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1

Quantum Hall Effect in Hydrogenated Graphene  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Magnetometer for the NHMFL DC Field Facility 07 Quantum Hall Effect in Hydrogenated Graphene 08 Spin Phase Transition in Bilayer Graphene at Charge Neutrality 09...

2

Unconventional Integer Quantum Hall effect in graphene  

E-Print Network [OSTI]

Monolayer graphite films, or graphene, have quasiparticle excitations that can be described by 2+1 dimensional Dirac theory. We demonstrate that this produces an unconventional form of the quantized Hall conductivity $\\sigma_{xy} = - (2 e^2/h)(2n+1)$ with $n=0,1,...$, that notably distinguishes graphene from other materials where the integer quantum Hall effect was observed. This unconventional quantization is caused by the quantum anomaly of the $n=0$ Landau level and was discovered in recent experiments on ultrathin graphite films.

V. P. Gusynin; S. G. Sharapov

2005-08-16T23:59:59.000Z

3

The Quantum Hall Effect in Graphene  

E-Print Network [OSTI]

We investigate the quantum Hall effect in graphene. We argue that in graphene in presence of an external magnetic field there is dynamical generation of mass by a rearrangement of the Dirac sea. We show that the mechanism breaks the lattice valley degeneracy only for the $n=0$ Landau levels and leads to the new observed $\

Paolo Cea

2012-04-24T23:59:59.000Z

4

Topological insulators in silicene: Quantum hall, quantum spin hall and quantum anomalous hall effects  

SciTech Connect (OSTI)

Silicene is a monolayer of silicon atoms forming a two-dimensional honeycomb lattice, which shares almost every remarkable property with graphene. The low energy dynamics is described by Dirac electrons, but they are massive due to relatively large spin-orbit interactions. I will explain the following properties of silicene: 1) The band structure is controllable by applying an electric field. 2) Silicene undergoes a phase transition from a topological insulator to a band insulator by applying external electric field. 3) The topological phase transition can be detected experimentally by way of diamagnetism. 4) There is a novel valley-spin selection rules revealed by way of photon absorption. 5) Silicene yields a remarkably many phases such as quantum anomalous Hall phase and valley polarized metal when the exchange field is additionally introduced. 6) A silicon nanotubes can be used to convey spin currents under an electric field.

Ezawa, Motohiko [Department of Applied Physics, University of Tokyo, Hongo 7-3-1, Tokyo 113-8656 (Japan)

2013-12-04T23:59:59.000Z

5

Planck's quantum-driven integer quantum Hall effect in chaos  

E-Print Network [OSTI]

The integer quantum Hall effect (IQHE) and chaos are commonly conceived as being unrelated. Contrary to common wisdoms, we find in a canonical chaotic system, the kicked spin-$1/2$ rotor, a Planck's quantum($h_e$)-driven phenomenon bearing a firm analogy to IQHE but of chaos origin. Specifically, the rotor's energy growth is unbounded ('metallic' phase) for a discrete set of critical $h_e$-values, but otherwise bounded ('insulating' phase). The latter phase is topological in nature and characterized by a quantum number ('quantized Hall conductance'). The number jumps by unity whenever $h_e$ decreases passing through each critical value. Our findings, within the reach of cold-atom experiments, indicate that rich topological quantum phenomena may emerge from chaos.

Yu Chen; Chushun Tian

2014-09-18T23:59:59.000Z

6

Strong Correlation Effects in Graphene in the Quantum Hall Regime  

E-Print Network [OSTI]

Strong Correlation Effects in Graphene in the Quantum Hall Regime Mark Oliver Goerbig 16 June 2008;Graphene = 2D Graphite 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 degeneracy: spin valley Energy electrons holes k k k ky x x yK' K K' K K K' #12;Correlations in graphene

Paris-Sud 11, Université de

7

Quantum Hall effect in graphene decorated with disordered multilayer patches  

SciTech Connect (OSTI)

Quantum Hall effect (QHE) is observed in graphene grown by chemical vapour deposition using platinum catalyst. The QHE is even seen in samples which are irregularly decorated with disordered multilayer graphene patches and have very low mobility (<500 cm{sup 2}V{sup ?1}s{sup ?1}). The effect does not seem to depend on electronic mobility and uniformity of the resulting material, which indicates the robustness of QHE in graphene.

Nam, Youngwoo, E-mail: youngwoo.nam@chalmers.se [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of) [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Sun, Jie, E-mail: jie.sun@chalmers.se; Lindvall, Niclas; Kireev, Dmitry; Yurgens, August [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden)] [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Jae Yang, Seung; Rae Park, Chong [Department of Materials Science and Engineering, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Department of Materials Science and Engineering, Seoul National University, Seoul 151-747 (Korea, Republic of); Woo Park, Yung [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)] [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

2013-12-02T23:59:59.000Z

8

A programmable quantum current standard from the Josephson and the quantum Hall effects  

SciTech Connect (OSTI)

We propose a way to realize a programmable quantum current standard (PQCS) from the Josephson voltage standard and the quantum Hall resistance standard (QHR) exploiting the multiple connection technique provided by the quantum Hall effect (QHE) and the exactness of the cryogenic current comparator. The PQCS could lead to breakthroughs in electrical metrology like the realization of a programmable quantum current source, a quantum ampere-meter, and a simplified closure of the quantum metrological triangle. Moreover, very accurate universality tests of the QHE could be performed by comparing PQCS based on different QHRs.

Poirier, W., E-mail: wilfrid.poirier@lne.fr; Lafont, F.; Djordjevic, S.; Schopfer, F.; Devoille, L. [Quantum metrology group, Laboratoire National de métrologie et d'Essais, 29 avenue Roger Hennequin, 78197 Trappes (France)

2014-01-28T23:59:59.000Z

9

Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells  

SciTech Connect (OSTI)

Spin Hall effect can be induced both by the extrinsic impurity scattering and by the intrinsic spin-orbit coupling in the electronic structure. The HgTe/CdTe quantum well has a quantum phase transition where the electronic structure changes from normal to inverted. We show that the intrinsic spin Hall effect of the conduction band vanishes on the normal side, while it is finite on the inverted side. This difference gives a direct mechanism to experimentally distinguish the intrinsic spin Hall effect from the extrinsic one.

Yang, Wen; Chang, Kai; /Beijing, Inst. Semiconductors; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-03-19T23:59:59.000Z

10

Quantum spin Hall effect in nanostructures based on cadmium fluoride  

SciTech Connect (OSTI)

Tunneling current-voltage (I-V) characteristics and temperature dependences of static magnetic susceptibility and specific heat of the CdB{sub x}F{sub 2-x}/p-CdF{sub 2}-QW/CdB{sub x}F{sub 2-x} planar sandwich structures formed on the surface of an n-CdF{sub 2} crystal have been studied in order to identify superconducting properties of the CdB{sub x}F{sub 2-x} {delta} barriers confining the p-type CdF{sub 2} ultranarrow quantum well. Comparative analysis of current-voltage (I-V) characteristics and conductance-voltage dependences (measured at the temperatures, respectively, below and above the critical temperature of superconducting transition) indicates that there is an interrelation between quantization of supercurrent and dimensional quantization of holes in the p-CdF{sub 2} ultranarrow quantum well. It is noteworthy that detection of the Josephson peak of current in each hole subband is accompanied by the appearance of the spectrum of the multiple Andreev reflection (MAR). A high degree of spin polarization of holes in the edge channels along the perimeter of the p-CdF{sub 2} ultranarrow quantum well appears as a result of MAR and makes it possible to identify the quantum spin Hall effect I-V characteristics; this effect becomes pronounced in the case of detection of nonzero conductance at the zero voltage applied to the vertical gate in the Hall geometry of the experiment. Within the energy range of superconducting gap, the I-V characteristics of the spin transistor and quantum spin Hall effect are controlled by the MAR spectrum appearing as the voltage applied to the vertical gate is varied. Beyond the range of the superconducting gap, the observed I-V characteristic of the quantum spin Hall effect is represented by a quantum conductance staircase with a height of the steps equal to e{sub 2}/h; this height is interrelated with the Aharonov-Casher oscillations of longitudinal and depends on the voltage applied to the vertical gate.

Bagraev, N. T., E-mail: Bagraev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Guimbitskaya, O. N. [St. Petersburg State Polytechnical University (Russian Federation); Klyachkin, L. E.; Koudryavtsev, A. A.; Malyarenko, A. M. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Romanov, V. V. [St. Petersburg State Polytechnical University (Russian Federation); Ryskin, A. I.; Shcheulin, A. S. [St. Petersburg State University of Information Technologies, Mechanics, and Optics (Russian Federation)

2010-10-15T23:59:59.000Z

11

The integer quantum hall effect revisited  

SciTech Connect (OSTI)

For T - L x L a finite subset of Z{sup 2}, let H{sub o} denote a Hamiltonian on T with periodic boundary conditions and finite range, finite strength intetactions and a unique ground state with a nonvanishing spectral gap. For S {element_of} T, let q{sub s} denote the charge at site s and assume that the total charge Q = {Sigma}{sub s {element_of} T} q{sub s} is conserved. Using the local charge operators q{sub s}, we introduce a boundary magnetic flux in the horizontal and vertical direction and allow the ground state to evolve quasiadiabatically around a square of size one magnetic flux, in flux space. At the end of the evolution we obtain a trivial Berry phase, which we compare, via a method reminiscent of Stokes Theorem. to the Berry phase obtained from an evolution around an exponentially small loop near the origin. As a result, we show, without any averaging assumption, that the Hall conductance is quantized in integer multiples of e{sup 2}/h up to exponentially small corrections of order e{sup -L/{zeta}}, where {zeta}, is a correlation length that depends only on the gap and the range and strength of the interactions.

Michalakis, Spyridon [Los Alamos National Laboratory; Hastings, Matthew [Q STATION, CALIFORNIA

2009-01-01T23:59:59.000Z

12

Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells  

SciTech Connect (OSTI)

We show that the quantum spin Hall (QSH) effect, a state of matter with topological properties distinct from those of conventional insulators, can be realized in mercury telluride-cadmium telluride semiconductor quantum wells. When the thickness of the quantum well is varied, the electronic state changes from a normal to an 'inverted' type at a critical thickness d{sub c}. We show that this transition is a topological quantum phase transition between a conventional insulating phase and a phase exhibiting the QSH effect with a single pair of helical edge states. We also discuss methods for experimental detection of the QSH effect.

Bernevig, A.

2010-03-02T23:59:59.000Z

13

The Quantum Spin Hall Effect: Theory and Experiment  

SciTech Connect (OSTI)

The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Recently, a new class of topological insulators has been proposed. These topological insulators have an insulating gap in the bulk, but have topologically protected edge states due to the time reversal symmetry. In two dimensions the helical edge states give rise to the quantum spin Hall (QSH) effect, in the absence of any external magnetic field. Here we review a recent theory which predicts that the QSH state can be realized in HgTe/CdTe semiconductor quantum wells. By varying the thickness of the quantum well, the band structure changes from a normal to an 'inverted' type at a critical thickness d{sub c}. We present an analytical solution of the helical edge states and explicitly demonstrate their topological stability. We also review the recent experimental observation of the QSH state in HgTe/(Hg,Cd)Te quantum wells. We review both the fabrication of the sample and the experimental setup. For thin quantum wells with well width d{sub QW} < 6.3 nm, the insulating regime shows the conventional behavior of vanishingly small conductance at low temperature. However, for thicker quantum wells (d{sub QW} > 6.3 nm), the nominally insulating regime shows a plateau of residual conductance close to 2e{sup 2}/h. The residual conductance is independent of the sample width, indicating that it is caused by edge states. Furthermore, the residual conductance is destroyed by a small external magnetic field. The quantum phase transition at the critical thickness, d{sub c} = 6.3 nm, is also independently determined from the occurrence of a magnetic field induced insulator to metal transition.

Konig, Markus; Buhmann, Hartmut; Molenkamp, Laurens W.; /Wurzburg U.; Hughes, Taylor L.; /Stanford U., Phys. Dept.; Liu, Chao-Xing; /Tsinghua U., Beijing /Stanford U., Phys. Dept.; Qi, Xiao-Liang; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-03-19T23:59:59.000Z

14

Topological superconductivity, topological confinement, and the vortex quantum Hall effect  

SciTech Connect (OSTI)

Topological matter is characterized by the presence of a topological BF term in its long-distance effective action. Topological defects due to the compactness of the U(1) gauge fields induce quantum phase transitions between topological insulators, topological superconductors, and topological confinement. In conventional superconductivity, because of spontaneous symmetry breaking, the photon acquires a mass due to the Anderson-Higgs mechanism. In this paper we derive the corresponding effective actions for the electromagnetic field in topological superconductors and topological confinement phases. In topological superconductors magnetic flux is confined and the photon acquires a topological mass through the BF mechanism: no symmetry breaking is involved, the ground state has topological order, and the transition is induced by quantum fluctuations. In topological confinement, instead, electric charge is linearly confined and the photon becomes a massive antisymmetric tensor via the Stueckelberg mechanism. Oblique confinement phases arise when the string condensate carries both magnetic and electric flux (dyonic strings). Such phases are characterized by a vortex quantum Hall effect potentially relevant for the dissipationless transport of information stored on vortices.

Diamantini, M. Cristina; Trugenberger, Carlo A. [INFN and Dipartimento di Fisica, University of Perugia, via A. Pascoli, I-06100 Perugia (Italy); SwissScientific, chemin Diodati 10, CH-1223 Cologny (Switzerland)

2011-09-01T23:59:59.000Z

15

Quantum spin Hall effect and topological insulators for light  

E-Print Network [OSTI]

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.

Bliokh, Konstantin Y

2015-01-01T23:59:59.000Z

16

Quantum Hall effect and Landau-level crossing of Dirac fermions in trilayer graphene  

E-Print Network [OSTI]

The physics of Dirac fermions in condensed-matter systems has received extraordinary attention following the discoveries of two new types of quantum Hall effect in single-layer and bilayer graphene1, 2, 3. The electronic ...

Taychatanapat, Thiti

17

Toward theory of quantum Hall effect in graphene  

E-Print Network [OSTI]

We analyze a gap equation for the propagator of Dirac quasiparticles and conclude that in graphene in a magnetic field, the order parameters connected with the quantum Hall ferromagnetism dynamics and those connected with the magnetic catalysis dynamics necessarily coexist (the latter have the form of Dirac masses and correspond to excitonic condensates). This feature of graphene could lead to important consequences, in particular, for the existence of gapless edge states. Solutions of the gap equation corresponding to recently experimentally discovered novel plateaus in graphene in strong magnetic fields are described.

E. V. Gorbar; V. P. Gusynin; V. A. Miransky

2007-10-18T23:59:59.000Z

18

The quantization of topology, from quantum Hall effect to quantum gravity  

E-Print Network [OSTI]

It is the goal of this article to extend the notion of quantization from the standard interpretation focused on non-commuting observables defined starting from classical analogues, to the topological equivalents defined in terms of coefficient groups in (co)homology. It is shown that the commutation relations between quantum observables become (non)compatibility relations between coefficient groups. The main result is the construction of a new, higher-level form of quantization, as seen from the perspective of the universal coefficient theorem. This idea brings us closer to a consistent quantization of gravity, allows for a systematic description of topology changing string interactions but also gives new, quantum-topological degrees of freedom in discussions involving quantum information. On the practical side, a possible connection to the fractional quantum Hall effect is explored.

Andrei T. Patrascu

2014-11-17T23:59:59.000Z

19

Split-quaternionic Hopf map, quantum Hall effect, and twistor theory  

SciTech Connect (OSTI)

Introducing a noncompact version of the Hopf map, we demonstrate remarkable close relations between quantum Hall effect and twistor theory. We first construct quantum Hall effect on a hyperboloid based on the noncompact 2nd Hopf map of split-quaternions. We analyze a hyperbolic one-particle mechanics, and explore many-body problem, where a many-body ground state wave function and membrane-like excitations are derived explicitly. In the lowest Landau level, the symmetry is enhanced from SO(3,2) to the SU(2,2) conformal symmetry. We point out that the quantum Hall effect naturally realizes the philosophy of twistor theory. In particular, emergence mechanism of fuzzy space-time is discussed somehow in detail.

Hasebe, Kazuki [Department of General Education, Kagawa National College of Technology, Takuma-cho, Mitoyo-city, Kagawa 769-1192 (Japan)

2010-02-15T23:59:59.000Z

20

Title: Electron-Hole Asymmetric Integer and Fractional Quantum Hall Effect in Bilayer Graphene  

E-Print Network [OSTI]

Title: Electron-Hole Asymmetric Integer and Fractional Quantum Hall Effect in Bilayer Graphene graphene is predicted to pro- duce novel and tunable FQH ground states. Here we present local electronic compressibility measurements of the FQH effect in the lowest Landau level of bilayer graphene. We observe

Yacoby, Amir

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

A novel method of including Landau level mixing in numerical studies of the quantum Hall effect  

SciTech Connect (OSTI)

Landau level mixing should influence the quantum Hall effect for all except the strongest applied magnetic fields. We propose a simple method for examining the effects of Landau level mixing by incorporating multiple Landau levels into the Haldane pseudopotentials through exact numerical diagonalization. Some of the resulting pseudopotentials for the lowest and first excited Landau levels will be presented.

Wooten, Rachel; Quinn, John; Macek, Joseph [Department of Physics and Astronomy, University of Tennessee, Knoxville TN 37996-1501 (United States)

2013-12-04T23:59:59.000Z

22

Engineering the quantum anomalous Hall effect in graphene with uniaxial strains  

SciTech Connect (OSTI)

We theoretically investigate the manipulation of the quantum anomalous Hall effect (QAHE) in graphene by means of the uniaxial strain. The values of Chern number and Hall conductance demonstrate that the strained graphene in presence of Rashba spin-orbit coupling and exchange field, for vanishing intrinsic spin-orbit coupling, possesses non-trivial topological phase, which is robust against the direction and modulus of the strain. Besides, we also find that the interplay between Rashba and intrinsic spin-orbit couplings results in a topological phase transition in the strained graphene. Remarkably, as the strain strength is increased beyond approximately 7%, the critical parameters of the exchange field for triggering the quantum anomalous Hall phase transition show distinct behaviors—decrease (increase) for strains along zigzag (armchair) direction. Our findings open up a new platform for manipulation of the QAHE by an experimentally accessible strain deformation of the graphene structure, with promising application on novel quantum electronic devices with high efficiency.

Diniz, G. S., E-mail: ginetom@gmail.com; Guassi, M. R. [Institute of Physics, University of Brasília, 70919-970 Brasília-DF (Brazil); Qu, F. [Institute of Physics, University of Brasília, 70919-970 Brasília-DF (Brazil); Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)

2013-12-28T23:59:59.000Z

23

Non-Commutative Geometry in Higher Dimensional Quantum Hall Effect as A-Class Topological Insulator  

E-Print Network [OSTI]

We clarify relations between the higher dimensional quantum Hall effect and A-class topological insulator. In particular, we elucidate physical implications of the higher dimensional non-commutative geometry in the context of A-class topological insulator. This presentation is based on arXiv:1403.5066.

Kazuki Hasebe

2014-08-04T23:59:59.000Z

24

Electrical Readout of the Local Nuclear Polarization in the Quantum Hall Effect: A Hyperfine Battery  

E-Print Network [OSTI]

Electrical Readout of the Local Nuclear Polarization in the Quantum Hall Effect: A Hyperfine Battery A. Wu¨rtz,1,* T. Mu¨ller,1 A. Lorke,1, D. Reuter,2 and A. D. Wieck2 1 Laboratorium fu¨r Festko which utilizes separately contacted edge states to establish a local nuclear spin polarization

Lorke, Axel

25

Half integer quantum Hall effect in high mobility single layer epitaxial graphene  

E-Print Network [OSTI]

Half integer quantum Hall effect in high mobility single layer epitaxial graphene Xiaosong Wu,1 of is demonstrated here on a single graphene layer grown on the C-face of 4H silicon carbide. The mobility is 20 000. This is comparable to the best exfoliated graphene flakes on SiO2 and an order of magnitude larger than Si

26

Excitonic gap, phase transition, and quantum Hall effect in graphene  

E-Print Network [OSTI]

We suggest that physics underlying the recently observed removal of sublattice and spin degeneracies in graphene in a strong magnetic field describes a phase transition connected with the generation of an excitonic gap. The experimental form of the Hall conductivity is reproduced and the main characteristics of the dynamics are described. Predictions of the behavior of the gap as a function of temperature and a gate voltage are made.

V. P. Gusynin; V. A. Miransky; S. G. Sharapov; I. A. Shovkovy

2006-11-23T23:59:59.000Z

27

Interface engineering of quantum Hall effects in digital transition metal oxide heterostructures  

SciTech Connect (OSTI)

Topological insulators (TIs) are characterized by a non-trivial band topology driven by the spin-orbit coupling. To fully explore the fundamental science and application of TIs, material realization is indispensable. Here we predict, based on tight-binding modeling and first-principles calculations, that bilayers of perovskite-type transition-metal oxides grown along the [111] crystallographic axis are potential candidates for two-dimensional TIs. The topological band structure of these materials can be fine-tuned by changing dopant ions, substrates and external gate voltages. We predict that LaAuO$_3$ bilayers have a topologically non-trivial energy gap of about 0.15~eV, which is sufficiently large to realize the quantum spin Hall effect at room temperature. Intriguing phenomena, such as fractional quantum Hall effect, associated with the nearly flat topologically non-trivial bands found in $e_g$ systems are also discussed.

Xiao, Di [ORNL; Zhu, Wenguang [University of Tennessee, Knoxville (UTK); Ran, Ying [Boston College, Chestnut Hill; Nagaosa, Naoto [University of Tokyo, Tokyo, Japan; Okamoto, Satoshi [ORNL

2011-01-01T23:59:59.000Z

28

Coulomb interaction and magnetic catalysis in the quantum Hall effect in graphene  

E-Print Network [OSTI]

The dynamics of symmetry breaking responsible for lifting the degeneracy of the Landau levels in the integer quantum Hall effect in graphene is studied in a low-energy model with the Coulomb interaction. The gap equation for Dirac quasiparticles is analyzed for both the lowest and higher Landau levels, taking into account the Landau levels mixing. It is shown that the characteristic feature of the long-range Coulomb interaction is the decrease of the gap parameters with increasing the Landau level index $n$ ("running" gaps). The renormalization (running) of the Fermi velocity as a function of $n$ is also studied. The solutions of the gap equation reproduce correctly the experimentally observed integer quantum Hall plateaus in graphene in strong magnetic fields.

E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy

2012-02-01T23:59:59.000Z

29

Field effect in the quantum Hall regime of a high mobility graphene wire  

SciTech Connect (OSTI)

In graphene-based electronic devices like in transistors, the field effect applied thanks to a gate electrode allows tuning the charge density in the graphene layer and passing continuously from the electron to the hole doped regime across the Dirac point. Homogeneous doping is crucial to understand electrical measurements and for the operation of future graphene-based electronic devices. However, recently theoretical and experimental studies highlighted the role of the electrostatic edge due to fringing electrostatic field lines at the graphene edges [P. Silvestrov and K. Efetov, Phys. Rev. B 77, 155436 (2008); F. T. Vasko and I. V. Zozoulenko, Appl. Phys. Lett. 97, 092115 (2010)]. This effect originates from the particular geometric design of the samples. A direct consequence is a charge accumulation at the graphene edges giving a value for the density, which deviates from the simple picture of a plate capacitor and also varies along the width of the graphene sample. Entering the quantum Hall regime would, in principle, allow probing this accumulation thanks to the extreme sensitivity of this quantum effect to charge density and the charge distribution. Moreover, the presence of an additional and counter-propagating edge channel has been predicted [P. Silvestrov and K. Efetov, Phys. Rev. B 77, 155436 (2008)] giving a fundamental aspect to this technological issue. In this article, we investigate this effect by tuning a high mobility graphene wire into the quantum Hall regime in which charge carriers probe the electrostatic potential at high magnetic field close to the edges. We observe a slight deviation to the linear shift of the quantum Hall plateaus with magnetic field and we study its evolution for different filling factors, which correspond to different probed regions in real space. We discuss the possible origins of this effect including an increase of the charge density towards the edges.

Barraud, C., E-mail: cbarraud@phys.ethz.ch, E-mail: clement.barraud@univ-paris-diderot.fr; Choi, T.; Ihn, T.; Ensslin, K. [Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich (Switzerland); Butti, P.; Shorubalko, I. [Swiss Federal Laboratories of Materials Science and Technologies, EMPA Elect. Metrol. Reliabil. Lab., CH-8600 Dübendorf (Switzerland); Taniguchi, T.; Watanabe, K. [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

2014-08-21T23:59:59.000Z

30

Higher Dimensional Quantum Hall Effect as A-Class Topological Insulator  

E-Print Network [OSTI]

We perform a detail study of higher dimensional quantum Hall effects and A-class topological insulators with emphasis on their relations to non-commutative geometry. There are two different formulations of non-commutative geometry for higher dimensional fuzzy spheres; the ordinary commutator formulation and quantum Nambu bracket formulation. Corresponding to these formulations, we introduce two kinds of monopole gauge fields; non-abelian gauge field and antisymmetric tensor gauge field, which respectively realize the non-commutative geometry of fuzzy sphere in the lowest Landau level. We establish connection between the two types of monopole gauge fields through Chern-Simons term, and derive explicit form of tensor monopole gauge fields with higher string-like singularity. The connection between two types of monopole is applied to generalize the concept of flux attachment in quantum Hall effect to A-class topological insulator. We propose tensor type Chern-Simons theory as the effective field theory for membranes in A-class topological insulators. Membranes turn out to be fractionally charged objects and the phase entanglement mediated by tensor gauge field transforms the membrane statistics to be anyonic. The index theorem supports the dimensional hierarchy of A-class topological insulator. Analogies to D-brane physics of string theory are discussed too.

Kazuki Hasebe

2014-08-02T23:59:59.000Z

31

Quantum anomalous Hall effect with cold atoms trapped in a square lattice  

E-Print Network [OSTI]

in the recently discovered graphene system since the required staggered magnetic flux in the model is extremely hard to achieve. A recent proposal predicts the QAHE in the Hg1?xMnxTe quantum wells [6] by doping Mn atoms in the quantum spin Hall system...

Liu, Xiong-Jun; Liu, Xin; Wu, Congjun; Sinova, Jairo

2010-01-01T23:59:59.000Z

32

Edge states in graphene quantum dots: Fractional quantum Hall effect analogies and differences at zero magnetic field  

E-Print Network [OSTI]

We investigate the way that the degenerate manifold of midgap edge states in quasicircular graphene quantum dots with zig-zag boundaries supports, under free-magnetic-field conditions, strongly correlated many-body behavior analogous to the fractional quantum Hall effect (FQHE), familiar from the case of semiconductor heterostructures in high magnetic fields. Systematic exact-diagonalization (EXD) numerical studies are presented for the first time for 5 graphene REMs exhibit in all instances a single (0,N) polygonal-ring molecular (crystalline) structure, with all the electrons localized on the edge. Disruptions in the zig-zag boundary condition along the circular edge act effectively as impurities that pin the electron molecule, yielding single-particle densities with broken rotational symmetry that portray directly the azimuthal localization of the edge electrons.

Igor Romanovsky; Constantine Yannouleas; Uzi Landman

2009-01-15T23:59:59.000Z

33

Dynamics in the quantum Hall effect and the phase diagram of graphene  

E-Print Network [OSTI]

The dynamics responsible for lifting the degeneracy of the Landau levels in the quantum Hall (QH) effect in graphene is studied by utilizing a low-energy effective model with a contact interaction. A detailed analysis of the solutions of the gap equation for Dirac quasiparticles is performed at both zero and nonzero temperatures. The characteristic feature of the solutions is that the order parameters connected with the QH ferromagnetism and magnetic catalysis scenarios necessarily coexist. The solutions reproduce correctly the experimentally observed novel QH plateaus in graphene in strong magnetic fields. The phase diagram of this system in the plane of temperature and electron chemical potential is analyzed. The phase transitions corresponding to the transitions between different QH plateaus in graphene are described.

E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy

2008-08-28T23:59:59.000Z

34

M-Theory Brane as Giant Graviton and the Fractional Quantum Hall Effect  

E-Print Network [OSTI]

A small number of M-theory branes as giant gravitons in the M-theory sector of LLM geometry is studied as a probe. The abelian way shows that the low energy effective action for M-theory brane is exactly the 2d electron subject to a vertical magnetic field. We also briefly discuss the microscopic description of M2-brane giant graviton in this geometry, in the language of a combination of D0-branes as fuzzy 2-spheres. Then we go to the well-established Noncommutative Chern-Simons theory description. After quantization, well behaved Fractional Quantum Hall Effect is demonstrated. This goes beyond the original LLM description and should be some indication of novel geometry.

Ran Huo

2006-07-30T23:59:59.000Z

35

Superlattices and Microstructures, Vol. 22, No. 4, 1997 Current distribution in the integer quantum Hall effect: The role of  

E-Print Network [OSTI]

. Experimental setup The two-dimensional electron gas sample was fabricated from GaAs/AlGaAs heterostructures, Tel-Aviv University, Tel-Aviv 69978, Israel Hadas Shtrikman Department of Condensed Matter currents in a two-dimensional electron gas under the conditions of the integer quantum Hall effect (IQHE

Palevski, Alexander

36

Quantum Hall Effect In Bilayer Systems And The Noncommutative Plane: A Toy Model Approach  

E-Print Network [OSTI]

We have presented a quantum mechanical toy model for the study of Coulomb interactions in Quantum Hall (QH) system. Inclusion of Coulomb interaction is essential for the study of {\\it{bilayer}} QH system and our model can simulate it, in the compound state, in a perturbative framework. We also show that in the noncommutative plane, the Coulomb interaction is modified at a higher order in the noncommutativity parameter $\\theta$, and only if $\\theta$ varies from layer to layer in the QH system.

B. Basu; Subir Ghosh

2005-07-19T23:59:59.000Z

37

Fractional Quantum Hall States in Graphene  

E-Print Network [OSTI]

We quantum mechanically analyze the fractional quantum Hall effect in graphene. This will be done by building the corresponding states in terms of a potential governing the interactions and discussing other issues. More precisely, we consider a system of particles in the presence of an external magnetic field and take into account of a specific interaction that captures the basic features of the Laughlin series \

Ahmed Jellal; Bellati Malika

2008-05-15T23:59:59.000Z

38

Engineering of Quantum Hall Effect from Type IIA String Theory on The K3 Surface  

E-Print Network [OSTI]

Using D-brane configurations on the K3 surface, we give six dimensional type IIA stringy realizations of the Quantum Hall Effect (QHE) in 1+2 dimensions. Based on the vertical and horizontal lines of the K3 Hodge diamond, we engineer two different stringy realizations. The vertical line presents a realization in terms of D2 and D6-branes wrapping the K3 surface. The horizontal one is associated with hierarchical stringy descriptions obtained from a quiver gauge theory living on a stack of D4-branes wrapping intersecting 2-spheres embedded in the K3 surface with deformed singularities. These geometries are classified by three kinds of the Kac-Moody algebras: ordinary, i.e finite dimensional, affine and indefinite. We find that no stringy QHE in 1+2 dimensions can occur in the quiver gauge theory living on intersecting 2-spheres arranged as affine Dynkin diagrams. Stringy realizations of QHE can be done only for the finite and indefinite geometries. In particular, the finite Lie algebras give models with fractional filling fractions, while the indefinite ones classify models with negative filling fractions which can be associated with the physics of holes in the graphene.

Adil Belhaj; Antonio Segui

2010-07-02T23:59:59.000Z

39

Topological Spin Texture in a Quantum Anomalous Hall Insulator  

E-Print Network [OSTI]

The quantum anomalous Hall (QAH) effect has been recently discovered in an experiment using a thin-film topological insulator with ferromagnetic ordering and strong spin-orbit coupling. Here we investigate the spin degree ...

Wu, Jiansheng

40

Topology-induced phase transitions in quantum spin Hall lattices  

SciTech Connect (OSTI)

Physical phenomena driven by topological properties, such as the quantum Hall effect, have the appealing feature that they are robust with respect to external perturbations. Lately, a new class of materials has emerged that manifests topological properties at room temperature and without the need of external magnetic fields. These topological insulators are band insulators with large spin-orbit interactions and exhibit the quantum spin-Hall (QSH) effect. Here we investigate the transition between QSH and normal insulating phases under topological deformations of a two-dimensional lattice. We demonstrate that the QSH phase present in the honeycomb lattice loses its robustness as the occupancy of extra lattice sites is allowed. Furthermore, we propose a method for verifying our predictions with fermionic cold atoms in optical lattices. In this context, the spin-orbit interaction is engineered via an appropriate synthetic gauge field.

Bercioux, D.; Goldman, N.; Urban, D. F. [Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universitaet, D-79104 Freiburg, Germany and Physikalisches Institut, Albert-Ludwigs-Universitaet, D-79104 Freiburg (Germany); Center for Nonlinear Phenomena and Complex Systems, UniversitAlbert-Ludwigs-Universitaet Libre de Bruxelles (U.L.B.), Code Postal 231, Campus Plaine, B-1050 Brussels (Belgium); Physikalisches Institut, Albert-Ludwigs-Universitaet, D-79104 Freiburg (Germany)

2011-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Contactless measurement of alternating current conductance in quantum Hall structures  

SciTech Connect (OSTI)

We report a procedure to determine the frequency-dependent conductance of quantum Hall structures in a broad frequency domain. The procedure is based on the combination of two known probeless methods—acoustic spectroscopy and microwave spectroscopy. By using the acoustic spectroscopy, we study the low-frequency attenuation and phase shift of a surface acoustic wave in a piezoelectric crystal in the vicinity of the electron (hole) layer. The electronic contribution is resolved using its dependence on a transverse magnetic field. At high frequencies, we study the attenuation of an electromagnetic wave in a coplanar waveguide. To quantitatively calibrate these data, we use the fact that in the quantum-Hall-effect regime the conductance at the maxima of its magnetic field dependence is determined by extended states. Therefore, it should be frequency independent in a broad frequency domain. The procedure is verified by studies of a well-characterized p-SiGe/Ge/SiGe heterostructure.

Drichko, I. L.; Diakonov, A. M.; Malysh, V. A.; Smirnov, I. Yu.; Ilyinskaya, N. D.; Usikova, A. A. [A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Galperin, Y. M. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo (Norway); A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Kummer, M.; Känel, H. von [Laboratorium für Festkörperphysik ETH Zürich, CH-8093 Zürich (Switzerland)

2014-10-21T23:59:59.000Z

42

Josephson inplane and tunneling currents in bilayer quantum Hall system  

SciTech Connect (OSTI)

A Bose-Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (–e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ? = 1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless in tunneling experiments with various geometries.

Ezawa, Z. F. [Nishina Center, RIKEN, Saitama 351-0198 (Japan); Tsitsishvili, G. [Georgia Department of Physics, Tbilisi State University, Tbilisi 0179 (Georgia); Sawada, A. [Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8501 (Japan)

2013-12-04T23:59:59.000Z

43

Spin Hall Effect For Anyons  

E-Print Network [OSTI]

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.

S. Dhar; B. Basu; Subir Ghosh

2007-06-27T23:59:59.000Z

44

Review of Scientific instruments InAs/Al0.2Ga0.8Sb Quantum Well Hall Sensors  

E-Print Network [OSTI]

1 Review of Scientific instruments InAs/Al0.2Ga0.8Sb Quantum Well Hall Sensors with improved Boeck, G. Borghs IMEC, Kapeldreef 75, B-3001 Leuven, Belgium Cross-shaped Hall sensors with high. Introduction Hall effect devices are by far the most widely used magnetic sensors today. Their future mainly

Moshchalkov, Victor V.

45

Edge and bulk components of lowest-Landau-level orbitals, correlated fractional quantum Hall effect incompressible states, and insulating behavior in finite graphene samples  

E-Print Network [OSTI]

Many-body calculations of the total energy of interacting Dirac electrons in finite graphene samples exhibit joint occurrence of cusps at angular momenta corresponding to fractional fillings characteristic of formation of incompressible (gapped) correlated states (nu=1/3 in particular) and opening of an insulating energy gap (that increases with the magnetic field) at the Dirac point, in correspondence with experiments. Single-particle basis functions obeying the zigzag boundary condition at the sample edge are employed in exact diagonalization of the interelectron Coulomb interaction, showing, at all sizes, mixed equal-weight bulk and edge components. The consequent depletion of the bulk electron density attenuates the fractional-quantum-Hall-effect excitation energies and the edge charge accumulation results in a gap in the many-body spectrum.

Constantine Yannouleas; Igor Romanovsky; Uzi Landman

2010-09-13T23:59:59.000Z

46

High Field Quantum Spin Hall State in Graphene  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

quantum spin Hall (QSH) state-the paradigmatic two dimensional SPT phase-in monolayer graphene. In a QSH state, electrons with opposite spin polarization carry current in opposite...

47

Quantum Hall conductance of two-terminal graphene devices  

E-Print Network [OSTI]

Measurement and theory of the two-terminal conductance of monolayer and bilayer graphene in the quantum Hall regime are compared. We examine features of conductance as a function of gate voltage that allow monolayer, ...

Williams, J. R.

48

Hall-effect arc protector  

DOE Patents [OSTI]

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored.

Rankin, Richard A. (Ammon, ID); Kotter, Dale K. (Shelley, ID)

1997-01-01T23:59:59.000Z

49

Hall-effect arc protector  

DOE Patents [OSTI]

The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

Rankin, R.A.; Kotter, D.K.

1997-05-13T23:59:59.000Z

50

Probing spin entanglement by gate-voltage-controlled interference of current correlation in quantum spin Hall insulators  

E-Print Network [OSTI]

We propose an entanglement detector composed of two quantum spin Hall insulators and a side gate deposited on one of the edge channels. For an ac gate voltage, the differential noise contributed from the entangled electron pairs exhibits the nontrivial step structures, from which the spin entanglement concurrence can be easily obtained. The possible spin dephasing effects in the quantum spin Hall insulators are also included.

Wei Chen; Z. D. Wang; R. Shen; D. Y. Xing

2014-05-21T23:59:59.000Z

51

Quantum Hall Charge Sensor for Single-Donor Nuclear Spin Detection in Silicon  

E-Print Network [OSTI]

We propose a novel optical and electrical hybrid scheme for the measurement of nuclear spin qubits in silicon. By combining the environmental insensitivity of the integer quantum Hall effect with the optically distinguishable hyperfine states of phosphorus impurities in silicon, our system can simultaneously offer nuclear spin measurement and robustness against environmental defects. 31P donor spins in isotopically purified 28Si are often discussed as very promising quantum memory qubits due to their extremely long decoherence times, and our proposed device offers an effective implementation for such a quantum memory system.

Sleiter, D; Nozawa, K; Ladd, T D; Thewalt, M L W; Yamamoto, Y

2010-01-01T23:59:59.000Z

52

Quantum Hall Charge Sensor for Single-Donor Nuclear Spin Detection in Silicon  

E-Print Network [OSTI]

We propose a novel optical and electrical hybrid scheme for the measurement of nuclear spin qubits in silicon. By combining the environmental insensitivity of the integer quantum Hall effect with the optically distinguishable hyperfine states of phosphorus impurities in silicon, our system can simultaneously offer nuclear spin measurement and robustness against environmental defects. 31P donor spins in isotopically purified 28Si are often discussed as very promising quantum memory qubits due to their extremely long decoherence times, and our proposed device offers an effective implementation for such a quantum memory system.

D. Sleiter; N. Y. Kim; K. Nozawa; T. D. Ladd; M. L. W. Thewalt; Y. Yamamoto

2010-05-12T23:59:59.000Z

53

Negative nonlocal resistance in mesoscopic gold Hall bars : absence of giant spin Hall effect.  

SciTech Connect (OSTI)

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.

Mihajlovic, G.; Pearson, J. E.; Garcia, M. A.; Bader, S. D.; Hoffmann, A.; Univ. Complutense de Madrid

2009-01-01T23:59:59.000Z

54

Controllable spin entanglement production in a quantum spin Hall ring  

E-Print Network [OSTI]

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.

Anders Ström; Henrik Johannesson; Patrik Recher

2015-03-13T23:59:59.000Z

55

Evidence for spontaneous interlayer phase coherence in a bilayer quantum Hall exciton condensate  

E-Print Network [OSTI]

double layer 2D electron gas sample. There are several equivalent ways to view the strongly correlatedEvidence for spontaneous interlayer phase coherence in a bilayer quantum Hall exciton condensate J of the excitonic Bose condensate which describes this remarkable quantum Hall state. q 2003 Published by Elsevier

Eisenstein, Jim

56

Renormalization group approach to energy level statistics at the integer quantum Hall transition  

E-Print Network [OSTI]

Renormalization group approach to energy level statistics at the integer quantum Hall transition) approach to study the energy level statistics at the integer quantum Hall (QH) transition. Within the RG, at the transition, the nearest neighbor energy level spacing distribution (LSD) exhibits well-pronounced level

Chemnitz, Technische Universität

57

Photonic spin Hall effect in topological insulators  

E-Print Network [OSTI]

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.

Zhou, Xinxing; Ling, Xiaohui; Chen, Shizhen; Luo, Hailu; Wen, Shuangchun

2013-01-01T23:59:59.000Z

58

Hall effect at a tunable metal-insulator transition  

E-Print Network [OSTI]

Using a rotating magnetic field, the Hall effect in three-dimensional amorphous GdxSi1-x has been measured in the critical regime of the metal-insulator transition for a constant total magnetic field. The Hall coefficient R-0 is negative, indicating...

Teizer, Winfried; Hellman, F.; Dynes, RC.

2003-01-01T23:59:59.000Z

59

M5-brane defect and quantum Hall effect in AdS{sub 4}xN(1,1)/N=3 superconformal field theory  

SciTech Connect (OSTI)

We study the d=11 gravity dual AdS{sub 4}xN(1,1) of the d=3 N=3 flavored Chern-Simons-matter theory. In the dual gravity side, we analyze the M5-brane filling AdS{sub 3} inside AdS{sub 4} and derive the quantized Hall conductivity of the dual gauge theory. In the gauge theory side, this M5-brane intersects the gauge theory at the codimension-one defect.

