nonlocal resistance. Based on the sensitivity of our measurements and the spin Hall effect model, we find an upper limit for the spin Hall angle in gold of 0.023 at 4.5 K.
SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments
Griffin, Robert G.
SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments Mikhail. Simulations of solid-state magic angle spinning (MAS) experiments can be particularly demanding both with complex pulse sequences and multi-spin systems in solids, SPINEVO- LUTION is a versatile and easy to use
SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments
Griffin, Robert G.
SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments Mikhail and dynamic information from the spectra. Simulations of solid-state magic angle spinning (MAS) experiments for the simulation of experiments with complex pulse sequences and multi-spin systems in solids, SPINEVO- LUTION
Wide Angle Effects in Galaxy Surveys
Yoo, Jaiyul
2013-01-01T23:59:59.000Z
Current and future galaxy surveys cover a large fraction of the entire sky with a significant redshift range, and the recent theoretical development shows that general relativistic effects are present in galaxy clustering on very large scales. This trend has renewed interest in the wide angle effect in galaxy clustering measurements, in which the distant-observer approximation is often adopted. Using the full wide-angle formula for computing the redshift-space correlation function, we show that compared to the sample variance, the deviation in the redshift-space correlation function from the simple Kaiser formula with the distant-observer approximation is negligible in the SDSS and is completely irrelevant in future galaxy surveys such as Euclid and the BigBOSS, if the theoretical prediction from the Kaiser formula is averaged over the survey volume and the non-uniform distribution of cosine angle between the line-of-sight and the pair separation directions is properly considered. We also find small correctio...
Miller, Jan D; Hupka, Jan; Aranowski, Robert
2012-11-20T23:59:59.000Z
A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.
Spinning superconducting electrovacuum soliton
Irina Dymnikova
2006-07-24T23:59:59.000Z
In nonlinear electrodynamics coupled to general relativity and satisfying the weak energy condition, a spherically symmetric electrically charged electrovacuum soliton has obligatory de Sitter center in which the electric field vanishes while the energy density of electromagnetic vacuum achieves its maximal value. De Sitter vacuum supplies a particle with the finite positive electromagnetic mass related to breaking of space-time symmetry from the de Sitter group in the origin. By the G\\"urses-G\\"ursey algorithm based on the Newman-Trautman technique it is transformed into a spinning electrovacuum soliton asymptotically Kerr-Newman for a distant observer. De Sitter center becomes de Sitter equatorial disk which has both perfect conductor and ideal diamagnetic properties. The interior de Sitter vacuum disk displays superconducting behavior within a single spinning soliton. This behavior found for an arbitrary nonlinear lagrangian ${\\cal L}(F)$, is generic for the class of regular spinning electrovacuum solutions describing both black holes and particle-like structures.
C. Schill; for the COMPASS collaboration
2012-01-02T23:59:59.000Z
The COMPASS experiment is a fixed target experiment at the CERN SPS using muon and hadron beams for the investigation of the spin structure of the nucleon and hadron spectroscopy. The main objective of the muon physics program is the study of the spin of the nucleon in terms of its constituents, quarks and gluons. COMPASS has accumulated data during 6 years scattering polarized muons off a longitudinally or a transversely polarized deuteron (6LiD) or proton (NH3) target. Results for the gluon polarization are obtained from longitudinal double spin cross section asymmetries using two different channels, open charm production and high transverse momentum hadron pairs, both proceeding through the photon-gluon fusion process. Also, the longitudinal spin structure functions of the proton and the deuteron were measured in parallel as well as the helicity distributions for the three lightest quark flavors. With a transversely polarized target, results were obtained with proton and deuteron targets for the Collins and Sivers asymmetries for charged hadrons as well as for identified kaons and pions. The Collins asymmetry is sensitive to the transverse spin structure of the nucleon, while the Sivers asymmetry reflects correlations between the quark transverse momentum and the nucleon spin. Recently, a new proposal for the COMPASS II experiment was accepted by the CERN SPS which includes two new topics: Exclusive reactions like DVCS and DVMP using the muon beam and a hydrogen target to study generalized parton distributions and Drell-Yan measurements using a pion beam and a polarized NH3 target to study transverse momentum dependent distributions.
Coherent spin mixing dynamics in thermal $^{87}$Rb spin-1 and spin-2 gases
He, Xiaodong; Li, Xiaoke; Wang, Fudong; Xu, Zhifang; Wang, Dajun
2015-01-01T23:59:59.000Z
We study the non-equilibrium coherent spin mixing dynamics in ferromagnetic spin-1 and antiferromagnetic spin-2 thermal gases of ultracold $^{87}$Rb atoms. Long lasting spin population oscillations with magnetic field dependent resonances are observed in both cases. Our observations are well reproduced by Boltzmann equations of the Wigner distribution function. Compared to the equation of motion of spinor Bose-Einstein condensates, the only difference here is a factor of two increase in the spin-dependent interaction, which is confirmed directly in the spin-2 case by measuring the relation between the oscillation amplitude and the sample's density.
Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics
Trukhanova, Mariya Iv
2015-01-01T23:59:59.000Z
We have developed the quantum hydrodynamic model that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics (QHD) equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin current wave dispersion. We have analyzed the limits of weak and strong magnetic fields.
Spin Precession and Quantum Vacuum
F. Kheirandish; M. Amooshahi
2005-09-18T23:59:59.000Z
The effect of quantum vacuum on spin precession is investigated. The radiation reaction is obtained and the time of spin flip (up state to down state) or spontaneous decay, is calculated.
Tensor analyzing powers in forward angle exclusive $\\pi$-meson photoproduction on deuteron
Loginov, A Y; Sidorov, A A; Stibunov, V N
2004-01-01T23:59:59.000Z
The target tensor analyzing powers of the process $\\gamma d -> \\pi^{-}pp$ had been studied in the plane wave impulse approximation, if both ejected protons are detected in coincidence and in the directions, symmetrical respect to the incoming photon momentum, being in the proton plane. The matrix elements of the studied reaction become essentially simple, if the magnitudes of the proton momenta p1 = p2 = p are equal. That proton kinematics keeps the ejected pion angle near zero, therefore the one body pion production operator does not include the spin-non-flip term. Moreover, the transition to the triplet, spatially antisymmetric final pp- state is strongly suppressed from the symmetrical deuteron S - state as well as matrix elements have a large dependence from the orientation of the deuteron spin. The values of the $T_{22}(\\vec p)$ component, calculated with three realistic deuteron wave functions in the proton momentum region p >= 350 MeV/c and proton polar angle theta >= 40 deg., differ one from another n...
Spin Transport in Semiconductor heterostructures
Domnita Catalina Marinescu
2011-02-22T23:59:59.000Z
The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional (2D) systems. The topics of interests ranged from the fundamental aspects of the electron-electron interactions, to collective spin and charge density excitations and spin transport in the presence of the spin-orbit coupling. The common denominator of these subjects is the impact at the macroscopic scale of the spin-dependent electron-electron interaction, which plays a much more subtle role than in unpolarized electron systems. Our calculations of several measurable parameters, such as the excitation frequencies of magneto-plasma modes, the spin mass, and the spin transresistivity, propose realistic theoretical estimates of the opposite-spin many-body effects, in particular opposite-spin correlations, that can be directly connected with experimental measurements.
TRANSVERSITY SINGLE SPIN ASYMMETRIES.
BOER,D.
2001-04-27T23:59:59.000Z
The theoretical aspects of two leading twist transversity single spin asymmetries, one arising from the Collins effect and one from the interference fragmentation functions, are reviewed. Issues of factorization, evolution and Sudakov factors for the relevant observables are discussed. These theoretical considerations pinpoint the most realistic scenarios towards measurements of transversity.
Gerlach, Ulrich
spin at each event. A unique and natural law of parallel transport of quantum states between different mechanical line of reasoning leads to the heuristic con* *clusion that gravitation is to be identified AND ITS GAUGE GEOMETRY The line of reasoning which lies at the base of Einstein's gravitation the
Gluonic Spin Contribution to Proton Spin at NLO
Casey, Andrew [CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide SA 5005 (Australia)
2011-05-24T23:59:59.000Z
In 1988, when the EMC results showed that the quarks had a much smaller contribution to the spin of the proton than previously thought, the 'Proton Spin Crisis' began. Since then, considerable effort has been directed into discovering the main contributors to proton spin and how much each contributes. One such contributor is the gluonic spin component. QCD NLO evolution equations are combined with boundary conditions obtained from heavy quark decoupling expressions to evolve the equations from infinity to the mass of the charm quark in order to determine the gluonic spin contribution.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary Moniz9Morgan ManagingW.tepidumAngle X-ray Scattering
angle diffractometer sans: Topics by E-print Network
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14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 SANS -Small Angle Neutron Scattering Tcnica de difrao Chemistry Websites Summary: SANS - Small Angle Neutron...
angle neutron diffractometer: Topics by E-print Network
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steel Low alloy ferritic steel Alloy 52 L0 L d0 d Bandara, Arosha 6 SANS -Small Angle Neutron Scattering Tcnica de difrao Chemistry Websites Summary: SANS - Small Angle Neutron...
RHIC spin flipper commissioning results
Bai M.; Roser, T.; Dawson, C.; Kewisch, J.; Makdisi, Y.; Oddo, P.; Pai, C.; Pile, P.
2012-05-20T23:59:59.000Z
The five AC dipole RHIC spin flipper design in the RHIC Blue ring was first tested during the RHIC 2012 polarized proton operation. The advantage of this design is to eliminate the vertical coherent betatron oscillations outside the spin flipper. The closure of each ac dipole vertical bump was measured with orbital response as well as spin. The effect of the rotating field on the spin motion by the spin flipper was also confirmed by measuring the suppressed resonance at Q{sub s} = 1 - Q{sub osc}.
Small Angle X-ray Scattering (SAXS) Laboratory Learning Experiences
Meagher, Mary
.A. & Svergun D.I. (1987). Structure Analysis by Small-Angle X-Ray and Neutron Scattering. NY: Plenum PressSmall Angle X-ray Scattering (SAXS) Laboratory Learning Experiences o - Use of small angle X-ray scattering instrumentation o - Programs that you will use SAXS (BRUKER AXS) PRIMUS (Konarev, Volkov, Koch
Classification of two dimensional fixed sun angle solar sail trajectories
Roberts, Mark
Classification of two dimensional fixed sun angle solar sail trajectories Stephen Wokes, Phil heliocentric trajectories for fixed sun angle solar sails are examined. The objective of this work (lightness factor) and Sun angle this phase space shows all possible solar sail trajectories. This phase
Directional dark matter by polar angle direct detection and application of columnar recombination
Jin Li
2015-03-25T23:59:59.000Z
We report a systematic study on the directional sensitivity of a direct dark matter detector that detects the polar angle of a recoiling nucleus. A WIMP-mass independent method is used to obtain the sensitivity of a general detector in an isothermal galactic dark matter halo. By using two-dimensional distributions of energy and polar angle, a detector without head-tail information with 6.3 times the statistics is found to achieve the same performance level as a full three-dimensional tracking dark matter detector. Optimum operation orientations are obtained for various experimental configurations, with detectors that are space- or Earth-fixed, have head-tail capability or not, and use energy information or not. Earth-fixed detectors are found to have best sensitivity when the polar axis is oriented at a 45 degree angle from the Earth's pole. The WIMP-mass dependence of the performance of a detector with a 3 keV energy threshold that uses xenon as target material is reported. We apply realistic experimental resolutions and thresholds for a columnar recombination detector that detects two channel recombination and ionization processes from gaseous xenon. We find that with a $5\\times 10^{-46} \\mathrm{cm}^2$ spin-independent WIMP-nucleon cross-section and a 30 GeV WIMP, a $636$ kg$\\cdot$year's exposure with a columnar recombination detector can make a three sigma discovery of directional WIMPs in the isothermal galactic dark matter halo.
Cédric Lorcé
2014-09-16T23:59:59.000Z
The proton spin puzzle issue focused the attention on the parton spin and orbital angular momentum contributions to the proton spin. However, a complete characterization of the proton spin structure requires also the knowledge of the parton spin-orbit correlation. We showed that this quantity can be expressed in terms of moments of measurable parton distributions. Using the available phenomenological information about the valence quarks, we concluded that this correlation is negative, meaning that the valence quark spin and kinetic orbital angular momentum are, in average, opposite. The quark spin-orbit correlation can also be expressed more intuitively in terms of relativistic phase-space distributions, which can be seen as the mother distributions of the standard generalized and transverse-momentum dependent parton distributions. We present here for the first time some examples of the general multipole decomposition of these phase-space distributions.
Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.
2015-03-01T23:59:59.000Z
The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore »before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less
Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhou, Xiaoli [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Kollias, Pavlos [McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences; Lewis, Ernie R. [Brookhaven National Lab., Upton, NY (United States). Biological, Environmental, and Climate Sciences Dept.
2015-03-01T23:59:59.000Z
The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)
G. Salesi
2009-06-23T23:59:59.000Z
Starting from the Pauli current we obtain the decomposition of the non-relativistic local velocity in two parts: one parallel and the other orthogonal to the momentum. The former is recognized to be the ``classical'' part, that is the velocity of the center-of-mass, and the latter the ``quantum'' one, that is the velocity of the motion in the center-of-mass frame (namely, the internal ``spin motion'' or {\\em Zitterbewegung}). Inserting the complete expression of the velocity into the kinetic energy term of the classical non-relativistic (i.e., Newtonian) Lagrangian, we straightforwardly derive the so-called ``quantum potential'' associated to the Madelung fluid. In such a way, the quantum mechanical behaviour of particles appears to be strictly correlated to the existence of spin and Zitterbewegung.
MAGIC Collaboration; Florian Goebel; Hendrik Bartko; Emiliano Carmona; Nicola Galante; Tobias Jogler; Razmik Mirzoyan; Jose Antonio Coarasa; Masahiro Teshima
2007-09-14T23:59:59.000Z
In February 2007 the MAGIC Air Cherenkov Telescope for gamma ray astronomy was fully upgraded with a fast 2 GSamples/s digitization system. The upgraded readout system uses a novel fiber-optic multiplexing technique. It consists of 10-bit 2 GSamples/s FADCs to digitize 16 channels consecutively and optical fibers to delay the analog signals. A distributed data acquisition system using GBit Ethernet and FiberChannel technology allows to read out the 100 kByte events with a continuous rate of up to 1 kHz.
Masahiro Teshima; Elisa Prandini; Rudolf Bock; Manel Errando; Daniel Kranich; Pratik Majumdar; Daniel Mazin; Elina Lindfors; Eckart Lorenz; Mose Mariotti; Villi Scalzotto; Robert Wagner
2007-09-10T23:59:59.000Z
The quasar 3C 279 is one of the best-studied flat spectrum radio quasars. It is located at a comparatively large redshift of z=0.536: E>100 GeV observations of such distant sources were until recently impossible both due to the expected steep energy spectrum and the expected attenuation of the gamma-rays by the extragalactic background light. Here we present results on the observation of 3C 279 with the MAGIC telescope in early 2006. We report the detection of a significant very high energy gamma-ray signal in the MAGIC energy range on the observation night of 2006 February 23.
M. Rosenbusch; P. Ascher; D. Atanasov; C. Barbieri; D. Beck; K. Blaum; Ch. Borgmann; M. Breitenfeldt; R. B. Cakirli; A. Cipollone; S. George; F. Herfurth; M. Kowalska; S. Kreim; D. Lunney; V. Manea; P. Navrátil; D. Neidherr; L. Schweikhard; V. Somà; J. Stanja; F. Wienholtz; R. N. Wolf; K. Zuber
2015-06-01T23:59:59.000Z
The recently confirmed neutron-shell closure at N = 32 has been investigated for the first time below the magic proton number Z = 20 with mass measurements of the exotic isotopes 52,53K, the latter being the shortest-lived nuclide investigated at the online mass spectrometer ISOLTRAP. The resulting two-neutron separation energies reveal a 3 MeV shell gap at N = 32, slightly lower than for 52Ca, highlighting the doubly-magic nature of this nuclide. Skyrme-Hartree-Fock-Boguliubov and ab initio Gorkov-Green function calculations are challenged by the new measurements but reproduce qualitatively the observed shell effect.
Putting the Spin on Graphite: Observing the Spins of Impurity...
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the Spins of Impurity Atoms Align Friday, February 28, 2014 The existence of magnetism in graphite is a very intriguing subject. The possibility to exploit the magnetic...
Forward collisions and spin effects in evaluating amplitudes
Buttimore, N. H. [Trinity College Dublin (Ireland)
2011-07-15T23:59:59.000Z
Total cross sections and the phases of forward collision amplitudes form part of the early studies when a new energy window becomes available as is provided by the Large Hadron Collider. Enhancement of the forward elastic differential cross section above that expected from estimates of dispersion and optical theorem values may result from the presence of hadronic spin dependence in addition to effects induced by vacuum polarization contributions to the photon propagator. The elastic scattering of protons and ions at small angles is important in the evaluation of the luminosities of the corresponding incident beams and invites detailed examination. Polarization measurements taken at a number of high energies have yielded information on the extent of spin effects in hadronic scattering, particularly at the low momentum transfers related to diffraction.
Studies of spin-orbit correlations at JLAB
Mher Aghasyan, Harut Avakian
2011-05-01T23:59:59.000Z
Studies of single spin asymmetries for pion electroproduction in semi-inclusive deep-inelastic scattering are presented using the polarized \\sim6 GeV electrons from at the Thomas Jefferson National Accelerator Facility (JLab) and the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) with the Inner Calorimeter. The cross section versus the azimuthal angle {\\phi}_h of the produced neutral pion has a substantial sin {\\phi}_h amplitude. The dependence of this amplitude on Bjorken x_B and on the pion transverse momentum is extracted and compared with published data.
Studies of spin-orbit correlations at JLAB
Aghasyan, Mher
2011-01-01T23:59:59.000Z
Studies of single spin asymmetries for pion electroproduction in semi-inclusive deep-inelastic scattering are presented using the polarized \\sim6 GeV electrons from at the Thomas Jefferson National Accelerator Facility (JLab) and the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) with the Inner Calorimeter. The cross section versus the azimuthal angle {\\phi}_h of the produced neutral pion has a substantial sin {\\phi}_h amplitude. The dependence of this amplitude on Bjorken x_B and on the pion transverse momentum is extracted and compared with published data.
Studies of spin-orbit correlations at JLAB
Mher Aghasyan; Harut Avakian
2011-03-16T23:59:59.000Z
Studies of single spin asymmetries for pion electroproduction in semi-inclusive deep-inelastic scattering are presented using the polarized \\sim6 GeV electrons from at the Thomas Jefferson National Accelerator Facility (JLab) and the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) with the Inner Calorimeter. The cross section versus the azimuthal angle {\\phi}_h of the produced neutral pion has a substantial sin {\\phi}_h amplitude. The dependence of this amplitude on Bjorken x_B and on the pion transverse momentum is extracted and compared with published data.
Heat generation by electronic current in a quantum dot spin-valve
Chi, Feng [School of Physical Science and Technology, Inner Mongolia University, Huhehaote 010023 (China); College of Engineering, Bohai University, Jinzhou 121013 (China); Sun, Lian-Liang [College of Science, North China University of Technology, Beijing 100041 (China); Guo, Yu [College of Engineering, Bohai University, Jinzhou 121013 (China)
2014-10-28T23:59:59.000Z
Electric-current-induced heat generation in an interacting single-level quantum dot connected to ferromagnetic leads with noncollinear magnetizations is theoretically investigated. We find that when the two leads' spin polarization rates are identical and much smaller than unit, the magnitude of the heat generation is almost monotonously enhanced as the angle between the leads' magnetic moments is varied from zero to ?, while the magnitude of the electric current is continuously suppressed. Moreover, the properties of the heat generation depend on the lead's spin polarization rate in different ways when the angle is varied. If at least one of the leads' spin polarization rate approaches to unit, the spin-valve effect of the heat generation is identical to that of the electric current. Now the previously found negative differential of the heat generation disappears when the angle approaches to ?. As compared to the current, the heat generation is more sensitive to the system's asymmetry when one of the electrodes is half-metallic in noncollinear configurations.
Feedback control of spin systems
Claudio Altafini
2006-01-03T23:59:59.000Z
The feedback stabilization problem for ensembles of coupled spin 1/2 systems is discussed from a control theoretic perspective. The noninvasive nature of the bulk measurement allows for a fully unitary and deterministic closed loop. The Lyapunov-based feedback design presented does not require spins that are selectively addressable. With this method, it is possible to obtain control inputs also for difficult tasks, like suppressing undesired couplings in identical spin systems.
Asymptotics of Relativistic Spin Networks
John W Barrett; Christopher M Steele
2003-01-31T23:59:59.000Z
The stationary phase technique is used to calculate asymptotic formulae for SO(4) Relativistic Spin Networks. For the tetrahedral spin network this gives the square of the Ponzano-Regge asymptotic formula for the SU(2) 6j symbol. For the 4-simplex (10j-symbol) the asymptotic formula is compared with numerical calculations of the Spin Network evaluation. Finally we discuss the asymptotics of the SO(3,1) 10j-symbol.
Ballistic spin-dependent transport of Rashba rings with multi-leads
Huang Guangyao [State Key Laboratory of Optoelectronic Material and Technology and School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Liang Shidong, E-mail: stslsd@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Material and Technology and School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)
2011-05-15T23:59:59.000Z
Research Highlights: > Transmission coefficients of each outgoing lead in multi-lead mesoscopic Rashba rings. > Spin polarizations of each outgoing lead in multi-lead mesoscopic Rashba rings. > Resonant and antiresonant conditions of spin polarization in multi-lead Rashba rings. > Symmetries of conductance and spin polarization of symmetric multi-lead Rashba rings. - Abstract: Using the Landauer-Buettiker formula with the transfer matrix technique, we develop a formalism of the ballistic spin-dependent electron transport in the multi-lead Rashba rings. We give analytic formulas of the total conductance G{sub j}, spin-{sigma} conductance g{sub j}{sup {sigma}} and spin polarization P{sub j} of each outgoing lead j, and their resonant and antiresonant conditions. Analytic studying with numerical investigating Rashba rings with several symmetric and asymmetric leads, we find that G{sub j}, g{sub j}{sup {sigma}} and P{sub j} oscillate with the incoming electron energy and the spin-orbit interaction (SOI) strength, and their antiresonances depend on the incoming electron energy, the SOI strength and the outgoing-lead angle with the incoming lead. For the symmetric-lead rings, G{sub j}, g{sub j}{sup {sigma}} and P{sub j} have some symmetries, G{sub j}=G{sub N-j},g{sub j}{sup {sigma}}=g{sub N-j}{sup -{sigma}}, and P{sub j} = -P{sub N-j} for symmetric leads, j and N - j, where the angles between the symmetric outgoing leads j and N - j and the incoming lead are {gamma}{sub N-j} = 2{pi} - {gamma}{sub j}. The spin polarization of the outgoing lead with {gamma}{sub j} = {pi} is exactly zero for even-N-symmetric-lead rings. These symmetries originate from the lead symmetry and time reversal invariance. For asymmetry-lead rings these symmetries vanish.
Heterostructure unipolar spin transistors M. E. Flatta
Flatte, Michael E.
carriers on one side of the device are spin-down spin-up electrons and on the other side of the device semiconductor electronics and spin-based unipolar electronics by considering unipolar spin transistors electrons to the collector limits the performance of "homojunction" unipolar spin transistors, in which
Dosimetric Comparison of Manual and Beam Angle Optimization of Gantry Angles in IMRT
Srivastava, Shiv P. [Department of Radiation Oncology, Reid Hospital and Health Care Services, Richmond, IN (United States); Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Das, Indra J., E-mail: idas@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Kumar, Arvind [Department of Radiation Oncology, Reid Hospital and Health Care Services, Richmond, IN (United States); Johnstone, Peter A.S. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States)
2011-10-01T23:59:59.000Z
Dosimetric comparison of manual beam angle selection (MBS) and beam angle optimization (BAO) for IMRT plans is investigated retrospectively for 15 head and neck and prostate patients. The head and neck and prostate had planning target volumes (PTVs) ranging between 96.0 and 319.9 cm{sup 3} and 153.6 and 321.3 cm{sup 3}, whereas OAR ranged between 8.3 and 47.8 cm{sup 3} and 68.3 and 469.2 cm{sup 3}, respectively. In MBS, a standard coplanar 7-9 fields equally spaced gantry angles were used. In BAO, the selection of gantry angle was optimized by the algorithm for the same number of beams. The optimization and dose-volume constraints were kept the same for both techniques. Treatment planning was performed on the Eclipse treatment planning system. Our results showed that the dose-volume histogram for PTV are nearly identical in both techniques but BAO provided superior sparing of the organs at risk compared with the MBS. Also, MBS produced statistically significant higher monitor units (MU) and segments than the BAO; 13.1 {+-} 6.6% (p = 0.012) and 10.4 {+-} 13.6% (p = 0.140), and 14.6 {+-} 5.6% (p = 1.003E-5) and 12.6 {+-} 7.4% (p = 0.76E-3) for head and neck and prostate cases, respectively. The reduction in MU translates into the reduction in total body and integral dose. It is concluded that BAO provides advantage over MBS for most intenisty-modulated radiation therapy cases.
Lipscombe, O. J. [University of Tennessee, Knoxville (UTK); Chen, G. F. [The Institute of Physics, Chinese Academy of Sciences; Fang, Chen [Purdue University; Perring, T. G. [ISIS Facility, Rutherford Appleton Laboratory; Abernathy, Douglas L [ORNL; Christianson, Andrew D [ORNL; Egami, Takeshi [ORNL; Wang, Nanlin [The Institute of Physics, Chinese Academy of Sciences; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)
2011-01-01T23:59:59.000Z
We use neutron scattering to show that spin waves in the iron chalcogenide Fe{sub 1.05}Te display novel dispersion clearly different from both the first principles density functional calculations and recent observations in the related iron pnictide CaFe{sub 2}As{sub 2}. By fitting to a Heisenberg Hamiltonian, we find that although the nearest-neighbor exchange couplings in the two systems are quite different, their next-nearest-neighbor (NNN) couplings are similar. This suggests that superconductivity in the pnictides and chalcogenides share a common magnetic origin that is intimately associated with the NNN magnetic coupling between the irons.
Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect
Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenería, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)] [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)
2013-12-09T23:59:59.000Z
The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ?1.2 nm at room temperature and ?1.6 nm at 8 K.
Spin-rotation coupling in compound spin objects
G. Lambiase; G. Papini
2013-01-31T23:59:59.000Z
We generalize spin-rotation coupling to compound spin systems. In the case of muons bound to nuclei in a storage ring the decay process acquires a modulation. Typical frequencies for $Z/A\\sim 1/2$ are $\\sim 3\\times 10^6$Hz, a factor 10 higher than the modulation observed in $g-2$ experiments.
Industries and Spin-offs 485 and Spin-offs
-based Rockwell allocated work to rivals in other parts of the country. Grumman of Long Island, New York, whichIndustries and Spin-offs 485 Industries and Spin-offs #12;In the late 1960s, many of America Richard Nixon's approval of the Space Shuttle Program came along just in time for an industry whose future
Emission angle distribution and flavor transformation of supernova neutrinos
Wei Liao
2009-06-28T23:59:59.000Z
Using moment equations we analyze collective flavor transformation of supernova neutrinos. We study the convergence of moment equations and find that numerical results using a few moment converge quite fast. We study effects of emission angle distribution of neutrinos on neutrino sphere. We study scaling law of the amplitude of neutrino self-interaction Hamiltonian and find that it depends on model of emission angle distribution of neutrinos. Dependence of neutrino oscillation on different models of emission angle distribution is studied.
Unique determination of the -CN group tilt angle in Langmuir...
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angle and phase. Abstract: The relative phase and amplitude ratio between the ssp and ppp polarization combinations of the vibrational sum-frequency generation (SFG) response...
ANGLE-RESOLVED PHOTOEMISSION STUDIES OF Ag, Au, AND Pt
Davis, R.F.
2010-01-01T23:59:59.000Z
under Contract W-7405-ENG-48 ANGLE-RESOLVED PHOTOEMISSIONEnergy under Contract No. W-7405-Eng-48. It was performed at
angle light scattering: Topics by E-print Network
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Biological tissues tend Kim, Arnold D. 11 Static light scattering and small-angle neutron scattering study on aggregated recombinant gelatin in aqueous solution University...
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report gives selected examples illustrating the use of specific techni- cal 2 Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions...
angling commercial: Topics by E-print Network
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chronic open angle glaucoma by UK community optometrists. (Unpublished Doctoral thesis, City University London) City Research Online Original citation: Myint, Joy (2013). A study...
Local Uniqueness for the Fixed Energy Fixed Angle Inverse Problem ...
Abstract. We prove local uniqueness for the inverse problem in obstacle scattering at a fixed energy and fixed incident angle. We consider the inverse problem of ...
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bend angle Physics Websites Summary: mercury water flow through a bend pipe into the air environment Medium Reynolds Number Inner DiameterSimulation for pipes with changing bend...
The new small-angle diffractometer SAND at IPNS
Crawford, R.K.; Thiyagarajan, P.; Epperson, J.E.; Trouw, F.; Kleb, R.; Wozniak, D.; Leach, D.
1995-12-31T23:59:59.000Z
A new small-angle neutron diffractometer SAND is undergoing commissioning at IPNS pulsed source. This paper provides details of the design and expected performance of this instrument.
