Unconventional Integer Quantum Hall effect in graphene
V. P. Gusynin; S. G. Sharapov
2005-08-16T23:59:59.000Z
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.
Fractional quantum Hall effect and nonabelian statistics
N. Read; G. Moore
1992-02-03T23:59:59.000Z
It is argued that fractional quantum Hall effect wavefunctions can be interpreted as conformal blocks of two-dimensional conformal field theory. Fractional statistics can be extended to nonabelian statistics and examples can be constructed from conformal field theory. The Pfaffian state is related to the 2D Ising model and possesses fractionally charged excitations which are predicted to obey nonabelian statistics.
The Quantum Hall Effect in Graphene
Paolo Cea
2012-04-24T23:59:59.000Z
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 $\
Integer Quantum Hall Effect in Graphene
Jellal, Ahmed
2015-01-01T23:59:59.000Z
We study the quantum Hall effect in a monolayer graphene by using an approach based on thermodynamical properties. This can be done by considering a system of Dirac particles in an electromagnetic field and taking into account of the edges effect as a pseudo-potential varying continuously along the $x$ direction. At low temperature and in the weak electric field limit, we explicitly determine the thermodynamical potential. With this, we derive the particle numbers in terms of the quantized flux and therefore the Hall conductivity immediately follows.
Integer Quantum Hall Effect in Graphene
Ahmed Jellal
2015-04-24T23:59:59.000Z
We study the quantum Hall effect in a monolayer graphene by using an approach based on thermodynamical properties. This can be done by considering a system of Dirac particles in an electromagnetic field and taking into account of the edges effect as a pseudo-potential varying continuously along the $x$ direction. At low temperature and in the weak electric field limit, we explicitly determine the thermodynamical potential. With this, we derive the particle numbers in terms of the quantized flux and therefore the Hall conductivity immediately follows.
Observation of the Integer Quantum Hall Effect in Record High...
Office of Scientific and Technical Information (OSTI)
the Integer Quantum Hall Effect in Record High-Mobility Uniform Wafer-Scale Epitaxial Graphene Films Grown on the Si-Face of 6H-SiC(0001). Citation Details In-Document Search...
Quantum Anomalous Hall Effect in Hg_1-yMn_yTe Quantum Wells
Liu, Chao-Xing; /Tsinghua U., Beijing /Stanford U., Phys. Dept.; Qi, Xiao-Liang; /Stanford U., Phys. Dept.; Dai, Xi; Fang, Zhong; /Beijing, Inst. Phys.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
2010-03-19T23:59:59.000Z
The quantum Hall effect is usually observed when the two-dimensional electron gas is subjected to an external magnetic field, so that their quantum states form Landau levels. In this work we predict that a new phenomenon, the quantum anomalous Hall effect, can be realized in Hg{sub 1-y}Mn{sub y}Te quantum wells, without the external magnetic field and the associated Landau levels. This effect arises purely from the spin polarization of the Mn atoms, and the quantized Hall conductance is predicted for a range of quantum well thickness and the concentration of the Mn atoms. This effect enables dissipationless charge current in spintronics devices.
Supersymmetry and Unconventional Quantum Hall Effect in Graphene
Motohiko Ezawa
2006-06-03T23:59:59.000Z
We present a unified description of the quantum Hall effect in graphene on the basis of the 8-component Dirac Hamiltonian and the supersymmetric (SUSY) quantum mechanics. It is remarkable that the zero-energy state emerges because the Zeeman splitting is exactly as large as the Landau level separation, as implies that the SUSY is a good symmetry. For nonzero energy states, the up-spin state and the down-spin state form a supermultiplet possessing the spin SU(2) symmetry. We extend the Dirac Hamiltonian to include two indices $j_{\\uparrow}$ and $j_{\\downarrow}$, characterized by the dispersion relation $E(p) \\propto p^{j_{\\uparrow}+j_{\\downarrow}}$ and the Berry phase $\\pi (j_{\\uparrow}-j_{\\downarrow})$. The quantized Hall conductivity is shown to be $\\sigma_{xy}=\\pm (2n+j_{\\uparrow}+j_{\\downarrow}) 2e^{2}/h$.
Intrinsic Spin Hall Effect Induced by Quantum Phase Transition in HgCdTe Quantum Wells
Yang, Wen; Chang, Kai; /Beijing, Inst. Semiconductors; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
2010-03-19T23:59:59.000Z
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.
Yannouleas, Constantine
quantum Hall effect FQHE in two-dimensional 2D semiconductor heterostruc- tures in the presence of a high in finite 2D electronic systems, such as semiconductor quantum dots QDs under high B, ledEdge states in graphene quantum dots: Fractional quantum Hall effect analogies and differences
Scalar spin chirality and quantum hall effect on triangular lattices
Martin, Ivar [Los Alamos National Laboratory; Batista, Cristian D [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
We study the Kondo Lattice and Hubbard models on a triangular lattice for band filling factor 3/4. We show that a simple non-coplanar chiral spin ordering (scalar spin chirality) is naturally realized in both models due to perfect nesting of the fermi surface. The resulting triple-Q magnetic ordering is a natural counterpart of the collinear Neel ordering of the half-filled square lattice Hubbard model. We show that the obtained chiral phase exhibits a spontaneous quantum Hall-effect with {sigma}{sub xy} = e{sup 2}/h.
The Quantum Spin Hall Effect: Theory and Experiment
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
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.
Quantum Hall effect and Landau-level crossing of Dirac fermions in trilayer graphene
Taychatanapat, Thiti
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 ...
The Hausdorff dimension of fractal sets and fractional quantum Hall effect
Wellington da Cruz
2003-05-27T23:59:59.000Z
We consider Farey series of rational numbers in terms of {\\it fractal sets} labeled by the Hausdorff dimension with values defined in the interval 1$ $$ < $$ $$h$$ $$ <$$ $$ 2$ and associated with fractal curves. Our results come from the observation that the fractional quantum Hall effect-FQHE occurs in pairs of {\\it dual topological quantum numbers}, the filling factors. These quantum numbers obey some properties of the Farey series and so we obtain that {\\it the universality classes of the quantum Hall transitions are classified in terms of $h$}. The connection between Number Theory and Physics appears naturally in this context.
Toward theory of quantum Hall effect in graphene
E. V. Gorbar; V. P. Gusynin; V. A. Miransky
2008-11-07T23:59:59.000Z
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.
Coulomb Oscillations and Hall Effect in Quasi-2D Graphite Quantum Dots
McEuen, Paul L.
Coulomb Oscillations and Hall Effect in Quasi-2D Graphite Quantum Dots J. Scott Bunch, Yuval Yaish-temperature electrical transport measurements on gated, quasi-2D graphite quantum dots. In devices with low contact of graphene, a zero band gap semiconductor with two linearly dispersing bands that touch at the corners
Analytic calculations of trial wave functions of the fractional quantum Hall effect on the sphere
Carmem Lucia de Souza Batista; Dingping Li
1996-07-24T23:59:59.000Z
We present a framework for the analytic calculations of the hierarchical wave functions and the composite fermion wave functions in the fractional quantum Hall effect on the sphere by using projective coordinates. Then we calculate the overlaps between these two wave functions at various fillings and small numbers of electrons. We find that the overlaps are all most equal to one. This gives a further evidence that two theories of the fractional quantum Hall effect, the hierarchical theory and the composite fermion theory, are physically equivalent.
Title: Electron-Hole Asymmetric Integer and Fractional Quantum Hall Effect in Bilayer Graphene
Yacoby, Amir
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
Igor A. Shovkovy; Lifang Xia
2015-08-18T23:59:59.000Z
By making use of the generalized Landau-level representation (GLLR) for the quasiparticle propagator, we study the effect of screening on the properties of the quantum Hall states with integer filling factors in graphene. The analysis is performed in the low-energy Dirac model in the improved rainbow approximation, in which the long-range Coulomb interaction is modified by the one-loop static screening effects in the presence of a background magnetic field. By utilizing a rather general ansatz for the propagator, in which all dynamical parameters are running functions of the Landau-level index $n$, we derive a self-consistent set of the Schwinger-Dyson (gap) equations and solve them numerically. The explicit solutions demonstrate that static screening leads to a substantial suppression of the gap parameters in the quantum Hall states with a broken $U(4)$ flavor symmetry. The temperature dependence of the energy gaps is also studied. The corresponding results mimic well the temperature dependence of the activation energies measured in experiment. It is also argued that, in principle, the Landau-level running of the quasiparticle dynamical parameters could be measured via optical studies of the integer quantum Hall states.
arXiv:cond-mat/0411737v223Nov2005 Quantum Spin Hall Effect in Graphene
Cobden, David
reported progress in the preparation of single layer graphene films. These films exhibit the expectedarXiv:cond-mat/0411737v223Nov2005 Quantum Spin Hall Effect in Graphene C.L. Kane and E.J. Mele Dept orbit interactions on the low energy electronic structure of a sin- gle plane of graphene. We find
Quantum Spin Hall Effect in Graphene C. L. Kane and E. J. Mele
Kane, Charles
reported progress in the preparation of single layer graphene films. These films exhibit the expectedQuantum Spin Hall Effect in Graphene C. L. Kane and E. J. Mele Dept. of Physics and Astronomy of a single plane of graphene. We find that in an experimentally accessible low temperature regime
Half integer quantum Hall effect in high mobility single layer epitaxial graphene
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
Fractional quantum Hall effect and insulating phase of Dirac electrons in graphene
Andrei, Eva Y.
semiconductor analogue3 . As a third distinguishing feature of graphene, it has been conjectured of graphene in terms of a two-dimensional (2D) zero-bandgap semiconductor with low energy excitations repreLETTERS Fractional quantum Hall effect and insulating phase of Dirac electrons in graphene Xu Du1
Quantum Spin Hall Eect May 9, 2011
Hall Eect Quantum Spin Hall Eect in Graphene QSHE in quantum well QSHE in strained semiconductor Tim Quantum Spin Hall Eect in Graphene QSHE in quantum well QSHE in strained semiconductor Tim Hsieh Quantum Hsieh Quantum Spin Hall Eect #12;Integer Quantum Hall Eect (IQHE) 2D electron gas at low temperature
Haldane Quantum Hall Effect for Light in a Dynamically Modulated Array of Resonators
Minkov, Momchil
2015-01-01T23:59:59.000Z
Topological insulators have attracted abundant attention for a variety of reasons -- notably, the possibility for lossless energy transport through edge states `protected' against disorder. Topological effects like the Quantum Hall state can be induced through a gauge field, which is however hard to create in practice, especially for charge-neutral particles. One way to induce an effective gauge potential is through a dynamic, time-periodic modulation of the lattice confining such particles. In this way, the Haldane Quantum Hall effect was recently observed in a cold atom system. Here, we show how this same effect can be induced for light confined to a lattice of identical optical resonators, using an on-site modulation of the resonant frequencies. We further demonstrate the existence of one-directional edge states immune to back-scattering losses, and discuss the possibilities for a practical implementation, which would enable slow-light devices of unprecedented quality.
Haldane Quantum Hall Effect for Light in a Dynamically Modulated Array of Resonators
Momchil Minkov; Vincenzo Savona
2015-07-16T23:59:59.000Z
Topological insulators have attracted abundant attention for a variety of reasons -- notably, the possibility for lossless energy transport through edge states `protected' against disorder. Topological effects like the Quantum Hall state can be induced through a gauge field, which is however hard to create in practice, especially for charge-neutral particles. One way to induce an effective gauge potential is through a dynamic, time-periodic modulation of the lattice confining such particles. In this way, the Haldane Quantum Hall effect was recently observed in a cold atom system. Here, we show how this same effect can be induced for light confined to a lattice of identical optical resonators, using an on-site modulation of the resonant frequencies. We further demonstrate the existence of one-directional edge states immune to back-scattering losses, and discuss the possibilities for a practical implementation, which would enable slow-light devices of unprecedented quality.
Shovkovy, Igor A
2015-01-01T23:59:59.000Z
By making use of the generalized Landau-level representation (GLLR) for the quasiparticle propagator, we study the effect of screening on the properties of the quantum Hall states with integer filling factors in graphene. The analysis is performed in the low-energy Dirac model in the improved rainbow approximation, in which the long-range Coulomb interaction is modified by the one-loop static screening effects in the presence of a background magnetic field. By utilizing a rather general ansatz for the propagator, in which all dynamical parameters are running functions of the Landau-level index $n$, we derive a self-consistent set of the Schwinger-Dyson (gap) equations and solve them numerically. The explicit solutions demonstrate that static screening leads to a substantial suppression of the gap parameters in the quantum Hall states with a broken $U(4)$ flavor symmetry. The temperature dependence of the energy gaps is also studied. The corresponding results mimic well the temperature dependence of the activa...
Excitonic gap, phase transition, and quantum Hall effect in graphene
V. P. Gusynin; V. A. Miransky; S. G. Sharapov; I. A. Shovkovy
2006-11-23T23:59:59.000Z
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.
Magnetic Topological Insulator and Quantum Anomalous Hall Effect
Kou, Xufeng
2015-01-01T23:59:59.000Z
magnetic field and a high mobility material with a good 2D confinement [magnetic TI system, the competition between the FM exchange field and the quantum confinement-
Coulomb interaction and magnetic catalysis in the quantum Hall effect in graphene
E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy
2012-02-01T23:59:59.000Z
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.
Field effect in the quantum Hall regime of a high mobility graphene wire
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
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.
Position-Momentum Duality and Fractional Quantum Hall Effect in Chern Insulators
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Claassen, Martin; Lee, Ching-Hua; Thomale, Ronny; Qi, Xiao-Liang; Devereaux, Thomas P
2015-06-11T23:59:59.000Z
We develop a first quantization description of fractional Chern insulators that is the dual of the conventional fractional quantum Hall (FQH) problem, with the roles of position and momentum interchanged. In this picture, FQH states are described by anisotropic FQH liquids forming in momentum-space Landau levels in a fluctuating magnetic field. The fundamental quantum geometry of the problem emerges from the interplay of single-body and interaction metrics, both of which act as momentum-space duals of the geometrical picture of the anisotropic FQH effect. We then present a novel broad class of ideal Chern insulator lattice models that act as dualsmore »of the isotropic FQH effect. The interacting problem is well-captured by Haldane pseudopotentials and affords a detailed microscopic understanding of the interplay of interactions and non-trivial quantum geometry.« less
Position-Momentum Duality and Fractional Quantum Hall Effect in Chern Insulators
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Claassen, Martin [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lee, Ching-Hua [Stanford Univ., CA (United States); Thomale, Ronny [Univ. of Wurzburg (Germany); Qi, Xiao-Liang [Stanford Univ., CA (United States); Devereaux, Thomas P [SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-06-01T23:59:59.000Z
We develop a first quantization description of fractional Chern insulators that is the dual of the conventional fractional quantum Hall (FQH) problem, with the roles of position and momentum interchanged. In this picture, FQH states are described by anisotropic FQH liquids forming in momentum-space Landau levels in a fluctuating magnetic field. The fundamental quantum geometry of the problem emerges from the interplay of single-body and interaction metrics, both of which act as momentum-space duals of the geometrical picture of the anisotropic FQH effect. We then present a novel broad class of ideal Chern insulator lattice models that act as duals of the isotropic FQH effect. The interacting problem is well-captured by Haldane pseudopotentials and affords a detailed microscopic understanding of the interplay of interactions and non-trivial quantum geometry.
Anomalous Quantum Hall Effect of 4D Graphene in Background Fields
L. B Drissi; H. Mhamdi; E. H Saidi
2011-09-05T23:59:59.000Z
Bori\\c{c}i-Creutz (\\emph{BC}) model describing the dynamics of light quarks in lattice \\emph{QCD} has been shown to be intimately linked to the four dimensional extension of 2D graphene refereed below to as four dimensional graphene (\\emph{4D-graphene}). Borrowing ideas from the field theory description of the usual \\emph{2D} graphene, we study in this paper the anomalous quantum Hall effect (AQHE) of the \\emph{BC} fermions in presence of a constant background field strength $\\mathcal{F}_{\\mu \
Wen, Xiao-Gang
The projective construction is a powerful approach to deriving the bulk and edge field theories of non-Abelian fractional quantum Hall (FQH) states and yields an understanding of non-Abelian FQH states in terms of the ...
Igor Romanovsky; Constantine Yannouleas; Uzi Landman
2009-01-15T23:59:59.000Z
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.
Dynamics in the quantum Hall effect and the phase diagram of graphene
E. V. Gorbar; V. P. Gusynin; V. A. Miransky; I. A. Shovkovy
2008-08-28T23:59:59.000Z
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.
Fractional Quantum Hall States in Graphene
Ahmed Jellal; Bellati Malika
2011-04-27T23:59:59.000Z
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 \
Geometric adiabatic transport in quantum Hall states
Semyon Klevtsov; Paul Wiegmann
2015-08-22T23:59:59.000Z
We argue that in addition to the Hall conductance and the nondissipative component of the viscous tensor, there exists a third independent transport coefficient, which is precisely quantized. It takes constant values along quantum Hall plateaus. We show that the new coefficient is the Chern number of a vector bundle over moduli space of surfaces of genus 2 or higher and therefore cannot change continuously along the plateau. As such, it does not transpire on a sphere or a torus. In the linear response theory, this coefficient determines intensive forces exerted on electronic fluid by adiabatic deformations of geometry and represents the effect of the gravitational anomaly. We also present the method of computing the transport coefficients for quantum Hall states.
Engineering of Quantum Hall Effect from Type IIA String Theory on The K3 Surface
Adil Belhaj; Antonio Segui
2010-07-02T23:59:59.000Z
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.
Composite Fermions and the First-Landau-Level Fine Structure of the Fractional Quantum Hall Effect
Haxton, W C
2015-01-01T23:59:59.000Z
We show that an alternative use of operators introduced in 1996 by Ginocchio and Haxton (GH) leads to a simple representation of the wave functions for the fractional quantum Hall effect, as non-interacting quasi-electrons (or composite fermions) fully filling fine-structure subshells within the first Landau level (FLL). In the present GH2 construction each shell corresponds to a distinct quasi-electron, constructed explicitly on both the sphere and the plane as vector products of spinors creating an electron and one unit of magnetic flux, a structure we argue follows from the coordinate scale invariance of the Coulomb potential. The quasi-electrons are eigenstates of angular momentum L and Lz. The hierarchy and conjugate states are the lowest-energy filled-shell configurations of these quasi-electrons, where the energy "counting" is related to Haldane's pseudo-potential. The construction yields a correspondence between the quasi-particle representation of the incompressible FLL state of filling p/(2p +1) and...
Engineering quantum anomalous/valley Hall states in graphene...
Office of Scientific and Technical Information (OSTI)
Engineering quantum anomalousvalley Hall states in graphene via metal-atom adsorption: Anab-initiostudy Prev Next Title: Engineering quantum anomalousvalley Hall states in...