Fujita, Mitsutoshi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2011-05-15T23:59:59.000Z

60

Mesoscopic spin Hall effect in multiprobe ballistic spin-orbit-coupled semiconductor bridges Branislav K. Nikoli, Liviu P. Zrbo, and Satofumi Souma  

E-Print Network [OSTI]

Mesoscopic spin Hall effect in multiprobe ballistic spin-orbit-coupled semiconductor bridges attached to ballistic quantum-coherent two-dimensional electron gas 2DEG in semiconductor heterostructure current are signatures of the spin Hall effect in four-probe Rashba spin-split semiconductor

Nikolic, Branislav K.

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Experimental Observation of the Inverse Spin Hall Effect at Room Temperature  

SciTech Connect (OSTI)

We observe the inverse spin Hall effect in a two-dimensional electron gas confined in Al-GaAs/InGaAs quantum wells. Specifically, they find that an inhomogeneous spin density induced by the optical injection gives rise to an electric current transverse to both the spin polarization and its gradient. The spin Hall conductivity can be inferred from such a measurement through the Einstein relation and the onsager relation, and is found to have the order of magnitude of 0.5(e{sup 2}/h). The observation is made at the room temperature and in samples with macroscopic sizes, suggesting that the inverse spin Hall effects is a robust macroscopic transport phenomenon.

Liu, Baoli; Shi, Junren; Wang, Wenxin; Zhao, Hongming; Li, Dafang; /Beijing, Inst. Phys.; Zhang, Shoucheng; /Stanford U., Phys. Dept.; Xue, Qikun; Chen, Dongmin; /Beijing, Inst. Phys.

2010-03-16T23:59:59.000Z

62

Kinetic Effects In Hall Thruster Discharge  

E-Print Network [OSTI]

of a capacitive discharge. 4 capacitive discharge. For more info: V. Godyak, IEEE TPS 34, 755 (2006). #12 th twall interactions in Hall thrusters Large electron temperature andE JH~1cm secondary electron emission result in large particle and wall losses to the wall E , Jz z Br H~1cm 120 eV High SEE BN channel

Kaganovich, Igor

63

Coulomb Oscillations in Antidots in the Integer and Fractional Quantum Hall Regimes  

E-Print Network [OSTI]

We report measurements of resistance oscillations in micron-scale antidots in both the integer and fractional quantum Hall regimes. In the integer regime, we conclude that oscillations are of the Coulomb type from the scaling of magnetic field period with the number of edges bound to the antidot. Based on both gate-voltage and field periods, we find at filling factor {\

A. Kou; C. M. Marcus; L. N. Pfeiffer; K. W. West

2012-01-08T23:59:59.000Z

64

Resistance Fluctuations and AharonovBohm-Type Oscillations in Antidot Arrays in the Quantum Hall Regime  

E-Print Network [OSTI]

Resistance Fluctuations and Aharonov­Bohm-Type Oscillations in Antidot Arrays in the Quantum Hall fluctuations (RFs) and the other is the Aharonov­Bohm (AB)-type oscillations. Their dependences on the magnetic field and the gate voltage are quite distinct. While the aperiodic RFs are attributed to the complex

Iye, Yasuhiro

65

Coulomb Oscillations in Antidots in the Integer and Fractional Quantum Hall Regimes  

E-Print Network [OSTI]

We report measurements of resistance oscillations in micron-scale antidots in both the integer and fractional quantum Hall regimes. In the integer regime, we conclude that oscillations are of the Coulomb type from the scaling of magnetic field period with the number of edges bound to the antidot. Based on both gate-voltage and field periods, we find at filling factor {\

Kou, A; Pfeiffer, L N; West, K W

2012-01-01T23:59:59.000Z

66

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"  

E-Print Network [OSTI]

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene" Impartido por physics is to realize a topological insulating phase in 2-dimensional Graphene [1,2]. Recent theoretical studies have shown that dissipation-less edge conducting channels emerge in graphene nanoribbons when

Escolano, Francisco

67

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"  

E-Print Network [OSTI]

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene" Impartit per: David physics is to realize a topological insulating phase in 2-dimensional Graphene [1,2]. Recent theoretical studies have shown that dissipation-less edge conducting channels emerge in graphene nanoribbons when

Escolano, Francisco

68

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"  

E-Print Network [OSTI]

"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene" By: David Soriano is to realize a topological insulating phase in 2-dimensional Graphene [1,2]. Recent theoretical studies have shown that dissipation-less edge conducting channels emerge in graphene nanoribbons when doped with soft

Escolano, Francisco

69

Quantum Hall phases and plasma analogy in rotating trapped Bose gases  

E-Print Network [OSTI]

. In this regime, the atoms all condense in the same one-particle state and the gas forms a Bose. Our analysis is based on the interpretation of the densities of quantum Hall trial states as Gibbs-Einstein condensate (BEC). Th

70

Electric control of the spin Hall effect by intervalley transitions  

E-Print Network [OSTI]

tunability of the creation/detection efficiency of spin currents, with clear relevance for future memory and logic devices. 8 I. METHODS A. Measurement The sample structure used in this study is Si-doped (the initial electron density n0e=1.01×1016 cm?3) n... ., & Jungwirth T. Spin-injection Hall effect in a planar photovoltaic cell Nature Phys. 5, 675 (2009). 24 Wunderlich, J., Park, B. G., Irvine, A. C., Zarbo, L. P. , Rozkotova, E., Nemec, P., Novak, V., Sinova, J., & Jungwirth, T. Spin Hall effect transistor...

Okamoto, N.; Kurebayashi, H.; Trypiniotis, T.; Farrer, I.; Ritchie, D. A.; Saitoh, E.; Sinova, J.; Mašek, J.; Jungwirth, T.; Barnes, C. H. W.

2014-08-10T23:59:59.000Z

71

Theory of the Anomalous Hall Effect in the Insulating Regime  

E-Print Network [OSTI]

, the AHE was revived in recent years by generating many new understandings and phenomena, e.g. spin-Hall effect, topological insulators. The phase diagram of the AHE was shown recently to exhibit three distinct regions: a skew scattering region in the high...

Liu, Xiongjun

2012-10-19T23:59:59.000Z

72

Mass Flow Control in a Magnesium Hall-effect Thruster Mark A. Hopkins*  

E-Print Network [OSTI]

Mass Flow Control in a Magnesium Hall-effect Thruster Mark A. Hopkins* , Jason M. Makela , Robert L reported in this paper examined methods of operating a Hall-effect thruster on solid magnesium propellant University began performing experiments using magnesium and zinc as propellants for a Hall-effect thruster1

King, Lyon B.

73

Effects of Enhanced Eathode Electron Emission on Hall Thruster Operation  

SciTech Connect (OSTI)

Interesting discharge phenomena are observed that have to do with the interaction between the magnetized Hall thruster plasma and the neutralizing cathode. The steadystate parameters of a highly ionized thruster discharge are strongly influenced by the electron supply from the cathode. The enhancement of the cathode electron emission above its self-sustained level affects the discharge current and leads to a dramatic reduction of the plasma divergence and a suppression of large amplitude, low frequency discharge current oscillations usually related to an ionization instability. These effects correlate strongly with the reduction of the voltage drop in the region with the fringing magnetic field between the thruster channel and the cathode. The measured changes of the plasma properties suggest that the electron emission affects the electron cross-field transport in the thruster discharge. These trends are generalized for Hall thrusters of various configurations.

Y. Raitses, A. Smirnov and N. J. Fisch

2009-04-24T23:59:59.000Z

74

Hall effect in a strong magnetic field: Direct comparisons of compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic equations  

SciTech Connect (OSTI)

In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.

Martin, L. N.; Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina) and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Gomez, D. O. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina) and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

2010-11-15T23:59:59.000Z

75

Fractionalization in Josephson junction arrays hinged by quantum spin Hall edges  

SciTech Connect (OSTI)

We study a superconductor-ferromagnet-superconductor (SC-FM-SC) Josephson array deposited on top of a two-dimensional quantum spin Hall insulator. The Majorana bound state at the interface between SC and FM leads to charge-e tunneling between neighboring superconductor islands, in addition to the usual charge-2e Cooper pair tunneling. Moreover, because Majorana fermions encode the information of charge number parity, an exact Z{sub 2} gauge structure naturally emerges and leads to many new phases, including a deconfined phase where electrons fractionalize into charge-e bosons and topological defects. A deconfined SC-insulator transition has also been found.

Xu Cenke; Fu Liang [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2010-04-01T23:59:59.000Z

76

Invited Article: An integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument  

SciTech Connect (OSTI)

We report on the development of the first integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, covering an ultra wide spectral range from 3 cm{sup ?1} to 7000 cm{sup ?1} (0.1–210 THz or 0.4–870 meV). The instrument comprises four sub-systems, where the magneto-cryostat-transfer sub-system enables the usage of the magneto-cryostat sub-system with the mid-infrared ellipsometer sub-system, and the far-infrared/terahertz ellipsometer sub-system. Both ellipsometer sub-systems can be used as variable angle-of-incidence spectroscopic ellipsometers in reflection or transmission mode, and are equipped with multiple light sources and detectors. The ellipsometer sub-systems are operated in polarizer-sample-rotating-analyzer configuration granting access to the upper left 3 × 3 block of the normalized 4 × 4 Mueller matrix. The closed cycle magneto-cryostat sub-system provides sample temperatures between room temperature and 1.4 K and magnetic fields up to 8 T, enabling the detection of transverse and longitudinal magnetic field-induced birefringence. We discuss theoretical background and practical realization of the integrated mid-infrared, far-infrared, and terahertz optical Hall effect instrument, as well as acquisition of optical Hall effect data and the corresponding model analysis procedures. Exemplarily, epitaxial graphene grown on 6H-SiC, a tellurium doped bulk GaAs sample and an AlGaN/GaN high electron mobility transistor structure are investigated. The selected experimental datasets display the full spectral, magnetic field and temperature range of the instrument and demonstrate data analysis strategies. Effects from free charge carriers in two dimensional confinement and in a volume material, as well as quantum mechanical effects (inter-Landau-level transitions) are observed and discussed exemplarily.

Kühne, P., E-mail: kuehne@huskers.unl.edu; Schubert, M., E-mail: schubert@engr.unl.edu; Hofmann, T., E-mail: thofmann@engr.unl.edu [Department of Electrical Engineering and Center for Nanohybrid Functional Materials, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Herzinger, C. M., E-mail: cherzinger@jawoollam.com; Woollam, J. A., E-mail: jwoollam@jawoollam.com [J. A. Woollam Co., Inc., 645 M Street, Suite 102, Lincoln, Nebraska 68508-2243 (United States)

2014-07-15T23:59:59.000Z

77

Towards Managing Variability in the Safety Design of an Automotive Hall Effect Sensor  

E-Print Network [OSTI]

Towards Managing Variability in the Safety Design of an Automotive Hall Effect Sensor Dimitri Van) as the main devel- opment process for an automotive Hall Effect sensor. This versatile component is integrated for every automotive application in which the sensor is to be used. In addition, no support is given

Paris-Sud XI, Université de

78

Effective field theory for fluids: Hall viscosity from a Wess-Zumino-Witten term  

E-Print Network [OSTI]

We propose an effective action that describe a relativistic fluid with Hall viscosity. The construction involves a Wess-Zumino-Witten term that exists only in (2+1) spacetime dimensions. We note that this formalism can accommodate only a Hall viscosity which is a homogeneous function of the entropy and particle number densities of degree one.

Michael Geracie; Dam Thanh Son

2014-11-11T23:59:59.000Z

79

Genomic instability and bystander effects induced by high-LET radiation Eric J Hall*,1  

E-Print Network [OSTI]

Genomic instability and bystander effects induced by high-LET radiation Eric J Hall*,1 and Tom K. There is a progressive increase in genomic instability, determined either by gene amplification or allelic imbalance

80

Visualizing edge states with an atomic Bose gas in the quantum Hall regime  

E-Print Network [OSTI]

We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux ~4/3 times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip, with single lattice-site resolution along the narrow direction. Further, we observed both the skipping orbits of excited atoms traveling down our system's edges, analogues to edge magnetoplasmons in 2-D electron systems, and a dynamical Hall effect for bulk excitations. Our lattice's long direction consisted of the sites of an optical lattice and its narrow direction consisted of the internal atomic spin states. Our technique has minimal heating, a feature that will be important for spectroscopic measurements of the Hofstadter butterfly and realizations of Laughlin's charge pump.

B. K. Stuhl; H. -I Lu; L. M. Aycock; D. Genkina; I. B. Spielman

2015-02-09T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Visualizing edge states with an atomic Bose gas in the quantum Hall regime  

E-Print Network [OSTI]

We engineered a two-dimensional magnetic lattice in an elongated strip geometry, with effective per-plaquette flux ~4/3 times the flux quanta. We imaged the localized edge and bulk states of atomic Bose-Einstein condensates in this strip, with single lattice-site resolution along the narrow direction. Further, we observed both the skipping orbits of excited atoms traveling down our system's edges, analogues to edge magnetoplasmons in 2-D electron systems, and a dynamical Hall effect for bulk excitations. Our lattice's long direction consisted of the sites of an optical lattice and its narrow direction consisted of the internal atomic spin states. Our technique has minimal heating, a feature that will be important for spectroscopic measurements of the Hofstadter butterfly and realizations of Laughlin's charge pump.

Stuhl, B K; Aycock, L M; Genkina, D; Spielman, I B

2015-01-01T23:59:59.000Z

82

Electroweak Hall Effect of Neutrino and Coronal Heating  

E-Print Network [OSTI]

The inversion of temperature at the solar corona is hard to understand from classical physics, and the coronal heating mechanism remains unclear. The heating in the quiet region seems contradicting with the thermodynamics and is a keen problem for physicists. A new mechanism for the coronal heating based on the neutrino radiative transition unique in the corona region is studied. The probability is enormously amplified by an electroweak Chern-Simons form and overlapping waves, and the sufficient energy is transfered. Thus the coronal heating is understood from the quantum effects of the solar neutrino.

Ishikawa, Kenzo

2015-01-01T23:59:59.000Z

83

488 Brazilian Journal of Physics, vol. 36, no. 2A, June, 2006 Spin Valve Effect and Hall Resistance in a Wide Parabolic Well  

E-Print Network [OSTI]

488 Brazilian Journal of Physics, vol. 36, no. 2A, June, 2006 Spin Valve Effect and Hall Resistance: Spin valve; Hall resistance; AlcGa1-cAs parabolic wells I. INTRODUCTION The Hall effect is very known by the formula Rxy = R0B+RSM, where B is ap- plied magnetic field, R0 is the ordinary Hall coefficient, and RS

Gusev, Guennady

84

-MODEL No: HMS5300-* Product Name : Hall Effect Measurement  

E-Print Network [OSTI]

-IT55T3) 2-3) How to input the gas valve 3) Bolt screw in and out , to lock in and lock out magnet 4) LN, resistivity, conductivity, hall coefficient 4) Test in Low temperature by using Liquid Nitrogen (1) Pour ~ Gas In 8'CDheater ®motor r .. ~ Pic#4 AHT55T3 rear view > 5 #12;2-3) How to input the gas valve Insert

Woodall, Jerry M.

85

Highly tunable quantum Hall far-infrared photodetector by use of GaAs/Al{sub x}Ga{sub 1?x}As-graphene composite material  

SciTech Connect (OSTI)

We have developed a highly tunable, narrow band far-infrared (FIR) photodetector which utilizes the characteristic merits of graphene and two-dimensional electron gas (2DEG) in GaAs/Al{sub x}Ga{sub 1?x}As heterostructure in the Quantum Hall states (QHS). The heterostructure surface is covered with chemical vapor-deposited graphene, which functions as a transparent top-gate to vary the electron density of the 2DEG. FIR response observed in the vicinity of integer QH regime can be effectively tuned in a wide range of 27–102?cm{sup ?1} with a bias voltage less than ?1?V. In addition, we have found that the presence of graphene can genuinely modulate the photoresponse. Our results demonstrate a promising direction for realizing a tunable long-wavelength FIR detector using QHS in GaAs 2DEG/ graphene composite material.

Tang, Chiu-Chun [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2014-11-03T23:59:59.000Z

86

Radial scale effect on the performance of low-power cylindrical Hall plasma thrusters  

SciTech Connect (OSTI)

Investigation of the radial scale effect on low-power cylindrical Hall thrusters has been undertaken by comparing the thrusters with three different channel diameters of 28, 40, and 50 mm. The investigation found that both the anode efficiency and the thrust of the larger thruster are higher as the anode power is raised. On the other hand, higher current and propellant utilizations are achieved for the smaller thruster, which is due to higher neutral density and better electron confinement. The large plume angle of the small cylindrical Hall thruster causes thrust loss, resulting in the reduction of anode efficiency.

Seo, Mihui; Lee, Jongsub; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)] [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Seon, Jongho [School of Space Research, Kyung Hee University, 1732 Deokyoungdaero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)] [School of Space Research, Kyung Hee University, 1732 Deokyoungdaero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); June Lee, Hae [Department of Electrical Engineering, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of)] [Department of Electrical Engineering, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

2013-09-23T23:59:59.000Z

87

Experimental evidences of a large extrinsic spin Hall effect in AuW alloy  

SciTech Connect (OSTI)

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.

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

88

Plasma-Induced Erosion on Ceramic Wall Structures in Hall-Effect Thrusters  

E-Print Network [OSTI]

Plasma-Induced Erosion on Ceramic Wall Structures in Hall-Effect Thrusters Thomas Burton University expansion of BN in the amorphous silica matrix. Exfoliation accompanied the microcracking in BN and resulted]. There have been several studies on ion-based erosion in ceramic materials [5­8,10­17]. The mechanisms

Walker, Mitchell

89

Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect  

SciTech Connect (OSTI)

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.

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

90

PREPRINT QUASIPARTICLE AGGREGATION I N THE FRACTIONAL QUANTUM HALL EFFECT  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 - September 2006 TheSteven Ashby Dr. Steven AshbystationAbout UsBOEPREP |

91

Robert B. Laughlin and the Fractional Quantum Hall Effect  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0 Resource Program September

92

Design and characterization of a low cost dual differential proving ring force sensor utilizing Hall-effect sensors  

E-Print Network [OSTI]

A novel dual differential hall-effect based proving ring force sensor has been designed, manufactured, and tested. Strain gauge based force sensors are among the most common methods of measuring static and dynamic forces, ...

Rivest, Christopher W. (Christopher Warren)

2006-01-01T23:59:59.000Z

93

Electric Field effects on quantum correlations in semiconductor quantum dots  

E-Print Network [OSTI]

We study the effect of external electric bias on the quantum correlations in the array of optically excited coupled semiconductor quantum dots. The correlations are characterized by the quantum discord and concurrence and are observed using excitonic qubits. We employ the lower bound of concurrence for thermal density matrix at different temperatures. The effect of the F\\"orster interaction on correlations will be studied. Our theoretical model detects nonvanishing quantum discord when the electric field is on while concurrence dies, ensuring the existence of nonclassical correlations as measured by the quantum discord.

S. Shojaei; M. Mahdian; R. Yousefjani

2012-05-01T23:59:59.000Z

94

Effective equations for quantum dynamics  

E-Print Network [OSTI]

We report on recent results concerning the derivation of effective evolution equations starting from many body quantum dynamics. In particular, we obtain rigorous derivations of nonlinear Hartree equations in the bosonic mean field limit, with precise bounds on the rate of convergence. Moreover, we present a central limit theorem for the fluctuations around the Hartree dynamics.

Benjamin Schlein

2012-08-01T23:59:59.000Z

95

Inverse spin Hall effect induced by spin pumping into semiconducting ZnO  

SciTech Connect (OSTI)

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.

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

96

Quantum mechanical effects from deformation theory  

SciTech Connect (OSTI)

We consider deformations of quantum mechanical operators by using the novel construction tool of warped convolutions. The deformation enables us to obtain several quantum mechanical effects where electromagnetic and gravitomagnetic fields play a role. Furthermore, a quantum plane can be defined by using the deformation techniques. This in turn gives an experimentally verifiable effect.

Much, A. [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)] [Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany and Institute for Theoretical Physics, University of Leipzig, 04009 Leipzig (Germany)

2014-02-15T23:59:59.000Z

97

Nuclear quantum effects in water  

E-Print Network [OSTI]

In this work, a path integral Car-Parrinello molecular dynamics simulation of liquid water is performed. It is found that the inclusion of nuclear quantum effects systematically improves the agreement of first principles simulations of liquid water with experiment. In addition, the proton momentum distribution is computed utilizing a recently developed open path integral molecular dynamics methodology. It is shown that these results are in good agreement with neutron Compton scattering data for liquid water and ice.

Joseph A. Morrone; Roberto Car

2008-03-25T23:59:59.000Z

98

Resonant cavity mode dependence of anomalous and inverse spin Hall effect  

SciTech Connect (OSTI)

The direct current electric voltage induced by the Inverse Spin Hall Effect (ISHE) and Anomalous Hall Effect (AHE) was investigated in the TE{sub 011} and TE{sub 102} cavities. The ISHE and AHE components were distinguishable through the fitting of the voltage spectrum. The unwanted AHE was minimized by placing the DUT (Device Under Test) at the center of both the TE{sub 011} and TE{sub 102} cavities. The voltage of ISHE in the TE{sub 011} cavity was larger than that in the TE{sub 102} cavity due to the higher quality factor of the former. Despite optimized centering, AHE voltage from TE{sub 011} cavity was also higher. The reason was attributed to the E-field distribution inside the cavity. In the case of the TE{sub 011} cavity, the DUT was easily exposed to the E-field in all directions. Therefore, the parasitic AHE voltage in the TE{sub 102} cavity was less sensitive than that in the TE{sub 011} cavity to decentering problem.

Kim, Sang-Il; Seo, Min-Su; Park, Seung-young, E-mail: parksy@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of)

2014-05-07T23:59:59.000Z

99

Quantum Field Theory in Graphene  

E-Print Network [OSTI]

This is a short non-technical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.

I. V. Fialkovsky; D. V. Vassilevich

2011-11-18T23:59:59.000Z

100

Effect of the annular region on the performance of a cylindrical Hall plasma thruster  

SciTech Connect (OSTI)

Performance characteristics of a cylindrical Hall thruster depending on the depth of the annular region (L{sub a}) in front of the anode were investigated. The effect of the annular region was examined by operating thrusters corresponding to four different values of L{sub a} (0, 4, 6, and 10 mm) and a fixed length of the cylindrical region (25 mm). Various measurements such as electron and ion currents, thrust, anode efficiency, current and propellant utilizations, and ion energy distribution functions were performed. Such measurements lead to an interpretation that (1) a considerable potential difference may exist between the anode and the ionization region, which is presumably located near the end of the annular region where magnetic field lines converge; (2) this potential difference increases with respect to increasing L{sub a}; and (3) the presence of the annular region near the anode reduces the specific impulse and anode efficiency for the examined thrusters.

Seo, Mihui; Lee, Jongsub; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Seon, Jongho [School of Space Research, Kyung Hee University, 1732 Deokyoungdaero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); June Lee, Hae [Department of Electrical Engineering, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

2013-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers.  

SciTech Connect (OSTI)

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.

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

102

Local far-infrared spectroscopy of edge states in the quantum Hall regime A. Lorke* and J. P. Kotthaus  

E-Print Network [OSTI]

resolution well below typical Hall bar dimensions,7,8 the other is the use of the edge channels them- selves are as follows: Buffer and smoothing layers, 1 m GaAs, a 15-nm AlxGa1 xAs (x 0.3) spacer layer, 3.9 1012 - cm 2

Ludwig-Maximilians-Universität, München

103

Cost-Effective Fabrication Routes for the Production of Quantum...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Production of Quantum Well Type Structures and Recovery of Waste Heat from Heavy Duty Trucks Cost-Effective Fabrication Routes for the Production of Quantum Well Type Structures...

104

Direct measurement of the Hall effect in a free-electron-like surface state Toru Hirahara, Iwao Matsuda,* Canhua Liu, Rei Hobara, Shinya Yoshimoto, and Shuji Hasegawa  

E-Print Network [OSTI]

a number of reports on the Hall effect and magnetoresistance at metal or metal silicide ultrathin films- or alkali-metal atoms on the surface, the electron pocket becomes larger because electrons are doped

Hasegawa, Shuji

105

Charge Hall effect driven by spin-dependent chemical potential gradients and Onsager relations in mesoscopic systems RID B-8398-2011 RID A-7392-2009  

E-Print Network [OSTI]

We study theoretically the spin-Hall effect as well as its reciprocal phenomenon (a transverse charge current driven by a spin-dependent chemical potential gradient) in electron and hole finite size mesoscopic systems. The Landauer...

Hankiewicz, EM; Li, J.; Jungwirth, T.; Niu, Q.; Shen, SQ; Sinova, Jairo.

2005-01-01T23:59:59.000Z

106

Large anomalous Hall effect in ferromagnetic insulator-topological insulator heterostructures  

SciTech Connect (OSTI)

We demonstrate the van der Waals epitaxy of the topological insulator compound Bi{sub 2}Te{sub 3} on the ferromagnetic insulator Cr{sub 2}Ge{sub 2}Te{sub 6}. The layers are oriented with (001)Bi{sub 2}Te{sub 3}||(001)Cr{sub 2}Ge{sub 2}Te{sub 6} and (110)Bi{sub 2}Te{sub 3}||(100)Cr{sub 2}Ge{sub 2}Te{sub 6}. Cross-sectional transmission electron microscopy indicates the formation of a sharp interface. At low temperatures, bilayers consisting of Bi{sub 2}Te{sub 3} on Cr{sub 2}Ge{sub 2}Te{sub 6} exhibit a large anomalous Hall effect (AHE). Tilted field studies of the AHE indicate that the easy axis lies along the c-axis of the heterostructure, consistent with magnetization measurements in bulk Cr{sub 2}Ge{sub 2}Te{sub 6}. The 61?K Curie temperature of Cr{sub 2}Ge{sub 2}Te{sub 6} and the use of near-stoichiometric materials may lead to the development of spintronic devices based on the AHE.

Alegria, L. D.; Petta, J. R. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States); Ji, H.; Cava, R. J. [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States); Yao, N. [Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544 (United States); Clarke, J. J. [Hitachi High Technologies America, Inc., Clarksburg, Maryland 20871 (United States)

2014-08-04T23:59:59.000Z

107

Classification of macroscopic quantum effects  

E-Print Network [OSTI]

We review canonical experiments on systems that have pushed the boundary between the quantum and classical worlds towards much larger scales, and discuss their unique features that enable quantum coherence to survive. Because the types of systems differ so widely, we use a case by case approach to identifying the different parameters and criteria that capture their behaviour in a quantum mechanical framework. We find it helpful to categorise systems into three broad classes defined by mass, spatio-temporal coherence, and number of particles. The classes are not mutually exclusive and in fact the properties of some systems fit into several classes. We discuss experiments by turn, starting with interference of massive objects like macromolecules and micro-mechanical resonators, followed by self-interference of single particles in complex molecules, before examining the striking advances made with superconducting qubits. Finally, we propose a theoretical basis for quantifying the macroscopic features of a system to lay the ground for a more systematic comparison of the quantum properties in disparate systems.

Tristan Farrow; Vlatko Vedral

2014-06-03T23:59:59.000Z

108

Quantum effects in nanoscale Josephson junction circuits  

E-Print Network [OSTI]

Quantum effects in nanoscale Josephson junction circuits SILVIA CORLEVI Doctoral Thesis Stockholm Josephson junction arrays with SQUID geometry. TRITA FYS 2006:31 ISSN 0280-316X ISRN KTH/FYS/­06:31­SE ISBN study on single-charge effects in nanoscale Josephson junctions and Cooper pair transistors (CPTs

Haviland, David

109

Quantum plasma effects in the classical regime  

E-Print Network [OSTI]

For quantum effects to be significant in plasmas it is often assumed that the temperature over density ratio must be small. In this paper we challenge this assumption by considering the contribution to the dynamics from the electron spin properties. As a starting point we consider a multicomponent plasma model, where electrons with spin up and spin down are regarded as different fluids. By studying the propagation of Alfv\\'{e}n wave solitons we demonstrate that quantum effects can survive in a relatively high-temperature plasma. The consequences of our results are discussed.

G. Brodin; M. Marklund; G. Manfredi

2008-02-01T23:59:59.000Z

110

Blue quantum electroabsorption modulators based on reversed quantum confined Stark effect with blueshift  

E-Print Network [OSTI]

Blue quantum electroabsorption modulators based on reversed quantum confined Stark effect of blue quantum electroabsorption modulators that incorporate 5 nm thick In0.35Ga0.65N/GaN quantum cm-1 for 6 V bias swing around 424 nm, holding promise for blue optical clock generation

Demir, Hilmi Volkan

111

The Quantum-Classical and Mind-Brain Linkages: The Quantum Zeno Effect in Binocular Rivalry  

E-Print Network [OSTI]

A quantum mechanical theory of the relationship between perceptions and brain dynamics based on von Neumann's theory of measurments is applied to a recent quantum theoretical treatment of binocular rivaly that makes essential use of the quantum Zeno effect to give good fits to the complex available empirical data. The often-made claim that decoherence effects in the warm, wet, noisy brain must eliminate quantum effects at the macroscopic scale pertaining to perceptions is examined, and it is argued, on the basis of fundamental principles. that the usual decoherence effects will not upset the quantum Zeno effect that is being exploited in the cited work.

Henry P. Stapp

2007-11-05T23:59:59.000Z

112

Quantum Mechanical Effects in Gravitational Collapse  

E-Print Network [OSTI]

In this thesis we investigate quantum mechanical effects to various aspects of gravitational collapse. These quantum mechanical effects are implemented in the context of the Functional Schr\\"odinger formalism. The Functional Schr\\"odinger formalism allows us to investigate the time-dependent evolutions of the quantum mechanical effects, which is beyond the scope of the usual methods used to investigate the quantum mechanical corrections of gravitational collapse. Utilizing the time-dependent nature of the Functional Schr\\"odinger formalism, we study the quantization of a spherically symmetric domain wall from the view point of an asymptotic and infalling observer, in the absence of radiation. To build a more realistic picture, we then study the time-dependent nature of the induced radiation during the collapse using a semi-classical approach. Using the domain wall and the induced radiation, we then study the time-dependent evolution of the entropy of the domain wall. Finally we make some remarks about the possible inclusion of backreaction into the system.

Eric Greenwood

2010-01-12T23:59:59.000Z

113

Wall current closure effects on plasma and sheath fluctuations in Hall thrusters  

SciTech Connect (OSTI)

The excitation of negative energy, ion sound type modes driven by the E?×?B drift and the reactive/dissipative response of the wall sheath interface is analyzed for conditions typical in a Hall thruster. Such sheath impedance modes are sensitive to the dielectric properties of the thruster wall material, which therefore may have direct influence (other than via the secondary electron emission) on fluctuations and transport. Our results predict mode frequencies consistent with the frequencies of fluctuations observed experimentally.

Frias, Winston, E-mail: wpf274@mail.usask.ca; Smolyakov, Andrei I. [Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kaganovich, Igor D.; Raitses, Yevgeny [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-06-15T23:59:59.000Z

114

.......Agnew Hall .......Air Conditioning Facility  

E-Print Network [OSTI]

/Burleson Tennis Center .......Burruss Hall .......Campbell Hall .......Cassell Coliseum .......Central Stores .......Dietrick Hall .......Durham Hall .......Eggleston Hall .......Engel Hall D.....English Field .......Femoyer .......Golf Course Clubhouse .......Graduate Life Center at ........Donaldson Brown .......Greenhouses

Buehrer, R. Michael

115

The effect of inertia on the Dirac electron, the spin Hall current and the momentum space Berry curvature  

SciTech Connect (OSTI)

We have studied the spin dependent force and the associated momentum space Berry curvature in an accelerating system. The results are derived by taking into consideration the non-relativistic limit of a generally covariant Dirac equation with an electromagnetic field present, where the methodology of the Foldy-Wouthuysen transformation is applied to achieve the non-relativistic limit. Spin currents appear due to the combined action of the external electric field, the crystal field and the induced inertial electric field via the total effective spin-orbit interaction. In an accelerating frame, the crucial role of momentum space Berry curvature in the spin dynamics has also been addressed from the perspective of spin Hall conductivity. For time dependent acceleration, the expression for the spin polarization has been derived. - Highlights: Black-Right-Pointing-Pointer We study the effect of acceleration on the Dirac electron in the presence of an electromagnetic field, where the acceleration induces an electric field. Black-Right-Pointing-Pointer Spin currents appear due to the total effective electric field via the total spin-orbit interaction. Black-Right-Pointing-Pointer We derive the expression for the spin dependent force and the spin Hall current, which is zero for a particular acceleration. Black-Right-Pointing-Pointer The role of the momentum space Berry curvature in an accelerating system is discussed. Black-Right-Pointing-Pointer An expression for the spin polarization for time dependent acceleration is derived.

Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

2013-02-15T23:59:59.000Z

116

Spin current and inverse spin Hall effect in ferromagnetic metals probed by Y{sub 3}Fe{sub 5}O{sub 12}-based spin pumping  

SciTech Connect (OSTI)

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.

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

117

Grand Unification and Enhanced Quantum Gravitational Effects  

SciTech Connect (OSTI)

In grand unified theories with large numbers of fields, renormalization effects significantly modify the scale at which quantum gravity becomes strong. This in turn can modify the boundary conditions for coupling constant unification, if higher dimensional operators induced by gravity are taken into consideration. We show that the generic size of, and the uncertainty in, these effects from gravity can be larger than the two-loop corrections typically considered in renormalization group analyses of unification. In some cases, gravitational effects of modest size can render unification impossible.

Calmet, Xavier [Catholic University of Louvain, Center for Particle Physics and Phenomenology, 2, Chemin du Cyclotron, B-1348 Louvain-la-Neuve (Belgium); Hsu, Stephen D. H.; Reeb, David [Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403 (United States)

2008-10-24T23:59:59.000Z

118

Cost-Effective Fabrication Routes for the Productionof Quantum...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Productionof Quantum-Well-Type Structures and Recovoery of Waste Heat from Heavy-Duty Trucks Cost-Effective Fabrication Routes for the Productionof Quantum-Well-Type Structures and...

119

The MSW Effect in Quantum Field Theory  

E-Print Network [OSTI]

We show in detail the general relationship between the Schr\\"{o}dinger equation approach to calculating the MSW effect and the quantum field theoretical S-matrix approach. We show the precise form a generic neutrino propagator must have to allow a physically meaningful ``oscillation probability'' to be decoupled from neutrino production fluxes and detection cross-sections, and explicitly list the conditions---not realized in cases of current experimental interest---in which the field theory approach would be useful.

Christian Y. Cardall; Daniel J. H. Chung

1999-04-12T23:59:59.000Z

120

Disorder effects in the anomalous Hall effect induced by Berry curvature RID B-5617-2009  

E-Print Network [OSTI]

in ferromagnets results from the interplay of the ex- change field, which breaks the time-reversal symmetry, and the spin-orbit coupling, that violates the chiral symmetry. Interestingly, at the same time a similar effect was predicted and explained... of the distribution function in a single band at zero temperature: Jyx #1;clean#2; = e#8; d2kf0#1;k#2;vy#1;a#2; = e#8; 0 kF kdk#8; 0 2#5; d#6; #1;2#5;#2;2eExFz = e2ExFzkF 2 4#5; , #1;5#2; where f0#1;k#2; is the equilibrium distribution function and k...

Sinitsyn, NA; Niu, Q.; Sinova, Jairo; Nomura, K.

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Quantum confined Stark effect in Gaussian quantum wells: A tight-binding study  

SciTech Connect (OSTI)

The main characteristics of the quantum confined Stark effect (QCSE) are studied theoretically in quantum wells of Gaussian profile. The semi-empirical tight-binding model and the Green function formalism are applied in the numerical calculations. A comparison of the QCSE in quantum wells with different kinds of confining potential is presented.

Ramírez-Morales, A.; Martínez-Orozco, J. C.; Rodríguez-Vargas, I. [Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac. (Mexico)

2014-05-15T23:59:59.000Z

122

Quantum resistance standard accuracy close to the zero-dissipation state  

SciTech Connect (OSTI)

We report on a comparison of four GaAs/AlGaAs-based quantum resistance standards using an original technique adapted from the well-known Wheatstone bridge. This work shows that the quantized Hall resistance at Landau level filling factor ?=2 can be reproducible with a relative uncertainty of 32×10{sup ?12} in the dissipationless limit of the quantum Hall effect regime. In the presence of a very small dissipation characterized by a mean macroscopic longitudinal resistivity R{sub xx}(B) of a few ??, the discrepancy ?R{sub H}(B) between quantum Hall resistors measured on the Hall plateau at magnetic induction B turns out to follow the so-called resistivity rule R{sub xx}(B)=?B×d(?R{sub H}(B))/dB. While the dissipation increases with the measurement current value, the coefficient ? stays constant in the range investigated (40?120 ?A). This result enlightens the impact of the dissipation emergence in the two-dimensional electron gas on the Hall resistance quantization, which is of major interest for the resistance metrology. The quantum Hall effect is used to realize a universal resistance standard only linked to the electron charge e and the Planck constant h and it is known to play a central role in the upcoming revised Système International of units. There are therefore fundamental and practical benefits in testing the reproducibility property of the quantum Hall effect with better and better accuracy.

Schopfer, F.; Poirier, W. [Laboratoire National de métrologie et d'Essais (LNE), 29 avenue Roger Hennequin, 78197 Trappes (France)] [Laboratoire National de métrologie et d'Essais (LNE), 29 avenue Roger Hennequin, 78197 Trappes (France)

2013-08-14T23:59:59.000Z

123

The Hall  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism in Layered NbS2 and NbSe2DifferentThe FiveD. The LawThe H2The H2Hall

124

Topological Quantum Computation by Manipulating Quantum Tunneling Effect of the Toric Codes  

E-Print Network [OSTI]

Quantum computers are predicted to utilize quantum states to perform memory and to process tasks far faster than those of conventional classical computers. In this paper we show a new road towards building fault tolerance quantum computer by tuning quantum tunneling effect of the degenerate quantum states in topological order, instead of by braiding anyons. Using a designer Hamiltonian - the Wen-Plaquette model as an example, we study its quantum tunneling effect of the toric codes and show how to control the toric code to realize topological quantum computation (TQC). In particular, we give a proposal to the measurement of TQC. In the end the realization of the Wen-Plaquette model in cold atoms is discussed.

Su-Peng Kou

2008-06-10T23:59:59.000Z

125

Unruh effect, quantum thermometer and geometric phase  

E-Print Network [OSTI]

We analyze the properties of the geometric phase of a two level atom system in the case in which the atoms are accelerated by an external potential and in the case in which they interact with a thermal state. Non-trivial values of the geometric phases are obtained. We then propose the realization of an interferometer in which the analysis of Mukunda-Simon phase can demonstrate the existence of the Unruh effect. The realization of a very precise quantum thermometer is also discussed.

A. Capolupo; G. Vitiello

2015-02-02T23:59:59.000Z

126

Quantum Coherence Effects in Novel Quantum Optical Systems  

E-Print Network [OSTI]

and find interesting applications. We show that quantum coherence can lead to transient Raman lasing and lasing without inversion in short wavelength spectral regions--extreme ultraviolet and x-ray--without the requirement of incoherent pumping. For example...

Sete, Eyob Alebachew

2012-10-19T23:59:59.000Z

127

E-Print Network 3.0 - annular hall thrusters Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Plasma Physics and Fusion 48 Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster Summary: in for annular Hall thrusters. A transition...

128

Spin-dependent Hall effect in a parabolic well with a quasi-three-dimensional electron gas G. M. Gusev, C. A. Duarte, A. A. Quivy, T. E. Lamas, and J. R. Leite*  

E-Print Network [OSTI]

dependent coefficient, and is the angle between the magnetic field and the normal to the well plane valve tran- sistor or other spintronic devices, however, the existence of such a spin-dependent property has not been studied yet in transport coefficients. Only the recently spin-related quantum Hall

Gusev, Guennady

129

Weightlessness of photons: A quantum effect  

E-Print Network [OSTI]

Contrary to general belief, the Fraunhofer lines have been found to be plasma redshifted and not gravitationally redshifted, when observed on Earth. Quantum mechanical effects cause the photons' gravitational redshift to be reversed as the photons move from the Sun to the Earth. The designs of the experiments, which were thought to have proven the gravitational redshift of photons, are all in the domain of classical physics, and make it impossible to detect the reversal of the gravitational redshifts. The solar redshift experiments, however, are in the domain of quantum mechanics; and the reversal of the redshift is easily detected, when the plasma redshift is taken into account. The photons are found to be weightless relative to a local observer, but repelled relative to a distant observer. The weightlessness of the photons in the gravitational field relative to a local observer is inconsistent with Einstein's equivalence principle. This together with the plasma redshift has profound consequences for the cosmological perspectives. This article gives a theoretical explanation of the observed phenomena, proper interpretation of the many gravitational redshift experiments, and an understanding of how we missed observing the reversal of photons' gravitational redshift. The present analysis indicates that although the photons are weightless in a local system of reference, the experimental evidence indicates that quasi-static electromagnetic fields are not weightless, but adhere to the principle of equivalence.

Ari Brynjolfsson

2006-02-17T23:59:59.000Z

130

Stability of Quantum Fluids : Wavy Interface Effect  

E-Print Network [OSTI]

A numerical investigation for the stability of the incompressible slip flow of normal quantum fluids (above the critical phase transition temperature) inside a microslab where surface acoustic waves propagate along the walls is presented. Governing equations and associated slip velocity and wavy interface boundary conditions for the flow of normal fluids confined between elastic wavy interfaces are obtained. The numerical approach is an extension (with a complex matrix pre-conditioning) of the spectral method. We found that the critical Reynolds number ($Re_{cr}$ or the critical velocity) decreases significantly once the slip velocity and wavy interface effects are present and the latter is dominated ($Re_{cr}$ mainly depends on the wavy interfaces).

A. Kwang-Hua Chu

2005-08-31T23:59:59.000Z

131

Casimir effect from macroscopic quantum electrodynamics  

E-Print Network [OSTI]

The canonical quantization of macroscopic electromagnetism was recently presented in New J. Phys. 12 (2010) 123008. This theory is here used to derive the Casimir effect, by considering the special case of thermal and zero-point fields. The stress-energy-momentum tensor of the canonical theory follows from Noether's theorem, and its electromagnetic part in thermal equilibrium gives the Casimir energy density and stress tensor. The results hold for arbitrary inhomogeneous magnetodielectrics and are obtained from a rigorous quantization of electromagnetism in dispersive, dissipative media. Continuing doubts about the status of the standard Lifshitz theory as a proper quantum treatment of Casimir forces do not apply to the derivation given here. Moreover, the correct expressions for the Casimir energy density and stress tensor inside media follow automatically from the simple restriction to thermal equilibrium, without the need for complicated thermodynamical or mechanical arguments.