Paris-Sud XI, UniversitÃ© de
Future recovery of acidified lakes in southern Norway predicted by the MAGIC model 467 Hydrology and Earth System Sciences, 7(4), 467483 (2003) Â© EGU Future recovery of acidified lakes in southern Norway.O. Box 173 KjelsÃ¥s, N-0411 Oslo, Norway 2 Department of Environmental Sciences, University of Virginia
Spin noise spectroscopy of ZnO
Horn, H.; Berski, F.; Hübner, J.; Oestreich, M. [Institute for Solid State Physics, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover (Germany); Balocchi, A.; Marie, X. [INSA-CNRS-UPS, LPCNO, Université de Toulouse, 135 Av. de Rangueil, 31077 Toulouse (France); Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A. [Institute of Semiconductor Technology, Technische Universität Braunschweig, Hans-Sommer-Straße 66, 38106 Braunschweig (Germany)
2013-12-04T23:59:59.000Z
We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.
QCD Spin Physics: Theoretical Overview
Vogelsang,W.
2008-11-09T23:59:59.000Z
We give an overview of some of the current activities and results in QCD spin physics. We focus on the helicity structure of the nucleon, where we highlight the results of a recent first global analysis of the helicity parton distributions, and on single-transverse spin asymmetries.
S. Dhar; B. Basu; Subir Ghosh
2007-06-27T23:59:59.000Z
We explain the intrinsic spin Hall effect from generic anyon dynamics in the presence of external electromagnetic field. The free anyon is represented as a spinning particle with an underlying non-commutative configuration space. The Berry curvature plays a major role in the analysis.
A hidden BFKL / XXX s = -1/2 spin chain mapping
Alberto Romagnoni; Agustin Sabio Vera
2011-11-19T23:59:59.000Z
A new mapping between the BFKL equation and Beisert's representation of the XXX Heisenberg ferromagnet with spin s = - 1/2 is given. The action of the Hamiltonian operator of a spin chain with SL(2) invariance on a symmetric double copy of a harmonic oscillator excited state is shown to be identical to the action of the BFKL Hamiltonian on the gluon Green function for the azimuthal-angle averaged forward scattering case. A natural mapping between the gluon Green function, discretized in virtuality space, and the double harmonic oscillator excited state emerges.
A hidden BFKL / XXX s = -1/2 spin chain mapping
Romagnoni, Alberto
2011-01-01T23:59:59.000Z
A new mapping between the BFKL equation and Beisert's representation of the XXX Heisenberg ferromagnet with spin s = - 1/2 is given. The action of the Hamiltonian operator of a spin chain with SL(2) invariance on a symmetric double copy of a harmonic oscillator excited state is shown to be identical to the action of the BFKL Hamiltonian on the gluon Green function for the azimuthal-angle averaged forward scattering case. A natural mapping between the gluon Green function, discretized in virtuality space, and the double harmonic oscillator excited state emerges.
Flipping Photoelectron Spins in Topological Insulators
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Flipping Photoelectron Spins in Topological Insulators Flipping Photoelectron Spins in Topological Insulators Print Tuesday, 23 April 2013 10:00 Inherently strange crystalline...
Superconducting magnetic Wollaston prism for neutron spin encoding
Li, F., E-mail: fankli@indiana.edu; Parnell, S. R.; Wang, T.; Baxter, D. V. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States)] [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Hamilton, W. A. [Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)] [Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Maranville, B. B. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)] [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Semerad, R. [Ceraco Ceramic Coating GmbH, Ismaning 85737 (Germany)] [Ceraco Ceramic Coating GmbH, Ismaning 85737 (Germany); Cremer, J. T. [Adelphi Technology Inc., Redwood City, California 94063 (United States)] [Adelphi Technology Inc., Redwood City, California 94063 (United States); Pynn, R. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States) [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)
2014-05-15T23:59:59.000Z
A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ?30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ?98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 ?m. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.
Steiner Minimal Trees, Twist Angles, and the Protein Folding Problem
Smith, J. MacGregor
Steiner Minimal Trees, Twist Angles, and the Protein Folding Problem J. MacGregor Smith, Yunho Jang. These properties should be ultimately useful in the ab ini- tio protein folding prediction. Proteins 2007;66:889 902. VVC 2006 Wiley-Liss, Inc. Key words: Steiner trees; twist angles; protein fold- ing; side chain
Parity-violating neutron spin rotation in hydrogen and deuterium
Harald W. Griesshammer; Matthias R. Schindler; Roxanne P. Springer
2012-01-23T23:59:59.000Z
We calculate the (parity-violating) spin rotation angle of a polarized neutron beam through hydrogen and deuterium targets, using pionless effective field theory up to next-to-leading order. Our result is part of a program to obtain the five leading independent low-energy parameters that characterize hadronic parity-violation from few-body observables in one systematic and consistent framework. The two spin-rotation angles provide independent constraints on these parameters. Using naive dimensional analysis to estimate the typical size of the couplings, we expect the signal for standard target densities to be 10^-7 to 10^-6 rad/m for both hydrogen and deuterium targets. We find no indication that the nd observable is enhanced compared to the np one. All results are properly renormalized. An estimate of the numerical and systematic uncertainties of our calculations indicates excellent convergence. An appendix contains the relevant partial-wave projectors of the three-nucleon system.
Coarse graining methods for spin net and spin foam models
Bianca Dittrich; Frank C. Eckert; Mercedes Martin-Benito
2011-09-22T23:59:59.000Z
We undertake first steps in making a class of discrete models of quantum gravity, spin foams, accessible to a large scale analysis by numerical and computational methods. In particular, we apply Migdal-Kadanoff and Tensor Network Renormalization schemes to spin net and spin foam models based on finite Abelian groups and introduce `cutoff models' to probe the fate of gauge symmetries under various such approximated renormalization group flows. For the Tensor Network Renormalization analysis, a new Gauss constraint preserving algorithm is introduced to improve numerical stability and aid physical interpretation. We also describe the fixed point structure and establish an equivalence of certain models.
Very high energy gamma-ray follow-up observations of novae and dwarf novae with the MAGIC telescopes
Sitarek, J; Lopez-Coto, R; Wilhelmi, E de Ona; Desiante, R; Longo, F; Hays, E
2015-01-01T23:59:59.000Z
In the last few years the Fermi -LAT instrument has detected GeV gamma-ray emission from a few novae. Such GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. It is expected that hadrons can be accelerated in the same conditions, but reaching much higher energies. They can produce a second component in the gamma-ray spectrum at TeV energies. We performed follow-up observations of selected novae and dwarf novae in a search of the second component in the gamma-ray spectrum. This can shed light on the acceleration process of leptons and hadrons in nova explosions. We have performed observations with the MAGIC telescopes of 3 sources, a symbiotic nova YY Her, a dwarf nova ASASSN-13ax and a classical nova V339 Del shortly after their outbursts.
Pavel A. Andreev
2014-05-04T23:59:59.000Z
Quantum hydrodynamic (QHD) model of charged spin-1/2 particles contains physical quantities defined for all particles of a species including particles with spin-up and with spin-down. Different population of states with different spin direction is included in the spin density (magnetization). In this paper we derive a QHD model, which separately describes spin-up electrons and spin-down electrons. Hence we consider electrons with different projection of spin on the preferable direction as two different species of particles. We show that numbers of particles with different spin direction do not conserve. Hence the continuity equations contain sources of particles. These sources are caused by the interactions of spins with magnetic field. Terms of similar nature arise in the Euler equation. We have that z-projection of the spin density is no longer an independent variable. It is proportional to difference between concentrations of electrons with spin-up and electrons with spin-down. In terms of new model we consider propagation of waves in magnetized plasmas of degenerate electrons and motionless ions. We show that new form of QHD equations gives all solutions obtained from traditional form of QHD equations with no distinguish of spin-up and spin-down states. But it also reveals a sound-like solution we call the spin-electron acoustic wave. Coincidence of most solutions is expected since we started derivation with the same basic equation.
Topologically Massive Spin-1 Particles and Spin-Dependent Potentials
F. A. Gomes Ferreira; P. C. Malta; L. P. R. Ospedal; J. A. Helayël-Neto
2015-04-27T23:59:59.000Z
We investigate the role played by particular field representations of an intermediate massive spin-1 boson in the context of spin-dependent interparticle potentials between fermionic sources in the limit of low momentum transfer. The comparison between the well-known case of the Proca field and that of an exchanged spin-1 boson (with gauge-invariant mass) described by a 2-form potential mixed with a 4-vector gauge field is established in order to pursue an analysis of spin- as well as velocity-dependent profiles of the interparticle potentials. We discuss possible applications and derive an upper bound on the product of vector and pseudo-tensor coupling constants.
Spin Contamination in Inorganic Chemistry Calculations
Schlegel, H. Bernhard
R EVISED PAG E PR O O FS ia617 Spin Contamination in Inorganic Chemistry Calculations Jason L . In such cases, 0 is said to be spin contaminated owing to incorporation of higher spin state character of IronSulfur ia618 Clusters). It is important to note that while spin-contaminated and broken
RESEARCH PLAN FOR SPIN PHYSICS AT RHIC.
AIDALA, C.; BUNCE, G.; ET AL.
2005-02-01T23:59:59.000Z
In this report we present the research plan for the RHIC spin program. The report covers (1) the science of the RHIC spin program in a world-wide context; (2) the collider performance requirements for the RHIC spin program; (3) the detector upgrades required, including timelines; (4) time evolution of the spin program.
{gamma} spectroscopy around doubly magic {sup 48}Ca by heavy-ion transfer reactions
Leoni, Silvia [Department of Physics, University of Milano and INFN, Milano (Italy)
2012-10-20T23:59:59.000Z
{gamma} spectroscopy of neutron-rich nuclei around {sup 48}Ca is performed by the heavy-ion transfer reaction {sup 48}Ca on {sup 64}Ni at 282 MeV, with the PRISMA-CLARA setup at Legnaro Laboratory. Angular distributions, polarizations and lifetimes analysis probe spin and parities of several excited states, shading lights on their configuration. In the one neutron transfer channels, {sup 49}Ca and {sup 47}Ca, states arising by coupling a single particle to the 3{sup -} phonon of {sup 48}Ca are observed, showing the robustness of nuclear collectivity in rather light systems. The work demonstrates the feasibility of complete in-beam {gamma}-spectroscopy with heavy-ion transfer reactions and provides a method that can be further exploited in the future with heavy targets and radioactive beams.
Spin-dependent boundary resistance in the lateral spin-valve structure T. Kimura,a)
Otani, Yoshichika
Spin-dependent boundary resistance in the lateral spin-valve structure T. Kimura,a) J. Hamrle spin-valve signal without any spurious magnetoresistive signal in a lateral spin-valve structure consisting of Cu/Ni-Fe ohmic junction using local current injection. The obtained spin-valve signal is much
Large Spin Accumulation in a Permalloy-Silver Lateral Spin Valve T. Kimura and Y. Otani
Otani, Yoshichika
Large Spin Accumulation in a Permalloy-Silver Lateral Spin Valve T. Kimura and Y. Otani Institute accumulation due to the electrical spin injection has been observed in Permalloy-silver lateral spin-valve structures. The observed resistance change is the largest among the reported metallic lateral spin valves
Spin-current-induced dynamics in ferromagnetic nanopillars of lateral spin-valve structures
Otani, Yoshichika
Spin-current-induced dynamics in ferromagnetic nanopillars of lateral spin-valve structures J 4 February 2009 Under electrical injection, spin accumulation occurs in lateral spin valves in a lateral spin valve while simultaneously sweeping an external magnetic field. We observe changes
Modeling of diffusion of injected electron spins in spin-orbit coupled microchannels
Zarbo, Liviu P.; Sinova, Jairo; Knezevic, I.; Wunderlich, J.; Jungwirth, T.
2010-01-01T23:59:59.000Z
We report on a theoretical study of spin dynamics of an ensemble of spin-polarized electrons injected in a diffusive microchannel with linear Rashba and Dresselhaus spin-orbit coupling. We explore the dependence of the spin-precession and spin...
Time evolution of a single spin inhomogeneously coupled to an interacting spin environment
Kais, Sabre
Time evolution of a single spin inhomogeneously coupled to an interacting spin environment Zhen to an environment of interacting spin bath modeled by the XY Hamiltonian. By evaluating the spin correlator the spins in the environment J. The decoherence time varies significantly based on the relative coupling
Quantum correlations in spin models
Zhang Guofeng, E-mail: gf1978zhang@buaa.edu.cn [Department of Physics, School of Physics and Nuclear Energy Engineering, Beihang University, Xueyuan Road No. 37, Beijing 100191 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Fan Heng; Ji Ailing [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Jiang Zhaotan [Department of Physics, Beijing Institute of Technology, Beijing 100081 (China); Abliz, Ahmad [School of Mathematics, Physics and Informatics, Xinjiang Normal University, Urumchi 830054 (China); Liu Wuming [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2011-10-15T23:59:59.000Z
Bell nonlocality, entanglement and nonclassical correlations are different aspects of quantum correlations for a given state. There are many methods to measure nonclassical correlations. In this paper, nonclassical correlations in two-qubit spin models are measured by the use of measurement-induced disturbance (MID) [S. Luo, Phys. Rev. A 77 (2008) 022301] and geometric measure of quantum discord (GQD) [B. Dakic, V. Vedral, C. Brukner, Phys. Rev. Lett. 105 (2010) 190502]. Their dependences on external magnetic field, spin-spin coupling, and the Dzyaloshinskii-Moriya (DM) interaction are presented in detail. We also compare Bell nonlocality, entanglement measured by concurrence, MID and GQD and illustrate their different characteristics. - Highlights: > Various quantum correlations in spin models are investigated. > Nonclassical correlations are measured by measurement-induced disturbance and Geometric measure of quantum discord. > Also, we investigate Bell nonlocality and concurrence. > We compare these quantum quantities and illustrate their different characteristics.
Spin Filtering in Storage Rings
N. N. Nikolaev; F. F. Pavlov
2005-12-05T23:59:59.000Z
The spin filtering in storage rings is based on the multiple passage of a stored beam through a polarized internal gas target. Apart from the polarization by transmission, a unique geometrical feature of interaction with the target in such a filtering process, pointed out by H.O. Meyer \\cite{Meyer}, is a scattering of stored particles within the beam. A rotation of the spin in the scattering process affects the polarization buildup. We derive here a quantum-mechanical evolution equation for the spin-density matrix of the stored beam which incorporates scattering within the beam. We show how the interplay of transmission and scattering with the beam changes from polarized electrons to polarized protons in the atomic target. After discussions of the FILTEX results on the filtering of stored protons \\cite{FILTEX}, we comment on the strategy of spin filtering of antiprotons for the PAX experiment at GSI FAIR \\cite{PAX-TP}.
RHIC Spin Flipper Commissioning Status
Bai, M.; Meot, F.; Dawson, C.; Oddo, P.; Pai, C.; Pile, P.; Makdisi, Y.; Meng, W.; Roser, T.
2010-05-23T23:59:59.000Z
The commissioning of the RHIC spin flipper in the RHIC Blue ring during the RHIC polarized proton run in 2009 showed the detrimental effects of global vertical coherent betatron oscillation induced by the 2-AC dipole plus 4-DC dipole configuration. This global orbital coherent oscillation of the RHIC beam in the Blue ring in the presence of collision modulated the beam-beam interaction between the two RHIC beams and affected Yellow beam polarization. The experimental data at injection with different spin tunes by changing the snake current also demonstrated that it was not possible to induce a single isolated spin resonance with the global vertical coherent betatron oscillation excited by the two AC dipoles. Hence, a new design was proposed to eliminate the coherent vertical betatron oscillation outside the spin flipper by adding three additional AC dipoles. This paper presents the experimental results as well as the new design.
Grames, J M; Benesch, J F; Clark, J; Hansknecht, J; Kazimi, R; Machie, D; Poelker, M; Stutzman, M L; Suleiman, R
2011-03-01T23:59:59.000Z
A new 4pi spin manipulator composed of two Wien filters oriented orthogonally and separated by two solenoids has been installed at the CEBAF/Jefferson Lab photoinjector. The new spin manipulator is used to precisely set the electron spin direction at an experiment in any direction (in or out of plane of the accelerator) and provides the means to reverse, or flip, the helicity of the electron beam on a daily basis. This reversal is being employed to suppress systematic false asymmetries that can jeopardize challenging parity violation experiments that strive to measure increasingly small physics asymmetries [*,**,***]. The spin manipulator is part of the ultra-high vacuum polarized electron source beam line and has been successfully operated with 100keV and 130keV electron beam at high current (>100 microAmps). A unique feature of the device is that spin-flipping requires only the polarity of one solenoid magnet be changed. Performance characteristics of the Two Wien Filter Spin Flipper will be summarized.
Solid-State NMR Study of Intercalated Species in Poly( -caprolactone)/Clay Nanocomposites
Paris-Sud XI, Université de
Solid-State NMR Study of Intercalated Species in Poly( - caprolactone)/Clay Nanocomposites J of surfactant and polymer chains in intercalated poly( - caprolactone)/clay nanocomposites are characterized by 31 P magic-angle spinning (MAS) and 13 C cross-polarization MAS NMR techniques. To obtain hybrid
angle elastic scattering: Topics by E-print Network
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hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is...
angle hysteresis effects: Topics by E-print Network
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of 1 eV or less, increasing Wadley, Haydn 155 Dynamics and hysteresis in square lattice artificial spin-ice G. M. Wysin Physics Websites Summary: interactions can be satisfied...
SU-E-I-56: Scan Angle Reduction for a Limited-Angle Intrafraction Verification (LIVE) System
Ren, L; Zhang, Y; Yin, F [Duke University Medical Center, Durham, NC (United States)
2014-06-01T23:59:59.000Z
Purpose: To develop a novel adaptive reconstruction strategy to further reduce the scanning angle required by the limited-angle intrafraction verification (LIVE) system for intrafraction verification. Methods: LIVE acquires limited angle MV projections from the exit fluence of the arc treatment beam or during gantry rotation between static beams. Orthogonal limited-angle kV projections are also acquired simultaneously to provide additional information. LIVE considers the on-board 4D-CBCT images as a deformation of the prior 4D-CT images, and solves the deformation field based on deformation models and data fidelity constraint. LIVE reaches a checkpoint after a limited-angle scan, and reconstructs 4D-CBCT for intrafraction verification at the checkpoint. In adaptive reconstruction strategy, a larger scanning angle of 30° is used for the first checkpoint, and smaller scanning angles of 15° are used for subsequent checkpoints. The onboard images reconstructed at the previous adjacent checkpoint are used as the prior images for reconstruction at the current checkpoint. As the algorithm only needs to reconstruct the small deformation occurred between adjacent checkpoints, projections from a smaller scan angle provide enough information for the reconstruction. XCAT was used to simulate tumor motion baseline drift of 2mm along sup-inf direction at every subsequent checkpoint, which are 15° apart. Adaptive reconstruction strategy was used to reconstruct the images at each checkpoint using orthogonal 15° kV and MV projections. Results: Results showed that LIVE reconstructed the tumor volumes accurately using orthogonal 15° kV-MV projections. Volume percentage differences (VPDs) were within 5% and center of mass shifts (COMS) were within 1mm for reconstruction at all checkpoints. Conclusion: It's feasible to use an adaptive reconstruction strategy to further reduce the scan angle needed by LIVE to allow faster and more frequent intrafraction verification to minimize the treatment errors in lung cancer treatments. Grant from Varian Medical System.
angle diffraction studies: Topics by E-print Network
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A. 3 DMSO-Induced Dehydration of DPPC Membranes Studied by X-ray Diffraction, Small-Angle Neutron Scattering, and Calorimetry Condensed Matter (arXiv) Summary: The influence of...
Bond Angle Torsion http://www.nobelprize.org/
Fukai, Tomoki
MARBLE-K 20141024 1 #12;2 MARBLE MARBLE #12;MD Bond Angle Torsion http) MARBLE-K PME CHARMM Force Field AMBER Force Field NMRSAXS molx XNMR #12;MARBLE
Modelling contact angle hysteresis on chemically patterned and superhydrophobic surfaces
H. Kusumaatmaja; J. M. Yeomans
2006-11-03T23:59:59.000Z
We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasi-statically increased and decreased. We consider both two, and three, dimensions using analytical and numerical approaches to minimise the free energy of the drop. In two dimensions we find, in agreement with other authors, a slip, jump, stick motion of the contact line. In three dimensions this behaviour persists, but the position and magnitude of the contact line jumps are sensitive to the details of the surface patterning. In two dimensions we identify analytically the advancing and receding contact angles on the different surfaces and we use numerical insights to argue that these provide bounds for the three dimensional cases. We present explicit simulations to show that a simple average over the disorder is not sufficient to predict the details of the contact angle hysteresis, and to support an explanation for the low contact angle hysteresis of suspended drops on superhydrophobic surfaces.
Contact angles in the pseudopotential lattice Boltzmann modeling of wetting
Q. Li; K. H. Luo; Q. J. Kang; Q. Chen
2014-10-21T23:59:59.000Z
In this paper, we aim to investigate the implementation of contact angles in the pseudopotential lattice Boltzmann modeling of wetting at a large density ratio. The pseudopotential lattice Boltzmann model [X. Shan and H. Chen, Phys. Rev. E 49, 2941 (1994)] is a popular mesoscopic model for simulating multiphase flows and interfacial dynamics. In this model, the contact angle is usually realized by a fluid-solid interaction. Two widely used fluid-solid interactions: the density-based interaction and the pseudopotential-based interaction, as well as a modified pseudopotential-based interaction formulated in the present paper, are numerically investigated and compared in terms of the achievable contact angles, the maximum and the minimum densities, and the spurious currents. It is found that the pseudopotential-based interaction works well for simulating small static (liquid) contact angles, however, is unable to reproduce static contact angles close to 180 degrees. Meanwhile, it is found that the proposed modified pseudopotential-based interaction performs better in light of the maximum and the minimum densities and is overall more suitable for simulating large contact angles as compared with the other two types of fluid-solid interactions. Furthermore, the spurious currents are found to be enlarged when the fluid-solid interaction force is introduced. Increasing the kinematic viscosity ratio between the vapor and liquid phases is shown to be capable of reducing the spurious currents caused by the fluid-solid interactions.
Accepted Manuscript Using Small Angle Solution Scattering Data in Xplor-NIH Structure Calcula-
Clore, G. Marius
and wide angle X-ray and small angle neutron scattering for biomolecular structure calculation using and wide angle X-ray scattering (SAXS/WAXS) and small angle neutron scattering (SANS) data, on the otherAccepted Manuscript Using Small Angle Solution Scattering Data in Xplor-NIH Structure Calcula
Localizable entanglement in antiferromagnetic spin chains
Jin, B.-Q.; Korepin, V.E. [C.N. Yang Institute for Theoretical Physics, State University of New York at Stony Brook, Stony Brook, New York 11794-3840 (United States)
2004-06-01T23:59:59.000Z
Antiferromagnetic spin chains play an important role in condensed matter and statistical mechanics. Recently XXX spin chain was discussed in relation to information theory. Here we consider localizable entanglement. It is how much entanglement can be localized on two spins by performing local measurements on other individual spins (in a system of many interacting spins). We consider the ground state of antiferromagnetic spin chain. We study localizable entanglement [represented by concurrence] between two spins. It is a function of the distance. We start with isotropic spin chain. Then we study effects of anisotropy and magnetic field. We conclude that anisotropy increases the localizable entanglement. We discovered high sensitivity to a magnetic field in cases of high symmetry. We also evaluated concurrence of these two spins before the measurement to illustrate that the measurement raises the concurrence.
Spin transport in lateral spin valves and across a metal- insulator transition in V?O? /
Erekhinsky, Mikhail
2013-01-01T23:59:59.000Z
J. Ansermet, Spin-dependent Peltier effect of perpendicularB. van Wees, Interplay of Peltier and Seebeck Effects inspin Seebeck coefficient. Peltier or spin blockade effects
Aleksi?, J; Antoranz, P; Backes, M; Barrio, J A; Bastieri, D; González, J Becerra; Bednarek, W; Berdyugin, A; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Boller, A; Bonnoli, G; Bordas, P; Tridon, D Borla; Bosch-Ramon, V; Bose, D; Braun, I; Bretz, T; Camara, M; Cañellas, A; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cossio, L; Cortina, J; Covino, S; Dazzi, F; De Angelis, A; del Pozo, E De Cea; De Lotto, B; De Maria, M; De Sabata, F; Mendez, C Delgado; Ortega, A Diago; Doert, M; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Elsaesser, D; Errando, M; Ferenc, D; Fonseca, M V; Font, L; López, R J García; Garczarczyk, M; Giavitto, G; Godinovi?, N; Hadasch, D; Herrero, A; Hildebrand, D; Höhne-Mönch, D; Hose, J; Hrupec, D; Jogler, T; Klepser, S; Krähenbühl, T; Kranich, D; Krause, J; La Barbera, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Makariev, M; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Miranda, J M; Mirzoyan, R; Miyamoto, H; Moldón, J; Moralejo, A; Nieto, D; Nilsson, K; Orito, R; Oya, I; Paoletti, R; Paredes, J M; Partini, S; Pasanen, M; Pauss, F; Pegna, R G; Perez-Torres, M A; Persic, M; Peruzzo, L; Pochon, J; Prada, F; Moroni, P G Prada; Prandini, E; Puchades, N; Puljak, I; Reichardt, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rügamer, S; Saggion, A; Saito, K; Saito, T Y; Salvati, M; Sánchez-Conde, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shayduk, M; Shore, S N; Sierpowska-Bartosik, A; Sillanpää, A; Sitarek, J; Sobczynska, D; Spanier, F; Spiro, S; Stamerra, A; Steinke, B; Storz, J; Strah, N; Struebig, J C; Suric, T; Takalo, L; Tavecchio, F; Temnikov, P; Terzi?, T; Tescaro, D; Teshima, M; Torres, D F; Vankov, H; Wagner, R M; Weitzel, Q; Zabalza, V; Zandanel, F; Zanin, R; Neronov, A; Pfrommer, C; Pinzke, A; Semikoz, D V
2015-01-01T23:59:59.000Z
We report on the detection with the MAGIC telescopes of very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster, observed during the interval November 2008 to February 2010. The Fermi satellite has also detected this galaxy. The source is detected by MAGIC at a high statistical significance of 7.6sigma in 20.6 hr of stereo data. The observed spectral energy distribution is flat with a differential spectral index of -2.00 \\pm 0.14. The mean flux above 300 GeV, between October 2009 and February 2010, (3.1 \\pm 0.5)x10^{-12} cm^{-2} s^{-1}, corresponds to (2.5 \\pm 0.4)% of Crab Nebula units. Only an upper limit, of 1.9% of Crab Nebula units above 300 GeV, was obtained with the 2008 data. This, together with strong hints (>3sigma) of flares in the middle of October and November 2009, implies that the emission is variable. The MAGIC results favour a scenario with the very high energy emission originating from the inner jet close to the central engine. More complicated models ...
Spin dynamics in the strong spin-orbit coupling regime
Liu, Xin; Liu, Xiong-Jun; Sinova, Jairo.
2011-01-01T23:59:59.000Z
direction is constructed by the superposition of the two electrons with wave vectors k and k + q. In this case, the spin precession frequency will be#15;1(2) #15; #15;0(1? qQ ), where Q = 2m?1. damped oscillatory modes in the clean system corresponding... mode is zero for all of the electron momentum k. On the 035318-4 SPIN DYNAMICS IN THE STRONG SPIN-ORBIT . . . PHYSICAL REVIEW B 84, 035318 (2011) 0 0.5 1 1.5 2 0.2 0.4 0.6 0.8 1 q/Q (i R e Im ? ? ) ?so? = 0.4 ?so? = 0.5 ?so? = 0.6 ?so...
Spin transport in benzofurane bithiophene based organic spin valves
Palosse, Mathieu; Séguy, Isabelle; Bedel-Pereira, Élena [CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse (France) [CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse (France); Université de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France)] [France; Villeneuve-Faure, Christina [Université de Toulouse (France) [Université de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; LAPLACE, Université Paul Sabatier, 118, route de Narbonne 31062 Toulouse Cedex 9 (France); Mallet, Charlotte; Frère, Pierre [MOLTECH-Anjou, UMR CNRS 6200, Université d’Angers, 2 Bd Lavoisier 49045 ANGERS Cedex (France)] [MOLTECH-Anjou, UMR CNRS 6200, Université d’Angers, 2 Bd Lavoisier 49045 ANGERS Cedex (France); Warot-Fonrose, Bénédicte; Biziere, Nicolas [Université de Toulouse (France) [Université de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; CNRS, CEMES-CNRS UPR 8011, 29 rue Jeanne Marvig, BP 94347, FR-31055 Toulouse Cedex 4 (France); Bobo, Jean-François, E-mail: jfbobo@cemes.fr [Université de Toulouse (France) [Université de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; CNRS, CEMES-ONERA, NMH, 2 avenue Edouard Belin, FR-31055 Toulouse Cedex 4 (France)
2014-01-15T23:59:59.000Z
In this paper we present spin transport in organic spin-valves using benzofurane bithiophene (BF3) as spacer layer between NiFe and Co ferromagnetic electrodes. The use of an AlO{sub x} buffer layer between the top electrode and the organic layer is discussed in terms of improvements of stacking topology, electrical transport and oxygen contamination of the BF3 layer. A study of magnetic hysteresis cycles evidences spin-valve behaviour. Transport properties are indicative of unshorted devices with non-linear I-V characteristics. Finally we report a magnetoresistance of 3% at 40 K and 10 mV in a sample with a 50 nm thick spacer layer, using an AlO{sub x} buffer layer.
Controllable spin entanglement production in a quantum spin Hall ring
Anders Ström; Henrik Johannesson; Patrik Recher
2015-03-13T23:59:59.000Z
We study the entanglement production in a quantum spin Hall ring geometry where electrons of opposite spins are emitted in pairs from a source and collected in two different detectors. Postselection of coincidence detector events gives rise to entanglement in the system, measurable through correlations between the outcomes in the detectors. We have chosen a geometry such that the entanglement depends on the dynamical phases picked up by the edge states as they move around the ring. In turn, the dependence of the phases on gate potential and Rashba interaction allows for a precise electrical control of the entanglement production in the ring.