Weston, Ken
Coulomb interactions drive the existence of a correlated many-body state. Bilayer graphene represents distinct two-valued quantum numbers: layer index, electron spin, and the sublattice index of the graphene observation of fractional quantum Hall states in bilayer graphene. By placing bilayer graphene (blue in Fig. 1
Precise adiabatic transport and geometry of quantum Hall states
Klevtsov, Semyon
2015-01-01T23:59:59.000Z
We argue that in addition to the Hall conductance and the non-dissipative component of the viscous tensor there exists a third independent kinetic coefficient which is precise on the quantum Hall plateaus. We show that the new coefficient is the Chern number over moduli space of surfaces of genus two or higher and therefore is precise. As such it does not transpire on a sphere or a torus. In the linear response theory this coefficient determines intensive forces exerted on electronic fluid by adiabatic deformations of geometry and represents the effect of the gravitational anomaly. We also present the method of computing the transport coefficients for quantum Hall states.
Huang, Yi-Zhi
Quantum Hall systems Representation theory of vertex operator algebras Applications The end Quantum;Quantum Hall systems Representation theory of vertex operator algebras Applications The end Outline 1 An approach to a fundamental conjecture #12;Quantum Hall systems Representation theory of vertex operator
Huang, Yi-Zhi
Quantum Hall systems Representation theory of vertex operator algebras Applications The end Quantum Science, CAS #12;Quantum Hall systems Representation theory of vertex operator algebras Applications to a fundamental conjecture #12;Quantum Hall systems Representation theory of vertex operator algebras Applications
Quantum Hall Effect in n-p-n and n-2D Topological Insulator-n Junctions G. M. Gusev,1
Gusev, Guennady
Quantum Hall Effect in n-p-n and n-2D Topological Insulator-n Junctions G. M. Gusev,1 A. D. Levin,1 TI) with locally controlled density allowing n-p-n and n-2D TI-n junctions. The resistance reveals quantization in the graphene p-n [1] or n-p-n [2,3] junctions, which has been attributed to chiral edge states
Infrared Hall Effect in cuprates*
Fominov, Yakov
Diagram #12;Fermi surfaces H. KONTANI, K. KANKI, AND K. UEDA PRB 59 (1999). #12;IR Hall EffectB i m c = - 2 2 4 ( ) p H xy i = - =1000 cm-1 Schmadel, et al, PRB (2007) #12;Opt. Bi(2212): Far IR Hall H H i = - 84 cm-1 Schmadel, et al, PRB (2007) H ~ 0.3 cm-1/T H ~ aT1.65 #12
Viscosity of Quantum Hall Fluids J. E. Avron
Viscosity of Quantum Hall Fluids J. E. Avron Department of Physics, Technion, 32000 Haifa, Israel R April 25, 1997 Abstract The viscosity of quantum fluids with an energy gap at zero temperature is non of the parameter space). For a quantum Hall fluid on two dimensional tori this viscosity is computed. In this case
Kane, Charles
is varied, the degree of back- scattering between the two counterpropagating modes can be varied. For strong depletion under the gate, all backscattering can be effectively eliminated, and the source to drain con- ductance vanishes. In the opposite limit, the gate potential can be turned off, and the two-terminal source-to-drain
Y-shape spin-separator for two-dimensional group-IV nanoribbons based on quantum spin hall effect
Gupta, Gaurav, E-mail: a0089293@nus.edu.sg; Abdul Jalil, Mansoor Bin; Liang, Gengchiau, E-mail: elelg@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Lin, Hsin [Graphene Research Centre and Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Bansil, Arun [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Huang, Cheng-Yi; Tsai, Wei-Feng [Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China)
2014-01-20T23:59:59.000Z
An efficient spin-separator that operates in quantum spin hall phase has been investigated for two-dimensional group-IV materials. A three-terminal Y-shaped device has been simulated via non-equilibrium Green Function to demonstrate the separation of unpolarized current at source terminal into spin-polarized current of opposite polarity at the two drain terminals. Device controls, i.e., tunable buckling and perpendicular magnetic field have been modeled comprehensively to evaluate the device feasibility and performance. It is shown that these controls can preferentially steer current between the two drains to create a differential charge current with complementary spin polarization, thus enabling a convenient regulation of output signal.
Contactless measurement of alternating current conductance in quantum Hall structures
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
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.
Constantine Yannouleas; Igor Romanovsky; Uzi Landman
2010-09-13T23:59:59.000Z
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.
Topological order in the fractional quantum Hall states
Barkeshli, Maissam
2010-01-01T23:59:59.000Z
This thesis is focused on the theoretical characterization of topological order in non-Abelian fractional quantum Hall (FQH) states. The first part of the thesis is concerned with the ideal wave function approach to FQH ...
Comments on Hall transport from effective actions
Felix M. Haehl; Mukund Rangamani
2015-01-18T23:59:59.000Z
We consider parity-odd transport in 2+1 dimensional charged fluids restricting attention to the class of non-dissipative fluids. We show that there is a two parameter family of such non-dissipative fluids which can be derived from an effective action, in contradistinction with a four parameter family that can be derived from an entropy current analysis. The effective action approach allows us to extract the adiabatic transport data, in particular the Hall viscosity and Hall conductivity amongst others, in terms of the thermodynamic functions that enter as 'coupling constants'. Curiously, we find that Hall viscosity is forced to vanish, whilst the Hall conductivity is generically a non-vanishing function of thermodynamic data determined in terms of the hydrodynamic couplings.
Gapless layered three-dimensional fractional quantum Hall states Michael Levin1
2D , anisotropic three-dimensional 3D electron systems--such as multilayer systems in a perpen of experiments on 3D semiconductor multilayers have explored the behavior of stacked integer quantum Hall states effect in graphene,2023 and future pros- pects for graphene multilayers, provides further impetus
The fluctuation induced Hall effect
Shen, W.; Prager, S.C.
1993-02-01T23:59:59.000Z
The fluctuation induced Hall term, [le][approximately][ovr J] [times] [approximately][ovr B][ge], has been measured in the MST reversed field pinch. The term is of interest as a possible source of current self-generation (dynamo). It is found to be non-negligible, but small in that it can account for less than 25% of the dynamo driven current.
The fluctuation induced Hall effect
Shen, W.; Prager, S.C.
1993-02-01T23:59:59.000Z
The fluctuation induced Hall term, {le}{approximately}{ovr J} {times} {approximately}{ovr B}{ge}, has been measured in the MST reversed field pinch. The term is of interest as a possible source of current self-generation (dynamo). It is found to be non-negligible, but small in that it can account for less than 25% of the dynamo driven current.
Magnetic Catalysis and Quantum Hall Ferromagnetism in Weakly Coupled Graphene
Gordon W. Semenoff; Fei Zhou
2011-04-25T23:59:59.000Z
We study the realization in a model of graphene of the phenomenon whereby the tendency of gauge-field mediated interactions to break chiral symmetry spontaneously is greatly enhanced in an external magnetic field. We prove that, in the weak coupling limit, and where the electron-electron interaction satisfies certain mild conditions, the ground state of charge neutral graphene in an external magnetic field is a quantum Hall ferromagnet which spontaneously breaks the emergent U(4) symmetry to U(2)XU(2). We argue that, due to a residual CP symmetry, the quantum Hall ferromagnet order parameter is given exactly by the leading order in perturbation theory. On the other hand, the chiral condensate which is the order parameter for chiral symmetry breaking generically obtains contributions at all orders. We compute the leading correction to the chiral condensate. We argue that the ensuing fermion spectrum resembles that of massive fermions with a vanishing U(4)-valued chemical potential. We discuss the realization of parity and charge conjugation symmetries and argue that, in the context of our model, the charge neutral quantum Hall state in graphene is a bulk insulator, with vanishing longitudinal conductivity due to a charge gap and Hall conductivity vanishing due to a residual discrete particle-hole symmetry.
Hall effect in incompressible magnetic reconnection
Dasso, Sergio
. GoÂ´mez Instituto de AstronomiÂ´a y FiÂ´sica del Espacio (IAFE), Departamento de FiÂ´sica, Facultad de region. Citation: Morales, L. F., S. Dasso, and D. O. GoÂ´mez (2005), Hall effect in incompressible
Geometric Spin Hall Effect of Light
Andrea Aiello; Christoph Marquardt; Gerd Leuchs
2009-02-26T23:59:59.000Z
We describe a novel phenomenon occurring when a polarized Gaussian beam of light is observed in a Cartesian reference frame whose axes are not parallel to the direction of propagation of the beam. Such phenomenon amounts to an intriguing spin-dependent shift of the position of the center of the beam, with manners akin to the spin Hall effect of light. We demonstrate that this effect is unavoidable when the light beam possesses a nonzero transverse angular momentum.
Crystalline phases of graphene quantum Hall polariton fluids
Francesco M. D. Pellegrino; Vittorio Giovannetti; Allan H. MacDonald; Marco Polini
2015-05-26T23:59:59.000Z
There is growing experimental interest in coupling cavity photons to the cyclotron resonance excitations of electron liquids in high-mobility semiconductor quantum wells or graphene sheets. These media offer unique platforms to carry out fundamental studies of exciton-polariton condensation and cavity quantum electrodynamics in a regime in which electron-electron (e-e) interactions are expected to play a pivotal role. Focusing on graphene, we present a theoretical study of the impact of e-e interactions on a quantum Hall polariton fluid (QHPF), i.e. a fluid of magneto-excitons resonantly coupled to cavity photons. We show that e-e interactions are responsible for an instability of graphene integer QHPFs towards a crystalline phase. We demonstrate that this phase can be detected by measuring the collective excitation spectra, which soften at a characteristic wave vector of the order of the inverse magnetic length.
Temperature dependence of conductance fluctuations in quantum Hall multilayers H. A. Walling,1
Xu, Jing
)]. This surface phase dominates vertical transport at low temperatures that freeze out parallel bulk transport.2 fluctuations in low-temperature, vertical transport through quantum Hall multilayers. The mesas studied dependence of reproduc- ible conductance fluctuations in quantum Hall multilayers. The vertical transport
Higgs Mechanism and Anomalous Hall Effect in Three-Dimensional Topological Superconductors
Nogueira, Flavio S; Eremin, Ilya
2015-01-01T23:59:59.000Z
We demonstrate that the Higgs mechanism in three-dimensional topological superconductors exhibits unique features with experimentally observable consequences. The Higgs model we discuss has two superconducting components and an axion-like magnetoelectric term with the phase difference of the superconducting order parameters playing the role of the axion field. Due to this additional term, quantum electromagnetic and phase fluctuations lead to a robust topologically non-trivial state that cannot be continuously deformed into a topologically non-trivial one. In the low frequency London regime an anomalous Hall effect is induced in the presence of an applied electric field parallel to the surface. This anomalous Hall current is induced by a Lorentz-like force arising from the axion term, and it involves the relative superfluid velocity of the superconducting components. The anomalous Hall current has a negative sign, a situation reminiscent, but quite distinct in physical origin, of the anomalous Hall effect obs...
Hall effect at a tunable metal-insulator transition
Teizer, Winfried; Hellman, F.; Dynes, RC.
2003-01-01T23:59:59.000Z
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...
Hall effect at a tunable metal-insulator transition
Teizer, Winfried; Hellman, F.; Dynes, RC.
2003-01-01T23:59:59.000Z
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...
Pulsed field UCu5 Hall effect and magnetization (I)
Mcdonald, Ross D [Los Alamos National Laboratory; Ayala - Valenzuela, Oscar E [Los Alamos National Laboratory; Ben, Ueland G [Los Alamos National Laboratory; Corneliu, Miclea [Los Alamos National Laboratory; Movshovich, R [Los Alamos National Laboratory; Tompson, J. D. [Los Alamos National Laboratory; Bauer, E [Los Alamos National Laboratory; Batista, C. D. [Los Alamos National Laboratory; Martin, I [Los Alamos National Laboratory
2011-01-14T23:59:59.000Z
Prior studies of UCu{sub 5} identified the material as undergoing antiferromagnetic ordering at a temperature of 15 K with a subsequent reduction of the electronic density of states, evident as sharp upturn in resistance, at 1.4 K. High field magnetization measurements indicate a complex temperature-field phase diagram comprising of numerous phases below 15 K up and up to 60 T, with NMR and neutron measurements identifying both simple anitferromagnetic and 4Q-magnetic structures at low fields. The purpose of our investigations is to identify the possibly strong coupling between the itinerant electrons and the local spin structures, such as quantum amplification of the Hall effect due to (field induced) non-colinear spin textures. Comparison with prior literature indicates the sensitivity of the phase stability of the different spin textures to composition and sample preparation. However, the 'simplified' phase diagram of this composition offers the possibility of exploring, anomalous Hall properties arising from a field induced non-colinear spin texture over a wide range of temperatures and magnetic fields.
Electrically tunable quantum spin Hall state in topological crystalline insulator thin films
Liu, Junwei
Based on electronic structure calculations and theoretical analysis, we predict the (111) thin films of the SnTe class of three-dimensional (3D) topological crystalline insulators (TCIs) realize the quantum spin Hall phase ...
Snizhko, K.
In a recent experimental paper [Bid et al., Nature 466, 585 (2010)] a qualitative confirmation of the existence of upstream neutral modes at the ? = 2/3 quantum Hall edge was reported. Using the chiral Luttinger liquid ...
Unconventional Quantum Hall Effect and Tunable Spin Hall Effect...
Office of Scientific and Technical Information (OSTI)
Date: 2013-02-01 OSTI Identifier: 1102031 Type: Publisher's Accepted Manuscript Journal Name: Physical Review Letters Additional Journal Information: Journal Volume: 110;...
Experimental Observation of the Inverse Spin Hall Effect at Room Temperature
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
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.
Topological solitons in the noncommutative plane and quantum Hall Skyrmions
Ezawa, Z.F. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan); Tsitsishvili, G. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan); Department of Theoretical Physics, A. Razmadze Mathematical Institute, Tbilisi, 380093 (Georgia)
2005-10-15T23:59:59.000Z
We analyze topological solitons in the noncommutative plane by taking a concrete instance of the quantum Hall system with the SU(N) symmetry, where a soliton is identified with a Skyrmion. It is shown that a topological soliton induces an excitation of the electron number density from the ground-state value around it. When a judicious choice of the topological charge density J{sub 0}(x) is made, it acquires a physical reality as the electron density excitation {delta}{rho}{sup cl}(x) around a topological soliton, {delta}{rho}{sup cl}(x)=-J{sub 0}(x). Hence a noncommutative soliton carries necessarily the electric charge proportional to its topological charge. A field-theoretical state is constructed for a soliton state irrespectively of the Hamiltonian. In general, it involves an infinitely many parameters. They are fixed by minimizing its energy once the Hamiltonian is chosen. We study explicitly the cases where the system is governed by the hard-core interaction and by the noncommutative CP{sup N-1} model, where all these parameters are determined analytically and the soliton excitation energy is obtained.
Geller, Michael R.
N = z1 z2 Â¯ zN 2 of charge-1 fermion fields :ei 2 : M, where is a u 1 boson15 and M a neutral Majorana anyon braiding for fault-tolerant quantum computation.20 Unfortunately, the braiding matrices gener
Optical detection of spin Hall effect in metals
Erve, O. M. J. van ‘t, E-mail: Olaf.Vanterve@nrl.navy.mil; Hanbicki, A. T.; McCreary, K. M.; Li, C. H.; Jonker, B. T. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)
2014-04-28T23:59:59.000Z
Optical techniques have been widely used to probe the spin Hall effect in semiconductors. In metals, however, only electrical methods such as nonlocal spin valve transport, ferromagnetic resonance, or spin torque transfer experiments have been successful. These methods require complex processing techniques and measuring setups. We show here that the spin Hall effect can be observed in non-magnetic metals such as Pt and ?-W, using a standard bench top magneto-optical Kerr system with very little sample preparation. Applying a square wave current and using Fourier analysis significantly improve our detection level. One can readily determine the angular dependence of the induced polarization on the bias current direction (very difficult to do with voltage detection), the orientation of the spin Hall induced polarization, and the sign of the spin Hall angle. This optical approach is free from the complications of various resistive effects, which can compromise voltage measurements. This opens up the study of spin Hall effect in metals to a variety of spin dynamic and spatial imaging experiments.
Color Glass Condensates in dense quark matter and quantum Hall states of gluons
Aiichi Iwazaki
2006-04-26T23:59:59.000Z
We apply the effective theory of color glass condensate to the analysis of gluon states in dense quark matter, in which the saturation region of gluons is also present. We find that in the region two point function of gluons shows algebraic long range order. The order is completely the same as the one gluons show in the dense quark matter, which form quantum Hall states. The order leads to the vanishing of massless gluon pole. We also find that the saturation region of gluons extends from small $x$ to even large $x\\lesssim 1$ in much dense quark matter. We point out a universality that the color glass condensate is a property of hadrons at high energy and of quark matter at high baryon density.
Electric control of the spin Hall effect by intervalley transitions
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
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...
"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"
Escolano, Francisco
"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
"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"
Escolano, Francisco
"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
"Impact of heavy adatom segregation on the quantum spin Hall phase in graphene"
Escolano, Francisco
"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
Lo, Shun-Tsung; Hsu, Chang-Shun [Graduate Institute of Applied Physics, National Taiwan University, Taipei 10617, Taiwan (China); Lin, Y. M.; Lin, S.-D.; Lee, C. P. [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Ho, Sheng-Han; Chuang, Chiashain; Wang, Yi-Ting [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Liang, C.-T. [Graduate Institute of Applied Physics, National Taiwan University, Taipei 10617, Taiwan (China); Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China)
2014-07-07T23:59:59.000Z
We study interference and interactions in an InAs/InAsSb two-dimensional electron system. In such a system, spin-orbit interactions are shown to be strong, which result in weak antilocalization (WAL) and thereby positive magnetoresistance around zero magnetic field. After suppressing WAL by the magnetic field, we demonstrate that classical positive magnetoresistance due to spin-orbit coupling plays a role. With further increasing the magnetic field, the system undergoes a direct insulator-quantum Hall transition. By analyzing the magnetotransport behavior in different field regions, we show that both electron-electron interactions and spin-related effects are essential in understanding the observed direct transition.
Niu, Qian
numbers: 72.10.Bg, 72.20.Dp, 73.63.Hs The generation of an electric current in the transverse direction, other variants, such as the thermal Hall effect[3], can manifest when the longitudi- nal electric field of an electric field is known as a Hall effect. The transverse force is usually provided by the Lorentz force
Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon
Bernevig, B.Andrei; Hughes, Taylor L.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.