T. G. Philbin

2011-06-09T23:59:59.000Z

132

Joint manifestation of fractional quantum Hall effect and insulating behavior in graphene at high magnetic fields  

E-Print Network [OSTI]

This paper (concerning the infinite-mass boundary condition) has been withdrawn by the author. Another, independent study regarding the zigzag boundary condition has appeared in Phys. Rev. B 82, 125419 (2010).

Igor Romanovsky; Constantine Yannouleas; Uzi Landman

2010-09-10T23:59:59.000Z

133

Quantum size effects in classical hadrodynamics  

SciTech Connect (OSTI)

The author discusses future directions in the development of classical hydrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic nucleus-nucleus collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. The present version of the theory includes only the neutral scalar ({sigma}) and neutral vector ({omega}) meson fields. In the future, additional isovector pseudoscalar ({pi}{sup +}, {pi}{sup {minus}}, {pi}{sup 0}), isovector vector ({rho}{sup +}, {rho}{sup {minus}}, {rho}{sup 0}), and neutral pseudoscalar ({eta}) meson fields should be incorporated. Quantum size effects should be included in the equations of motion by use of the spreading function of Moniz and Sharp, which generates an effective nucleon mass density smeared out over a Compton wavelength. However, unlike the situation in electrodynamics, the Compton wavelength of the nucleon is small compared to its radius, so that effects due to the intrinsic size of the nucleon dominate.

Nix, J.R.

1994-03-01T23:59:59.000Z

134

2D massless QED Hall half-integer conductivity and graphene  

E-Print Network [OSTI]

Starting from the photon self-energy tensor in a magnetized medium, the 3D complete antisymmetric form of the conductivity tensor is found in the static limit of a fermion system $C$ non-invariant under fermion-antifermion exchange. The massless relativistic 2D fermion limit in QED is derived by using the compactification along the dimension parallel to the magnetic field. In the static limit and at zero temperature the main features of quantum Hall effect (QHE) are obtained: the half-integer QHE and the minimum value proportional to $e^2/h$ for the Hall conductivity . For typical values of graphene the plateaus of the Hall conductivity are also reproduced.

A. Pérez Martínez; E. Rodriguez Querts; H. Pérez Rojas; R. Gaitan; S. Rodriguez Romo

2011-10-13T23:59:59.000Z

135

Experimental Study of the Hall Effect and Electron Diffusion Region During Magnetic Reconnection in a Laboratory Plasma  

SciTech Connect (OSTI)

The Hall effect during magnetic reconnection without an external guide field has been extensively studied in the laboratory plasma of the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys. Plasmas 4, 1936 (1997)] by measuring its key signature, an out-of-plane quadrupole magnetic field, with magnetic probe arrays whose spatial resolution is on the order of the electron skin depth. The in-plane electron flow is deduced from out-of-plane magnetic field measurements. The measured in-plane electron flow and numerical results are in good agreement. The electron diffusion region is identified by measuring the electron outflow channel. The width of the electron diffusion region scales with the electron skin depth (~ 8c/?pe) and the peak electron outflow velocity scales with the electron Alfven velocity (~ 0:11VeA), independent of ion mass. The measured width of the electron diffusion region is much wider and the observed electron outflow is much slower than those obtained in 2D numerical simulations. It is found that the classical and anomalous dissipation present in the experiment can broaden the electron diffusion region and slow the electron outflow. As a consequence, the electron outflow flux remain consistent with numerical simulations. The ions, as measured by a Mach probe, have a much wider outflow channel than the electrons, and their outflow is much slower than the electron outflow everywhere in the electron diffusion region.

Ren, Yang; Yamada, Masaaki; Ji, Hantao; Dorfman, Seth; Gerhardt, Stefan; Kulsrud, Russel

2008-07-02T23:59:59.000Z

136

Quantum Wavepacket Ab Initio Molecular Dynamics: An Approach for Computing Dynamically Averaged Vibrational Spectra Including Critical Nuclear Quantum Effects  

E-Print Network [OSTI]

Vibrational Spectra Including Critical Nuclear Quantum Effects Isaiah Sumner and Srinivasan S. Iyengar to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach the vibrational density of states of [Cl-H-Cl]- , inclusive of critical quantum nuclear effects, and our results

Iyengar, Srinivasan S.

137

Wright Hall "0 250 500125  

E-Print Network [OSTI]

. 211 Kenny Rd. Field House Pound Hall 202 McGowan Rd. 213 Kenny Rd. Warehouse Wright Hall Quarters B

Arnold, Jonathan

138

E-Print Network 3.0 - atomic quantum registers Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

frustrated magnets and fractional quantum Hall systems to cold atoms and Josephson junction arrays. We... -22 April 2011 Jadwin Hall Fourth Floor, Room 407 Topological...

139

Monte Carlo simulation of quantum Zeno effect in the brain  

E-Print Network [OSTI]

Environmental decoherence appears to be the biggest obstacle for successful construction of quantum mind theories. Nevertheless, the quantum physicist Henry Stapp promoted the view that the mind could utilize quantum Zeno effect to influence brain dynamics and that the efficacy of such mental efforts would not be undermined by environmental decoherence of the brain. To address the physical plausibility of Stapp's claim, we modeled the brain using quantum tunneling of an electron in a multiple-well structure such as the voltage sensor in neuronal ion channels and performed Monte Carlo simulations of quantum Zeno effect exerted by the mind upon the brain in the presence or absence of environmental decoherence. The simulations unambiguously showed that the quantum Zeno effect breaks down for timescales greater than the brain decoherence time. To generalize the Monte Carlo simulation results for any n-level quantum system, we further analyzed the change of brain entropy due to the mind probing actions and proved a theorem according to which local projections cannot decrease the von Neumann entropy of the unconditional brain density matrix. The latter theorem establishes that Stapp's model is physically implausible but leaves a door open for future development of quantum mind theories provided the brain has a decoherence-free subspace.

Danko Georgiev

2014-12-11T23:59:59.000Z

140

Housing services Zinfandel Hall  

E-Print Network [OSTI]

resources, the library, and the Internet. The Community has its own dining hall, swimming pools, study roomsHousing services Zinfandel Hall (707) 664-2541 Fax: (707) 664-4158 e-mail: ssu hall suites and campus apartments, all located just seconds from the main campus classroom buildings

Ravikumar, B.

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Two quantum effects in the theory of gravitation  

E-Print Network [OSTI]

We will discuss two methods by which the formalism of quantum field theory can be included in calculating the physical effects of gravitation. In the first of these, the consequences of treating general relativity as an ...

Robinson, Sean Patrick, 1977-

2005-01-01T23:59:59.000Z

142

Quantum effects in electron beam pumped GaAs  

SciTech Connect (OSTI)

Propagation of waves in nano-sized GaAs semiconductor induced by electron beam are investigated. A dispersion relation is derived by using quantum hydrodynamics equations including the electrons and holes quantum recoil effects, exchange-correlation potentials, and degenerate pressures. It is found that the propagating modes are instable and strongly depend on the electron beam parameters, as well as the quantum recoil effects and degenerate pressures. The instability region shrinks with the increase of the semiconductor number density. The instability arises because of the energetic electron beam produces electron-hole pairs, which do not keep in phase with the electrostatic potential arising from the pair plasma.

Yahia, M. E. [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt) [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Azzouz, I. M. [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt)] [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)

2013-08-19T23:59:59.000Z

143

Optimal Quantum Pumps  

E-Print Network [OSTI]

We study adiabatic quantum pumps on time scales that are short relative to the cycle of the pump. In this regime the pump is characterized by the matrix of energy shift which we introduce as the dual to Wigner's time delay. The energy shift determines the charge transport, the dissipation, the noise and the entropy production. We prove a general lower bound on dissipation in a quantum channel and define optimal pumps as those that saturate the bound. We give a geometric characterization of optimal pumps and show that they are noiseless and transport integral charge in a cycle. Finally we discuss an example of an optimal pump related to the Hall effect.

J. E. Avron; A. Elgart; G. M. Graf; L. Sadun

2001-07-12T23:59:59.000Z

144

Comparison of Secondary Islands in Collisional Reconnection to Hall Reconnection  

SciTech Connect (OSTI)

Large-scale resistive Hall-magnetohydrodynamic simulations of the transition from Sweet-Parker (collisional) to Hall (collisionless) magnetic reconnection are presented; the first to separate secondary islands from collisionless effects. Three main results are described. There exists a regime with secondary islands but without collisionless effects, and the reconnection rate is faster than Sweet-Parker, but significantly slower than Hall reconnection. This implies that secondary islands do not cause the fastest reconnection rates. The onset of Hall reconnection ejects secondary islands from the vicinity of the X line, implying that energy is released more rapidly during Hall reconnection. Coronal applications are discussed.

Shepherd, L. S.; Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia, 26506 (United States)

2010-07-02T23:59:59.000Z

145

Joule heating-induced coexisted spin Seebeck effect and spin Hall magnetoresistance in the platinum/Y{sub 3}Fe{sub 5}O{sub 12} structure  

SciTech Connect (OSTI)

Spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) are observed simultaneously in the Pt/Y{sub 3}Fe{sub 5}O{sub 12} hybrid structure when thermal gradient is produced by Joule heating. According to their dependences on applied current, these two effects can be separated. Their dependence on heating power and magnetic field is systematically studied. With the increase of heating power, the SSE enhances linearly, whereas the SMR decreases slowly. The origin of the spin currents is further analyzed. The heating power dependences of the spin currents associated with the SSE and the SMR are found to be different.

Wang, W. X. [State Key Laboratory of Advance Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. H.; Zou, L. K.; Cai, J. W.; Sun, J. R., E-mail: jrsun@iphy.ac.cn, E-mail: sun-zg@whut.edu.cn [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Sun, Z. G. [State Key Laboratory of Advance Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2014-11-03T23:59:59.000Z

146

Effective Theories of Coupled Classical and Quantum Variables  

E-Print Network [OSTI]

We address the issue of coupling variables which are essentially classical to variables that are quantum. Two approaches are discussed. In the first (based on collaborative work with L.Di\\'osi), continuous quantum measurement theory is used to construct a phenomenological description of the interaction of a quasiclassical variable $X$ with a quantum variable $x$, where the quasiclassical nature of $X$ is assumed to have come about as a result of decoherence. The state of the quantum subsystem evolves according to the stochastic non-linear Schr\\"odinger equation of a continuously measured system, and the classical system couples to a stochastic c-number $\\x (t)$ representing the imprecisely measured value of $x$. The theory gives intuitively sensible results even when the quantum system starts out in a superposition of well-separated localized states. The second approach involves a derivation of an effective theory from the underlying quantum theory of the combined quasiclassical--quantum system, and uses the decoherent histories approach to quantum theory.

J. J. Halliwell

1998-08-26T23:59:59.000Z

147

Quantum effects improve the energy efficiency of feedback control  

E-Print Network [OSTI]

The laws of thermodynamics apply equally well to quantum systems as to classical systems, and because of this quantum effects do not change the fundamental thermodynamic efficiency of isothermal refrigerators or engines. We show that, despite this fact, quantum mechanics permits measurement-based feedback control protocols that are more thermodynamically efficient than their classical counterparts. As part of our analysis we perform a detailed accounting of the thermodynamics of unitary feedback control, and elucidate the sources of inefficiency in measurement-based and coherent feedback.

Jordan M. Horowitz; Kurt Jacobs

2014-04-15T23:59:59.000Z

148

Exchange effects in magnetized quantum plasmas  

E-Print Network [OSTI]

We apply the many-particle quantum hydrodynamics including the Coulomb exchange interaction to magnetized quantum plasmas. We consider a number of wave phenomenon under influence of the Coulomb exchange interaction. Since the Coulomb exchange interaction affects longitudinal and transverse-longitudinal waves we focus our attention to the Langmuir waves, Trivelpiece-Gould waves, ion-acoustic waves in non-isothermal magnetized plasmas, the dispersion of the longitudinal low-frequency ion-acoustic waves and low-frequencies electromagnetic waves at $T_{e}\\gg T_{i}$ . We obtained the numerical simulation of the dispersion properties of different types of waves.

Trukhanova, Mariya Iv

2015-01-01T23:59:59.000Z

149

Quantum effects in unimolecular reaction dynamics  

SciTech Connect (OSTI)

This work is primarily concerned with the development of models for the quantum dynamics of unimolecular isomerization and photodissociation reactions. We apply the rigorous quantum methodology of a Discrete Variable Representation (DVR) with Absorbing Boundary Conditions (ABC) to these models in an attempt to explain some very surprising results from a series of experiments on vibrationally excited ketene. Within the framework of these models, we are able to identify the experimental signatures of tunneling and dynamical resonances in the energy dependence of the rate of ketene isomerization. Additionally, we investigate the step-like features in the energy dependence of the rate of dissociation of triplet ketene to form {sup 3}B{sub 1} CH{sub 2} + {sup 1}{sigma}{sup +} CO that have been observed experimentally. These calculations provide a link between ab initio calculations of the potential energy surfaces and the experimentally observed dynamics on these surfaces. Additionally, we develop an approximate model for the partitioning of energy in the products of photodissociation reactions of large molecules with appreciable barriers to recombination. In simple bond cleavage reactions like CH{sub 3}COCl {yields} CH{sub 3}CO + Cl, the model does considerably better than other impulsive and statistical models in predicting the energy distribution in the products. We also investigate ways of correcting classical mechanics to include the important quantum mechanical aspects of zero-point energy. The method we investigate is found to introduce a number of undesirable dynamical artifacts including a reduction in the above-threshold rates for simple reactions, and a strong mixing of the chaotic and regular energy domains for some model problems. We conclude by discussing some of the directions for future research in the field of theoretical chemical dynamics.

Gezelter, J.D.

1995-12-01T23:59:59.000Z

150

Entangling photons via the double quantum Zeno effect  

SciTech Connect (OSTI)

We propose a scheme for entangling two photons via the quantum Zeno effect, which describes the inhibition of quantum evolution by frequent measurements and is based on the difference between summing amplitudes and probabilities. For a given error probability P{sub error}, our scheme requires that the one-photon loss rate {xi}{sub 1{gamma}} and the two-photon absorption rate {xi}{sub 2{gamma}} in some medium satisfy {xi}{sub 1{gamma}}/{xi}{sub 2{gamma}}=2P{sub error}{sup 2}/{pi}{sup 2}, which is significantly improved compared to previous approaches. Again based on the quantum Zeno effect, as well as coherent excitations, we present a possibility to fulfill this requirement in an otherwise linear optics setup.

Brinke, Nicolai ten; Osterloh, Andreas; Schuetzhold, Ralf [Fakultaet fuer Physik, Universitaet Duisburg-Essen, Lotharstrasse 1, D-47057 Duisburg (Germany)

2011-08-15T23:59:59.000Z

151

Contracting Around Hall Street  

E-Print Network [OSTI]

This Article examines the extent to which expanded court review of arbitration awards remains available after the Supreme Court’s decision in Hall Street Associates, L.L.C. v. Mattel, Inc. - that is, whether parties can contract around Hall Street...

Drahozal, Christopher R.

2010-01-01T23:59:59.000Z

152

HAMILTON, ONTARIO HAMILTON HALL  

E-Print Network [OSTI]

HAMILTON, ONTARIO L8S 4K1 HAMILTON HALL ROOM 103A Phone: (905) 525-9140 Ext. 20297/24682 Fax: (905.doc #12;HAMILTON, ONTARIO L8S 4K1 HAMILTON HALL ROOM 103A (905) 525-9140 Ext. 20297/24682 Fax: (905) 522

Thompson, Michael

153

HAMILTON, ONTARIO HAMILTON HALL  

E-Print Network [OSTI]

HAMILTON, ONTARIO L8S 4K1 HAMILTON HALL ROOM 103A 905-525-9140 EXT. 24682 FAX: 905-522-8320 mufa:\\My Documents\\General Meetings\\Apr 28-11\\agenda.wpd #12;HAMILTON, ONTARIO L8S 4K1 HAMILTON HALL ROOM 103A 905

Thompson, Michael

154

Instanton effects and quantum spectral curves  

E-Print Network [OSTI]

We study a spectral problem associated to the quantization of a spectral curve arising in local mirror symmetry. The perturbative WKB quantization condition is determined by the quantum periods, or equivalently by the refined topological string in the Nekrasov-Shatashvili (NS) limit. We show that the information encoded in the quantum periods is radically insufficient to determine the spectrum: there is an infinite series of instanton corrections, which are non-perturbative in \\hbar, and lead to an exact WKB quantization condition. Moreover, we conjecture the precise form of the instanton corrections: they are determined by the standard or un-refined topological string free energy, and we test our conjecture successfully against numerical calculations of the spectrum. This suggests that the non-perturbative sector of the NS refined topological string contains information about the standard topological string. As an application of the WKB quantization condition, we explain some recent observations relating membrane instanton corrections in ABJM theory to the refined topological string.

Johan Kallen; Marcos Marino

2014-04-16T23:59:59.000Z

155

Macroscopic quantum tunneling and the 'cosmic' Josephson effect  

SciTech Connect (OSTI)

We discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the 'false vacuum'. We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/high-temperature superconducting devices.

Barone, A. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', CNR-SPIN, Piazzale Tecchio 21, 80125 Napoli (Italy); Gasperini, M. [Dipartimento di Fisica, Universita di Bari, Via G. Amendola 173, 70126 Bari (Italy); INFN, Sezione di Bari, Bari (Italy); Rotoli, G. [Dipartimento di Ingegneria dell'Informazione, Seconda Universita di Napoli (SUN), Via Roma 29, 81031 Aversa (CE) (Italy)

2010-10-15T23:59:59.000Z

156

Scaling of Decoherence Effects in Quantum Computers  

E-Print Network [OSTI]

The scaling of decoherence rates with the number of q-bits is studied for a simple quantum computer model. Two state q-bits are localised around well-separated positions via trapping potentials, but vibrational motion of q-bits centre of mass motion occurs. Coherent one and two q-bit gating processes are controlled by external classical fields and facilitated by a high Q cavity mode. Decoherence due to q-bit and cavity mode coupling to a bath of spontaneous emission modes, cavity decay modes and to the vibrational modes is treated. A non-Markovian treatment of the short time behaviour of the fidelity is presented, enabling time scales for decoherence to be determined, together with their dependence on q-bit number for the case where the q-bit/cavity mode system is in a pure state and the baths are in thermal states.

B. J. Dalton

2003-01-17T23:59:59.000Z

157

Hall A Annual Report 2013  

SciTech Connect (OSTI)

Report over the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013.

Dalton, Mark M.

2014-02-01T23:59:59.000Z

158

Hall A Annual Report 2013  

E-Print Network [OSTI]

Report over the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013.

M. M. Dalton; K. Allada; K. Aniol; W. Boeglin; A. Camsonne; E. Chudakov; M. Cummings; D. Flay; M. Friedman; O. Glamazdin; J. Gomez; C. Keppel; H. P. Khanal; R. Lindgren; E. Long; R. Michaels; M. Mihovilovi?; C. Muñoz Camacho; S. Nanda; R. Pomatsalyuk; S. Riordan; S. Širca; C. Smith; P. Solvignon; N. F. Sparveris; V. Vereshchaka; X. Yan; Z. Ye; Y. X. Zhao; Jefferson Lab Hall A Collaboration

2014-02-27T23:59:59.000Z

159

Quantum corrections to spin effects in general relativity  

E-Print Network [OSTI]

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.

G. G. Kirilin

2005-07-16T23:59:59.000Z

160

Effective time-independent analysis for quantum kicked systems  

E-Print Network [OSTI]

We present a mapping of potentially chaotic time-dependent quantum kicked systems to an equivalent effective time-independent scenario, whereby the system is rendered integrable. The time-evolution is factorized into an initial kick, followed by an evolution dictated by a time-independent Hamiltonian and a final kick. This method is applied to the kicked top model. The effective time-independent Hamiltonian thus obtained, does not suffer from spurious divergences encountered if the traditional Baker-Cambell-Hausdorff treatment is used. The quasienergy spectrum of the Floquet operator is found to be in excellent agreement with the energy levels of the effective Hamiltonian for a wide range of system parameters. The density of states for the effective system exhibits sharp peak-like features, pointing towards quantum criticality. The dynamics in the classical limit of the integrable effective Hamiltonian shows remarkable agreement with the non-integrable map corresponding to the actual time-dependent system in the non-chaotic regime. This suggests that the effective Hamiltonian serves as a substitute for the actual system in the non-chaotic regime at both the quantum and classical level.

Jayendra N. Bandyopadhyay; Tapomoy Guha Sarkar

2014-09-04T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Growing quantum states with topological order  

E-Print Network [OSTI]

We discuss a protocol for growing states with topological order in interacting many-body systems using a sequence of flux quanta and particle insertion. We first consider a simple toy model, the superlattice Bose Hubbard model, to explain all required ingredients. Our protocol is then applied to fractional quantum Hall systems in both, continuum and lattice. We investigate in particular how the fidelity, with which a topologically ordered state can be grown, scales with increasing particle number N. For small systems exact diagonalization methods are used. To treat large systems with many particles, we introduce an effective model based on the composite fermion description of the fractional quantum Hall effect. This model also allows to take into account the effects of dispersive bands and edges in the system, which will be discussed in detail.

Letscher, Fabian; Fleischhauer, Michael

2015-01-01T23:59:59.000Z

162

On the implications of the Quantum-Pigeonhole Effect  

E-Print Network [OSTI]

There has been considerable interest in a recent preprint - arXiv/1407.3194 - describing an effect named as the Quantum Pigeonhole Principle. The classical pigeonhole principle (classical PHP) refers to a result in number theory which states that if n objects are distributed between m boxes, with m less than n, then at least one box must contain more than one object. An experiment is proposed in the preprint where interactions between particles would reveal that they were in the same box, but a quantum mechanical measurement would imply that no more than 1 of the n objects is contained in any of the m boxes, even though n is greater than m. This result has been greeted by the authors of the preprint and some others as being of great importance in the understanding of quantum mechanics. In this paper we show by a full quantum mechanical treatment that the effect appears to arise as a result of interference between the components of the wavefunctions, each of which is subject to the classical PHP.

Alastair Rae; Ted Forgan

2014-12-04T23:59:59.000Z

163

JOURNAL DE PHYSIQUE Colloque C5, suppliment au no 5, Tome 40, Mai 1979, page C5-38 Magnetoresistance and anomalous Hall effect of magnesium singIe crystals  

E-Print Network [OSTI]

-38 Magnetoresistance and anomalous Hall effect of magnesium singIe crystals with heavy rare earth impurities J. Bijvoet splitting, the magnetization of rare earth ions in magnesium single crystals is anisotropic at low and cannot be explained by crystal field splitting of the 4f levels. Single crystals of magnesium with small

Paris-Sud XI, Université de

164

Florence Moore Wilbur Hall  

E-Print Network [OSTI]

Main Quad Escondido VillageManzanita Park Graduate School of Business; Knight Management Center Truck Hse. Clock Tower Owen Bolivar House Haas Center Galvez Modular Sweet Hall Bookstore Law School

Bogyo, Matthew

165

Hall Ammendment Policy  

Broader source: Energy.gov [DOE]

Joint statement providing interim policy on processing proposals for leasing DOE real property using the authority in 42 U.S.C. 7256, commonly referred to as the "Hall Amendment."

166

Energy spectrum, dissipation, and spatial structures in reduced Hall magnetohydrodynamic  

SciTech Connect (OSTI)

We analyze the effect of the Hall term in the magnetohydrodynamic turbulence under a strong externally supported magnetic field, seeing how this changes the energy cascade, the characteristic scales of the flow, and the dynamics of global magnitudes, with particular interest in the dissipation. Numerical simulations of freely evolving three-dimensional reduced magnetohydrodynamics are performed, for different values of the Hall parameter (the ratio of the ion skin depth to the macroscopic scale of the turbulence) controlling the impact of the Hall term. The Hall effect modifies the transfer of energy across scales, slowing down the transfer of energy from the large scales up to the Hall scale (ion skin depth) and carrying faster the energy from the Hall scale to smaller scales. The final outcome is an effective shift of the dissipation scale to larger scales but also a development of smaller scales. Current sheets (fundamental structures for energy dissipation) are affected in two ways by increasing the Hall effect, with a widening but at the same time generating an internal structure within them. In the case where the Hall term is sufficiently intense, the current sheet is fully delocalized. The effect appears to reduce impulsive effects in the flow, making it less intermittent.

Martin, L. N.; Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Gomez, D. O. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio, CONICET, Buenos Aires (Argentina)

2012-05-15T23:59:59.000Z

167

E-Print Network 3.0 - asymmetric coupled quantum Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

systems in the fractional quantum Hall regime. Ben... the quantum dynamics of mesoscopic Josephson junctions. They showed that the coherent tunneling of Cooper pair Source: Busch,...

168

Electron-wall interaction in Hall thrustersa... Y. Raitsesb  

E-Print Network [OSTI]

Electron-wall interaction in Hall thrustersa... Y. Raitsesb and D. Staack Princeton Plasma Physics; accepted 22 February 2005; published online 2 May 2005 Electron-wall interaction effects in Hall thrusters this threshold, the electron energy gain is constant in the acceleration region and therefore, secondary electron

169

Post-Newtonian gravitational effects in quantum interferometry  

E-Print Network [OSTI]

We investigate general properties of optical interferometry in stationary spacetimes and apply the obtained results focusing on quantum-optical experiments in near-Earth environments. We provide a rigorous expression for the {gravitationally induced} phase difference and adapt the parametrized post-Newtonian formalism for calculations of polarization rotation. We investigate two optical versions of the Colella-Overhauser-Werner experiment and show that the phase difference is independent of the post-Newtonian parameter $\\gamma$, making it a possible candidate for an optical test of the Einstein equivalence principle. Polarization rotation provides an example of the quantum clock variable, and while related to the optical Lense-Thirring effects, shows a qualitatively different behaviour.

Aharon Brodutch; Alexei Gilchrist; Thomas Guff; Alexander R. H. Smith; Daniel R. Terno

2014-12-08T23:59:59.000Z

170

Effect of Quantum Fluctuations on the Dipolar Motion of Bose-Einstein Condensates in Optical Lattices  

E-Print Network [OSTI]

Effect of Quantum Fluctuations on the Dipolar Motion of Bose-Einstein Condensates in Optical of condensate atoms in one-dimensional optical lattices and harmonic magnetic traps including quantum is reduced, on the contrary, strong quantum fluctuations lead to finite damping of condensate oscillations

Wang, Daw-Wei

171

Effect of quantum nuclear motion on hydrogen bonding  

SciTech Connect (OSTI)

This work considers how the properties of hydrogen bonded complexes, X–H?Y, are modified by the quantum motion of the shared proton. Using a simple two-diabatic state model Hamiltonian, the analysis of the symmetric case, where the donor (X) and acceptor (Y) have the same proton affinity, is carried out. For quantitative comparisons, a parametrization specific to the O–H?O complexes is used. The vibrational energy levels of the one-dimensional ground state adiabatic potential of the model are used to make quantitative comparisons with a vast body of condensed phase data, spanning a donor-acceptor separation (R) range of about 2.4 ? 3.0 Å, i.e., from strong to weak hydrogen bonds. The position of the proton (which determines the X–H bond length) and its longitudinal vibrational frequency, along with the isotope effects in both are described quantitatively. An analysis of the secondary geometric isotope effect, using a simple extension of the two-state model, yields an improved agreement of the predicted variation with R of frequency isotope effects. The role of bending modes is also considered: their quantum effects compete with those of the stretching mode for weak to moderate H-bond strengths. In spite of the economy in the parametrization of the model used, it offers key insights into the defining features of H-bonds, and semi-quantitatively captures several trends.

McKenzie, Ross H., E-mail: r.mckenzie@uq.edu.au; Bekker, Christiaan [School of Mathematics and Physics, University of Queensland, Brisbane 4072 (Australia)] [School of Mathematics and Physics, University of Queensland, Brisbane 4072 (Australia); Athokpam, Bijyalaxmi; Ramesh, Sai G. [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012 (India)] [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012 (India)

2014-05-07T23:59:59.000Z

172

Prototype dining hall energy efficiency study  

SciTech Connect (OSTI)

The energy consumption of food service facilities is among the highest of any commercial building type, owing to the special requirements for food preparation, sanitation, and ventilation. Consequently, the US Air Force Engineering and Services Center (AFESC) contracted with Pacific Northwest Laboratory (PNL) to collect and analyze end-use energy consumption data for a prototypical dining hall and make specific recommendations on cost-effective energy conservation options. This information will be used to establish or update criteria for dining hall designs and retrofits as appropriate. 6 refs., 21 figs., 23 tabs.

Mazzucchi, R.P.; Bailey, S.A.; Zimmerman, P.W.

1988-06-01T23:59:59.000Z

173

Effect of phase transition on quantum transport in group-IV two-dimensional U-shape device  

SciTech Connect (OSTI)

The effect of phase-transition from the quantum-spin-hall to the band-insulator phase on the transport through a three-terminal U-shape spin-separator has been computationally investigated via non-equilibrium green function formalism. Two-dimensional group-IV elements have been comprehensively appraised as the device material. The device separates the unpolarized current injected at the source-terminal into nearly 100% spin-polarized currents of the opposite polarities at the two drain terminals. The phase-transition activated by the electric-field orthogonal to the device is shown to extensively influence the current magnitude and its spin-polarization, and the effect is stronger for materials with smaller intrinsic spin-orbit coupling. Moreover, the device length and the area under field are shown to critically affect the device characteristics on phase change. It is shown that the same device can be operated as a spin-filter by inducing phase-transition selectively in the channel. The results are important for designing spin-devices from Group-IV monolayers.

Sadi, Mohammad Abdullah; Gupta, Gaurav, E-mail: a0089293@nus.edu.sg; Liang, Gengchiau [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2014-10-21T23:59:59.000Z

174

On Quantum Coherence Effects in Photo and Solar Cells  

E-Print Network [OSTI]

We show that quantum coherence can increase the quantum efficiency of various thermodynamic systems. For example, we can enhance the quantum efficiency for a quantum dot photocell, a laser based solar cell and the photo-Carnot quantum heat engine. Our results are fully consistent with the laws of thermodynamics contrary to comments found in the paper of A.P. Kirk, Phys. Rev. Lett. 106, 048703 (2011).

Kimberly Chapin; Konstantin Dorfman; Anatoly Svidzinsky; Marlan Scully

2011-02-01T23:59:59.000Z

175

Micro-focused Brillouin light scattering study of the magnetization dynamics driven by Spin Hall effect in a transversely magnetized NiFe nanowire  

E-Print Network [OSTI]

We employed micro-focused Brillouin light scattering to study the amplification of the thermal spin wave eigenmodes by means of a pure spin current, generated by the spin-Hall effect, in a transversely magnetized Pt(4nm)/NiFe(4nm)/SiO2(5nm) layered nanowire with lateral dimensions 500x2750 nm2. The frequency and the cross section of both the center (fundamental) and the edge spin wave modes have been measured as a function of the intensity of the injected dc electric current. The frequency of both modes exhibits a clear redshift while their cross section is greatly enhanced on increasing the intensity of the injected dc. A threshold-like behavior is observed for a value of the injected dc of 2.8 mA. Interestingly an additional mode, localized in the central part of the nanowire, appears at higher frequency on increasing the intensity of the injected dc above the threshold value. Micromagnetic simulations were used to quantitatively reproduce the experimental results and to investigate the complex non-linear d...

Madami, M; Moriyama, T; Tanaka, K; Siracusano, G; Carpentieri, M; Finocchio, G; Tacchi, S; Ono, T; Carlotti, G

2015-01-01T23:59:59.000Z

176

Measurement of XeI and XeII velocity in the near exit plane of a low-power Hall effect thruster by light induced fluorescence spectroscopy  

SciTech Connect (OSTI)

Near exit plane non-resonant light induced fluorescence spectroscopy is performed in a Hall effect low-power Xenon thruster at discharge voltage of 250 V and anode flow rate of 0.7 mg/s. Measurements of the axial and radial velocity components are performed, exciting the 6s{sup 2}[3/2]{sub 2}{sup o}{yields}6p{sup 2}[3/2]{sub 2} transition at 823.16 nm in XeI and the 5d[4]{sub 7/2}{yields}6p[3]{sub 5/2}{sup o} transition at 834.724 nm in XeII. No significant deviation from the thermal velocity is observed for XeI. Two most probable ion velocities are registered at a given position with respect to the thruster axis, which are mainly attributed to different areas of creation of ions inside the acceleration channel. The spatial resolution of the set-up is limited by the laser beam size (radius of the order of 0.5 mm) and the fluorescence collection optics, which have a view spot diameter of 8 mm.

Dancheva, Y. [CNISM, University of Siena, CSC and DSFTA, via Roma 56, 53100 Siena (Italy); Biancalana, V. [CNISM, University of Siena, CSC and DIISM, via Roma 56, 53100 Siena (Italy); Pagano, D.; Scortecci, F. [Aerospazio Tecnologie Srl., via Provinciale Nord 42a, 53040 Rapolano Terme (Italy)

2013-06-15T23:59:59.000Z

177

The Casimir effect: from quantum to critical fluctuations  

E-Print Network [OSTI]

The Casimir effect in quantum electrodynamics (QED) is perhaps the best-known example of fluctuation-induced long-ranged force acting on objects (conducting plates) immersed in a fluctuating medium (quantum electromagnetic field in vacuum). A similar effect emerges in statistical physics, where the force acting, e.g., on colloidal particles immersed in a binary liquid mixture is affected by the classical thermal fluctuations occurring in the surrounding medium. The resulting Casimir-like force acquires universal features upon approaching a critical point of the medium and becomes long-ranged at criticality. In turn, this universality allows one to investigate theoretically the temperature dependence of the force via representative models and to stringently test the corresponding predictions in experiments. In contrast to QED, the Casimir force resulting from critical fluctuations can be easily tuned with respect to strength and sign by surface treatments and temperature control. We present some recent advances in the theoretical study of the universal properties of the critical Casimir force arising in thin films. The corresponding predictions compare very well with the experimental results obtained for wetting layers of various fluids. We discuss how the Casimir force between a colloidal particle and a planar wall immersed in a binary liquid mixture has been measured with femto-Newton accuracy, comparing these experimental results with the corresponding theoretical predictions.

Andrea Gambassi

2008-12-04T23:59:59.000Z

178

The trouble with orbits: the Stark effect in the old and the new quantum theory  

E-Print Network [OSTI]

The old quantum theory and Schr\\"odinger's wave mechanics (and other forms of quantum mechanics) give the same results for the line splittings in the first-order Stark effect in hydrogen, the leading terms in the splitting of the spectral lines emitted by a hydrogen atom in an external electric field. We examine the account of the effect in the old quantum theory, which was hailed as a major success of that theory, from the point of view of wave mechanics. First, we show how the new quantum mechanics solves a fundamental problem one runs into in the old quantum theory with the Stark effect. It turns out that, even without an external field, it depends on the coordinates in which the quantum conditions are imposed which electron orbits are allowed in a hydrogen atom. The allowed energy levels and hence the line splittings are independent of the coordinates used but the size and eccentricity of the orbits are not. In the new quantum theory, this worrisome non-uniqueness of orbits turns into the perfectly innocuous non-uniqueness of bases in Hilbert space. Second, we review how the so-called WKB (Wentzel-Kramers-Brillouin) approximation method for solving the Schr\\"odinger equation reproduces the quantum conditions of the old quantum theory amended by some additional half-integer terms. These extra terms remove the need for some arbitrary extra restrictions on the allowed orbits that the old quantum theory required over and above the basic quantum conditions

Anthony Duncan; Michel Janssen

2014-04-21T23:59:59.000Z

179

Nonequilibrium phonon effects in midinfrared quantum cascade lasers  

SciTech Connect (OSTI)

We investigate the effects of nonequilibrium phonon dynamics on the operation of a GaAs-based midinfrared quantum cascade laser over a range of temperatures (77–300?K) via a coupled ensemble Monte Carlo simulation of electron and optical-phonon systems. Nonequilibrium phonon effects are shown to be important below 200?K. At low temperatures, nonequilibrium phonons enhance injection selectivity and efficiency by drastically increasing the rate of interstage electron scattering from the lowest injector state to the next-stage upper lasing level via optical-phonon absorption. As a result, the current density and modal gain at a given field are higher and the threshold current density lower and considerably closer to experiment than results obtained with thermal phonons. By amplifying phonon absorption, nonequilibrium phonons also hinder electron energy relaxation and lead to elevated electronic temperatures.

Shi, Y. B., E-mail: yshi9@wisc.edu; Knezevic, I., E-mail: knezevic@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706-1691 (United States)

2014-09-28T23:59:59.000Z

180

Cylindrical geometry hall thruster  

DOE Patents [OSTI]

An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, wherein ions are accelerated in substantially the axial direction. The apparatus is suitable for operation at low power. It employs small size thruster components, including a ceramic channel, with the center pole piece of the conventional annular design thruster eliminated or greatly reduced. Efficient operation is accomplished through magnetic fields with a substantial radial component. The propellant gas is ionized at an optimal location in the thruster. A further improvement is accomplished by segmented electrodes, which produce localized voltage drops within the thruster at optimally prescribed locations. The apparatus differs from a conventional Hall thruster, which has an annular geometry, not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume.

Raitses, Yevgeny (Princeton, NJ); Fisch, Nathaniel J. (Princeton, NJ)

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Quantum effects in the diffusion of hydrogen on Ru(0001)  

E-Print Network [OSTI]

An understanding of hydrogen diffusion on metal surfaces is important, not just for its role in heterogeneous catalysis and hydrogen fuel cell technology, but also because it provides model systems where tunneling can be studied under well-defined conditions. Here we report helium spin-echo measurements of the atomic-scale motion of hydrogen on the Ru(0001) surface between 75 and 250 K. Quantum effects are evident at temperatures as high as 200 K, while below 120 K we observe a tunneling-dominated temperature independent jump rate of 1.9$\\times$10$^9$ s$^{-1}$, many orders of magnitude faster than previously seen. Quantum transition state theory calculations based on ab initio path-integral simulations reproduce the temperature dependence of the rate at higher temperatures and predict a crossover to tunneling-dominated diffusion at low temperatures, although the tunneling rate is under-estimated, highlighting the need for future experimental and theoretical studies of hydrogen diffusion on well-defined surfac...

McIntosh, Eliza M; Ellis, John; Michaelides, Angelos; Allison, William

2014-01-01T23:59:59.000Z

182

Aharonov-Casher and spin Hall effects in mesoscopic ring structures with strong spin-orbit interaction RID A-1315-2011 RID B-3617-2008  

E-Print Network [OSTI]

at certain values of the SO interaction and the same does not hold in the multichannel devices.14 In addition, Souma and Nikoli?15 calculated the spin Hall conductance of ring struc- tures and found that the spin Hall conductance is also modu- lated... and due to the subtleties introduced by the SO interactions, it does not suffice to discard the derivatives in the radial direction and set r=r0 in the 2D Hamiltonian. The single-particle 1D Hamiltonian is found by assuming that the confining potential...

Borunda, M. F.; Liu, Xin; Kovalev, Alexey A.; Liu, Xiong-Jun; Jungwirth, T.; Sinova, Jairo.

2008-01-01T23:59:59.000Z

183

The effect of dust size distribution on quantum dust acoustic wave  

SciTech Connect (OSTI)

Based on the quantum hydrodynamics theory, a proposed model for quantum dust acoustic waves (QDAWs) is presented including the dust size distribution (DSD) effect. A quantum version of Zakharov-Kuznetsov equation is derived adequate for describing QDAWs. Two different DSD functions are applied. The relevance of the wave velocity, amplitude, and width to the DSD is investigated numerically. The quantum effect changes only the soliton width. A brief conclusion is presented to the current findings and their relevance to astrophysics data is also discussed.

El-Labany, S. K.; El-Taibany, W. F.; Behery, E. E. [Department of Physics, Faculty of Science, Mansoura University, Damietta Branch, Damietta El-Gedida, P.O. 34517 (Egypt); El-Siragy, N. M. [Department of Physics, Faculty of Science, Tanta University, Tanta, P.O. 31527 (Egypt)

2009-09-15T23:59:59.000Z

184

Why are the effective equations of loop quantum cosmology so accurate?  

E-Print Network [OSTI]

We point out that the relative Heisenberg uncertainty relations vanish for non-compact spaces in homogeneous loop quantum cosmology. As a consequence, for sharply peaked states quantum fluctuations in the scale factor never become important, even near the bounce point. This shows why quantum back-reaction effects remain negligible and explains the surprising accuracy of the effective equations in describing the dynamics of sharply peaked wave packets. This also underlines the fact that minisuperspace models ---where it is global variables that are quantized--- do not capture the local quantum fluctuations of the geometry.

Carlo Rovelli; Edward Wilson-Ewing

2014-07-25T23:59:59.000Z

185

'Dark Matter' as a Quantum Foam In-Flow Effect  

E-Print Network [OSTI]

The galactic `dark matter' effect is regarded as one of the major problems in fundamental physics. Here it is explained as a self-interaction dynamical effect of space itself, and so is not caused by an unknown form of matter. Because it was based on Kepler's Laws for the motion of the planets in the solar system the Newtonian theory of gravity was too restricted. A reformulation and generalisation of the Newtonian theory of gravity in terms of a velocity in-flow field, representing at a classical level the relative motion of a quantum-foam substructure to space, reveals a key dynamical feature of the phenomenon of gravity, namely the so called `dark matter' effect, which manifests not only in spiral galaxy rotation curves, but also in the borehole g anomaly, globular and galactic black holes, and in ongoing problems in improving the accuracy with which Newton's gravitational constant G is measured. The new theory of gravity involves an additional new dimensionless gravitational constant, and experimental data reveals this to be the fine structure constant. The new theory correctly predicts the globular cluster black hole masses, and that the `frame-dragging' effect is caused by vorticity in the in-flow. The relationship of the new theory of gravity to General Relativity which, like Newtonian gravity, does not have the `dark matter' dynamics, is explained.