Analytic bootstrap at large spin
Apratim Kaviraj; Kallol Sen; Aninda Sinha
2015-03-24T23:59:59.000Z
We use analytic conformal bootstrap methods to determine the anomalous dimensions and OPE coefficients for large spin operators in general conformal field theories in four dimensions containing a scalar operator of conformal dimension $\\Delta_\\phi$. It is known that such theories will contain an infinite sequence of large spin operators with twists approaching $2\\Delta_\\phi+2n$ for each integer $n$. By considering the case where such operators are separated by a twist gap from other operators at large spin, we analytically determine the $n$, $\\Delta_\\phi$ dependence of the anomalous dimensions. We find that for all $n$, the anomalous dimensions are negative for $\\Delta_\\phi$ satisfying the unitarity bound, thus extending the Nachtmann theorem to non-zero $n$. In the limit when $n$ is large, we find agreement with the AdS/CFT prediction corresponding to the Eikonal limit of a 2-2 scattering with dominant graviton exchange.
Analytic bootstrap at large spin
Kaviraj, Apratim; Sinha, Aninda
2015-01-01T23:59:59.000Z
We use analytic conformal bootstrap methods to determine the anomalous dimensions and OPE coefficients for large spin operators in general conformal field theories in four dimensions containing a scalar operator of conformal dimension $\\Delta_\\phi$. It is known that such theories will contain an infinite sequence of large spin operators with twists approaching $2\\Delta_\\phi+2n$ for each integer $n$. By considering the case where such operators are separated by a twist gap from other operators at large spin, we analytically determine the $n$, $\\Delta_\\phi$ dependence of the anomalous dimensions. We find that for all $n$, the anomalous dimensions are negative for $\\Delta_\\phi$ satisfying the unitarity bound, thus extending the Nachtmann theorem to non-zero $n$. In the limit when $n$ is large, we find agreement with the AdS/CFT prediction corresponding to the Eikonal limit of a 2-2 scattering with dominant graviton exchange.
Transverse spin effects in COMPASS
A. Bressan; for the COMPASS experiment
2009-02-02T23:59:59.000Z
In the years 2002-2004 COMPASS has collected data with the LiD target polarization oriented transversely with respect to the muon beam direction for about 20% of the running time, to measure transverse spin effects in semi-inclusive deep inelastic scattering, one of the main objectives of the COMPASS spin program. In 2007, COMPASS has used for the first time a proton NH_3 target with the data taking time equally shared between longitudinal and transverse polarization of the target. After reviewing the results obtained with the deuteron, the new results for the Collins and Sivers asymmetries of the proton will be presented.
Rajeev Singh; Subinay Dasgupta; Sitabhra Sinha
2010-11-23T23:59:59.000Z
Homogeneous populations of oscillators have recently been shown to exhibit stable coexistence of coherent and incoherent regions. Generalizing the concept of chimera states to the context of order-disorder transition in systems at thermal equilibrium, we show analytically that such complex ordering can appear in a system of Ising spins, possibly the simplest physical system exhibiting this phenomenon. We also show numerically the existence of chimera ordering in 3-dimensional spin systems that model layered magnetic materials, suggesting possible means of experimentally observing such states.
Vladimir Baryshevsky
2002-02-14T23:59:59.000Z
Spin rotation and oscillation phenomena of particles captured in a gas target through which beam of high energy particles passes is discussed. Such experiment arrangement make it realizable for storage ring and allows to study zero-angle scattering amplitude at highest possible energies.
An antidot array as an edge for total non-reflection of spin waves in yttrium iron garnet films
Gieniusz, R., E-mail: gieniusz@uwb.edu.pl; Guzowska, U.; Maziewski, A. [Faculty of Physics, University of Bia?ystok, Lipowa 41, 15-424 Bia?ystok (Poland); Bessonov, V. D. [Faculty of Physics, University of Bia?ystok, Lipowa 41, 15-424 Bia?ystok (Poland); Institute of Metal Physics, Ural Division of RAS, Yekaterinburg 620041 (Russian Federation); Stognii, A. I. [Scientific-Practical Materials Research Center at National Academy of Sciences of Belarus, ul. P. Brovki 19, Minsk 220072 (Belarus)
2014-02-24T23:59:59.000Z
An array of antidots has been used as an edge to create the phenomenon of total non-reflection of spin waves in yttrium iron garnet films. At the critical angle between the line of antidots and the magnetic field, we observe a high-intensity beam of spin waves moving along the line of antidots. The properties of these waves are investigated experimentally by Brillouin light scattering spectroscopy. The conditions required for the occurrence of this phenomenon based on an analysis of the properties of the isofrequency dependencies are presented. The numerical simulations are in good agreement with those of the experimental measurements.
Control of single spin in Markovian environment
Yuan, Haidong
In this article we study the control of single spin in Markovian environment. Given an initial state, we compute all the possible states to which the spin can be driven at arbitrary time, under the assumption that fast ...
Discussion on spin-flip synchrotron radiation
V. A. Bordovitsyn; V. S. Gushchina; A. N. Myagkii
2001-02-12T23:59:59.000Z
Quantum spin-flip transitions are of great importance in the synchrotron radiation theory. For better understanding of the nature of this phenomenon, it is necessary to except the effects connected with the electric charge radiation from observation. This fact explains the suggested choice of the spin-flip radiation model in the form of radiation of the electric neutral Dirac-Pauli particle moving in the homogeneous magnetic field. It is known that in this case, the total radiation in the quantum theory is conditioned by spin-flip transitions. The idea is that spin-flip radiation is represented as a nonstationary process connected with spin precession. We shall shown how to construct a solution of the classical equation of the spin precession in the BMT theory having the exact solution of the Dirac-Pauli equation.Thus, one will find the connection of the quantum spin-flip transitions with classical spin precession.
Functional Keldysh theory of spin torques
Duine, R. A.; Nunez, A. S.; Sinova, Jairo; MacDonald, A. H.
2007-01-01T23:59:59.000Z
stochastic Landau-Lifschitz-Gilbert equation with spin-transfer torques. We calculate the Gilbert damping parameter alpha and the nonadiabatic spin transfer torque parameter beta for a model ferromagnet. We find that beta not equal alpha, in agreement...
Spin-orbit interactions of light
Bliokh, K Y; Nori, F; Zayats, A V
2015-01-01T23:59:59.000Z
Light carries spin and orbital angular momentum. These dynamical properties are determined by the polarization and spatial degrees of freedom of light. Modern nano-optics, photonics, and plasmonics, tend to explore subwavelength scales and additional degrees of freedom of structured, i.e., spatially-inhomogeneous, optical fields. In such fields, spin and orbital properties become strongly coupled with each other. We overview the fundamental origins and important applications of the main spin-orbit interaction phenomena in optics. These include: spin-Hall effects in inhomogeneous media and at optical interfaces, spin-dependent effects in nonparaxial (focused or scattered) fields, spin-controlled shaping of light using anisotropic structured interfaces (metasurfaces), as well as robust spin-directional coupling via evanescent near fields. We show that spin-orbit interactions are inherent in all basic optical processes, and they play a crucial role at subwavelength scales and structures in modern optics.
Noeel, N. E. D.; Read, J. I. [ETH Zuerich, Institute for Astronomy, Wolfgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); Conn, B. C.; Rix, H.-W. [Max Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Carrera, R. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain); Dolphin, A., E-mail: noelia@phys.ethz.ch [Raytheon Company, P.O. Box 11337, Tucson, AZ 85734-1337 (United States)
2013-05-10T23:59:59.000Z
The origin of the gas in between the Magellanic Clouds (MCs)-known as the ''Magellanic Bridge'' (MB)-is puzzling. Numerical simulations suggest that the MB formed from tidally stripped gas and stars in a recent interaction between the MCs. However, the apparent lack of stripped intermediate- or old-age stars associated with the MB is at odds with this picture. In this paper, we present the first results from the MAGellanic Inter-Cloud program (MAGIC) aimed at probing the stellar populations in the inter-Cloud region. We present observations of the stellar populations in two large fields located in between the Large and Small Magellanic Clouds (LMC/SMC), secured using the WFI camera on the 2.2 m telescope in La Silla. Using a synthetic color-magnitude diagram technique, we present the first quantitative evidence for the presence of intermediate-age and old stars in the inter-Cloud region. The intermediate-age stars-which make up {approx}28% of all stars in the region-are not present in fields at a similar distance from the SMC in a direction pointing away from the LMC. This provides potential evidence that these intermediate-age stars could have been tidally stripped from the SMC. However, spectroscopic studies will be needed to confirm or rule out the tidal origin for the inter-Cloud gas and stars.
Physical region for three-neutrino mixing angles
D. C. Latimer; D. J. Ernst
2004-10-11T23:59:59.000Z
We derive a set of symmetry relations for the three-neutrino mixing angles, including the MSW matter effect. Though interesting in their own right, these relations are used to choose the physical region of the mixing angles such that oscillations are parameterized completely and uniquely. We propose that the preferred way of setting the bounds on the mixing angles should be $\\theta_{12} \\in [0,\\pi/2]$, $\\theta_{13} \\in [-\\pi/2,\\pi/2]$, $\\theta_{23}\\in [0,\\pi/2]$, and $\\delta \\in [0,\\pi)$. No CP violation then results simply from setting $\\delta=0$. In the presence of the MSW effect, this choice of bounds is a new result. Since the size of the asymmetry about $\\theta_{13} = 0$ is dependent on the details of the data analysis and is a part of the results of the analysis, we argue that the negative values of $\\theta_{13}$ should not be ignored.
Opening angles and shapes of parsec-scale AGN jets
Pushkarev, Alexander B; Kovalev, Yuri Y; Savolainen, Tuomas
2015-01-01T23:59:59.000Z
We used 15 GHz VLBA observations of 366 sources having at least 5 epochs within a time interval 1995-2013 from the MOJAVE program and/or its predecessor, the 2 cm VLBA Survey. For each source we produced a corresponding stacked image averaging all available epochs for a better reconstruction of the cross section of the flow. We have analyzed jet profiles transverse to the local jet ridge line and derived both apparent and intrinsic opening angles of the parsec-scale outflows. The sources detected by the Fermi Large Area Telescope (LAT) during the first 24 months of operation show wider apparent jet opening angle and smaller viewing angles on a very high level of significance supporting our early findings. Analyzing transverse shapes of the outflows we found that most sources have conical jet geometry at parsec scales, though there are also sources that exhibit active jet collimation.
Shu Luo
2011-12-14T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana neutrinos the RG-evolutions of Phi, Psi and the Jarlskog strongly depend on the Majorana-type CP-violating parameters and are quite sensitive to the sign of Delta m^{2}_{31}. They may receive significant radiative corrections in the MSSM if three neutrino masses are nearly degenerate.
Luo, Shu
2011-01-01T23:59:59.000Z
Enlightened by the idea of the 3 times 3 CKM angle matrix proposed recently by Harrison et al., we introduce the Dirac angle matrix Phi and the Majorana angle matrix Psi in the lepton sector for Dirac and Majorana neutrinos respectively. We show that in presence of the CP violation, the angle matrix Phi or Psi is entirely equivalent to the complex MNS matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles (UTs) and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop Renormalization Group Equations (RGEs) of Phi, Psi and some other rephasing invariant parameters are derived and the numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana ne...
Off-Angle Iris Correction using a Biological Model
Thompson, Joseph T [ORNL] [ORNL; Santos-Villalobos, Hector J [ORNL] [ORNL; Karakaya, Mahmut [ORNL] [ORNL; Barstow, Del R [ORNL] [ORNL; Bolme, David S [ORNL] [ORNL; Boehnen, Chris Bensing [ORNL] [ORNL
2013-01-01T23:59:59.000Z
This work implements an eye model to simulate corneal refraction effects. Using this model, ray tracing is performed to calculate transforms to remove refractive effects in off-angle iris images when reprojected to a frontal view. The correction process is used as a preprocessing step for off-angle iris images for input to a commercial matcher. With this method, a match score distribution mean improvement of 11.65% for 30 degree images, 44.94% for 40 degree images, and 146.1% improvement for 50 degree images is observed versus match score distributions with unmodi ed images.
Angle of Arrival Detection with Fifth Order Phase Operators
Khmou, Youssef
2015-01-01T23:59:59.000Z
In this paper, a fifth order propagator operators are proposed for estimating the Angles Of Arrival (AOA) of narrowband electromagnetic waves impinging on antenna array when its number of sensors is larger than the number of radiating sources. The array response matrix is partitioned into five linearly dependent phases to construct the noise projector using five different propagators from non diagonal blocks of the spectral matrice of the received data; hence, five different estimators are proposed to estimate the angles of the sources. The simulation results proved the performance of the proposed estimators in the presence of white noise comparatively to high resolution eigen based spectra.
Cerchiai, Bianca L; Bertini, S.; Cacciatori, Sergio L.
2005-10-20T23:59:59.000Z
In this paper we reconsider the problem of the Euler parametrization for the unitary groups. After constructing the generic group element in terms of generalized angles, we compute the invariant measure on SU(N) and then we determine the full range of the parameters, using both topological and geometrical methods. In particular, we show that the given parametrization realizes the group SU(N+1) as a fibration of U(N) over the complex projective space CP{sup n}. This justifies the interpretation of the parameters as generalized Euler angles.
Inverse spin Hall effect induced by spin pumping into semiconducting ZnO
Lee, Jung-Chuan [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Huang, Leng-Wei [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China); Hung, Dung-Shing, E-mail: dshung@mail.mcu.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Department of Information and Telecommunications Engineering, Ming Chuan University, Taipei 111, Taiwan (China); Chiang, Tung-Han [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Huang, J. C. A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Liang, Jun-Zhi [Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Physics, Fu Jen Catholic University, Taipei 242, Taiwan (China); Lee, Shang-Fan, E-mail: leesf@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China)
2014-02-03T23:59:59.000Z
The inverse spin Hall effect (ISHE) of n-type semiconductor ZnO thin films with weak spin-orbit coupling has been observed by utilizing the spin pumping method. In the ferromagnetic resonance condition, the spin pumping driven by the dynamical exchange interaction of a permalloy film injects a pure spin current into the adjacent ZnO layer. This spin current gives rise to a DC voltage through the ISHE in the ZnO layer, and the DC voltage is proportional to the microwave excitation power. The effect is sizeable even when the spin backflow is considered.
The XY Spin Chain Random Block Operators
Jung, Paul
The XY Spin Chain Random Block Operators Proof of Main Result Open Questions Localization for Random Block Operators Related to the XY Spin Chain Jacob W. Chapman Division of Science Southern Wesleyan University Central, SC Joint work with GÂ¨unter Stolz UAB NSF-CBMS Conference on Quantum Spin
Quantum superintegrable system for arbitrary spin
G. Pronko
2007-09-20T23:59:59.000Z
In [1] was considered the superintegrable system which describes the magnetic dipole with spin 1/2 (neutron) in the field of linear current. Here we present its generalization for any spin which preserves superintegrability. The dynamical symmetry stays the same as it is for spin 1/2.
Spinning particles in scalar-tensor gravity
D. A. Burton; R. W. Tucker; C. H. Wang
2007-11-20T23:59:59.000Z
We develop a new model of a spinning particle in Brans-Dicke spacetime using a metric-compatible connection with torsion. The particle's spin vector is shown to be Fermi-parallel (by the Levi-Civita connection) along its worldline (an autoparallel of the metric-compatible connection) when neglecting spin-curvature coupling.
SPINNING THE SEMANTIC WEB INTRODUCTION
Wahlster, Wolfgang - Deutsche Forschungszentrum fÃ¼r KÃ¼nstliche Intelligenz & FR 6.2
SPINNING THE SEMANTIC WEB INTRODUCTION Dieter Fensel, Jim Hendler, Henry Lieberman, and Wolfgang Wahlster The World Wide Web (WWW) has drastically changed the availability of electronically accessible (http://www.w3c.org) expects around a billion Web users and an even higher number of available documents
Switzner, Nathan; Henry, Dick
2009-03-20T23:59:59.000Z
In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.
High-spin nuclear spectroscopy
Diamond, R.M.
1986-07-01T23:59:59.000Z
High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)
Tripathi, Anjali
2009-01-01T23:59:59.000Z
In this thesis, I present new spectroscopic and photometric observations of WASP-3, a transiting extrasolar planetary system. From spectra obtained during two transits, I use the Rossiter-McLaughlin effect in a simplified ...
Spinning Reserve From Responsive Loads
Kirby, B.J.
2003-04-08T23:59:59.000Z
Responsive load is the most underutilized reliability resource available to the power system today. It is currently not used at all to provide spinning reserve. Historically there were good reasons for this, but recent technological advances in communications and controls have provided new capabilities and eliminated many of the old obstacles. North American Electric Reliability Council (NERC), Federal Energy Regulatory Commission (FERC), Northeast Power Coordinating Council (NPCC), New York State Reliability Council (NYSRC), and New York Independent System Operator (NYISO) rules are beginning to recognize these changes and are starting to encourage responsive load provision of reliability services. The Carrier ComfortChoice responsive thermostats provide an example of these technological advances. This is a technology aimed at reducing summer peak demand through central control of residential and small commercial air-conditioning loads. It is being utilized by Long Island Power Authority (LIPA), Consolidated Edison (ConEd), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E). The technology is capable of delivering even greater response in the faster spinning reserve time frame (while still providing peak reduction). Analysis of demand reduction testing results from LIPA during the summer of 2002 provides evidence to back up this claim. It also demonstrates that loads are different from generators and that the conventional wisdom, which advocates for starting with large loads as better ancillary service providers, is flawed. The tempting approach of incrementally adapting ancillary service requirements, which were established when generators were the only available resources, will not work. While it is easier for most generators to provide replacement power and non-spinning reserve (the slower response services) than it is to supply spinning reserve (the fastest service), the opposite is true for many loads. Also, there is more financial reward for supplying spinning reserve than for supplying the other reserve services as a result of the higher spinning reserve prices. The LIPAedge program (LIPA's demand reduction program using Carrier ComfortChoice thermostats) provides an opportunity to test the use of responsive load for spinning reserve. With potentially 75 MW of spinning reserve capability already installed, this test program can also make an important contribution to the capacity needs of Long Island during the summer of 2003. Testing could also be done at ConEd ({approx}30 MW), SCE ({approx}15 MW), and/or SDG&E ({approx}15 MW). This paper is divided into six chapters. Chapter 2 discusses the contingency reserve ancillary services, their functions in supporting power system reliability, and their technical requirements. It also discusses the policy and tariff requirements and attempts to distinguish between ones that are genuinely necessary and ones that are artifacts of the technologies that were historically used to provide the services. Chapter 3 discusses how responsive load could provide contingency reserves (especially spinning reserve) for the power system. Chapter 4 specifically discusses the Carrier ComfortChoice responsive thermostat technology, the LIPAedge experience with that technology, and how the technology could be used to supply spinning reserve. Chapter 5 discusses a number of unresolved issues and suggests areas for further research. Chapter 6 offers conclusions and recommendations.
Werner Bernreuther; Zong-Guo Si
2015-03-16T23:59:59.000Z
A number of top-spin observables are computed within the Standard Model (SM), at next-to-leading order in the strong and weak gauge couplings for hadronic top-quark anti-quark (ttbar) production and decay at the LHC for center-of-mass energies 7 and 8 TeV. For dileptonic final states we consider the azimuthal angle correlation, the helicity correlation, and the opening angle distribution; for lepton plus jets final states we determine distributions and asymmetries that trace a longitudinal and transverse polarization, respectively, of the t and t-bar samples. In addition, we investigate the effects of a non-zero chromo-magnetic and chromo-electric dipole moment of the top quark on these and other top-spin observables and associated asymmetries. These observables allow to disentangle the contributions from the real and imaginary parts of these moments.
Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation
Wind Turbine Pitch Angle Controllers for Grid Frequency Stabilisation Clemens Jauch Risø National Laboratory Wind Energy Department P.O. Box 49 DK-4000 Roskilde, Denmark clemens.jauch@risoe.dk Abstract: In this paper it is investigated how active-stall wind turbines can contribute to the stabilisation of the power
angle neutron scattering: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
neutron scattering First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 SANS -Small Angle Neutron Scattering...
Overview of Neutrino Mixing Models and Their Mixing Angle Predictions
Albright, Carl H.
2009-11-01T23:59:59.000Z
An overview of neutrino-mixing models is presented with emphasis on the types of horizontal flavor and vertical family symmetries that have been invoked. Distributions for the mixing angles of many models are displayed. Ways to differentiate among the models and to narrow the list of viable models are discussed.
Experimental Evaluation of an Angle Based Indoor Localization System
Nasipuri, Asis
Experimental Evaluation of an Angle Based Indoor Localization System Asis Nasipuri and Ribal El available off-the-shelf components. Wireless sensor nodes equipped with photo sensors determine is required at the sensor nodes. The system also does not involve any centralized server or off
Measurements of the angle alpha (phi2) at B factories
G. Vasseur
2008-10-02T23:59:59.000Z
The measurements of the angle alpha (phi2) of the unitarity triangle at the B factories are reviewed. The value of alpha determined by combining the results obtained in the B to pi pi, B to rho pi, and B to rho rho modes by both the BABAR and Belle experiments is (87.5 +6.2 -5.3) degrees.
SANS -Small Angle Neutron Scattering Tcnica de difrao
Loh, Watson
SANS - Small Angle Neutron Scattering Técnica de difração informações sobre tamanho e forma de- Neutrons are created in the centre of the target station when the beam of high energy protons collides by evaporating nuclear particles, mainly neutrons, in all directions. Each proton produces approximately 15
Neutrino Mass Models: Impact of non-zero reactor angle
Stephen F. King
2011-06-25T23:59:59.000Z
In this talk neutrino mass models are reviewed and the impact of a non-zero reactor angle and other deviations from tri-bimaximal mixing are discussed. We propose some benchmark models, where the only way to discriminate between them is by high precision neutrino oscillation experiments.
Rapid and robust spin state amplification
Tom Close; Femi Fadugba; Simon C. Benjamin; Joseph Fitzsimons; Brendon W. Lovett
2011-05-24T23:59:59.000Z
Electron and nuclear spins have been employed in many of the early demonstrations of quantum technology (QT). However applications in real world QT are limited by the difficulty of measuring single spins. Here we show that it is possible to rapidly and robustly amplify a spin state using a lattice of ancillary spins. The model we employ corresponds to an extremely simple experimental system: a homogenous Ising-coupled spin lattice in one, two or three dimensions, driven by a continuous microwave field. We establish that the process can operate at finite temperature (imperfect initial polarisation) and under the effects of various forms of decoherence.
Repeated measurements and nuclear spin polarization
Lian-Ao Wu
2010-08-11T23:59:59.000Z
We study repeated (noncontinuous) measurements on the electron spin in a quantum dot and find that the measurement technique may lead to a different met$ or mechanism to realize nuclear spin polarization. While it may be used in any case, the method is aimed at the further polarization, providing that nuclear spins have been polarized by the existent electrical or optical methods. The feasibility of the method is analyzed. The existing techniques in electron spin measurements are applicable to this scheme. The repeated measurements \\emph{deform} the structures of the nuclear wave function and can also serve as $\\emph{gates}$ to manipulate nuclear spins.
Spin orientation of supermassive black holes in active galaxies
W. Kollatschny
2003-11-12T23:59:59.000Z
Accretion of gas onto a central supermassive black hole is generally accepted to be the source of the emitted energy in active galactic nuclei.The broad emission lines we observe in their optical spectra are probably formed in the wind of an accretion disk at distances of light days to light years from the central black hole. The variable fraction of the emission lines originates at typical distances of only 1 to 50 light days from the central supermassive black hole. We derived a central black hole mass of M_orbital = 1.8 +/-0.4 x 10^7 M_sun in the Seyfert galaxy Mrk110 assuming the broad emission lines are generated in gas clouds orbiting within an accretion disk. This figure depends on the inclination angle of the accretion disk. Here we report on the detection of gravitational redshifted emission in the variable fraction of the broad emission lines. We derive a central black hole mass of M_grav = 14.0 +/-3.0 x 10^7 M_sun. These measurements are independent on the orientation of the accretion disk. The comparison of both black hole mass estimates allows to determine the projection of the central accretion disk angle i to 21 +/-5 deg. in Mrk110 and therefore the orientation of the spin axis of the central black hole.
Asymmetric-cut variable-incident-angle monochromator
Smither, R. K.; Fernandez, P. B.; Mills, D. M. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Graber, T. J. [Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60637 (United States)
2012-03-15T23:59:59.000Z
A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18 deg. asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage ({Phi}) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation ({Psi}) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation ({Theta}) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.
Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions
Dubin, Paul D.
Small-Angle Neutron Scattering Studies of Charged Carboxyl-Terminated Dendrimers in Solutions Q. R-angle neutron scattering was used to characterize the solution behavior of charged carboxylic acid terminated- copy,16 small-angle X-ray scattering,17 and small-angle neutron scattering (SANS),18-25 have been used
Transverse Spin Physics at COMPASS
Christian Schill; for the COMPASS collaboration
2010-09-08T23:59:59.000Z
The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. Three channels have been analyzed at COMPASS to access the transversity distribution function: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of Lambda hyperons in the final state. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum k_T in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.
Transverse Spin Physics at COMPASS
Federica Sozzi; for the COMPASS Collaboration
2009-02-02T23:59:59.000Z
The study of transverse spin effects is part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. COMPASS investigates the transversity PDFs in semi-inclusive DIS, using a longitudinally polarized muon beam of 160 GeV/c impinging on a transversely polarized target. From 2002 to 2004, data have been collected using a $^6$LiD target transversely polarized. Transversity has been measured using different quark polarimeters: the azimuthal distribution of single hadrons, the azimuthal dependence of the plane containing hadron pairs, and the measurement of the transverse polarization of baryons ($\\Lambda$ hyperons). All the asymmetries have been found to be small, and compatible with zero, a result which has been interpreted as a cancellation between the u and d-quark contributions. In 2007 COMPASS has taken data using a NH$_3$ polarized proton target which will give complementary information on transverse spin effects.
Spin Sum Rules and Polarizabilities
D. Drechsel
2009-10-05T23:59:59.000Z
The Gerasimov-Drell-Hearn sum rule and related dispersive integrals connect real and virtual Compton scattering to inclusive photo- and electroproduction. Being based on universal principles as causality, unitarity, and gauge invariance, these relations provide a unique testing ground to study the internal degrees of freedom that hold a system together. The present contribution reviews the spin-dependent sum rules and cross sections of the nucleon. At small momentum transfer, the data sample information on the long range phenomena (Goldstone bosons and collective resonances), whereas the primary degrees of freedom (quarks and gluons) become visible at large momentum transfer (short distance). The rich body of new data covers a wide range of phenomena from coherent to incoherent processes, and from the generalized spin polarizabilities on the low-energy side to higher twist effects in deep inelastic scattering.
Spin dynamics simulations at AGS
Huang, H.; MacKay, W.W.; Meot, F.; Roser, T.
2010-05-23T23:59:59.000Z
To preserve proton polarization through acceleration, it is important to have a correct model of the process. It has been known that with the insertion of the two helical partial Siberian snakes in the Alternating Gradient Synchrotron (AGS), the MAD model of AGS can not deal with a field map with offset orbit. The stepwise ray-tracing code Zgoubi provides a tool to represent the real electromagnetic fields in the modeling of the optics and spin dynamics for the AGS. Numerical experiments of resonance crossing, including spin dynamics in presence of the snakes and Q-jump, have been performed in AGS lattice models, using Zgoubi. This contribution reports on various results so obtained.
Demand Response Spinning Reserve Demonstration
Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.
2007-05-01T23:59:59.000Z
The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.
Spin Asymmetries at Jurgen Wendland
{ Semi-Inclusive DIS #15; High p t hadron pairs #15; The HERMES RICH detector #15; Conclusion and Outlook; Inclusive DIS allows for the determination of the sum of the quark spins. (With QCD #12;ts to world data #15; HERA is an ep collider with a proton energy of 920GeV and electron energy of 27.5 GeV #15; HERMES
On higher spin partition functions
M. Beccaria; A. A. Tseytlin
2015-06-05T23:59:59.000Z
We observe that the partition function of the set of all free massless higher spins s=0,1,2,3,... in flat space is equal to one: the ghost determinants cancel against the "physical" ones or, equivalently, the (regularized) total number of degrees of freedom vanishes. This reflects large underlying gauge symmetry and suggests analogy with supersymmetric or topological theory. The Z=1 property extends also to the AdS background, i.e. the 1-loop vacuum partition function of Vasiliev theory is equal to 1 (assuming a particular regularization of the sum over spins); this was noticed earlier as a consistency requirement for the vectorial AdS/CFT duality. We find that Z=1 is also true in the conformal higher spin theory (with higher-derivative d^{2s} kinetic terms) expanded near flat or conformally flat S^4 background. We also consider the partition function of free conformal theory of symmetric traceless rank s tensor field which has 2-derivative kinetic term but only scalar gauge invariance in flat 4d space. This non-unitary theory has a Weyl-invariant action in curved background and corresponds to "partially massless" field in AdS_5. We discuss in detail the special case of s=2 (or "conformal graviton"), compute the corresponding conformal anomaly coefficients and compare them with previously found expressions for generic representations of conformal group in 4 dimensions.