2010-01-15T23:59:59.000Z
The spin Hall effect depends crucially on the intrinsic spin-orbit coupling of the energy band. Because of the smaller spin-orbit coupling in silicon, the spin Hall effect is expected to be much reduced. We show that the electric field in p-doped silicon can induce a dissipationless orbital current in a fashion reminiscent of the spin Hall effect. The vertex correction due to impurity scattering vanishes and the effect is therefore robust against disorder. The orbital Hall effect can lead to the accumulation of local orbital momentum at the edge of the sample, and can be detected by the Kerr effect.
Anomalous Hall effect in a two-dimensional electron gas
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
Anomalous Hall effect in a two-dimensional electron gas Tamara S. Nunner,1 N. A. Sinitsyn,2,3 Mario F. Borunda,2 V. K. Dugaev,4 A. A. Kovalev,2 Ar. Abanov,2 Carsten Timm,5 T. Jungwirth,6,7 Jun-ichiro Inoue,8 A. H. MacDonald,9 and Jairo Sinova2...,6 1Institut f?r Theoretische Physik, Freie Universit?t Berlin, Arnimallee 14, 14195 Berlin, Germany 2Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA 3CNLS/CCS-3, Los Alamos National Laboratory, Los Alamos, New...
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
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.
Observation of Chiral Heat Transport in the Quantum Hall Regime G. Granger,1
Eisenstein, Jim
91125, USA 2 Sandia National Laboratories, Albuquerque, New Mexico 87185, USA (Received 17 October 2008 are based on the thermoelectric effect. In the ¼ 1 integer quantized Hall state, a thermoelectric signal, the thermoelectric signal is reduced, showing that the electrons cool as they propagate along the edge. DOI: 10
Krypton charge exchange cross sections for Hall effect thruster models
Hause, Michael L. [Institute for Scientific Research, Boston College, Chestnut Hill, Massachusetts 02159 (United States); Prince, Benjamin D.; Bemish, Raymond J. [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117 (United States)
2013-04-28T23:59:59.000Z
Following discharge from a Hall effect thruster, charge exchange occurs between ions and un-ionized propellant atoms. The low-energy cations produced can disturb operation of onboard instrumentation or the thruster itself. Charge-exchange cross sections for both singly and doubly charged propellant atoms are required to model these interactions. While xenon is the most common propellant currently used in Hall effect thrusters, other propellants are being considered, in particular, krypton. We present here guided-ion beam measurements and comparisons to semiclassical calculations for Kr{sup +} + Kr and Kr{sup 2+} + Kr cross sections. The measurements of symmetric Kr{sup +} + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr{sup 2+} + Kr reaction, we present cross section measurements for center-of-mass energies between 1 eV and 300 eV, which spans energies not previously examined experimentally. These cross section measurements compare well with a simple one-electron transfer model. Finally, cross sections for the asymmetric Kr{sup 2+} + Kr {yields} Kr{sup +} + Kr{sup +} reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 A{sup 2} with an exception near 70-80 eV.
Zhou, Miao [Univ. of Utah, Salt Lake City, UT (United States); Ming, Wenmei [Univ. of Utah, Salt Lake City, UT (United States); Liu, Zheng [Univ. of Utah, Salt Lake City, UT (United States); Wang, Zhengfei [Univ. of Utah, Salt Lake City, UT (United States); Yao, Yugui [Beijing Institute of Technology, Beijing (China); Liu, Feng [Univ. of Utah, Salt Lake City, UT (United States); Collaborative Innovation Center of Quantum Matter, Beijing (China)
2014-11-19T23:59:59.000Z
For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ?0.5 eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhou, Miao; Ming, Wenmei; Liu, Zheng; Wang, Zhengfei; Yao, Yugui; Liu, Feng
2014-11-19T23:59:59.000Z
For potential applications in spintronics and quantum computing, it is desirable to place a quantum spin Hall insulator [i.e., a 2D topological insulator (TI)] on a substrate while maintaining a large energy gap. Here, we demonstrate a unique approach to create the large-gap 2D TI state on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show that when heavy elements with strong spin orbit coupling (SOC) such as Bi and Pb atoms are deposited on a patterned H-Si(111) surface into a hexagonal lattice, they exhibit a 2D TI state with a large energy gap of ?0.5more »eV. The TI state arises from an intriguing substrate orbital filtering effect that selects a suitable orbital composition around the Fermi level, so that the system can be matched onto a four-band effective model Hamiltonian. Furthermore, it is found that within this model, the SOC gap does not increase monotonically with the increasing strength of SOC. These interesting results may shed new light in future design and fabrication of large-gap topological quantum states.« less
Towards Managing Variability in the Safety Design of an Automotive Hall Effect Sensor
Paris-Sud XI, Université de
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
Fully-kinetic PIC simulations for Hall-effect thrusters
Fox, Justin M., 1981-
2007-01-01T23:59:59.000Z
In recent years, many groups have numerically modeled the near-anode region of a Hall thruster in attempts to better understand the associated physics of thruster operation. Originally, simulations assumed a continuum ...
Investigation of magnetic proximity effect in Ta/YIG bilayer Hall bar structure
Yang, Yumeng [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583 (Singapore); Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Wu, Baolei; Wu, Yihong, E-mail: elewuyh@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583 (Singapore); Yao, Kui; Shannigrahi, Santiranjan [Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Zong, Baoyu [Temasek Laboratories, National University of Singapore, T-Lab Building, 5A Engineering Drive 1, 09-02, Singapore 117411 (Singapore)
2014-05-07T23:59:59.000Z
In this work, the investigation of magnetic proximity effect was extended to Ta which has been reported to have a negative spin Hall angle. Magnetoresistance (MR) and Hall measurements for in-plane and out-of-plane applied magnetic field sweeps were carried out at room temperature. The size of the MR ratio observed (?10{sup ?5}) and its magnetization direction dependence are similar to that reported in Pt/yttrium iron garnet, both of which can be explained by the spin Hall magnetoresistance theory. Additionally, a flip of magnetoresistance polarity is observed at 4?K in the temperature dependent measurements, which can be explained by the magnetic proximity effect induced anisotropic magnetoresistance at low temperature. Our findings suggest that both magnetic proximity effect and spin Hall magnetoresistance have contribution to the recently observed unconventional magnetoresistance effect.
Multi-DOF precision positioning methodology using two-axis Hall-effect sensors
Kawato, Yusuke
2006-08-16T23:59:59.000Z
A novel sensing methodology using two-axis Hall-effect sensors is proposed, where the absolute positioning of a device atop any magnet matrix is possible. This methodology has the capability of micrometer-order positioning resolution as well...
Gauge Potential Formulations of the Spin Hall Effect in Graphene
O. F. Dayi; E. Yunt
2011-05-27T23:59:59.000Z
Two different gauge potential methods are engaged to calculate explicitly the spin Hall conductivity in graphene. The graphene Hamiltonian with spin-orbit interaction is expressed in terms of kinematic momenta by introducing a gauge potential. A formulation of the spin Hall conductivity is established by requiring that the time evolution of this kinematic momentum vector vanishes. We then calculated the conductivity employing the Berry gauge fields. We show that both of the gauge fields can be deduced from the pure gauge field arising from the Foldy-Wouthuysen transformations.
Electroweak Hall Effect of Neutrino and Coronal Heating
Kenzo Ishikawa; Yutaka Tobita
2015-03-25T23:59:59.000Z
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.
Genomic instability and bystander effects induced by high-LET radiation Eric J Hall*,1
of the radiobiological effects of high- linear energy transfer (LET) radiation is essential for radiation protectionGenomic instability and bystander effects induced by high-LET radiation Eric J Hall*,1 and Tom K, it has always been accepted that the deleterious effects of ionizing radiation, such as mutation
Disorder effects in the anomalous Hall effect induced by Berry curvature RID B-5617-2009
Sinitsyn, NA; Niu, Q.; Sinova, Jairo; Nomura, K.
2005-01-01T23:59:59.000Z
Disorder effects in the anomalous Hall effect induced by Berry curvature N. A. Sinitsyn,1 Qian Niu,1 Jairo Sinova,2 and Kentaro Nomura1 1Department of Physics, University of Texas at Austin, Austin Texas 78712-1081, USA 2Department of Physics..., Texas A&M University, College Station, Texas 77843-4242, USA #1;Received 25 February 2005; published 20 July 2005#2; We describe the charge transport in ferromagnets with spin-orbit coupled Bloch bands by combining the wave-packet evolution equations...
The Effect of Magnetic Field on the Performance of Low-Power Cylindrical Hall Thrusters
The Effect of Magnetic Field on the Performance of Low-Power Cylindrical Hall Thrusters IEPC-2005-099 Presented at the 29th International Electric Propulsion Conference, Princeton University, October 31 for scaling down. The effect of the magnetic field on the discharge characteristics and efficiency of the low
Unconventional Quantum Hall Effect and Tunable Spin Hall Effect in Dirac
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect1.08]Te[subscriptM-PACEResponses tocorrection.Theory (Conference)properties(Technical
Effective anomalous Hall coefficient in an ultrathin Co layer sandwiched by Pt layers
Zhang, Peng; Wu, Di; Jiang, Zhengsheng; Sang, Hai, E-mail: weiwei.lin@u-psud.fr, E-mail: haisang@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Lin, Weiwei, E-mail: weiwei.lin@u-psud.fr, E-mail: haisang@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Institut d'Electronique Fondamentale, Université Paris-Sud, Orsay 91405 (France)
2014-02-14T23:59:59.000Z
Anomalous Hall effect in Co/Pt multilayer is important to study the effect of interface with strong spin-orbit coupling. However, the shunting effect of the layers in such system and the circuit in the plane perpendicular to the injected current were overlooked in most works and thus, anomalous Hall coefficient in Co/Pt multilayer has not been determined accurately. Considering the shunting effect and the equivalent circuit, we show that the effective anomalous Hall coefficient of a 0.5?nm thick Co layer sandwiched by Pt layers R{sub S} is 0.29?±?0.01????cm/T at the zero temperature limit and increases to about 0.73????cm/T at the temperature of 300?K. R{sub S} is one order larger than that in bulk Co film, indicating the large contribution of the Co/Pt interface. R{sub S} increases with the resistivity of Co as well as a resistivity independent contribution of ?0.23?±?0.01????cm/T. The equivalent anomalous Hall current in the Co layer has a maximum of 1.1% of the injected transverse current in the Co layer around the temperature of 80?K.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kozuka, Y.; Tsukazaki, A.; Maryenko, D.; Falson, J.; Bell, C.; Kim, M.; Hikita, Y.; Hwang, H. Y.; Kawasaki, M.
2012-02-01T23:59:59.000Z
We investigate the spin susceptibility (g*m*) of dilute two-dimensional (2D) electrons confined at the MgxZn1-xO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of g*m*, dominated by the increase in the Landé g-factor. The g-factor enhancement leads to a ferromagnetic instability of the electron gas as evidenced by sharp resistance spikes. At high magnetic field, the large g*m* leads to full spin polarization, where we found sudden increase in resistance around the filling factors of half-integer, accompanied by complete disappearance of fractional quantum Hall (QH) states. Along with its large effective mass and the high electron mobility, our result indicates thatmore »the ZnO 2D system is ideal for investigating the effect of electron correlations in the QH regime.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kozuka, Y.; Tsukazaki, A.; Maryenko, D.; Falson, J.; Bell, C.; Kim, M.; Hikita, Y.; Hwang, H. Y.; Kawasaki, M.
2012-02-01T23:59:59.000Z
We investigate the spin susceptibility (g*m*) of dilute two-dimensional (2D) electrons confined at the MgxZn1-xO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of g*m*, dominated by the increase in the Landé g-factor. The g-factor enhancement leads to a ferromagnetic instability of the electron gas as evidenced by sharp resistance spikes. At high magnetic field, the large g*m* leads to full spin polarization, where we found sudden increase in resistance around the filling factors of half-integer, accompanied by complete disappearance of fractional quantum Hall (QH) states. Along with its large effective mass and the high electron mobility, our result indicates that the ZnO 2D system is ideal for investigating the effect of electron correlations in the QH regime.
Effects of ionization distribution on plasma beam focusing characteristics in Hall thrusters
Ning Zhongxi; Liu Hui; Yu Daren [Plasma Propulsion Laboratory, Harbin Institute of Technology, Harbin 150001 (China); Zhou Zhongxiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China)
2011-11-28T23:59:59.000Z
The relationship between ionization distribution and divergence of plasma beam in a Hall thruster is investigated using spectrum and probe methods. Experimental results indicate that the shift of ionization region towards the exit of channel causes the reduction of accelerating field and the enhancement of electron thermal pressure effect, which result in further deviation of equipotential lines to magnetic field lines and further increase in divergence of plasma beam. It is, therefore, suggested that to put the ionization region deep inside the channel and separate it from the acceleration region at the design, and development stage is helpful to improve the plasma beam focusing characteristics of a Hall thruster.
Experimental evidences of a large extrinsic spin Hall effect in AuW alloy
Laczkowski, P.; Rojas-Sánchez, J.-C. [Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 91767 Palaiseau (France); INAC/SP2M, CEA-Université Joseph Fourier, F-38054 Grenoble (France); Savero-Torres, W.; Notin, L.; Beigné, C.; Marty, A.; Attané, J.-P.; Vila, L. [INAC/SP2M, CEA-Université Joseph Fourier, F-38054 Grenoble (France); Jaffrès, H.; Reyren, N.; Deranlot, C.; George, J.-M.; Fert, A. [Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 91767 Palaiseau (France)
2014-04-07T23:59:59.000Z
We report an experimental study of a gold-tungsten alloy (7 at. % W concentration in Au host) displaying remarkable properties for spintronics applications using both magneto-transport in lateral spin valve devices and spin-pumping with inverse spin Hall effect experiments. A very large spin Hall angle of about 10% is consistently found using both techniques with the reliable spin diffusion length of 2?nm estimated by the spin sink experiments in the lateral spin valves. With its chemical stability, high resistivity, and small induced damping, this AuW alloy may find applications in the nearest future.
Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster
circuit leaves very little room for magnetic pole pieces and heat shields. Propulsion Research EngineerDischarge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster IEPC-2009-122 Presented at the 31st International Electric Propulsion Conference, Ann Arbor, MI September 20-24, 2009 K
Manifestation of the spin Hall effect through charge-transport in the mesoscopic regime
Hankiewicz, EM; Molenkamp, LW; Jungwirth, T.; Sinova, Jairo.
2004-01-01T23:59:59.000Z
We study theoretically the manifestation of the spin Hall effect in a two-dimensional electronic system with Rashba spin-orbit coupling via dc-transport measurements in realistic mesoscopic H-shape structures. The Landauer-Buttiker formalism is used...
TL173L, TL173C LINEAR HALL-EFFECT SENSORS
Ida, Nathan
Sheet Page 1 of 3http://www.ionpool.net/arcade/irobot/tl173l.html #12;Recommended operating conditions Linear Hall-Effect Sensor Data Sheet Page 2 of 3http://www.ionpool.net/arcade/irobot/tl173l.html #12;last://www.ionpool.net/arcade/irobot/tl173l.html #12;
Technique to Collimate Ions in a Hall-Effect Thruster Discharge Chamber
Walker, Mitchell
Technique to Collimate Ions in a Hall-Effect Thruster Discharge Chamber Kunning G. Xu and Mitchell in the discharge chamber to repel ions away from the wall and focus them toward centerline. The electrodes repel ions with trajectories that intersect the chamber wall, which results in a more collimated ion exhaust
Paris-Sud XI, Université de
-temperature Hall effect in rare earth metals M. V. Vedernikov, V. G. Dvunitkin and N. I. Moreva A. F. Ioffe. Abstract. - Up to date the Hall effect in rare earth metals (REM) was studied rather extensively below at http://dx.doi.org/10.1051/jphyscol:1979518 #12;HIGH-TEMPERATURE HALL EFFECT IN RARE EARTH METALS C5
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
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.
Cobden, David
dox 25 nm and a range of effective channel dimensions L and W from 0.4 to 4 mm [9]. Each device on the metallic polysilicon gate: dr dVg C e 8.6 3 1011 cm22 V21 , where C eoxe0 dox and eox 3.9 [13
Sheath oscillation characteristics and effect on near-wall conduction in a krypton Hall thruster
Zhang, Fengkui, E-mail: fengkuizhang@163.com; Kong, Lingyi; Li, Chenliang; Yang, Haiwei; Li, Wei [College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001 (China)
2014-11-15T23:59:59.000Z
Despite its affordability, the krypton Hall-effect thruster in applications always had problems in regard to performance. The reason for this degradation is studied from the perspective of the near-wall conductivity of electrons. Using the particle-in-cell method, the sheath oscillation characteristics and its effect on near-wall conduction are compared in the krypton and xenon Hall-effect thrusters both with wall material composed of BNSiO{sub 2}. Comparing these two thrusters, the sheath in the krypton-plasma thruster will oscillate at low electron temperatures. The near-wall conduction current is only produced by collisions between electrons and wall, thereby causing a deficiency in the channel current. The sheath displays spatial oscillations only at high electron temperature; electrons are then reflected to produce the non-oscillation conduction current needed for the krypton-plasma thruster. However, it is accompanied with intensified oscillations.
arXiv:1007.2404v1[cond-mat.mes-hall]14Jul2010 Electrostatically defined Quantum Dots in a Si/SiGe
Ludwig-Maximilians-Universität, München
arXiv:1007.2404v1[cond-mat.mes-hall]14Jul2010 Electrostatically defined Quantum Dots in a Si/SiGe (QD) realized in a molecular beam epitaxy grown Si/SiGe heterostructure. Transport and charge as a spin qubit. Our results promise the suitability of electrostatically defined QDs in Si/SiGe
Effect of electron temperature anisotropy on near-wall conductivity in Hall thrusters
Zhang, Fengkui, E-mail: fengkuizhang@163.com, E-mail: yudaren@hit.edu.cn; Kong, Lingyi; Zhang, Xueyi; Li, Wei [College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001 (China); Yu, Daren, E-mail: fengkuizhang@163.com, E-mail: yudaren@hit.edu.cn [College of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)
2014-06-15T23:59:59.000Z
The electron velocity distribution in Hall thrusters is anisotropic, which not only makes the sheath oscillate in time, but also causes the sheath to oscillate in space under the condition of low electron temperatures. The spatial oscillation sheath has a significant effect on near-wall transport current. In this Letter, the method of particle-in-cell (2D?+?3?V) was adopted to simulate the effect of anisotropic electron temperatures on near-wall conductivity in a Hall thruster. Results show that the electron-wall collision frequency is within the same order in magnitude for both anisotropic and isotropic electron temperatures. The near-wall transport current produced by collisions between the electrons and the walls is much smaller than experimental measurements. However, under the condition of anisotropic electron temperatures, the non-collision transport current produced by slow electrons which reflected by the spatial oscillation sheath is much larger and closes to measurements.
Realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect
Ling, Xiaohui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421002 (China); Yi, Xunong [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zhou, Xinxing; Liu, Yachao; Shu, Weixing; Wen, Shuangchun [Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Luo, Hailu, E-mail: hailuluo@hnu.edu.cn [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China)
2014-10-13T23:59:59.000Z
We report the realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect. By breaking the rotational symmetry of a cylindrical vector beam, the intrinsic vortex phases that the two spin components of the vector beam carries, which is similar to the geometric Pancharatnam-Berry phase, are no longer continuous in the azimuthal direction, and leads to observation of spin accumulation at the opposite edge of the beam. Due to the inherent nature of the phase and independency of light-matter interaction, the observed photonic spin Hall effect is intrinsic. Modulating the topological charge of the vector beam, the spin-dependent splitting can be enhanced and the direction of spin accumulation is switchable. Our findings may provide a possible route for generation and manipulation of spin-polarized photons, and enables spin-based photonics applications.
Rivest, Christopher W. (Christopher Warren)
2006-01-01T23:59:59.000Z
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, ...
Quantum chaos and effective thermalization
Altland, Alexander
2011-01-01T23:59:59.000Z
We demonstrate effective equilibration for unitary quantum dynamics under conditions of classical chaos. Focusing on the paradigmatic example of the Dicke model, we show how a constructive description of the thermalization process is facilitated by the Glauber $Q$ or Husimi function, for which the evolution equation turns out to be of Fokker-Planck type. The equation describes a competition of classical drift and quantum diffusion in contractive and expansive directions. By this mechanism the system follows a 'quantum smoothened' approach to equilibrium, which avoids the notorious singularities inherent to classical chaotic flows.
Robert B. Laughlin and the Fractional Quantum Hall Effect
Office of Scientific and Technical Information (OSTI)
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Sandia Energy - Second Generation Fractional Quantum Hall Effect
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PREPRINT QUASIPARTICLE AGGREGATION I N THE FRACTIONAL QUANTUM HALL EFFECT
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Microscopic theory of quantum anomalous Hall effect in graphene (Journal
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Kovalev, Alexey A.; Tserkovnyak, Yaroslav; Vyborny, Karel; Sinova, Jairo.
2009-01-01T23:59:59.000Z
Transport theory for disordered multiple-band systems: Anomalous Hall effect and anisotropic magnetoresistance Alexey A. Kovalev,1,2 Yaroslav Tserkovnyak,1 Karel V?born?,3 and Jairo Sinova2,3 1Department of Physics and Astronomy, University... of California, Los Angeles, California 90095, USA 2Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA 3Institute of Physics, ASCR, Cukrovarnick? 10, 162 53 Praha 6, Czech Republic #1;Received 16 February 2009; revised...
Hall-effect-controlled gas dynamics in protoplanetary disks. I. Wind solutions at the inner disk
Bai, Xue-Ning, E-mail: xbai@cfa.harvard.edu [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)
2014-08-20T23:59:59.000Z
The gas dynamics of protoplanetary disks (PPDs) is largely controlled by non-ideal magnetohydrodynamic (MHD) effects including Ohmic resistivity, the Hall effect, and ambipolar diffusion. Among these the role of the Hall effect is the least explored and most poorly understood. In this series, we have included, for the first time, all three non-ideal MHD effects in a self-consistent manner to investigate the role of the Hall effect on PPD gas dynamics using local shearing-box simulations. In this first paper, we focus on the inner region of PPDs, where previous studies (Bai and Stone 2013; Bai 2013) excluding the Hall effect have revealed that the inner disk up to ?10 AU is largely laminar, with accretion driven by a magnetocentrifugal wind. We confirm this basic picture and show that the Hall effect modifies the wind solutions depending on the polarity of the large-scale poloidal magnetic field B{sub 0} threading the disk. When B{sub 0}??>0, the horizontal magnetic field is strongly amplified toward the disk interior, leading to a stronger disk wind (by ?50% or less in terms of the wind-driven accretion rate). The enhanced horizontal field also leads to much stronger large-scale Maxwell stress (magnetic braking) that contributes to a considerable fraction of the wind-driven accretion rate. When B{sub 0}??<0, the horizontal magnetic field is reduced, leading to a weaker disk wind (by ? 20%) and negligible magnetic braking. Under fiducial parameters, we find that when B{sub 0}??>0, the laminar region extends farther to ?10-15 AU before the magnetorotational instability sets in, while for B{sub 0}??<0, the laminar region extends only to ?3-5 AU for a typical accretion rate of ?10{sup –8} to10{sup –7} M {sub ?} yr{sup –1}. Scaling relations for the wind properties, especially the wind-driven accretion rate, are provided for aligned and anti-aligned field geometries.
Shakouri, Kh.; Peeters, F. M. [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium); Vasilopoulos, P.; Vargiamidis, V. [Department of Physics, Concordia University, 7141 Sherbrooke Ouest Montréal, Québec H4B 1R6 (Canada); Hai, G.-Q. [Instituto de Fisica de São Carlos, Universidade de São Paulo, São Carlos, SP 13560-970 (Brazil)
2014-05-26T23:59:59.000Z
We study the commensurability oscillations in silicene subject to a perpendicular electric field E{sub z}, a weak magnetic field B, and a weak periodic potential V=V{sub 0}cos(Cy),C=2?/a{sub 0} with a{sub 0} its period. The field E{sub z} and/or the modulation lift the spin degeneracy of the Landau levels and lead to spin and valley resolved Weiss oscillations. The spin resolution is maximal when the field E{sub z} is replaced by a periodic one E{sub z}=E{sub 0}cos(Dy),D=2?/b{sub 0}, while the valley one is maximal for b{sub 0}?=?a{sub 0}. In certain ranges of B values, the current is fully spin or valley polarized. Additional quantum Hall conductivity plateaux arise due to spin and valley intra-Landau-level transitions.
Quantum effects near future singularities
John D. Barrow; Antonio B. Batista; Giuseppe Dito; Julio C. Fabris; M. J. S. Houndjo
2012-01-09T23:59:59.000Z
General relativity allows a variety of future singularities to occur in the evolution of the universe. At these future singularities, the universe will end in a singular state after a finite proper time and geometrical invariants of the space time will diverge. One question that naturally arises with respect to these cosmological scenarios is the following: can quantum effects lead to the avoidance of these future singularities? We analyze this problem considering massless and conformally coupled scalar fields in an isotropic and homogeneous background leading to future singularities. It is shown that near strong, big rip-type singularities, with violation of the energy conditions, the quantum effects are very important, while near some milder classes of singularity like the sudden singularity, which preserve the energy conditions, quantum effects are irrelevant.
Inverse spin Hall effect induced by spin pumping into semiconducting ZnO
Lee, Jung-Chuan [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Huang, Leng-Wei [Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China); Hung, Dung-Shing, E-mail: dshung@mail.mcu.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Department of Information and Telecommunications Engineering, Ming Chuan University, Taipei 111, Taiwan (China); Chiang, Tung-Han [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Huang, J. C. A., E-mail: jcahuang@mail.ncku.edu.tw [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Liang, Jun-Zhi [Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Physics, Fu Jen Catholic University, Taipei 242, Taiwan (China); Lee, Shang-Fan, E-mail: leesf@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan (China)
2014-02-03T23:59:59.000Z
The inverse spin Hall effect (ISHE) of n-type semiconductor ZnO thin films with weak spin-orbit coupling has been observed by utilizing the spin pumping method. In the ferromagnetic resonance condition, the spin pumping driven by the dynamical exchange interaction of a permalloy film injects a pure spin current into the adjacent ZnO layer. This spin current gives rise to a DC voltage through the ISHE in the ZnO layer, and the DC voltage is proportional to the microwave excitation power. The effect is sizeable even when the spin backflow is considered.
Effective Field Theory of Fractional Quantized Hall Nematics (Journal
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Effective equations for quantum dynamics
Benjamin Schlein
2012-08-01T23:59:59.000Z
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.
Efimov effect in quantum magnets
Yusuke Nishida; Yasuyuki Kato; Cristian D. Batista
2013-08-23T23:59:59.000Z
Physics is said to be universal when it emerges regardless of the underlying microscopic details. A prominent example is the Efimov effect, which predicts the emergence of an infinite tower of three-body bound states obeying discrete scale invariance when the particles interact resonantly. Because of its universality and peculiarity, the Efimov effect has been the subject of extensive research in chemical, atomic, nuclear and particle physics for decades. Here we employ an anisotropic Heisenberg model to show that collective excitations in quantum magnets (magnons) also exhibit the Efimov effect. We locate anisotropy-induced two-magnon resonances, compute binding energies of three magnons and find that they fit into the universal scaling law. We propose several approaches to experimentally realize the Efimov effect in quantum magnets, where the emergent Efimov states of magnons can be observed with commonly used spectroscopic measurements. Our study thus opens up new avenues for universal few-body physics in condensed matter systems.
Knight, S; Darakchieva, V; Kühne, P; Carlin, J -F; Grandjean, N; Herzinger, C M; Schubert, M; Hofmann, T
2015-01-01T23:59:59.000Z
The effect of a tunable, externally coupled Fabry-P\\'{e}rot cavity to resonantly enhance the optical Hall effect signatures at terahertz frequencies produced by a traditional Drude-like two-dimensional electron gas is shown and discussed in this communication. As a result, the detection of optical Hall effect signatures at conveniently obtainable magnetic fields, for example by neodymium permanent magnets, is demonstrated. An AlInN/GaN-based high electron mobility transistor structure grown on a sapphire substrate is used for the experiment. The optical Hall effect signatures and their dispersions, which are governed by the frequency and the reflectance minima and maxima of the externally coupled Fabry-P\\'{e}rot cavity, are presented and discussed. Tuning the externally coupled Fabry-P\\'{e}rot cavity strongly modifies the optical Hall effect signatures, which provides a new degree of freedom for optical Hall effect experiments in addition to frequency, angle of incidence and magnetic field direction and stren...
Quantum Shock Waves - the case for non-linear effects in dynamics of electronic liquids
Eldad Bettelheim; Alexander G. Abanov; Paul Wiegmann
2006-06-29T23:59:59.000Z
Using the Calogero model as an example, we show that the transport in interacting non-dissipative electronic systems is essentially non-linear. Non-linear effects are due to the curvature of the electronic spectrum near the Fermi energy. As is typical for non-linear systems, propagating wave packets are unstable. At finite time shock wave singularities develop, the wave packet collapses, and oscillatory features arise. They evolve into regularly structured localized pulses carrying a fractionally quantized charge - {\\it soliton trains}. We briefly discuss perspectives of observation of Quantum Shock Waves in edge states of Fractional Quantum Hall Effect and a direct measurement of the fractional charge.
Quantum mechanical effects from deformation theory
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
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.
Nuclear quantum effects in water
Joseph A. Morrone; Roberto Car
2008-03-25T23:59:59.000Z
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.
Temperature-driven band inversion in Pb?.??Sn?.??Se: Optical and Hall-effect studies
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Anand, Naween [Univ. of Florida, Gainesville, FL (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Buvaev, Sanal [Univ. of Florida, Gainesville, FL (United States); Hebard, A. F. [Univ. of Florida, Gainesville, FL (United States); Tanner, D. B. [Univ. of Florida, Gainesville, FL (United States); Chen, Zhiguo [Florida State Univ., Tallahassee, FL (United States); Li, Zhiqiang [Florida State Univ., Tallahassee, FL (United States); Choudhary, Kamal [Univ. of Florida, Gainesville, FL (United States); Sinnott, S. B. [Univ. of Florida, Gainesville, FL (United States); Martin, C. [Ramapo College, Mahwah, NJ (United States)
2014-12-01T23:59:59.000Z
Optical and Hall-effect measurements have been performed on single crystals of Pb?.??Sn?.??Se, a IV-VI mixed chalcogenide. The temperature dependent (10–300 K) reflectance was measured over 40–7000 cm?¹ (5–870 meV) with an extension to 15,500 cm?¹ (1.92 eV) at room temperature. The reflectance was fit to the Drude-Lorentz model using a single Drude component and several Lorentz oscillators. The optical properties at the measured temperatures were estimated via Kramers-Kronig analysis as well as by the Drude-Lorentz fit. The carriers were p-type with the carrier density determined by Hall measurements. A signature of valence intraband transition is found in the low-energy optical spectra. It is found that the valence-conduction band transition energy as well as the free carrier effective mass reach minimum values at 100 K, suggesting temperature-driven band inversion in the material. Density function theory calculation for the electronic band structure also make similar predictions.
Temperature-driven band inversion in Pb?.??Sn?.??Se: Optical and Hall-effect studies
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Anand, Naween; Gu, Genda; Buvaev, Sanal; Hebard, A. F.; Tanner, D. B.; Chen, Zhiguo; Li, Zhiqiang; Choudhary, Kamal; Sinnott, S. B.; Martin, C.
2014-12-01T23:59:59.000Z
Optical and Hall-effect measurements have been performed on single crystals of Pb?.??Sn?.??Se, a IV-VI mixed chalcogenide. The temperature dependent (10–300 K) reflectance was measured over 40–7000 cm?¹ (5–870 meV) with an extension to 15,500 cm?¹ (1.92 eV) at room temperature. The reflectance was fit to the Drude-Lorentz model using a single Drude component and several Lorentz oscillators. The optical properties at the measured temperatures were estimated via Kramers-Kronig analysis as well as by the Drude-Lorentz fit. The carriers were p-type with the carrier density determined by Hall measurements. A signature of valence intraband transition is found in the low-energy opticalmore »spectra. It is found that the valence-conduction band transition energy as well as the free carrier effective mass reach minimum values at 100 K, suggesting temperature-driven band inversion in the material. Density function theory calculation for the electronic band structure also make similar predictions.« less
Temperature-driven band inversion in Pb?.??Sn?.??Se: Optical and Hall-effect studies
Anand, Naween [Univ. of Florida, Gainesville, FL (United States); Gu, Genda [Brookhaven National Lab. (BNL), Upton, NY (United States); Buvaev, Sanal [Univ. of Florida, Gainesville, FL (United States); Hebard, A. F. [Univ. of Florida, Gainesville, FL (United States); Tanner, D. B. [Univ. of Florida, Gainesville, FL (United States); Chen, Zhiguo [Florida State Univ., Tallahassee, FL (United States); Li, Zhiqiang [Florida State Univ., Tallahassee, FL (United States); Choudhary, Kamal [Univ. of Florida, Gainesville, FL (United States); Sinnott, S. B. [Univ. of Florida, Gainesville, FL (United States); Martin, C. [Ramapo College, Mahwah, NJ (United States)
2014-12-23T23:59:59.000Z
Optical and Hall-effect measurements have been performed on single crystals of Pb?.??Sn?.??Se, a IV-VI mixed chalcogenide. The temperature dependent (10–300 K) reflectance was measured over 40–7000 cm?¹ (5–870 meV) with an extension to 15,500 cm?¹ (1.92 eV) at room temperature. The reflectance was fit to the Drude-Lorentz model using a single Drude component and several Lorentz oscillators. The optical properties at the measured temperatures were estimated via Kramers-Kronig analysis as well as by the Drude-Lorentz fit. The carriers were p-type with the carrier density determined by Hall measurements. A signature of valence intraband transition is found in the low-energy optical spectra. It is found that the valence-conduction band transition energy as well as the free carrier effective mass reach minimum values at 100 K, suggesting temperature-driven band inversion in the material. Density function theory calculation for the electronic band structure also make similar predictions.
Skinner, T. D.; Olejnik, K.; Cunningham, L. K.; Kurebayashi, H.; Campion, R. P.; Gallagher, B. L.; Jungwirth, T.; Ferguson, A. J.
2015-03-31T23:59:59.000Z
spin Hall effect3 (SHE) is absorbed in the ferromagnet and induces the spin transfer torque4 (STT). In the other pic- ture, a non-equilibrium spin-density is generated via the relativistic inverse spin galvanic effect5 (ISGE) and induces the spin...
Wu Zhiwen; Liu Xiangyang; Wang Ningfei [School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China); Yu Daren [Harbin Plasma Propulsion Lab, Mail Box 458, Harbin Institute of Technology, Harbin 150001 (China)
2010-07-15T23:59:59.000Z
The effect of magnetic lens on the electron current due to near wall conductivity (NWC) in a Hall thruster is studied. A Monte Carlo model is employed to simulate the effect of the large magnetic field incidence angle on the electron current. The simulation results show that the electron current due to NWC decreases in the case of large incidence. The simulation qualitatively agrees with the related experimental result. And the simulation also demonstrates that choosing the curvature angle of the magnetic field is also a key factor to design a Hall thruster with high operation performance.
Effects of magnetic field strength on the low frequency oscillation in Hall thrusters
Wang Chunsheng; Wei Liqiu; Ning Zhongxi; Yu Daren [Laboratory of Plasma Propulsion, Mail Box 458, Harbin Institute of Technology, Harbin 150001 (China)
2011-01-15T23:59:59.000Z
In order to study the effect of magnetic field strength on low frequency oscillation in Hall thrusters, experiments were carried out with different operating parameters. Experimental results show that the effect of magnetic field strength on the low frequency oscillation changes with operating parameters. In the decline zone of magnetoampere characteristic curve, low frequency oscillation increases with the increase of magnetic field strength at low mass flow rate, while decreases with the increase of magnetic field strength at high mass flow rate. With further experiments and numerical simulations, it is found that the change of electron current at low mass flow rate and the change of ion current at high mass flow rate account for the variations of low frequency oscillation. Finally, the physical analysis is performed.
3D Quantum Gravity and Effective Noncommutative Quantum Field Theory
Freidel, Laurent; Livine, Etera R. [Perimeter Institute, 31 Caroline Street, North Waterloo, Ontario N2L 2Y5, Canada, and Laboratoire de Physique, ENS Lyon, CNRS UMR 5672, 46 Allee d'Italie, 69364 Lyon Cedex 07 (France)
2006-06-09T23:59:59.000Z
We show that the effective dynamics of matter fields coupled to 3D quantum gravity is described after integration over the gravitational degrees of freedom by a braided noncommutative quantum field theory symmetric under a {kappa} deformation of the Poincare group.
Dynamical Casimir Effect in Quantum Information Processing
Giuliano Benenti; Antonio D'Arrigo; Stefano Siccardi; Giuliano Strini
2014-07-28T23:59:59.000Z
We demonstrate, in the regime of ultrastrong matter-field coupling, the strong connection between the dynamical Casimir effect (DCE) and the performance of quantum information protocols. Our results are illustrated by means of a realistic quantum communication channel and show that the DCE is a fundamental limit for quantum computation and communication and that novel schemes are required to implement ultrafast and reliable quantum gates. Strategies to partially counteract the DCE are also discussed.