Reginald T. Cahill

2005-08-25T23:59:59.000Z

186

Quantum fluctuations and isotope effects in ab initio descriptions of water  

E-Print Network [OSTI]

Nuclear quantum effects, such as zero-point energy and tunneling, cause significant changes to the structure and dynamics of hydrogen bonded systems such as liquid water. However, due to the current inability to simulate liquid water using an exact description of its electronic structure, the interplay between nuclear and electronic quantum effects remains unclear. Here we use simulations that incorporate the quantum mechanical nature of both the nuclei and electrons to provide a fully ab initio determination of the particle quantum kinetic energies, free energy change upon exchanging hydrogen for deuterium and the isotope fractionation ratio in water. These properties, which selectively probe the quantum nature of the nuclear degrees of freedom, allow us to make direct comparison to recent experiments and elucidate how electronic exchange and correlation and nuclear quantum fluctuations determine the structure of the hydrogen bond in water.

Lu Wang; Michele Ceriotti; Thomas E. Markland

2014-06-24T23:59:59.000Z

187

Quantum Zeno effect and the impossibility of determining the quantum state of a single system Orly Alter and Yoshihisa Yamamoto  

E-Print Network [OSTI]

to monitor this time evolution using the measurement results. This effect is shown to be equivalent the statistics of the results of a series of measurements performed on a single system, with no time evolution of measurements are independent of the measurement results. Therefore it was also suggested that the quantum Zeno

Utah, University of

188

K-7109Agnew Hall M-2204Air Conditioning Plant  

E-Print Network [OSTI]

Building] K-4171Burchard Hall L-4176Burruss Hall L-637Campbell Hall - East Wing L-636Campbell Hall - Main Center at Donaldson Brown L-9124Greenhouse Q-10 241Grounds Building (Central Stores) J-4 158Hahn Hall

Buehrer, R. Michael

189

Quantum fluctuations and isotope effects in ab initio descriptions of water  

SciTech Connect (OSTI)

Isotope substitution is extensively used to investigate the microscopic behavior of hydrogen bonded systems such as liquid water. The changes in structure and stability of these systems upon isotope substitution arise entirely from the quantum mechanical nature of the nuclei. Here, we provide a fully ab initio determination of the isotope exchange free energy and fractionation ratio of hydrogen and deuterium in water treating exactly nuclear quantum effects and explicitly modeling the quantum nature of the electrons. This allows us to assess how quantum effects in water manifest as isotope effects, and unravel how the interplay between electronic exchange and correlation and nuclear quantum fluctuations determine the structure of the hydrogen bond in water.

Wang, Lu; Markland, Thomas E., E-mail: tmarkland@stanford.edu [Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305 (United States); Ceriotti, Michele, E-mail: michele.ceriotti@epfl.ch [Laboratory of Computational Science and Modeling, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland)

2014-09-14T23:59:59.000Z

190

Rhodes Hall Ross Heart Hospital  

E-Print Network [OSTI]

Emergency 315 315 26 Rhodes Hall Ross Heart Hospital James Cancer Hospital Martha Morehouse.m. James Cancer Hospital 7:10 a.m. Rhodes Hall 7:13 a.m. Ross Heart Hospital 7:15 a.m. Martha Morehouse

Howat, Ian M.

191

QER- Comment of Addison Hall  

Broader source: Energy.gov [DOE]

I and my family own land in Ashfield next to the proposed Kinder Morgan/Tennessee Pipeline route. We are opposed to the pipeline for a variety of reasons, including the highly questionable need for the proposed commodity increase and the inevitable damage to the environment and communities along the proposed route. Addison Hall for the Hall Family Trust.

192

Numerical simulations of a loop quantum cosmos: robustness of the quantum bounce and the validity of effective dynamics  

E-Print Network [OSTI]

A key result of isotropic loop quantum cosmology is the existence of a quantum bounce which occurs when the energy density of the matter field approaches a universal maximum close to the Planck density. Though the bounce has been exhibited in various matter models, due to severe computational challenges some important questions have so far remained unaddressed. These include the demonstration of the bounce for widely spread states, its detailed properties for the states when matter field probes regions close to the Planck volume and the reliability of the continuum effective spacetime description in general. In this manuscript we rigorously answer these questions using the Chimera numerical scheme for the isotropic spatially flat model sourced with a massless scalar field. We show that as expected from an exactly solvable model, the quantum bounce is a generic feature of states even with a very wide spread, and for those which bounce much closer to the Planck volume. We perform a detailed analysis of the departures from the effective description and find some expected, and some surprising results. At a coarse level of description, the effective dynamics can be regarded as a good approximation to the underlying quantum dynamics unless the states correspond to small scalar field momenta, in which case they bounce closer to the Planck volume, or are very widely spread. Quantifying the amount of discrepancy between the quantum and the effective dynamics, we find that the departure between them depends in a subtle and non-monotonic way on the field momentum and different fluctuations. Interestingly, the departures are generically found to be such that the effective dynamics overestimates the spacetime curvature, and underestimates the volume at the bounce.

Peter Diener; Brajesh Gupt; Parampreet Singh

2014-05-16T23:59:59.000Z

193

Introduction to Quantum Fields in Curved Spacetime and the Hawking Effect  

E-Print Network [OSTI]

These notes introduce the subject of quantum field theory in curved spacetime and some of its applications and the questions they raise. Topics include particle creation in time-dependent metrics, quantum origin of primordial perturbations, Hawking effect, the trans-Planckian question, and Hawking radiation on a lattice.

Ted Jacobson

2004-04-09T23:59:59.000Z

194

DARK MATTER AND DARK ENERGY AS EFFECTS OF QUANTUM GRAVITY Max I. Fomitchev1  

E-Print Network [OSTI]

DARK MATTER AND DARK ENERGY AS EFFECTS OF QUANTUM GRAVITY Max I. Fomitchev1 Submitted March 12th of high matter density expected in the early Universe I show that primordial inflation and dark energy (i , 2004 ABSTRACT I present a theory of quantum gravity based on the principle of gravitational energy

Giles, C. Lee

195

Novel Atomic Coherence and Interference Effects in Quantum Optics and Atomic Physics  

E-Print Network [OSTI]

It is well known that the optical properties of multi-level atomic and molecular system can be controlled and manipulated efficiently using quantum coherence and interference, which has led to many new effects in quantum optics for e.g. lasing...

Jha, Pankaj

2012-10-19T23:59:59.000Z

196

Acceleration of positrons by a relativistic electron beam in the presence of quantum effects  

SciTech Connect (OSTI)

Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.

Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)] [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Aki, H.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)] [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)

2013-09-15T23:59:59.000Z

197

Environment-Induced Effects on Quantum Chaos: Decoherence, Delocalization and Irreversibility  

E-Print Network [OSTI]

Decoherence in quantum systems which are classically chaotic is studied. It is well-known that a classically chaotic system when quantized loses many prominent chaotic traits. We show that interaction of the quantum system with an environment can under general circumstances quickly diminish quantum coherence and reenact some characteristic classical chaotic behavior. We use the Feynman-Vernon influence functional formalism to study the effect of an ohmic environment at high temperature on two classically-chaotic systems: The linear Arnold cat map (QCM) and the nonlinear quantum kicked rotor (QKR). Features of quantum chaos such as recurrence in QCM and diffusion suppression leading to localization in QKR are destroyed in a short time due to environment-induced decoherence. Decoherence also undermines localization and induces an apparent transition from reversible to irreversible dynamics in quantum chaotic systems.

B. L. Hu; K. Shiokawa

1995-01-13T23:59:59.000Z

198

All-Optical Switching Using the Quantum Zeno Effect and Two-Photon Absorption  

E-Print Network [OSTI]

We have previously shown that the quantum Zeno effect can be used to implement quantum logic gates for quantum computing applications, where the Zeno effect was produced using a strong two-photon absorbing medium. Here we show that the Zeno effect can also be used to implement classical logic gates whose inputs and outputs are high-intensity fields (coherent states). The operation of the devices can be understood using a quasi-static analysis, and their switching times are calculated using a dynamic approach. The two-photon absorption coefficient of rubidium vapor is shown to allow operation of these devices at relatively low power levels.

B. C. Jacobs; J. D. Franson

2009-05-08T23:59:59.000Z

199

Interaction effects and quantum phase transitions in topological insulators  

SciTech Connect (OSTI)

We study strong correlation effects in topological insulators via the Lanczos algorithm, which we utilize to calculate the exact many-particle ground-state wave function and its topological properties. We analyze the simple, noninteracting Haldane model on a honeycomb lattice with known topological properties and demonstrate that these properties are already evident in small clusters. Next, we consider interacting fermions by introducing repulsive nearest-neighbor interactions. A first-order quantum phase transition was discovered at finite interaction strength between the topological band insulator and a topologically trivial Mott insulating phase by use of the fidelity metric and the charge-density-wave structure factor. We construct the phase diagram at T=0 as a function of the interaction strength and the complex phase for the next-nearest-neighbor hoppings. Finally, we consider the Haldane model with interacting hard-core bosons, where no evidence for a topological phase is observed. An important general conclusion of our work is that despite the intrinsic nonlocality of topological phases their key topological properties manifest themselves already in small systems and therefore can be studied numerically via exact diagonalization and observed experimentally, e.g., with trapped ions and cold atoms in optical lattices.

Varney, Christopher N. [Department of Physics, Georgetown University, Washington, DC 20057 (United States); Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Sun Kai; Galitski, Victor [Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Rigol, Marcos [Department of Physics, Georgetown University, Washington, DC 20057 (United States)

2010-09-15T23:59:59.000Z

200

Quantum-mechanical description of Lense-Thirring effect for relativistic scalar particles  

E-Print Network [OSTI]

Exact expression for the Foldy-Wouthuysen Hamiltonian of scalar particles is used for a quantum-mechanical description of the relativistic Lense-Thirring effect. The exact evolution of the angular momentum operator in the Kerr field approximated by a spatially isotropic metric is found. The quantum-mechanical description of the full Lense-Thirring effect based on the Laplace-Runge-Lenz vector is given in the nonrelativistic and weak-field approximation. Relativistic quantum-mechanical equations for the velocity and acceleration operators are obtained. The equation for the acceleration defines the Coriolis-like and centrifugal-like accelerations and presents the quantum-mechanical description of the frame-dragging effect.

Alexander J. Silenko

2014-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Bing Concert Hall, Under Construction  

E-Print Network [OSTI]

Manzanita Park Knight Management Center Escondido South Skilling HEPL South Green Earth Sciences Mitchell Earth of Education Fire Truck Hse. Clock Tower Owen Bolivar House Haas Center Galvez Modular Sweet Hall Bookstore Law

Prinz, Friedrich B.

202

088 MARTIN HALL CLARICE SMITH  

E-Print Network [OSTI]

GARAGE 202 088 MARTIN HALL CLARICE SMITH PERFORMING ARTS CENTER 386 LEFRAK 038 SCHOOL OF PUBLIC HEALTH PRACTICE COMPLEX SHIPLEY FIELD AT BOB "TURTLE" SMITH STADIUM 159 COMMONS 6 975 COMMONS 5 974 SUSQUEHANNA

Anlage, Steven

203

Physics and modeling of an end-Hall (gridless) ion source  

SciTech Connect (OSTI)

In an end-Hall source, an ion beam is extracted from a magnetized plasma and accelerated by the plasma electric field without grids. The principle of end-Hall sources is similar to that of Hall effect thrusters (or closed-drift thrusters), but their design is optimized for processing applications (ion beam assisted deposition or substrate cleaning) rather than propulsion. The beam divergence is larger in end-Hall ion sources, and these sources can operate at low ion energies. Although end-Hall sources are commonly used in the surface processing industry, no detailed modeling of these sources is available, and their operation is quite empirical. In this paper, a self-consistent, two-dimensional, quasineutral model of an end-Hall ion source is developed and used in order to improve the understanding of the basic physics of these plasma sources and to quantify the parameters controlling the properties of the extracted ion beam.

Oudini, N. [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Hagelaar, G. J. M.; Boeuf, J.-P.; Garrrigues, L. [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d'Energie), 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France)

2011-04-01T23:59:59.000Z

204

Effects of quantum space time foam in the neutrino sector  

E-Print Network [OSTI]

We discuss violations of CPT and quantum mechanics due to interactions of neutrinos with space-time quantum foam. Neutrinoless double beta decay and oscillations of neutrinos from astrophysical sources (supernovae, active galactic nuclei) are analysed. It is found that the propagation distance is the crucial quantity entering any bounds on EHNS parameters. Thus, while the bounds from neutrinoless double beta decay are not significant, the data of the supernova 1987a imply a bound being several orders of magnitude more stringent than the ones known from the literature. Even more stringent limits may be obtained from the investigation of neutrino oscillations from active galactic nuclei sources, which have an impressive potential for the search of quantum foam interactions in the neutrino sector.

H. V. Klapdor-Kleingrothaus; H. Päs; U. Sarkar

2000-07-05T23:59:59.000Z

205

Haaren Hall North Hall WestportNew Building BMW 54th St. Annex Getting Around  

E-Print Network [OSTI]

Haaren Hall North Hall WestportNew Building BMW 54th St. Annex Getting Around 4th Edition September . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BMW · Floor 6

Rosen, Jay

206

Real-time effective-action approach to the Anderson quantum dot  

E-Print Network [OSTI]

The non-equilibrium time evolution of an Anderson quantum dot is investigated. The quantum dot is coupled between two leads forming a chemical-potential gradient. We use Kadanoff-Baym dynamic equations within a non-perturbative resummation of the s-channel bubble chains. The effect of the resummation leads to the introduction of a frequency-dependent 4-point vertex. The tunneling to the leads is taken into account exactly. The method allows the determination of the transient as well as stationary transport through the quantum dot, and results are compared with different schemes discussed in the literature (fRG, ISPI, tDMRG and QMC).

Sexty, Denes; Pawlowski, Jan

2010-01-01T23:59:59.000Z

207

Real-time effective-action approach to the Anderson quantum dot  

E-Print Network [OSTI]

The non-equilibrium time evolution of an Anderson quantum dot is investigated. The quantum dot is coupled between two leads forming a chemical-potential gradient. We use Kadanoff-Baym dynamic equations within a non-perturbative resummation of the s-channel bubble chains. The effect of the resummation leads to the introduction of a frequency-dependent 4-point vertex. The tunneling to the leads is taken into account exactly. The method allows the determination of the transient as well as stationary transport through the quantum dot, and results are compared with different schemes discussed in the literature (fRG, ISPI, tDMRG and QMC).

Denes Sexty; Thomas Gasenzer; Jan Pawlowski

2010-12-20T23:59:59.000Z

208

Observation of the Kondo effect in a spin-3/2 hole quantum dot  

SciTech Connect (OSTI)

We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

Klochan, O.; Micolich, A. P.; Hamilton, A. R. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Trunov, K.; Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

2013-12-04T23:59:59.000Z

209

Negative differential gain in quantum dot systems: Interplay of structural properties and many-body effects  

SciTech Connect (OSTI)

The saturation behaviour of optical gain with increasing excitation density is an important factor for laser device performance. For active materials based on self-organized InGaAs/GaAs quantum dots, we study the interplay between structural properties of the quantum dots and many-body effects of excited carriers in the optical properties via a combination of tight-binding and quantum-kinetic calculations. We identify regimes where either phase-space filling or excitation-induced dephasing dominates the saturation behavior of the optical gain. The latter can lead to the emergence of a negative differential material gain.

Goldmann, E., E-mail: goldmann@itp.uni-bremen.de; Jahnke, F. [Institute for Theoretical Physics, University of Bremen, Bremen 28359 (Germany); Lorke, M.; Frauenheim, T. [Bremen Center for Computational Materials Science BCCMS, University of Bremen, Bremen 28359 (Germany)

2014-06-16T23:59:59.000Z

210

Direct Measurement of Competing Quantum Effects on the Kinetic Energy of Heavy Water upon Melting  

E-Print Network [OSTI]

Even at room temperature, quantum mechanics plays a major role in determining the quantitative behaviour of light nuclei, changing significantly the values of physical properties such as the heat capacity. However, other observables appear to be only weakly affected by nuclear quantum effects (NQEs): for instance, the melting temperatures of light and heavy water differ by less than 4 K. Recent theoretical work has attributed this to a competition between intra and inter molecular NQEs, which can be separated by computing the anisotropy of the quantum kinetic energy tensor. The principal values of this tensor change in opposite directions when ice melts, leading to a very small net quantum mechanical effect on the melting point. This paper presents the first direct experimental observation of this phenomenon, achieved by measuring the deuterium momentum distributions n(p) in heavy water and ice using Deep Inelastic Neutron Scattering (DINS), and resolving their anisotropy. Results from the experiments, supple...

Romanelli, Giovanni; Manolopoulos, David E; Pantalei, Claudia; Senesi, Roberto; Andreani, Carla

2013-01-01T23:59:59.000Z

211

hal-00130698,version1-13Feb2007 Electronic structure of epitaxial graphene layers on SiC: effect of the substrate.  

E-Print Network [OSTI]

hal-00130698,version1-13Feb2007 Electronic structure of epitaxial graphene layers on SiC: effect integer quantum Hall effects expected for isolated graphene sheets. This is the case eventhough the layer-substrate epitaxy of these films implies a strong interface bond that should induce perturbations in the graphene

Paris-Sud XI, Université de

212

Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs  

SciTech Connect (OSTI)

Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

Hendra, P. I. B., E-mail: ib.hendra@gmail.com; Rahayu, F., E-mail: ib.hendra@gmail.com; Darma, Y., E-mail: ib.hendra@gmail.com [Physical Vapor Deposition Laboratory, Physics of Material Electronics Research, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24T23:59:59.000Z

213

Correlation between the extraordinary Hall constant and electrical resistivity minima in Co-rich metallic glasses  

E-Print Network [OSTI]

The Hall effect has been studied in some Co-rich ferromagnetic metallic glasses which show resistivity (rho) minima at low temperatures. It is found that the extraordinary Hall constant (R-s) shows a corresponding minimum. The scaling relation R...

Majumdar, AK; Khatua, PK; Rathnayaka, KDD; Naugle, Donald G.

2004-01-01T23:59:59.000Z

214

Gravitational Effects of Quantum Fields in the Interior of a Cylindrical Black Hole  

E-Print Network [OSTI]

The gravitational back-reaction is calculated for the conformally invariant scalar field within a black cosmic string interior with cosmological constant. Using the perturbed metric, the gravitational effects of the quantum field are calculated. It is found that the perturbations initially strengthen the singularity. This effect is similar to the case of spherical symmetry (without cosmological constant). This indicates that the behaviour of quantum effects may be universal and not dependent on the geometry of the spacetime nor the presence of a non-zero cosmological constant.

A. DeBenedictis

1998-11-18T23:59:59.000Z

215

Quantum theory of bilayer quantum Hall smectics Emiliano Papa,1  

E-Print Network [OSTI]

of charge-density and position along each stripe edge. The soft modes associated with the broken symmetries spontaneous interlayer phase coherence and a sizable charge gap even at relatively large layer separations in very high mobility bilayer systems at dilution refrigerator temperatures as a function of layer

216

Black hole fireworks: quantum-gravity effects outside the horizon spark black to white hole tunneling  

E-Print Network [OSTI]

We show that there is a classical metric satisfying the Einstein equations outside a finite spacetime region where matter collapses into a black hole and then emerges from a white hole. We compute this metric explicitly. We show how quantum theory determines the (long) time for the process to happen. A black hole can thus quantum-tunnel into a white hole. For this to happen, quantum gravity should affect the metric also in a small region outside the horizon: we show that contrary to what is commonly assumed, this is not forbidden by causality or by the semiclassical approximation, because quantum effects can pile up over a long time. This scenario alters radically the discussion on the black hole information puzzle.

Hal M. Haggard; Carlo Rovelli

2014-07-06T23:59:59.000Z

217

Geometrical effects on energy transfer in disordered open quantum systems  

E-Print Network [OSTI]

We explore various design principles for efficient excitation energy transport in complex quantum systems. We investigate energy transfer efficiency in randomly disordered geometries consisting of up to 20 chromophores to explore spatial and spectral properties of small natural/artificial Light-Harvesting Complexes (LHC). We find significant statistical correlations among highly efficient random structures with respect to ground state properties, excitonic energy gaps, multichromophoric spatial connectivity, and path strengths. These correlations can even exist beyond the optimal regime of environment-assisted quantum transport. For random configurations embedded in spatial dimensions of 30 A and 50 A, we observe that the transport efficiency saturates to its maximum value if the systems contain 7 and 14 chromophores respectively. Remarkably, these optimum values coincide with the number of chlorophylls in (Fenna-Matthews-Olson) FMO protein complex and LHC II monomers, respectively, suggesting a potential natural optimization with respect to chromophoric density.

M. Mohseni; A. Shabani; S. Lloyd; Y. Omar; H. Rabitz

2012-12-31T23:59:59.000Z

218

Correlation effects on topological insulator  

E-Print Network [OSTI]

The strong correlation effects on topological insulator are studied in a two-sublattice system with an onsite single-particle energy difference $\\Delta$ between two sublattices. At $\\Delta=0$, increasing the onsite interaction strength $U$ drives the transition from the quantum spin Hall insulating state to the non-topological antiferromagnetic Mott-insulating (AFMI) state. When $\\Delta$ is larger than a certain value, a topologically trivial band insulator or AFMI at small values of $U$ may change into a quantum anomalous Hall state with antiferromagnetic ordering at intermediate values of $U$. Further increasing $U$ drives the system back into the topologically trivial state of AFMI. The corresponding phenomena is observable in the solid state and cold atom systems. We also propose a scheme to realize and detect these effects in cold atom systems.

Xiong-Jun Liu; Yang Liu; Xin Liu

2010-11-24T23:59:59.000Z

219

A molecular dynamics study of nuclear quantum effect on the diffusion of hydrogen in condensed phase  

SciTech Connect (OSTI)

In this paper, the quantum effect of hydrogen molecule on its diffusivity is analyzed using Molecular Dynamics (MD) method. The path integral centroid MD (CMD) method is applied for the reproduction method of time evolution of the molecules. The diffusion coefficient of liquid hydrogen is calculated using the Green-Kubo method. The simulation is performed at wide temperature region and the temperature dependence of the quantum effect of hydrogen molecule is addressed. The calculation results are compared with those of classical MD results. As a result, it is confirmed that the diffusivity of hydrogen molecule is changed depending on temperature by the quantum effect. It is clarified that this result can be explained that the dominant factor by quantum effect on the diffusivity of hydrogen changes from the swollening the potential to the shallowing the potential well around 30 K. Moreover, it is found that this tendency is related to the temperature dependency of the ratio of the quantum kinetic energy and classical kinetic energy.

Nagashima, Hiroki; Tokumasu, Takashi [Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi (Japan); Tsuda, Shin-ichi [Shinshu University, 77-7 Minamibori, Nagano, Nagano (Japan); Tsuboi, Nobuyuki [Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu, Fukuoka (Japan); Koshi, Mitsuo [Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama, Kanagawa (Japan); Hayashie, A. Koichi [AoyamaGakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa (Japan)

2014-10-06T23:59:59.000Z

220

Hybrid skew scattering regime of the anomalous Hall effect in Rashba systems: Unifying Keldysh, Boltzmann, and Kubo formalisms RID B-3617-2008  

E-Print Network [OSTI]

. Smit, Physica #1;Amsterdam#2; 21, 877 #1;1955#2;. 3 L. Berger, Phys. Rev. B 2, 4559 #1;1970#2;. 4 P. Nozieres and C. Lewiner, J. Phys. #1;Paris#2; 34, 901 #1;1973#2;. 5 V. K. Dugaev, P. Bruno, M. Taillefumier, B. Canals, and C. Lacroix, Phys. Rev. B...-Particle Physics #1;Plenum, New York, 1990#2;. 16 H.-A. Engel, B. I. Halperin, and E. I. Rashba, Phys. Rev. Lett. 95, 166605 #1;2005#2;. 17 A. Cr?pieux and P. Bruno, Phys. Rev. B 64, 014416 #1;2001#2;. FIG. 2. #1;Color online#2; The anomalous Hall conductivity...

Kovalev, Alexey A.; Vyborny, Karel; Sinova, Jairo.

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

The Monty Hall Problem Afra Zomorodian  

E-Print Network [OSTI]

The Monty Hall Problem's origin is from the TV show, "Let's Make A Deal" hosted by Monty Hall. The statement curtain but before the curtain is lifted, the emcee lifts one of the other curtains, revealing an empty

Zomorodian, Afra

222

The Monty Hall Problem Afra Zomorodian  

E-Print Network [OSTI]

The Monty Hall Problem's origin is from the TV show, ``Let's Make A Deal'' hosted by Monty Hall have picked one curtain but before the curtain is lifted, the emcee lifts one of the other curtains

Zomorodian, Afra

223

City Hall plazas : they're different  

E-Print Network [OSTI]

This essay explores the form, goals, and ideals behind city hall plazas by asking the questions: What is the difference between a city hall plaza and any other urban plaza? What are the uses intended by the city in the ...

Hall, Kristen E. (Kristen Elizabeth)

2008-01-01T23:59:59.000Z

224

UBC Video Collection / Raymond J. Hall (collector)  

E-Print Network [OSTI]

UBC Video Collection / Raymond J. Hall (collector) Compiled by Christopher Hives (2011) University / Physical Description Collector's Biographical Sketch Custodial History Scope and Content Item List (collector). - 1992-2002. 30 video recordings. Collector's Biographical Sketch Raymond Hall came to Vancouver

Handy, Todd C.

225

Effect of phonon confinement on lattice thermal conductivity of lead Telluride quantum well structure  

SciTech Connect (OSTI)

The paper examines the effect of spatial confinement of acoustic phonons on average group velocity and consequently the lattice thermal conductivity of a free-standing PbTe quantum well structure and their temperature dependence. The average group velocity at 100 Å decreases 30% to the bulk value and falls more rapidly on reducing the width of quantum well. Moreover, the lattice thermal conductivity of 100 Å wide PbTe quantum well with value of 0.60 W/mK shows considerable decrease of 70% compared to it’s bulk value. It is observed that the effect of reduction in well width is less pronounce as temperature increases. This appears mainly due to dominance of umklapp processes over the confinement effects.

Tripathi, Madhvendra Nath, E-mail: ommadhav27@gmail.com [Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur-495009, Chhattisgarh (India)

2014-04-24T23:59:59.000Z

226

Effect of laser phase noise on the fidelity of optomechanical quantum memory  

E-Print Network [OSTI]

Optomechanical and electromechanical cavities have been widely used in quantum memories and quantum transducers. We investigate theoretically the robustness of opto(electro)-mechanical quantum memories against the noise of the control laser. By solving the Langevin equations and using the covariance matrix formalism in the presence of laser noise effect, the storing fidelity of Gaussian states is obtained. It is shown that, the destructive effect of phase noise is more significant in higher values of coupling laser amplitude and optomechanical coupling strength G. However by further increasing of G, the interaction time between photons and phonons decreases below the coherence time of laser frequency noise and the destructive effect of laser phase noise on the storing fidelity decreases.

Farnaz Farman; Alireza Bahrampour

2015-01-18T23:59:59.000Z

227

General Residence Hall Information General Information  

E-Print Network [OSTI]

/dining facilities. Air Conditioning All rooms in Susan Davis Hall are equipped with window air conditioning units

Sheridan, Jennifer

228

ThompsonHall DimondLibrary  

E-Print Network [OSTI]

Congreve Hall ThompsonHall Murkland Hall DeMer Ha DimondLibrary Bounce House Bounce House 13-30 31 Durham Business Association 96A Durham: It's Where U Live 164 Ecological Advocates 14 Education Crime Investigation Association 49 Hillell 167 Horsemen's Club 29 Housing 138 Improv Anonymous 13

229

Graduate Hall Director Office of Residential Programs  

E-Print Network [OSTI]

Page 1 Graduate Hall Director Office of Residential Programs Housing Guidelines #12;Page 2 Graduate Hall Director for Residential Programs Guidelines for Residence This document is intended for the Office of Residential Programs Graduate Hall Directors (GHDs) who obtain housing on campus as part

Hone, James

230

Quantum Control by Imaging : The Zeno effect in an ultracold lattice gas  

E-Print Network [OSTI]

We demonstrate the control of quantum tunneling in an ultracold lattice gas by the measurement backaction imposed by an imaging process. A {\\em in situ} imaging technique is used to acquire repeated images of an ultracold gas confined in a shallow optical lattice. The backaction induced by these position measurements modifies the coherent quantum tunneling of atoms within the lattice. By smoothly varying the rate at which spatial information is extracted from the atomic ensemble, we observe the continuous crossover from the 'weak measurement regime' where position measurements have little influence on the tunneling dynamics, to the 'strong measurement regime' where measurement-induced localization causes a large suppression of tunneling. This suppression of coherent tunneling is a manifestation of the Quantum Zeno effect. Our study realizes an experimental demonstration of the paradigmatic Heisenberg microscope in a lattice gas and sheds light on the implications of quantum measurement on the coherent evolution of a mesoscopic quantum system. In addition, this demonstrates a powerful technique for the control of an interacting many-body quantum system via spatially resolved measurement backaction.

Y. S. Patil; S. Chakram; M. Vengalattore

2014-11-11T23:59:59.000Z

231

Equality of bulk and edge Hall conductances for continuous magnetic random Schrödinger operators  

E-Print Network [OSTI]

In this note, we prove the equality of the quantum bulk and the edge Hall conductances in mobility edges and in presence of disorder. The bulk and edge perturbations can be either of electric or magnetic nature. The edge conductance is regularized in a suitable way to enable the Fermi level to lie in a region of localized states.

Amal Taarabt

2014-03-30T23:59:59.000Z

232

Optical Kerr and Cotton-Mouton effects in atomic gases: a quantum-statistical study  

E-Print Network [OSTI]

Theory of the birefringence of the refractive index in atomic diamagnetic dilute gases in the presence of static electric (optical Kerr effect) and magnetic (Cotton-Mouton effect) fields is formulated. Quantum-statistical expressions for the second Kerr and Cotton-Mouton virial coefficients, valid both in the low and high temperature regimes, are derived. It is shown that both virial coefficients can rigorously be related to the difference of the fourth derivatives of the thermodynamic (pressure) virial coefficient with respect to the strength of the non-resonant optical fields with parallel and perpendicular polarizations and with respect to the external static (electric or magnetic) field. Semiclassical expansions of the Kerr and Cotton-Mouton coefficients are also considered, and quantum corrections up to and including the second order are derived. Calculations of the second Kerr and Cotton-Mouton virial coefficients of the helium-4 gas at various temperatures are reported. The role of the quantum-mechanic...

Skomorowski, Wojciech

2013-01-01T23:59:59.000Z

233

Effect of Quantum Confinement on Thermoelectric Properties of 2D and 1D Semiconductor Thin Films  

E-Print Network [OSTI]

Effect of Quantum Confinement on Thermoelectric Properties of 2D and 1D Semiconductor Thin Films A. Bulusu and D. G. Walker1 Interdisciplinary Program in Material Science Vanderbilt University Nashville on device characteristics of 1D and 2D thin film superlattices whose applications include thermoelectric

Walker, D. Greg

234

CHAPTER 5. QUANTUM-EFFECT AND HOT-ELECTRON DEVICES Dept. of Electrical Engineering  

E-Print Network [OSTI]

- 1 - CHAPTER 5. QUANTUM-EFFECT AND HOT-ELECTRON DEVICES S. Luryi Dept. of Electrical Engineering Devices 41 5.3.3 Real-Space Transfer Transistors (RSTT) 45 5.3.4 Resonant Hot-Electron And Bipolar Blockade 32 5.3 HOT-ELECTRON STRUCTURES 5.3.1 Hot Electrons In Semiconductors 37 5.3.2 Ballistic Injection

Luryi, Serge

235

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in  

E-Print Network [OSTI]

experiments involving biological tissues. Index Terms--Far infrared, Terahertz Heating, Breast and BrainIEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1 Modeling of Terahertz Heating Effects in real tissues causes heating as with any other electromagnetic radiation propagation. A finite element

Ganesan, Sashikumaar

236

Quantum nuclear effects on the location of hydrogen above and below the palladium (100) surface  

E-Print Network [OSTI]

and absorption of hydrogen and its isotopes. Many studies [19­22], such as low energy electron diffraction (LEED, and thus have important implications in low temperature catalytic hydrogenation reactions [23­25Quantum nuclear effects on the location of hydrogen above and below the palladium (100) surface

Alavi, Ali

237

Hybrid approach for including electronic and nuclear quantum effects in molecular dynamics simulations of hydrogen transfer  

E-Print Network [OSTI]

Hybrid approach for including electronic and nuclear quantum effects in molecular dynamics January 2001 A hybrid approach for simulating proton and hydride transfer reactions in enzymes coefficient and to investigate the real-time dynamics of reactive trajectories. This hybrid approach includes

Hammes-Schiffer, Sharon

238

Isotope Effect on Adsorbed Quantum Phases: Diffusion of H2 and D2 in Nanoporous Carbon  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

Quasielastic neutron scattering of H2 and D2 in the same nanoporous carbon at 10–40 K demonstrates extreme quantum sieving, with D2 diffusing up to 76 times faster. D2 also shows liquidlike diffusion while H2 exhibits Chudley-Elliott jump diffusion, evidence of their different relationships with the local lattice of adsorption sites due to quantum effects on intermolecular interactions. The onset of diffusion occurs at 22–25 K for H2 and 10–13 K for D2. At these temperatures, H2 and D2 have identical thermal de Broglie wavelengths that correlate with the dominant pore size.

Contescu, Cristian I.; Zhang, Hongxin; Olsen, Raina J.; Mamontov, Eugene; Morris, James R.; Gallego, Nidia C.

2013-06-01T23:59:59.000Z

239

Effect of shells on photoluminescence of aqueous CdTe quantum dots  

SciTech Connect (OSTI)

Graphical abstract: Size-tunable CdTe coated with several shells using an aqueous solution synthesis. CdTe/CdS/ZnS quantum dots exhibited high PL efficiency up to 80% which implies the promising applications for biomedical labeling. - Highlights: • CdTe quantum dots were fabricated using an aqueous synthesis. • CdS, ZnS, and CdS/ZnS shells were subsequently deposited on CdTe cores. • Outer ZnS shells provide an efficient confinement of electron and hole inside the QDs. • Inside CdS shells can reduce the strain on the QDs. • Aqueous CdTe/CdS/ZnS QDs exhibited high stability and photoluminescence efficiency of 80%. - Abstract: CdTe cores with various sizes were fabricated in aqueous solutions. Inorganic shells including CdS, ZnS, and CdS/ZnS were subsequently deposited on the cores through a similar aqueous procedure to investigate the effect of shells on the photoluminescence properties of the cores. In the case of CdTe/CdS/ZnS quantum dots, the outer ZnS shell provides an efficient confinement of electron and hole wavefunctions inside the quantum dots, while the middle CdS shell sandwiched between the CdTe core and ZnS shell can be introduced to obviously reduce the strain on the quantum dots because the lattice parameters of CdS is situated at the intermediate-level between those of CdTe and ZnS. In comparison with CdTe/ZnS core–shell quantum dots, the as-prepared water-soluble CdTe/CdS/ZnS quantum dots in our case can exhibit high photochemical stability and photoluminescence efficiency up to 80% in an aqueous solution, which implies the promising applications in the field of biomedical labeling.

Yuan, Zhimin; Yang, Ping, E-mail: mse_yangp@ujn.edu.cn

2013-07-15T23:59:59.000Z

240

How to test the gauge-invariant non-local quantum dynamics of the Aharonov-Bohm effect  

E-Print Network [OSTI]

The gauge invariant non local quantum dynamics of the Aharonov-Bohm effect can be tested experimentally by measuring the instantaneous shift of the velocity distribution occurring when the particle passes by the flux line. It is shown that in relativistic quantum theory it is possible to measure the instantaneous velocity with accuracy sufficient to detect the change of the velocity distribution. In non relativistic quantum theory the instantaneous velocity can be measured to any desired accuracy.

T. Kaufherr

2014-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Nuclear quantum effects in liquid water from path-integral simulations using an ab initio force matching approach  

E-Print Network [OSTI]

We have applied path integral simulations, in combination with new ab initio based water potentials, to investigate nuclear quantum effects in liquid water. Because direct ab initio path integral simulations are computationally expensive, a flexible water model is parameterized by force-matching to density functional theory-based molecular dynamics simulations. The resulting effective potentials provide an inexpensive replacement for direct ab inito molecular dynamics simulations and allow efficient simulation of nuclear quantum effects. Static and dynamic properties of liquid water at ambient conditions are presented and the role of nuclear quantum effects, exchange-correlation functionals and dispersion corrections are discussed in regards to reproducing the experimental properties of liquid water.

Thomas Spura; Christopher John; Scott Habershon; Thomas D. Kühne

2014-02-06T23:59:59.000Z

242

Effect of quantum dot position and background doping on the performance of quantum dot enhanced GaAs solar cells  

SciTech Connect (OSTI)

The effect of the position of InAs quantum dots (QD) within the intrinsic region of pin-GaAs solar cells is reported. Simulations suggest placing the QDs in regions of reduced recombination enables a recovery of open-circuit voltage (V{sub OC}). Devices with the QDs placed in the center and near the doped regions of a pin-GaAs solar cell were experimentally investigated. While the V{sub OC} of the emitter-shifted device was degraded, the center and base-shifted devices exhibited V{sub OC} comparable to the baseline structure. This asymmetry is attributed to background doping which modifies the recombination profile and must be considered when optimizing QD placement.

Driscoll, Kristina, E-mail: kmdsps@rit.edu; Bennett, Mitchell F.; Polly, Stephen J.; Forbes, David V.; Hubbard, Seth M., E-mail: smhsps@rit.edu [NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, New York (United States)

2014-01-13T23:59:59.000Z

243

Electron-exchange effects on the charge capture process in degenerate quantum plasmas  

SciTech Connect (OSTI)

The electron-exchange effects on the charge capture process are investigated in degenerate quantum plasmas. The Bohr-Lindhard formalism with the effective interaction potential is employed to obtain the charge capture radius, capture probability, and capture cross section as functions of the impact parameter, projectile energy, electron-exchange parameter, Fermi energy, and plasmon energy. The result shows that the electron-exchange effect enhances the charge capture radius and the charge capture cross section in semiconductor quantum plasmas. It is also found that the charge capture radius and charge capture cross section increases with an increase of the Fermi energy and, however, decreases with increasing plasmon energy. Additionally, it is found that the peak position of the charge capture cross section is receded from the collision center with an increase of the electron-exchange parameter.

Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States) [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Akbari-Moghanjoughi, M. [Azarbaijan Shahid Madani University, Faculty of Sciences, Department of Physics, 51745-406 Tabriz (Iran, Islamic Republic of) [Azarbaijan Shahid Madani University, Faculty of Sciences, Department of Physics, 51745-406 Tabriz (Iran, Islamic Republic of); International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum (Germany)

2014-03-15T23:59:59.000Z

244

Quantum field theory in a magnetic field: From quantum chromodynamics to graphene and Dirac semimetals  

E-Print Network [OSTI]

A range of quantum field theoretical phenomena driven by external magnetic fields and their applications in relativistic systems and quasirelativistic condensed matter ones, such as graphene and Dirac/Weyl semimetals, are reviewed. We start by introducing the underlying physics of the magnetic catalysis. The dimensional reduction of the low-energy dynamics of relativistic fermions in an external magnetic field is explained and its role in catalyzing spontaneous symmetry breaking is emphasized. The general theoretical consideration is supplemented by the analysis of the magnetic catalysis in quantum electrodynamics, chromodynamics and quasirelativistic models relevant for condensed matter physics. By generalizing the ideas of the magnetic catalysis to the case of nonzero density and temperature, we argue that other interesting phenomena take place. The chiral magnetic and chiral separation effects are perhaps the most interesting among them. In addition to the general discussion of the physics underlying chiral magnetic and separation effects, we also review their possible phenomenological implications in heavy-ion collisions and compact stars. We also discuss the application of the magnetic catalysis ideas for the description of the quantum Hall effect in monolayer and bilayer graphene, and conclude that the generalized magnetic catalysis, including both the magnetic catalysis condensates and the quantum Hall ferromagnetic ones, lies at the basis of this phenomenon. We also consider how an external magnetic field affects the underlying physics in a class of three-dimensional quasirelativistic condensed matter systems, Dirac semimetals. While at sufficiently low temperatures and zero density of charge carriers, such semimetals are expected to reveal the regime of the magnetic catalysis, the regime of Weyl semimetals with chiral asymmetry is realized at nonzero density...

Vladimir A. Miransky; Igor A. Shovkovy

2015-04-10T23:59:59.000Z

245

Quantum field theory in a magnetic field: From quantum chromodynamics to graphene and Dirac semimetals  

E-Print Network [OSTI]

A range of quantum field theoretical phenomena driven by external magnetic fields and their applications in relativistic systems and quasirelativistic condensed matter ones, such as graphene and Dirac/Weyl semimetals, are reviewed. We start by introducing the underlying physics of the magnetic catalysis. The dimensional reduction of the low-energy dynamics of relativistic fermions in an external magnetic field is explained and its role in catalyzing spontaneous symmetry breaking is emphasized. The general theoretical consideration is supplemented by the analysis of the magnetic catalysis in quantum electrodynamics, chromodynamics and quasirelativistic models relevant for condensed matter physics. By generalizing the ideas of the magnetic catalysis to the case of nonzero density and temperature, we argue that other interesting phenomena take place. The chiral magnetic and chiral separation effects are perhaps the most interesting among them. In addition to the general discussion of the physics underlying chiral magnetic and separation effects, we also review their possible phenomenological implications in heavy-ion collisions and compact stars. We also discuss the application of the magnetic catalysis ideas for the description of the quantum Hall effect in monolayer and bilayer graphene, and conclude that the generalized magnetic catalysis, including both the magnetic catalysis condensates and the quantum Hall ferromagnetic ones, lies at the basis of this phenomenon. We also consider how an external magnetic field affects the underlying physics in a class of three-dimensional quasirelativistic condensed matter systems, Dirac semimetals. While at sufficiently low temperatures and zero density of charge carriers, such semimetals are expected to reveal the regime of the magnetic catalysis, the regime of Weyl semimetals with chiral asymmetry is realized at nonzero density...

Vladimir A. Miransky; Igor A. Shovkovy

2015-03-02T23:59:59.000Z

246

A model of the quantum-classical and mind-brain connections, and of the role of the quantum Zeno effect in the physical implementation of conscious intent  

E-Print Network [OSTI]

A simple exactly solvable model is given of the dynamical coupling between a person's classically described perceptions and that person's quantum mechanically described brain. The model is based jointly upon von Neumann's theory of measurement and the empirical findings of close connections between conscious intentions and synchronous oscillations in well separated parts of the brain. A quantum-Zeno-effect-based mechanism is described that allows conscious intentions to influence brain activity in a functionally appropriate way. The robustness of this mechanism in the face of environmental decoherence effects is emphasized.