On higher spin partition functions
Beccaria, M
2015-01-01T23:59:59.000Z
We observe that the partition function of the set of all free massless higher spins s=0,1,2,3,... in flat space is equal to one: the ghost determinants cancel against the "physical" ones or, equivalently, the (regularized) total number of degrees of freedom vanishes. This reflects large underlying gauge symmetry and suggests analogy with supersymmetric or topological theory. The Z=1 property extends also to the AdS background, i.e. the 1-loop vacuum partition function of Vasiliev theory is equal to 1 (assuming a particular regularization of the sum over spins); this was noticed earlier as a consistency requirement for the vectorial AdS/CFT duality. We find that Z=1 is also true in the conformal higher spin theory (with higher-derivative d^{2s} kinetic terms) expanded near flat or conformally flat S^4 background. We also consider the partition function of free conformal theory of symmetric traceless rank s tensor field which has 2-derivative kinetic term but only scalar gauge invariance in flat space. This non...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amorós, G.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertella, C.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Bondarenko, V. G.; Bondioli, M.; Boonekamp, M.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.
2012-05-01T23:59:59.000Z
A measurement of spin correlation in tt¯ production is reported using data collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 2.1 fb?¹. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. The difference in azimuthal angle between the two charged leptons in the laboratory frame is used to extract the correlation between the top and antitop quark spins. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.40+0.09-0.08, in agreement with the next-to-leading-order standard model prediction. The hypothesis of zero spin correlation is excluded at 5.1 standard deviations.
Pitch Perfect: How Fruit Flies Control their Body Pitch Angle
Whitehead, Samuel C; Canale, Luca; Cohen, Itai
2015-01-01T23:59:59.000Z
Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely-flying D. melanogaster control their body pitch angle against such instability, we perturb them using impulsive mechanical torques and film their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we find that flies correct for pitch deflections of up to 40 degrees in 29 +/- 8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well-described by a linear proportional-integral (PI) controller. Flies initiate this corrective process after only 10 +/- 2 ms, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very large-amplitude pitch perturbations--greater than 150 degrees--providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw an...
Radiation damage studies using small-angle neutron scattering
Albertini, G.; Rustichelli, F. [INFM, Ancona (Italy); Carsughi, F. [INFM, Ancona (Italy). Ist. di Scienze Fisiche; [KFA, Juelich (Germany). Inst. fuer Festkoerperforschung; Coppola, R. [ENEA-Casaccia, Roma (Italy); Stefanon, M. [ENEA, Bologna (Italy)
1996-12-31T23:59:59.000Z
This contribution reviews a number of small-angle neutron scattering (SANS) studies of irradiated metals and steels of relevance to fission and fusion technology. Information obtainable by SANS measurements is recalled with special reference to the determination of the size distribution function of the microstructural inhomogeneities. The selected examples concern studies of the main kinds of radiation defects: voids, precipitates, He-bubbles. Some recent results obtained on structural materials for the first-wall of fusion reactors are also presented.
Spin-dependent transport in a nanopillar non-local spin valve J.-B. Laloe a,, T. Yang a
Otani, Yoshichika
Spin-dependent transport in a nanopillar non-local spin valve J.-B. Lalo¨e a,Ã, T. Yang a , T: Lateral spin-valve Spin current a b s t r a c t We investigate the injection of a pure spin current into a non-magnetic Cu wire in a lateral spin valve. We detect the spin accumulation occurring
Angle-resolved effective potentials for disk-shaped molecules
Thomas Heinemann; Karol Palczynski; Joachim Dzubiella; Sabine H. L. Klapp
2014-10-22T23:59:59.000Z
We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van-der-Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.
Upper bound on parity-violating neutron spin rotation in {sup 4}He
Snow, W. M.; Luo, D.; Walbridge, S. B. [Indiana University/CEEM, 2401 Milo B. Sampson Lane, Bloomington, Indiana 47408 (United States); Bass, C. D.; Bass, T. D.; Mumm, H. P.; Nico, J. S. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Crawford, B. E. [Gettysburg College, 300 North Washington Street, Gettysburg, Pennsylvania 17325 (United States); Gan, K.; Micherdzinska, A. M.; Opper, A. K. [The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Heckel, B. R.; Swanson, H. E. [University of Washington/CENPA, Box 354290, Seattle, Washington 98195 (United States); Markoff, D. M. [North Carolina Central University/TUNL, 1801 Fayetteville Street, Durham, North Carolina 27707 (United States); Sarsour, M. [Georgia State University, 29 Peachtree Center Avenue, Atlanta, Georgia 30303-4106 (United States); Sharapov, E. I. [Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna (Russian Federation); Zhumabekova, V. [Al-Farabi Kazakh National University, Al-Farabi Ave. 71, 050038 Almaty (Kazakhstan)
2011-02-15T23:59:59.000Z
We report an upper bound on parity-violating neutron spin rotation in {sup 4}He. This experiment is the most sensitive search for neutron-weak optical activity yet performed and represents a significant advance in precision in comparison to past measurements in heavy nuclei. The experiment was performed at the NG-6 slow-neutron beamline at the National Institute of Standards and Technology (NIST) Center for Neutron Research. Our result for the neutron spin rotation angle per unit length in {sup 4}He is d{phi}/dz=[+1.7{+-}9.1(stat.){+-}1.4(sys.)]x10{sup -7} rad/m. The statistical uncertainty is smaller than current estimates of the range of possible values of d{phi}/dz in n+{sup 4}He.
Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons
Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bowles, J; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Golembiovskaya, M; Hadjidakis, C; Hartig, M; Hasch, D; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Ivanilov, A; Jackson, H E; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Ma, B -Q; Mahon, D; Makins, N C R; Manaenkov, S I; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Petrosyan, A; Raithel, M; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Seitz, B; Shibata, T -A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stinzing, F; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Wang, S; Yaschenko, S; Ye, Z; Yen, S; Yu, W; Zagrebelnyy, V; Zeiler, D; Zihlmann, B; Zupranski, P
2013-01-01T23:59:59.000Z
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\\sin(\\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.
Transverse target single-spin asymmetry in inclusive electroproduction of charged pions and kaons
The HERMES Collaboration; A. Airapetian; N. Akopov; Z. Akopov; E. C. Aschenauer; W. Augustyniak; R. Avakian; A. Avetissian; E. Avetisyan; S. Belostotski; N. Bianchi; H. P. Blok; A. Borissov; J. Bowles; V. Bryzgalov; J. Burns; M. Capiluppi; G. P. Capitani; E. Cisbani; G. Ciullo; M. Contalbrigo; P. F. Dalpiaz; W. Deconinck; R. De Leo; L. De Nardo; E. De Sanctis; M. Diefenthaler; P. Di Nezza; M. Düren; M. Ehrenfried; G. Elbakian; F. Ellinghaus; R. Fabbri; A. Fantoni; L. Felawka; S. Frullani; D. Gabbert; G. Gapienko; V. Gapienko; G. Gavrilov; V. Gharibyan; F. Giordano; S. Gliske; M. Golembiovskaya; C. Hadjidakis; M. Hartig; D. Hasch; A. Hillenbrand; M. Hoek; Y. Holler; I. Hristova; A. Ivanilov; H. E. Jackson; S. Joosten; R. Kaiser; G. Karyan; T. Keri; E. Kinney; A. Kisselev; V. Korotkov; V. Kozlov; P. Kravchenko; V. G. Krivokhijine; L. Lagamba; L. Lapikás; I. Lehmann; P. Lenisa; A. López Ruiz; W. Lorenzon; B. -Q. Ma; D. Mahon; N. C. R. Makins; S. I. Manaenkov; Y. Mao; B. Marianski; A. Martinez de la Ossa; H. Marukyan; C. A. Miller; Y. Miyachi; A. Movsisyan; V. Muccifora; M. Murray; A. Mussgiller; E. Nappi; Y. Naryshkin; A. Nass; M. Negodaev; W. -D. Nowak; L. L. Pappalardo; R. Perez-Benito; A. Petrosyan; M. Raithel; P. E. Reimer; A. R. Reolon; C. Riedl; K. Rith; G. Rosner; A. Rostomyan; J. Rubin; D. Ryckbosch; Y. Salomatin; F. Sanftl; A. Schäfer; G. Schnell; B. Seitz; T. -A. Shibata; V. Shutov; M. Stancari; M. Statera; E. Steffens; J. J. M. Steijger; J. Stewart; F. Stinzing; S. Taroian; A. Terkulov; R. Truty; A. Trzcinski; M. Tytgat; Y. Van Haarlem; C. Van Hulse; D. Veretennikov; V. Vikhrov; I. Vilardi; S. Wang; S. Yaschenko; Z. Ye; S. Yen; W. Yu; V. Zagrebelnyy; D. Zeiler; B. Zihlmann; P. Zupranski
2013-10-18T23:59:59.000Z
Single-spin asymmetries were investigated in inclusive electroproduction of charged pions and kaons from transversely polarized protons at the HERMES experiment. The asymmetries were studied as a function of the azimuthal angle $\\psi$ about the beam direction between the target-spin direction and the hadron production plane, the transverse hadron momentum relative to the direction of the incident beam, and the Feynman variable $x_F$. The $\\sin(\\psi)$ amplitudes are positive for positive pions and kaons, slightly negative for negative pions and consistent with zero for negative kaons, with particular transverse-momentum but weak $x_F$ dependences. Especially large asymmetries are observed for two small subsamples of events, where also the scattered electron was recorded by the spectrometer.
Nuclear spin noise in NMR revisited
Ferrand, Guillaume; Luong, Michel; Desvaux, Hervé
2015-01-01T23:59:59.000Z
The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite, preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a "bump" or as a "dip" superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparison to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the Spin-Noise and Frequency-Shift Tuning Optima.
Cavity cooling of an ensemble spin system
Christopher J. Wood; Troy W. Borneman; David G. Cory
2014-02-24T23:59:59.000Z
We describe how sideband cooling techniques may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that the coupled angular momentum subspaces of a spin ensemble containing roughly $10^{11}$ electron spins may be polarized in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques should permit efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has recently begun to be explored in further detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.
Generating coherent states of entangled spins
Yu Hongyi; Luo Yu; Yao Wang [Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong (Hong Kong)
2011-09-15T23:59:59.000Z
A coherent state of many spins contains quantum entanglement, which increases with a decrease in the collective spin value. We present a scheme to engineer this class of pure state based on incoherent spin pumping with a few collective raising or lowering operators. In a pumping scenario aimed for maximum entanglement, the steady state of N-pumped spin qubits realizes the ideal resource for the 1{yields}(N/2) quantum telecloning. We show how the scheme can be implemented in a realistic system of atomic spin qubits in an optical lattice. Error analysis shows that high-fidelity state engineering is possible for N{approx}O(100) spins in the presence of decoherence. The scheme can also prepare a resource state for the secret sharing protocol and for the construction of the large-scale Affleck-Kennedy-Lieb-Tasaki state.
Holographic Representation of Higher Spin Gauge Fields
Debajyoti Sarkar; Xiao Xiao
2014-11-17T23:59:59.000Z
Extending the results of \\cite{Heem}, \\cite{KLRS} on the holographic representation of local gauge field operators in anti de Sitter space, here we construct the bulk operators for higher spin gauge fields in the leading order of $\\frac{1}{N}$ expansion. Working in holographic gauge for higher spin gauge fields, we show that gauge field operators with integer spin $s>1$ can be represented by an integration over a ball region, which is the interior region of the spacelike bulk lightcone on the boundary. The construction is shown to be AdS-covariant up to gauge transformations, and the two-point function between higher spin gauge fields and boundary higher spin current exhibit singularities on both bulk and boundary lightcones. We also comment on possible extension to the level of three-point functions and carry out a causal construction for higher spin fields in de Sitter spacetime.
Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive ?0 production
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Holtrop, M; Hyde, C E; Ireland, D G; Isupov, E L; Jawalkar, S S; Jenkins, D; Jo, H S; Joo, K; Keller, D; Khandaker, M; Khetarpal, P; Kim, A; Kimy, W; Klein, A; Klein, F J; Kubarovsky, V; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Kvaltine, N D; Livingston, K; Lu, H Y; MacGregor, I.J. D.; Markov, N; Mayer, M; McAndrew, J; McKinnon, B; Meyer, C A; Micherdzinska, A.M.; Mokeev, V; Moreno, B; Moutarde, H; Munevar, E; Nadel-Turonski, P; Ni, A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Paolone, M; Pappalardo, L; Paremuzyan, R; Park, K; Park, S; Pasyuk, E; Anefalos Pereira, S; Phelps, E; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Raue, B A; Ricco, G; Rimal, D; Ripani, M; Rosner, G; Sabatio, F; Saini, M S; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Seraydaryan, H; Sharabian, Y G; Smith, G D; Sober, D I; Stepanyan, S S; Stepanyan, S; Stoler, P; Strakovsky, I; Strauch, S; Taiuti, M; Tang, W; Taylor, C E; Tkachenko, S; Ungaro, M; Voskanyan, H; Voutier, E; Watts, D; Weinstein, L B; Weygand, D P; Wood, M H; Zana, L; Zhang, J; Zhao, B; Zhao, Z W
2011-10-25T23:59:59.000Z
We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sin ?h amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle ?h of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.
Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas
Cheuk, Lawrence W.
The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable ...
The Raychaudhuri equation for spinning test particles
Mohseni, Morteza
2015-01-01T23:59:59.000Z
We obtain generalized Raychaudhuri equations for spinning test particles corresponding to congruences of particle's world-lines, momentum, and spin. These are physical examples of the Raychaudhuri equation for a non-normalized vector, unit time-like vector, and unit space-like vector. We compute and compare the evolution of expansion-like parameters associated with these congruences for spinning particles confined in the equatorial plane of the Kerr space-time.
Spin-2 particles in gravitational fields
G. Papini
2007-02-01T23:59:59.000Z
We give a solution of the wave equation for massless, or massive spin-2 particles propagating in a gravitational background. The solution is covariant, gauge-invariant and exact to first order in the background gravitational field. The background contribution is confined to a phase factor from which geometrical and physical optics can be derived. The phase also describes Mashhoon's spin-rotation coupling and, in general, the spin-gravity interaction.
Remote quantum gates mediated by spin chains
R. Ronke; I. D'Amico; T. P. Spiller
2010-03-09T23:59:59.000Z
There has been much recent study on the application of spin chains to quantum state transfer and communication. Here we demonstrate that spin chains set up for perfect quantum state transfer can be utilised to generate remote quantum gates, between spin qubits injected at the ends of the chain. The natural evolution of the system across different excitation number sectors generates a maximally-entangling and universal gate between the injected qubits, independent of the length of the chain.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
From October 2012 through September 2013, the second ARM Mobile Facility (AMF2) was deployed on the container ship Spirit, operated by Horizon Lines, for the Marine ARM GPCI* Investigation of Clouds (MAGIC) field campaign. During approximately 20 round trips between Los Angeles, California, and Honolulu, Hawaii, AMF2 obtained continuous on-board measurements of cloud and precipitation, aerosols, and atmospheric radiation; surface meteorological and oceanographic variables; and atmospheric profiles from weather balloons launched every six hours. During two two-week intensive observational periods in January and July 2013, additional instruments were deployed and balloon soundings were be increased to every three hours. These additional data provided a more detailed characterization of the state of the atmosphere and its daily cycle during two distinctly different seasons. The primary objective of MAGIC was to improve the representation of the stratocumulus-to-cumulus transition in climate models. AMF2 data documented the small-scale physical processes associated with turbulence, convection, and radiation in a variety of marine cloud types.
October 22, 1999 Singlets and reflection symmetric spin systems
towers of states. The spinzero tower extends furthest down the energy scale, the spin one tower has spin is often a useful quantum number to classify energy eigenstates of spin systems. An example is the antiferromagnetic Heisenberg Hamiltonian on a bipartite lattice, whose energy levels plotted versus total spin form
A New Spin on Neutrino Quantum Kinetics
Vincenzo Cirigliano; George M. Fuller; Alexey Vlasenko
2015-05-05T23:59:59.000Z
Recent studies have demonstrated that in anisotropic environments a coherent spin-flip term arises in the Quantum Kinetic Equations (QKEs) which govern the evolution of neutrino flavor and spin in hot and dense media. This term can mediate neutrino-antineutrino transformation for Majorana neutrinos and active-sterile transformation for Dirac neutrinos. We discuss the physical origin of the coherent spin-flip term and provide explicit expressions for the QKEs in a two-flavor model with spherical geometry. In this context, we demonstrate that coherent neutrino spin transformation depends on the absolute neutrino mass and Majorana phases.
RHIC spin flipper AC dipole controller
Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.
2011-03-28T23:59:59.000Z
The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.
The Spin Structure of the Nucleon
Filippone, B W; Ji, Xiangdong
2001-01-01T23:59:59.000Z
We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.
The Spin Structure of the Nucleon
B. W. Filippone; Xiangdong Ji
2001-01-19T23:59:59.000Z
We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.
Spin Foam Models from the Tetrad Integration
A. Mikovic
2005-11-15T23:59:59.000Z
We describe a class of spin foam models of four-dimensional quantum gravity which is based on the integration of the tetrad one-forms in the path integral for the Palatini action of General Relativity. In the Euclidian gravity case this class of models can be understood as a modification of the Barrett-Crane spin foam model. Fermionic matter can be coupled by using the path integral with sources for the tetrads and the spin connection, and the corresponding state sum is based on a spin foam where both the edges and the faces are colored independently with the irreducible representations of the spacetime rotations group.
Flipping Photoelectron Spins in Topological Insulators
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Flipping Photoelectron Spins in Topological Insulators Print Inherently strange crystalline materials called 3D topological insulators (TIs) are all the rage in materials science....
Regge phenomenology of pion photoproduction off the nucleon at forward angles
Yu, Byung Geel [Research Institute of Basic Sciences, Korea Aerospace University, Koyang 412-791 (Korea, Republic of); Choi, Tae Keun [Department of Physics, Yonsei University, Wonju 220-710 (Korea, Republic of); Kim, W. [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of)
2011-02-15T23:59:59.000Z
We present a Regge model for pion photoproduction which is basically free of parameters within the framework of the s-channel helicity amplitude. For completeness we take into account axial mesons a{sub 1}(1260), b{sub 1}(1235) and tensor meson a{sub 2}(1320) in addition to the primary {pi}+{rho} exchanges for charged pion photoproduction, while the axial meson h{sub 1}(1170) exchange is added to the model of {omega}+{rho}{sup 0}+b{sub 1} exchanges for the neutral case. The present model deals for the first time with the a{sub 2} and h{sub 1} Regge poles in the s-channel helicity amplitude. For model independence, we use coupling constants of all exchanged mesons determined from empirical decay widths or from the SU(3) relations together with consistency check with existing estimates that are widely accepted in other reaction processes. Based on these coupling constants the simultaneous description of four photoproduction channels is given. Within the Regge regime, s>>4M{sup 2} and -t<2 GeV{sup 2}, cross sections and spin polarization asymmetries at various photon energies are analyzed and results are obtained in better agreement with experimental data without referring to any fitting procedure. The model confirms dominance of the nucleon Born term in the sharp rise of the charged pion cross section at very forward angles, while dominance of the {omega} exchange with the nonsense wrong signature zero leads to the deep dip in the neutral pion cross section. In contrast to existing models, however, our model for the charged pion case shows quite a different production mechanism due to the crucial role of the tensor meson a{sub 2} exchange in the cross section and spin polarization asymmetries. Also the axial meson b{sub 1} exchange is found to give a sizable contribution to the photon polarization asymmetry. In the neutral case, the role of the b{sub 1} is not significant, but the isoscalar h{sub 1} exchange gives an important contribution to the dip-generating mechanism in the photon polarization, showing the isoscalar nature of the process with the {omega}. These findings demonstrate validity of the present model with the prompt use of the tensor meson a{sub 2} and axial meson h{sub 1} for a wider application.
Pure spin currents induced by spin-dependent scattering processes in SiGe quantum well structures
Ganichev, Sergey
Pure spin currents induced by spin-dependent scattering processes in SiGe quantum well structures S-down subbands yielding a pure spin current. In our experiments on SiGe heterostructures the pure spin current recent results obtained on nonmag- netic SiGe nanostructures applying electron spin resonance3,4 ESR
Small angle neutron scattering from high impact polystyrene
Pringle, O.A.
1981-01-01T23:59:59.000Z
High impact polystyrene (HIPS) is a toughened plastic composed of a polystyrene matrix containing a few percent rubber in the form of dispersed 0.1 to 10 micron diameter rubber particles. Some commercial formulations of HIPS include the addition of a few percent mineral oil, which improves the toughness of the plastic. Little is known about the mechanism by which the mineral oil helps toughen the plastic. It is hypothesized that the oil is distributed only in the rubber particles, but whether this hypothesis is correct was not known prior to this work. The size of the rubber particles in HIPS and their neutron scattering length density contrast with the polystyrene matrix cause HIPS samples to scatter neutrons at small angles. The variation of this small angle neutron scattering (SANS) signal with mineral oil content has been used to determine the location of the oil in HIPS. The SANS spectrometer at the University of Missouri Research Reactor Facility (MURR) was used to study plastic samples similar in composition to commercial HIPS. The MURR SANS spectrometer is used to study the small angle scattering of a vertical beam of 4.75 A neutrons from solid and liquid samples. The scattered neutrons are detected in a 54 x 60 cm/sup 2/ position sensitive detector designed and built at MURR. A series of plastic samples of varying rubber and oil content and different rubber domain sizes and shapes were examined on the MURR SANS spectrometer. Analysis of the scattering patterns showed that the mineral oil is about eight to ten times more likely to be found in the rubber particles than in the polystyrene matrix. This result confirmed the hypothesis that the mineral oil is distributed primarily in the rubber particles.
Europium oxide as a perfect electron spin filter
Santos, Tiffany S. (Tiffany Suzanne), 1980-
2007-01-01T23:59:59.000Z
Essential to the emergence of spin-based electronics is a source of highly polarized electron spins. Conventional ferromagnets have at best a spin polarization P-50%. Europium monoxide is a novel material capable of ...
Transverse Spin Effects at COMPASS
C. Schill
2009-09-29T23:59:59.000Z
The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a transversely polarized 6LiD target. In 2007, a transversely polarized NH3 target was used. Three different channels to access the transversity distribution function have been analyzed: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of lambda hyperons in the final state. Transverse quark momentum effects in a transversely polarized nucleon have been investigated by measuring the Sivers distribution function. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries using spin-averaged 6LiD data.
Transverse Spin Effects at COMPASS
H. Wollny
2009-02-03T23:59:59.000Z
Single spin asymmetries in semi-inclusive deep-inelastic scattering off transversely polarized nucleon targets have been under intense experimental investigation over the past few years. They provide new insights into QCD and the nucleon structure. For instance, they allow the determination of the third yet-unknown leading-twist quark distribution function $\\Delta_{T}q(x)$, the transversity distribution. Additionally, they give insight into the parton transverse momentum distribution and angular momentum. The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. In the years 2002-2004 data were collected scattering a 160 GeV muon beam on a transversely polarized deuteron target. In 2007, additional data were collected on a transversely polarized proton target. New results from the analysis of the proton data will be presented. A different but not less important insight into the nucleon structure might be given by the Sivers asymmetry. This angular dependence of the cross-section arises from an intrinsic asymmetry in the parton transverse momentum distribution. The Sivers function is tightly related to the total angular momentum carried by the quarks in the nucleon. New COMPASS results for the Sivers asymmetry of the proton will be shown.
Magnetic Monopoles in Spin Ice
Claudio Castelnovo; Roderich Moessner; Shivaji L. Sondhi
2007-10-31T23:59:59.000Z
Electrically charged particles, such as the electron, are ubiquitous. By contrast, no elementary particles with a net magnetic charge have ever been observed, despite intensive and prolonged searches. We pursue an alternative strategy, namely that of realising them not as elementary but rather as emergent particles, i.e., as manifestations of the correlations present in a strongly interacting many-body system. The most prominent examples of emergent quasiparticles are the ones with fractional electric charge e/3 in quantum Hall physics. Here we show that magnetic monopoles do emerge in a class of exotic magnets known collectively as spin ice: the dipole moment of the underlying electronic degrees of freedom fractionalises into monopoles. This enables us to account for a mysterious phase transition observed experimentally in spin ice in a magnetic field, which is a liquid-gas transition of the magnetic monopoles. These monopoles can also be detected by other means, e.g., in an experiment modelled after the celebrated Stanford magnetic monopole search.
Charge and spin topological insulators
Kopaev, Yu. V., E-mail: kopaev@sci.lebedev.ru; Gorbatsevich, A. A.; Belyavskii, V. I. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
2011-09-15T23:59:59.000Z
The topologically nontrivial states of matter-charge and spin topological insulators, which exhibit, respectively, properties of the integer quantum Hall effect and the quantum spin Hall effect-are discussed. The topological characteristics (invariant with respect to weak adiabatic changes in the Hamiltonian parameters) which lead to such states are considered. The model of a 2D hexagonal lattice having symmetries broken with respect to time reversal and spatial inversion which was proposed by Haldane and marked the beginning of unprecedented activity in the study of topologically nontrivial states is discussed. This model relates the microscopic nature of the symmetry breaking with respect to the time reversal to the occurrence of spontaneous orbital currents which circulate within a unit cell. Such currents become zero upon summation over the unit cell, but they may form spreading current states at the surface which are similar to the edge current states under the quantum Hall effect. The first model of spontaneous currents (exciton insulator model) is considered, and the possibility of implementing new topologically nontrivial states in this model is discussed.
Hysteretic Optimization For Spin Glasses
B. Goncalves; S. Boettcher
2007-12-10T23:59:59.000Z
The recently proposed Hysteretic Optimization (HO) procedure is applied to the 1D Ising spin chain with long range interactions. To study its effectiveness, the quality of ground state energies found as a function of the distance dependence exponent, $\\sigma$, is assessed. It is found that the transition from an infinite-range to a long-range interaction at $\\sigma=0.5$ is accompanied by a sharp decrease in the performance . The transition is signaled by a change in the scaling behavior of the average avalanche size observed during the hysteresis process. This indicates that HO requires the system to be infinite-range, with a high degree of interconnectivity between variables leading to large avalanches, in order to function properly. An analysis of the way auto-correlations evolve during the optimization procedure confirm that the search of phase space is less efficient, with the system becoming effectively stuck in suboptimal configurations much earlier. These observations explain the poor performance that HO obtained for the Edwards-Anderson spin glass on finite-dimensional lattices, and suggest that its usefulness might be limited in many combinatorial optimization problems.
Solid angle and surface density as criticality parameters
Thomas, J.T.
1980-10-01T23:59:59.000Z
Two methods often used to establish nuclear criticality safety limits for operations with fissile materials are the surface density and solid angle techniques. The two methods are used as parameters to express experimental and validated calculations of critical configurations. It is demonstrated that each method can represent critical arrangements of subcritical units and that there can be established a one-to-one correspondence between them. The analyses further show that the effect on an array neutron multiplication factor of perturbations to the array can be reliably estimated and that each form of fissile material and unit shape has a specific representation.
Material loss angles from direct measurements of broadband thermal noise
Principe, Maria; Pierro, Vincenzo; DeSalvo, Riccardo; Taurasi, Ilaria; Villar, Akira E; Black, Eric D; Libbrecht, Kenneth G; Michel, Christophe; Morgado, Nazario; Pinard, Laurent
2015-01-01T23:59:59.000Z
We estimate the loss angles of the materials currently used in the highly reflective test-mass coatings of interferometric detectors of gravitational waves, namely Silica, Tantala, and Ti-dop ed Tantala, from direct measurement of coating thermal noise in an optical interferometer testbench, the Caltech TNI. We also present a simple predictive theory for the material properties of amorphous glassy oxide mixtures, which gives results in good agreement with our measurements on Ti-doped Tantala. Alternative measure ment methods and results are reviewed, and some critical issues are discussed.
Single-parameter spin-pumping in driven metallic rings with spin-orbit coupling
Ramos, J. P.; Apel, V. M. [Departamento de Física, Universidad Católica del Norte, Angamos 0610, Casilla 1280, Antofagasta (Chile); Foa Torres, L. E. F. [Instituto de Física Enrique Gaviola (CONICET) and FaMAF, Universidad Nacional de Córdoba, Ciudad Universitaria 5000, Córdoba (Argentina); Orellana, P. A. [Departamento de Física, Universidad Técnica Federico Santa María, Avenida Vicuña Mackenna 3939, San Joaquin, Santiago (Chile)
2014-03-28T23:59:59.000Z
We consider the generation of a pure spin-current at zero bias voltage with a single time-dependent potential. To such end we study a device made of a mesoscopic ring connected to electrodes and clarify the interplay between a magnetic flux, spin-orbit coupling, and non-adiabatic driving in the production of a spin and electrical current. By using Floquet theory, we show that the generated spin to charge current ratio can be controlled by tuning the spin-orbit coupling.
Investigating the angle or response and maximum stability of a cohesive granular pile
Nowak, Sara Alice, 1982-
2004-01-01T23:59:59.000Z
In this thesis, I investigate the static and dynamic properties of a granular heap made cohesive by an interstitial fluid. I present the results of experimental work measuring the maximum angle of stability and the angle ...
Correlation of Oil-Water and Air-Water Contact Angles of Diverse...
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Oil-Water and Air-Water Contact Angles of Diverse Silanized Surfaces and Relationship to Fluid Interfacial Correlation of Oil-Water and Air-Water Contact Angles of Diverse...
Spin Transport in non-inertial frame
Debashree Chowdhury; B. Basu
2014-04-09T23:59:59.000Z
The influence of acceleration and rotation on spintronic applications is theoretically investigated. In our formulation, considering a Dirac particle in a non-inertial frame, different spin related aspects are studied. The spin current appearing due to the inertial spin-orbit coupling (SOC) is enhanced by the interband mixing of the conduction and valence band states. Importantly, one can achieve a large spin current through the $\\vec{k}. \\vec{p}$ method in this non-inertial frame. Furthermore, apart from the inertial SOC term due to acceleration, for a particular choice of the rotation frequency, a new kind of SOC term can be obtained from the spin rotation coupling (SRC). This new kind of SOC is of Dresselhaus type and controllable through the rotation frequency. In the field of spintronic applications, utilizing the inertial SOC and SRC induced SOC term, theoretical proposals for the inertial spin filter, inertial spin galvanic effect are demonstrated. Finally, one can tune the spin relaxation time in semiconductors by tuning the non-inertial parameters.