Disorder effects in the anomalous Hall effect induced by Berry curvature RID B-5617-2009
Sinitsyn, NA; Niu, Q.; Sinova, Jairo; Nomura, K.
2005-01-01T23:59:59.000Z
#1;R2DEG#2; with smooth disorder, where the time- reversal symmetry is broken by an out-of-plane Zeeman field. In the diluted magnetic semiconductors the Berry cur- vature is strongly momentum dependent. This separates para- metrically the clean... that early results, like that of the Lutting- er?s sign reversal prediction, cannot be used directly for new applications such as diluted magnetic semiconductors, where the Berry curvature is strongly momentum dependent. Our prediction for the Hall...
PIC simulation of SPT Hall thrusters : high power operation and wall effects
Sullivan, Kay Ueda, 1980-
2004-01-01T23:59:59.000Z
The fully kinetic Hall Thruster simulation built by [1] and used by [2] is further refined and used to obtain results for the P5 SPT Hall thruster at 3kw and 5kw operation. Performance data agree well with experiments [3], ...
"Exotic" quantum effects in the laboratory?
Ralf Schützhold
2010-04-15T23:59:59.000Z
This Article provides a brief (non-exhaustive) review of some recent developments regarding the theoretical and possibly experimental study of "exotic" quantum effects in the laboratory with special emphasis on cosmological particle creation, Hawking radiation, and the Unruh effect.
Quantum Field Theory in Graphene
I. V. Fialkovsky; D. V. Vassilevich
2011-11-18T23:59:59.000Z
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.
Formation of quantum spin Hall state on Si surface and energy gap scaling with
Simons, Jack
on a semiconductor surface, based on first-principles calculations and effective Hamiltonian analysis. We show is to directly fabricate large-gap TIs on semiconductor surfaces, which may avoid problems like transfer . Recent studies pertaining to Bi/Sb(111) films1417 , Sn films18 , metal-decorated graphene19
Parallelization of particle-in-cell simulation modeling Hall-effect thrusters
Fox, Justin M., 1981-
2005-01-01T23:59:59.000Z
MIT's fully kinetic particle-in-cell Hall thruster simulation is adapted for use on parallel clusters of computers. Significant computational savings are thus realized with a predicted linear speed up efficiency for certain ...
Understanding the physics of a possible non-Abelian fractional quantum hall
Office of Scientific and Technical Information (OSTI)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect1.08]Te[subscriptM-PACEResponseseffect state. (Technical Report) | SciTech Connecteffect
Hankiewicz, EM; Li, J.; Jungwirth, T.; Niu, Q.; Shen, SQ; Sinova, Jairo.
2005-01-01T23:59:59.000Z
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...
Large anomalous Hall effect in ferromagnetic insulator-topological insulator heterostructures
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
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.
Effects of Hall current and electron temperature anisotropy on proton fire-hose instabilities
Hau, L.-N. [Institute of Space Science, National Central University, Jhongli, Taiwan (China) [Institute of Space Science, National Central University, Jhongli, Taiwan (China); Department of Physics, National Central University, Jhongli, Taiwan (China); Wang, B.-J. [Institute of Space Science, National Central University, Jhongli, Taiwan (China) [Institute of Space Science, National Central University, Jhongli, Taiwan (China); Institute of Astronomy, National Central University, Jhongli, Taiwan (China)
2013-10-15T23:59:59.000Z
The standard magnetohydrodynamic (MHD) theory predicts that the Alfvén wave may become fire-hose unstable for ?{sub ?}??{sub ?}>2. In this study, we examine the proton fire-hose instability (FHI) based on the gyrotropic two-fluid model, which incorporates the ion inertial effects arising from the Hall current and electron temperature anisotropy but neglects the electron inertia in the generalized Ohm's law. The linear dispersion relation is derived and analyzed which in the long wavelength approximation, ?{sub i}k?0 or ?{sub e}=?{sub 0}(p{sub ?,e}?p{sub ?,e})/B{sup 2}=1, recovers the ideal MHD model with separate temperature for ions and electrons. Here, ?{sub i} is the ion inertial length and k is the wave number. For parallel propagation, both ion cyclotron and whistler waves become propagating and growing for ?{sub ?}??{sub ?}>2+?{sub i}{sup 2}k{sup 2}(?{sub e}?1){sup 2}/2. For oblique propagation, the necessary condition for FHI remains to be ?{sub ?}??{sub ?}>2 and there exist one or two unstable fire-hose modes, which can be propagating and growing or purely growing. For large ?{sub i}k values, there exists no nearly parallel FHI leaving only oblique FHI and the effect of ?{sub e}>1 may greatly enhance the growth rate of parallel and oblique FHI. The magnetic field polarization of FHI may be reversed due to the sign change associated with (?{sub e}?1) and the purely growing FHI may possess linear polarization while the propagating and growing FHI may possess right-handed or left-handed polarization.
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...
Optimal tunneling enhances the quantum photovoltaic effect in double quantum dots
Wang, Chen
We investigate the quantum photovoltaic effect in double quantum dots by applying the nonequilibrium quantum master equation. A drastic suppression of the photovoltaic current is observed near the open circuit voltage, ...
Dependence of the intrinsic spin-Hall effect on spin-orbit interaction character RID B-5617-2009
Nomura, K.; Sinova, Jairo; Sinitsyn, NA; MacDonald, AH.
2005-01-01T23:59:59.000Z
. DOI: 10.1103/PhysRevB.72.165316 PACS number?s?: 73.50.Fq, 72.10.?d, 73.21.?b I. INTRODUCTION Interest in spintronics1?6 has been heightened by the tech- nological impact of ferromagnetic metal-based devices and by ferromagnetic semiconductor... materials advances. Theo- retical attention has recently focused on spintronics effects in paramagnetic materials, and in particular on the spin-Hall ?SH? effect,7 in which an electric field induces a transverse spin current. Murakami et al.8 and Sinova...
WIGNER MOLECULES IN SEMICONDUCTOR QUANTUM DOTS AND TRAPPED ULTRACOLD BOSONIC CLOUDS
Yannouleas, Constantine
WIGNER MOLECULES IN SEMICONDUCTOR QUANTUM DOTS AND TRAPPED ULTRACOLD BOSONIC CLOUDS Constantine], with a focus on the strongly correlated regime of electrons in two-dimensional semiconductor quantum dots (QDs dot [3]; (3) fractional-quantum-Hall-effect analogies and differences in graphene quantum dots at zero
Nonlinear effect on quantum control for two-level systems
W. Wang; J. Shen; X. X. Yi
2009-06-05T23:59:59.000Z
The traditional quantum control theory focuses on linear quantum system. Here we show the effect of nonlinearity on quantum control of a two-level system, we find that the nonlinearity can change the controllability of quantum system. Furthermore, we demonstrate that the Lyapunov control can be used to overcome this uncontrollability induced by the nonlinear effect.
On the Rôle of a Torsion-like Field in a Scenario for the Spin Hall Effect
C. F. L. Godinho; J. A. Helayël Neto
2014-12-13T23:59:59.000Z
Starting from an action that describes a Dirac fermion, we propose and analyze a model based on a low-relativistic Pauli equation coupled to a torsion-like term to study Spin Hall Effect (SHE). We point out a very particular connection between the modified Pauli equation and the (SHE), where what we refer to torsion as field playing an important r\\^ole in the spin-orbit coupling process. In this scenario, we present a proposal of a spin-type current, considering the tiny contributions of torsion in connection with geometrical properties of the material.
Wall current closure effects on plasma and sheath fluctuations in Hall thrusters
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
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.
Demir, Hilmi Volkan
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
Effective Evolution Equations from Quantum Dynamics
Niels Benedikter; Marcello Porta; Benjamin Schlein
2015-02-09T23:59:59.000Z
In these notes we review the material presented at the summer school on "Mathematical Physics, Analysis and Stochastics" held at the University of Heidelberg in July 2014. We consider the time-evolution of quantum systems and in particular the rigorous derivation of effective equations approximating the many-body Schr\\"odinger dynamics in certain physically interesting regimes.
Shepelyansky, Dima
into electricity and has important appli- cations in photodiodes and photovoltaic cells. Recently, significantarXiv:1101.5667v1[cond-mat.mes-hall]29Jan2011 Resonant Photovoltaic Effect in Surface as an electromotive force (EMF), to develop across the system. In semicon- ductors, such a photovoltaic effect can
Hankiewicz, EM; Li, J.; Jungwirth, T.; Niu, Q.; Shen, SQ; Sinova, Jairo.
2005-01-01T23:59:59.000Z
-current response generated perpendicular to the driving electric field. Recently, the spin Hall effect was experimentally ob- served by Kato et al.6 in n-doped GaAs using the Kerr effect and by Wunderlich et al.7 in the p-n junction light-emitting diodes based...
Effect of trapping in degenerate quantum plasmas
Shah, H. A.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Salam Chair, GC University, Lahore 54000 (Pakistan)
2010-03-15T23:59:59.000Z
In the present work we consider the effect of trapping as a microscopic process in a plasma consisting of quantum electrons and nondegenerate ions. The formation of solitary structures is investigated in two cases: first when the electrons are fully degenerate and second when small temperature effects are taken into account. It is seen that not only rarefactive but coupled rarefactive and compressive solitons are obtained under different temperature conditions.
Quantum anti-Zeno effect in artificial quantum systems
Qing Ai; Jie-Qiao Liao; C. P. Sun
2010-03-24T23:59:59.000Z
In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloch electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove's singularities and the effects of the counter-rotating terms.
Effect of local filtering on Freezing Phenomena of Quantum Correlation
Sumana Karmakar; Ajoy Sen; Amit Bhar; Debasis Sarkar
2015-04-20T23:59:59.000Z
General quantum correlations measures like quantum discord, one norm geometric quantum discord, exhibit freezing, sudden change, double sudden change behavior in their decay rates under different noisy channels. Therefore, one may attempt to investigate how the freezing behavior and other dynamical features are affected under application of local quantum operations. In this work, we demonstrate the effect of local filtering on the dynamical evolution of quantum correlations. We have found that using local filtering one may remove freezing depending upon the filtering parameter.
Quantum gravity effects in the Kerr spacetime
Reuter, M. [Institute of Physics, University of Mainz, Staudingerweg 7, D-55099 Mainz (Germany); Tuiran, E. [Departamento de Fisica, Universidad del Norte, Km 5 via a Puerto Colombia, AA-1569 Barranquilla (Colombia)
2011-02-15T23:59:59.000Z
We analyze the impact of the leading quantum gravity effects on the properties of black holes with nonzero angular momentum by performing a suitable renormalization group improvement of the classical Kerr metric within quantum Einstein gravity. In particular, we explore the structure of the horizons, the ergosphere, and the static limit surfaces as well as the phase space available for the Penrose process. The positivity properties of the effective vacuum energy-momentum tensor are also discussed and the 'dressing' of the black hole's mass and angular momentum are investigated by computing the corresponding Komar integrals. The pertinent Smarr formula turns out to retain its classical form. As for their thermodynamical properties, a modified first law of black-hole thermodynamics is found to be satisfied by the improved black holes (to second order in the angular momentum); the corresponding Bekenstein-Hawking temperature is not proportional to the surface gravity.
Magnetic percolation and giant spontaneous Hall effect in La1 xCaxCoO3 ,,0.2 x 0.5... A. V. Samoilov
Yeh, Nai-Chang
Magnetic percolation and giant spontaneous Hall effect in La1 xCaxCoO3 ,,0.2 x 0.5... A. V and Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute Technology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
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...
Yu Daren; Li Hong; Ning Zhongxi; Yan Guojun [Laboratory of Plasma Propulsion, Mail Box 458, Harbin Institute of Technology, Harbin 150001 (China); Wu Zhiwen [School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083 (China)
2009-10-15T23:59:59.000Z
An experiment has been made to investigate the effect of curved magnetic field topology on near wall conductivity in the ion acceleration region of Hall thrusters. The experimental results show that the electron current due to near wall conductivity is of the minimum in the case of focused topology and increases in the cases of both less-focus and over-focus topologies. This finding cannot be explained properly by the magnetic mirror effect, which is the one and only reported effect related to the magnetic field curvature so far. Based on the analysis of interaction between the plasma and the wall, a new physical effect is proposed. The difference of magnetic field topology causes different electric potential distribution, leads to different ion flux to the wall, results in the change of sheath property and secondary electron emission, and finally affects the electron current due to near wall conductivity. This effect is further justified by the agreement between the experiment and simulation which is performed with a particle-in-cell model. Therefore, we conclude that the ion flow injection is a significant effect to near wall conductivity in the scope of curved magnetic field topology besides the magnetic mirror effect. Moreover, we find that the focus topology of magnetic field is favorable to obtain a high thruster performance from both the ion acceleration aspect and the electron conduction aspect and so is useful practically for thruster optimization.
Quantum confined Stark effect in Gaussian quantum wells: A tight-binding study
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
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.
Bing Concert Hall, under construction
Houses Schwab Residential Center Lyman Graduate Residences Sterling Quad Mirrielees Pearce Mitchell Godzilla Thornton Center Bambi Roble Gym Terman Engineering Center Forsythe Hall Spruce Hall Cypress Hall
The effective field theory treatment of quantum gravity
Donoghue, John F. [Department of Physics, University of Massachusetts, Amherst, MA 01003 (United States)
2012-09-24T23:59:59.000Z
This is a pedagogical introduction to the treatment of quantum general relativity as an effective field theory. It starts with an overview of the methods of effective field theory and includes an explicit example. Quantum general relativity matches this framework and I discuss gravitational examples as well as the limits of the effective field theory. I also discuss the insights from effective field theory on the gravitational effects on running couplings in the perturbative regime.
Weightlessness of photons: A quantum effect
Ari Brynjolfsson
2006-02-17T23:59:59.000Z
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.
Busemeyer, Jerome R.
A skeptic would argue that it is quite a speculative leap to think that quantum probability can be appliedQuantum Model of Question Order Effects 1 Empirical test of a quantum probability model, 154 N. Oval Columbus, OH 43210 voice: (614) 247-8031 #12;Quantum Model of Question Order Effects 2
2D massless QED Hall half-integer conductivity and graphene
A. Pérez Martínez; E. Rodriguez Querts; H. Pérez Rojas; R. Gaitan; S. Rodriguez Romo
2011-10-13T23:59:59.000Z
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.
The Effects of Quantum Entropy on the Bag Constant
Miller, D E; Miller, David E.; Tawfik, Abdel-Nasser
2003-01-01T23:59:59.000Z
The effects of quantum entropy on the bag constant are studied at low temperatures and small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, $\\Delta$ and $\\Omega^-$. In both cases we have found that the bag constant without the quantum entropy almost does not change with the temperature and the quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant.
Quantum anomalous Hall effect with cold atoms trapped in a square lattice
Liu, Xiong-Jun; Liu, Xin; Wu, Congjun; Sinova, Jairo
2010-01-01T23:59:59.000Z
-JUN LIU, XIN LIU, CONGJUN WU, AND JAIRO SINOVA PHYSICAL REVIEW A 81, 033622 (2010) represent the edge and bulk states, respectively. The light Bragg scattering directly measures the dynamical structure factor [23]: S(q, ?) = ? ky1 ,ky2 { 1? f [E...| #1; q0 the dynamical structure takes the general form S(q, ?) ? (|q| + ky0 )#5;2?(? ? vF q) + #8;0 ?#5;20 2t2aba2 1+ 3h???/(2q0atab) [1+ h???/(q0atab)]2 ? ( pi 2 + sin?1 ?1/2|q ? q0|? h??? ) #15;(? ? ?c), (11) where ?? = ? ?#8;0/2h...
Observation of the Integer Quantum Hall Effect in Record High-Mobility
Office of Scientific and Technical Information (OSTI)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article:UsingMesonSpeedingSpeeding access toSpeeding(Journal Article)
Emergent and reentrant fractional quantum Hall effect in trilayer systems in a tilted magnetic field
Gusev, Guennady
field G. M. Gusev,1 S. Wiedmann,2,3 O. E. Raichev,4 A. K. Bakarov,5 and J. C. Portal2,3,6 1Instituto de Physics, Novosibirsk 630090, Russia 6 Institut Universitaire de France, 75005 Paris, France Received 28
Non-abelian fractional quantum hall effect for fault-resistant topological
Office of Scientific and Technical Information (OSTI)
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Non-abelian fractional quantum hall effect for fault-resistant topological
Office of Scientific and Technical Information (OSTI)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article:UsingMeson tomaterials :Newton's Methodquantum computation. (Technicalquantum
Fractional Quantum Hall Effect at Landau Level Filling v=4/11. (Journal
Office of Scientific and Technical Information (OSTI)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect Journal Article: DiscreteFELIX: Thenerve agent reaction(JournalSciTechSciTechArticle)
Topological Hubbard Model and Its High-Temperature Quantum Hall Effect
Office of Scientific and Technical Information (OSTI)
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), 2002; Level:5 TablesExports to3,1,50022,3,,0,,6,1,SeparationConnect1.08]Te[subscriptM-PACEResponses to a Warming Climate|(TechnicalsystemsArticle) |Top(Journal
Dennett, Daniel
Carpenter House 176 Curtis Wilson BlakesleeBlakeslee Sawyer Office Services Hallowell Hall Blakely Elliot-Pearson Child Dev. Centr. Elliot-Pearson Child Dev. Centr. Robinson Hall Hamilton Pool Halligan Hall Paige Hall
Imperfection effects for multiple applications of the quantum wavelet transform
Marcello Terraneo; Dima L. Shepelyansky
2003-03-09T23:59:59.000Z
We study analytically and numerically the effects of various imperfections in a quantum computation of a simple dynamical model based on the Quantum Wavelet Transform (QWT). The results for fidelity timescales, obtained for a large range of error amplitudes and number of qubits, imply that for static imperfections the threshold for fault-tolerant quantum computation is decreased by a few orders of magnitude compared to the case of random errors.
EPR, Bell, Schrodinger's cat, and the Monty Hall Paradox
Doron Cohen
2007-04-09T23:59:59.000Z
The purpose of this manuscript is to provide a short pedagogical explanation why "quantum collapse" is not a metaphysical event, by pointing out the analogy with a "classical collapse" which is associated with the Monty Hall Paradox.
Quantum Transport Effects and Coherent Ultrafast Multidimensional...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of light harvesting and open up applications to quantum computing and information processing stemming from entanglement of chromophores. Exciton dynamics simulations in the...