Henry P. Stapp

2008-03-11T23:59:59.000Z

247

Effects of time ordering in quantum nonlinear optics  

E-Print Network [OSTI]

We study time ordering corrections to the description of spontaneous parametric down-conversion (SPDC), four wave mixing (SFWM) and frequency conversion (FC) using the Magnus expansion. Analytic approximations to the evolution operator that are unitary are obtained. They are Gaussian preserving, and allow us to understand order-by-order the effects of time ordering. We show that the corrections due to time ordering vanish exactly if the phase matching function is sufficiently broad. The calculation of the effects of time ordering on the joint spectral amplitude of the photons generated in spontaneous SPDC and SFWM are reduced to quadrature.

Nicolás Quesada; J. E. Sipe

2014-07-25T23:59:59.000Z

248

Building Green in Greensburg: City Hall Building  

Office of Energy Efficiency and Renewable Energy (EERE)

This poster highlights energy efficiency, renewable energy, and sustainable features of the high-performing City Hall building in Greensburg, Kansas.

249

Hall Magnetohydrodynamics of weakly-ionized plasma  

E-Print Network [OSTI]

We show that the Hall scale in a weakly ionized plasma depends on the fractional ionization of the medium and, Hall MHD description becomes important whenever the ion-neutral collision frequency is comparable to the ion-gyration frequency, or, the ion-neutral collisional mean free path is smaller than the ion gyro-radius. Wave properties of a weakly-ionized plasma also depends on the fractional ionization and plasma Hall parameters, and whistler mode is the most dominant mode in such a medium. Thus Hall MHD description will be important in astrophysical disks, dark molecular clouds, neutron star crusts, and, solar and planetary atmosphere.

B. P. Pandey; Mark Wardle

2006-08-02T23:59:59.000Z

250

The Aharonov-Bohm effect: A quantum or a relativistic phenomenon?  

E-Print Network [OSTI]

The Aharonov-Bohm effect is considered by most authors as a quantum effect, but a generally accepted explanation does not seem to be available. The phenomenon is studied here under the assumption that hypothetical electric dipole distributions configured by moving charges in the solenoid act on the electrons as test particles. The relative motions of the interacting charged particles introduce relativistic time dilations. The massless dipoles are postulated as part of an impact model that has recently been proposed to account for the far-reaching electrostatic forces between charged particles described by Coulomb's law. The model provides a quantitative explanation of the Aharonov-Bohm effect.

K. Wilhelm; B. N. Dwivedi

2014-08-23T23:59:59.000Z

251

Experimental demonstration of interaction-free all-optical switching via the quantum Zeno effect  

E-Print Network [OSTI]

We experimentally demonstrate all-optical interaction-free switching using the quantum Zeno effect, achieving a high contrast of 35:1. The experimental data matches a zero-parameter theoretical model for several different regimes of operation, indicating a good understanding of the switch's characteristics. We also discuss extensions of this work that will allow for significantly improved performance, and the integration of this technology onto chip-scale devices.

Kevin T. McCusker; Yu-Ping Huang; Abijith Kowligy; Prem Kumar

2013-01-31T23:59:59.000Z

252

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 35, NO. 1, JANUARY 1999 1 Effect of the Solvent Viscosity on the  

E-Print Network [OSTI]

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 35, NO. 1, JANUARY 1999 1 Effect of the Solvent Viscosity HTECH-LG951494. The authors are with the Departamento de ´Optica, Facultad de Ciencias F

Rey Juan Carlos, Universidad

253

Bystander effect and adaptive response in C3H 10TK cells S. A. MITCHELL, S. A. MARINO, D. J. BRENNER and E. J. HALL  

E-Print Network [OSTI]

the bystander effect, adaptive response, genomic instabil- ity and low-dose hyper-radiosensitivity. These pheno

254

Quantum Gravitational Effects on Massive Fermions during Inflation I  

E-Print Network [OSTI]

We compute the one loop graviton contribution to the self-energy of a very light fermion on a locally de Sitter background. This result can be used to study the effect that a small mass has on the propagation of fermions through the sea of infrared gravitons generated by inflation. We employ dimensional regularization and obtain a fully renormalized result by absorbing all divergences with BPHZ counterterms. An interesting technical aspect of this computation is the need for two noninvariant counterterms owing to the breaking of de Sitter invariance by our gauge condition.

S. P. Miao

2012-12-03T23:59:59.000Z

255

Town Hall with Secretary Moniz and Deputy Secretary Sherwood...  

Broader source: Energy.gov (indexed) [DOE]

Town Hall with Secretary Moniz and Deputy Secretary Sherwood-Randall Town Hall with Secretary Moniz and Deputy Secretary Sherwood-Randall Please join Secretary of Energy Ernest...

256

Building America Top Innovations Hall of Fame Profile - Building...  

Energy Savers [EERE]

Top Innovations Hall of Fame Profile - Building America's Top Innovations Propel the Home Building Industry toward Higher Performance Building America Top Innovations Hall of Fame...

257

ARM - Welcome to Study Hall  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformationCenterResearch Highlights Media ContactgovEducationWelcome to Study Hall

258

Town Hall with Secretary Moniz  

ScienceCinema (OSTI)

In a town hall meeting with Department staff, Energy Secretary Ernest Moniz spoke about his plans for a reorganization of the Energy Department?s management structure. The plans will help better achieve the Department?s key priorities and those of the President, including implementing the President?s Climate Action Plan, ?all of the above? energy strategy and nuclear security agenda. After his remarks, Moniz, joined by Deputy Secretary Dan Poneman, took questions from the audience in the Forrestal Auditorium as well as email questions from other Department locations.

Energy Secretary Ernest Moniz; Deputy Secretary of Energy Daniel Poneman

2013-07-25T23:59:59.000Z

259

Portland State University Shattuck Hall  

High Performance Buildings Database

Portland, OR Portland State's Shattuck hall was originally constructed as an elementary school in 1915. In 2007 the university undertook extensive renovations of the building to bring it up to current seismic requirements. In addition to structural improvements, the design team was able to upgraded the building's aging mechanical and electrical systems, upgrade plumbing, and restore the large light wells that bring daylight into the U-shaped building. The resulting building houses Portland State's Architecture department, where students are able to learn from the exposed building systems.

260

Experimental Hall A | Jefferson Lab  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI Home It isGasERP Submit anHall A This photo

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Experimental Hall B | Jefferson Lab  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI Home It isGasERP Submit anHall A This

262

Experimental Hall C | Jefferson Lab  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI Home It isGasERP Submit anHall A

263

Experimental Hall D | Jefferson Lab  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI Home It isGasERP Submit anHall AHall D

264

Micromagnetic study of auto-oscillation modes in spin-Hall nano-oscillators  

SciTech Connect (OSTI)

We present a numerical study of magnetization dynamics in a recently introduced spin torque nano-oscillator, whose operational principle relies on the spin-Hall effect—spin-Hall nano-oscillators. Our numerical results show good agreement with the experimentally observed behaviors and provide detailed information about the features of the primary auto-oscillation mode observed in the experiments. They also clarify the physical nature of the secondary auto-oscillation mode, which was experimentally observed under certain conditions only.

Ulrichs, H., E-mail: henning.ulrichs@uni-muenster.de; Demidov, V. E.; Demokritov, S. O. [Department of Physics and Center for Nonlinear Science, University of Münster, Corrensstraße 2-4, 48149 Münster (Germany)

2014-01-27T23:59:59.000Z

265

UTEPBioinformaticsProgram Bell Hall, Room 138  

E-Print Network [OSTI]

UTEPBioinformaticsProgram Bell Hall, Room 138 The University of Texas at El Paso El Paso, TX 79968:www.bioinformatics.utep.edu UTEPBioinformatics BellHall,Room138 TheUniversityofTexasatElPaso 500W.UniversityAvenue ElPaso,TX79968 and Student Fitness Center with its two swimming pools underline the University's commitment to provide

Fuentes, Olac

266

Analysis of Effectiveness of Lyapunov Control for Non-generic Quantum States  

E-Print Network [OSTI]

A Lyapunov-based control design for natural trajectory-tracking problems is analyzed for quantum states where the analysis in the generic case is not applicable. Using dynamical systems tools we show almost global asymptotic stability for stationary target states subject to certain conditions on the Hamiltonians, and discuss effectiveness of the design when these conditions are not satisfied. For pseudo-pure target states the effectiveness of the design is studied further for both stationary and non-stationary states using alternative tools.

Xiaoting Wang; Sonia Schirmer

2009-10-01T23:59:59.000Z

267

Effect of feedback on the control of a two-level dissipative quantum system  

E-Print Network [OSTI]

We show that it is possible to modify the stationary state by a feedback control in a two-level dissipative quantum system. Based on the geometric control theory, we also analyze the effect of the feedback on the time-optimal control in the dissipative system governed by the Lindblad master equation. These effects are reflected in the function $\\Delta_A(\\vec{x})$ and $\\Delta_B(\\vec{x})$ that characterize the optimal trajectories, as well as the switching function $\\Phi(t)$ and $\\theta(t),$ which characterize the switching point in time for the time-optimal trajectory.

L. C. Wang; X. L. Huang; X. X. Yi

2008-06-10T23:59:59.000Z

268

Scanning Hall Probe Microscopy of Magnetic Vortices inVery Underdoped yttrium-barium-copper-oxide  

SciTech Connect (OSTI)

Since their discovery by Bednorz and Mueller (1986), high-temperature cuprate superconductors have been the subject of intense experimental research and theoretical work. Despite this large-scale effort, agreement on the mechanism of high-T{sub c} has not been reached. Many theories make their strongest predictions for underdoped superconductors with very low superfluid density n{sub s}/m*. For this dissertation I implemented a scanning Hall probe microscope and used it to study magnetic vortices in newly available single crystals of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} (Liang et al. 1998, 2002). These studies have disproved a promising theory of spin-charge separation, measured the apparent vortex size (an upper bound on the penetration depth {lambda}{sub ab}), and revealed an intriguing phenomenon of ''split'' vortices. Scanning Hall probe microscopy is a non-invasive and direct method for magnetic field imaging. It is one of the few techniques capable of submicron spatial resolution coupled with sub-{Phi}{sub 0} (flux quantum) sensitivity, and it operates over a wide temperature range. Chapter 2 introduces the variable temperature scanning microscope and discusses the scanning Hall probe set-up and scanner characterizations. Chapter 3 details my fabrication of submicron GaAs/AlGaAs Hall probes and discusses noise studies for a range of probe sizes, which suggest that sub-100 nm probes could be made without compromising flux sensitivity. The subsequent chapters detail scanning Hall probe (and SQUID) microscopy studies of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} crystals with T{sub c} {le} 15 K. Chapter 4 describes two experimental tests for visons, essential excitations of a spin-charge separation theory proposed by Senthil and Fisher (2000, 2001b). We searched for predicted hc/e vortices (Wynn et al. 2001) and a vortex memory effect (Bonn et al. 2001) with null results, placing upper bounds on the vison energy inconsistent with the theory. Chapter 5 discusses imaging of isolated vortices as a function of T{sub c}. Vortex images were fit with theoretical magnetic field profiles in order to extract the apparent vortex size. The data for the lowest T{sub c}'s (5 and 6.5 K) show some inhomogeneity and suggest that {lambda}{sub ab} might be larger than predicted by the T{sub c} {proportional_to} n{sub s}(0)/m* relation first suggested by results of Uemura et al. (1989) for underdoped cuprates. Finally, Chapter 6 examines observations of apparent ''partial vortices'' in the crystals. My studies of these features indicate that they are likely split pancake vortex stacks. Qualitatively, these split stacks reveal information about pinning and anisotropy in the samples. Collectively these magnetic imaging studies deepen our knowledge of cuprate superconductivity, especially in the important regime of low superfluid density.

Guikema, Janice Wynn; /SLAC, SSRL

2005-12-02T23:59:59.000Z

269

Nuclear quantum effects in water exchange around lithium and fluoride ions  

E-Print Network [OSTI]

We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reaction...

Wilkins, David M; Dang, Liem X

2015-01-01T23:59:59.000Z

270

Effective Field Theory for the Quantum Electrodynamics of a Graphene Wire  

E-Print Network [OSTI]

We study the low-energy quantum electrodynamics of electrons and holes, in a thin graphene wire. We develop an effective field theory (EFT) based on an expansion in p/p_T, where p_T is the typical momentum of electrons and holes in the transverse direction, while p are the momenta in the longitudinal direction. We show that, to the lowest-order in (p/p_T), our EFT theory is formally equivalent to the exactly solvable Schwinger model. By exploiting such an analogy, we find that the ground state of the quantum wire contains a condensate of electron-hole pairs. The excitation spectrum is saturated by electron-hole collective bound-states, and we calculate the dispersion law of such modes. We also compute the DC conductivity per unit length at zero chemical potential and find g_s =e^2/h, where g_s=4 is the degeneracy factor.

P. Faccioli; E. Lipparini

2009-06-30T23:59:59.000Z

271

Thermal vibration of a rectangular single-layered graphene sheet with quantum effects  

SciTech Connect (OSTI)

The thermal vibration of a rectangular single-layered graphene sheet is investigated by using a rectangular nonlocal elastic plate model with quantum effects taken into account when the law of energy equipartition is unreliable. The relation between the temperature and the Root of Mean Squared (RMS) amplitude of vibration at any point of the rectangular single-layered graphene sheet in simply supported case is derived first from the rectangular nonlocal elastic plate model with the strain gradient of the second order taken into consideration so as to characterize the effect of microstructure of the graphene sheet. Then, the RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet simply supported on an elastic foundation is derived. The study shows that the RMS amplitude of the rectangular single-layered graphene sheet predicted from the quantum theory is lower than that predicted from the law of energy equipartition. The maximal relative difference of RMS amplitude of thermal vibration appears at the sheet corners. The microstructure of the graphene sheet has a little effect on the thermal vibrations of lower modes, but exhibits an obvious effect on the thermal vibrations of higher modes. The quantum effect is more important for the thermal vibration of higher modes in the case of smaller sides and lower temperature. The relative difference of maximal RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet decreases monotonically with an increase of temperature. The absolute difference of maximal RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet increases slowly with the rising of Winkler foundation modulus.

Wang, Lifeng, E-mail: walfe@nuaa.edu.cn; Hu, Haiyan [State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, 210016 Nanjing (China)

2014-06-21T23:59:59.000Z

272

Effect of phase noise on quantum correlations in Bose-Josephson junctions  

SciTech Connect (OSTI)

In a two-mode Bose-Josephson junction the dynamics induced by a sudden quench of the tunnel amplitude leads to the periodic formation of entangled states. For instance, squeezed states are formed at short times and macroscopic superpositions of phase states at later times. In atom interferometry, the two modes of the junction play the role of the two arms of a Mach-Zehnder interferometer; use of multiparticle entangled states allows the enhancement of phase sensitivity with respect to that obtained from uncorrelated atoms. Decoherence due to the presence of noise degrades quantum correlations between atoms, thus reducing phase sensitivity. We consider decoherence due to stochastic fluctuations of the energies of the two modes of the junction. We analyze its effect on squeezed states and macroscopic superpositions and calculate the squeezing parameter and the quantum Fisher information during the quenched dynamics. The latter quantity measures the amount of quantum correlations useful in interferometry. For moderate noise intensities, we show that it increases on time scales beyond the squeezing regime. This suggests multicomponent superpositions of phase states as interesting candidates for high-precision atom interferometry.

Ferrini, G.; Minguzzi, A.; Hekking, F. W. J. [Universite Grenoble 1 and CNRS, Laboratoire de Physique et Modelisation des Milieux Condenses UMR5493, B.P. 166, F-38042 Grenoble (France); Spehner, D. [Universite Grenoble 1 and CNRS, Laboratoire de Physique et Modelisation des Milieux Condenses UMR5493, B.P. 166, F-38042 Grenoble (France); Universite Grenoble 1 and CNRS, Institut Fourier UMR5582, B.P. 74, F-38402 Saint Martin d'Heres (France)

2011-10-15T23:59:59.000Z

273

37A-Acad. Advising 62-Adams Hall  

E-Print Network [OSTI]

Gym 51-Still Hall 08-Stevenson Towers S 09-Stevenson Towers N Key Offices 61- Admissions--Williston 48 & Dining Services-Nept. 61-International Students-Williston 61-Registration & Records-Williston 62-Testing-Williston Hall 57-Wirtz Hall 27-Zulaug Hall Student Center #12;

Karonis, Nicholas T.

274

Towards a graphene-based quantum impedance standard  

SciTech Connect (OSTI)

Precision measurements of the quantum Hall resistance with alternating current (ac) in the kHz range were performed on epitaxial graphene in order to assess its suitability as a quantum standard of impedance. The quantum Hall plateaus measured with alternating current were found to be flat within one part in 10{sup 7}. This is much better than for plain GaAs quantum Hall devices and shows that the magnetic-flux-dependent capacitive ac losses of the graphene device are less critical. The observed frequency dependence of about ?8?×?10{sup ?8}/kHz is comparable in absolute value to the positive frequency dependence of plain GaAs devices, but the negative sign is attributed to stray capacitances which we believe can be minimized by a careful design of the graphene device. Further improvements thus may lead to a simpler and more user-friendly quantum standard for both resistance and impedance.

Kalmbach, C.-C.; Schurr, J., E-mail: juergen.schurr@ptb.de; Ahlers, F. J.; Müller, A. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany); Novikov, S.; Lebedeva, N. [Department of Micro- and Nanosciences, Aalto University, Micronova, Tietotie 3, 02150 Espoo (Finland); Satrapinski, A. [MIKES, Tekniikantie 1, P.O. Box, 02151 Espoo (Finland)

2014-08-18T23:59:59.000Z

275

Intermittency in Hall-magnetohydrodynamics with a strong guide field  

SciTech Connect (OSTI)

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling.

Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Buenos Aires 1428 (Argentina)] [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Buenos Aires 1428 (Argentina); Mininni, P. D. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Buenos Aires 1428 (Argentina) [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Buenos Aires 1428 (Argentina); National Center for Atmospheric Research, P.O. Box 3000, Boulder, Colorado 80307 (United States)

2013-05-15T23:59:59.000Z

276

Effect of high frequency modes of medium on an open quantum system  

E-Print Network [OSTI]

We present a method to calculate the real time effective propagator of a generic open quantum system, immersed in a medium using a wave function based framework. The medium is characterised by a set of harmonic oscillators having a continuous span of frequencies. This technique has been applied to the Caldeira-Leggett model showing that high frequency modes of the medium do not contribute towards decay of the population of states of the open system. In fact, they cause a Rabi type oscillation. Moreover, our wave function based approach provides an excellent alternative to conventional formalisms involving the density matrix.

Nirupam Dutta; A. K. Chaudhuri; P. K. Panigrahi

2014-09-09T23:59:59.000Z

277

Quantum transport in crystals: effective-mass theorem and k.p Hamiltonians  

E-Print Network [OSTI]

In this paper the effective mass approximation and k.p multi-band models, describing quantum evolution of electrons in a crystal lattice, are discussed. Electrons are assumed to move in both a periodic potential and a macroscopic one. The typical period of the periodic potential is assumed to be very small, while the macroscopic potential acts on a much bigger length scale. Such homogenization asymptotic is investigated by using the envelope-function decomposition of the electron wave function. If the external potential is smooth enough, the k.p and effective mass models, well known in solid-state physics, are proved to be close (in strong sense) to the exact dynamics. Moreover, the position density of the electrons is proved to converge weakly to its effective mass approximation.

Luigi Barletti; Naoufel Ben Abdallah

2014-11-14T23:59:59.000Z

278

Electron Liquids in Semiconductor Quantum Structures  

SciTech Connect (OSTI)

The groups led by Stormer and Pinczuk have focused this project on goals that seek the elucidation of novel many-particle effects that emerge in two-dimensional electron systems (2DES) as the result from fundamental quantum interactions. This experimental research is conducted under extreme conditions of temperature and magnetic field. From the materials point of view, the ultra-high mobility systems in GaAs/AlGaAs quantum structures continue to be at the forefront of this research. The newcomer materials are based on graphene, a single atomic layer of graphite. The graphene research is attracting enormous attention from many communities involved in condensed matter research. The investigated many-particle phenomena include the integer and fractional quantum Hall effect, composite fermions, and Dirac fermions, and a diverse group of electron solid and liquid crystal phases. The Stormer group performed magneto-transport experiments and far-infrared spectroscopy, while the Pinczuk group explores manifestations of such phases in optical spectra.

Aron Pinczuk

2009-05-25T23:59:59.000Z

279

Gluonic Excitations and Experimental Hall-D at Jefferson Lab  

SciTech Connect (OSTI)

A new tagged photon beam facility is being constructed in experimental Hall-D at Jefferson Lab as a part of the 12 GeV upgrade program. The 9 GeV linearly-polarized photon beam will be produced via coherent Bremsstrahlung using the CEBAF electron beam, incident on a diamond radiator. The GlueX experiment in Hall-D will use this photon beam to search for and study the pattern of gluonic excitations in the meson spectrum produced through photoproduction reactions with a liquid hydrogen target. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons, that are formed by exciting the gluonic field that couples the quarks. A subset of these hybrid mesons are predicted to have exotic quantum numbers which cannot be formed from a simple qq^- pair, and thus provide an ideal laboratory for testing QCD in the confinement regime. In these proceedings the status of the construction and installation of the GlueX detector will be presented, in addition to simulation results for some reactions of interest in hybrid meson searches.

Stevens, Justin [MIT

2014-07-01T23:59:59.000Z

280

Gluonic Excitations and Experimental Hall-D at Jefferson Lab  

E-Print Network [OSTI]

A new tagged photon beam facility is being constructed in experimental Hall-D at Jefferson Lab as a part of the 12 GeV upgrade program. The 9 GeV linearly-polarized photon beam will be produced via coherent Bremsstrahlung using the CEBAF electron beam, incident on a diamond radiator. The GlueX experiment in Hall-D will use this photon beam to search for and study the pattern of gluonic excitations in the meson spectrum produced through photoproduction reactions with a liquid hydrogen target. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons, that are formed by exciting the gluonic field that couples the quarks. A subset of these hybrid mesons are predicted to have exotic quantum numbers which cannot be formed from a simple $q\\bar{q}$ pair, and thus provide an ideal laboratory for testing QCD in the confinement regime. In these proceedings the status of the construction and installation of the GlueX detector will be presented, in addition to simulation results for some reactions of interest in hybrid meson searches.

Justin R. Stevens

2014-07-08T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Hamiltonian formulation of quantum error correction and correlated noise: Effects of syndrome extraction in the long-time limit  

E-Print Network [OSTI]

Hamiltonian formulation of quantum error correction and correlated noise: Effects of syndrome find formal expressions for the probability of a given syndrome history and the associated residual lost to the environment 12 . However, as we discuss below, QEC can very effectively slow down this loss

Baranger, Harold U.

282

The Honorable,Edward Rendell, '. City Hall  

Office of Legacy Management (LM)

'. City Hall Philadelphia, Pennsylvania 19107 Dear Mayor Rendell : ', ,' . , Secretary of Energy Hazel O',teary has announced-a new approach.to.openness in the Department of Energy...

283

Green Features Tour Duke Environment Hall Landscaping  

E-Print Network [OSTI]

and irrigation. Rainwater is collected: · From the Duke Environment Hall roof collected from the new building's roof and site paving. The building itself with a variety of water-wise edible plants, and irrigated with recycled rainwater

Reif, John H.

284

E-Print Network 3.0 - assembly hall due Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Heriot-Watt University Collection: Engineering ; Physics 2 Building Evacuation Procedures General Procedures Summary: Bonner Hall and Bell Hall. Occupants from Bell Hall...

285

Enhancement of fusion rates due to quantum effects in the particles momentum distribution in nonideal media  

E-Print Network [OSTI]

This study concerns a situation when measurements of the nonresonant cross-section of nuclear reactions appear highly dependent on the environment in which the particles interact. An appealing example discussed in the paper is the interaction of a deuteron beam with a target of deuterated metal Ta. In these experiments, the reaction cross section for d(d,p)t was shown to be orders of magnitude greater than what the conventional model predicts for the low-energy particles. In this paper we take into account the influence of quantum effects due to the Heisenberg uncertainty principle for particles in a non-ideal medium elastically interacting with the medium particles. In order to calculate the nuclear reaction rate in the non-ideal environment we apply both the Monte Carlo technique and approximate analytical calculation of the Feynman diagram using nonrelativistic kinetic Green's functions in the medium which correspond to the generalized energy and momentum distribution functions of interacting particles. We show a possibility to reduce the 12-fold integral corresponding to this diagram to a fivefold integral. This can significantly speed up the computation and control accuracy. Our calculations show that quantum effects significantly influence reaction rates such as p +7Be, 3He +4He, p +7Li, and 12C +12C. The new reaction rates may be much higher than the classical ones for the interior of the Sun and supernova stars. The possibility to observe the theoretical predictions under laboratory conditions is discussed.

N. J. Fisch; M. G. Gladush; Yu. V. Petrushevich; Piero Quarati; A. N. Starostin

2011-10-16T23:59:59.000Z

286

Scanning Hall probe microscopy of a diluted magnetic semiconductor  

SciTech Connect (OSTI)

We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga{sub 0.94}Mn{sub 0.06}As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 mum wide and fairly stable with temperature. Magnetic clusters are observed above T{sub C}, which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

Kweon, Seongsoo [Materials Science and Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Samarth, Nitin [Physics Department, Penn State University, University Park, Pennsylvania 16802 (United States); Lozanne, Alex de [Materials Science and Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)

2009-05-01T23:59:59.000Z

287

Controlling atomistic processes on Pb films via quantum size effects and lattice rotation  

SciTech Connect (OSTI)

The two main techniques used to record the data in this dissertation were Spot Profile Analysis - Low Energy Electron Diffraction (SPA-LEED) and Scanning Tunneling Microscopy (STM). A specific data analysis technique for LEED data called G(S) curves is described in depth. G(S) curves can provide a great deal of structural information about the surface; including step heights, island size, and island separation. The effects of quantum size effects (QSE) on the diffusion and critical island sizes of Pb and In on Pb #12;films are reported. Pb depositions on the 2D In phases {radical}3 and {radical}31 to see how the phases affect the Pb growth and its strong QSE are reported.

Binz, Steven

2012-06-14T23:59:59.000Z

288

Hall MHD reconnection in cometary magnetotail  

SciTech Connect (OSTI)

The fine structure of cometary tails (swirls, loops and blobs) is studied in the framework of resistive magnetic reconnection without a guide field in a dusty plasma. For a high-beta plasma ({beta} {approx} 1) consisting of electrons, ions, and immobile dust grains, a two-fluid description is used to study electromagnetic perturbations with the frequency below {omega}i, propagating at an arbitrary angle, and including the effects of Hall current. A zero-order current associated with the anti-parallel magnetic configuration may exist even in the limit of zero plasma temperature in a dusty plasma due to a symmetry breaking between electrons and ions by dust grains that yields an E-vector x B-vector current. In the perturbed state, a new linear electromagnetic mode is found in dusty plasma which is evanescent below the Rao cut-off frequency and has the characteristic wavelength comparable to the ion skin depth, which enables the reconnection at short spatial scales. The role of the dust is found to be twofold, yielding a new mode outside of the current sheet and altering the continuity conditions at its edge by an inhomogeneous Doppler shift associated with the E-vector x B-vector current.

Jovanovic, Dusan [Institute of Physics, P. O. Box 57, 11001 Belgrade (Serbia and Montenegro); Shukla, Padma Kant [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-UniverAIP confrence style sitaet Bochum, D-44780 Bochum (Germany); Morfill, Gregor [Max-Planck-Institut fuer Extraterrestrische Physik, D-85740 Garching (Germany)

2005-10-31T23:59:59.000Z

289

Exponential Decay and Fermi's Golden Rule from an Uncontrolled Quantum Zeno Effect  

E-Print Network [OSTI]

We modify the theory of the Quantum Zeno Effect to make it consistent with the postulates of quantum mechanics. This modification allows one, throughout a sequence of observations of an excited system, to address the nature of the observable and thereby to distinguish survival from non-decay, which is necessary whenever excited states are degenerate. As a consequence, one can determine which types of measurements can possibly inhibit the exponential decay of the system. We find that continuous monitoring taken as the limit of a sequence of ideal measurements will only inhibit decay in special cases, such as in well-controlled experiments. Uncontrolled monitoring of an unstable system, however, can cause exponentially decreasing non-decay probability at all times. Furthermore, calculating the decay rate for a general sequence of observations leads to a straightforward derivation of Fermi's Golden Rule, that avoids many of the conceptual difficulties normally encountered. When multiple decay channels are available, the derivation reveals how the total decay rate naturally partitions into a sum of the decay rates for the various channels, in agreement with observations. Continuous and unavoidable monitoring of an excited system by an uncontrolled environment may therefore be a mechanism by which to explain the exponential decay law.

P. W. Bryant

2014-10-14T23:59:59.000Z

290

Effect of Ligands on Characteristics of (CdSe)13 Quantum Dot  

SciTech Connect (OSTI)

The widespread applications of quantum dots (QDs) have spurred an increasing interest in the study of their coating ligands, which can not only protect the electronic structures of the central QDs, but also control their permeability through biological membranes with both size and shape. In this work, we have used density functional theory (DFT) to investigate the electronic structures of (CdSe)13 passivated by OPMe2(CH2)nMe ligands with different lengths and various numbers of branches (Me=methyl group, n = 0, 1-3). Our results show that the absorption peak in the ultraviolet-visible (UV-vis) spectra displays a clear blue-shift, on the scale of ~100 nm, upon the binding of ligands. Once the total number of ligands bound with (CdSe)13 reached a saturated number (9 or 10), no more blue-shift occurred in the absorption peak in the UV-vis spectra. On the other hand, the aliphatic chain length of ligands has a negligible effect on the optical properties of the QD core. Analyses of the bonding characteristics confirm that optical transitions are dominantly governed by the central QD core rather than the organic passivation. Interestingly, the density of states (DOS) share similar characteristics as vibrational spectra, even though there is no coordination vibration mode between the ligands and the central QD. These findings might provide insights on the material design for the passivation of quantum dots for biomedical applications.

Gao, Yang; Zhou, Bo; Kang, Seung-gu; Xin, Minsi; Yang, Ping; Dai, Xing; Wang, Zhigang; Zhou, Ruhong

2014-01-01T23:59:59.000Z

291

Local dissipation effects in two-dimensional quantum Josephson junction arrays with a magnetic field  

SciTech Connect (OSTI)

We study the quantum phase transitions in two-dimensional arrays of Josephson-couples junctions with short range Josephson couplings (given by the Josephson energy E{sub J}) and the charging energy E{sub C}. We map the problem onto the solvable quantum generalization of the spherical model that improves over the mean-field theory method. The arrays are placed on the top of a two-dimensional electron gas separated by an insulator. We include effects of the local dissipation in the presence of an external magnetic flux f={phi}/{phi}{sub 0} in square lattice for several rational fluxes f=0,(1/2),(1/3),(1/4), and (1/6). We also have examined the T=0 superconducting-insulator phase boundary as a function of a dissipation {alpha}{sub 0} for two different geometry of the lattice: square and triangular. We have found a critical value of the dissipation parameter independent on geometry of the lattice and presence magnetic field.

Polak, T.P.; Kopec, T.K. [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Strasse 38, 01187 Dresden (Germany); Institute for Low Temperatures and Structure Research, Polish Academy of Sciences, POB 1410, 50-950 Wroclaw 2 (Poland)

2005-07-01T23:59:59.000Z

292

Blinking effect and the use of quantum dots in single molecule spectroscopy  

SciTech Connect (OSTI)

Highlights: Black-Right-Pointing-Pointer It is possible to eliminate the blinking effect of a water-soluble QD. Black-Right-Pointing-Pointer We provide a direct method to study protein function and dynamics at the single level. Black-Right-Pointing-Pointer QD, potent tool for single molecule studies of biochemical and biological processes. -- Abstract: Luminescent semiconductor nanocrystals (quantum dots, QD) have unique photo-physical properties: high photostability, brightness and narrow size-tunable fluorescence spectra. Due to their unique properties, QD-based single molecule studies have become increasingly more popular during the last years. However QDs show a strong blinking effect (random and intermittent light emission), which may limit their use in single molecule fluorescence studies. QD blinking has been widely studied and some hypotheses have been done to explain this effect. Here we summarise what is known about the blinking effect in QDs, how this phenomenon may affect single molecule studies and, on the other hand, how the 'on'/'off' states can be exploited in diverse experimental settings. In addition, we present results showing that site-directed binding of QD to cysteine residues of proteins reduces the blinking effect. This option opens a new possibility of using QDs to study protein-protein interactions and dynamics by single molecule fluorescence without modifying the chemical composition of the solution or the QD surface.

Rombach-Riegraf, Verena; Oswald, Peter; Bienert, Roland; Petersen, Jan [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany)] [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany); Domingo, M.P. [Instituto de Carboquimica (CSIC), Miguel Luesma 4, 50018 Zaragoza (Spain)] [Instituto de Carboquimica (CSIC), Miguel Luesma 4, 50018 Zaragoza (Spain); Pardo, Julian [Grupo Apoptosis, Inmunidad y Cancer, Departamento Bioquimica y Biologia Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza, Zaragoza (Spain) [Grupo Apoptosis, Inmunidad y Cancer, Departamento Bioquimica y Biologia Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza, Zaragoza (Spain); Fundacion Aragon I-D (ARAID), Gobierno de Aragon, Zaragoza (Spain); Immune Effector Cells Group, Aragon Health Research Institute (IIS Aragon), Biomedical Research Centre of Aragon (CIBA) Fundacion Aragon I-D - ARAID, Gobierno de Aragon, Zaragoza (Spain); Graeber, P. [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany)] [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany); Galvez, E.M., E-mail: eva@icb.csic.es [Instituto de Carboquimica (CSIC), Miguel Luesma 4, 50018 Zaragoza (Spain); Immune Effector Cells Group, Aragon Health Research Institute (IIS Aragon), Biomedical Research Centre of Aragon (CIBA) Fundacion Aragon I-D - ARAID, Gobierno de Aragon, Zaragoza (Spain)

2013-01-04T23:59:59.000Z

293

Physics Reports 355 (2001) 235334 Quantum phase transitions and vortex dynamics in  

E-Print Network [OSTI]

Contents 1. Introduction 237 1.1. Josephson-junction arrays 237 1.2. Phase-number relation 238 1.3. Structure of the review 239 2. Quantum phase transitions 240 2.1. The model of a Josephson-junction array currents 313 4.2. The quantum Hall e ect 316 4.3. Quantum computation with Josephson junctions 317

294

Spin hall effect in paramagnetic thin films  

E-Print Network [OSTI]

the principle of Light Emitting Diode, but changed the design to a coplanar structure with two p-n junctions. A Light-Emitting Diode [27] consists of a chip of semiconductor materials doped with impurities to create a p-n junction. When the LED is forward...

Xu, Huachun

2009-05-15T23:59:59.000Z

295

Limits to Quantum Gravity Effects from Observations of TeV Flares in Active Galaxies  

E-Print Network [OSTI]

We have used data from the TeV gamma-ray flare associated with the active galaxy Markarian 421 observed on 15 May 1996 to place bounds on the possible energy-dependence of the speed of light in the context of an effective quantum gravitational energy scale. The possibility of an observable time dispersion in high energy radiation has recently received attention in the literature, with some suggestions that the relevant energy scale could be less than the Planck mass and perhaps as low as 10^16 GeV. The limits derived here indicate this energy scale to be in excess of 4x10^16 GeV at the 95% confidence level. To the best of our knowledge, this constitutes the first convincing limit on such phenomena in this energy regime.

S. D. Biller; A. C. Breslin; J. Buckley; M. Catanese; M. Carson; D. A. Carter-Lewis; M. F. Cawley; D. J. Fegan; J. Finley; J. A. Gaidos; A. M. Hillas; F. Krennrich; R. C. Lamb; R. Lessard; C. Masterson; J. E. McEnery; B. McKernan; P. Moriarty; J. Quinn; H. J. Rose; F. Samuelson; G. Sembroski; P. Skelton; T. C. Weekes

1998-10-13T23:59:59.000Z

296

The current density in quantum electrodynamics in time-dependent external potentials and the Schwinger effect  

E-Print Network [OSTI]

In the framework of quantum electrodynamics (QED) in external potentials, we introduce a method to compute the time-dependence of the expectation value of the current density for time-dependent homogeneous external electric fields. We apply it to the so-called Sauter pulse. For late times, our results agree with the asymptotic value due to electron-positron pair production. For sub-critical peak field strengths, or results agree very well with the general expression derived by Serber for the linearization in the external field. In particular, the expectation value of the current density at intermediate times can be much greater than at asymptotic times. We comment on consequences of these findings for recent proposals to test the Schwinger effect with high intensity lasers using processes at intermediate times.

Zahn, Jochen

2015-01-01T23:59:59.000Z

297

Suspending Effect on Low-Frequency Charge Noise in Graphene Quantum Dot  

E-Print Network [OSTI]

Charge noise is critical in the performance of gate-controlled quantum dots (QDs). Here we show the 1/f noise for a microscopic graphene QD is substantially larger than that for a macroscopic graphene field-effect transistor (FET), increasing linearly with temperature. To understand its origin, we suspended the graphene QD above the substrate. In contrast to large area graphene FETs, we find that a suspended graphene QD has an almost-identical noise level as an unsuspended one. Tracking noise levels around the Coulomb blockade peak as a function of gate voltage yields potential fluctuations of order 1 "{\\mu}eV", almost one order larger than in GaAs/GaAlAs QDs. Edge states rather than substrate-induced disorders, appear to dominate the 1/f noise, thus affecting the coherency of graphene nano-devices.

Xiang-Xiang Song; Hai-Ou Li; Jie You; Tian-Yi Han; Gang Cao; Tao Tu; Ming Xiao; Guang-Can Guo; Hong-Wen Jiang; Guo-Ping Guo

2014-06-16T23:59:59.000Z

298

Josephson effect in CeCoIn{sub 5} microbridges as seen via quantum interferometry  

SciTech Connect (OSTI)

A superconducting quantum interference device (SQUID) was prepared on a micron-sized single crystal using a selected growth domain of a thin film of CeCoIn{sub 5} grown by molecular beam epitaxy. SQUID voltage oscillations of good quality were obtained as well as interference effects stemming from the individual Josephson microbridges. The transport characteristics in the superconducting state exhibited several peculiarities which we ascribe to the periodic motion of vortices in the microbridges. The temperature dependence of the Josephson critical current shows good correspondence to the Ambegaokar-Baratoff relation, expected for the ideal Josephson junction. The results indicate a promising pathway to identify the type of order parameter in CeCoIn{sub 5} by means of phase-sensitive measurements on microbridges.

Foyevtsov, Oleksandr; Porrati, Fabrizio; Huth, Michael [Physikalisches Institut, Goethe University, Frankfurt am Main, 60438 (Germany)

2011-07-15T23:59:59.000Z

299

Near-infrared induced optical quenching effects on mid-infrared quantum cascade lasers  

SciTech Connect (OSTI)

In space communications, atmospheric absorption and Rayleigh scattering are the dominant channel impairments. Transmission using mid-infrared (MIR) wavelengths offers the benefits of lower loss and less scintillation effects. In this work, we report the telecom wavelengths (1.55??m and 1.3??m) induced optical quenching effects on MIR quantum cascade lasers (QCLs), when QCLs are operated well above their thresholds. The QCL output power can be near 100% quenched using 20?mW of near-infrared (NIR) power, and the quenching effect depends on the input NIR intensity as well as wavelength. Time resolved measurement was conducted to explore the quenching mechanism. The measured recovery time is around 14?ns, which indicates that NIR generated electron-hole pairs may play a key role in the quenching process. The photocarrier created local field and band bending can effectively deteriorate the dipole transition matrix element and quench the QCL. As a result, MIR QCLs can be used as an optical modulator and switch controlled by NIR lasers. They can also be used as “converters” to convert telecom optical signals into MIR optical signals.

Guo, Dingkai, E-mail: dingk1@umbc.edu; Talukder, Muhammad Anisuzzaman; Chen, Xing [Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States); Cai, Hong [Center of Advanced Studies in Photonics Research (CASPR), University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States); Johnson, Anthony M.; Choa, Fow-Sen [Department of Computer Science and Electrical Engineering, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States); Center of Advanced Studies in Photonics Research (CASPR), University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250 (United States); Khurgin, Jacob B. [Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

2014-06-23T23:59:59.000Z

300

Effect of atomic scale plasticity on hydrogen diffusion in iron: Quantum mechanically informed and on-the-fly kinetic  

E-Print Network [OSTI]

viewpoints, is futile. Among several mechanisms proposed for hydrogen embrittlement (HE) of metals, hydrogenEffect of atomic scale plasticity on hydrogen diffusion in iron: Quantum mechanically informed-assisted diffusion and trapping of hydrogen by crystalline defects in iron. Given an embedded atom (EAM) potential

Ortiz, Michael

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Alexander Hall (1) D4 Alumni Center (2) D2  

E-Print Network [OSTI]

Cremona Classrooms (77) E3 Demaray Hall (DH) (8) B2 Eaton Hall (EH) (25) C3 Facility Operations Center Floor Peterson (20) C3 Corporate, Foundation, and Major Gifts, WAC (28) B3 Development, WAC (23) F3

Nelson, Tim

302

Henderson Hall's Education and Career Fair | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Hall's Education and Career Fair September 25, 2014 2:00PM to 5:00PM EDT Location: Smith Gym, Henderson Hall, Arlington, VA POC: Donna Friend Website: http:www.mccshh.com...