Coherent Manipulation of Coupled Electron Spins in
Petta, Jason
to control quantum systems in the solid state is a major challenge of modern condensed-matter physics (5, 6. Gossard3 We demonstrated coherent control of a quantum two-level system based on two-electron spin states) based on two-electron spin states (14) and demonstrate coherent control of this system through the use
Spacetime Warps for Spinning Particles Possible?
T. Dudas
2002-01-04T23:59:59.000Z
By incorporating spinning particles into the framework of classical General Relativity, the theory is changed insofar, as, though using holonome coordinates, the connexion becomes asymmetrical. This implies, that partial derivatives do not commute any longer. Hence, the class of functions under consideration has to be extended. A non-minimal extension leads to the possibility of spacetime warps for spinning particles.
Tidal deformations of a spinning compact object
Paolo Pani; Leonardo Gualtieri; Andrea Maselli; Valeria Ferrari
2015-03-25T23:59:59.000Z
The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole moments of the central object, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.
Information storage capacity of discrete spin systems
Beni Yoshida
2012-12-24T23:59:59.000Z
Understanding the limits imposed on information storage capacity of physical systems is a problem of fundamental and practical importance which bridges physics and information science. There is a well-known upper bound on the amount of information that can be stored reliably in a given volume of discrete spin systems which are supported by gapped local Hamiltonians. However, all the previously known systems were far below this theoretical bound, and it remained open whether there exists a gapped spin system that saturates this bound. Here, we present a construction of spin systems which saturate this theoretical limit asymptotically by borrowing an idea from fractal properties arising in the Sierpinski triangle. Our construction provides not only the best classical error-correcting code which is physically realizable as the energy ground space of gapped frustration-free Hamiltonians, but also a new research avenue for correlated spin phases with fractal spin configurations.
Electric field induced spin-polarized current
Murakami, Shuichi; Nagaosa, Naoto; Zhang, Shoucheng
2006-05-02T23:59:59.000Z
A device and a method for generating an electric-field-induced spin current are disclosed. A highly spin-polarized electric current is generated using a semiconductor structure and an applied electric field across the semiconductor structure. The semiconductor structure can be a hole-doped semiconductor having finite or zero bandgap or an undoped semiconductor of zero bandgap. In one embodiment, a device for injecting spin-polarized current into a current output terminal includes a semiconductor structure including first and second electrodes, along a first axis, receiving an applied electric field and a third electrode, along a direction perpendicular to the first axis, providing the spin-polarized current. The semiconductor structure includes a semiconductor material whose spin orbit coupling energy is greater than room temperature (300 Kelvin) times the Boltzmann constant. In one embodiment, the semiconductor structure is a hole-doped semiconductor structure, such as a p-type GaAs semiconductor layer.
Environment Assisted Metrology with Spin Qubit
P. Cappellaro; G. Goldstein; J. S. Hodges; L. Jiang; J. R. Maze; A. S. Sørensen; M. D. Lukin
2012-01-12T23:59:59.000Z
We investigate the sensitivity of a recently proposed method for precision measurement [Phys. Rev. Lett. 106, 140502 (2011)], focusing on an implementation based on solid-state spin systems. The scheme amplifies a quantum sensor response to weak external fields by exploiting its coupling to spin impurities in the environment. We analyze the limits to the sensitivity due to decoherence and propose dynamical decoupling schemes to increase the spin coherence time. The sensitivity is also limited by the environment spin polarization; therefore we discuss strategies to polarize the environment spins and present a method to extend the scheme to the case of zero polarization. The coherence time and polarization determine a figure of merit for the environment's ability to enhance the sensitivity compared to echo-based sensing schemes. This figure of merit can be used to engineer optimized samples for high-sensitivity nanoscale magnetic sensing, such as diamond nanocrystals with controlled impurity density.
anomalous spin waves: Topics by E-print Network
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branches of wave dispersion: spin-electromagnetic plasma waves and self-consistent spin waves. Propagation of neutron beams through quantum plasmas is also considered....
Dynamic Switching of the Spin Circulation in Tapered Magnetic...
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Dynamic Switching of the Spin Circulation in Tapered Magnetic Nanodisks Dynamic Switching of the Spin Circulation in Tapered Magnetic Nanodisks Print Monday, 22 April 2013 12:09...
Flat Lens Criterion by Small-Angle Phase
Ott, Peter; Lezec, Henri J; Chau, Kenneth J
2015-01-01T23:59:59.000Z
We show that a classical imaging criterion based on angular dependence of small-angle phase can be applied to any system composed of planar, uniform media to determine if it is a flat lens capable of forming a real paraxial image and to estimate the image location. The real paraxial image location obtained by this method shows agreement with past demonstrations of far-field flat-lens imaging and can even predict the location of super-resolved images in the near-field. The generality of this criterion leads to several new predictions: flat lenses for transverse-electric polarization using dielectric layers, a broadband flat lens working across the ultraviolet-visible spectrum, and a flat lens configuration with an image plane located up to several wavelengths from the exit surface. These predictions are supported by full-wave simulations. Our work shows that small-angle phase can be used as a generic metric to categorize and design flat lenses.
Hydrophilic property by contact angle change of ion implanted polycarbonate
Lee, Chan Young; Kil, Jae Keun [Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, P.O. Box 105, Yuseong, Daejeon, 305-600 (Korea, Republic of); R and D Team, Accel Korea, 146-1 Pyeongchon-dong Daeduck-gu Daejeon (Korea, Republic of)
2008-02-15T23:59:59.000Z
In this study, ion implantation was performed onto a polymer, polycarbonate (PC), in order to investigate surface hydrophilic property through contact angle measurement. PC was irradiated with N, Ar, and Xe ions at the irradiation energy of 20-50 keV and the dose range of 5x10{sup 15}, 1x10{sup 16}, 7x10{sup 16} ions/cm{sup 2}. The contact angle of water was estimated by means of the sessile drop method and was reduced with increasing fluence and ion mass but increased with increasing implanted energy. The changes of chemical and structural properties are discussed in view of Furier transform infrared and x-ray photoelectron spectroscopy, which shows increasing C-O bonding and C-C bonding. The surface roughness examined by atomic force microscopy measurement changed smoothly from 3.59 to 2.22 A as the fluence increased. It is concluded that the change in wettability may be caused by surface carbonization and oxidation as well as surface roughness.
G$^0$ Electronics and Data Acquisition (Forward-Angle Measurements)
D. Marchand; J. Arvieux; L. Bimbot; A. Biselli; J. Bouvier; H. Breuer; R. Clark; J. -C. Cuzon; M. Engrand; R. Foglio; C. Furget; X. Grave; B. Guillon; H. Guler; P. M. King; S. Kox; J. Kuhn; Y. Ky; J. Lachniet; J. Lenoble; E. Liatard; J. Liu; E. Munoz; J. Pouxe; G. Quéméner; B. Quinn; J. -S. Réal; O. Rossetto; R. Sellem
2007-03-15T23:59:59.000Z
The G$^0$ parity-violation experiment at Jefferson Lab (Newport News, VA) is designed to determine the contribution of strange/anti-strange quark pairs to the intrinsic properties of the proton. In the forward-angle part of the experiment, the asymmetry in the cross section was measured for $\\vec{e}p$ elastic scattering by counting the recoil protons corresponding to the two beam-helicity states. Due to the high accuracy required on the asymmetry, the G$^0$ experiment was based on a custom experimental setup with its own associated electronics and data acquisition (DAQ) system. Highly specialized time-encoding electronics provided time-of-flight spectra for each detector for each helicity state. More conventional electronics was used for monitoring (mainly FastBus). The time-encoding electronics and the DAQ system have been designed to handle events at a mean rate of 2 MHz per detector with low deadtime and to minimize helicity-correlated systematic errors. In this paper, we outline the general architecture and the main features of the electronics and the DAQ system dedicated to G$^0$ forward-angle measurements.
The Provision of IP Crossing Angles for the SSC
Ritson, David M
2003-07-11T23:59:59.000Z
Luminosity is to be produced at the SSC collider by crossing with finite angle the counter circulating proton beams at each interaction point (IP). Such a crossing angle introduces unwanted dispersion in the high beta triplet quadrupoles adjacent to the IPs which must be corrected out. they propose to produce variable crossing conditions at each IP with local steering dipoles adjusted to give required slopes and displacements for each IP. The anomalous dispersion introduced by these orbit displacements will be corrected in the arcs (dispersive region) just prior to entry and exit into the IRs with opposite polarity quadrupole pairs separated by 90{sup o} in phase, a late correction scheme. Such pairs cause minimal change to the betatron functions but produce dispersion that can be set to cancel the anomalous dispersion. The IR design is such that the phase advance between correctors and the IP triplet gives efficient full local anomalous dispersion cancellation. The proposed system is to be formed from standard SSC corrector elements and will provide the range of crossing conditions required for collision optics and for separating the beams at injection.
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
Gevorgyan, Sergey [JINR; Gasparian, Ashot H. [North Carolina Ag. and Tech. St. U; Gan, Liping [University of North Carolina at Wilmington; Larin, Ilya F. [ITEP, Moscow; Khandaker, Mahbubul A. [Idaho State U
2012-01-01T23:59:59.000Z
Recent advances in the photon tagging facilities together with the novel, high-resolution fast calorimetry make it possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, in the framework of the Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and the Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, {sup 16}O, and from an unclosed shell nucleus, {sup 12}C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
S. Gevorkyan; A. Gasparian; L. Gan; I. Larin; M. Khandaker
2009-08-10T23:59:59.000Z
Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, based on the framework of Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, 16^O, and from an unclosed shell nucleus, 12^C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.
Rotation Angle for the Optimum Tracking of One-Axis Trackers
Marion, W. F.; Dobos, A. P.
2013-07-01T23:59:59.000Z
An equation for the rotation angle for optimum tracking of one-axis trackers is derived along with equations giving the relationships between the rotation angle and the surface tilt and azimuth angles. These equations are useful for improved modeling of the solar radiation available to a collector with tracking constraints and for determining the appropriate motor revolutions for optimum tracking.
UNIVERSITY of CALIFORNIA INVESTIGATION OF HOW ANGLE OF ATTACK AFFECTS ROTOR SPEED
Belanger, David P.
-pitch blades is tested in UCSC's wind tunnel. The turbine is used to test how varying the blade angle affects the turbine's rotational speed at different wind speeds. The data are used to determine how the blade angle 27 Appendix A Wind Turbine Data 29 Appendix B Converting Blade Pitch to Needle Angle 33 Appendix C
A new method for analyzing collimation angle of neutron Soller collimator
Jian-Bo Gao; Yun-Tao Liu; Dong-Feng Chen
2015-03-18T23:59:59.000Z
A new method for analyzing collimation angle of neutron Soller collimator is described. Gaussian distribution formula is used to define the angle distribution function of neutron source and neutron transmission function of Soller collimator. A relationship between FWHM of collimator rocking curve and collimation angle is derived.
A new method for analyzing collimation angle of neutron Soller collimator
Gao, Jian-Bo; Chen, Dong-Feng
2015-01-01T23:59:59.000Z
A new method for analyzing collimation angle of neutron Soller collimator is described. Gaussian distribution formula is used to define the angle distribution function of neutron source and neutron transmission function of Soller collimator. A relationship between FWHM of collimator rocking curve and collimation angle is derived.
hal-00154048,version1-12Jun2007 The new very small angle neutron scattering
Boyer, Edmond
hal-00154048,version1-12Jun2007 The new very small angle neutron scattering spectrometer The design and characteristics of the new very small angle neutron scattering spectrometer under construction in order to fill the gap between light scattering and classical small angle neutron scattering (SANS
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The higher spin Laplace operator
Hendrik De Bie; David Eelbode; Matthias Roels
2015-01-24T23:59:59.000Z
This paper deals with a certain class of second-order conformally invariant operators acting on functions taking values in particular (finite-dimensional) irreducible representations of the orthogonal group. These operators can be seen as a generalisation of the Laplace operator to higher spin as well as a second order analogue of the Rarita-Schwinger operator. To construct these operators, we will use the framework of Clifford analysis, a multivariate function theory in which arbitrary irreducible representations for the orthogonal group can be realised in terms of polynomials satisfying a system of differential equations. As a consequence, the functions on which this particular class of operators act are functions taking values in the space of harmonics homogeneous of degree k. We prove the ellipticity of these operators and use this to investigate their kernel, focusing on both polynomial solutions and the fundamental solution.
Electron Spin Precession at CEBAF
Douglas Higinbotham
2009-08-01T23:59:59.000Z
The nuclear physics experiments at the Thomas Jefferson National Accelerator Facility often require longitudinally polarized electrons to be simultaneously delivered to three experimental halls. The degree of longitudinal polarization to each hall varies as function of the accelerator settings, making it challenging in certain situations to deliver a high degree of longitudinal polarization to all the halls simultaneously. Normally, the degree of longitudinal polarization the halls receive is optimized by changing the initial spin direction at the beginning of the machine with a Wien filter. Herein, it is shown that it is possible to further improve the degree of longitudinal polarization for multiple experimental halls by redistributing the energy gain of the CEBAF linacs while keeping the total energy gain fixed.
Electron Spin Precession at CEBAF
Higinbotham, Douglas
2009-01-01T23:59:59.000Z
The nuclear physics experiments at the Thomas Jefferson National Accelerator Facility often require longitudinally polarized electrons to be simultaneously delivered to three experimental halls. The degree of longitudinal polarization to each hall varies as function of the accelerator settings, making it challenging in certain situations to deliver a high degree of longitudinal polarization to all the halls simultaneously. Normally, the degree of longitudinal polarization the halls receive is optimized by changing the initial spin direction at the beginning of the machine with a Wien filter. Herein, it is shown that it is possible to further improve the degree of longitudinal polarization for multiple experimental halls by redistributing the energy gain of the CEBAF linacs while keeping the total energy gain fixed.
Sinitsyn, NA; Hankiewicz, EM; Teizer, Winfried; Sinova, Jairo.
2004-01-01T23:59:59.000Z
new avenues in spintronics research and transport phenomena which may meet the first challenge. The intrinsic spin-Hall effect consists of a dissipationless spin-current contribution generated perpendicular to the driv- ing electric field whenever... that the dc z-component spin-current Hall response to a driv- ing internal electric field, jsz=sxyspinEy, in the clean limit has a universal value whenever the two Rashba split bands are occupied (the usual case), sxyspin=e /8p, and vanishes linearly...
Velarde Ruiz Esparza, Luis A.; Wang, Hongfei
2013-10-14T23:59:59.000Z
The relative phase and amplitude ratio between the ssp and ppp polarization combinations of the vibrational sum-frequency generation (SFG) response can be uniquely and accurately determined by the polarization null angle (PNA) method. In this report we show that PNA measurements of the -CN vibration in the 4-n pentyl-4'-cyanoterphenyl (5CT) Langmuir monolayer at the air/water interface yields ssp and ppp response of the same phase, while those in the 4-n-octyl-4'cyanobiphenyl (8CB) Langmuir monolayer have the opposite phase. Accordingly, the -CN group in the 5CT monolayer is tilted around 25+/-2 from the interface normal, while that in the 8CB is tilted around 57+/-2, consistent with the significant differences in the phase diagrams and hydrogen bonding SFG spectra of the two Langmuir monolayers as reported in the literature. These results also demonstrate that in SFG studies the relative phase information of the different polarization combinations, especially for the ssp and ppp, is important in the unique determination of the tilt angle and conformation of a molecular group at the interface.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zachariou, Nicholas; et. al.,
2015-05-01T23:59:59.000Z
The beam-spin asymmetry, Sigma, for the reaction ?d-->pn has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins, between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, thetac.m., between 25degrees and 160degrees. These are the first measurements of beam-spin asymmetries at thetac.m.=90degrees for photon-beam energies above 1.6 GeV, and the first measurements for angles other than thetac.m.=90degrees. The angular and energy dependence of Sigma is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition regionmore »between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.« less
Zachariou, Nicholas; Ivanov, Nikolay Ya; Sargsian, Misak M; Avakian, Robert; Feldman, Gerald; Nadel-Turonski, Pawel; Adhikari, K P; Adikaram, D; Anderson, M D; Pereira, S Anefalos; Avakian, H; Badui, R A; Baltzell, N A; Battaglieri, M; Baturin, V; Bedlinskiy, I; Biselli, A S; Briscoe, W J; Brooks, W K; Burkert, V D; Cao, T; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Compton, N; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Elouadrhiri, L; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Forest, T A; Fradi, A; Gevorgyan, N; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Glazier, D I; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Hafidi, K; Hanretty, C; Harrison, N; Hattawy, M; Hicks, K; Ho, D; Holtrop, M; Hughes, S M; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jiang, H; Jo, H S; Joo, K; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Kim, W; Klein, F J; Kubarovsky, V; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; Markov, N; Mattione, P T; McKinnon, B; Mineeva, T; Mirazita, M; Mokeeev, V I; Montgomery, R A; Moutarde, H; Camacho, C Munoz; Net, L A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Phelps, W; Phillips, J J; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Procureur, S; Prok, Y; Protopopescu, D; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Rossi, P; Roy, P; Sabatié, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Senderovich, I; Sharabian, Y G; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Stepanyan, S; Strauch, S; Sytnik, V; Taiuti, M; Tian, Ye; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Watts, D; Wei, X; Wood, M H; Zana, L; Zhang, J; Zhao, Z W; Zonta, I
2015-01-01T23:59:59.000Z
The beam-spin asymmetry, $\\Sigma$, for the reaction $\\gamma d\\rightarrow pn$ has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, $\\theta_{c.m.}$, between $25^\\circ$ and $160^\\circ$. These are the first measurements of beam-spin asymmetries at $\\theta_{c.m.}=90^\\circ$ for photon-beam energies above 1.6 GeV, and the first measurements for angles other than $\\theta_{c.m.}=90^\\circ$. The angular and energy dependence of $\\Sigma$ is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zachariou, Nicholas [University of South Carolina; et. al.,
2015-05-01T23:59:59.000Z
The beam-spin asymmetry, Sigma, for the reaction ?d-->pn has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins, between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, thetac.m., between 25degrees and 160degrees. These are the first measurements of beam-spin asymmetries at thetac.m.=90degrees for photon-beam energies above 1.6 GeV, and the first measurements for angles other than thetac.m.=90degrees. The angular and energy dependence of Sigma is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.
Nicholas Zachariou; Yordanka Ilieva; Nikolay Ya. Ivanov; Misak M Sargsian; Robert Avakian; Gerald Feldman; Pawel Nadel-Turonski; K. P. Adhikari; D. Adikaram; M. D. Anderson; S. Anefalos Pereira; H. Avakian; R. A. Badui; N. A. Baltzell; M. Battaglieri; V. Baturin; I. Bedlinskiy; A. S. Biselli; W. J. Briscoe; W. K. Brooks; V. D. Burkert; T. Cao; D. S. Carman; A. Celentano; S. Chandavar; G. Charles; L. Colaneri; P. L. Cole; N. Compton; M. Contalbrigo; O. Cortes; V. Crede; A. D'Angelo; R. De Vita; E. De Sanctis; A. Deur; C. Djalali; R. Dupre; H. Egiyan; A. El Alaoui; L. El Fassi; L. Elouadrhiri; G. Fedotov; S. Fegan; A. Filippi; J. A. Fleming; T. A. Forest; A. Fradi; N. Gevorgyan; Y. Ghandilyan; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; D. I. Glazier; E. Golovatch; R. W. Gothe; K. A. Griffioen; M. Guidal; K. Hafidi; C. Hanretty; N. Harrison; M. Hattawy; K. Hicks; D. Ho; M. Holtrop; S. M. Hughes; D. G. Ireland; B. S. Ishkhanov; E. L. Isupov; H. Jiang; H. S. Jo; K. Joo; D. Keller; G. Khachatryan; M. Khandaker; A. Kim; W. Kim; F. J. Klein; V. Kubarovsky; P. Lenisa; K. Livingston; H. Y. Lu; I . J . D. MacGregor; N. Markov; P. T. Mattione; B. McKinnon; T. Mineeva; M. Mirazita; V. I. Mokeeev; R. A. Montgomery; H. Moutarde; C. Munoz Camacho; L. A. Net; S. Niccolai; G. Niculescu; I. Niculescu; M. Osipenko; A. I. Ostrovidov; K. Park; E. Pasyuk; W. Phelps; J. J. Phillips; S. Pisano; O. Pogorelko; S. Pozdniakov; J. W. Price; S. Procureur; Y. Prok; D. Protopopescu; A. J. R. Puckett; M. Ripani; A. Rizzo; G. Rosner; P. Rossi; P. Roy; F. Sabatié; C. Salgado; D. Schott; R. A. Schumacher; E. Seder; I. Senderovich; Y. G. Sharabian; Iu. Skorodumina; G. D. Smith; D. I. Sober; D. Sokhan; N. Sparveris; S. Stepanyan; S. Strauch; V. Sytnik; M. Taiuti; Ye Tian; M. Ungaro; H. Voskanyan; E. Voutier; N. K. Walford; D. Watts; X. Wei; M. H. Wood; L. Zana; J. Zhang; Z. W. Zhao; I. Zonta; for the CLAS collaboration
2015-03-18T23:59:59.000Z
The beam-spin asymmetry, $\\Sigma$, for the reaction $\\gamma d\\rightarrow pn$ has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, $\\theta_{c.m.}$, between $25^\\circ$ and $160^\\circ$. These are the first measurements of beam-spin asymmetries at $\\theta_{c.m.}=90^\\circ$ for photon-beam energies above 1.6 GeV, and the first measurements for angles other than $\\theta_{c.m.}=90^\\circ$. The angular and energy dependence of $\\Sigma$ is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition region between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zachariou, N.; Ilieva, Y.; Ivanov, N. Ya.; Sargsian, M. M.; Avakian, R.; Feldman, G.; Nadel-Turonski, P.
2015-05-01T23:59:59.000Z
The beam-spin asymmetry, ?, for the reaction ?d???pn has been measured using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility (JLab) for six photon-energy bins, between 1.1 and 2.3 GeV, and proton angles in the center-of-mass frame, ?c.m., between 25° and 160°. These are the first measurements of beam-spin asymmetries at ?c.m.=90° for photon-beam energies above 1.6 GeV, and the first measurements for angles other than ?c.m.=90°. The angular and energy dependence of ? is expected to aid in the development of QCD-based models to understand the mechanisms of deuteron photodisintegration in the transition regionmore »between hadronic and partonic degrees of freedom, where both effective field theories and perturbative QCD cannot make reliable predictions.« less
S. Kumano
2015-04-21T23:59:59.000Z
Spin-physics projects at J-PARC are explained by including future possibilities. J-PARC is the most-intense hadron-beam facility in the high-energy region above multi-GeV, and spin physics will be investigated by using secondary beams of kaons, pions, neutrinos, muons, and antiproton as well as the primary-beam proton. In particle physics, spin topics are on muon $g-2$, muon and neutron electric dipole moments, and time-reversal violation experiment in a kaon decay. Here, we focus more on hadron-spin physics as for future projects. For example, generalized parton distributions (GPDs) could be investigated by using pion and proton beams, whereas they are studied by the virtual Compton scattering at lepton facilities. The GPDs are key quantities for determining the three-dimensional picture of hadrons and for finding the origin of the nucleon spin including partonic orbital-angular-momentum contributions. In addition, polarized parton distributions and various hadron spin topics should be possible by using the high-momentum beamline. The strangeness contribution to the nucleon spin could be also investigated in principle with the neutrino beam with a near detector facility.
Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India) [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Brunner, S. [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)] [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ganesh, R. [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India)] [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Jenko, F. [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)
2014-03-15T23:59:59.000Z
This paper presents effects of finite ballooning angles on linear ion temperature gradient (ITG) driven mode and associated heat and momentum flux in Gyrokinetic flux tube simulation GENE. It is found that zero ballooning angle is not always the one at which the linear growth rate is maximum. The ITG mode acquires a short wavelength (SW) branch (k{sub ?}?{sub i}?>?1) when growth rates maximized over all ballooning angles are considered. However, the SW branch disappears on reducing temperature gradient showing characteristics of zero ballooning angle SWITG in case of extremely high temperature gradient. Associated heat flux is even with respect to ballooning angle and maximizes at nonzero ballooning angle while the parallel momentum flux is odd with respect to the ballooning angle.
IR OPTICS MEASUREMENT WITH LINEAR COUPLING'S ACTION-ANGLE PARAMETERIZATION.
LUO, Y.; BAI, M.; PILAT, R.; SATOGATA, T.; TRBOJEVIC, D.
2005-05-16T23:59:59.000Z
A parameterization of linear coupling in action-angle coordinates is convenient for analytical calculations and interpretation of turn-by-turn (TBT) beam position monitor (BPM) data. We demonstrate how to use this parameterization to extract the twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of the long IR drift region. The example of TBT BPM analysis was acquired at the Relativistic Heavy Ion Collider (RHIC), using an AC dipole to excite a single eigenmode. Besides the full treatment, a fast estimate of beta*, the beta function at the interaction point (IP), is provided, along with the phase advance between these BPMs. We also calculate and measure the waist of the beta function and the local optics.
Two wide-angle imaging neutral-atom spectrometers
McComas, D.J.
1997-12-31T23:59:59.000Z
The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission provides a new capability for stereoscopically imaging the magnetosphere. By imaging the charge exchange neutral atoms over a broad energy range (1 < E , {approximately} 100 keV) using two identical instruments on two widely-spaced high-altitude, high-inclination spacecraft, TWINS will enable the 3-dimensional visualization and the resolution of large scale structures and dynamics within the magnetosphere for the first time. These observations will provide a leap ahead in the understanding of the global aspects of the terrestrial magnetosphere and directly address a number of critical issues in the ``Sun-Earth Connections`` science theme of the NASA Office of Space Science.
Comparison of collimation systems for small-angle neutron scattering
Seeger, P.A.
1985-01-01T23:59:59.000Z
It is shown by simple first-order geometric arguments that for a given resolution, the flux on sample in a small-angle scattering instrument is independent of the form of the collimator or of the length of the instrument. Count rate may be increased by increasing the sample size, through the use of multi-aperture systems. In second order, it is shown to be advantageous to place the beam defining elements as close as possible to the source and the sample. The multiple-pinhole system gives maximum flux on small samples but has non-uniform illumination so that intensity increases only about half as fast as sample area. Soller slits and continuous tubes from source to sample were also considered, but neutron scattering and reflection from surfaces generate a large halo. Monte-Carlo simulations confirm these results, with the conclusion that the optimum collimator configuration is the multiple-pinhole system. 4 refs., 4 figs.
Noncollinear ferromagnetic easy axes in Py/Ru/FeCo/IrMn spin valves induced by oblique deposition
Bueno, T. E. P.; Parreiras, D. E.; Gomes, G. F. M.; Krambrock, K.; Paniago, R. [Departamento de Física, ICEx, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG (Brazil); Michea, S.; Rodríguez-Suárez, R. L. [Centro de Investigación en Nanotecnología y Materiales Avanzados “CIEN-UC,” Pontifícia Universidad Católica de Chile, Casilla 306, Santiago (Chile); Filho, M. S. Araújo; Macedo, W. A. A. [Laboratório de Física Aplicada, Centro de Desenvolvimento da Tecnologia Nuclear, 30123-970 Belo Horizonte, MG (Brazil)
2014-06-16T23:59:59.000Z
We present an investigation on the magnetic properties of Py/Ru/FeCo/IrMn spin valves grown by dc magnetron sputtering. The sample fabrication setup has two important features, (i) the five magnetron sputtering sources are placed in a cluster flange 72° from each other, and (ii) each source is tilted with respect to the sample normal. In-plane angular dependence of the ferromagnetic resonance (FMR) was used to obtain the relevant magnetic anisotropies, such as uniaxial and exchange bias fields. The oblique deposition geometry employed has induced non-collinear easy axes of the two ferromagnetic (FM) layers, with high uniaxial field strengths. The symmetry shift of the angular dependence of the FMR resonances of the two FM layers gives us directly the angle between the easy axes of FM{sub 1} (Py) and FM{sub 2} (FeCo), which turned out to be the angle between two adjacent sputtering sources. The observations of the present study suggest that, by combining oblique deposition and appropriate angles of incidence of the deposition flux, the uniaxial (and unidirectional) axes of individual FM layers can be precisely engineered in spin valve fabrication.