Carlos III de Madrid, Universidad
American Institute of Aeronautics and Astronautics 1 Magnetic field effects on secondary electron, CT AIAA 2008-4725 Copyright © 2008 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. #12;American Institute of Aeronautics and Astronautics 2 Figure 1. Sketch
A study of Quantum Correlation for Three Qubit States under the effect of Quantum Noisy Channels
Pratik K. Sarangi; Indranil Chakrabarty
2014-11-27T23:59:59.000Z
We study the dynamics of quantum dissension for three qubit states in various dissipative channels such as amplitude damping, dephasing and depolarizing. Our study is solely based on Markovian environments where quantum channels are without memory and each qubit is coupled to its own environment. We start with mixed GHZ, mixed W, mixture of separable states, a mixed biseparable state, as the initial states and mostly observe that the decay of quantum dissension is asymptotic in contrast to sudden death of quantum entanglement in similar environments. This is a clear indication of the fact that quantum correlation in general is more robust against the effect of noise. However, for a given class of initial mixed states we find a temporary leap in quantum dissension for a certain interval of time. More precisely, we observe the revival of quantum correlation to happen for certain time period. This signifies that the measure of quantum correlation such as quantum discord, quantum dissension, defined from the information theoretic perspective is different from the correlation defined from the entanglement-separability paradigm and can increase under the effect of the local noise. We also study the effects of these channels on the monogamy score of each of these initial states. Interestingly, we find that for certain class of states and channels, there is change from negative values to positive values of the monogamy score with classical randomness as well as with time. This gives us an important insight in obtaining states which are freely sharable (polygamous state) from the states which are not freely sharable (monogamous). This is indeed a remarkable feature, as we can create monogamous states from polygamous states Monogamous states are considered to have more signatures of quantum ness and can be used for security purpose.
TRINITY HALL PUBLICATION SCHEME
Lasenby, Joan
TRINITY HALL PUBLICATION SCHEME PART 2 Main categories The main groups of classes of information Trinity Hall was founded in 1350 by William Bateman, Bishop of Norwich, as a common law corporation to the University and College Statutes. The Education (Listed Bodies) Order 1997 recognises Trinity Hall
Capogna, Luca
2014 - 2015 Residence Hall Handbook #12;2014-2015 RESIDENCE HALL HANDBOOK The policies Shooter Guidelines 38 2.21 Sustainable Living Tips for Residence Hall Students 39 2.22 Campus Commons 40 3 printing, editing and any revisions, additions or deletions during the course of the year easier to manage
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
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.
Holographic Spontaneous Parity Breaking and Emergent Hall Viscosity and Angular Momentum
Dam Thanh Son; Chaolun Wu
2014-08-30T23:59:59.000Z
We study the spontaneous parity breaking and generating of Hall viscosity and angular momentum in holographic p+ip model, which can describe strongly-coupled chiral superfluid states in many quantum systems. The dual gravity theory, an SU(2) gauge field minimally coupled to Einstein gravity, is parity-invariant but allows a black hole solution with vector hair corresponding to a parity-broken superfluid state. We show that this state possesses a non-vanishing parity-odd transport coefficient -- Hall viscosity -- and an angular momentum density. We first develop an analytic method to solve this model near the critical regime and to take back-reactions into account. Then we solve the equation for the tensor mode fluctuations and obtain the expression for Hall viscosity via Kubo formula. We also show that a non-vanishing angular momentum density can be obtained through the vector mode fluctuations and the corresponding boundary action. We give analytic results of both Hall viscosity and angular momentum density near the critical regime in terms of physical parameters. The near-critical behavior of Hall viscosity is different from that obtained from a gravitational Chern-Simons model. We find that the magnitude of Hall viscosity to angular momentum density ratio is numerically consistent with being equal to 1/2 at large SU(2) coupling corresponding to the probe limit, in agreement with previous results obtained for various quantum fluid systems and from effective theory approaches. In addition, we find the shear viscosity to entropy density ratio remains above the universal bound.
Monte Carlo simulation of quantum Zeno effect in the brain
Danko Georgiev
2014-12-11T23:59:59.000Z
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.
Hall conductance and topological invariant for open systems
H. Z. Shen; W. Wang; X. X. Yi
2014-10-07T23:59:59.000Z
The Hall conductivity given by the Kubo formula is a linear response of the quantum transverse transport to a weak electric field. It has been intensively studied for a quantum system without decoherence, but it is barely explored for systems subject to decoherence. In this paper, we develop a formalism to deal with this issue for topological insulators. The Hall conductance for a topological insulator coupled to an environment is derived, the derivation is based on a linear response theory of open system. As an application, the Hall conductance of a two-band topological insulator and a two-dimensional lattice is presented and discussed.
Two quantum effects in the theory of gravitation
Robinson, Sean Patrick, 1977-
2005-01-01T23:59:59.000Z
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 ...
Gusev, Guennady
,2,3, G. M. Gusev4, A. K. Bakarov5, and J. C. Portal2,3 1 Radboud University Nijmegen, Institute~ao Paulo, SP, Brazil 5 Institute of Semiconductor Physics, Novosibirsk 630090, Russia E-mail: s
Quantum Effects in Photosynthesis | MIT-Harvard Center for Excitonics
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
quantum information and theory of quantum computation; dynamics of open quantum systems; theory of decoherence; quantum control, quantum nanoscale systems, including trapped cold...
Low-Energy Effective Theories of Quantum Link and Quantum Spin Models
B. Schlittgen; U. -J. Wiese
2000-12-11T23:59:59.000Z
Quantum spin and quantum link models provide an unconventional regularization of field theory in which classical fields arise via dimensional reduction of discrete variables. This D-theory regularization leads to the same continuum theories as the conventional approach. We show this by deriving the low-energy effective Lagrangians of D-theory models using coherent state path integral techniques. We illustrate our method for the $(2+1)$-d Heisenberg quantum spin model which is the D-theory regularization of the 2-d O(3) model. Similarly, we prove that in the continuum limit a $(2+1)$-d quantum spin model with $SU(N)_L\\times SU(N)_R\\times U(1)_{L=R}$ symmetry is equivalent to the 2-d principal chiral model. Finally, we show that $(4+1)$-d SU(N) quantum link models reduce to ordinary 4-d Yang-Mills theory.
TRINITY HALL Trinity Hall, Dartry Road, Dublin 6,
O'Mahony, Donal E.
TRINITY HALL Trinity Hall, Dartry Road, Dublin 6, Ireland. Tel +353-1-4971772 E-Mail: trinity.hall@tcd.ie & warden@tcd.ie www.wardentrinityhall.tcdlife.ie/ RESIDENTS HANDBOOK 2010/2011 TRINITY HALL Students are advised to read this information in conjunction with the Conditions of Occupancy Trinity Hall 2010
Characterization of control noise effects in optimal quantum unitary dynamics
David Hocker; Constantin Brif; Matthew D. Grace; Ashley Donovan; Tak-San Ho; Katharine Moore Tibbetts; Rebing Wu; Herschel Rabitz
2014-11-13T23:59:59.000Z
This work develops measures for quantifying the effects of field noise upon targeted unitary transformations. Robustness to noise is assessed in the framework of the quantum control landscape, which is the mapping from the control to the unitary transformation performance measure (quantum gate fidelity). Within that framework, a new geometric interpretation of stochastic noise effects naturally arises, where more robust optimal controls are associated with regions of small overlap between landscape curvature and the noise correlation function. Numerical simulations of this overlap in the context of quantum information processing reveal distinct noise spectral regimes that better support robust control solutions. This perspective shows the dual importance of both noise statistics and the control form for robustness, thereby opening up new avenues of investigation on how to mitigate noise effects in quantum systems.
J. E. Avron; A. Elgart; G. M. Graf; L. Sadun
2001-07-12T23:59:59.000Z
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.
Borunda, M. F.; Liu, Xin; Kovalev, Alexey A.; Liu, Xiong-Jun; Jungwirth, T.; Sinova, Jairo.
2008-01-01T23:59:59.000Z
We study the quantum interference effects induced by the Aharonov-Casher phase in asymmetrically confined two-dimensional electron and heavy-hole ring structure systems, taking into account the electrically tunable spin-orbit (SO) interaction. We...
Quantum effects after decoherence in a quenched phase transition
Nuno D. Antunes; Fernando C. Lombardo; Diana Monteoliva
2001-10-30T23:59:59.000Z
We study a quantum mechanical toy model that mimics some features of a quenched phase transition. Both by virtue of a time-dependent Hamiltonian or by changing the temperature of the bath we are able to show that even after classicalization has been reached, the system may display quantum behaviour again. We explain this behaviour in terms of simple non-linear analysis and estimate relevant time scales that match the results of numerical simulations of the master-equation. This opens new possibilities both in the study of quantum effects in non-equilibrium phase transitions and in general time-dependent problems where quantum effects may be relevant even after decoherence has been completed.
An Equation of Motion with Quantum Effect in Spacetime
Jyh-Yang Wu
2009-05-26T23:59:59.000Z
In this paper, we shall present a new equation of motion with Quantum effect in spacetime. To do so, we propose a classical-quantum duality. We also generalize the Schordinger equation to the spacetime and obtain a relativistic wave equation. This will lead a generalization of Einstein's formula $E=m_0c^2$ in the spacetime. In general, we have $E=m_0c^2 + \\frac{\\hbar^2}{12m_0}R$ in a spacetime.
Polymer quantum effects on compact stars models
Guillermo Chacon-Acosta; Hector Hernandez-Hernandez
2014-08-05T23:59:59.000Z
In this work we study a completely degenerated fermion gas at zero temperature within a semiclassical approximation for the Hamiltonian arising in polymer quantum mechanics. Polymer quantum systems are quantum mechanical models quantized in a similar way as in loop quantum gravity that allow the study of the discreteness of space and other features of the loop quantization in a simplified way. We obtain the polymer modified thermodynamical properties noticing that the corresponding Fermi energy is exactly the same as if one directly polymerizes the momentum $p_F$. We also obtain the corresponding expansion of thermodynamical variables for small values of the polymer length scale $\\lambda$. With this results we study a simple model of a compact object where the gravitational collapse is supported by electron degeneracy pressure. We find polymer corrections to the mass of the star. When compared with typical measurements of the mass of white dwarfs we obtain a bound on the polymer length of $\\lambda^2\\lesssim 10^{-26}m^2$.
Quantum Coherence Effects in Novel Quantum Optical Systems
Sete, Eyob Alebachew
2012-10-19T23:59:59.000Z
. . . . . . . . . . . . . . . . . . . . . 50 b. N atoms: R #29; ? . . . . . . . . . . . . . . . . . . 52 3. A delta function ingression . . . . . . . . . . . . . . . 53 C. The effect of virtual processes on single photon Dicke superradiance... qubits . . . . . . . 73 1. Initial pure state . . . . . . . . . . . . . . . . . . . . . 73 2. Initial mixed state . . . . . . . . . . . . . . . . . . . . 79 E. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 V ENTANGLEMENT OF TWO...
Quantum origin of an anomalous isotope effect in ozone formation
Reid, Scott A.
Quantum origin of an anomalous isotope effect in ozone formation D. Babikov *, B.K. Kendrick, R mechanical calculations of the ðJ ¼ 0Þ energies and lifetimes of the metastable states of ozone on a new effect in the reaction that forms ozone because of their role in the energy transfer mechanism, in which
Quantum Electrodynamical Effects in Dusty Plasmas
M. Marklund; L. Stenflo; P. K. Shukla; G. Brodin
2005-05-31T23:59:59.000Z
A new nonlinear electromagnetic wave mode in a magnetized dusty plasma is predicted. Its existence depends on the interaction of an intense circularly polarized electromagnetic wave with a dusty plasma, where quantum electrodynamical photon-photon scattering is taken into account. Specifically, we consider a dusty electron-positron-ion plasma, and show that the propagation of the new mode is admitted. It could be of significance for the physics of supernova remnants and in neutron star formation.
Bogyo, Matthew
Gardens Braun Music Center The Knoll Bechtel International Center Post Office Clubhouse Old Union 590 500 Truck Hse. Clock Tower Owen Bolivar House Haas Center Galvez Modular Sweet Hall Bookstore Law School. Hoover Tower Cummings Art Art Gallery Manzanita Dining Commons Burnham Pavilion Ford Center Montag Hall
Unknown
2009-01-01T23:59:59.000Z
Measurements of the Hall coefficient and resistivity for highly oriented Tl2Ba2CaCu2O8+delta thin films are reported. The temperature dependence of cotTHETA(H), where THETA(H) is the normal-state Hall angle, for a single-phase (2:2:1:2) film sample...
TRINITY HALL PUBLICATION SCHEME
Lasenby, Joan
TRINITY HALL PUBLICATION SCHEME PART 1 INTRODUCTION 1. Legal requirement 1.1 Adopting a publication and whether or not charges will be made. 3. The `model' publication scheme for higher education 3.1 Trinity and is committed to publishing the information it describes. 4. Who we are 4.1 Trinity Hall is a college within
Sinitsyn, N. A.; MacDonald, A. H.; Jungwirth, T.; Dugaev, V. K.; Sinova, Jairo.
2007-01-01T23:59:59.000Z
The anomalous Hall effect (AHE) is a consequence of spin-orbit coupling in a ferromagnetic metal and related primarily to density-matrix response to an electric field that is off-diagonal in band index. For this reason disorder contributions...
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
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
Report over the experimental activities in Hall A at Thomas Jefferson National Accelerator Facility during 2013.
Macroscopic quantum tunneling and the 'cosmic' Josephson effect
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
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.
Effects of Quantum Confinement on the Doping Limit of Semiconductor
Wu, Junqiao
Effects of Quantum Confinement on the Doping Limit of Semiconductor Nanowires D. R. Khanal,, Joanne concentrations in semiconductor nanowires. Our calculations are based on the amphoteric defect model, which describes the thermodynamic doping limit in semiconductors in terms of the compensation of external dopants
Tunneling in Polymer Quantization and the Quantum Zeno Effect
Durmus Ali Demir; Ozan Sargin
2014-09-25T23:59:59.000Z
As an application of the polymer quantization scheme, in this work we investigate the one dimensional quantum mechanical tunneling phenomenon from the perspective of polymer representation of a non-relativistic point particle and derive the transmission and reflection coefficients. Since any tunneling phenomenon inevitably evokes a tunneling time we attempt an analytical calculation of tunneling times by defining an operator well suited in discrete spatial geometry. The results that we come up with hint at appearance of the Quantum Zeno Effect in polymer framework.
Lecture Notes in Quantum Mechanics
Doron Cohen
2013-08-27T23:59:59.000Z
These lecture notes cover undergraduate textbook topics (e.g. as in Sakurai), and also additional advanced topics at the same level of presentation. In particular: EPR and Bell; Basic postulates; The probability matrix; Measurement theory; Entanglement; Quantum computation; Wigner-Weyl formalism; The adiabatic picture; Berry phase; Linear response theory; Kubo formula; Modern approach to scattering theory with mesoscopic orientation; Theory of the resolvent and the Green function; Gauge and Galilei Symmetries; Motion in magnetic field; Quantum Hall effect; Quantization of the electromagnetic field; Fock space formalism.
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."
Anti-Zeno Effect for Quantum Transport in Disordered Systems
Keisuke Fujii; Katsuji Yamamoto
2010-10-21T23:59:59.000Z
We demonstrate that repeated measurements in disordered systems can induce quantum anti-Zeno effect under certain condition to enhance quantum transport. The enhancement of energy transfer is really exhibited with a simple model under repeated measurements. The optimal measurement interval for the anti-Zeno effect and the maximal efficiency of energy transfer are specified in terms of the relevant physical parameters. Since the environment acts as frequent measurements on the system, the decoherence-induced energy transfer, which has been discussed recently for photosynthetic complexes, may be interpreted in terms of the anti-Zeno effect. We further find an interesting phenomenon, where local decoherence or repeated measurements may even promote entanglement generation between the non-local sites.
Fractal sets of dual topological quantum numbers
Wellington da Cruz
2004-06-18T23:59:59.000Z
The universality classes of the quantum Hall transitions are considered in terms of fractal sets of dual topological quantum numbers filling factors, labelled by a fractal or Hausdorff dimension defined into the interval $1 < h < 2$ and associated with fractal curves. We show that our approach to the fractional quantum Hall effect-FQHE is free of any empirical formula and this characteristic appears as a crucial insight for our understanding of the FQHE. According to our formulation, the FQHE gets a fractal structure from the connection between the filling factors and the Hausdoff dimension of the quantum paths of particles termed fractons which obey a fractal distribution function associated with a fractal von Neumann entropy. This way, the quantum Hall transitions satisfy some properties related to the Farey sequences of rational numbers and so our theoretical description of the FQHE establishes a connection between physics, fractal geometry and number theory. The FQHE as a convenient physical system for a possible prove of the Riemann hypothesis is suggested.
Non-adiabatic effect on the quantum heat flux control
Chikako Uchiyama
2014-05-08T23:59:59.000Z
We provide a general formula of quantum transfer that includes the non-adiabatic effect under periodic environmental modulation by using full counting statistics in Hilbert-Schmidt space. Applying the formula to an anharmonic junction model that interacts with two bosonic environments within the Markovian approximation, we find that the quantum transfer is divided into the adiabatic (dynamical and geometrical phases) and non-adiabatic contributions. This extension shows the dependence of quantum transfer on the initial condition of the anharmonic junction just before the modulation, as well as the characteristic environmental parameters such as interaction strength and cut-off frequency of spectral density. We show that the non-adiabatic contribution represents the reminiscent effect of past modulation including the transition from the initial condition of the anharmonic junction to a steady state determined by the very beginning of the modulation. This enables us to tune the frequency range of modulation, whereby we can obtain the quantum flux corresponding to the geometrical phase by setting the initial condition of the anharmonic junction.
Nambu-Goldstone Effective Theory of Information at Quantum Criticality
Gia Dvali; Andre Franca; Cesar Gomez; Nico Wintergerst
2015-07-10T23:59:59.000Z
We establish a fundamental connection between quantum criticality of a many-body system, such as Bose-Einstein condensates, and its capacity of information-storage and processing. For deriving the effective theory of modes in the vicinity of the quantum critical point we develop a new method by mapping a Bose-Einstein condensate of $N$-particles onto a sigma model with a continuous global (pseudo)symmetry that mixes bosons of different momenta. The Bogolyubov modes of the condensate are mapped onto the Goldstone modes of the sigma model, which become gapless at the critical point. These gapless Goldstone modes are the quantum carriers of information and entropy. Analyzing their effective theory, we observe the information-processing properties strikingly similar to the ones predicted by the black hole portrait. The energy cost per qubit of information-storage vanishes in the large-$N$ limit and the total information-storage capacity increases with $N$ either exponentially or as a power law. The longevity of information-storage also increases with $N$, whereas the scrambling time in the over-critical regime is controlled by the Lyapunov exponent and scales logarithmically with $N$. This connection reveals that the origin of black hole information storage lies in the quantum criticality of the graviton Bose-gas, and that much simpler systems that can be manufactured in table-top experiments can exhibit very similar information-processing dynamics.