303

ORIGINAL PAPER Eric J. Hall Basil V. Worgul Lubomir Smilenov  

E-Print Network [OSTI]

ORIGINAL PAPER Eric J. Hall Ã? Basil V. Worgul Ã? Lubomir Smilenov Carl D. Elliston Ã? David J his colleagues. E. J. Hall (&) Ã? L. Smilenov Ã? C. D. Elliston Ã? D. J. Brenner Center for Radiological

Brenner, David Jonathan

304

EXTENDING CHARACTERS FROM HALL SUBGROUPS GUNTER MALLE AND GABRIEL NAVARRO  

E-Print Network [OSTI]

EXTENDING CHARACTERS FROM HALL SUBGROUPS GUNTER MALLE AND GABRIEL NAVARRO Abstract. Suppose that G AND GABRIEL NAVARRO Lemma 2.1. Suppose that G is -separable and let H be a Hall -subgroup of G. Let L G

Malle, Gunter

305

Waveguide effect of GaAsSb quantum wells in a laser structure based on GaAs  

SciTech Connect (OSTI)

The waveguide effect of GaAsSb quantum wells in a semiconductor-laser structure based on GaAs is studied theoretically and experimentally. It is shown that quantum wells themselves can be used as waveguide layers in the laser structure. As the excitation-power density attains a value of 2 kW/cm{sup 2} at liquid-nitrogen temperature, superluminescence at the wavelength corresponding to the optical transition in bulk GaAs (at 835 nm) is observed.

Aleshkin, V. Ya. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Afonenko, A. A. [Belarussian State University (Belarus)] [Belarussian State University (Belarus); Dikareva, N. V. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation); Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Kudryavtsev, K. E.; Morozov, S. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Nekorkin, S. M. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)

2013-11-15T23:59:59.000Z

306

Edge effects in graphene nanostructures: II. Semiclassical theory of spectral fluctuations and quantum transport  

E-Print Network [OSTI]

We investigate the effect of different edge types on the statistical properties of both the energy spectrum of closed graphene billiards and the conductance of open graphene cavities in the semiclassical limit. To this end, we use the semiclassical Green's function for ballistic graphene flakes that we have derived in Reference 1. First we study the spectral two point correlation function, or more precisely its Fourier transform the spectral form factor, starting from the graphene version of Gutzwiller's trace formula for the oscillating part of the density of states. We calculate the two leading order contributions to the spectral form factor, paying particular attention to the influence of the edge characteristics of the system. Then we consider transport properties of open graphene cavities. We derive generic analytical expressions for the classical conductance, the weak localization correction, the size of the universal conductance fluctuations and the shot noise power of a ballistic graphene cavity. Again we focus on the effects of the edge structure. For both, the conductance and the spectral form factor, we find that edge induced pseudospin interference affects the results significantly. In particular intervalley coupling mediated through scattering from armchair edges is the key mechanism that governs the coherent quantum interference effects in ballistic graphene cavities.

J. Wurm; K. Richter; I. Adagideli

2011-11-14T23:59:59.000Z

307

Scaling in the quantum Hall regime of graphene Corbino devices  

SciTech Connect (OSTI)

The scaling behavior of graphene devices in Corbino geometry was investigated through temperature dependent conductivity measurements under magnetic field. Evaluation of the Landau level width as a function of temperature yielded a relatively low temperature exponent of ??=?0.16?±?0.05. Furthermore, an unusually large value close to 7.6?±?0.9 was found for the universal scaling constant ?, while the determined inelastic scattering exponent of p?=?2 is consistent with established scattering mechanisms in graphene. The deviation of the scaling parameters from values characteristic of conventional two-dimensional electron gases is attributed to an inhomogeneous charge carrier distribution in the Corbino devices. Direct evidence for the presence of the latter could be gained by spatially resolved photocurrent microscopy away from the charge neutrality point of the devices.

Peters, Eva C.; Burghard, Marko [Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Giesbers, A. J. M. [Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Molecular Materials and Nanosystems, Eindhoven University of Technology, NL-5600 MB Eindhoven (Netherlands); Kern, Klaus [Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)

2014-05-19T23:59:59.000Z

308

Spin and Valley Quantum Hall Ferromagnetism in Graphene  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

potential for symmetry breaking phases. In our experiment, we used Landau levels in graphene to study the breaking of SU(4) symmetry-a higher dimensional analog of the symmetry...

309

Tunable fractional quantum Hall phases in bilayer graphene  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Coulomb interactions drive the existence of a correlated many-body state. Bilayer graphene represents a particularly interesting material in which to study the fractional...

310

Contract Periods for 2012-2013 Residence Halls  

E-Print Network [OSTI]

Contract Periods for 2012-2013 Residence Halls All of the residence halls are on Fall/Spring Contracts. THERE IS NO FALL ONLY CONTRACT. · The residence halls open for the fall semester on September 1 rate for the number of days they stay. Apartments Your contract entitles you to an apartment space

Minnesota, University of

311

December 8, 2011 FRONTIER HALL WINTER BREAK CLOSING INFORMATION  

E-Print Network [OSTI]

December 8, 2011 FRONTIER HALL WINTER BREAK CLOSING INFORMATION Frontier Hall will officially close directly before you leave. After 8pm you will no longer be able to access Frontier Hall. Please keep will need during this time. We cannot let you back into Frontier once we have closed for break. If you

Janssen, Michel

312

Introduction Hall and Tank (2005) present estimates of ecosystem metab-  

E-Print Network [OSTI]

213 Introduction Hall and Tank (2005) present estimates of ecosystem metab- olism for Giltner in the estimation of ecosystem metabolism by open-channel methods (McCutchan et al. 2002; Hall and Tank 2005). To estimate metabolism in Giltner Spring Creek, Hall and Tank (2005) employ a mass-balance equation

Lewis Jr., William M.

313

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well  

SciTech Connect (OSTI)

The relaxation of lattice-mismatched strain by deep postetching was systematically investigated for InGaN/GaN multiple quantum wells (MQWs). A planar heterojunction wafer, which included an In{sub 0.21}Ga{sub 0.79}N (3.2 nm)/GaN (14.8 nm) MQW, was etched by inductively coupled plasma dry etching, to fabricate high-density nanopillar, nanostripe, and nanohole arrays. The etching depth was 570 nm for all nanostructures. The diameter of the nanopillars was varied from 50 to 300 nm, then the mesa stripe width of the nanostripes and the diameter of the nanoholes were varied from 100 nm to 440 nm and 50 nm to 310 nm, respectively. The effect of strain relaxation on various optical properties was investigated. For example, in an array of nanopillars with diameter 130 nm and interval 250 nm, a large blueshift in the photoluminescence (PL) emission peak from 510 nm (as-grown) to 459 nm occurred at room temperature (RT). PL internal quantum efficiency (defined by the ratio of PL integral intensity at 300 K to that at 4.2 K) was enhanced from 34% (as-grown) to 60%, and the PL decay time at 4.2 K was reduced from 22 ns (as-grown) to 4.2 ns. These results clearly indicate the reduction of lattice-mismatched strain by postetching, which enhanced strain reduction with decreasing nanopillar diameter down to a diameter of 130 nm, where the strain reduction became saturated. The dependence of RT-PL decay time on nanopillar diameter was measured, and the surface nonradiative recombination velocity was estimated to be 5.8x10{sup 2} cm/s. This relatively slow rate indicates a little etching damage.

Ramesh, V.; Kikuchi, A.; Kishino, K. [Department of Electrical and Electronics Engineering, Sophia University, Tokyo 102-8554, Japan and Nano-technology Research Center, Sophia University, Tokyo 102-8554 (Japan); CREST, JST, Saitama 332-0012 (Japan); Funato, M.; Kawakami, Y. [CREST, JST, Saitama 332-0012 (Japan); Department of Electronics Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2010-06-15T23:59:59.000Z

314

Electrical and Optical Gain Lever Effects in InGaAs Double Quantum Well Diode Lasers  

SciTech Connect (OSTI)

In multisection laser diodes, the amplitude or frequency modulation (AM or FM) efficiency can be improved using the gain lever effect. To study gain lever, InGaAs double quantum well (DQW) edge emitting lasers have been fabricated with integrated passive waveguides and dual sections providing a range of split ratios from 1:1 to 9:1. Both the electrical and the optical gain lever have been examined. An electrical gain lever with greater than 7 dB enhancement of AM efficiency was achieved within the range of appropriate DC biasing currents, but this gain dropped rapidly outside this range. We observed a 4 dB gain in the optical AM efficiency under non-ideal biasing conditions. This value agreed with the measured gain for the electrical AM efficiency under similar conditions. We also examined the gain lever effect under large signal modulation for digital logic switching applications. To get a useful gain lever for optical gain quenched logic, a long control section is needed to preserve the gain lever strength and a long interaction length between the input optical signal and the lasing field of the diode must be provided. The gain lever parameter space has been fully characterized and validated against numerical simulations of a semi-3D hybrid beam propagation method (BPM) model for the coupled electron-photon rate equation. We find that the optical gain lever can be treated using the electrical injection model, once the absorption in the sample is known.

Pocha, M D; Goddard, L L; Bond, T C; Nikolic, R J; Vernon, S P; Kallman, J S; Behymer, E M

2007-01-03T23:59:59.000Z

315

Integrated Learning Centre Beamish-Munro Hall  

E-Print Network [OSTI]

. Beamish-Munro Hall is a green building. It has a rating equiva- lent to LEED silver,received a 2005 Award at the 2005 Sustainable Buildings Conference in Tokyo. quick FACT LOGIN On our computers,select AD to complement the classroom experience,enhancing de- sign,team and professional skills development. For Students

Linder, Tamás

316

Alan Turing, Marshall Hall, and the Alignment  

E-Print Network [OSTI]

Alan Turing, Marshall Hall, and the Alignment of WW2 Japanese Naval Intercepts Peter W. Donovan M work in all areas, from the Japanese codes to the German Enigma machine which Alan Turing had begun of communications intelligence to the WW2 Allies in the Pacific. Alan Turing's Work on Applied Probability

Wright, Francis

317

Forensic Entomology & Taphonomy Smith Hall Room 125  

E-Print Network [OSTI]

ENTM 295T Forensic Entomology & Taphonomy Smith Hall Room 125 Monday 8:30 ­ 11:20 a.m. Fall and on the postmortem fate of human remains. Ralph Williams, Ph.D. D-ABFE Professor of Entomology Entomology, Smith B9

Ginzel, Matthew

318

DINING HALL CATERING TENDER SCOPE OF WORK  

E-Print Network [OSTI]

Facilities creating a pleasing ambience and student-friendly dining environment 4. FOOD SERVICE REQUIREMENTS movements and activities, and preferences. 2. Project Definition The University requires the Service Provider to provide the Services at the following Catering Facilities: a. Main Dining Hall (Students' Union

Wagner, Stephan

319

Air Temperature in the Undulator Hall  

SciTech Connect (OSTI)

Various analyses have been performed recently to estimate the performance of the air conditioning (HVAC) system planned for the Undulator Hall. This reports summarizes the results and provides an upgrade plan to be used if new requirements are needed in the future. The estimates predict that with the planned loads the tunnel air temperature will be well within the allowed tolerance during normal operation.

Not Available

2010-12-07T23:59:59.000Z

320

Dr. Kanarek 8/9/2011 175 Science Hall 1;00-2:15 Tu, Th  

E-Print Network [OSTI]

Sept 8 History of air pollution problem -- The Disasters Tu Sept 13 Risk Assessment (Concepts of Health Th Oct 20 Ozone Health Effects Tu Oct 25 EXAM I Th Oct 27Indoor Air Pollution Overview #12;Tu Nov 1Dr. Kanarek 8/9/2011 175 Science Hall 1;00-2:15 Tu, Th PHS/Env St 502: Air Pollution and Human

Sheridan, Jennifer

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Interface effect of InSb quantum dots embedded in SiO{sub 2} matrix  

SciTech Connect (OSTI)

The interface effect of InSb quantum dots (QDs) embedded in SiO{sub 2} matrix has been investigated by Raman scattering spectroscopy, x-ray diffraction (XRD), and x-ray absorption fine structure (both of EXAFS and XANES). The EXAFS and XRD results show clearly that the bond length of the Sb-In first shell of the InSb QDs contracts slightly about 0.02 A compared with that of the bulk InSb. The Raman scattering spectrum of the InSb QDs reveals that the lattice contraction partly weakens the phonon confinement effect. The coordination geometry at the interface of the InSb QDs is mainly Sb (In)-O covalent bridge bonds. The Sb K-XANES calculations of InSb QDs embedded in SiO{sub 2} matrix based on FEFF8 indicate that the intensity increase and the broadening of the white line peak of Sb atoms are essentially attributed to both the increase of Sb p-hole population and the change of Sb intra-atomic potential {mu}{sub 0}(E) affected by the SiO{sub 2} matrix. Our results show that the interface effect between the InSb QDs and the SiO{sub 2} matrix leads not only to the slight lattice contraction of InSb QDs and the large structural distortion in the interface area of InSb QDs, but also to the significant change of the Sb intra-atomic potential and the obvious charge redistribution around Sb atoms.

Chen Dongliang; Fan Jiangwei; Wei Shiqiang [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029 (China); Li Chaosheng; Zhu Zhengang [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, PO Box 1129, Hefei 230031 (China)

2005-08-15T23:59:59.000Z

322

Influence of image charge effect on exciton fine structure in an organic-inorganic quantum well material  

SciTech Connect (OSTI)

We have investigated experimentally excitonic properties in organic-inorganic hybrid multi quantum well crystals, (C{sub 4}H{sub 9}NH{sub 3}){sub 2}PbBr{sub 4} and (C{sub 6}H{sub 5}?C{sub 2}H{sub 4}NH{sub 3}){sub 2}PbBr{sub 4}, by measuring photoluminescence, reflectance, photoluminescence excitation spectra. In these materials, the excitonic binding energies are enhanced not only by quantum confinement effect (QCE) but also by image charge effect (ICE), since the dielectric constant of the barrier layers is much smaller than that of the well layers. By comparing the 1s-exciton and 2s-exciton energies, we have investigated the influence of ICE with regard to the difference of the Bohr radius.

Takagi, Hidetsugu; Kunugita, Hideyuki; Ema, Kazuhiro [Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Sato, Mikio; Takeoka, Yuko [Department of Materials and Life Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan)

2013-12-04T23:59:59.000Z

323

Enhancement of fusion rates due to quantum effects in the particles momentum distribution in nonideal media  

E-Print Network [OSTI]

This study concerns a situation when measurements of the nonresonant cross-section of nuclear reactions appear highly dependent on the environment in which the particles interact. An appealing example discussed in the paper is the interaction of a deuteron beam with a target of deuterated metal Ta. In these experiments, the reaction cross section for d(d,p)t was shown to be orders of magnitude greater than what the conventional model predicts for the low-energy particles. In this paper we take into account the influence of quantum effects due to the Heisenberg uncertainty principle for particles in a non-ideal medium elastically interacting with the medium particles. In order to calculate the nuclear reaction rate in the non-ideal environment we apply both the Monte Carlo technique and approximate analytical calculation of the Feynman diagram using nonrelativistic kinetic Green's functions in the medium which correspond to the generalized energy and momentum distribution functions of interacting particles. We...

Fisch, N J; Petrushevich, Yu V; Quarati, Piero; Starostin, A N

2011-01-01T23:59:59.000Z

324

A functional approach to quantum friction: effective action and dissipative force  

E-Print Network [OSTI]

We study the Casimir friction due to the relative, uniform, lateral motion of two parallel semitransparent mirrors coupled to a vacuum real scalar field, $\\phi$. We follow a functional approach, whereby nonlocal terms in the action for $\\phi$, concentrated on the mirrors' locii, appear after functional integration of the microscopic degrees of freedom. This action for $\\phi$, which incorporates the relevant properties of the mirrors, is then used as the starting point for two complementary evaluations: Firstly, we calculate the { in-out} effective action for the system, which develops an imaginary part, hence a non-vanishing probability for the decay (because of friction) of the initial vacuum state. Secondly, we evaluate another observable: the vacuum expectation value of the frictional force, using the { in-in} or Closed Time Path formalism. Explicit results are presented for zero-width mirrors and half-spaces, in a model where the microscopic degrees of freedom at the mirrors are a set of identical quantum harmonic oscillators, linearly coupled to $\\phi$

M. Belén Farías; César D. Fosco; Fernando C. Lombardo; Francisco D. Mazzitelli; Adrián E. Rubio López

2014-12-30T23:59:59.000Z

325

The Casimir effect from the point of view of algebraic quantum field theory  

E-Print Network [OSTI]

We consider a region of Minkowski spacetime bounded either by one or by two parallel, infinitely extended plates orthogonal to a spatial direction and a real Klein-Gordon field satisfying Dirichlet boundary conditions. We quantize these two systems within the algebraic approach to quantum field theory using the so-called functional formalism. As a first step we construct a suitable unital *-algebra of observables whose generating functionals are characterized by a labeling space which is at the same time optimal and separating. Subsequently we give a definition for these systems of Hadamard states and we investigate explicit examples. In the case of a single plate, it turns out that one can build algebraic states via a pull-back of those on the whole Minkowski spacetime, moreover inheriting from them the Hadamard property. When we consider instead two plates, algebraic states can be put in correspondence with those on flat spacetime via the so-called method of images, which we translate to the algebraic setting. For a massless scalar field we show that this procedure works perfectly for a large class of quasi-free states including the Poincar\\'e vacuum and KMS states. Eventually we use our results in both systems to introduce the notion of Wick polynomials, showing that a global extended algebra does not exist. Furthermore we construct explicitly the two-point function and the regularized energy density, showing, moreover, that the outcome is consistent with the standard results of the Casimir effect.

Claudio Dappiaggi; Gabriele Nosari; Nicola Pinamonti

2014-12-03T23:59:59.000Z

326

Effect of graphene on photoluminescence properties of graphene/GeSi quantum dot hybrid structures  

SciTech Connect (OSTI)

Graphene has been discovered to have two effects on the photoluminescence (PL) properties of graphene/GeSi quantum dot (QD) hybrid structures, which were formed by covering monolayer graphene sheet on the multilayer ordered GeSi QDs sample surfaces. At the excitation of 488?nm laser line, the hybrid structure had a reduced PL intensity, while at the excitation of 325?nm, it had an enhanced PL intensity. The attenuation in PL intensity can be attributed to the transferring of electrons from the conducting band of GeSi QDs to the graphene sheet. The electron transfer mechanism was confirmed by the time resolved PL measurements. For the PL enhancement, a mechanism called surface-plasmon-polariton (SPP) enhanced absorption mechanism is proposed, in which the excitation of SPP in the graphene is suggested. Due to the resonant excitation of SPP by incident light, the absorption of incident light is much enhanced at the surface region, thus leading to more exciton generation and a PL enhancement in the region. The results may be helpful to provide us a way to improve optical properties of low dimensional surface structures.

Chen, Y. L.; Ma, Y. J.; Wang, W. Q.; Ding, K.; Wu, Q.; Fan, Y. L.; Yang, X. J.; Zhong, Z. Y.; Jiang, Z. M., E-mail: zmjiang@fudan.edu.cn [State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433 (China); Chen, D. D.; Xu, F. [SHU-SolarE R and D Lab, Department of Physics, College of Science, Shanghai University, Shanghai 200444 (China)

2014-07-14T23:59:59.000Z

327

An analysis of quantum effects on the thermodynamic properties of cryogenic hydrogen using the path integral method  

SciTech Connect (OSTI)

In this paper, we describe the analysis of the thermodynamic properties of cryogenic hydrogen using classical molecular dynamics (MD) and path integral MD (PIMD) method to understand the effects of the quantum nature of hydrogen molecules. We performed constant NVE MD simulations across a wide density–temperature region to establish an equation of state (EOS). Moreover, the quantum effect on the difference of molecular mechanism of pressure–volume–temperature relationship was addressed. The EOS was derived based on the classical mechanism idea only using the MD simulation results. Simulation results were compared with each MD method and experimental data. As a result, it was confirmed that although the EOS on the basis of classical MD cannot reproduce the experimental data of saturation property of hydrogen in the high-density region, the EOS on the basis of PIMD well reproduces those thermodynamic properties of hydrogen. Moreover, it was clarified that taking quantum effects into account makes the repulsion force larger and the potential well shallower. Because of this mechanism, the intermolecular interaction of hydrogen molecules diminishes and the virial pressure increases.

Nagashima, H., E-mail: nagashima@nanoint.ifs.tohoku.ac.jp [School of Engineering, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tsuda, S. [Department of Mechanical Systems Engineering, Shinshu University, Nagano 380-8553 (Japan)] [Department of Mechanical Systems Engineering, Shinshu University, Nagano 380-8553 (Japan); Tsuboi, N. [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550 (Japan)] [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550 (Japan); Koshi, M. [Graduate School of Environment and Information Science, Yokohama National University, Yokohama 240-8501 (Japan)] [Graduate School of Environment and Information Science, Yokohama National University, Yokohama 240-8501 (Japan); Hayashi, K. A. [Department of Mechanical Engineering, Aoyama Gakuin University, Sagamihara 229-8558 (Japan)] [Department of Mechanical Engineering, Aoyama Gakuin University, Sagamihara 229-8558 (Japan); Tokumasu, T. [Institute of Fluid Science, Tohoku University, Sendai 980-8577 (Japan)] [Institute of Fluid Science, Tohoku University, Sendai 980-8577 (Japan)

2014-04-07T23:59:59.000Z

328

Quantum noise and radiation pressure effects in high power optical interferometers  

E-Print Network [OSTI]

In recent years, a variety of mechanical systems have been approaching quantum limits to their sensitivity of continuous position measurements imposed by the Heisenberg Uncertainty Principle. Most notably, gravitational ...

Corbitt, Thomas Randall

2008-01-01T23:59:59.000Z

329

Structure transitions induced by the Hall term in homogeneous and isotropic magnetohydrodynamic turbulence  

SciTech Connect (OSTI)

Hall effects on local structures in homogeneous, isotropic, and incompressible magnetohydrodynamic turbulence are studied numerically. The transition of vortices from sheet-like to tubular structures induced by the Hall term is found, while the kinetic energy spectrum does not distinguish the two types of structures. It is shown by the use of the sharp low-pass filter that the transition occurs not only in the scales smaller than the ion skin depth but also in a larger scale. The transition is related with the forward energy transfer in the spectral space. Analyses by the use of the sharp low-pass filter show that the nonlinear energy transfer associated with the Hall term is dominated by the forward transfer and relatively local in the wave number space. A projection of the simulation data to a Smagorinsky-type sub-grid-scale model shows that the high wave number component of the Hall term may possibly be replaced by the model effectively.

Miura, H., E-mail: miura.hideaki@nifs.ac.jp [Department of Helical Plasma Research, National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292 (Japan); Araki, K. [Faculty of Engineering, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005 (Japan)

2014-07-15T23:59:59.000Z

330

Changing quantum reference frames  

E-Print Network [OSTI]

We consider the process of changing reference frames in the case where the reference frames are quantum systems. We find that, as part of this process, decoherence is necessarily induced on any quantum system described relative to these frames. We explore this process with examples involving reference frames for phase and orientation. Quantifying the effect of changing quantum reference frames serves as a first step in developing a relativity principle for theories in which all objects including reference frames are necessarily quantum.

Matthew C. Palmer; Florian Girelli; Stephen D. Bartlett

2014-05-21T23:59:59.000Z

331

U.S. WRESTLING FEDERATION HALL  

E-Print Network [OSTI]

S-86 S-87 S-36 S-85 S-90 S-75 S-76 HOUSE #6 S-89 S-91 OFFICE CENTER AGRICULTURE U.S.D.A. S-92 S-88. SMITH HALL ALUMNI CENTER HOUSING - JPI PHASE 1 BUILDING 3 HOUSING - JPI PHASE 1 BUILDING 4 STUDENT UNION. LAUNDRY RESOURCE Y CAGE LAB. POULTRY BATTERY LAB. BROODER FIRE TECH. OUTDOOR LAB. MO. LAB. GY CONS. CHAPEL

Veiga, Pedro Manuel Barbosa

332

Quantum Physics and Nanotechnology  

E-Print Network [OSTI]

Experimental studies of infinite (unrestricted at least in one direction) quantum particle motion using probe nanotechnologies have revealed the necessity of revising previous concepts of their motion. Particularly, quantum particles transfer quantum motion nonlocality energy beside classical kinetic energy, in other words, they are in two different kinds of motion simultaneously. The quantum component of the motion energy may be quite considerable under certain circumstances. Some new effects were predicted and proved experimentally in terms of this phenomenon. A new prototype refrigerating device was tested, its principle of operation being based on the effect of transferring the quantum component of the motion energy.

Vladimir K. Nevolin

2011-06-06T23:59:59.000Z

333

Valley pair qubits in double quantum dots of gapped graphene  

E-Print Network [OSTI]

The rise of graphene opens a new door to qubit implementation, as discussed in the recent proposal of valley pair qubits in double quantum dots of gapped graphene (Wu et al., arXiv: 1104.0443 [cond-mat.mes-hall]). The work here presents the comprehensive theory underlying the proposal. It discusses the interaction of electrons with external magnetic and electric fields in such structures. Specifically, it examines a strong, unique mechanism, i.e., the analogue of the 1st-order relativistic effect in gapped graphene. This mechanism is state mixing free and allows, together with the electrically tunable exchange coupling, a fast, all-electric manipulation of qubits via electric gates, in the time scale of ns. The work also looks into the issue of fault tolerance in a typical case, yielding at 10oK a long qubit coherence time (~O(ms)).

G. Y. Wu; N. -Y. Lue; L. Chang

2011-07-03T23:59:59.000Z

334

Dirac Quantization and Fractional Magnetoelectric Effect on Interacting Topological Insulators  

E-Print Network [OSTI]

We use Dirac quantization of flux to study fractional charges and axion angles \\theta in interacting topological insulators with gapless surface modes protected by time-reversal symmetry. In interacting topological insulators, there are two types of fractional axion angle due to conventional odd and nontrivial even flux quantization at the boundary. On even flux quantization in a gapped time reversal invariant system, we show that there is a halved quarter fractional quantum Hall effect on the surface with Hall conductance of p/4q e2/2h with p and q odd integers. The gapless surface modes can be characterized by a nontrivial Z2 anomaly emerged from the even flux quantization. It is suggested that the electron can be regarded as a bound state of fractionally charged quarks confined by a nonabelian color gauge field on the Dirac quantization of complex spinor fields.

K. -S. Park; H. Han

2010-10-10T23:59:59.000Z

335

A fully 3D atomistic quantum mechanical study on random dopant induced effects in 25nm MOSFETs  

E-Print Network [OSTI]

A Fully 3D Atomistic Quantum Mechanical Study on RandomWang* Abstract— We present a fully 3D atomistic quantum me-Dopant ?uctuation, MOSFETs, 3D, threshold, LCBB, quantum

Jiang, Xiang-Wei

2008-01-01T23:59:59.000Z

336

Quantum Biology  

E-Print Network [OSTI]

A critical assessment of the recent developments of molecular biology is presented. The thesis that they do not lead to a conceptual understanding of life and biological systems is defended. Maturana and Varela's concept of autopoiesis is briefly sketched and its logical circularity avoided by postulating the existence of underlying {\\it living processes}, entailing amplification from the microscopic to the macroscopic scale, with increasing complexity in the passage from one scale to the other. Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces, is criticized. It is suggested that the correct interpretation of quantum dispersion forces (van der Waals, hydrogen bonding, and so on) as quantum coherence effects hints at the necessity of including long-ranged forces (or mechanisms for them) in condensed matter theories of biological processes. Some quantum effects in biology are reviewed and quantum mechanics is acknowledged as conceptually important to biology since without it most (if not all) of the biological structures and signalling processes would not even exist. Moreover, it is suggested that long-range quantum coherent dynamics, including electron polarization, may be invoked to explain signal amplification process in biological systems in general.

Alessandro Sergi

2009-07-11T23:59:59.000Z

337

Nonlinear friction in quantum mechanics  

E-Print Network [OSTI]

The effect of nonlinear friction forces in quantum mechanics is studied via dissipative Madelung hydrodynamics. A new thermo-quantum diffusion equation is derived, which is solved for the particular case of quantum Brownian motion with a cubic friction. It is extended also by a chemical reaction term to describe quantum reaction-diffusion systems with nonlinear friction as well.

Roumen Tsekov

2010-03-01T23:59:59.000Z

338

SCHOOL OF COMPUTING SCIENCE Exam Code Exam Name Day Exam date Time Exam Hall Hall Split  

E-Print Network [OSTI]

:00 Room 601 Rankine Building COMPSCI4062_1 Cyber Security 4 Wed 07/05/2014 09:30 - 11:30 Room 201 John Mc5063_1 Cyber Security M Wed 07/05/2014 09:30 - 11:30 Fore Hall COMPSCI4014_1 CS3W:Interactive Systems 3/05/2014 09:30 - 11:30 Fore Hall COMPSCI4019_1 Distributed Algs & Systems 4 Thu 08/05/2014 14:00 - 16

Glasgow, University of

339

1 Austin Hall rms 189 & 405 2 Bexell rm 117  

E-Print Network [OSTI]

's Restroom Annex 15 Ocean Admin · rm 101a 16 Peavy Hall · rm A030C 17 Radiation Center · rm B126a 18 Reed

Escher, Christine

340

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;

342

Building America Top Innovations Hall of Fame Profile ? Outside...  

Energy Savers [EERE]

worked with Monley Cronin Construction to build 100 energy-efficient homes in Woodland, CA, with night- cooling ventilation systems. BUILDING AMERICA TOP INNOVATIONS HALL OF FAME...

343

Rebuilding It Better: Greensburg, Kansas. City Hall (Brochure)  

Office of Energy Efficiency and Renewable Energy (EERE)

This brochure details the energy efficient and sustainable aspects of the LEED Platinum-designated City Hall building in Greensburg, Kansas.

344

Building America Top Innovations Hall of Fame Profile - Building...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Building America Top Innovations Hall of Fame Profile - Building America's Top Innovations Propel the Home Building Industry toward Higher Performance Building America Top...

345

Effective detective quantum efficiency for two mammography systems: Measurement and comparison against established metrics  

SciTech Connect (OSTI)

Purpose: The aim of this paper was to illustrate the value of the new metric effective detective quantum efficiency (eDQE) in relation to more established measures in the optimization process of two digital mammography systems. The following metrics were included for comparison against eDQE: detective quantum efficiency (DQE) of the detector, signal difference to noise ratio (SdNR), and detectability index (d?) calculated using a standard nonprewhitened observer with eye filter.Methods: The two systems investigated were the Siemens MAMMOMAT Inspiration and the Hologic Selenia Dimensions. The presampling modulation transfer function (MTF) required for the eDQE was measured using two geometries: a geometry containing scattered radiation and a low scatter geometry. The eDQE, SdNR, and d? were measured for poly(methyl methacrylate) (PMMA) thicknesses of 20, 40, 60, and 70 mm, with and without the antiscatter grid and for a selection of clinically relevant target/filter (T/F) combinations. Figures of merit (FOMs) were then formed from SdNR and d? using the mean glandular dose as the factor to express detriment. Detector DQE was measured at energies covering the range of typical clinically used spectra.Results: The MTF measured in the presence of scattered radiation showed a large drop at low spatial frequency compared to the low scatter method and led to a corresponding reduction in eDQE. The eDQE for the Siemens system at 1 mm{sup ?1} ranged between 0.15 and 0.27, depending on T/F and grid setting. For the Hologic system, eDQE at 1 mm{sup ?1} varied from 0.15 to 0.32, again depending on T/F and grid setting. The eDQE results for both systems showed that the grid increased the system efficiency for PMMA thicknesses of 40 mm and above but showed only small sensitivity to T/F setting. While results of the SdNR and d? based FOMs confirmed the eDQE grid position results, they were also more specific in terms of T/F selection. For the Siemens system at 20 mm PMMA, the FOMs indicated Mo/Mo (grid out) as optimal while W/Rh (grid in) was the optimal configuration at 40, 60, and 70 mm PMMA. For the Hologic, the FOMs pointed to W/Rh (grid in) at 20 and 40 mm of PMMA while W/Ag (grid in) gave the highest FOM at 60 and 70 mm PMMA. Finally, DQE at 1 mm{sup ?1} averaged for the four beam qualities studied was 0.44 ± 0.02 and 0.55 ± 0.03 for the Siemens and Hologic detectors, respectively, indicating only a small influence of energy on detector DQE.Conclusions: Both the DQE and eDQE data showed only a small sensitivity to T/F setting for these two systems. The eDQE showed clear preferences in terms of scatter reduction, being highest for the grid-in geometry for PMMA thicknesses of 40 mm and above. The SdNR and d? based figures of merit, which contain additional weighting for contrast and dose, pointed to specific T/F settings for both systems.

Salvagnini, Elena [UZ Gasthuisberg, Medical Imaging Research Center and Department of Radiology, Herestraat 49, B-3000 Leuven, Belgium and SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)] [UZ Gasthuisberg, Medical Imaging Research Center and Department of Radiology, Herestraat 49, B-3000 Leuven, Belgium and SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Bosmans, Hilde; Marshall, Nicholas W. [UZ Gasthuisberg, Medical Imaging Research Center and Department of Radiology, Herestraat 49, B-3000 Leuven (Belgium)] [UZ Gasthuisberg, Medical Imaging Research Center and Department of Radiology, Herestraat 49, B-3000 Leuven (Belgium); Struelens, Lara [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)] [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)

2013-10-15T23:59:59.000Z

346

Cross-Kerr-effect induced by coupled Josephson qubits in circuit quantum electrodynamics  

SciTech Connect (OSTI)

We propose a scheme for implementing cross-Kerr nonlinearity between two superconducting transmission line resonators (TLRs) via their interactions with a coupler constructed by two superconducting transmon qubits connected to each other through a superconducting quantum interference device. When suitably driven, the coupler can induce very strong cross phase modulation (XPM) between the two TLRs due to its N-type level structure and the consequent electromagnetically induced transparency in its lowest states. The flexibility of our design can lead to various inter-TLR coupling configurations. The obtained cross-Kerr coefficient is large enough to allow many important quantum operations in which only few photons are involved. We further show that this scheme is very robust against fluctuations in solid-state quantum circuits. Our numerical calculations imply that the absorption and the dispersion of the TLRs resulting from the decoherence of the coupler are very small compared with the proposed XPM strength.

Hu Yong; Ge Guoqin; Chen Shi; Yang Xiaofei; Chen Youling [School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Department of Physics, Peking University, Beijing 100871 (China)

2011-07-15T23:59:59.000Z

347

Schedule and cost estimate for an innovative Boston Harbor concert hall  

E-Print Network [OSTI]

This thesis formulates a cost estimate and schedule for constructing the Boston Concert Hall, an innovative hypothetical building composed of two concert halls and a restaurant. Concert Halls are complex and expensive ...

Coste, Amelie, 1982-

2004-01-01T23:59:59.000Z

348

A Proposed Alternative Low Energy Quantum Field Theory of Gravity Based on a Bose-Einstein Condensate Effect  

E-Print Network [OSTI]

An alternative quantum field theory for gravity is proposed for low energies based on an attractive effect between contaminants in a Bose-Einstein Condensate rather than on particle exchange. In the ``contaminant in condensate effect," contaminants cause a potential in an otherwise uniform condensate, forcing the condensate between two contaminants to a higher energy state. The energy of the system decreases as the contaminants come closer together, causing an attractive force between contaminants. It is proposed that mass-energy may have a similar effect on Einstein's space-time field, and gravity is quantized by the same method by which the contaminant in condensate effect is quantized. The resulting theory is finite and, if a physical condensate is assumed to underly the system, predictive. However, the proposed theory has several flaws at high energies and is thus limited to low energies. Falsifiable predictions are given for the case that the Higgs condensate is assumed to be the condensate underlying gravity.

Alexander Oshmyansky

2007-03-08T23:59:59.000Z

349

On quantum effects in the vicinity of would-be horizons  

E-Print Network [OSTI]

We present a method based on the so-called Quantum Energy Inequalities, which allows to compare, and bound, the expectation values of energy-densities of ground states of quantum fields in spacetimes possessing isometric regions. The method supports the conclusion, that the Boulware energy density is universal both: at modest (and far) distances from compact spherical objects, and close to the would-be horizons of the gravastar/QBHO spacetimes. It also provides a natural consistency check for concrete (approximate, numerical) calculations of the expectation values of the energy-momentum tensors.

P. Marecki

2006-12-28T23:59:59.000Z

350

Beam Loss Ion Chamber System Upgrade for Experimental Halls  

SciTech Connect (OSTI)

The Beam loss Ion Chamber System (BLICS) was developed to protect Jefferson Labs transport lines, targets and beam dumps from a catastrophic ''burn through''. Range changes and testing was accomplished manually requiring the experiment to be shut down. The new upgraded system is based around an ''off the shelf'' Programmable Logic Controller located in a single control box supporting up to ten individual detectors. All functions that formerly required an entry into the experimental hall and manual adjustment can be accomplished from the Machine Control Center (MCC). A further innovation was the addition of a High Voltage ''Brick'' at the detector location. A single cable supplies the required voltage for the Brick and a return line for the ion chamber signal. The read back screens display range, trip point, and accumulated dose for each location. The new system is very cost effective and significantly reduces the amount of lost experimental time.

D.W. Dotson; D.J. Seidman

2005-05-16T23:59:59.000Z

351

Trajectories without quantum uncertainties  

E-Print Network [OSTI]

A common knowledge suggests that trajectories of particles in quantum mechanics always have quantum uncertainties. These quantum uncertainties set by the Heisenberg uncertainty principle limit precision of measurements of fields and forces, and ultimately give rise to the standard quantum limit in metrology. With the rapid developments of sensitivity of measurements these limits have been approached in various types of measurements including measurements of fields and acceleration. Here we show that a quantum trajectory of one system measured relatively to the other "reference system" with an effective negative mass can be quantum uncertainty--free. The method crucially relies on the generation of an Einstein-Podolsky-Rosen entangled state of two objects, one of which has an effective negative mass. From a practical perspective these ideas open the way towards force and acceleration measurements at new levels of sensitivity far below the standard quantum limit.

Eugene S. Polzik; Klemens Hammerer

2014-05-13T23:59:59.000Z

352

Effect of the (OH) Surface Capping on ZnO Quantum Dots  

E-Print Network [OSTI]

in air at different temperatures from 150­500 C for 30 min. In comparison, highly purified bulk Zn is related to oxygen deficiency [1]; the other is a much narrower ultraviolet (UV) emission band at around, compared with good quality ZnO single crystals or ZnO powders, the UV bandgap luminescence in quantum dots

Nabben, Reinhard

353

Quantum corrections and bound-state effects in the energy relaxation of hot dense Hydrogen  

E-Print Network [OSTI]

Simple analytic formulae for energy relaxation (ER) in electron-ion systems, with quantum corrections, ion dynamics and RPA-type screening are presented. ER in the presence of bound electrons is examined in view of of recent simulations for ER in hydrogen in the range 10^{20}-10^{24} electrons/cc.

M. W. C. Dharma-Wardana

2008-04-13T23:59:59.000Z

354

E-Print Network 3.0 - aps experiment hall Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

New York State... Agricultural Experiment Station campus Cornell Business & Technology Park 10 Brown Road 20 Thornwood Road 33... White Hall Clark Hall Mann Library Uris...

355

Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations  

SciTech Connect (OSTI)

The degree of circular polarization of photoluminescence of (In,Ga)As quantum dots as a function of magnetic field applied perpendicular to the optical axis (Hanle effect) is experimentally studied. The measurements have been performed at various regimes of the optical excitation modulation. The analysis of experimental data has been performed in the framework of a vector model of regular nuclear spin polarization and its fluctuations. The analysis allowed us to evaluate the magnitude of nuclear polarization and its dynamics at the experimental conditions used.

Gerlovin, I. Ya. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg (Russian Federation); Cherbunin, R. V.; Ignatiev, I. V.; Kuznetsova, M. S.; Verbin, S. Yu. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg, Russia and Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Flisinski, K.; Bayer, M. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yakovlev, D. R. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany and A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)

2013-12-04T23:59:59.000Z

356

RCP Spring 2011 SPONSORS MEETING PETROLEUM HALL, GREEN CENTER  

E-Print Network [OSTI]

RCP Spring 2011 SPONSORS MEETING PETROLEUM HALL, GREEN CENTER Colorado School of Mines ­ Friedhoff Hall (Lower Level of Green Center) 1:00 - 2:30 PM Postle Field Reservoir Characterization and Pouce Coupe Fields: Matt Billingsley, CSM and Jared Atkinson, Talisman Energy 3:45 - 5:00 PM

357

413 South Hall Bowling Green, OH 43403-0185  

E-Print Network [OSTI]

(Street, City, State, and Zip Code): I , a student at Bowling Green State University give permission413 South Hall Bowling Green, OH 43403-0185 Phone 419-372-8495, TTY 419-372-9455 Fax 419 with specific test results or clinical observations. #12;Page 2 of 4 413 South Hall Bowling Green, OH 43403

Moore, Paul A.

358

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New://newswire.rockefeller.edu/?page=engine&id=939 Nidhi Sabharwal, Ph.D. Technology Manager Office of Technology Transfer (212) 327-7092 nsabharwal@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New

359

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www

360

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New.1217207109 Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New activation. Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New

362

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10065 www

363

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue NewRNA and antisense therapeutics Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New

364

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto

de Lange, Titia

365

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Sabharwal, Ph.D. Technology Manager Office of Technology Transfer (212) 327-7092 nsabharwal@rockefeller.edu #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New

366

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New:1484-1488. #12;The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology

367

Index theorem, spin Chern Simons theory and fractional magnetoelectric effect in strongly correlated topological insulators  

E-Print Network [OSTI]

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 $.

K. -S. Park; H. Han

2011-05-31T23:59:59.000Z

368

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures  

SciTech Connect (OSTI)

In this paper, we report on the effects of including Si-doped (In)GaN prelayers on the low temperature optical properties of a blue-light emitting InGaN/GaN single quantum well. We observed a large blue shift of the photoluminescence peak emission energy and significant increases in the radiative recombination rate for the quantum well structures that incorporated Si-doped prelayers. Simulations of the variation of the conduction and valence band energies show that a strong modification of the band profile occurs for the quantum wells on Si-doped prelayers due to an increase in strength of the surface polarization field. The enhanced surface polarization field opposes the built-in field across the quantum well and thus reduces this built-in electric field. This reduction of the electric field across the quantum well reduces the Quantum Confined Stark Effect and is responsible for the observed blue shift and the change in the recombination dynamics.

Davies, M. J., E-mail: Matthew.Davies-2@Manchester.ac.uk; Dawson, P. [School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL (United Kingdom); Massabuau, F. C.-P.; Oliver, R. A.; Kappers, M. J.; Humphreys, C. J. [Department of Material Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2014-09-01T23:59:59.000Z

369

Undulator Hall Air Temperature Fault Scenarios  

SciTech Connect (OSTI)

Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about {+-}2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.