ANALYSIS OF SPIN-ORBIT ALIGNMENT IN THE WASP-32, WASP-38, AND HAT-P-27/WASP-40 SYSTEMS
Brown, D. J. A.; Collier Cameron, A.; Enoch, B.; Miller, G. R. M. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Diaz, R. F. [LAM (Laboratoire d'Astrophysique de Marseille), Aix Marseille Universite, CNRS, UMR 7326, F-13388 Marseille (France); Doyle, A. P.; Smalley, B.; Anderson, D. R.; Hellier, C.; Maxted, P. F. L. [Astrophysics Group, School of Physical and Geographical Sciences, Lennard-Jones Building, Keele University, Staffordshire ST5 5BG (United Kingdom); Gillon, M. [Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout, 17 (Bat. B5C) Sart Tilman, B-4000 Liege (Belgium); Lendl, M.; Triaud, A. H. M. J.; Queloz, D. [Observatoire Astronomique de l'Universite de Geneve, 51 Chemin des Maillettes, CH-1290 Sauverny (Switzerland); Pollacco, D. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, University Road, Belfast BT7 1NN (United Kingdom); Boisse, I. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Hebrard, G., E-mail: djab@st-andrews.ac.uk [Institut dAstrophysique de Paris, UMR7095 CNRS, Universite Pierre and Marie Curie, 98bis boulevard Arago, F-75014 Paris (France)
2012-12-01T23:59:59.000Z
We present measurements of the spin-orbit alignment angle, {lambda}, for the hot Jupiter systems WASP-32, WASP-38, and HAT-P-27/WASP-40, based on data obtained using the HARPS spectrograph. We analyze the Rossiter-McLaughlin effect for all three systems and also carry out Doppler tomography for WASP-32 and WASP-38. We find that WASP-32 (T {sub eff} = 6140{sup +90} {sub -100} K) is aligned, with an alignment angle of {lambda} = 10.{sup 0}5{sup +6.4} {sub -6.5} obtained through tomography, and that WASP-38 (T {sub eff} = 6180{sup +40} {sub -60} K) is also aligned, with tomographic analysis yielding {lambda} = 7.{sup 0}5{sup +4.7} {sub -6.1}. The latter result provides an order-of-magnitude improvement in the uncertainty in {lambda} compared to the previous analysis of Simpson et al. We are only able to loosely constrain the angle for HAT-P-27/WASP-40 (T{sub eff} = 5190{sup +160} {sub -170} K) to {lambda} = 24.{sup 0}2{sup +76.0}{sub -44.5}, owing to the poor signal-to-noise ratio of our data. We consider this result a non-detection under a slightly updated version of the alignment test of Brown et al. We place our results in the context of the full sample of spin-orbit alignment measurements, finding that they provide further support for previously established trends.
On conformal higher spin wave operators
Teake Nutma; Massimo Taronna
2014-07-08T23:59:59.000Z
We analyze free conformal higher spin actions and the corresponding wave operators in arbitrary even dimensions and backgrounds. We show that the wave operators do not factorize in general, and identify the Weyl tensor and its derivatives as the obstruction to factorization. We give a manifestly factorized form for them on (A)dS backgrounds for arbitrary spin and on Einstein backgrounds for spin 2. We are also able to fix the conformal wave operator in d=4 for s=3 up to linear order in the Riemann tensor on generic Bach-flat backgrounds.
Simulating spin-charge separation with light
Dimitris G. Angelakis; Mingxia Huo; Elica Kyoseva; Leong Chuan kwek
2010-06-08T23:59:59.000Z
In this work we show that stationary light-matter excitations generated inside a hollow one-dimensional waveguide filled with atoms, can be made to generate a photonic two-component Lieb Liniger model. We explain how to prepare and drive the atomic system to a strongly interacting regime where spin-charge separation could be possible. We then proceed by explaining how to measure the corresponding effective spin and charge densities and velocities through standard optical methods based in measuring dynamically the emitted photon intensities or by analyzing the photon spectrum. The relevant interactions exhibit the necessary tunability both to generate and efficiently observe spin charge separation with current technology.
Dynamic control of spin wave spectra using spin-polarized currents
Wang, Qi; Zhang, Huaiwu, E-mail: hwzhang@uestc.edu.cn; Tang, Xiaoli; Bai, Feiming; Zhong, Zhiyong, E-mail: zzy@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Fangohr, Hans [Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)
2014-09-15T23:59:59.000Z
We describe a method of controlling the spin wave spectra dynamically in a uniform nanostripe waveguide through spin-polarized currents. A stable periodic magnetization structure is observed when the current flows vertically through the center of nanostripe waveguide. After being excited, the spin wave is transmitted at the sides of the waveguide. Numerical simulations of spin-wave transmission and dispersion curves reveal a single, pronounced band gap. Moreover, the periodic magnetization structure can be turned on and off by the spin-polarized current. The switching process from full rejection to full transmission takes place within less than 3?ns. Thus, this type magnonic waveguide can be utilized for low-dissipation spin wave based filters.
Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); Grimaldi, E., E-mail: eva.grimaldi@thalesgroup.com [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); CNES, 1 Avenue Edouard Belin, 31400 Toulouse (France); Khvalkovskiy, A. V. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); A.M. Prokhorov General Physics Institute of RAS, Vavilova Str. 38, 119991 Moscow (Russian Federation); Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
2014-07-14T23:59:59.000Z
We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6??W) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bhatti, Kanwal Preet; El-Khatib, S.; Srivastava, Vijay; James, R. D.; Leighton, C.
2012-04-01T23:59:59.000Z
The Heusler-derived multiferroic alloy Ni50–xCoxMn??Sn?? has recently been shown to exhibit, at just above room temperature, a highly reversible martensitic phase transformation with an unusually large magnetization change. In this work the nature of the magnetic ordering above and below this transformation has been studied in detail in the critical composition range x = 6–8 via temperature-dependent (5–600 K) magnetometry and small-angle neutron scattering (SANS). We observe fairly typical paramagnetic to long-range-ordered ferromagnetic phase transitions on cooling to 420–430 K, with the expected critical spin fluctuations, followed by first-order martensitic phase transformations to a nonferromagnetic state below 360–390 K. Themore »static magnetization reveals complex magnetism in this low-temperature nonferromagnetic phase, including a Langevin-like field dependence, distinct spin freezing near 60 K, and significant exchange bias effects, consistent with superparamagnetic blocking of ferromagnetic clusters of nanoscopic dimensions. We demonstrate that these spin clusters, whose existence has been hypothesized in a variety of martensitic alloys exhibiting competition between ferromagnetic and antiferromagnetic exchange interactions, can be directly observed by SANS. The scattering data are consistent with a liquidlike spatial distribution of interacting magnetic clusters with a mean center-to-center spacing of 12 nm. Considering the behavior of the superparmagnetism, cooling-field and temperature-dependent exchange bias, and magnetic SANS, we discuss in detail the physical form and origin of these spin clusters, their intercluster interactions, the nature of the ground-state magnetic ordering in the martensitic phase, and the implications for our understanding of such alloy systems.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bhatti, Kanwal Preet; El-Khatib, S.; Srivastava, Vijay; James, R. D.; Leighton, C.
2012-04-01T23:59:59.000Z
The Heusler-derived multiferroic alloy Ni50–xCoxMn??Sn?? has recently been shown to exhibit, at just above room temperature, a highly reversible martensitic phase transformation with an unusually large magnetization change. In this work the nature of the magnetic ordering above and below this transformation has been studied in detail in the critical composition range x = 6–8 via temperature-dependent (5–600 K) magnetometry and small-angle neutron scattering (SANS). We observe fairly typical paramagnetic to long-range-ordered ferromagnetic phase transitions on cooling to 420–430 K, with the expected critical spin fluctuations, followed by first-order martensitic phase transformations to a nonferromagnetic state below 360–390 K. The static magnetization reveals complex magnetism in this low-temperature nonferromagnetic phase, including a Langevin-like field dependence, distinct spin freezing near 60 K, and significant exchange bias effects, consistent with superparamagnetic blocking of ferromagnetic clusters of nanoscopic dimensions. We demonstrate that these spin clusters, whose existence has been hypothesized in a variety of martensitic alloys exhibiting competition between ferromagnetic and antiferromagnetic exchange interactions, can be directly observed by SANS. The scattering data are consistent with a liquidlike spatial distribution of interacting magnetic clusters with a mean center-to-center spacing of 12 nm. Considering the behavior of the superparmagnetism, cooling-field and temperature-dependent exchange bias, and magnetic SANS, we discuss in detail the physical form and origin of these spin clusters, their intercluster interactions, the nature of the ground-state magnetic ordering in the martensitic phase, and the implications for our understanding of such alloy systems.
Germanium Nanowire Spin-Valve Device (DMR-0819860)
Petta, Jason
Germanium Nanowire Spin-Valve Device (DMR-0819860) E-S Liu, J. Nah, K.Varahramyan, and E. Tutuc (Univ. of Texas at Austin) Figure 1 The spin-valve device comprised of a Ge nanowire bracketed by two in direction, the spin current is suppressed (spin-valve action). An applied magnetic field By is used
Spin drift in highly doped n-type Si
Kameno, Makoto; Ando, Yuichiro; Shinjo, Teruya [Graduate School of Engineering Science, Osaka University Osaka (Japan); Koike, Hayato; Sasaki, Tomoyuki; Oikawa, Tohru [Advanced Technology Development Center, TDK Cooperation, Chiba (Japan); Suzuki, Toshio [AIT, Akita Research Institute of Advanced Technology, Akita (Japan); Shiraishi, Masashi, E-mail: mshiraishi@kuee.kyoto-u.ac.jp [Graduate School of Engineering Science, Osaka University Osaka (Japan); Graduate School of Engineering, Kyoto University, Kyoto (Japan)
2014-03-03T23:59:59.000Z
A quantitative estimation of spin drift velocity in highly doped n-type silicon (Si) at 8?K is presented in this letter. A local two-terminal Hanle measurement enables the detection of a modulation of spin signals from the Si as a function of an external electric field, and this modulation is analyzed by using a spin drift-diffusion equation and an analytical solution of the Hanle-type spin precession. The analyses reveal that the spin drift velocity is linearly proportional to the electric field. The contribution of the spin drift effect to the spin signals is crosschecked by introducing a modified nonlocal four-terminal method.
Surface spin flip probability of mesoscopic Ag wires.
Mihajlovic, G.; Pearson, J. E.; Bader, S. D.; Hoffmann, A.
2010-06-08T23:59:59.000Z
Spin relaxation in mesoscopic Ag wires in the diffusive transport regime is studied via nonlocal spin valve and Hanle effect measurements performed on Permalloy/Ag lateral spin valves. The ratio between momentum and spin relaxation times is not constant at low temperatures. This can be explained with the Elliott-Yafet spin relaxation mechanism by considering the momentum surface relaxation time as being temperature dependent. We present a model to separately determine spin flip probabilities for phonon, impurity and surface scattering and find that the spin flip probability is highest for surface scattering.
K. -S. Park; H. Han
2011-05-31T23:59:59.000Z
Making use of index theorem and spin Chern Simons theory, we construct an effective topological field theory of strongly correlated topological insulators coupling to a nonabelian gauge field $ SU(N) $ with an interaction constant $ g $ in the absence of the time-reversal symmetry breaking. If $ N $ and $ g $ allow us to define a t'Hooft parameter $ \\lambda $ of effective coupling as $ \\lambda = N g^{2} $, then our construction leads to the fractional quantum Hall effect on the surface with Hall conductance $ \\sigma_{H}^{s} = \\frac{1}{4\\lambda} \\frac{e^{2}}{h} $. For the magnetoelectric response described by a bulk axion angle $ \\theta $, we propose that the fractional magnetoelectric effect can be realized in gapped time reversal invariant topological insulators of strongly correlated bosons or fermions with an effective axion angle $ \\theta_{eff} = \\frac{\\pi}{2 \\lambda} $ if they can have fractional excitations and degenerate ground states on topologically nontrivial and oriented spaces. Provided that an effective charge is given by $ e_{eff} = \\frac{e}{\\sqrt{2 \\lambda}} $, it is shown that $ \\sigma_{H}^{s} = \\frac{e_{eff}^{2}}{2h} $, resulting in a surface Hall conductance of gapless fermions with $ e_{eff} $ and a pure axion angle $ \\theta = \\pi $.
Effect of cosmic string on spin dynamics
Debashree Chowdhury; B. Basu
2014-11-07T23:59:59.000Z
In the present paper, we have investigated the role of cosmic string on spin current and Hall electric field. Due to the background cosmic string, the modified electric field of the system generates renormalized spin orbit coupling, which induces a modified non-Abelian gauge field. The defect causes a change in the AB and AC phases appearing due to the modified electromagnetic field. In addition, for a time varying electric field we perform explicit analytic calculations to derive the exact form of spin electric field and spin current, which is defect parameter dependent and of oscillating type. Furthermore, in an asymmetric crystal within the Drude model approach we investigate the dependence of the cosmic string parameters on cosmic string induced Hall electric field.
Spin injection and manipulation in organic semiconductors
Venkataraman, Karthik (Karthik Raman)
2011-01-01T23:59:59.000Z
The use of organic semiconductors to enable organic spintronic devices requires the understanding of transport and control of the spin state of the carriers. This thesis deals with the above issue, focusing on the interface ...
Spinning branes in Riemann-Cartan spacetime
Vasilic, Milovan; Vojinovic, Marko [Institute of Physics, P.O. Box 57, 11001 Belgrade (Serbia)
2008-11-15T23:59:59.000Z
We use the conservation law of the stress-energy and spin tensors to study the motion of massive branelike objects in Riemann-Cartan geometry. The world-sheet equations and boundary conditions are obtained in a manifestly covariant form. In the particle case, the resultant worldline equations turn out to exhibit a novel spin-curvature coupling. In particular, the spin of a zero-size particle does not couple to the background curvature. In the string case, the world-sheet dynamics is studied for some special choices of spin and torsion. As a result, the known coupling to the Kalb-Ramond antisymmetric external field is obtained. Geometrically, the Kalb-Ramond field has been recognized as a part of the torsion itself, rather than the torsion potential.
Bachelor Thesis Joule Heating Induced Spin Seebeck
Gross, Rudolf
by Uchida et al. [1]. The SSE enables the generation of a pure spin current by applying a thermal gradient Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Computation of the thermal . . . . . . . . . . . . . . . . . . . . . . . . 13 4.2 Electric Effects and Data Reduction . . . . . . . . . . . . . . . . . . . . . . 15 5
Intrinsic Spin-Orbit Interaction in Graphene
B. S. Kandemir
2012-05-03T23:59:59.000Z
In graphene, we report the first theoretical demonstration of how the intrinsic spin orbit interaction can be deduced from the theory and how it can be controlled by tuning a uniform magnetic field, and/or by changing the strength of a long range Coulomb like impurity (adatom), as well as gap parameter. In the impurity context, we find that intrinsic spin-orbit interaction energy may be enhanced by increasing the strength of magnetic field and/or by decreasing the band gap mass term. Additionally, it may be strongly enhanced by increasing the impurity strength. Furthermore, from the proposal of Kane and Mele [Phys. Rev. Lett. 95, 226801 (2005)], it was discussed that the pristine graphene has a quantized spin Hall effect regime where the Rashba type spin orbit interaction term is smaller than that of intrinsic one. Our analysis suggest the nonexistence of such a regime in the ground state of flat graphene.
Spin effects in single-electron transistors
Granger, Ghislain
2005-01-01T23:59:59.000Z
Basic electron transport phenomena observed in single-electron transistors (SETs) are introduced, such as Coulomb-blockade diamonds, inelastic cotunneling thresholds, the spin-1/2 Kondo effect, and Fano interference. With ...
Resolution of the Proton Spin Problem
F. Myhrer; A. W. Thomas
2007-09-24T23:59:59.000Z
A number of lines of investigation into the structure of the nucleon have converged to the point where we believe that one has a consistent explanation of the well known proton spin crisis.
Environment-assisted metrology with spin qubits
Cappellaro, Paola
We investigate the sensitivity of a recently proposed method for precision measurement [ Phys. Rev. Lett. 106 140502 (2011)], focusing on an implementation based on solid-state spin systems. The scheme amplifies a quantum ...
Noncommutative geometry induced by spin effects
Colatto, L.P.; Penna, A.L.A.; Santos, W.C. [Departamento de Fisica, Centro de Ciencias Exatas, Universidade Federal do Espirito Santo, Avenue Fernando Ferrari, 514, CEP 29075-910, Vitoria, ES (Brazil); Instituto de Fisica, Universidade de Brasilia, CEP 70919-970, Brasilia, DF (Brazil)
2006-05-15T23:59:59.000Z
In this paper we study the nonlocal effects of noncommutative spacetime on simple physical systems. Our main point is the assumption that the noncommutative effects are consequences of a background field which generates a local spin structure. So, we reformulate some simple electrostatic models in the presence of a spin-deformation contribution to the geometry of the motion, and we obtain an interesting correlation amongst the deformed area vector, the 3D noncommutative effects, and the usual spin vector S-vector given in quantum mechanics framework. Remarkably we can observe that a spin-orbit coupling term comes to light on the spatial sector of a potential written in terms of noncommutative coordinates which indicates that bound states are particular cases in this procedure. Concerning confined or bounded particles in this noncommutative domain, we verify that the kinetic energy is modified by a deformation factor. Finally, we discuss perspectives.
Spin dynamics simulation of electron spin relaxation in Ni{sup 2+}(aq)
Rantaharju, Jyrki, E-mail: jjrantaharju@gmail.com; Mareš, Ji?í, E-mail: jiri.mares@oulu.fi; Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, Oulu, FIN-90014 (Finland)
2014-07-07T23:59:59.000Z
The ability to quantitatively predict and analyze the rate of electron spin relaxation of open-shell systems is important for electron paramagnetic resonance and paramagnetic nuclear magnetic resonance spectroscopies. We present a combined molecular dynamics (MD), quantum chemistry (QC), and spin dynamics simulation method for calculating such spin relaxation rates. The method is based on the sampling of a MD trajectory by QC calculations, to produce instantaneous parameters of the spin Hamiltonian used, in turn, to numerically solve the Liouville-von Neumann equation for the time evolution of the spin density matrix. We demonstrate the approach by simulating the relaxation of electron spin in an aqueous solution of Ni{sup 2+} ion. The spin-lattice (T{sub 1}) and spin-spin (T{sub 2}) relaxation rates are extracted directly from the simulations of the time dependence of the longitudinal and transverse magnetization, respectively. Good agreement with the available, indirectly obtained experimental data is obtained by our method.
Nonvanishing spin Hall currents in disordered spin-orbit coupling systems
Nomura, K.; Sinova, Jairo; Jungwirth, T.; Niu, Q.; MacDonald, A. H.
2005-01-01T23:59:59.000Z
. 2, are consistent with expectations for this thoroughly studied quantity.35 Our main interest at present, however, is the system size dependence of the spin Hall conductivity ssH and particularly in establish- ing whether or not it vanishes... quasiparticle velocity and the z compo- nent of spin induced by an electric field; for an electric field in the x direction, an up spin is induced in positive y-component velocity majority-band states and a correspond- ing down spin at negative velocities...
Spin transistor operation driven by the Rashba spin-orbit coupling in the gated nanowire
Wójcik, P.; Adamowski, J., E-mail: adamowski@fis.agh.edu.pl; Spisak, B. J.; Wo?oszyn, M. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, Kraków (Poland)
2014-03-14T23:59:59.000Z
A theoretical description has been proposed for the operation of the spin transistor in the gate-controlled InAs nanowire. The calculated current-voltage characteristics show that the electron current flowing from the source (spin injector) to the drain (spin detector) oscillates as a function of the gate voltage, which results from the precession of the electron spin caused by the Rashba spin-orbit interaction in the vicinity of the gate. We have studied the operation of the spin transistor under the following conditions: (A) the full spin polarization of electrons in the contacts, zero temperature, and the single conduction channel corresponding to the lowest-energy subband of the transverse motion and (B) the partial spin polarization of the electrons in the contacts, the room temperature, and the conduction via many transverse subbands taken into account. For case (A), the spin-polarized current can be switched on/off by the suitable tuning of the gate voltage, for case (B) the current also exhibits the pronounced oscillations but with no-zero minimal values. The computational results obtained for case (B) have been compared with the recent experimental data and a good agreement has been found.
High-Spin Cobalt Hydrides for Catalysis
Holland, Patrick L. [Yale University] [Yale University
2013-08-29T23:59:59.000Z
Organometallic chemists have traditionally used catalysts with strong-field ligands that give low-spin complexes. However, complexes with a weak ligand field have weaker bonds and lower barriers to geometric changes, suggesting that they may lead to more rapid catalytic reactions. Developing our understanding of high-spin complexes requires the use of a broader range of spectroscopic techniques, but has the promise of changing the mechanism and/or selectivity of known catalytic reactions. These changes may enable the more efficient utilization of chemical resources. A special advantage of cobalt and iron catalysts is that the metals are more abundant and cheaper than those currently used for major industrial processes that convert unsaturated organic molecules and biofeedstocks into useful chemicals. This project specifically evaluated the potential of high-spin cobalt complexes for small-molecule reactions for bond rearrangement and cleavage reactions relevant to hydrocarbon transformations. We have learned that many of these reactions proceed through crossing to different spin states: for example, high-spin complexes can flip one electron spin to access a lower-energy reaction pathway for beta-hydride elimination. This reaction enables new, selective olefin isomerization catalysis. The high-spin cobalt complexes also cleave the C-O bond of CO2 and the C-F bonds of fluoroarenes. In each case, the detailed mechanism of the reaction has been determined. Importantly, we have discovered that the cobalt catalysts described here give distinctive selectivities that are better than known catalysts. These selectivities come from a synergy between supporting ligand design and electronic control of the spin-state crossing in the reactions.
A New Spin on Neutrino Quantum Kinetics
Vincenzo Cirigliano; George M. Fuller; Alexey Vlasenko
2014-06-20T23:59:59.000Z
We present and discuss the quantum kinetic equations (QKEs) which govern neutrino flavor and spin evolution in hot, dense, and anisotropic media. A novel feature of these QKEs is the presence of a coherent spin-flip term which can mediate neutrino-antineutrino transformation for Majorana neutrinos and active-sterile transformation for Dirac neutrinos. We provide an alternative derivation of this term based on a standard effective Hamiltonian.
Geometric Spin Hall Effect of Light
Andrea Aiello; Christoph Marquardt; Gerd Leuchs
2009-02-26T23:59:59.000Z
We describe a novel phenomenon occurring when a polarized Gaussian beam of light is observed in a Cartesian reference frame whose axes are not parallel to the direction of propagation of the beam. Such phenomenon amounts to an intriguing spin-dependent shift of the position of the center of the beam, with manners akin to the spin Hall effect of light. We demonstrate that this effect is unavoidable when the light beam possesses a nonzero transverse angular momentum.
Thermal entanglement properties of small spin clusters
Bose, Indrani; Tribedi, Amit [Department of Physics, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata 700 009 (India)
2005-08-15T23:59:59.000Z
Exchange interactions in spin systems can give rise to quantum entanglement in the ground and thermal states of the systems. We consider a spin tetramer, with spins of magnitude (1/2), in which the spins interact via nearest-neighbor, diagonal, and four-spin interactions of strength J{sub 1}, J{sub 2}, and K, respectively. The ground- and thermal-state entanglement properties of the tetramer are calculated analytically in the various limiting cases. Both bipartite and multipartite entanglements are considered and a signature of the quantum phase transition (QPT), in terms of the entanglement ratio, is identified. The first-order QPT is accompanied by discontinuities in the nearest-neighbor and diagonal concurrences. The magnetic properties of a S=(1/2) antiferromagnetic polyoxovanadate compound V12 are well explained by tetramers, with J{sub 2}=0, K=0, in which the spins interact via the isotropic Heisenberg exchange interaction Hamiltonian. Treating the magnetic susceptibility {chi} as an entanglement witness (EW), an estimate of the lower bound of the critical entanglement temperature T{sub c} below which entanglement is present in the experimental compound, is determined. Two other cases considered include the symmetric tetramer--i.e., tetrahedron (J{sub 1}=J{sub 2},K=0)--and the symmetric trimer. In both the cases, there is no entanglement between a pair of spins in the thermal state but multipartite entanglement is present. A second EW based on energy provides an estimate of the entanglement temperature T{sub E} below which the thermal state is definitely entangled. This EW detects bipartite entanglement in the case of the tetramer describing a square of spins (the case of V12 ) and multipartite entanglement in the cases of the tetrahedron and symmetric trimer.
Mossbauer and Integer-Spin EPR Studies and Spin-Coupling Analysis of the [4Fe-4S]0
Hendrich, Mike
Mo¨ssbauer and Integer-Spin EPR Studies and Spin-Coupling Analysis of the [4Fe-4S]0 Cluster here this state with integer-spin EPR and Mo¨ssbauer spectroscopy, and analyzed the exchange couplings from four high-spin ferrous sites must have this property. From Mo¨ssbauer spectroscopy we obtained
Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a,
Rosen, Matthew S
Dependence of nuclear spin singlet lifetimes on RF spin-locking power Stephen J. DeVience a: Received 6 January 2012 Revised 14 March 2012 Available online 28 March 2012 Keywords: Nuclear singlet of long-lived nuclear spin singlet states as a function of the strength of the RF spin-locking field
Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)
2013-07-01T23:59:59.000Z
The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.
Quantum corrections to spin effects in general relativity
G. G. Kirilin
2005-07-16T23:59:59.000Z
Quantum power corrections to the gravitational spin-orbit and spin-spin interactions, as well as to the Lense-Thirring effect, were found for particles of spin 1/2. These corrections arise from diagrams of second order in Newton gravitational constant G with two massless particles in the unitary cut in the t-channel. The corrections obtained differ from the previous calculation of the corrections to spin effects for rotating compound bodies with spinless constituents.
Kumano, S
2015-01-01T23:59:59.000Z
Spin-physics projects at J-PARC are explained by including future possibilities. J-PARC is the most-intense hadron-beam facility in the high-energy region above multi-GeV, and spin physics will be investigated by using secondary beams of kaons, pions, neutrinos, muons, and antiproton as well as the primary-beam proton. In particle physics, spin topics are on muon $g-2$, muon and neutron electric dipole moments, and time-reversal violation experiment in a kaon decay. Here, we focus more on hadron-spin physics as for future projects. For example, generalized parton distributions (GPDs) could be investigated by using pion and proton beams, whereas they are studied by the virtual Compton scattering at lepton facilities. The GPDs are key quantities for determining the three-dimensional picture of hadrons and for finding the origin of the nucleon spin including partonic orbital-angular-momentum contributions. In addition, polarized parton distributions and various hadron spin topics should be possible by using the ...
Motional Spin Relaxation in Large Electric Fields
Schmid, Riccardo; Filippone, B W
2008-01-01T23:59:59.000Z
We discuss the precession of spin-polarized Ultra Cold Neutrons (UCN) and $^{3}\\mathrm{He}$ atoms in uniform and static magnetic and electric fields and calculate the spin relaxation effects from motional $v\\times E$ magnetic fields. Particle motion in an electric field creates a motional $v\\times E$ magnetic field, which when combined with collisions, produces variations of the total magnetic field and results in spin relaxation of neutron and $^{3}\\mathrm{He}$ samples. The spin relaxation times $T_{1}$ (longitudinal) and $T_{2}$ (transverse) of spin-polarized UCN and $^{3}\\mathrm{He}$ atoms are important considerations in a new search for the neutron Electric Dipole Moment at the SNS \\emph{nEDM} experiment. We use a Monte Carlo approach to simulate the relaxation of spins due to the motional $v\\times E$ field for UCN and for $^{3}\\mathrm{He}$ atoms at temperatures below $600 \\mathrm{mK}$. We find the relaxation times for the neutron due to the $v\\times E$ effect to be long compared to the neutron lifetime, ...
Motional Spin Relaxation in Large Electric Fields
Riccardo Schmid; B. Plaster; B. W. Filippone
2008-07-02T23:59:59.000Z
We discuss the precession of spin-polarized Ultra Cold Neutrons (UCN) and $^{3}$He atoms in uniform and static magnetic and electric fields and calculate the spin relaxation effects from motional $v\\times E$ magnetic fields. Particle motion in an electric field creates a motional $v\\times E$ magnetic field, which when combined with collisions, produces variations of the total magnetic field and results in spin relaxation of neutron and $^{3}$He samples. The spin relaxation times $T_{1}$ (longitudinal) and $T_{2}$ (transverse) of spin-polarized UCN and $^{3}$He atoms are important considerations in a new search for the neutron Electric Dipole Moment at the SNS \\emph{nEDM} experiment. We use a Monte Carlo approach to simulate the relaxation of spins due to the motional $v\\times E$ field for UCN and for $^{3}$He atoms at temperatures below $600,\\mathrm{mK}$. We find the relaxation times for the neutron due to the $v\\times E$ effect to be long compared to the neutron lifetime, while the $^{3}$He relaxation times may be important for the \\emph{nEDM} experiment.
Spin structure in high energy processes: Proceedings
DePorcel, L.; Dunwoodie, C. [eds.
1994-12-01T23:59:59.000Z
This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.
Charged spinning black holes as particle accelerators
Wei Shaowen; Liu Yuxiao; Guo Heng; Fu Chune [Institute of Theoretical Physics, Lanzhou University, Lanzhou 730000 (China)
2010-11-15T23:59:59.000Z
It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin a but also on the charge Q of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin a of the extremal black hole satisfies (1/{radical}(3)){<=}(a/M){<=}1, where M is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge Q.
Information storage capacity of discrete spin systems
Yoshida, Beni, E-mail: rouge@caltech.edu
2013-11-15T23:59:59.000Z
Understanding the limits imposed on information storage capacity of physical systems is a problem of fundamental and practical importance which bridges physics and information science. There is a well-known upper bound on the amount of information that can be stored reliably in a given volume of discrete spin systems which are supported by gapped local Hamiltonians. However, all the previously known systems were far below this theoretical bound, and it remained open whether there exists a gapped spin system that saturates this bound. Here, we present a construction of spin systems which saturate this theoretical limit asymptotically by borrowing an idea from fractal properties arising in the Sierpinski triangle. Our construction provides not only the best classical error-correcting code which is physically realizable as the energy ground space of gapped frustration-free Hamiltonians, but also a new research avenue for correlated spin phases with fractal spin configurations. -- Highlights: •We propose a spin model with fractal ground states and study its coding properties. •We show that the model asymptotically saturates a theoretical limit on information storage capacity. •We discuss its relations to various theoretical physics problems.