Relativistic Doppler effect in quantum communication
Asher Peres; Daniel R. Terno
2003-04-06T23:59:59.000Z
When an electromagnetic signal propagates in vacuo, a polarization detector cannot be rigorously perpendicular to the wave vector because of diffraction effects. The vacuum behaves as a noisy channel, even if the detectors are perfect. The ``noise'' can however be reduced and nearly cancelled by a relative motion of the observer toward the source. The standard definition of a reduced density matrix fails for photon polarization, because the transversality condition behaves like a superselection rule. We can however define an effective reduced density matrix which corresponds to a restricted class of positive operator-valued measures. There are no pure photon qubits, and no exactly orthogonal qubit states.
Vacuum state truncation via the quantum Zeno effect
Tae-Gon Noh
2012-08-22T23:59:59.000Z
In the context of quantum state engineering we analyze the effect of observation on nonlinear optical $n$-photon Fock state generation. We show that it is possible to truncate the vacuum component from an arbitrary photon number superposition without modifying its remaining parts. In the course of the full dynamical analysis of the effect of observation, it is also found that the Zeno and the anti-Zeno effects repeat periodically. We discuss the close relationship between vacuum state truncation and so-called "interaction-free" measurement.
Hall viscosity from elastic gauge fields in Dirac crystals
Alberto Cortijo; Yago Ferreirós; Karl Landsteiner; María A. H. Vozmediano
2015-06-16T23:59:59.000Z
The combination of Dirac physics and elasticity has been explored at length in graphene where the so--called "elastic gauge fields" have given rise to an entire new field of research and applications: Straintronics. The fact that these elastic fields couple to fermions as the electromagnetic field, implies that many electromagnetic responses will have elastic counterparts not explored before. In this work we will first show that the presence of elastic gauge fields will be the rule rather than the exception in most of the topologically non--trivial materials in two and three dimensions. In particular we will extract the elastic gauge fields associated to the recently observed Weyl semimetals, the "three dimensional graphene". As it is known, quantum electrodynamics suffers from the chiral anomaly whose consequences have been recently explored in matter systems. We will show that, associated to the physics of the anomalies, and as a counterpart of the Hall conductivity, elastic materials will have a Hall viscosity in two and three dimensions with a coefficient orders of magnitude bigger than the previously studied response. The magnitude and generality of the new effect will greatly improve the chances for the experimental observation of this topological, non dissipative response.
The Monty Hall Problem Richard D. Gill
Gill, Richard D.
the Monty Hall problem is often called the Monty Hall para- dox. The key to accepting and understanding
Nambu-Goldstone Effective Theory of Information at Quantum Criticality
Dvali, Gia; Gomez, Cesar; Wintergerst, Nico
2015-01-01T23:59:59.000Z
We establish a fundamental connection between quantum criticality of a many-body system, such as Bose-Einstein condensates, and its capacity of information-storage and processing. For deriving the effective theory of modes in the vicinity of the quantum critical point we develop a new method by mapping a Bose-Einstein condensate of $N$-particles onto a sigma model with a continuous global (pseudo)symmetry that mixes bosons of different momenta. The Bogolyubov modes of the condensate are mapped onto the Goldstone modes of the sigma model, which become gapless at the critical point. These gapless Goldstone modes are the quantum carriers of information and entropy. Analyzing their effective theory, we observe the information-processing properties strikingly similar to the ones predicted by the black hole portrait. The energy cost per qubit of information-storage vanishes in the large-$N$ limit and the total information-storage capacity increases with $N$ either exponentially or as a power law. The longevity of i...
Adding quantum effects to the semi-classical molecular dynamics simulations
Yang, Siyang
2011-01-01T23:59:59.000Z
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 trajecto...
Quantum effects with an X-ray free electron laser
C. D. Roberts; S. M. Schmidt; D. V. Vinnik
2002-06-03T23:59:59.000Z
A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an XFEL facility to expose intrinsically quantum effects in the process of QED vacuum decay via spontaneous pair production. A 9 TW-peak XFEL laser with photon energy 8.3 keV could be sufficient to initiate particle accumulation and the consequent formation of a plasma of spontaneously produced pairs. The evolution of the particle number in the plasma will exhibit non-Markovian aspects of the strong-field pair production process and the plasma's internal currents will generate an electric field whose interference with that of the laser leads to plasma oscillations.
Effect of quantum nuclear motion on hydrogen bonding
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
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.
Madami, M; Moriyama, T; Tanaka, K; Siracusano, G; Carpentieri, M; Finocchio, G; Tacchi, S; Ono, T; Carlotti, G
2015-01-01T23:59:59.000Z
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...
Particle decay processes, the quantum Zeno effect and the continuity of time
George Jaroszkiewicz; Jon Eakins
2006-10-24T23:59:59.000Z
Signal-state quantum mechanics is used to discuss quantum mechanical particle decay probabilities and the quantum Zeno effect. This approach avoids the assumption of continuous time, conserves total probability and requires neither non-Hermitian Hamiltonians nor the ad-hoc introduction of complex energies. The formalism is applied to single channel decays, the ammonium molecule, and neutral Kaon decay processes.
Hall provided that capacity exists after fulfilling fulltime student demand and that affiliates Cards are issued by the registrar's office, but are encoded for residential use by the Student Housing are shared with a suite mate. Kitchen and laundry facilities are located on each residential floor. All rooms
Housing services Zinfandel Hall
Ravikumar, B.
Housing services Zinfandel Hall (707) 664-2541 Fax: (707) 664-4158 e-mail: ssu.housing@sonoma.edu www.sonoma.edu/housing On-Campus Housing The Residential Community provides comfortable, convenient cam- pus housing for 3,000 single students. The Community is a unique mix of nontraditional resident
Residence Hall Fire Safety Information Department of Public Safety Residential Life & Housing #12;Part 1 ! Building Information Pursuant to New York City Fire Code and Local Law 10, this Fire Safety, as well as what to do in a fire emergency. Building Construction Residential buildings built before 1968
Effect of phase transition on quantum transport in group-IV two-dimensional U-shape device
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
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.
Quantum effective potential, electron transport and conformons in biopolymers
Rossen Dandoloff; Radha Balakrishnan
2005-05-29T23:59:59.000Z
In the Kirchhoff model of a biopolymer, conformation dynamics can be described in terms of solitary waves, for certain special cross-section asymmetries. Applying this to the problem of electron transport, we show that the quantum effective potential arising due to the bends and twists of the polymer enables us to formalize and quantify the concept of a {\\it conformon} that has been hypothesized in biology. Its connection to the soliton solution of the cubic nonlinear Schr\\"{o}dinger equation emerges in a natural fashion.
Semianalytical quantum model for graphene field-effect transistors
Pugnaghi, Claudio; Grassi, Roberto, E-mail: roberto.grassi@unibo.it; Gnudi, Antonio; Di Lecce, Valerio; Gnani, Elena; Reggiani, Susanna; Baccarani, Giorgio [ARCES and DEI, University of Bologna, Viale Risorgimento 2, 40136 Bologna (Italy)
2014-09-21T23:59:59.000Z
We develop a semianalytical model for monolayer graphene field-effect transistors in the ballistic limit. Two types of devices are considered: in the first device, the source and drain regions are doped by charge transfer with Schottky contacts, while, in the second device, the source and drain regions are doped electrostatically by a back gate. The model captures two important effects that influence the operation of both devices: (i) the finite density of states in the source and drain regions, which limits the number of states available for transport and can be responsible for negative output differential resistance effects, and (ii) quantum tunneling across the potential steps at the source-channel and drain-channel interfaces. By comparison with a self-consistent non-equilibrium Green's function solver, we show that our model provides very accurate results for both types of devices, in the bias region of quasi-saturation as well as in that of negative differential resistance.
Path Integral and Effective Hamiltonian in Loop Quantum Cosmology
Haiyun Huang; Yongge Ma; Li Qin
2011-06-27T23:59:59.000Z
We study the path integral formulation of Friedmann universe filled with a massless scalar field in loop quantum cosmology. All the isotropic models of $k=0,+1,-1$ are considered. To construct the path integrals in the timeless framework, a multiple group-averaging approach is proposed. Meanwhile, since the transition amplitude in the deparameterized framework can be expressed in terms of group-averaging, the path integrals can be formulated for both deparameterized and timeless frameworks. Their relation is clarified. It turns out that the effective Hamiltonian derived from the path integral in deparameterized framework is equivalent to the effective Hamiltonian constraint derived from the path integral in timeless framework, since they lead to same equations of motion. Moreover, the effective Hamiltonian constraints of above models derived in canonical theory are confirmed by the path integral formulation.
Quantum Hall Effect near the Charge Neutrality Point in a Two-Dimensional Electron-Hole System
Gusev, Guennady
. Gusev,1 E. B. Olshanetsky,1,2 Z. D. Kvon,2 N. N. Mikhailov,2 S. A. Dvoretsky,2 and J. C. Portal3,4,5 1 of Semiconductor Physics, Novosibirsk 630090, Russia 3 LNCMI-CNRS, UPR 3228, BP 166, 38042 Grenoble Cedex 9, France
On Quantum Coherence Effects in Photo and Solar Cells
Kimberly Chapin; Konstantin Dorfman; Anatoly Svidzinsky; Marlan Scully
2011-02-01T23:59:59.000Z
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).
Quantum noise effects with Kerr nonlinearity enhancement in coupled gain-loss waveguides
Bing He; Shu-Bin Yan; Jing Wang; Min Xiao
2015-05-26T23:59:59.000Z
It is generally difficult to study the dynamical properties of a quantum system with both inherent quantum noises and non-perturbative nonlinearity. Due to the possibly drastic intensity increase of an input coherent light in the gain-loss waveguide couplers with parity-time (PT) symmetry, the Kerr effect from a nonlinearity added into the systems can be greatly enhanced, and is expected to create the macroscopic entangled states of the output light fields with huge photon numbers. Meanwhile, the quantum noises also coexist with the amplification and dissipation of the light fields. Under the interplay between the quantum noises and nonlinearity, the quantum dynamical behaviors of the systems become rather complicated. However, the important quantum noise effects have been mostly neglected in the previous studies about nonlinear PT-symmetric systems. Here we present a solution to this non-perturbative quantum nonlinear problem, showing the real-time evolution of the system observables. The enhanced Kerr nonlinearity is found to give rise to a previously unknown decoherence effect that is irrelevant to the quantum noises, and imposes a limit on the emergence of macroscopic nonclassicality. In contrast to what happen in the linear systems, the quantum noises exert significant impact on the system dynamics, and can create the nonclassical light field states in conjunction with the enhanced Kerr nonlinearity. This first study on the noise involved quantum nonlinear dynamics of the coupled gain-loss waveguides can help to better understand the quantum noise effects in the broad nonlinear systems.
Ozturk, Salih Baris
2007-04-25T23:59:59.000Z
This thesis focuses on the development of a novel Direct Torque Control (DTC) scheme for permanent magnet (PM) synchronous motors (surface and interior types) in the constant torque region with the help of cost-effective ...
The Casimir effect: from quantum to critical fluctuations
Andrea Gambassi
2008-12-04T23:59:59.000Z
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.
TRINITY HALL ACCOUNTS FOR THE YEAR ENDED
Talbot, James P.
TRINITY HALL CAMBRIDGE ACCOUNTS FOR THE YEAR ENDED 30 June 2011 #12;TRINITY HALL Index Balance Sheet 19 Cash Flow Statement 20 - 32 Notes to the Accounts #12;TRINITY HALL Governing Body;Status Trinity Hall, or The Master, Fellows and Scholars of the College or Hall of the Holy Trinity
Cylindrical geometry hall thruster
Raitses, Yevgeny (Princeton, NJ); Fisch, Nathaniel J. (Princeton, NJ)
2002-01-01T23:59:59.000Z
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.
The Hall D Physics Program at JLab
Leckey, John P. [Indiana U.
2012-09-01T23:59:59.000Z
GlueX is one of the flagship experiments of the 12 GeV era at the Thomas Jefferson National Accelerator Facility (JLab). The energy of the electron accelerator at JLab is presently undergoing an upgrade from 6 GeV to 12 GeV and a 4th experimental hall (Hall D) is being added. The GlueX experimental apparatus consists of a tagged coherent bremsstrahlung photon beam incident on a liquid hydrogen target. The photoproduced mesons, which are created inside of a 2.2 T solenoid, will then pass through a pair of drift chambers and eventually deposit their energy into either of two calorimeters, depending on their respective angles. GlueX will attempt to map out the light meson spectrum and search for meson-gluon hybrids to better understand the confinement of quarks and gluons in quantum chromodynamics (QCD). There is little data on the photoproduction of light mesons and the GlueX experiment will exceed the current photoproduction data by several orders of magnitude in the first year alone. Photoproduction is specifically well suited to search for meson-gluon hybrids because in the flux tube model the production cross-sections are higher for meson-gluon hybrids from photons, with the spins of the virtual quark-antiquark pair aligned, than from other sources such as pions, with the spins of the quark-antiquark pair anti-aligned. There are also other Hall D experiments proposed to look for physics beyond the Standard Model by studying Eta rare or forbidden decay channels such as eta to two neutral pions. The 12 GeV upgrade of the JLab accelerator and the complete physics program of Hall D will be presented.
Bing Concert Hall, Under Construction
Prinz, Friedrich B.
Freidenrich Center, Under Construction Terman Engineering Center, Demolition Frost Amphitheater Ford Plaza Hall Cowell Houses Schwab Residential Center Lyman Graduate Residences Sterling Quad Mirrielees Pearce
Town Hall with Secretary Moniz
Broader source: Energy.gov [DOE]
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.
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.
Rhodes Hall Ross Heart Hospital
Howat, Ian M.
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
Can One Trust Quantum Simulators?
Philipp Hauke; Fernando M. Cucchietti; Luca Tagliacozzo; Ivan Deutsch; Maciej Lewenstein
2012-07-26T23:59:59.000Z
Various fundamental phenomena of strongly-correlated quantum systems such as high-$T_c$ superconductivity, the fractional quantum-Hall effect, and quark confinement are still awaiting a universally accepted explanation. The main obstacle is the computational complexity of solving even the most simplified theoretical models that are designed to capture the relevant quantum correlations of the many-body system of interest. In his seminal 1982 paper [Int. J. Theor. Phys. 21, 467], Richard Feynman suggested that such models might be solved by "simulation" with a new type of computer whose constituent parts are effectively governed by a desired quantum many-body dynamics. Measurements on this engineered machine, now known as a "quantum simulator," would reveal some unknown or difficult to compute properties of a model of interest. We argue that a useful quantum simulator must satisfy four conditions: relevance, controllability, reliability, and efficiency. We review the current state of the art of digital and analog quantum simulators. Whereas so far the majority of the focus, both theoretically and experimentally, has been on controllability of relevant models, we emphasize here the need for a careful analysis of reliability and efficiency in the presence of imperfections. We discuss how disorder and noise can impact these conditions, and illustrate our concerns with novel numerical simulations of a paradigmatic example: a disordered quantum spin chain governed by the Ising model in a transverse magnetic field. We find that disorder can decrease the reliability of an analog quantum simulator of this model, although large errors in local observables are introduced only for strong levels of disorder. We conclude that the answer to the question "Can we trust quantum simulators?" is... to some extent.
Cosmological fluctuations: Comparing Quantum and Classical Statistical and Stringy Effects
de Alwis, S P
2015-01-01T23:59:59.000Z
The theory of cosmological fluctuations assumes that the pre-inflationary state of the universe was the quantum vacuum of a scalar field(s) coupled to gravity. The observed cosmic microwave background fluctuations are then interpreted as quantum fluctuations. Here we consider alternate interpretations of the classic calculations of scalar and tensor power spectra by replacing the quantum vacuum with a classical statistical distribution, and suggest a way of distinguishing the quantum from the classical alternatives. The possibility that the latter is governed by a fundamental length scale as in string theory is also explored.
A quantitative account of quantum effects in liquid water. |...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
report quantum statistical mechanical simulations of liquid water with the TTM2.1-F flexible, polarizable interaction potential for water. The potential is the first...
Quantum fluctuations and isotope effects in ab initio descriptions of 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
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.
Acceleration of positrons by a relativistic electron beam 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
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.
Le Roy, Robert J.
February 1998 Comparisons of classical and quantum Monte Carlo simulation of SF6 Ar n and SF6 Ne n clusters are used to examine whether certain novel types of behavior seen in classical simulations of SF6 Ar n and SF6 Kr n persist when quantum effects are taken into account. For mixed clusters formed
Progress Toward Observing Quantum Effects in an Optomechanical System in Cryogenics
Harris, Jack
, placed at 400 mK inside a 3 He fridge. The major goals of this research are: laser cooling the 261 kAbstract Progress Toward Observing Quantum Effects in an Optomechanical System in Cryogenics Cheng Yang 2011 Quantum optomechanical systems use radiation pressure of light to couple the optical field
Quantum size effects and transport phenomena in PbSe quantum wells and PbSe/EuS superlattices
Rogacheva, E. I.; Nashchekina, O. N.; Ol'khovskaya, S. I.; Sipatov, A. Yu. [National technical university Kharkov polytechnic institute, 21 Frunze St., Kharkov, 61002 (Ukraine); Dresselhaus, M. S. [Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge MA 02139 (United States)
2013-12-04T23:59:59.000Z
It is established that the room-temperature dependences of transport properties on the total thickness of PbSe layers d in PbSe/EuS superlattices exhibit an oscillatory behavior. It is shown that the oscillation period ?d practically coincides with the period of the thickness oscillations observed earlier in single PbSe/EuS quantum well. The non-monotonic character of these dependences is attributed to quantum size effects. The theoretically estimated and experimentally determined ?d values are in good agreement.
CONFERENCES | EVENTS | FINE DINING TRINITY HALL
Lasenby, Joan
CONFERENCES | EVENTS | FINE DINING #12;32 WELCOME WELCOME TO TRINITY HALL CONFERENCE AND EVENTS "If and point the way to the gardens of Trinity Hall. "HENRY JAMES 1878 Trinity Hall is the fifth oldest college from the hustle and bustle of the City, Trinity Hall has a quiet, peaceful air making it perfect
Quantum coherence effects in quasidegenerate two-level atomic systems
Dong Yabin; Wang Haihong; Gao Jiangrui; Zhang Junxiang [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)
2006-12-15T23:59:59.000Z
The wealth of quantum coherence effects depending on the orientation of external magnetic field, the polarization of coupling and probe lights, and the Rabi frequency of the coupling beam are studied in transition F{sub e}=2{r_reversible}F{sub g}=3 of Cs D{sub 2} line. The split of electromagnetically induced transparency (EIT) resonances on two or three resonances determined by the different combination of the polarization of interaction lights and the direction of applied magnetic fields is obtained. The shifting and widening of the EIT resonances with the strength of the magnetic field (i.e., Zeeman splitting in the upper and lower levels) and Rabi frequency of the coupling beam increasing are also discussed. It may develop into the potential application for tunable multichannel optical information storage. On the other hand, an explanation of observed asymmetry of spectra by laser frequency offset from the optical resonance is given with theoretical calculation, which is in good agreement with the experimental results.