Sevilla, J.; Welch, J.; /SLAC; ,

2010-11-17T23:59:59.000Z

370

Effect of pressure on the quantum spin ladder material IPA-CuCl3.  

SciTech Connect (OSTI)

Inelastic-neutron-scattering and bulk magnetic-susceptibility studies of the quantum S = 1/2 spin ladder system (CH{sub 3}){sub 2}CHNH{sub 3}CuCl{sub 3} are performed under hydrostatic pressure. The pressure dependence of the spin gap {Delta} is determined. At P = 1500 MPa it is reduced to {Delta} =0.79 meV from {Delta} =1.17 meV at ambient pressure. The results allow us to predict a soft-mode quantum phase transition in this system at P{sub c} {approx} 4 GPa. The measurements are complicated by the proximity of a structural phase transition that leads to a deterioration of the sample.

Hong, Tao [ORNL; Garlea, Vasile O [ORNL; Zheludev, Andrey I [ORNL; Fernandez-Baca, Jaime A [ORNL; Manaka, H. [Kagoshima University, Kagoshima JAPAN; Chang, S. [National Institute of Standards and Technology (NIST); Leao, J. B. [National Institute of Standards and Technology (NIST); Poulton, S. J. [National Institute of Standards and Technology (NIST)

2008-01-01T23:59:59.000Z

371

Band filling effects on temperature performance of intermediate band quantum wire solar cells  

SciTech Connect (OSTI)

Detailed studies of solar cell efficiency as a function of temperature were performed for quantum wire intermediate band solar cells grown on the (311)A plane. A remotely doped one-dimensional intermediate band made of self-assembled In{sub 0.4}Ga{sub 0.6}As quantum wires was compared to an undoped intermediate band and a reference p-i-n GaAs sample. These studies indicate that the efficiencies of these solar cells depend on the population of the one-dimensional band by equilibrium free carriers. A change in this population by free electrons under various temperatures affects absorption and carrier transport of non-equilibrium carriers generated by incident light. This results in different efficiencies for both the doped and undoped intermediate band solar cells in comparison with the reference GaAs p-i-n solar cell device.

Kunets, Vas. P., E-mail: vkunets@uark.edu; Furrow, C. S.; Ware, M. E.; Souza, L. D. de; Benamara, M.; Salamo, G. J. [Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Mortazavi, M. [Department of Chemistry and Physics, University of Arkansas at Pine Bluff, Pine Bluff, Arkansas 71601 (United States)

2014-08-28T23:59:59.000Z

372

Correlation, relativistic, and quantum electrodynamics effects on the atomic structure of eka-thorium  

SciTech Connect (OSTI)

Large-scale multiconfiguration Dirac-Fock calculations have been performed for the superheavy element eka-thorium, Z=122. The resulting atomic structure is compared with that obtained by various computational approaches involving different degrees of approximation in order to elucidate the role that correlation, relativistic, Breit, and quantum electrodynamics corrections play in determining the low-energy atomic spectrum. The accuracy of the calculations is assessed by comparing theoretical results obtained for thorium with available experimental data.

Gaigalas, Gediminas; Gaidamauskas, Erikas; Rudzikas, Zenonas; Magnani, Nicola; Caciuffo, Roberto [Vilnius University Research Institute of Theoretical Physics and Astronomy, A. Gostauto 12, LT-01108 Vilnius (Lithuania); European Commission, Joint Research Centre, Institute for Transuranium Elements, Postfach 2340, D-76125 Karlsruhe (Germany)

2010-02-15T23:59:59.000Z

373

Dry Dilution Refrigerator for Experiments on Quantum Effects in the Microwave Regime  

E-Print Network [OSTI]

At the Walther-Mei{\\ss}ner-Institut (WMI), a new cryogen-free 3He/4He dilution refrigerator (DR) has been completed; the cryostat will be employed to cool experiments on superconducting quantum circuits for quantum information technology and quantum simulations. All major components have been made at the WMI. The DR offers lots of space at the various stages of the apparatus for microwave components and cables. E. g., the usable space at the mixing chamber has a height of more than 60 cm and a diameter of 30 cm (mixing chamber mounting plate). To cool cables and cold amplifiers, the DR is equipped with a separate 4He-1K-loop which offers a cooling power of up to 100 mW near 1K. The refrigeration power of the still is 18 mW at 0.9 K; the diameter of its mounting plate is 35 cm. The cryostat rests in an aluminum trestle on air springs to attenuate building vibrations. It is precooled by a Cryomech PT410-RM pulse tube cryocooler (PTC) which is mechanically decoupled from the vacuum can of the cryostat by a bello...

Marx, A; Uhlig, K

2014-01-01T23:59:59.000Z

374

Bernoulli's formula and Poisson's equations for a confined quantum gas: Effects due to a moving piston  

E-Print Network [OSTI]

We study a nonequilibrium equation of states of an ideal quantum gas confined in the cavity under a moving piston with a small but finite velocity in the case that the cavity wall suddenly begins to move at time origin. Confining to the thermally-isolated process, quantum non-adiabatic (QNA) contribution to Poisson's adiabatic equations and to Bernoulli's formula which bridges the pressure and internal energy is elucidated. We carry out a statistical mean of the non-adiabatic (time-reversal-symmetric) force operator found in our preceding paper (K. Nakamura et al, Phys. Rev. E Vol.83, 041133, (2011)) in both the low-temperature quantum-mechanical and high temperature quasi-classical regimes. The QNA contribution, which is proportional to square of the piston's velocity and to inverse of the longitudinal size of the cavity, has a coefficient dependent on temperature, gas density and dimensionality of the cavity. The investigation is done for a unidirectionally-expanding 3-d rectangular parallelepiped cavity as well as its 1-d version. Its relevance in a realistic nano-scale heat engine is discussed.

Katsuhiro Nakamura; Zarifboy A. Sobirov; Davron U. Matrasulov; Sanat K. Avazbaev

2012-12-25T23:59:59.000Z

375

Echo of the Quantum Bounce  

E-Print Network [OSTI]

We identify a signature of quantum gravitational effects that survives from the early universe to the current era: Fluctuations of quantum fields as seen by comoving observers are significantly influenced by the history of the early universe. In particular we show how the existence (or not) of a quantum bounce leaves a trace in the background quantum noise that is not damped and would be non-negligible even nowadays. Furthermore, we estimate an upper bound for the typical energy and length scales where quantum effects are relevant. We discuss how this signature might be observed and therefore used to build falsifiability tests of quantum gravity theories.

Luis J. Garay; Mercedes Martin-Benito; Eduardo Martin-Martinez

2014-02-15T23:59:59.000Z

376

On description of quantum plasma  

E-Print Network [OSTI]

A plasma becomes quantum when the quantum nature of its particles significantly affects its macroscopic properties. To answer the question of when the collective quantum plasma effects are important, a proper description of such effects is necessary. We consider here the most common methods of description of quantum plasma, along with the related assumptions and applicability limits. In particular, we analyze in detail the hydrodynamic description of quantum plasma, as well as discuss some kinetic features of analytic properties of linear dielectric response function in quantum plasma. We point out the most important, in our view, fundamental problems occurring already in the linear approximation and requiring further investigation. (submitted to Physics-Uspekhi)

S. V. Vladimirov; Yu. O. Tyshetskiy

2011-01-21T23:59:59.000Z

377

On the quantum effects on noncollinear Lagrangian points and displaced periodic orbits in the Earth-Moon system  

E-Print Network [OSTI]

Recent work in the literature has shown that the leading long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we discuss the prospects to measure, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. The present paper investigates therefore, eventually, a restricted three-body problem involving Earth, Moon and a solar sail. By taking into account the quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.

Emmanuele Battista; Simone Dell'Agnello; Giampiero Esposito; Jules Simo

2015-01-12T23:59:59.000Z

378

Spin-polarization and spin-dependent logic gates in a double quantum ring based on Rashba spin-orbit effect: Non-equilibrium Green's function approach  

SciTech Connect (OSTI)

Spin-dependent electron transport in an open double quantum ring, when each ring is made up of four quantum dots and threaded by a magnetic flux, is studied. Two independent and tunable gate voltages are applied to induce Rashba spin-orbit effect in the quantum rings. Using non-equilibrium Green's function formalism, we study the effects of electron-electron interaction on spin-dependent electron transport and show that although the electron-electron interaction induces an energy gap, it has no considerable effect when the bias voltage is sufficiently high. We also show that the double quantum ring can operate as a spin-filter for both spin up and spin down electrons. The spin-polarization of transmitted electrons can be tuned from ?1 (pure spin-down current) to +1 (pure spin-up current) by changing the magnetic flux and/or the gates voltage. Also, the double quantum ring can act as AND and NOR gates when the system parameters such as Rashba coefficient are properly adjusted.

Eslami, Leila, E-mail: Leslami@iust.ac.ir; Esmaeilzadeh, Mahdi, E-mail: mahdi@iust.ac.ir [Department of Physics, Iran University of Science and Technology, Tehran 16846 (Iran, Islamic Republic of)

2014-02-28T23:59:59.000Z

379

Quantum Thermometry  

E-Print Network [OSTI]

In this review article we revisit and spell out the details of previous work on how Berry phase can be used to construct a precision quantum thermometer. An important advantage of such a scheme is that there is no need for the thermometer to acquire thermal equilibrium with the sample. This reduces measurement times and avoids precision limitations. We also review how such methods can be used to detect the Unruh effect.

Robert B. Mann; Eduardo Martin-Martinez

2014-05-22T23:59:59.000Z

380

Building Codes for Classrooms 34MK 3401 Market Street JMHH Jon M. Huntsman Hall  

E-Print Network [OSTI]

Building Codes for Classrooms 34MK 3401 Market Street JMHH Jon M. Huntsman Hall 35MK 3550 Market Market Street KWH Kelly Writers House ACHM Anatomy/Chemistry Building L-FH Lauder-Fischer Hall ADDM Fisher-Bennett Hall LIPP Lippincott BLOC Blockley Hall LLAB Leidy Labs CAST Caster Building LRSM Lab

Plotkin, Joshua B.

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Buckled nano rod - a two state system: quantum effects on its dynamics  

E-Print Network [OSTI]

We consider a suspended elastic rod under longitudinal compression. The compression can be used to adjust potential energy for transverse displacements from harmonic to double well regime. The two minima in potential energy curve describe two possible buckled states. Using transition state theory (TST) we have calculated the rate of conversion from one state to other. If the strain $\\epsilon = 4 \\epsilon_c$ the simple TST rate diverges. We suggest a method to correct this divergence for quantum calculations. We also find that zero point energy contributions can be quite large so that single mode calculations can lead to large errors in the rate.

Aniruddha Chakraborty

2011-07-18T23:59:59.000Z

382

Effect of internal electric field on InAs/GaAs quantum dot solar cells  

SciTech Connect (OSTI)

We studied time-resolved carrier recombination in InAs/GaAs quantum dot (QD) solar cells. The electric field in a p-i-n diode structure spatially separates photoexcited carriers in QDs, strongly affecting the conversion efficiency of intermediate-band solar cells. The radiative decay lifetime is dramatically reduced in a strong electric field (193?kV/cm) by efficient recombination due to strong carrier localization in each QD and significant tunneling-assisted electron escape. Conversely, an electric field of the order of 10?kV/cm maintains electronic coupling in the stacked QDs and diminishes tunneling-assisted electron escape.

Kasamatsu, Naofumi; Kada, Tomoyuki; Hasegawa, Aiko; Harada, Yukihiro; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

2014-02-28T23:59:59.000Z

383

Underdamped quantum ratchets  

E-Print Network [OSTI]

We investigate the quantum ratchet effect under the influence of weak dissipation which we treat within a Floquet-Markov master equation approach. A ratchet current emerges when all relevant symmetries are violated. Using time-reversal symmetric driving we predict a purely dissipation-induced quantum ratchet current. This directed quantum transport results from bath-induced superpositions of non-transporting Floquet states.

S. Denisov; S. Kohler; P. Hanggi

2009-02-24T23:59:59.000Z

384

Micro-Hall position sensing of magnetic nanowires.  

SciTech Connect (OSTI)

The Hall voltage output of a micro-Hall magnetic sensor depends on the relative position of a magnetic nanowire with respect to its sensing area. Following this idea, we performed analytical calculations which show that, under certain conditions, these devices can track the position of a magnetic nanowire with subnanometer resolution. Our results suggest that micro-Hall sensors can be utilized to provide a direct electronic readout of the position of magnetic nanowires in their applications as biomolecular manipulators or dynamic components in micro- and nanoscale devices.

Mihajlovic, G.; Hoffmann, A.; von Molnar, S.; Materials Science Division; Florida State Univ.

2009-01-01T23:59:59.000Z

385

Development of multicomponent hybrid density functional theory with polarizable continuum model for the analysis of nuclear quantum effect and solvent effect on NMR chemical shift  

SciTech Connect (OSTI)

We have developed the multicomponent hybrid density functional theory [MC-(HF+DFT)] method with polarizable continuum model (PCM) for the analysis of molecular properties including both nuclear quantum effect and solvent effect. The chemical shifts and H/D isotope shifts of the picolinic acid N-oxide (PANO) molecule in chloroform and acetonitrile solvents are applied by B3LYP electron exchange-correlation functional for our MC-(HF+DFT) method with PCM (MC-B3LYP/PCM). Our MC-B3LYP/PCM results for PANO are in reasonable agreement with the corresponding experimental chemical shifts and isotope shifts. We further investigated the applicability of our method for acetylacetone in several solvents.

Kanematsu, Yusuke; Tachikawa, Masanori [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)] [Quantum Chemistry Division, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027 (Japan)

2014-04-28T23:59:59.000Z

386

Quantum confinement effects on the thermoelectric figure of merit in Si/Si{sub 1{minus}x}Ge{sub x} system  

SciTech Connect (OSTI)

The Si/Si{sub 1{minus}x}Ge{sub x} quantum well system is attractive for high temperature thermoelectric applications and for demonstration of proof-of-principle for enhanced thermoelectric figure of merit Z, since the interfaces and carrier densities can be well controlled in this system. The authors report here theoretical calculations for Z in this system, and results from theoretical modeling of quantum confinement effects in the presence of {delta}-doping within the barrier layers. The {delta}-doping layers are introduced by growing very thin layers of wide band gap materials within the barrier layers in order to increase the effective barrier height within the barriers and thereby reduce the barrier width necessary for the quantum confinement of carriers within the quantum well. The overall figure of merit is thereby enhanced due to the reduced barrier width and hence reduced thermal conductivity, {kappa}. The {delta}-doping should further reduce {kappa} in the barriers by introducing phonon scattering centers within the barrier region. The temperature dependence of Z for Si quantum wells is also discussed.

Sun, X.; Dresselhaus, M.S.; Wang, K.L.; Tanner, M.O.

1997-07-01T23:59:59.000Z

387

TBH-0042- In the Matter of Curtis Hall  

Broader source: Energy.gov [DOE]

This Initial Agency Decision involves a whistleblower complaint filed by Mr. Curtis Hall (also referred to as the complainant or the individual) under the Department of Energy (DOE) Contractor...

388

Theoretical and experimental investigation of Hall thruster miniaturization  

E-Print Network [OSTI]

Interest in small-scale space propulsion continues to grow with the increasing number of small satellite missions, particularly in the area of formation flight. Miniaturized Hall thrusters have been identified as a candidate ...

Warner, Noah Zachary, 1978-

2007-01-01T23:59:59.000Z

389

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New(19):4355-4364 Nidhi Sabharwal, Ph.D. Technology Manager Office of Technology Transfer (212) 327-7092 nsabharwal

390

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New, Ph.D. Technology Manager Office of Technology Transfer (212) 327-7092 nsabharwal@rockefeller.edu #12;

de Lange, Titia

391

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Sabharwal, Ph.D. Technology Manager Office of Technology Transfer (212) 327-7092 nsabharwal

392

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New,383,370. Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto

393

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New,049,814 · US Patent 8,553,143 Nidhi Sabharwal, Ph.D. Technology Manager Technology Transfer (212) 327

394

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;

395

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New.1016/j.jmb.2008.01.066 Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327

396

Innis Library Directory Kenneth Taylor Hall (KTH), Room 108  

E-Print Network [OSTI]

Innis Library Directory Kenneth Taylor Hall (KTH), Room 108 We may be small, but we've got it all, Directories, Encyclopedias, etc.] New Books Periodicals [Magazines & Newspapers] Bookstacks [A-HD] Group

Hitchcock, Adam P.

397

Norm G. Hall Western Australian Marine Research laboratories  

E-Print Network [OSTI]

Norm G. Hall Western Australian Marine Research laboratories Perth, Western Australia 6020, Western Australia. 61 50. Australia Ian C. Potter* School of Biological and Environmental Sciences, Murdoch University. Murdoch, Western Australia. 6 J50, Australia Comparisons between generalized growth

398

accelerator laboratory hall: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Halls Summer Residential Plasma Physics and Fusion Websites Summary: - youth playing sand volleyball or doing sidewalk chalk, picnic set-up at Adams or Ogg) ...and the most,000....

399

Quantum Black Holes Effects on the Shape of Extensive Air Showers  

E-Print Network [OSTI]

We investigate the possibility to find a characteristic TeV scale quantum black holes decay signature in the data recorded by cosmic rays experiments. TeV black holes can be produced via the collisions of ultra high energetic protons (E > $10^18$ eV) with nucleons the from atmosphere. We focus on the case when the black holes decay into two particles moving in the forward direction in the Earth reference frame (back-to-back in the center of mass reference frame) and induce two overlapping showers. When reconstructing both the energy and the shape of the resultant air shower, there is a significant difference between showers induced only via standard model interactions and showers produced via the back-to-back decay of black holes as intermediate states.

Nicusor Arsene; Lauretiu Ioan Caramete; Peter B. Denton; Octavian Micu

2014-07-08T23:59:59.000Z

400

Quantum Spacetime Phenomenology  

E-Print Network [OSTI]

I review the current status of phenomenological programs inspired by quantum-spacetime research. I stress in particular the significance of results establishing that certain data analyses provide sensitivity to effects introduced genuinely at the Planck scale. And my main focus is on phenomenological programs that managed to affect the directions taken by studies of quantum-spacetime theories.

Giovanni Amelino-Camelia

2013-06-18T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Quantum field theory in curved graphene spacetimes, Lobachevsky geometry, Weyl symmetry, Hawking effect, and all that  

E-Print Network [OSTI]

The solutions of many issues, of the ongoing efforts to make deformed graphene a tabletop quantum field theory in curved spacetimes, are presented. A detailed explanation of the special features of curved spacetimes, originating from embedding portions of the Lobachevsky plane into $\\mathbf{R}^3$, is given, and the special role of coordinates for the physical realizations in graphene, is explicitly shown, in general, and for various examples. The Rindler spacetime is reobtained, with new important differences with respect to earlier results. The de Sitter spacetime naturally emerges, for the first time, paving the way to future applications in cosmology. The role of the BTZ black hole is also briefly addressed. The singular boundary of the pseudospheres, "Hilbert horizon", is seen to be closely related to event horizon of the Rindler, de Sitter, and BTZ kind. This gives new, and stronger, arguments for the Hawking phenomenon to take place. An important geometric parameter, $c$, overlooked in earlier work, takes here its place for physical applications, and it is shown to be related to graphene's lattice spacing, $\\ell$. It is shown that all surfaces of constant negative curvature, ${\\cal K} = -r^{-2}$, are unified, in the limit $c/r \\to 0$, where they are locally applicable to the Beltrami pseudosphere. This, and $c = \\ell$, allow us a) to have a phenomenological control on the reaching of the horizon; b) to use spacetimes different than Rindler for the Hawking phenomenon; c) to approach the generic surface of the family. An improved expression for the thermal LDOS is obtained. A non-thermal term for the total LDOS is found. It takes into account: a) the peculiarities of the graphene-based Rindler spacetime; b) the finiteness of a laboratory surface; c) the optimal use of the Minkowski quantum vacuum, through the choice of this Minkowski-static boundary.

Alfredo Iorio; Gaetano Lambiase

2014-12-15T23:59:59.000Z

402

Time-domain detection of current controlled magnetization damping in Pt/Ni{sub 81}Fe{sub 19} bilayer and determination of Pt spin Hall angle  

SciTech Connect (OSTI)

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.

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

403

Quantum physics meets biology  

E-Print Network [OSTI]

Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the last decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world view of quantum coherences, entanglement and other non-classical effects, has been heading towards systems of increasing complexity. The present perspective article shall serve as a pedestrian guide to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future quantum biology, its current status, recent experimental progress and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.

Markus Arndt; Thomas Juffmann; Vlatko Vedral

2009-11-01T23:59:59.000Z

404

Photonic quantum technologies  

E-Print Network [OSTI]

The first quantum technology, which harnesses uniquely quantum mechanical effects for its core operation, has arrived in the form of commercially available quantum key distribution systems that achieve enhanced security by encoding information in photons such that information gained by an eavesdropper can be detected. Anticipated future quantum technologies include large-scale secure networks, enhanced measurement and lithography, and quantum information processors, promising exponentially greater computation power for particular tasks. Photonics is destined for a central role in such technologies owing to the need for high-speed transmission and the outstanding low-noise properties of photons. These technologies may use single photons or quantum states of bright laser beams, or both, and will undoubtably apply and drive state-of-the-art developments in photonics.

Jeremy L. O'Brien; Akira Furusawa; Jelena Vu?kovi?

2010-03-20T23:59:59.000Z

405

High-frequency Probing Diagnostic for Hall Current Plasma Thrusters  

SciTech Connect (OSTI)

High-frequency oscillations (1-100 MHz) in Hall thrusters have apparently eluded significant experimental scrutiny. A diagnostic setup, consisting of a single Langmuir probe, a special shielded probe connector-positioner, and an electronic impedance-matching circuit, was successfully built and calibrated. Through simultaneous high-frequency probing of the Hall thruster plasma at multiple locations, high-frequency plasma waves have been identified and characterized for various thruster operating conditions.

A.A. Litvak; Y. Raitses; N.J. Fisch

2001-10-25T23:59:59.000Z

406

Loop quantum gravity and observations  

E-Print Network [OSTI]

Quantum gravity has long been thought to be completely decoupled from experiments or observations. Although it is true that smoking guns are still missing, there are now serious hopes that quantum gravity phenomena might be tested. We review here some possible ways to observe loop quantum gravity effects either in the framework of cosmology or in astroparticle physics.

A. Barrau; J. Grain

2014-10-07T23:59:59.000Z

407

Photocurrent spectrum study of a quantum dot single-photon detector based on resonant tunneling effect with near-infrared response  

SciTech Connect (OSTI)

We present the photocurrent spectrum study of a quantum dot (QD) single-photon detector using a reset technique which eliminates the QD's “memory effect.” By applying a proper reset frequency and keeping the detector in linear-response region, the detector's responses to different monochromatic light are resolved which reflects different detection efficiencies. We find the reset photocurrent tails up to 1.3??m wavelength and near-infrared (?1100?nm) single-photon sensitivity is demonstrated due to interband transition of electrons in QDs, indicating the device a promising candidate both in quantum information applications and highly sensitive imaging applications operating in relative high temperatures (>80?K).

Weng, Q. C. [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); An, Z. H., E-mail: anzhenghua@fudan.edu.cn, E-mail: luwei@mail.sitp.ac.cn [State Key Laboratory of Surface Physics and Institute of Advanced Materials, Fudan University, Shanghai 200433 (China); Xiong, D. Y.; Zhu, Z. Q. [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); Zhang, B.; Chen, P. P.; Li, T. X.; Lu, W., E-mail: anzhenghua@fudan.edu.cn, E-mail: luwei@mail.sitp.ac.cn [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

2014-07-21T23:59:59.000Z

408

Coupled-channels density-matrix approach to low-energy nuclear collision dynamics: A technique for quantifying quantum decoherence effects on reaction observables  

E-Print Network [OSTI]

The coupled-channels density-matrix technique for nuclear reaction dynamics, which is based on the Liouville-von Neumann equation with Lindblad dissipative terms, is developed with the inclusion of full angular momentum couplings. It allows a quantitative study of the role and importance of quantum decoherence in nuclear scattering. Formulae of asymptotic observables that can reveal effects of quantum decoherence are given. A method for extracting energy-resolved scattering information from the time-dependent density matrix is introduced. As an example, model calculations are carried out for the low-energy collision of the $^{16}$O projectile on the $^{154}$Sm target.

Alexis Diaz-Torres

2010-10-18T23:59:59.000Z

409

SECTION 6-RESIDENCE HALL SAFETY Safety for residents, staff, and visitors to the residence halls is the responsibility of the Residential Life  

E-Print Network [OSTI]

halls is the responsibility of the Residential Life Department. The department reports unsafe hazards for the purpose of insuring a safe residential environment administered by Residential Life shall be as follows: SAFETY INSPECTIONS OF RESIDENT HALLS Residential Hall rooms shall be inspected monthly for fire safety

Selmic, Sandra

410

Strong reactions in quantum super PDEs. III: Exotic quantum supergravity  

E-Print Network [OSTI]

Following the previous two parts, of a work devoted to encode strong reaction dynamics in the A. Pr\\'astaro's algebraic topology of quantum super PDE's, nonlinear quantum propagators in the observed quantum super Yang-Mills PDE, $\\hat{(YM)}[i]$, are further characterized. In particular, nonlinear quantum propagators with non-zero defect quantum electric-charge, are interpreted as {\\em exotic-quantum supergravity} effects. As an application, the recently discovered bound-state called $Zc(3900)$, is obtained as a neutral quasi-particle, generated in a $Q$-quantum exotic supergravity process. {\\em Quantum entanglement} is justified by means of the algebraic topologic structure of nonlinear quantum propagators. Quantum Cheshire cats are considered as examples of quantum entanglements. Existence theorem for solutions of $\\hat{(YM)}[i]$ admitting negative local temperatures ({\\em quantum thermodynamic-exotic solutions}) is obtained too and related to quantum entanglement. Such exotic solutions are used to encode Universe at the Planck-epoch. It is proved that the Universe's expansion at the Planck epoch is justified by the fact that it is encoded by a nonlinear quantum propagator having thermodynamic quantum exotic components in its boundary. This effect produces also an increasing of energy in the Universe at the Einstein epoch: {\\em Planck-epoch-legacy} on the boundary of our Universe. This is the main source of the Universe's expansion and solves the problem of the non-apparent energy-matter ({\\em dark-energy-matter}) in the actual Universe. Breit-Wheeler-type processes have been proved in the framework of the Pr\\'astaro's algebraic topology of quantum super Yang-Mills PDEs. Numerical comparisons of nonlinear quantum propagators with Weinberg-Salam electroweak theory in Standard Model are given.

Agostino Prástaro

2015-03-23T23:59:59.000Z

411

Strong reactions in quantum super PDEs. III: Exotic quantum supergravity  

E-Print Network [OSTI]

Following the previous two parts, of a work devoted to encode strong reaction dynamics in the A. Pr\\'astaro's algebraic topology of quantum super PDE's, nonlinear quantum propagators in the observed quantum super Yang-Mills PDE, $\\hat{(YM)}[i]$, are further characterized. In particular, nonlinear quantum propagators with non-zero defect quantum electric-charge, are interpreted as {\\em exotic-quantum supergravity} effects. As an application, the recently discovered bound-state called $Zc(3900)$, is obtained as a neutral quasi-particle, generated in a $Q$-quantum exotic supergravity process. {\\em Quantum entanglement} is justified by means of the algebraic topologic structure of nonlinear quantum propagators. Quantum Cheshire cats are considered as examples of quantum entanglements. Existence theorem for solutions of $\\hat{(YM)}[i]$ admitting negative local temperatures ({\\em quantum thermodynamic-exotic solutions}) is obtained too and related to quantum entanglement. Such exotic solutions are used to encode Universe at the Planck-epoch. It is proved that the Universe's expansion at the Planck epoch is justified by the fact that it is encoded by a nonlinear quantum propagator having thermodynamic quantum exotic components in its boundary. This effect produces also an increasing of energy in the Universe at the Einstein epoch: {\\em Planck-epoch-legacy} on the boundary of our Universe. This is the main source of the Universe's expansion and solves the problem of the non-apparent energy-matter ({\\em dark-energy-matter}) in the actual Universe. Breit-Wheeler-type processes have been proved in the framework of the Pr\\'astaro's algebraic topology of quantum super Yang-Mills PDEs. Numerical comparisons of nonlinear quantum propagators with Weinberg-Salam electroweak theory in Standard Model are given.

Agostino Prástaro

2015-02-01T23:59:59.000Z

412

Strong reactions in quantum super PDEs. III: Exotic quantum supergravity  

E-Print Network [OSTI]

Following the previous two parts, of a work devoted to encode strong reaction dynamics in the A. Pr\\'astaro's algebraic topology of quantum super PDE's, nonlinear quantum propagators in the observed quantum super Yang-Mills PDE, $\\hat{(YM)}[i]$, are further characterized. In particular, nonlinear quantum propagators with non-zero defect quantum electric-charge, are interpreted as {\\em exotic-quantum supergravity} effects. As an application, the recently discovered bound-state called $Zc(3900)$, is obtained as a neutral quasi-particle, generated in a $Q$-quantum exotic supergravity process. {\\em Quantum entanglement} is justified by means of the algebraic topologic structure of nonlinear quantum propagators. Quantum Cheshire cats are considered as examples of quantum entanglements. Existence theorem for solutions of $\\hat{(YM)}[i]$ admitting negative local temperatures ({\\em quantum thermodynamic-exotic solutions}) is obtained too and related to quantum entanglement. Such exotic solutions are used to encode Universe at the Planck-epoch. It is proved that the Universe's expansion at the Planck epoch is justified by the fact that it is encoded by a nonlinear quantum propagator having thermodynamic quantum exotic components in its boundary. This effect produces also an increasing of energy in the Universe at the Einstein epoch: {\\em Planck-epoch-legacy} on the boundary of our Universe. This is the main source of the Universe's expansion and solves the problem of the non-apparent energy-matter ({\\em dark-energy-matter}) in the actual Universe. Breit-Wheeler-type processes have been proved in the framework of the Pr\\'astaro's algebraic topology of quantum super Yang-Mills PDEs. Numerical comparisons of nonlinear quantum propagators with Weinberg-Salam electroweak theory in Standard Model are given.

Agostino Prástaro

2015-03-10T23:59:59.000Z

413

Quantum Simulation  

E-Print Network [OSTI]

Simulating quantum mechanics is known to be a difficult computational problem, especially when dealing with large systems. However, this difficulty may be overcome by using some controllable quantum system to study another less controllable or accessible quantum system, i.e., quantum simulation. Quantum simulation promises to have applications in the study of many problems in, e.g., condensed-matter physics, high-energy physics, atomic physics, quantum chemistry and cosmology. Quantum simulation could be implemented using quantum computers, but also with simpler, analog devices that would require less control, and therefore, would be easier to construct. A number of quantum systems such as neutral atoms, ions, polar molecules, electrons in semiconductors, superconducting circuits, nuclear spins and photons have been proposed as quantum simulators. This review outlines the main theoretical and experimental aspects of quantum simulation and emphasizes some of the challenges and promises of this fast-growing field.

I. M. Georgescu; S. Ashhab; Franco Nori

2014-03-13T23:59:59.000Z

414

Structural and orientation effects on electronic energy transfer between silicon quantum dots with dopants and with silver adsorbates  

SciTech Connect (OSTI)

Starting from the atomic structure of silicon quantum dots (QDs), and utilizing ab initio electronic structure calculations within the Förster resonance energy transfer (FRET) treatment, a model has been developed to characterize electronic excitation energy transfer between QDs. Electronic energy transfer rates, K{sub EET}, between selected identical pairs of crystalline silicon quantum dots systems, either bare, doped with Al or P, or adsorbed with Ag and Ag{sub 3}, have been calculated and analyzed to extend previous work on light absorption by QDs. The effects of their size and relative orientation on energy transfer rates for each system have also been considered. Using time-dependent density functional theory and the hybrid functional HSE06, the FRET treatment was employed to model electronic energy transfer rates within the dipole-dipole interaction approximation. Calculations with adsorbed Ag show that: (a) addition of Ag increases rates up to 100 times, (b) addition of Ag{sub 3} increases rates up to 1000 times, (c) collinear alignment of permanent dipoles increases transfer rates by an order of magnitude compared to parallel orientation, and (d) smaller QD-size increases transfer due to greater electronic orbitals overlap. Calculations with dopants show that: (a) p-type and n-type dopants enhance energy transfer up to two orders of magnitude, (b) surface-doping with P and center-doping with Al show the greatest rates, and (c) K{sub EET} is largest for collinear permanent dipoles when the dopant is on the outer surface and for parallel permanent dipoles when the dopant is inside the QD.

Vinson, N.; Freitag, H.; Micha, D. A., E-mail: micha@qtp.ufl.edu [Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611 (United States)

2014-06-28T23:59:59.000Z

415

Quantum optics and cavity QED with quantum dots in photonic crystals  

E-Print Network [OSTI]

This chapter will primarily focus on the studies of quantum optics with semiconductor, epitaxially grown quantum dots embedded in photonic crystal cavities. We will start by giving brief introductions into photonic crystals and quantum dots, then proceed with the introduction to cavity quantum electrodynamics (QED) effects, with a particular emphasis on the demonstration of these effects on the quantum dot-photonic crystal platform. Finally, we will focus on the applications of such cavity QED effects.

Jelena Vuckovic

2014-02-11T23:59:59.000Z

416

Systematic relativistic quantum effects on screening of fusion rates in white dwarfs  

E-Print Network [OSTI]

Relativistic electron degeneracy effects are dominant in ultra-dense plasmas (UDP), such as those found in white dwarfs. These effects can be treated systematically by obtaining an expansion of the screening length in inverse powers of $\\hbar^{2}$. In general, our theory leads to an ${\\cal O}(10)$ effect on the enhancement of fusion rates in white dwarfs. Further, it is shown analytically for these stellar conditions that Bose statistics of nuclei have a negligible effect on the screening length, in consonance with Monte Carlo simulations found in literature.

Shirish M. Chitanvis

2006-11-21T23:59:59.000Z

417

Systematic quantum effects on screening of fusion rates in white dwarfs  

E-Print Network [OSTI]

Electron degeneracy effects are dominant in ultra-dense plasmas (UDP), such as those found in white dwarfs. These effects can be treated systematically by obtaining an expansion of the screening length in inverse powers of $\\hbar^{2}$. The theory exhibits Thomas-Fermi-like screening in an appropriate regime. In general, our theory leads to an ${\\cal O}(1)$ effect on the enhancement of fusion rates in white dwarfs. Further, it is shown analytically for these stellar conditions that Bose statistics of nuclei have a negligible effect on the screening length, in consonance with Monte Carlo simulations found in literature.

Shirish M. Chitanvis

2006-10-19T23:59:59.000Z

418

Classical and Quantum Polyhedra  

E-Print Network [OSTI]

Quantum polyhedra constructed from angular momentum operators are the building blocks of space in its quantum description as advocated by Loop Quantum Gravity. Here we extend previous results on the semiclassical properties of quantum polyhedra. Regarding tetrahedra, we compare the results from a canonical quantization of the classical system with a recent wave function based approach to the large-volume sector of the quantum system. Both methods agree in the leading order of the resulting effective operator (given by an harmonic oscillator), while minor differences occur in higher corrections. Perturbative inclusion of such corrections improves the approximation to the eigenstates. Moreover, the comparison of both methods leads also to a full wave function description of the eigenstates of the (square of the) volume operator at negative eigenvalues of large modulus. For the case of general quantum polyhedra described by discrete angular momentum quantum numbers we formulate a set of quantum operators fulfilling in the semiclassical regime the standard commutation relations between momentum and position. Differently from previous formulations, the position variable here is chosen to have dimension of (Planck) length squared which facilitates the identification of quantum corrections. Finally, we provide expressions for the pentahedral volume in terms of Kapovich-Millson variables.

John Schliemann

2014-12-11T23:59:59.000Z

419

Nonlinear Quantum Gravity  

E-Print Network [OSTI]

Nonlinear quantum mechanics at the Planck scale can produce nonlocal effects contributing to resolution of singularities, to cosmic acceleration, and modified black-hole dynamics, while avoiding the usual causality issues.

George Svetlichny

2006-02-01T23:59:59.000Z

420

Tunnel determinants from spectral zeta functions. Instanton effects in quantum mechanics  

SciTech Connect (OSTI)

In this paper we develop an spectral zeta function regularization procedure on the determinants of instanton fluctuation operators that describe the semi-classical order of tunnel effects between degenerate vacua.

Izquierdo, A. Alonso [Departamento de Matematica Aplicada and IUFFyM, Universidad de Salamanca (Spain); Guilarte, J. Mateos [Departamento de Fisica Fundamental and IUFFyM, Universidad de Salamanca (Spain)

2014-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
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421

PUBLISHED ONLINE: 13 JUNE 2010 | DOI: 10.1038/NPHYS1697 Measurement of the effect of quantum phase slips  

E-Print Network [OSTI]

of quantum phase slips in a Josephson junction chain I. M. Pop1 , I. Protopopov2,3 , F. Lecocq1 , Z. Peng1 transition, as has been observed in thin superconduct- ing films5,6 , wires7 and also in Josephson junction in the ground state of a Josephson junction chain. We tune in situ the strength of quantum phase fluctuations

Loss, Daniel

422

The spin Hall angle and spin diffusion length of Pd measured by spin pumping and microwave photoresistance  

SciTech Connect (OSTI)

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.

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

423

Quantum Machines  

E-Print Network [OSTI]

We discuss quantum information processing machines. We start with single purpose machines that either redistribute quantum information or identify quantum states. We then move on to machines that can perform a number of functions, with the function they perform being determined by a program, which is itself a quantum state. Examples of both deterministic and probabilistic programmable machines are given, and we conclude with a discussion of the utility of quantum programs.

Mark Hillery; Vladimir Buzek

2009-03-24T23:59:59.000Z

424

Semiclassical analysis of quantum dynamics  

E-Print Network [OSTI]

Simulating the molecular dynamics (MD) using classical or semi-classical trajectories provides important details for the understanding of many chemical reactions, protein folding, drug design, and solvation effects. MD simulations using trajectories have achieved great successes in the computer simulations of various systems, but it is difficult to incorporate quantum effects in a robust way. Therefore, improving quantum wavepacket dynamics and incorporating nonadiabatic transitions and quantum effects into classical and semi-classical molecular dynamics is critical as well as challenging. In this paper, we present a MD scheme in which a new set of equations of motion (EOM) are proposed to effectively propagate nuclear trajectories while conserving quantum mechanical energy which is critical for describing quantum effects like tunneling. The new quantum EOM is tested on a one-state one-dimensional and a two-state two-dimensional model nonadiabatic systems. The global quantum force experienced by each trajectory promotes energy redistribution among the bundle of trajectories, and thus helps the individual trajectory tunnel through the potential barrier higher than the energy of the trajectory itself. Construction of the new quantum force and EOM also provides a better way to treat the issue of back-reaction in mixed quantum-classical (MQC) methods, i.e. self-consistency between quantum degrees of freedom (DOF) and classical DOF.

Siyang Yang

2011-11-15T23:59:59.000Z

425

Studies of Novel Quantum Phenomena in Ruthenates  

SciTech Connect (OSTI)

Strongly correlated oxides have been the subject of intense study in contemporary condensed matter physics, and perovskite ruthenates (Sr,Ca)n+1RunO3n+1 have become a new focus in this field. One of important characteristics of ruthenates is that both lattice and orbital degrees of freedom are active and are strongly coupled to charge and spin degrees of freedom. Such a complex interplay of multiple degrees of freedom causes the properties of ruthenates to exhibit a gigantic response to external stimuli under certain circumstances. Magnetic field, pressure, and chemical composition all have been demonstrated to be effective in inducing electronic/magnetic phase transitions in ruthenates. Therefore, ruthenates are ideal candidates for searching for novel quantum phenomena through controlling external parameters. The objective of this project is to search for novel quantum phenomena in ruthenate materials using high-quality single crystals grown by the floating-zone technique, and investigate the underlying physics. The following summarizes our accomplishments. We have focused on trilayered Sr4Ru3O10 and bilayered (Ca1-xSrx)3Ru2O7. We have succeeded in growing high-quality single crystals of these materials using the floating-zone technique and performed systematic studies on their electronic and magnetic properties through a variety of measurements, including resistivity, Hall coefficient, angle-resolved magnetoresistivity, Hall probe microscopy, and specific heat. We have also studied microscopic magnetic properties for some of these materials using neutron scattering in collaboration with Los Alamos National Laboratory. We have observed a number of unusual exotic quantum phenomena through these studies, such as an orbital selective metamagnetic transition, bulk spin valve effect, and a heavy-mass nearly ferromagnetic state with a surprisingly large Wilson ratio. Our work has also revealed underlying physics of these exotic phenomena. Exotic phenomena of correlated electron has been among central topics of contempary condensed matter physics. Ultrfast phase transitions accompanied by switching of conductivity or magnetization in stronly correlated materials are believed to be promising in developing next generation of transistors. Our work on layered ruthenates has remarkably advanced our understanding of how the exotic phenomena of correlated electrons is governed by the complex interplay between charge, spin, lattice and orbital degrees of freedom. In addition to studies on ruthenates, we have also expanded our research to the emerging field of Fe-based superconductors, focusing on the iron chalcogenide Fe1+y(Te1-xSex) superconductor system. We first studied the superconductivity of this alloy system following the discovery of superconductivity in FeSe using polycrystalline samples. Later, we successfuly grew high-quality single crystals of these materials. Using these single crystals, we have determined the magnetic structure of the parent compound Fe1+yTe, observed spin resonance of superconducting state in optimally doped samples, and established a phase diagram. Our work has produced an important impact in this burgeoning field. The PI presented an invited talk on this topic at APS March meeting in 2010. We have published 19 papers in these two areas (one in Nature materials, five in Physical Review Letters, and nine in Physical Review B) and submitted two (see the list of publications attached below).