Simulation of multilevel cell spin transfer switching in a full-Heusler alloy spin-valve nanopillar
Chen, Long-Qing
Simulation of multilevel cell spin transfer switching in a full-Heusler alloy spin-valve nanopillar of multilevel cell spin transfer switching in a full-Heusler alloy spin-valve nanopillar H. B. Huang,1,2 X. Q in a full-Heusler Co2FeAl0.5Si0.5 alloy spin-valve nanopillar was investigated using micromagnetic
Method and apparatus for controlling pitch and flap angles of a wind turbine
Deering, Kenneth J. (Seattle, WA); Wohlwend, Keith P. (Issaquah, WA)
2009-05-12T23:59:59.000Z
A wind turbine with improved response to wind conditions is provided. Blade flap angle motion is accompanied by a change in pitch angle by an amount defining a pitch/flap coupling ratio. The coupling ratio is non-constant as a function of a flap angle and is preferably a substantially continuous, non-linear function of flap angle. The non-constant coupling ratio can be provided by mechanical systems such as a series of linkages or by configuring electronic or other control systems and/or angle sensors. A link with a movable proximal end advantageously is part of the mechanical system. The system can provide relatively large coupling ratios and relatively large rates of coupling ratio changes especially for near-feather pitches and low flap angles.
Development of a hybrid margin angle controller for HVDC continuous operation
Sato, M. [Kansai Electric Power Co., Osaka (Japan)] [Kansai Electric Power Co., Osaka (Japan); Yamaji, K. [Shikoku Electric Power Co., Takamatsu (Japan)] [Shikoku Electric Power Co., Takamatsu (Japan); Sekita, M. [Electric Power Development Co., Tokyo (Japan)] [Electric Power Development Co., Tokyo (Japan); Amano, M.; Nishimura, M.; Konishi, H.; Oomori, T. [Hitachi, Ltd. (Japan)] [Hitachi, Ltd. (Japan)
1996-11-01T23:59:59.000Z
The objective of this paper is to present a new hybrid margin angle control method for HVDC continuous operation under AC system fault conditions. For stable continuous operation of HVDC systems, the margin angle controller must be designed to maintain the necessary margin angle to avoid commutation failures. The proposed method uses the open loop margin angle controller (MAC) as the basic controller, and adds output from the closed loop MAC to correct the control angle. A fast voltage detection algorithm is used for open loop control, and margin angle reference correction using harmonics detection for closed loop control are also developed. The combination of open and closed loop control provides quick responses when faults occur with stable and speedy recovery after fault clearance. The effectiveness of the developed controller is confirmed through EMTP digital simulations and also with the experiments using an analogue simulator.
Ultrasonic estimation of the contact angle of a sessile droplet
Quintero, R.; Simonetti, F. [Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH 45221 (United States)
2014-02-18T23:59:59.000Z
Radiation of energy by large amplitude leaky Rayleigh waves is regarded as one of the key physical mechanisms regulating the actuation and manipulation of droplets in surface acoustic wave (SAW) microfluidic devices. The interaction between a SAW and a droplet is highly complex and is presently the subject of extensive research. This paper investigates the existence of an additional interaction mechanism based on the propagation of quasi-Stoneley waves inside sessile droplets deposited on a solid substrate. In contrast with the leaky Rayleigh wave, the energy of the Stoneley wave is confined within a thin fluid layer in contact with the substrate. The hypothesis is confirmed by three-dimensional finite element simulations and ultrasonic scattering experiments measuring the reflection of Rayleigh waves from droplets of different diameters. Moreover, real-time monitoring of the droplet evaporation process reveals a clear correlation between the droplet contact angle and the spectral information of the reflected Rayleigh signal, thus paving the way for ultrasonic measurements of surface tension.
The XMM-Newton Wide Angle Survey (XWAS)
Esquej, P; Carrera, F J; Mateos, S; Tedds, J; Watson, M G; Corral, A; Ebrero, J; Krumpe, M; Rosen, S R; Ceballos, M T; Schwope, A; Page, C; Alonso-Herrero, A; Caccianiga, A; Della Ceca, R; Gonzalez-Martín, O; Lamer, G; Severgnini, P
2013-01-01T23:59:59.000Z
This programme is aimed at obtaining one of the largest X-ray selected samples of identified active galactic nuclei to date in order to characterise such a population at intermediate fluxes, where most of the Universe's accretion power originates. We present the XMM-Newton Wide Angle Survey (XWAS), a new catalogue of almost a thousand X-ray sources spectroscopically identified through optical observations. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fibre spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R~21, with preference for X-ray sources having a flux F(0.5-4.5 keV) >10^-14 erg s^-1 cm^-2. Optical spectroscopic observations performed at the Anglo Australian Telescope Two Degree Field were analysed, and the derived spectra were classified based on optical emission lines. We have identified ...
Measurements of the CKM Angle Alpha at BaBar
Stracka, Simone; /Milan U. /INFN, Milan; ,
2012-04-04T23:59:59.000Z
The authors present improved measurements of the branching fractions and CP-asymmetries fin the B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and B{sup +} {yields} {rho}{sup +}{rho}{sup 0} decays, which impact the determination of {alpha}. The combined branching fractions of B {yields} K{sub 1}(1270){pi} and B {yields} K{sub 1}(1400){pi} decays are measured for the first time and allow a novel determination of {alpha} in the B{sup 0} {yields} {alpha}{sub 1}(1260){sup {+-}}{pi}{sup {-+}} decay channel. These measurements are performed using the final dataset collected by the BaBar detector at the PEP-II B-factory. The primary goal of the experiments based at the B factories is to test the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP violation in the standard model of electroweak interactions. This can be achieved by measuring the angles and sides of the Unitarity Triangle in a redundant way.
Angle stations in or for endless conveyor belts
Steel, Alan (Glasgow, GB6)
1987-04-07T23:59:59.000Z
In an angle station for an endless conveyor belt, there are presented to each incoming run of the belt stationary curved guide members (18, 19) of the shape of a major segment of a right-circular cylinder and having in the part-cylindrical portion (16 or 17) thereof rectangular openings (15) arranged in parallel and helical paths and through which project small freely-rotatable rollers (14), the continuously-changing segments of the curved surfaces of which projecting through said openings (15) are in attitude to change the direction of travel of the belt (13) through 90.degree. during passage of the belt about the part-cylindrical portion (16 or 17) of the guide member (18 or 19). The rectangular openings (15) are arranged with their longer edges lengthwise of the diagonals representing the mean of the helix but with those of a plurality of the rows nearest to each end of the part-cylindrical portion (16 or 17) slightly out of axial symmetry with said diagonals, being slightly inclined in a direction about the intersections (40) of the diagonals of the main portion of the openings, to provide a "toe-in" attitude in relation to the line of run of the endless conveyor belt.
Small angle elastic scattering of protons off of spinless nuclei
Ling, A.G.
1988-07-01T23:59:59.000Z
Elastic differential cross sections and analyzing powers for 800 MeV protons incident on /sup 12/C, /sup 40/Ca, and /sup 208/Pb in the momentum transfer range 20 MeV/c < q < 130 MeV/c have been measured. The data was taken with the High Resolution Spectrometer (HRS) at the Los Alamos Meson Physics Facility. Special delay-line drift chambers with dead regions for the beam to pass through them were used to obtain the data. Through the interference of the Coulomb and nuclear contributions to the differential cross section in the small angle region, the ratio of the real to imaginary part of the forward nuclear amplitude ..cap alpha../sub n/(0) = Ref/sub n/(0)/Imf/sub n/(0) is extracted. The importance of knowing this quantity at lower energies in order to study the differences between relativistic and non-relativistic scattering theories is discussed. 130 refs., 60 figs., 12 tabs.
Spin Polarization in $?d \\to \\vec{n}p$ at Low Energies with a Pionless Effective Field Theory
S. -I. Ando; Y. -H. Song; C. H. Hyun; K. Kubodera
2011-06-01T23:59:59.000Z
With the use of pionless effective field theory including dibaryon fields, we study the $\\gamma d \\to \\vec{n} p$ reaction for the laboratory photon energy $E_\\gamma^{lab}$ ranging from threshold to 30 MeV. Our main goal is to calculate the neutron polarization $P_{y'}$ defined as $P_{y'} = (\\sigma_+ - \\sigma_-)/(\\sigma_+ + \\sigma_-)$, where $\\sigma_+$ and $\\sigma_-$ are the differential cross sections for the spin-up and spin-down neutrons, respectively, along the axis perpendicular to the reaction plane. We also calculate the total cross section as well as the differential cross section $\\sigma(\\theta)$, where $\\theta$ is the colatitude angle. Although the results for the total and differential cross sections are found to agree reasonably well with the data, the results for $P_{y'}$ show significant discrepancy with the experiment. We comment on this discrepancy.
Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins
Leigh M. Norris
2014-10-01T23:59:59.000Z
This dissertation studies spin squeezing, entanglement and decoherence in large ensembles of cold, trapped alkali atoms with hyperfine spin f interacting with optical fields. Restricting the state of each atom to a qutrit embedded in the 2f+1 dimensional hyperfine spin enables us to efficiently model the coherent and dissipative dynamics of the ensemble. This formalism also allows us to explore the effects of local control on the internal hyperfine spins of the atoms. State preparation using such control increases the entangling power of the atom-light interface for f>1/2. Subsequent control of the internal spins converts entanglement into metrologically relevant spin squeezing. In the case of squeezing by quantum nondemolition measurement, we employ a numerical search to find state preparations that maximize spin squeezing in the presence of decoherence. Dissipative dynamics on our system include optical pumping due to spontaneous emission. While most works ignore optical pumping or treat it phenomenologically, we employ a master equation derived from first principles. This work is extended to the case of an atomic ensemble interacting with a non-homogeneous paraxial probe. The geometries of the ensemble and the probe are optimized to maximize both spatial mode matching and spin squeezing.
Spontaneous Spin Ordering of a Dirac Spin Liquid in a Magnetic Field
Lee, Patrick A.
The Dirac spin liquid was proposed to be the ground state of the spin-1/2 kagomé antiferromagnets. In a magnetic field B, we show that the state with Fermi pocket is unstable to the Landau level (LL) state. The LL state ...
Evidence for spin selectivity of triplet pairs in superconducting spin valves
Banerjee, N.; Smiet, C. B.; Smits, R. G. J.; Ozaeta, A.; Bergeret, F. S.; Blamire, M. G.; Robinson, J. W. A.
2014-01-09T23:59:59.000Z
in spintronics to control the flow of electrons by ferromagnets in a ferromagnet (F1)/normal metal (N)/ferromagnet (F2) spin valve, where F1 acts as the polarizer and F2 the analyser. The feasibility of superconducting spintronics depends on the spin sensitivity...
Mass and spin content of a free relativistic particle of arbitrary spins and the group
Nikitin, Anatoly
of particles with several spins and masses which can exist in positive as well as negative energy states Postal 20-364, 01000 Mexico D. F., Mexico 2 Instituto de Ciencias Nucleares, UNAM, Apdo. Postal 70 approach to the free parti- cle of arbitrary spins whose relativistic equation can be obtained from
Massive spin-2 and spin-1/2 no hair theorems for stationary axisymmetric black holes
Sourav Bhattacharya; Amitabha Lahiri
2012-10-09T23:59:59.000Z
We present a proof of the no hair theorems corresponding to free massive non-perturbative Pauli-Fierz spin-2 and perturbative massive spin-1/2 fields for stationary axisymmetric de Sitter black hole spacetimes of dimension four with two commuting Killing vector fields. The applicability of these results for asymptotically flat and anti-de Sitter spacetimes are also discussed.
atomic resolution high-angle: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
scattering of electrons CERN Preprints Summary: We consider theoretically the energy loss of electrons scattered to high angles when assuming that the primary beam can be...
angle deposited nano-rough: Topics by E-print Network
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Materials Science Websites Summary: the deposition angle, deposition rate, ro- tation speed, and material specific parameters such as surface deposition T. Karabacak,a) G.-C....
Thermally activated switching of perpendicular magnet by spin-orbit spin torque
Lee, Ki-Seung [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Seo-Won [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Min, Byoung-Chul [Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Kyung-Jin, E-mail: kj-lee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Spin Convergence Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713 (Korea, Republic of)
2014-02-17T23:59:59.000Z
We theoretically investigate the threshold current for thermally activated switching of a perpendicular magnet by spin-orbit spin torque. Based on the Fokker-Planck equation, we obtain an analytic expression of the switching current, in agreement with numerical result. We find that thermal energy barrier exhibits a quasi-linear dependence on the current, resulting in an almost linear dependence of switching current on the log-scaled current pulse-width even below 10?ns. This is in stark contrast to standard spin torque switching, where thermal energy barrier has a quadratic dependence on the current and the switching current rapidly increases at short pulses. Our results will serve as a guideline to design and interpret switching experiments based on spin-orbit spin torque.
Spin-polarized lasing in a highly photoexcited semiconductor microcavity
Hsu, Feng-kuo; Lee, Yi-Shan; Lin, Sheng-Di; Lai, Chih-Wei
2015-01-01T23:59:59.000Z
Lasing in semiconductors is generally independent of the spins of electrons and holes, which constitute the gain medium. However, in a few spin-controlled lasers, spin-polarized carriers with long spin relaxation times ($\\sim$1 ns) result in continuous or sub-nanosecond pulsed circularly polarized stimulated emission. In these spin-controlled semiconductor lasers, a spin-imbalanced population inversion has been considered necessary. Here, we demonstrate room-temperature spin-polarized ultrafast ($\\sim$10 ps) lasing in a highly optically excited GaAs microcavity embedded with InGaAs multiple quantum wells within which the spin relaxation time is less than 10 ps. The laser radiation remains highly circularly polarized even when excited by \\emph{nonresonant} \\emph{elliptically} polarized light. In contrast to conventional semiconductor lasers, it exhibits a nonlinear input-output relation, energy shifts, and spectral broadening as a function of the photoexcited density. Such spin-polarized lasing is attributed t...
Spin dynamics in relativistic light-matter interaction
Heiko Bauke; Sven Ahrens; Christoph H. Keitel; Rainer Grobe
2015-04-14T23:59:59.000Z
Various spin effects are expected to become observable in light-matter interaction at relativistic intensities. Relativistic quantum mechanics equipped with a suitable relativistic spin operator forms the theoretical foundation for describing these effects. Various proposals for relativistic spin operators have been offered by different authors, which are presented in a unified way. As a result of the operators' mathematical properties only the Foldy-Wouthuysen operator and the Pryce operator qualify as possible proper relativistic spin operators. The ground states of highly charged hydrogen-like ions can be utilized to identify a legitimate relativistic spin operator experimentally. Subsequently, the Foldy-Wothuysen spin operator is employed to study electron-spin precession in high-intensity standing light waves with elliptical polarization. For a correct theoretical description of the predicted electron-spin precession relativistic effects due to the spin angular momentum of the electromagnetic wave has to be taken into account even in the limit of low intensities.
Electrical spin injection in 2D semiconductors and topological insulators
Golub, L. E.; Ivchenko, E. L. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, St. Petersburg (Russian Federation)
2013-12-04T23:59:59.000Z
We have developed a theory of spin orientation by electric current in 2D semiconductors. It is shown that the spin depends on the relation between the energy and spin relaxation times and can vary by a factor of two for the limiting cases of fast and slow energy relaxation. For symmetrically-doped (110)-grown semiconductor quantum wells the effect of current-induced spin orientation is shown to exist due to random spatial variation of the Rashba spin-orbit splitting. We demonstrate that the spin depends strongly on the correlation length of this random spin-orbit field. We calculate the spin orientation degree in two-dimensional topological insulators. In high electric fields when the “streaming” regime is realized, the spin orientation degree weakly depends on the electric field and can reach values about 5%.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, VISible channel, low-sun angles [a0 data is uncalibrated
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Flynn, Connor
Shortwave Array Spectroradiometer-Hemispheric, VISible channel, high-sun angles [a0 data is uncalibrated
Espinoza, A.; Beeksma, B.; Petasecca, M.; Fuduli, I.; Porumb, C.; Cutajar, D.; Lerch, M. L. F.; Rosenfeld, A. B. [Centre for Medical Radiation Physics, University of Wollongong, New South Wales 2522 (Australia)] [Centre for Medical Radiation Physics, University of Wollongong, New South Wales 2522 (Australia); Corde, S.; Jackson, M. [Department of Radiation Oncology, Prince of Wales Hospital, New South Wales 2031 (Australia)] [Department of Radiation Oncology, Prince of Wales Hospital, New South Wales 2031 (Australia)
2013-11-15T23:59:59.000Z
Purpose: High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly {sup 192}Ir with an air KERMA strength range between 20 000 and 40 000 U, where 1 U = 1 ?Gy m{sup 2}/h in air) through applicators directly into the patient's prescribed region of treatment. Due to the obvious ramifications of incorrect treatment while using such an active source, it is essential that there are methods for quality assurance (QA) that can directly and accurately verify the treatment plan and the functionality of the remote afterloader. This paper describes the feasibility study of a QA system for HDR brachytherapy using a phantom based two-dimensional 11 × 11 epitaxial diode array, named “magic phantom.”Methods: The HDR brachytherapy treatment plan is translated to the phantom with two rows of 10 (20 in total) HDR source flexible catheters, arranged above and below the diode array “magic plate” (MP). Four-dimensional source tracking in each catheter is based upon a developed fast iterative algorithm, utilizing the response of the diodes in close proximity to the {sup 192}Ir source, sampled at 100 ms intervals by a fast data acquisition (DAQ) system. Using a {sup 192}Ir source in a solid water phantom, the angular response of the developed epitaxial diodes utilized in the MP and also the variation of the MP response as a function of the source-to-detector distance (SDD) were investigated. These response data are then used by an iterative algorithm for source dwelling position determination. A measurement of the average transit speed between dwell positions was performed using the diodes and a fast DAQ.Results: The angular response of the epitaxial diode showed a variation of 15% within 360°, with two flat regions above and below the detector face with less than 5% variation. For SDD distances of between 5 and 30 mm the relative response of the epitaxial diodes used in the MP is in good agreement (within 8%) with radial dose function measurements found within the TG-43 protocol, with SDD of up to 70 mm showing a 40% over response. A method for four-dimensional localization of the HDR source was developed, allowing the source dwell position to be derived within 0.50 mm of the expected position. An estimation of the average transit speed for varying step sizes was determined and was found to increase from (12.8 ± 0.3) up to (38.6 ± 0.4) cm/s for a step size of 2.5 and 50 mm, respectively.Conclusions: Our characterization of the designed QA “magic phantom” with MP in realistic HDR photon fields demonstrates the promising performance for real-time source position tracking in four dimensions and measurements of transit times. Further development of this system will allow a full suite for QA in HDR brachytherapy and analysis, and for future in vivo tracking.
Demand Response Spinning Reserve Demonstration -- Phase 2 Findings from the Summer of 2008
Eto, Joseph H.
2010-01-01T23:59:59.000Z
A. Barat, D. Watson. 2007. Demand Response Spinning ReserveN ATIONAL L ABORATORY Demand Response Spinning Reserveemployer. LBNL-XXXXX Demand Response Spinning Reserve
New Results on Nucleon Spin Structure
Jian-Ping Chen
2005-09-10T23:59:59.000Z
Recent precision spin structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure in the valence quark (high-x) region and improved our understanding of higher-twist effects, spin sum rules and quark-hadron duality. First, results of a precision measurement of the neutron spin asymmetry, A{sub 1}{sup n}, in the high-x region are discussed. The new data shows clearly, for the first time, that A{sub 1}{sup n} becomes positive at high x. They provide crucial input for the global fits to world data to extract polarized parton distribution functions. Preliminary results on A{sub 1}{sup p} and A{sub 1}{sup d} in the high-x region have also become available. The up and down quark spin distributions in the nucleon were extracted. The results for {Delta}d/d disagree with the leading-order pQCD prediction assuming hadron helicity conservation. Then, results of a precision measurement of the g{sub 2}{sup n} structure function to study higher-twist effects are presented. The data show a clear deviation from the lead-twist contribution, indicating a significant higher-twist (twist-3 or higher) effect. The second moment of the spin structure functions and the twist-3 matrix element d{sub 2}{sup n} results were extracted at a high Q{sup 2} of 5 GeV{sup 2} from the measured A{sub 2}{sup n} in the high-x region in combination with existing world data and compared with a Lattice QCD calculation. Results for d{sub 2}{sup n} at low-to-intermediate Q{sup 2} from 0.1 to 0.9 GeV{sup 2} were also extracted from the JLab data. In the same Q{sup 2} range, the Q{sup 2} dependence of the moments of the nucleon spin structure functions was measured, providing a unique bridge linking the quark-gluon picture of the nucleon and the coherent hadronic picture. Sum rules and generalized forward spin polarizabilities were extracted and compared with Chiral Perturbation Theory calculations and phenomenological models. Finally, preliminary results on the resonance spin structure functions in the Q{sup 2} range from 1 to 4 GeV{sup 2} were presented, which, in combination with DIS data, will enable a detailed study of the quark-hadron duality in spin structure functions.
Small angle neutron scattering study of Linde 80 RPV welds
Wirth, B.D.; Odette, G.R.; Lucas, G.E. [Univ. of California, Santa Barbara, CA (United States). Dept. of Mechanical and Environmental Engineering; Pavinich, W.A. [Framatome Technologies Inc., Knoxville, TN (United States); Spooner, S.E. [Oak Ridge National Lab., TN (United States). Solid state Div.
1999-10-01T23:59:59.000Z
Small angle neutron scattering (SANS) results are presented for Linde 80 welds irradiated, as part of the B and W Owners Group Integrated Surveillance Program, at low fluxes (<10{sup 15} n/m{sup 2}-s) to fluences from 0.29 to 3.5 {times} 10{sup 23} n/m{sup 2} (E > 1 MeV) at irradiation temperatures from 276 to 292 C. The welds all contain about 0.6 Ni (all composition units are in wt.%), 0.009 to 0.18 P and 0.05 to 0.28 Cu. In the welds with significant amounts of copper (>0.2 Cu) the measured defect scattering cross sections were consistent with either: (a) copper rich precipitates (CRPs) alloyed with manganese and nickel; or (b) dominant CRP scattering, plus a weak contribution from so-called matrix defect features. Similar weak scattering was observed in a low copper (0.06 Cu) weld. The identity of matrix defect features cannot be determined from the SANS data alone, but the scattering is consistent with the presence of subnanometer vacancy cluster-solute complexes. The general character of the CRPs, and the trends in their number density, volume fraction and average radius as a function of fluence and irradiation temperature, are very similar to those observed in a wide range of pressure vessel-type steels irradiated in test reactors at intermediate to high flux. The SANS data in the surveillance welds is also in unity with: (a) thermodynamic-kinetic radiation enhanced diffusion models of CRP evolution; (b) mechanical property changes, including predictions of the correlations of the surveillance data base; and (c) an atomic scale, atom probe field ion microscopy study into the nanostructure-chemistry of a CRP.
Adaptive sparse polynomial chaos expansion based on least angle regression
Blatman, Geraud, E-mail: geraud.blatman@edf.f [Clermont Universite, IFMA, EA 3867, Laboratoire de Mecanique et Ingenieries, BP 10448, F-63000 Clermont-Ferrand (France); EDF R and D, Departement Materiaux et Mecanique des Composants, Site des Renardieres, 77250 Moret-sur-Loing cedex (France); Sudret, Bruno [Clermont Universite, IFMA, EA 3867, Laboratoire de Mecanique et Ingenieries, BP 10448, F-63000 Clermont-Ferrand (France); Phimeca Engineering, Centre d'Affaires du Zenith, 34 rue de Sarlieve, F-63800 Cournon d'Auvergne (France)
2011-03-20T23:59:59.000Z
Polynomial chaos (PC) expansions are used in stochastic finite element analysis to represent the random model response by a set of coefficients in a suitable (so-called polynomial chaos) basis. The number of terms to be computed grows dramatically with the size of the input random vector, which makes the computational cost of classical solution schemes (may it be intrusive (i.e. of Galerkin type) or non intrusive) unaffordable when the deterministic finite element model is expensive to evaluate. To address such problems, the paper describes a non intrusive method that builds a sparse PC expansion. First, an original strategy for truncating the PC expansions, based on hyperbolic index sets, is proposed. Then an adaptive algorithm based on least angle regression (LAR) is devised for automatically detecting the significant coefficients of the PC expansion. Beside the sparsity of the basis, the experimental design used at each step of the algorithm is systematically complemented in order to avoid the overfitting phenomenon. The accuracy of the PC metamodel is checked using an estimate inspired by statistical learning theory, namely the corrected leave-one-out error. As a consequence, a rather small number of PC terms are eventually retained (sparse representation), which may be obtained at a reduced computational cost compared to the classical 'full' PC approximation. The convergence of the algorithm is shown on an analytical function. Then the method is illustrated on three stochastic finite element problems. The first model features 10 input random variables, whereas the two others involve an input random field, which is discretized into 38 and 30 - 500 random variables, respectively.
Aerodynamic flail for a spinning projectile
Cole, James K. (Albuquerque, NM)
1990-01-01T23:59:59.000Z
A flail is provided which reduces the spin of a projectile in a recovery system which includes a parachute, a cable connected to the parachute, a swivel, and means for connecting the swivel to the projectile. The flail includes a plurality of flexible filaments and a rotor for attaching the filaments to the front end of the projectile. The rotor is located radially with respect to the spinning axis of the projectile. In one embodiment, the projectile includes a first nose cone section housing a deployable spin damping assembly; a second nose cone section, housing a deployable parachute assembly; a shell section, supporting the first and second nose cone sections during flight of the projectile; a mechanism for releasing the first nose cone section from the second cone section; and a mechanism for releasing the second nose cone section from the shell section. In operation of this embodiment, the deployable spin damping assembly deploys during flight of the projectile when the mechanism for releasing the first nose cone section from the second nose cone section are actuated. Then, upon actuation of the mechanism for releasing the second nose cone section from the shell section, two things happen: the spin damping assembly separates from the projectile; and the deployable parachute assembly is deployed.
Coupling spin ensembles via superconducting flux qubits
Yueyin Qiu; Wei Xiong; Lin Tian; J. Q. You
2014-09-10T23:59:59.000Z
We study a hybrid quantum system consisting of spin ensembles and superconducting flux qubits, where each spin ensemble is realized using the nitrogen-vacancy centers in a diamond crystal and the nearest-neighbor spin ensembles are effectively coupled via a flux qubit.We show that the coupling strengths between flux qubits and spin ensembles can reach the strong and even ultrastrong coupling regimes by either engineering the hybrid structure in advance or tuning the excitation frequencies of spin ensembles via external magnetic fields. When extending the hybrid structure to an array with equal coupling strengths, we find that in the strong-coupling regime, the hybrid array is reduced to a tight-binding model of a one-dimensional bosonic lattice. In the ultrastrong-coupling regime, it exhibits quasiparticle excitations separated from the ground state by an energy gap. Moreover, these quasiparticle excitations and the ground state are stable under a certain condition that is tunable via the external magnetic field. This may provide an experimentally accessible method to probe the instability of the system.
Higher Spin Currents in Wolf Space: Part III
Changhyun Ahn
2015-04-01T23:59:59.000Z
The large N=4 linear superconformal algebra (generated by four spin-1/2 currents, seven spin-1 currents, four spin-3/2 currents and one spin-2 current) found by Sevrin, Troost and Van Proeyen (and other groups) was realized in the N=4 superconformal coset SU(5)/SU(3) theory previously. The lowest 16 higher spin currents of spins (1, 3/2, 3/2, 2), (3/2, 2, 2, 5/2), (3/2, 2, 2, 5/2) and (2, 5/2, 5/2, 3) are obtained by starting with the operator product expansions (OPEs) between the four spin-3/2 currents from the above large N=4 linear superconformal algebra and the lowest higher spin-1 current which is the same as the one in the Wolf space coset SU(5)/[SU(3) x SU(2) x U(1)] theory. These OPEs determine the four higher spin-3/2 currents and the next six higher spin-2 currents are obtained from the OPEs between the above four spin-3/2 currents associated with the N=4 supersymmetry and these four higher spin-3/2 currents. The four higher spin-5/2 currents can be determined by calculating the OPEs between the above four spin-3/2 currents and the higher spin-2 currents. Similarly, the higher spin-3 current is obtained from the OPEs between the four spin-3/2 currents and the higher spin-5/2 currents. The explicit relations between the above 16 higher spin currents and the corresponding 16 higher spin currents which were found in the extension of large N=4 nonlinear superconformal algebra previously are given. By examining the OPEs between the 16 currents from the large N=4 linear superconformal algebra and the 16 higher spin currents, the match with the findings of Beccaria, Candu and Gaberdiel is also given. The next 16 higher spin currents of spins (2, 5/2, 5/2, 3), (5/2, 3, 3, 7/2), (5/2, 3, 3, 7/2) and (3, 7/2, 7/2, 4) occur from the OPEs between the above lowest 16 higher spin currents.
Electron spin magnetism of zigzag graphene nanoribbon edge states
Xu, Kun, E-mail: xu83@purdue.edu; Ye, Peide D. [School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)
2014-04-21T23:59:59.000Z
The electron spin states of zigzag graphene nanoribbon (ZGNR) edge play a pivotal role in the applications of graphene nanoribbons. However, the exact arrangements of the electron spins remain unclear to date. In this report, the electronic spin states of the ZGNR edge have been elucidated through a combination of quantum chemical investigation and previous electron spin resonance experiment observations. An alternating ? and ? spin configuration of the unpaired electrons along the ZGNR edge is established in ambient condition without any external magnetic field, and the origin of the spin magnetism of the ZGNR edge is revealed. It paves a pathway for the understanding and design of graphene based electronic and spintronic devices.