Mao, Zhiqiang

2011-04-08T23:59:59.000Z

426

Fundamental Difference between the Two Variants of Hall Thrusters: SPT and TAL  

E-Print Network [OSTI]

, 3]. At this early date in its history, the device was simply called a Hall current ion accel- erator magnetic field and typical particle trajectories. a substantial resurge in interest[12] in Hall thrusters

Choueiri, Edgar

427

The effect of photo-generated carriers on the spectral diffusion of a quantum dot coupled to a photonic crystal cavity  

E-Print Network [OSTI]

We experimentally observe the effect of photo-generated carriers on the spectral diffusion of a quantum dot (QD) coupled to a photonic crystal (PC) cavity. In this system, spectral diffusion arises in part from charge fluctuations on the etched surfaces of the PC. We find that these fluctuations may be suppressed by photo-generated carriers, leading to a reduction of the measured QD linewidth by a factor of ~2 compared to the case where the photo-generated carriers are not present. This result demonstrates a possible means of countering the effects of spectral diffusion in QD-PC cavity systems and thus may be useful for quantum information applications where narrow QD linewidths are desired.

Arka Majumdar; Erik D. Kim; Jelena Vuckovic

2011-07-24T23:59:59.000Z

428

Why do mixed quantum-classical methods describe short-time dynamics through conical intersections so well? Analysis of geometric phase effects  

E-Print Network [OSTI]

Adequate simulation of non-adiabatic dynamics through conical intersection requires account for a non-trivial geometric phase (GP) emerging in electronic and nuclear wave-functions in the adiabatic representation. Popular mixed quantum-classical (MQC) methods, surface hopping and Ehrenfest, do not carry a nuclear wave-function to be able to incorporate the GP into nuclear dynamics. Surprisingly, the MQC methods reproduce ultra-fast interstate crossing dynamics generated with the exact quantum propagation so well as if they contained information about the GP. Using two-dimensional linear vibronic coupling models we unravel how the MQC methods can effectively mimic the most significant dynamical GP effects: 1) compensation for repulsive diagonal second order non-adiabatic couplings and 2) transfer enhancement for a fully cylindrically symmetric component of a nuclear distribution.

Gherib, Rami; Izmaylov, Artur F

2015-01-01T23:59:59.000Z

429

The Quantum Frontier  

E-Print Network [OSTI]

The success of the abstract model of computation, in terms of bits, logical operations, programming language constructs, and the like, makes it easy to forget that computation is a physical process. Our cherished notions of computation and information are grounded in classical mechanics, but the physics underlying our world is quantum. In the early 80s researchers began to ask how computation would change if we adopted a quantum mechanical, instead of a classical mechanical, view of computation. Slowly, a new picture of computation arose, one that gave rise to a variety of faster algorithms, novel cryptographic mechanisms, and alternative methods of communication. Small quantum information processing devices have been built, and efforts are underway to build larger ones. Even apart from the existence of these devices, the quantum view on information processing has provided significant insight into the nature of computation and information, and a deeper understanding of the physics of our universe and its connections with computation. We start by describing aspects of quantum mechanics that are at the heart of a quantum view of information processing. We give our own idiosyncratic view of a number of these topics in the hopes of correcting common misconceptions and highlighting aspects that are often overlooked. A number of the phenomena described were initially viewed as oddities of quantum mechanics. It was quantum information processing, first quantum cryptography and then, more dramatically, quantum computing, that turned the tables and showed that these oddities could be put to practical effect. It is these application we describe next. We conclude with a section describing some of the many questions left for future work, especially the mysteries surrounding where the power of quantum information ultimately comes from.

Joseph F. Fitzsimons; Eleanor G. Rieffel; Valerio Scarani

2013-06-16T23:59:59.000Z

430

Anisotropic strain effects on the photoluminescence emission from heteroepitaxial and homoepitaxial nonpolar (Zn,Mg)O/ZnO quantum wells  

SciTech Connect (OSTI)

We report on the properties of nonpolar a-plane (Zn,Mg)O/ZnO quantum wells (QW) grown by molecular beam epitaxy on r plane sapphire and a plane ZnO substrates. For the QWs grown on sapphire, the anisotropy of the lattice parameters of the (Zn,Mg)O barrier gives rise to an unusual in-plane strain state in the ZnO QWs, which induces a strong blue-shift of the excitonic transitions, in addition to the confinement effects. We observe this blue-shift in photoluminescence excitation experiments. The photoluminescence excitation energies of the QWs are satisfactorily simulated when taking into account the variation of the exciton binding energy with the QW width and the residual anisotropic strain. Then we compare the photoluminescence properties of homoepitaxial QWs grown on ZnO bulk substrate and heteroepitaxial QWs grown on sapphire. We show that the reduction of structural defects and the improvement of surface morphology are correlated with a strong enhancement of the photoluminescence properties: reduction of full width at half maximum, strong increase of the luminescence intensities. The comparison convincingly demonstrates the interest of homoepitaxial nonpolar QWs for bright UV emission applications.

Chauveau, J.-M.; Vinter, B. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Teisseire, M.; Morhain, C.; Deparis, C. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique (CRHEA-CNRS), Rue B. Gregory, F-06560 Valbonne Sophia Antipolis (France); Kim-Chauveau, H.

2011-05-15T23:59:59.000Z

431

Reconnection events in two-dimensional Hall magnetohydrodynamic turbulence  

SciTech Connect (OSTI)

The statistical study of magnetic reconnection events in two-dimensional turbulence has been performed by comparing numerical simulations of magnetohydrodynamics (MHD) and Hall magnetohydrodynamics (HMHD). The analysis reveals that the Hall term plays an important role in turbulence, in which magnetic islands simultaneously reconnect in a complex way. In particular, an increase of the Hall parameter, the ratio of ion skin depth to system size, broadens the distribution of reconnection rates relative to the MHD case. Moreover, in HMHD the local geometry of the reconnection region changes, manifesting bifurcated current sheets and quadrupolar magnetic field structures in analogy to laminar studies, leading locally to faster reconnection processes in this case of reconnection embedded in turbulence. This study supports the idea that the global rate of energy dissipation is controlled by the large scale turbulence, but suggests that the distribution of the reconnection rates within the turbulent system is sensitive to the microphysics at the reconnection sites.

Donato, S.; Servidio, S.; Carbone, V. [Dipartimento di Fisica, Universita della Calabria, I-87036 Cosenza (Italy); Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Fisica de Buenos Aires, CONICET, Buenos Aires (Argentina); Shay, M. A.; Matthaeus, W. H. [Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Cassak, P. A. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2012-09-15T23:59:59.000Z

432

AC transport in p-Ge/GeSi quantum well in high magnetic fields  

SciTech Connect (OSTI)

The contactless surface acoustic wave technique is implemented to probe the high-frequency conductivity of a high-mobility p-Ge/GeSi quantum well structure in the regime of integer quantum Hall effect (IQHE) at temperatures 0.3–5.8 K and magnetic fields up to 18 T. It is shown that, in the IQHE regime at the minima of conductivity, holes are localized and ac conductivity is of hopping nature and can be described within the “two-site” model. The analysis of the temperature and magnetic-field-orientation dependence of the ac conductivity at odd filing factors enables us to determine the effective hole g-factor, |g{sub zz}|?4.5. It is shown that the in-plane component of the magnetic field leads to a decrease in the g-factor as well as increase in the cyclotron mass, which is explained by orbital effects in the complex valence band of germanium.

Drichko, I. L.; Malysh, V. A.; Smirnov, I. Yu.; Golub, L. E.; Tarasenko, S. A. [A.F. Ioffe Physical Technical Institute of Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Suslov, A. V. [National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States); Mironov, O. A. [Warwick SEMINANO R and D Center, University of Warwick Science Park, Coventry CV4 7EZ (United Kingdom); Kummer, M.; Känel, H. von [Laboratorium für Festkörperphysik ETH Zürich, CH-8093 Zürich (Switzerland)

2014-08-20T23:59:59.000Z

433

Optical Stark Effect and Dressed Exciton States in a Mn-Doped CdTe Quantum Dot C. Le Gall,1  

E-Print Network [OSTI]

Optical Stark Effect and Dressed Exciton States in a Mn-Doped CdTe Quantum Dot C. Le Gall,1 A spin in a CdTe QD, like the strain- induced magnetic anisotropy or hyperfine coupling to the nuclei in this study is grown on a ZnTe substrate and contains CdTe QDs. A 6.5 monolayer thick CdTe layer is deposited

Boyer, Edmond

434

Nuclear quantum effects on the structure and the dynamics of [H{sub 2}O]{sub 8} at low temperatures  

SciTech Connect (OSTI)

We use ring-polymer-molecular-dynamics (RPMD) techniques and the semi-empirical q-TIP4P/F water model to investigate the relationship between hydrogen bond connectivity and the characteristics of nuclear position fluctuations, including explicit incorporation of quantum effects, for the energetically low lying isomers of the prototype cluster [H{sub 2}O]{sub 8} at T = 50 K and at 150 K. Our results reveal that tunneling and zero-point energy effects lead to sensible increments in the magnitudes of the fluctuations of intra and intermolecular distances. The degree of proton spatial delocalization is found to map logically with the hydrogen-bond connectivity pattern of the cluster. Dangling hydrogen bonds exhibit the largest extent of spatial delocalization and participate in shorter intramolecular O-H bonds. Combined effects from quantum and polarization fluctuations on the resulting individual dipole moments are also examined. From the dynamical side, we analyze the characteristics of the infrared absorption spectrum. The incorporation of nuclear quantum fluctuations promotes red shifts and sensible broadening relative to the classical profile, bringing the simulation results in much more satisfactory agreement with direct experimental information in the mid and high frequency range of the stretching band. While RPMD predictions overestimate the peak position of the low frequency shoulder, the overall agreement with that reported using an accurate, parameterized, many-body potential is reasonable, and far superior to that one obtains by implementing a partially adiabatic centroid molecular dynamics approach. Quantum effects on the collective dynamics, as reported by instantaneous normal modes, are also discussed.

Videla, Pablo E. [Departamento de Química Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires (Argentina)] [Departamento de Química Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires (Argentina); Rossky, Peter J. [Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712-0165 (United States)] [Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712-0165 (United States); Laria, D., E-mail: dhlaria@cnea.gov.ar [Departamento de Química Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires (Argentina); Departamento de Física de la Materia Condensada, Comisión Nacional de Energía Atómica, Avenida Libertador 8250, 1429 Buenos Aires (Argentina)

2013-11-07T23:59:59.000Z

435

Coherent effects in atomic and molecular media: applications to anthrax detection and quantum information  

E-Print Network [OSTI]

Equation for Photon Number . . . . . . . . . . . . 179 C. Methods of Creating rhobc . . . . . . . . . . . . . . . . . . . 186 1. Quasi CW Injection Model . . . . . . . . . . . . . . . 187 2. Oblique Propagation of Atomic Beam in the Mi- crowave Cavity... formulation [8]. While by using Maxwell?s equations, we simulated the propagation of all four pulses in the medium, in ad- dition to the non-linear interaction, for different optical densities. All propagation effects where accounted for including pump...

Sariyanni, Zoe-Elizabeth

2006-10-30T23:59:59.000Z

436

Spectroscopy of snake states using a graphene Hall bar  

SciTech Connect (OSTI)

An approach to observe snake states in a graphene Hall bar containing a pn-junction is proposed. The magnetic field dependence of the bend resistance in a ballistic graphene Hall bar structure containing a tilted pn-junction oscillates as a function of applied magnetic field. We show that each oscillation is due to a specific snake state that moves along the pn-interface. Furthermore, depending on the value of the magnetic field and applied potential, we can control the lead in which the electrons will end up and hence control the response of the system.

Milovanovi?, S. P., E-mail: slavisa.milovanovic@gmail.com; Ramezani Masir, M., E-mail: mrmphys@gmail.com; Peeters, F. M., E-mail: francois.peeters@ua.ac.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)

2013-12-02T23:59:59.000Z

437

PHYSICAL REVIEW A 81, 062317 (2010) Resources required for topological quantum factoring  

E-Print Network [OSTI]

apply Bravyi's distillation method [S. Bravyi, Phys. Rev. A 73, 042313 (2006)] which combines Fibonacci anyons versus at least 3 × 109 Ising anyons. Other distillation algorithms could reduce. Ising anyons are expected to be the excitations of the = 5/2 fractional quantum Hall state [4

Bonesteel, Nicholas E.

2010-01-01T23:59:59.000Z

438

PUBLICATIONS OF CHARLES A.S. HALL {Chronological} as of October 2012. Books are in bold.  

E-Print Network [OSTI]

-21. 12. Hall, C.A.S. 1975. Models and the decision-making process: The Hudson River power plant case Productivity of the Biosphere. Springer-Verlag, New York. 15. (Review) Hall, C.A.S. 1975. Electric Power Plants.A. and C.A.S. Hall. 1972. Systems Analysis and Simulation in Ecology, Vol. 1 edited by B.C. Patten

Hall, Charles A.S.

439

HIGH ACCURACY BEAM CURRENT MONITOR SYSTEM FOR CEBAF'S EXPERIMENTAL HALL A *  

E-Print Network [OSTI]

HIGH ACCURACY BEAM CURRENT MONITOR SYSTEM FOR CEBAF'S EXPERIMENTAL HALL A * J.-C. Denard , A. Saha CEBAF accelerator delivers continuous wave (CW) electron beams to three experimental Halls. In Hall A is described. 1 INTRODUCTION The CEBAF accelerator delivers continuous wave (CW) electron beams to three

440

THE NEW VME-BASED SYSTEM FOR MAGNETIC MEASUREMENTS WITH HALL SENSORS  

E-Print Network [OSTI]

THE NEW VME-BASED SYSTEM FOR MAGNETIC MEASUREMENTS WITH HALL SENSORS A.Batrakov, S.Zverev, I, 630090, Russia Abstract Systems with Hall sensors are widely used for magnetic measurements. The paper for creation of measuring systems with Hall sensors in BINP for many years [1]. These systems had good

Kozak, Victor R.

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Page 28 Housing Services Sonoma State University 2012-2013 Catalog Zinfandel Hall  

E-Print Network [OSTI]

its own dining hall, swimming pools, study rooms, convenience store, post office, meeting roomsPage 28 Housing Services Sonoma State University 2012-2013 Catalog Zinfandel Hall (707) 664. The Community is a unique mix of nontraditional resident hall suites and campus apartments, all located just

Ravikumar, B.

442

Page 28 Housing Services Sonoma State University 2011-2012 Catalog Zinfandel Hall  

E-Print Network [OSTI]

its own dining hall, swimming pools, study rooms, convenience store, post office, meeting roomsPage 28 Housing Services Sonoma State University 2011-2012 Catalog Zinfandel Hall (707) 664. The Community is a unique mix of nontraditional resident hall suites and campus apartments, all located just

Ravikumar, B.

443

Effect of Ligands on Characteristics of (CdSe)13 Quantum Dot. | EMSL  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series toESnet4: Networking for the FutureEdward Teller Medals Under theEffect of

444

Quantum robots and quantum computers  

SciTech Connect (OSTI)

Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.

Benioff, P.

1998-07-01T23:59:59.000Z

445

Quantum Darwinism  

SciTech Connect (OSTI)

Quantum Darwinism - proliferation, in the environment, of multiple records of selected states of the system (its information-theoretic progeny) - explains how quantum fragility of individual state can lead to classical robustness of their multitude.

Zurek, Wojciech H [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

446

The Quantum Theory of Fluids  

E-Print Network [OSTI]

The quantum theory of fields is largely based on studying perturbations around non-interacting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is `freer', in the sense that the non-interacting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree- and loop-level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behaviour is radically different to both classical fluids and quantum fields, with interesting physical consequences for fluids in the low temperature regime.

Ben Gripaios; Dave Sutherland

2014-06-24T23:59:59.000Z

447

Quantum mechanical study of solvent effects in a prototype S{sub N}2 reaction in solution: Cl{sup ?} attack on CH{sub 3}Cl  

SciTech Connect (OSTI)

The nucleophilic attack of a chloride ion on methyl chloride is an important prototype S{sub N}2 reaction in organic chemistry that is known to be sensitive to the effects of the surrounding solvent. Herein, we develop a highly accurate Specific Reaction Parameter (SRP) model based on the Austin Model 1 Hamiltonian for chlorine to study the effects of solvation into an aqueous environment on the reaction mechanism. To accomplish this task, we apply high-level quantum mechanical calculations to study the reaction in the gas phase and combined quantum mechanical/molecular mechanical simulations with TIP3P and TIP4P-ew water models and the resulting free energy profiles are compared with those determined from simulations using other fast semi-empirical quantum models. Both gas phase and solution results with the SRP model agree very well with experiment and provide insight into the specific role of solvent on the reaction coordinate. Overall, the newly parameterized SRP Hamiltonian is able to reproduce both the gas phase and solution phase barriers, suggesting it is an accurate and robust model for simulations in the aqueous phase at greatly reduced computational cost relative to comparably accurate ab initio and density functional models.

Kuechler, Erich R. [BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8087 (United States) [BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8087 (United States); Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States); York, Darrin M., E-mail: york@biomaps.rutgers.edu [BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8087 (United States)

2014-02-07T23:59:59.000Z

448

Valuing Stocksg Copyright 2011 Pearson Prentice Hall. All rights reserved.  

E-Print Network [OSTI]

flows are risky, we must discount them at the equity cost of capital. Copyright © 2011 Pearson Prentice of the stock price to estimates of those two factors. Copyright © 2011 Pearson Prentice Hall. All rights to estimate stock value10. Use comparable firm multiples to estimate stock value. Copyright © 2011 Pearson

Schubart, Christoph

449

Physics & Astronomy Open House Schedule UH Manoa Watanabe Hall  

E-Print Network [OSTI]

Physics & Astronomy Open House Schedule UH Manoa Watanabe Hall 22 November 2014 0830 - 1245 *** Physics & Astronomy info. available at www.phys.hawaii.edu *** Welcome & Overview: Prof. Pui Lam in Physical Science 217 at 0830 ** schedules for groups 1 to 10 below for 0900-1100 ** **solar observing

450

401-C Allen Hall Department of Physics and Astronomy  

E-Print Network [OSTI]

401-C Allen Hall Department of Physics and Astronomy 3941 O'Hara Street Pittsburgh, PA 15260 for these problems. A few years ago, a physics and astronomy graduate student, Brian Cherinka, took a course you between a few members of our department of Physics and Astronomy (Michael Wood-Vasey, Arthur Kosowsky

Marai, G. Elisabeta "Liz"

451

Math for Poets and Drummers Rachel Wells Hall  

E-Print Network [OSTI]

Math for Poets and Drummers Rachel Wells Hall Department of Mathematics and Computer Science Saint a meter, is a pattern of stressed and unstressed syllables. English poets use about a dozen different line and "these" in the third line refer to the critics.) 1 #12;But most by Numbers judge a Poet's Song

Hall, Rachel W.

452

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Information U.S. Patent 7,323,683 (issued January 28, 2008) Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;

453

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New. References Sandu, et al. 2010. J. Cell. Biol, 190:1039-52. Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;

454

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New://www.nature.com/tp/journal/v4/n1/abs/tp2013124a.html Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327

de Lange, Titia

455

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10065 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu Alleles of Human Kappa Opioid Receptors and Uses Thereof

456

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New Transfer (212) 327-7095 tsuprapto@rockefeller.edu #12;The Rockefeller University Office of Technology.S. patent application US 2013-0064762-A1 is pending. Tari Suprapto, Ph.D. Assistant Director Technology

457

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu A Novel Disc-Based Apparatus for High-Throughput Sample

458

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu A Novel Regulator Of Extracellular Virulence Genes

459

The Rockefeller University Office of Technology Transfer 502 Founders Hall  

E-Print Network [OSTI]

The Rockefeller University Office of Technology Transfer 502 Founders Hall 1230 York Avenue New York, NY 10021-6399 www.rockefeller.edu/techtransfer Tari Suprapto, Ph.D. Assistant Director Technology Transfer (212) 327-7095 tsuprapto@rockefeller.edu Novel Inhibitors of Thrombotic Clot Formation RU808+ RU

460

FORUMA Hamilton Spectator Town Hall Event SPEAKERS INCLUDE  

E-Print Network [OSTI]

R001990104 OPEN FORUMA Hamilton Spectator Town Hall Event SPEAKERS INCLUDE: STEVE BUIST, Spectator, former chairman of Hamilton-Wentworth region and now president and CEO of the Hamilton Community Foundation. DR. CHRIS MACKIE, Hamilton's associate medical officer of health. MARK CHAMBERLAIN, president

Thompson, Michael

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Dr Rocky K. C. Chang Warden of Lizhi Hall  

E-Print Network [OSTI]

Dr Rocky K. C. Chang Warden of Lizhi Hall Warden Office: Room 968 Intercom: 0968 Email: csrchang in women sports (swimming, field and track, badminton, volleyball, etc). I have confirmed with Ruby on energy saving came as a pleasant surprise. Our achievements are by no means limited to these external

Chang, Rocky Kow-Chuen

462

Hall of Honor 2014: Pursuing Explanations, Discovering Robert Brooks  

E-Print Network [OSTI]

, and in education that inquiry must be guided by practicality, and that technological progress is useless without that inquiry must be guided by practicality, and that technological progress is useless without a dedication, but there is something more about his experience that earns his recognition in the Foundry Management & Technology Hall

Buehrer, R. Michael

463

Sustainable Ecotourism Development Room 222 Newins-Ziegler Hall  

E-Print Network [OSTI]

FOR 4664: Sustainable Ecotourism Development Fall, 2011 Room 222 Newins-Ziegler Hall Tuesday Period Objectives: Students will learn how the emerging concept of ecotourism and outdoor recreation fits, and environmental benefits associated with recreation and ecotourism. The course will take a practical approach

Watson, Craig A.

464

ENGINEERS' DAY 2011 ACTIVITIES 1800 Engineering Hall, 1415 Engineering Drive  

E-Print Network [OSTI]

, Operations Support Exelon Nuclear Warrenville, Illinois Brian J. Rauch Vice President, Engineering John DeereENGINEERS' DAY 2011 ACTIVITIES 1800 Engineering Hall, 1415 Engineering Drive 5:30 SOCIAL HOUR · Distinguished Achievement Awards · Early-Career Achievement Award · College of Engineering faculty and staff

Sheridan, Jennifer

465

Environmental Philosophy and Policy Office: 402 Stratton Hall  

E-Print Network [OSTI]

Syllabus LAIS 421 Environmental Philosophy and Policy Office: 402 Stratton Hall Instructor: Sandy environmental issues, as well as examine the complexity of the issues themselves. Such analyses rest on critical reading, familiarity with fundamental concepts that drive environmental arguments, and the ability

466

Isotope Effect on Adsorbed Quantum Phases: Diffusion of H2 and D2 in Nanoporous Carbon  

SciTech Connect (OSTI)

Quasielastic neutron scattering of H2 and D2 in the same nanoporous carbon at 10–40 K demonstrates extreme quantum sieving, with D2 diffusing up to 76 times faster. D2 also shows liquidlike diffusion while H2 exhibits Chudley-Elliott jump diffusion, evidence of their different relationships with the local lattice of adsorption sites due to quantum effects on intermolecular interactions. The onset of diffusion occurs at 22–25 K for H2 and 10–13 K for D2. At these temperatures, H2 and D2 have identical thermal de Broglie wavelengths that correlate with the dominant pore size.

Contescu, Cristian I.; Zhang, Hongxin; Olsen, Raina J.; Mamontov, Eugene; Morris, James R.; Gallego, Nidia C.

2013-06-01T23:59:59.000Z

467

ESM 201 Ecology of Managed Ecosystems (4.0 units) Fall 2011 Tues, Thurs 8:30 -9:45am; Bren Hall 1414  

E-Print Network [OSTI]

ESM 201 Ecology of Managed Ecosystems (4.0 units) Fall 2011 Tues, Thurs 8:30 - 9:45am; Bren Hall@bren.ucsb.edu) This course covers principles of individual, population, community, and ecosystem ecology, with an emphasis on applications (conservation, resource management, ecological effects of pollution and habitat fragmentation, etc

California at Santa Barbara, University of

468

Quantum-information approach to rotating Bose-Einstein condensates  

SciTech Connect (OSTI)

We investigate the two-dimensional weakly interacting rotating Bose-Einstein condensate by the tools of quantum information theory. The critical exponents of the ground-state fidelity susceptibility and the correlation length of the system are obtained for the sudden change of the ground state when the first vortex is formed. This sudden change can also be indicated by the ground state entanglement. We also find the single-particle entanglement can be an indicator of the angular momentums for some real ground states. The single-particle entanglement of fractional quantum Hall states such as Laughlin state and Pfaffian state is also studied.

Liu Zhao; Guo Hongli; Chen Shu; Fan Heng [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2009-12-15T23:59:59.000Z

469

Anomalous Hall effect in a two-dimensional electron gas  

E-Print Network [OSTI]

transport theory or the diagrammatic approach based on the Kubo- Streda linear-response formalism. The equivalence of these two methods for the two-dimensional Dirac-band graphene system has recently been shown by Sinitsyn et al.,10 who explicitly...

Nunner, Tamara S.; Sinitsyn, N. A.; Borunda, Mario F.; Dugaev, V. K.; Kovalev, A. A.; Abanov, Artem; Timm, Carsten; Jungwirth, T.; Inoue, Jun-ichiro; MacDonald, A. H.; Sinova, Jairo.

2007-01-01T23:59:59.000Z

470

JLab Hall B Radiological Posting Change Effective Nov. 6 | Jefferson...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

RadConpdfformsGenAccRWP.pdf If you have any questions about this notice or the RWP, call the RadCon cell phone at 876-1743. Submitted: Wednesday, November 5, 2014 - 3:25pm...

471

Precise Quantization of Anomalous Hall Effect Near Zero Magnetic Field |  

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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassive Solar Home Design PassivePostdoctoralKanareykin,U DPre-Combustion CO2

472

Cascading and local-field effects in non-linear optics revisited: A quantum-field picture based on exchange of photons  

SciTech Connect (OSTI)

The semi-classical theory of radiation-matter coupling misses local-field effects that may alter the pulse time-ordering and cascading that leads to the generation of new signals. These are then introduced macroscopically by solving Maxwell's equations. This procedure is convenient and intuitive but ad hoc. We show that both effects emerge naturally by including coupling to quantum modes of the radiation field that are initially in the vacuum state to second order. This approach is systematic and suggests a more general class of corrections that only arise in a QED framework. In the semi-classical theory, which only includes classical field modes, the susceptibility of a collection of N non-interacting molecules is additive and scales as N. Second-order coupling to a vacuum mode generates an effective retarded interaction that leads to cascading and local field effects both of which scale as N{sup 2}.

Bennett, Kochise, E-mail: kcbennet@uci.edu; Mukamel, Shaul, E-mail: smukamel@uci.edu [Chemistry Department, University of California, Irvine, California 92697-2025 (United States)] [Chemistry Department, University of California, Irvine, California 92697-2025 (United States)

2014-01-28T23:59:59.000Z

473

Effect of exciton oscillator strength on upconversion photoluminescence in GaAs/AlAs multiple quantum wells  

SciTech Connect (OSTI)

We report upconversion photoluminescence (UCPL) in GaAs/AlAs multiple quantum wells. UCPL from the AlAs barrier is caused by the resonant excitation of the excitons in the GaAs well. When the quantum well has sufficient miniband width, UCPL is hardly observed because of the small exciton oscillator strength. The excitation-energy and excitation-density dependences of UCPL intensity show the exciton resonant profile and a linear increase, respectively. These results demonstrate that the observed UCPL caused by the saturated two-step excitation process requires a large number of excitons.

Kojima, Osamu, E-mail: kojima@phoenix.kobe-u.ac.jp; Okumura, Shouhei; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Akahane, Kouichi [National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795 (Japan)

2014-11-03T23:59:59.000Z

474

Two-dimensional Vortex Behavior in Highly Underdoped YBa2Cu3O6 x Observed by Scanning Hall Probe Microscopy  

SciTech Connect (OSTI)

We report scanning Hall probe microscopy of highly underdoped superconducting YBa{sub 2}Cu{sub 3}O{sub 6+x} with T{sub c} ranging from 5 to 15 K which showed distinct flux bundles with less than one superconducting flux quantum ({Iota}{sub 0}) through the sample surface. The sub-{Iota}{sub 0} features occurred more frequently for lower T{sub c}, were more mobile than conventional vortices, and occurred more readily when the sample was cooled with an in-plane field component. We show that these features are consistent with kinked stacks of pancake vortices.

Guikema, J.W.

2010-02-22T23:59:59.000Z

475

Two-dimensional Vortex Behavior in Highly Underdoped YBa_2Cu_3O_{6+x} Observed byScanning Hall Probe Microscopy  

SciTech Connect (OSTI)

We report scanning Hall probe microscopy of highly underdoped superconducting YBa{sub 2}Cu{sub 3}O{sub 6+z} with T{sub c} ranging from 5 to 15 K which showed distinct flux bundles with less than one superconducting flux quantum ({Phi}{sub 0}) through the sample surface. The sub-{Phi}{sub 0} features occurred more frequently for lower T{sub c}, were more mobile than conventional vortices, and occurred more readily when the sample was cooled with an in-plane field component. We show that these features are consistent with kinked stacks of pancake vortices.

Guikema, J.W.; Bluhm, Hendrik; /Stanford U., Appl. Phys. Dept.; Bonn, D.A.; Liang, Ruixing; Hardy, W.N.; /British Columbia U.; Moler, K.A.; /Stanford U., Appl. Phys. Dept.

2008-04-22T23:59:59.000Z

476

Uncontrolled disorder effects in fabricating photonic quantum simulators on a kagome geometry: A projected-entangled pair state versus exact digonalization analysis  

E-Print Network [OSTI]

We propose a flexible numerical framework for extracting the energy spectra and photon transfer dynamics of a unit kagome cell with disordered cavity-cavity couplings under realistic experimental conditions. A projected-entangled pair state (PEPS) ansatz to the many-photon wavefunction allows to gain a detailed understanding of the effects of undesirable disorder in fabricating well-controlled and scalable photonic quantum simulators. The correlation functions associated with the propagation of two-photon excitations reveal intriguing interference patterns peculiar to the kagome geometry and promise at the same time a highly tunable quantum interferometry device with a signature for the formation of resonant or Fabry-Pe\\'rot-like transmission of photons. Our results justify the use of the proposed PEPS technique for addressing the role of disorder in such quantum simulators in the microwave regime and promises a sophisticated numerical machinery for yet further explorations of the scalability of the resulting kagome arrays. The introduced methodology and the physical results may also pave the way for unraveling exotic phases of correlated light on a kagome geometry.

Amin Hosseinkhani; Bahareh Ghannad Dezfouli; Fatemeh Ghasemipour; Ali T. Rezakhani; Hamed Saberi

2014-06-26T23:59:59.000Z

477

Effect of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content AlGaN quantum well lasers  

E-Print Network [OSTI]

of high Al-content AlGaN quantum well lasers Jing Zhang, Hongping Zhao, and Nelson Tansu Citation: Appl of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content Al characteristics of high Al-content AlGaN quantum wells QWs are analyzed for deep UV lasers. The effect of crystal

Gilchrist, James F.

478

Quantum discord between relatively accelerated observers  

E-Print Network [OSTI]

We calculate the quantum discord between two free modes of a scalar field which start in a maximally entangled state and then undergo a relative, constant acceleration. In a regime where there is no distillable entanglement due to the Unruh effect, we show that there is a finite amount of quantum discord, which is a measure of purely quantum correlations in a state, over and above quantum entanglement. Even in the limit of infinite acceleration of the observer detecting one of the modes, we provide evidence for a non-zero amount of purely quantum correlations, which might be exploited to gain non-trivial quantum advantages.

Animesh Datta

2009-05-20T23:59:59.000Z

479

Hoare Logic for Quantum Programs  

E-Print Network [OSTI]

Hoare logic is a foundation of axiomatic semantics of classical programs and it provides effective proof techniques for reasoning about correctness of classical programs. To offer similar techniques for quantum program verification and to build a logical foundation of programming methodology for quantum computers, we develop a full-fledged Hoare logic for both partial and total correctness of quantum programs. It is proved that this logic is (relatively) complete by exploiting the power of weakest preconditions and weakest liberal preconditions for quantum programs.

Mingsheng Ying

2009-06-25T23:59:59.000Z

480

Polarization preserving quantum nondemolition photodetector  

E-Print Network [OSTI]

A polarization preserving quantum nondemolition photodetector is proposed based on nonlinearities obtainable through quantum coherence effects. An atomic level scheme is devised such that in the presence of strong linearly polarized drive field a coherent weak probe field acquires a phase proportional to the number of photons in the signal mode immaterial of its polarization state. It is also shown that the unavoidable phase-kicks resulting due to the measurement process are insensitive to the polarization state of the incoming signal photon. It is envisioned that such a device would have tremendous applicability in photonic quantum information proposals where quantum information in the polarization qubit is to be protected.

K. T. Kapale

2006-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "quantum hall effect" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Manifestations of topological effects in graphene  

E-Print Network [OSTI]

Graphene is a monoatomic layer of graphite with Carbon atoms arranged in a two dimensional honeycomb lattice configuration. It has been known for more than sixty years that the electronic structure of graphene can be modelled by two-dimensional massless relativistic fermions. This property gives rise to numerous applications, both in applied sciences and in theoretical physics. Electronic circuits made out of graphene could take advantage of its high electron mobility that is witnessed even at room temperature. In the theoretical domain the Dirac-like behavior of graphene can simulate high energy effects, such as the relativistic Klein paradox. Even more surprisingly, topological effects can be encoded in graphene such as the generation of vortices, charge fractionalization and the emergence of anyons. The impact of the topological effects on graphene's electronic properties can be elegantly described by the Atiyah-Singer index theorem. Here we present a pedagogical encounter of this theorem and review its various applications to graphene. A direct consequence of the index theorem is charge fractionalization that is usually known from the fractional quantum Hall effect. The charge fractionalization gives rise to the exciting possibility of realizing graphene based anyons that unlike bosons or fermions exhibit fractional statistics. Besides being of theoretical interest, anyons are a strong candidate for performing error free quantum information processing.

Jiannis K. Pachos

2008-12-05T23:59:59.000Z

482

Effects of n-type doping in InAs/GaAs quantum dot layer on current-voltage characteristic of intermediate band solar cells  

E-Print Network [OSTI]

We investigated the current-voltage characteristic of InAs/GaAs quantum dot intermediate band solar cells (QD IBSCs) with different n-type doping density in the QD layer. The n-type doping evidently increases the open circuit voltage, meanwhile decreases the short circuit current density, and leads to the conversion efficiency approaching that of the control solar cell, that is the major role of n-type doping is to suppress the effects of QDs on the current-voltage characteristic. Our model adopts practical parameters for simulation rather than those from detailed balanced method, so that the results in our simulation are not overestimated.

Gu, Yong-Xian; Ji, Hai-Ming; Xu, Peng-Fei; Yang, Tao

2013-01-01T23:59:59.000Z

483

Electric Time in Quantum Cosmology  

E-Print Network [OSTI]

Effective quantum cosmology is formulated with a realistic global internal time given by the electric vector potential. New possibilities for the quantum behavior of space-time are found, and the high-density regime is shown to be very sensitive to the specific form of state realized.

Stephon Alexander; Martin Bojowald; Antonino Marciano; David Simpson

2012-12-10T23:59:59.000Z

484

Magnetic-field-tuned quantum criticality of the heavy-fermion system YbPtBi  

SciTech Connect (OSTI)

In this paper, we present systematic measurements of the temperature and magnetic field dependencies of the thermodynamic and transport properties of the Yb-based heavy fermion YbPtBi for temperatures down to 0.02 K with magnetic fields up to 140 kOe to address the possible existence of a field-tuned quantum critical point. Measurements of magnetic-field- and temperature-dependent resistivity, specific heat, thermal expansion, Hall effect, and thermoelectric power indicate that the AFM order can be suppressed by an applied magnetic field of Hc?4 kOe. In the H-T phase diagram of YbPtBi, three regimes of its low-temperature states emerge: (I) AFM state, characterized by a spin density wave-like feature, which can be suppressed to T=0 by the relatively small magnetic field of Hc?4 kOe; (II) field-induced anomalous state in which the electrical resistivity follows ??(T)?T1.5 between Hc and ?8 kOe; and (III) Fermi liquid (FL) state in which ??(T)?T2 for H?8 kOe. Regions I and II are separated at T=0 by what appears to be a quantum critical point. Whereas region III appears to be a FL associated with the hybridized 4f states of Yb, region II may be a manifestation of a spin liquid state.

Mun, E. D. [Ames Laboratory; Budko, Serguei L. [Ames Laboratory; Martin, Catalin [Ames Laboratory; Kim, Hyong June [Ames Laboratory; Tanatar, Makariy A. [Ames Laboratory; Park, J.-H. [Florida State University; Murphy, T. [Florida State University; Schmiedeshoff, G. M. [Occidental College; Dilley, N. [Quantum Design; Prozorov, Ruslan [Ames Laboratory; Canfield, Paul C. [Ames Laboratory

2013-02-15T23:59:59.000Z

485

Quantum friction  

E-Print Network [OSTI]

The Brownian motion of a light quantum particle in a heavy classical gas is theoretically described and a new expression for the friction coefficient is obtained for arbitrary temperature. At zero temperature it equals to the de Broglie momentum of the mean free path divided by the mean free path. Alternatively, the corresponding mobility of the quantum particle in the classical gas is equal to the square of the mean free path divided by the Planck constant. The Brownian motion of a quantum particle in a quantum environment is also discussed.

R. Tsekov

2012-03-12T23:59:59.000Z

486

Recent Results of TMD Measurements from Jefferson Lab Hall A  

SciTech Connect (OSTI)

This slide-show presents results on transverse momentum distributions. The presentation covers: target single-spin asymmetry (SSA) (in parity conserving interactions); • Results of JLab Hall A polarized {sup 3}He target TMD measurement; • Semi-­?inclusive deep-inelastic scattering channels (E06-010); • Target single-spin asymmetry A{sub UT}, Collins and Sivers SSA on neutron; • Double-spin asymmetry A{sub LT}, extract TMD g{sub 1T} on neutron; • Inclusive channels SSA (E06-010, E05-015, E07-013) • Target SSA: inclusive {sup 3}He(e,e’) quasi-elastic scattering; • Target SSA: inclusive {sup 3}He(e,e’) deep inelastic-elastic scattering; • New SIDIS experiments planned in Hall-A for JLab-12 GeV.

Jiang, Xiaodong [LANL

2013-10-01T23:59:59.000Z

487

Efficiency limits of quantum well solar cells  

E-Print Network [OSTI]

The quantum well solar cell (QWSC) has been proposed as a flexible means to ensuring current matching for tandem cells. This paper explores the further advantage afforded by the indication that QWSCs operate in the radiative limit because radiative contribution to the dark current is seen to dominate in experimental data at biases corresponding to operation under concentration. The dark currents of QWSCs are analysed in terms of a light and dark current model. The model calculates the spectral response (QE) from field bearing regions and charge neutral layers and from the quantum wells by calculating the confined densities of states and absorption coefficient, and solving transport equations analytically. The total dark current is expressed as the sum of depletion layer and charge neutral radiative and non radiative currents consistent with parameter values extracted from QE fits to data. The depletion layer dark current is a sum of Shockley-Read-Hall non radiative, and radiative contributions. The charge neu...

Connolly, J P; Barnham, K W J; Bushnell, D B; Tibbits, T N D; Roberts, J S

2010-01-01T23:59:59.000Z

488

Gaussian quantum information  

E-Print Network [OSTI]

The science of quantum information has arisen over the last two decades centered on the manipulation of individual quanta of information, known as quantum bits or qubits. Quantum computers, quantum cryptography, and quantum ...

Weedbrook, Christian

489

Gradient instabilities of electromagnetic waves in Hall thruster plasma  

SciTech Connect (OSTI)

This paper presents a linear analysis of gradient plasma instabilities in Hall thrusters. The study obtains and analyzes the dispersion equation of high-frequency electromagnetic waves based on the two-fluid model of a cold plasma. The regions of parameters corresponding to unstable high frequency modes are determined and the dependence of the increments and intrinsic frequencies on plasma parameters is obtained. The obtained results agree with those of previously published studies.

Tomilin, Dmitry [Department of Electrophysics, Keldysh Research Centre, Moscow 125438 (Russian Federation)

2013-04-15T23:59:59.000Z

490

Hall County, Georgia: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

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 on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation,Ohio:Greer County is a countyon State HighwaysHalfwayHalifax ElectricisHall

491

Experimental demonstration of photonic quantum ratchet  

E-Print Network [OSTI]

We created a potential for light with a phase mirror and then experimentally realized a photonic quantum ratchet in an all-optical system, in which ratchet effects can be observed with the naked eye up to more than 22 steps, and quantum resonance can be demonstrated. Our method also provides a new means to simulate quantum particles with classical light, and it can be applied to investigate many other quantum phenomena.

Chi Zhang; Chuan-Feng Li; Guang-Can Guo

2012-09-10T23:59:59.000Z

492

Experimental demonstration of photonic quantum ratchet  

E-Print Network [OSTI]

We create a potential for light with a phase mirror and then experimentally realize a photonic quantum ratchet in an all-optical system. In our experiment, quantum ratchet effects can be observed by the naked eye so that it will be more easy to understand. Our method also provides a new means to simulate quantum particles by classical light, and it can be applied to investigate many other quantum phenomena.

Zhang, Chi; Guo, Guang-Can

2011-01-01T23:59:59.000Z

493

Magnetic quantum ratchet effect in graphene C. Drexler1, S. A. Tarasenko2, P. Olbrich1, J. Karch1, M. Hirmer1, F. Muller1, M. Gmitra1, J. Fabian1,  

E-Print Network [OSTI]

Magnetic quantum ratchet effect in graphene C. Drexler1, S. A. Tarasenko2, P. Olbrich1, J. Karch1-called ratchet effect2 has fascinating ramifica- tions in engineering and natural sciences3­18 . Graphene19 ratchet motion can arise. We report an experimental demonstration of such an electronic ratchet

Ganichev, Sergey

494

Electric quantum walks with individual atoms  

E-Print Network [OSTI]

We report on the experimental realization of electric quantum walks, which mimic the effect of an electric field on a charged particle in a lattice. Starting from a textbook implementation of discrete-time quantum walks, we introduce an extra operation in each step to implement the effect of the field. The recorded dynamics of such a quantum particle exhibits features closely related to Bloch oscillations and interband tunneling. In particular, we explore the regime of strong fields, demonstrating contrasting quantum behaviors: quantum resonances vs. dynamical localization depending on whether the accumulated Bloch phase is a rational or irrational fraction of 2\\pi.

Maximilian Genske; Wolfgang Alt; Andreas Steffen; Albert H. Werner; Reinhard F. Werner; Dieter Meschede; Andrea Alberti

2013-02-08T23:59:59.000Z

495