Spin-dependent terahertz oscillator based on hybrid graphene superlattices
Díaz, E.; Miralles, K.; Domínguez-Adame, F. [GISC, Departamento Física de Materiales, Universidad Complutense, E-28040 Madrid (Spain); Gaul, C., E-mail: cgaul@pks.mpg.de [Max Planck Institute for the Physics of Complex Systems, 01187 Dresden (Germany)
2014-09-08T23:59:59.000Z
We theoretically study the occurrence of Bloch oscillations in biased hybrid graphene systems with spin-dependent superlattices. The spin-dependent potential is realized by a set of ferromagnetic insulator strips deposited on top of a gapped graphene nanoribbon, which induce a proximity exchange splitting of the electronic states in the graphene monolayer. We numerically solve the Dirac equation and study Bloch oscillations in the lowest conduction band of the spin-dependent superlattice. While the Bloch frequency is the same for both spins, we find the Bloch amplitude to be spin dependent. This difference results in a spin-polarized ac electric current in the THz range.
Group manifold approach to higher spin theory
Hu, Shan
2015-01-01T23:59:59.000Z
We consider the group manifold approach to higher spin theory. The deformed higher spin transformation is realized as the diffeomorphism transformation on group manifold $\\textbf{M}$. With the suitable rheonomy condition and the torsion constraint imposed, the unfolded equation can be obtained from the Bianchi identity, by solving which, fields on $\\textbf{M}$ is determined by the multiplet at one point, or equivalently, by $(W^{[a(s-1),b(0)]}_{\\mu},H)$ on $AdS_{4}\\subset \\textbf{M}$. Although the space is extended to $\\textbf{M}$ to get the geometrical formulation, the dynamical degrees of freedom is still in $AdS_{4}$. We also discuss the theory with the global higher spin symmetry, which is in parallel with the WZ model in supersymmetry.
The Jefferson Lab Frozen Spin Target
Christopher Keith, James Brock, Christopher Carlin, Sara Comer, David Kashy, Josephine McAndrew, David Meekins, Eugene Pasyuk, Joshua Pierce, Mikell Seely
2012-08-01T23:59:59.000Z
A frozen spin polarized target, constructed at Jefferson Lab for use inside a large acceptance spectrometer, is described. The target has been utilized for photoproduction measurements with polarized tagged photons of both longitudinal and circular polarization. Protons in TEMPO-doped butanol were dynamically polarized to approximately 90% outside the spectrometer at 5 T and 200-300 mK. Photoproduction data were acquired with the target inside the spectrometer at a frozen-spin temperature of approximately 30 mK with the polarization maintained by a thin, superconducting coil installed inside the target cryostat. A 0.56 T solenoid was used for longitudinal target polarization and a 0.50 T dipole for transverse polarization. Spin relaxation times as high as 4000 hours were observed. We also report polarization results for deuterated propanediol doped with the trityl radical OX063.
Quantum Optics of Chiral Spin Networks
Hannes Pichler; Tomás Ramos; Andrew J. Daley; Peter Zoller
2015-04-15T23:59:59.000Z
We study the driven-dissipative dynamics of a network of spin-1/2 systems coupled to one or more chiral 1D bosonic waveguides within the framework of a Markovian master equation. We determine how the interplay between a coherent drive and collective decay processes can lead to the formation of pure multipartite entangled steady states. The key ingredient for the emergence of these many-body dark states is an asymmetric coupling of the spins to left and right propagating guided modes. Such systems are motived by experimental possibilities with internal states of atoms coupled to optical fibers, or motional states of trapped atoms coupled to a spin-orbit coupled Bose-Einstein condensate. We discuss the characterization of the emerging multipartite entanglement in this system in terms of the Fisher information.
Higher Spin Currents in Wolf Space: Part III
Ahn, Changhyun
2015-01-01T23:59:59.000Z
The large N=4 linear superconformal algebra (generated by four spin-1/2 currents, seven spin-1 currents, four spin-3/2 currents and one spin-2 current) found by Sevrin, Troost and Van Proeyen (and other groups) was realized in the N=4 superconformal coset SU(5)/SU(3) theory previously. The lowest 16 higher spin currents of spins (1, 3/2, 3/2, 2), (3/2, 2, 2, 5/2), (3/2, 2, 2, 5/2) and (2, 5/2, 5/2, 3) are obtained by starting with the operator product expansions (OPEs) between the four spin-3/2 currents from the above large N=4 linear superconformal algebra and the lowest higher spin-1 current which is the same as the one in the Wolf space coset SU(5)/[SU(3) x SU(2) x U(1)] theory. These OPEs determine the four higher spin-3/2 currents and the next six higher spin-2 currents are obtained from the OPEs between the above four spin-3/2 currents associated with the N=4 supersymmetry and these four higher spin-3/2 currents. The four higher spin-5/2 currents can be determined by calculating the OPEs between the abo...
29 Nov 2001 A. Bacchetta -Fragmentation to probe transversity 31 Hadron pair azimuthal angle
1 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 31 Hadron pair azimuthal angle 29 Nov 2001 A. Bacchetta - Fragmentation to probe transversity 32 Center of mass angle hadron decay plane Center of mass direction in lab frame Center of mass frame R #12;2 29 Nov 2001 A. Bacchetta
Adhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays with
Goldstein, Seth Copen
in a synthetic dry angled fibrillar adhesive sample (spatula tip fiber sample). The direction dependent frictionAdhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays and spatula shaped tips via dipping. These fibers are characterized for adhesion and friction and compared
SAYA's head-eye coordination system Correspondence of image-width and angle
Beimel, Amos
SAYA's head-eye coordination system Correspondence of image-width and angle 335 - 359 [deg] 0 - 25 - 25 [deg] is input, head and eyes move to right side. b) If the angle within 335 - 359 [deg] is input, head and eyes move to left side. SAYA's head-eye coordination system Correspondence of image
Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory
Weston, Ken
Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory NMR Spectroscopy spectra. #12;Spectral Mapping of Protein Torsion Angles National High Magnetic Field Laboratory NMR, in recording signals that are dependent on the orientation of the atoms with respect to the magnetic field, we
Zender, Charles
Constraining MODIS snow albedo at large solar zenith angles: Implications for surface energy budget; Solar Zenith Angle; Greenland; Surface Energy Budget 2 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 plays a pivotal role in determining the surface energy balance of Greenland which, by virtue of its area
Factors that control the angle of shear bands in geodynamic numerical models of brittle deformation
Kaus, Boris
timescales typically use a pressure-dependent (Mohr Coulomb or DruckerPrager) plastic flow law to simulate University of Southern California, Los Angeles, USA a b s t r a c ta r t i c l e i n f o Article history work suggest that both Roscoe (45°), Coulomb angles (45+/-/2, where is the angle of internal friction
Carlson, Erica
Thermoelectric figure of merit as a function of carrier propagation angle in semiconducting;Thermoelectric figure of merit as a function of carrier propagation angle in semiconducting superlattices Shuo a fruitful approach for enhancing the figure of merit, ZT, of thermoelectric materials. Generally
Light is said to be reflected when the angle at which light
Gilbes, Fernando
1 #12;2 Light is said to be reflected when the angle at which light initially strikes a surface is equal to the angle at which light bounces off the same surface. In the diagram, light strikes a surface", this is an example of reflected light. Refraction is the bending of a wave when it enters a medium where it's speed
Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated
Wang, Howard "Hao"
Small angle neutron scattering from single-wall carbon nanotube suspensions: evidence for isolated online: Abstract We report small angle neutron scattering (SANS) from dilute suspensions of purified University, Houghton, MI 49931, USA e NIST Center for Neutron Research, National Institute of Standards
Small angle neutron scattering on periodically deformed polymers A. R. Rennie
Boyer, Edmond
765 Small angle neutron scattering on periodically deformed polymers A. R. Rennie Institut für Phys-768 SEPTEMBRE 1984, 1. Introduction. Neutron scattering has proved a useful tool for the investigation of a wide time for a small angle neutron scattering spectrum is several minutes. Obser- vation on rapidly
Salt-Dependent Compaction of Di-and Trinucleosomes Studied by Small-Angle Neutron Scattering
Langowski, Jörg
Salt-Dependent Compaction of Di- and Trinucleosomes Studied by Small-Angle Neutron Scattering, Germany, and Institut Laue-Langevin Grenoble, F-38042 Grenoble, France ABSTRACT Using small-angle neutron scattering (SANS), we have measured the salt-dependent static structure factor of di- and trinucleosomes from
High temperature furnaces for small and large angle neutron scattering of disordered materials
Boyer, Edmond
725 High temperature furnaces for small and large angle neutron scattering of disordered materials and small angle neutron scattering (SANS) experiments respectively. They are vacuum furnaces with a thin maintained in a tantalum box. In a neutron beam, the furnaces produce a very low scattering level (without
Kilpatrick, Peter K.
-Angle Neutron Scattering Keith L. Gawrys, George A. Blankenship, and Peter K. Kilpatrick* Department of ChemicalVed September 14, 2005. In Final Form: January 30, 2006 While small-angle neutron scattering (SANS) has proven to the scattering intensity curves were performed using the Guinier approximation, the Ornstein- Zernike (or Zimm
Wuttke, Joachim; Zamponi, Michaela [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85747 Garching (Germany)] [Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at MLZ, Lichtenbergstraße 1, 85747 Garching (Germany)
2013-11-15T23:59:59.000Z
The resolution of neutron backscattering spectrometers deteriorates at small scattering angles where analyzers deviate from exact backscattering. By reducing the azimuth angle range of the analyzers, the resolution can be improved with little loss of peak intensity. Measurements at the spectrometer SPHERES are in excellent agreement with simulations, which proves the dominance of geometric effects.
Small angle neutron scattering (SANS) under non-equilibrium conditions R. C. Oberthr
Boyer, Edmond
663 Small angle neutron scattering (SANS) under non-equilibrium conditions R. C. Oberthür Institut with the times obtained from quasi- elastic neutron and light scattering, which yield information about neutrons aux petits angles (DNPA) pour l'étude des systèmes hors d'équi- libre thermodynamique est
Electron Spin Resonance Spectroscopy via Relaxation of Solid-State Spin Probes at the Nanoscale
L. T. Hall; P. Kehayias; D. A. Simpson; A. Jarmola; A. Stacey; D. Budker; L. C. L. Hollenberg
2015-03-03T23:59:59.000Z
Electron Spin Resonance (ESR) describes a suite of techniques for characterising electronic systems, with applications in physics, materials science, chemistry, and biology. However, the requirement for large electron spin ensembles in conventional ESR techniques limits their spatial resolution. Here we present a method for measuring the ESR spectrum of nanoscale electronic environments by measuring the relaxation time ($T_1$) of an optically addressed single-spin probe as it is systematically tuned into resonance with the target electronic system. As a proof of concept we extract the spectral distribution for the P1 electronic spin bath in diamond using an ensemble of nitrogen-vacancy centres, and demonstrate excellent agreement with theoretical expectations. As the response of each NV spin in this experiment is dominated by a single P1 spin at a mean distance of 2.7\\,nm, the extension of this all-optical technique to the single NV case will enable nanoscale ESR spectroscopy of atomic and molecular spin systems.
Angle-resolved photoemission spectroscopy (ARPES) studies of cuprate superconductors
Palczewski, Ari Deibert
2010-12-15T23:59:59.000Z
This dissertation is comprised of three different angle-resolved photoemission spectroscopy (ARPES) studies on cuprate superconductors. The first study compares the band structure from two different single layer cuprates Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl2201) T{sub c,max} {approx} 95 K and (Bi{sub 1.35}Pb{sub 0.85})(Sr{sub 1.47}La{sub 0.38})CuO{sub 6+{delta}} (Bi2201) T{sub c,max} {approx} 35 K. The aim of the study was to provide some insight into the reasons why single layer cuprate's maximum transition temperatures are so different. The study found two major differences in the band structure. First, the Fermi surface segments close to ({pi},0) are more parallel in Tl2201 than in Bi2201. Second, the shadow band usually related to crystal structure is only present in Bi2201, but absent in higher T{sub c} Tl2201. The second study looks at the different ways of doping Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi2212) in-situ by only changing the post bake-out vacuum conditions and temperature. The aim of the study is to systematically look into the generally overlooked experimental conditions that change the doping of a cleaved sample in ultra high vacuum (UHV) experiments. The study found two major experimental facts. First, in inadequate UHV conditions the carrier concentration of Bi2212 increases with time, due to the absorption of oxygen from CO{sub 2}/CO molecules, prime contaminants present in UHV systems. Second, in a very clean UHV system at elevated temperatures (above about 200 K), the carrier concentration decreases due to the loss of oxygen atoms from the Bi-O layer. The final study probed the particle-hole symmetry of the pseudogap phase in high temperature superconducting cuprates by looking at the thermally excited bands above the Fermi level. The data showed a particle-hole symmetric pseudogap which symmetrically closes away from the nested FS before the node. The data is consistent with a charge density wave (CDW) origin of the pseudogap, similar to STM checkerboard patterns in the pseudogap state.
Time resolved spin Seebeck effect experiments
Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de; Schreier, Michael; Schade, Felix; Ganzhorn, Kathrin; Meyer, Sibylle; Geprägs, Stephan [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Kamra, Akashdeep [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Huebl, Hans; Goennenwein, Sebastian T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich (NIM), Munich (Germany); Gross, Rudolf [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Nanosystems Initiative Munich (NIM), Munich (Germany)
2014-05-19T23:59:59.000Z
In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our thin film hybrid structures.
Spin, Statistics, and Reflections, II. Lorentz Invariance
Bernd Kuckert; Reinhard Lorenzen
2005-12-21T23:59:59.000Z
The analysis of the relation between modular P$_1$CT-symmetry -- a consequence of the Unruh effect -- and Pauli's spin-statistics relation is continued. The result in the predecessor to this article is extended to the Lorentz symmetric situation. A model $\\G_L$ of the universal covering $\\widetilde{L_+^\\uparrow}\\cong SL(2,\\complex)$ of the restricted Lorentz group $L_+^\\uparrow$ is modelled as a reflection group at the classical level. Based on this picture, a representation of $\\G_L$ is constructed from pairs of modular P$_1$CT-conjugations, and this representation can easily be verified to satisfy the spin-statistics relation.
Neutron single target spin asymmetries in SIDIS
Evaristo Cisbani
2010-04-01T23:59:59.000Z
The experiment E06-010 in Hall A at Jefferson Lab took data between November 2008 and February 2009 to directly measure, for the first time, the pion (and kaon) single "neutron" target-spin asymmetry (SSA) in semi-inclusive DIS from a polarized 3He target. Collins, Sivers (and Pretzelosity) neutron asymmetries are going to be extracted from the measured SSA. Details of the experiment are described together with the preliminary results of the ongoing analysis. Near future Hall A experiments on transverse nucleon spin structure are shorty reviewed.
Spinning Fluids: A Group Theoretical Approach
Dario Capasso; Debajyoti Sarkar
2014-04-07T23:59:59.000Z
We extend the Lagrangian formulation of relativistic non-abelian fluids in group theory language. We propose a Mathisson-Papapetrou equation for spinning fluids in terms of the reduction limit of de Sitter group. The equation we find correctly boils down to the one for non-spinning fluids. We study the application of our results for an FRW cosmological background for fluids with no vorticity and for dusts in the vicinity of a Kerr black hole. We also explore two alternative approaches based on a group theoretical formulation of particles dynamics.
J. Albert et al.
2005-08-25T23:59:59.000Z
The MAGIC Cherenkov telescope has observed very high energy (VHE) gamma-ray emission from the Active Galactic Nucleus 1ES1959+650 during six hours in September and October 2004. The observations were carried out alternated with the Crab Nebula, whose data were used as reference source for optimizing gamma/hadron separation and for flux comparison. The data analysis shows VHE gamma-ray emission of 1ES1959+650 with ~ 8 sigma significance, at a time of low activity in both optical and X-ray wavelengths. An integral flux above ~ 180 GeV of about 20% of the Crab was obtained. The light curve, sampled over 7 days, shows no significant variations. The differential energy spectrum between 180 GeV and 2 TeV can be fitted with a power law of index -2.72 +/- 0.14. The spectrum is consistent with the slightly steeper spectrum seen by HEGRA at higher energies, also during periods of low X-ray activity.
Scattering of Spin-Zero and Spin-Half Particles in Momentum-Helicity Basis
I. Fachruddin; I. Abdulrahman
2007-12-07T23:59:59.000Z
Scattering of 2 particles of spin 0 and 1/2 is evaluated based on a basis constructed from the momentum and the helicity states (the momentum-helicity basis). This shortly called three-dimensional (3D) technique is a good alternative to the standard partial wave (PW) technique especially for higher energies, where PW calculations may become not feasible. Taking as input a simple spin-orbit potential model we calculate as an example the spin averaged differential cross section and polarization.
Spin-transfer switching of orthogonal spin-valve devices at cryogenic temperatures
Ye, L., E-mail: ly17@nyu.edu; Gopman, D. B.; Rehm, L.; Backes, D.; Wolf, G.; Kent, A. D. [Department of Physics, New York University, New York, New York 10003 (United States); Ohki, T. [Raytheon BBN Technologies, Cambridge, Massachusetts 02138 (United States); Kirichenko, A. F.; Vernik, I. V.; Mukhanov, O. A. [HYPRES, 175 Clearbrook Road, Elmsford, New York 10523 (United States)
2014-05-07T23:59:59.000Z
We present the quasi-static and dynamic switching characteristics of orthogonal spin-transfer devices incorporating an out-of-plane magnetized polarizing layer and an in-plane magnetized spin valve device at cryogenic temperatures. Switching at 12?K between parallel and anti-parallel spin-valve states is investigated for slowly varied current as well as for current pulses with durations as short as 200 ps. We demonstrate 100% switching probability with current pulses 0.6?ns in duration. We also present a switching probability diagram that summarizes device switching operation under a variety of pulse durations, amplitudes, and polarities.
Reduced matrix elements of spin–spin interactions for the atomic f-electron configurations
Yeung, Y.Y., E-mail: yeungy@acm.org
2014-03-15T23:59:59.000Z
A re-examination of some major references on the intra-atomic magnetic interactions over the last six decades reveals that there exist some gaps or puzzles concerning the previous studies of the spin–spin interactions for the atomic f-shell electrons. Hence, tables are provided for the relevant reduced matrix elements of the four double-tensor operators z{sub r} (r=1,2,3, and 4) of rank 2 in both the orbital and spin spaces. The range of the tables covers all states of the configurations from f{sup 4} to f{sup 7}.
Leading Edge Spinning the Web of Cell Fate
Corces, Victor G.
Leading Edge Minireview Spinning the Web of Cell Fate Kevin Van Bortle1 and Victor G. Corces1,* 1 involved in spinning the web of cell fate. Chromatin at the Nuclear Lamina The nuclear lamina is a thin
acoustic electron spin resonance: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of electrons with spin-up and electrons with spin-down. In terms of new model we consider propagation of waves in magnetized plasmas of degenerate electrons and motionless ions. We...
Power dependence of pure spin current injection by quantum interference
Ruzicka, Brian Andrew; Zhao, Hui
2009-04-01T23:59:59.000Z
We investigate the power dependence of pure spin current injection in GaAs bulk and quantumwell samples by a quantum interference and control technique. Spin separation is measured as a function of the relative strength of the two transition...
Electron spin decoherence in isotope-enriched silicon
Wayne M. Witzel; Malcolm S. Carroll; Andrea Morello; Lukasz Cywinski; S. Das Sarma
2010-10-27T23:59:59.000Z
Silicon is promising for spin-based quantum computation because nuclear spins, a source of magnetic noise, may be eliminated through isotopic enrichment. Long spin decoherence times, $T_2$, have been measured in isotope-enriched silicon but come far short of the $T_2 = 2 T_1$ limit. The effect of nuclear spins on $T_2$ is well established. However, the effect of background electron spins from ever present residual phosphorus impurities in silicon can also produce significant decoherence. We study spin decoherence decay as a function of donor concentration, $^{29}$Si concentration, and temperature using cluster expansion techniques specifically adapted to the problem of a sparse dipolarly coupled electron spin bath. Our results agree with the existing experimental spin echo data in Si:P and establish the importance of background dopants as the ultimate decoherence mechanism in isotope-enriched silicon.
arterial spin labelling: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A proposal is outlined to probe spin-charge separation in the normal state of the high Tc cuprates using spin transport. Specifically, the proposal is to compare the temperature...
arterial spin labeled: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A proposal is outlined to probe spin-charge separation in the normal state of the high Tc cuprates using spin transport. Specifically, the proposal is to compare the temperature...
arterial spin labeling: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
A proposal is outlined to probe spin-charge separation in the normal state of the high Tc cuprates using spin transport. Specifically, the proposal is to compare the temperature...
Quantum spin Hall effect and topological insulators for light
Bliokh, Konstantin Y
2015-01-01T23:59:59.000Z
We show that free-space light has intrinsic quantum spin-Hall effect (QSHE) properties. These are characterized by a non-zero topological spin Chern number, and manifest themselves as evanescent modes of Maxwell equations. The recently discovered transverse spin of evanescent modes demonstrates spin-momentum locking stemming from the intrinsic spin-orbit coupling in Maxwell equations. As a result, any interface between free space and a medium supporting surface modes exhibits QSHE of light with opposite transverse spins propagating in opposite directions. In particular, we find that usual isotropic metals with surface plasmon-polariton modes represent natural 3D topological insulators for light. Several recent experiments have demonstrated transverse spin-momentum locking and spin-controlled unidirectional propagation of light at various interfaces with evanescent waves. Our results show that all these experiments can be interpreted as observations of the QSHE of light.
Coherent Control of a Single Silicon-29 Nuclear Spin Qubit
Jarryd J. Pla; Fahd A. Mohiyaddin; Kuan Y. Tan; Juan P. Dehollain; Rajib Rahman; Gerhard Klimeck; David N. Jamieson; Andrew S. Dzurak; Andrea Morello
2014-08-06T23:59:59.000Z
Magnetic fluctuations caused by the nuclear spins of a host crystal are often the leading source of decoherence for many types of solid-state spin qubit. In group-IV materials, the spin-bearing nuclei are sufficiently rare that it is possible to identify and control individual host nuclear spins. This work presents the first experimental detection and manipulation of a single $^{29}$Si nuclear spin. The quantum non-demolition (QND) single-shot readout of the spin is demonstrated, and a Hahn echo measurement reveals a coherence time of $T_2 = 6.3(7)$ ms - in excellent agreement with bulk experiments. Atomistic modeling combined with extracted experimental parameters provides possible lattice sites for the $^{29}$Si atom under investigation. These results demonstrate that single $^{29}$Si nuclear spins could serve as a valuable resource in a silicon spin-based quantum computer.
Electron-spin dynamics in elliptically polarized light waves
Heiko Bauke; Sven Ahrens; Rainer Grobe
2014-11-03T23:59:59.000Z
We investigate the coupling of the spin angular momentum of light beams with elliptical polarization to the spin degree of freedom of free electrons. It is shown that this coupling, which is of similar origin as the well-known spin-orbit coupling, can lead to spin precession. The spin-precession frequency is proportional to the product of the laser-field's intensity and its spin density. The electron-spin dynamics is analyzed by employing exact numerical methods as well as time-dependent perturbation theory based on the fully relativistic Dirac equation and on the nonrelativistic Pauli equation that is amended by a relativistic correction that accounts for the light's spin density.
Nutation in the spinning SPHERES spacecraft and fluid slosh
Burke, Caley Ann
2010-01-01T23:59:59.000Z
Spacecraft today are often spin-stabilized during a portion their launch or mission. Though the basics of spin stabilization are well understood, there remains uncertainty in predicting the likelihood of rapid nutation ...
Competing spin pumping effects in magnetic hybrid structures
Azevedo, A., E-mail: aac@df.ufpe.br; Alves Santos, O.; Fonseca Guerra, G. A.; Cunha, R. O.; Rezende, S. M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Rodríguez-Suárez, R. [Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile)
2014-02-03T23:59:59.000Z
Pure spin current can be detected by its conversion into charge current in nanometer thick nonmagnetic metal layer with large spin-orbit coupling by means of the inverse spin Hall effect (ISHE). Recently, it has been shown that the metallic ferromagnet Permalloy (Py) can also be used as spin current detector in experiments in which an ISHE voltage is created in a Py layer in contact with the insulating ferromagnet yttrium iron garnet (YIG) under a thermal gradient in the longitudinal spin Seebeck configuration. Here, we report experiments with microwave driven spin pumping in heterostructures made with single crystal YIG film and a nanometer thick Py or Pt layer that show that Py behaves differently than nonmagnetic metals as a spin current detector. The results are attributed to the competition between the spin currents generated by the dynamics of the magnetizations in YIG and in Py, which are exchange coupled at the interface.
NMR dynamics of quantum discord for spin-carrying gas molecules in a closed nanopore
Yurishchev, M. A., E-mail: yur@itp.ac.ru [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)
2014-11-15T23:59:59.000Z
A local orthogonal transformation that transforms any centrosymmetric density matrix of a two-qubit system to the X form has been found. A piecewise-analytic-numerical formula Q = min(Q{sub ?/2}, Q{sub ?}, Q{sub 0}), where Q{sub ?/2} and Q{sub 0} are analytical expressions and the branch Q{sub 0?} can be obtained only by numerically searching for the optimal measurement angle ? ? (0, ?/2), is proposed to calculate the quantum discord Q of a general X state. The developed approaches have been applied for a quantitative description of the recently predicted flickering (periodic disappearance and reappearance) of the quantum-information pair correlation between nuclear 1/2 spins of atoms or molecules of a gas (for example, {sup 129}Xe) in a bounded volume in the presence of a strong magnetic field.
Magnetization dynamics and spin diffusion in semiconductors and metals
Cywi?ski, ?ukasz
2007-01-01T23:59:59.000Z
to (III,Mn)V ferromagnetic semiconductors . . . . . . . . .semiconductors . . . . . . . . . . . . . . . . . .Spin di?usion in semiconductors and metals: a general
Chaotic orbits for spinning particles in Schwarzschild spacetime
Verhaaren, Chris; Hirschmann, Eric W. [Physics Department, Brigham Young University, Provo, Utah 84602 (United States)
2010-06-15T23:59:59.000Z
We consider the orbits of particles with spin in the Schwarzschild spacetime. Using the Papapetrou-Dixon equations of motion for spinning particles, we solve for the orbits and focus on those that exhibit chaos using both Poincare maps and Lyapunov exponents. In particular, we develop a method for comparing the Lyapunov exponents of chaotic orbits. We find chaotic orbits for smaller spin values than previously thought and find chaotic orbits with astrophysically relevant spin values.
condmat/9801215 Crossovers in the Two Dimensional Ising Spin Glass
Roma "La Sapienza", Università di
condmat/9801215 v2 26 Jan 1998 Crossovers in the Two Dimensional Ising Spin Glass of extensive computer simulations we analyze in detail the two dimen sional \\SigmaJ Ising spin glass with ferromagnetic nextnearestneighbor interactions. We found a crossover from ferromagnetic to ``spin glass'' like
MOTT INSULATORS, SPIN LIQUIDS AND QUANTUM DISORDERED SUPERCONDUCTIVITY
COURSE 7 MOTT INSULATORS, SPIN LIQUIDS AND QUANTUM DISORDERED SUPERCONDUCTIVITY MATTHEW P.A. FISHER insulators and quantum magnetism 583 3.1 Spin models and quantum magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637 #12;MOTT INSULATORS, SPIN LIQUIDS AND QUANTUM DISORDERED SUPERCONDUCTIVITY Matthew P.A. Fisher
Lithographically directed deposition of silica nanoparticles using spin coating
New Mexico, University of
Lithographically directed deposition of silica nanoparticles using spin coating Deying Xia and S. R-assembly by spin coating to control particle placement. Three sizes of silica nanoparticles (mean diameters: 78, 50, and 15 nm) were employed for spin-coating processes. Single linear silica particle chain patterns
DIFFUSION INELASTIQUE DES AIEUTRONS ET ONDES DE SPIN
Boyer, Edmond
measured in the three principal symmetry directions by neutron inelastic scattering.The spin wave of neutrons C(Eogo)scattered by a spin wave of energy Eo and wave vector qo satisfies the following diffusion inklastiquedes neutrons. On a trouvB que les relations de dispersion des ondes de spin
ATTITUDE STABILITY OF FLEXIBLE ASYMMETRIC DUAL-SPIN SPACECRAFT
connected together by a flexible joint. The equations of motion represent a flexible multiple when either the rotor spin frequency or the platform spin frequency is in the neighborhood of a natural of dual-spin spacecraft has been studied by several investigators 1 * 2 * a - Using the energy sink
Coordinate Bethe Ansatz for Spin s XXX Model
Nicolas Crampé; Eric Ragoucy; Ludovic Alonzi
2011-01-12T23:59:59.000Z
We compute the eigenfunctions and eigenvalues of the periodic integrable spin s XXX model using the coordinate Bethe ansatz. To do so, we compute explicitly the Hamiltonian of the model. These results generalize what has been obtained for spin 1/2 and spin 1 chains.
Avalanche spin-valve transistor K. J. Russell,a)
Russell, Kasey
Avalanche spin-valve transistor K. J. Russell,a) Ian Appelbaum,b) Wei Yi, D. J. Monsma, F. Capasso, California 93106 (Received 11 June 2004; accepted 10 September 2004) A spin-valve transistor with a Ga allow fabrication of spin-valve transistors with high gain in a variety of materials. © 2004 American
Spin-valve photodiode Ian Appelbaum,a)
Russell, Kasey
Spin-valve photodiode Ian Appelbaum,a) D. J. Monsma, K. J. Russell, V. Narayanamurti, and C. M; accepted 28 August 2003 An optical spin-valve effect is observed using sub-bandgap internal photoemission the ``spin-valve'' effect SVE , because the relative magnetizations of these layers, and thus the flow
Quantum Gravity in Three Dimensions from Higher-Spin Holography
Tan, Hai Siong
2013-01-01T23:59:59.000Z
Higher Spin Anti-de Sitter Gravity,” JHEP 1012, 007 (2010)gravity in three dimensions from the per- spective of higher-spin holography in anti-gravity in three dimen- sions in the framework of higher-spin holography in anti-