Quantum effects in many-body gravitating systems
V. A. Golovko
2015-04-07T23:59:59.000Z
A hierarchy of equations for equilibrium reduced density matrices obtained earlier is used to consider systems of spinless bosons bound by forces of gravity alone. The systems are assumed to be at absolute zero of temperature under conditions of Bose condensation. In this case, a peculiar interplay of quantum effects and of very weak gravitational interaction between microparticles occurs. As a result, there can form spatially-bounded equilibrium structures macroscopic in size, both immobile and rotating. The size of a structure is inversely related to the number of particles in the structure. When the number of particles is relatively small the size can be enormous, whereas if this numbder equals Avogadro's number the radius of the structure is about 30 cm in the case that the structure consists of hydrogen atoms. The rotating objects have the form of rings and exhibit superfluidity. An atmosphere that can be captured by tiny celestial bodies from the ambient medium is considered too. The thickness of the atmosphere decreases as its mass increases. If short-range intermolecular forces are taken into account, the results obtained hold for excited states whose lifetime can however be very long. The results of the paper can be utilized for explaining the first stage of formation of celestial bodies from interstellar and even intergalactic gases.
Quantum effects in many-body gravitating systems
Golovko, V A
2015-01-01T23:59:59.000Z
A hierarchy of equations for equilibrium reduced density matrices obtained earlier is used to consider systems of spinless bosons bound by forces of gravity alone. The systems are assumed to be at absolute zero of temperature under conditions of Bose condensation. In this case, a peculiar interplay of quantum effects and of very weak gravitational interaction between microparticles occurs. As a result, there can form spatially-bounded equilibrium structures macroscopic in size, both immobile and rotating. The size of a structure is inversely related to the number of particles in the structure. When the number of particles is relatively small the size can be enormous, whereas if this numbder equals Avogadro's number the radius of the structure is about 30 cm in the case that the structure consists of hydrogen atoms. The rotating objects have the form of rings and exhibit superfluidity. An atmosphere that can be captured by tiny celestial bodies from the ambient medium is considered too. The thickness of the at...
Melnik, Roderick
Coupled electromechanical effects in wurtzite quantum dots with wetting layers in gate controlled quantifies the electromechanical effects on the band structure of wurtzite quantum dots. c Systematic study on the band structure calculations of wurtzite AlN/GaN quantum dots with wetting layers (WLs). Based
Resonances of the confined hydrogeno¨id ion and the Dicke effect in non-relativistic quantum describes a hydrogeno¨id ion confined by its center of mass, and is used in theoretical physics to explain
A quantum-geometrical description of fracton statistics
Wellington da Cruz
2003-05-26T23:59:59.000Z
We consider the fractal characteristic of the quantum mechanical paths and we obtain for any universal class of fractons labeled by the Hausdorff dimension defined within the interval 1$ $$ < $$ $$h$$ $$ <$$ $$ 2$, a fractal distribution function associated with a fractal von Neumann entropy. Fractons are charge-flux systems defined in two-dimensional multiply connected space and they carry rational or irrational values of spin. This formulation can be considered in the context of the fractional quantum Hall effect-FQHE and number theory.
Broader source: Energy.gov [DOE]
Secretary Steven Chu hosted an online town hall to discuss the clean energy and innovation agenda President Obama laid out in his 2011 State of the Union address. (January 26, 2011)
Effect of noise on time-dependent quantum chaos
Ott, E.; Antonsen T.M. Jr.; Hanson, J.D.
1984-12-03T23:59:59.000Z
The dynamics of a time-dependent quantum system can be qualitatively different from that of its classical counterpart when the latter is chaotic. It is shown that small noise can strongly alter this situation.
Optimization of Cylindrical Hall Thrusters
Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fi
2007-07-24T23:59:59.000Z
The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation. __________________________________________________
Optimization of Cylindrical Hall Thrusters
Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fisch
2007-11-27T23:59:59.000Z
The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.
Quantum-mechanical description of Lense-Thirring effect for relativistic scalar particles
Alexander J. Silenko
2014-08-10T23:59:59.000Z
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.
Shepelyansky, Dima
of Quantum Chaos and Imperfection Effects Pil Hun Song1 and Dima L. Shepelyansky2 1 Max-Planck-Institut fÃ¼r model in the regime of quantum chaos. It is shown that there are two types of physical characteristics of imperfection effects we analyze in this paper their influence on a quantum compu- tation of quantum chaos
Eslami, L., E-mail: Leslami@iust.ac.ir; Faizabadi, E. [School of Physics, Iran University of Science and Technology, Tehran 16846 (Iran, Islamic Republic of)
2014-05-28T23:59:59.000Z
The effect of magnetic contacts on spin-dependent electron transport and spin-accumulation in a quantum ring, which is threaded by a magnetic flux, is studied. The quantum ring is made up of four quantum dots, where two of them possess magnetic structure and other ones are subjected to the Rashba spin-orbit coupling. The magnetic quantum dots, referred to as magnetic quantum contacts, are connected to two external leads. Two different configurations of magnetic moments of the quantum contacts are considered; the parallel and the anti-parallel ones. When the magnetic moments are parallel, the degeneracy between the transmission coefficients of spin-up and spin-down electrons is lifted and the system can be adjusted to operate as a spin-filter. In addition, the accumulation of spin-up and spin-down electrons in non-magnetic quantum dots are different in the case of parallel magnetic moments. When the intra-dot Coulomb interaction is taken into account, we find that the electron interactions participate in separation between the accumulations of electrons with different spin directions in non-magnetic quantum dots. Furthermore, the spin-accumulation in non-magnetic quantum dots can be tuned in the both parallel and anti-parallel magnetic moments by adjusting the Rashba spin-orbit strength and the magnetic flux. Thus, the quantum ring with magnetic quantum contacts could be utilized to create tunable local magnetic moments which can be used in designing optimized nanodevices.
Dowling, Jonathan P.
to the loss of photons caused by the inter- action between the fiber and the electromagnetic field. By frequently monitoring the presence of the photon through a quantum non-demolition (QND) measurement), and the processing is accomplished by sending the photon through a system of linear optical elements and using
Effects of quantum space time foam in the neutrino sector
H. V. Klapdor-Kleingrothaus; H. Päs; U. Sarkar
2000-07-05T23:59:59.000Z
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.
The effect of Coulomb interactions on thermoelectric properties of quantum dots
Zimbovskaya, Natalya A. [Department of Physics and Electronics, University of Puerto Rico-Humacao, CUH Station, Humacao, Puerto Rico 00791, USA and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Ruco 00931 (United States)] [Department of Physics and Electronics, University of Puerto Rico-Humacao, CUH Station, Humacao, Puerto Rico 00791, USA and Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Ruco 00931 (United States)
2014-03-14T23:59:59.000Z
Thermoelectric effects in a quantum dot coupled to the source and drain charge reservoirs are explored using a nonequilibrium Green's functions formalism beyond the Hartree-Fock approximation. Thermal transport is analyzed within a linear response regime. A transition from Coulomb blockade regime to Kondo regime in thermoelectric transport through a single-level quantum dot is traced using unified approximations for the relevant Green's functions.
Tunneling of the 3rd Kind: A Test of the Effective Non-locality of Quantum Field Theory
Simon A. Gardiner; Holger Gies; Joerg Jaeckel; Chris J. Wallace
2013-04-09T23:59:59.000Z
Integrating out virtual quantum fluctuations in an originally local quantum field theory results in an effective theory which is non-local. In this Letter we argue that tunneling of the 3rd kind - where particles traverse a barrier by splitting into a pair of virtual particles which recombine only after a finite distance - provides a direct test of this non-locality. We sketch a quantum-optical setup to test this effect, and investigate observable effects in a simple toy model.
Physics program in Hall A at CEBAF
Saha, A.
1990-01-01T23:59:59.000Z
We present here the physics program planned for Hall A at CEBAF. It encompass exclusive as well as inclusive electromagnetic measurements requiring both high precision and accuracy. The program includes measurements of the elementary form factors of the nucleon, systematic studies of the few nucleon systems (d, {sup 3,4}He), high momentum structure of nuclei, their structure at high Q{sup 2} to look for hadronization and quark effects, spin response of nuclei via ({rvec e}, e{prime}{rvec p}) reactions and the study of nuclear pion fields.
Testing quantum-like models of judgment for question order effect
Thomas Boyer-Kassem; Sébastien Duchêne; Éric Guerci
2015-08-25T23:59:59.000Z
Lately, so-called "quantum" models, based on parts of the mathematics of quantum mechanics, have been developed in decision theory and cognitive sciences to account for seemingly irrational or paradoxical human judgments. We consider here some such quantum-like models that address question order effects, i.e. cases in which given answers depend on the order of presentation of the questions. Models of various dimensionalities could be used, can the simplest ones be empirically adequate? From the quantum law of reciprocity, we derive new empirical predictions that we call the Grand Reciprocity equations, that must be satisfied by several existing quantum-like models, in their non-degenerate versions. Using substantial existing data sets, we show that these non-degenerate versions fail the GR test in most cases, which means that, if quantum-like models of the kind considered here are to work, it can only be in their degenerate versions. However, we suggest that the route of degenerate models is not necessarily an easy one, and we argue for more research on the empirical adequacy of degenerate quantum-like models in general.
Hall viscosity from elastic gauge fields in Dirac crystals
Cortijo, Alberto; Landsteiner, Karl; Vozmediano, María A H
2015-01-01T23:59:59.000Z
The combination of Dirac physics and elasticity has been explored at length in graphene where the so--called "elastic gauge fields" have given rise to an entire new field of research and applications: Straintronics. The fact that these elastic fields couple to fermions as the electromagnetic field, implies that many electromagnetic responses will have elastic counterparts not explored before. In this work we will first show that the presence of elastic gauge fields will be the rule rather than the exception in most of the topologically non--trivial materials in two and three dimensions. In particular we will extract the elastic gauge fields associated to the recently observed Weyl semimetals, the "three dimensional graphene". As it is known, quantum electrodynamics suffers from the chiral anomaly whose consequences have been recently explored in matter systems. We will show that, associated to the physics of the anomalies, and as a counterpart of the Hall conductivity, elastic materials will have a Hall visco...
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
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.
THalumni.net Trinity Hall's online community
Lasenby, Joan
THalumni.net Trinity Hall's online community Joining THalumni.net allows members to: · Check or location and send a private message to other Trinity Hall members. · Join the careers directory if you or loca- tion and send Trinity Hall members a private message. · Book and pay for events online and see
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), 2002; Level:5 TablesExports(Journal Article) | SciTech Connect Journal Article: X-rayContract Documents PPPL TheA PhysicsdifferencesEventsExperimental Hall C AnHall
Nanoconstriction-based spin-Hall nano-oscillator
Demidov, V. E., E-mail: demidov@uni-muenster.de [Department of Physics and Center for Nonlinear Science, University of Muenster, Corrensstr. 2-4, 48149 Muenster (Germany); Urazhdin, S.; Zholud, A. [Department of Physics, Emory University, 400 Dowman Dr., Atlanta, Georgia 30322 (United States); Sadovnikov, A. V. [Department of Physics and Center for Nonlinear Science, University of Muenster, Corrensstr. 2-4, 48149 Muenster (Germany); Saratov State University, 83 Astrakhanskaya str., Saratov 410012 (Russian Federation); Demokritov, S. O. [Department of Physics and Center for Nonlinear Science, University of Muenster, Corrensstr. 2-4, 48149 Muenster (Germany); Institute of Metal Physics, Ural Division of RAS, Yekaterinburg 620041 (Russian Federation)
2014-10-27T23:59:59.000Z
We experimentally demonstrate magnetic nano-oscillators driven by pure spin current produced by the spin Hall effect in a bow tie-shaped nanoconstriction. These devices exhibit single-mode auto-oscillation and generate highly-coherent electronic microwave signals with a significant power and the spectral linewidth as low as 6.2?MHz at room temperature. The proposed simple and flexible device geometry is amenable to straightforward implementation of advanced spintronic structures such as chains of mutually coupled spin-Hall nano-oscillators.
Holonomic Quantum Computing Based on the Stark Effect
Bernevig, B A
2004-01-01T23:59:59.000Z
We propose a spin manipulation technique based entirely on electric fields applied to acceptor states in $p$-type semiconductors with spin-orbit coupling. While interesting in its own right, the technique can also be used to implement fault-resilient holonomic quantum computing. We explicitly compute adiabatic transformation matrix (holonomy) of the degenerate states and comment on the feasibility of the scheme as an experimental technique.
Holonomic Quantum Computing Based on the Stark Effect
B. A. Bernevig; S. C. Zhang
2004-02-23T23:59:59.000Z
We propose a spin manipulation technique based entirely on electric fields applied to acceptor states in $p$-type semiconductors with spin-orbit coupling. While interesting in its own right, the technique can also be used to implement fault-resilient holonomic quantum computing. We explicitly compute adiabatic transformation matrix (holonomy) of the degenerate states and comment on the feasibility of the scheme as an experimental technique.
A molecular dynamics study of nuclear quantum effect on the diffusion of hydrogen in condensed phase
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
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.
Generalized decoding, effective channels, and simplified security proofs in quantum key distribution
Renes, Joseph M. [IAKS Prof. Beth, Arbeitsgruppe Quantum Computing, Universitaet Karlsruhe, Am Fasanengarten 5, D-76131 Karlsruhe (Germany); Quantum Information Theory Group, Institut fuer Theoretische Physik I, and Max-Planck-Forschungsgruppe, Institut fuer Optik, Information und Photonik, Universitaet Erlangen-Nuernberg, Staudtstrasse 7, D-91058 Erlangen (Germany); Grassl, Markus [IAKS Prof. Beth, Arbeitsgruppe Quantum Computing, Universitaet Karlsruhe, Am Fasanengarten 5, D-76131 Karlsruhe (Germany)
2006-08-15T23:59:59.000Z
Prepare and measure quantum key distribution protocols can be decomposed into two basic steps: delivery of the signals over a quantum channel and distillation of a secret key from the signal and measurement records by classical processing and public communication. Here we formalize the distillation process for a general protocol in a purely quantum-mechanical framework and demonstrate that it can be viewed as creating an 'effective' quantum channel between the legitimate users Alice and Bob. The process of secret key generation can then be viewed as entanglement distribution using this channel, which enables application of entanglement-based security proofs to essentially any prepare and measure protocol. To ensure secrecy of the key, Alice and Bob must be able to estimate the channel noise from errors in the key, and we further show how symmetries of the distillation process simplify this task. Applying this method, we prove the security of several key distribution protocols based on equiangular spherical codes.
Minnesota, University of
Ctr, ARSF-Agricultural Research Support Facility, CH-Centennial Hall, DH-Dowell Hall, DA-Dowell Hall
Anh Tuan, Duong; Shin, Yooleemi; Viet Cuong, Tran; Cho, Sunglae, E-mail: slcho@ulsan.ac.kr [Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Phan, The-Long [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)
2014-05-07T23:59:59.000Z
The Fe{sub 1?x}Ga{sub x} thin films (x?=?0.4, 0.5) have been grown on GaSb(100) substrate using molecular beam epitaxy. An epitaxial film with bcc ?-Fe crystal structure (A2) is observed in Fe{sub 0.6}Ga{sub 0.4} film, while an impure Fe{sub 3}Ga phase with DO{sub 3} structure is appeared in Fe{sub 0.5}Ga{sub 0.5} film. The saturated magnetizations at room temperature are observed to be 570?emu/cm{sup 3} and 180?emu/cm{sup 3} and the coercivities to be 170 and 364?Oe for Fe{sub 0.6}Ga{sub 0.4} and Fe{sub 0.5}Ga{sub 0.5}, respectively. A hysteresis trend in Hall resistance vs. magnetic field is observed for Fe{sub 0.5}Ga{sub 0.5} film. However, there is a weak hysteresis noticed in Fe{sub 0.4}Ga{sub 0.6} thin film.
Bing Concert Hall, Under Construction
Straight, Aaron
a Tresidder Union Dinkelspiel AuditoriumFaculty Club Kingscote Gardens Braun Music Center The Knoll Bechtel Meyer Library Fire Truck Hse. Clock Tower Owen Bolivar House Haas Center Galvez Modular Bookstore Crothers Memorial Encina Commons Encina HallBing Wing Lou Henry Hoover Bldg.Hoover Tower Cummings Art Art
Bing Concert Hall, Under Construction
Prinz, Friedrich B.
BioE/ChemE Building Bing Concert Hall, Under Construction Arrillaga Family Dining Commons West Campus Recreation Center, Under Construction BioE/ChemE Building, Under Construction Terman Engineering Moore Materials Rsrch. Durand David Packard Elect. Eng. Paul G. Allen Building Roble Pool Roble Modulars
William James Granville Stanley Hall
Maxwell, Bruce D.
William James Harvard Granville Stanley Hall Johns Hopkins James Rowland Angell Chicago Morton Leon Festinger U. of Iowa Stanley Schacther U. Of Michigan Richard Nisbett Columbia Timothy D. Wilson U. of Michigan G. Daniel Lassiter U. of Virginia Ian Handley Ohio University Max Frederick Meyer U. Of Missouri
ANNUAL FIRE SAFETY RESIDENCE HALLS
Fernandez, Eduardo
1 2013 ANNUAL FIRE SAFETY REPORT FOR RESIDENCE HALLS As Required by the Higher Education Opportunity Act (HEOA) #12;2 INTRODUCTION Contents of this annual fire safety report reflect the requirements outlined in the HEOA, which are included in Florida Atlantic University's (FAU) campus fire safety program
Anyonic statistics and large horizon diffeomorphisms for Loop Quantum Gravity Black Holes
Andreas G. A. Pithis; Hans-Christian Ruiz Euler
2015-03-24T23:59:59.000Z
We investigate the role played by large diffeomorphisms of quantum Isolated Horizons for the statistics of LQG Black Holes by means of their relation to the braid group. To this aim the symmetries of Chern-Simons theory are recapitulated with particular regard to the aforementioned type of diffeomorphisms. For the punctured spherical horizon, these are elements of the mapping class group of $S^2$, which is almost isomorphic to a corresponding braid group on this particular manifold. The mutual exchange of quantum entities in two dimensions is achieved by the braid group, rendering the statistics anyonic. With this we argue that the quantum Isolated Horizon model of LQG based on $SU(2)_k$-Chern-Simons theory explicitly exhibits non-abelian anyonic statistics. In this way a connection to the theory behind the fractional quantum Hall effect and that of topological quantum computation is established, where non-abelian anyons play a significant role.
Effectiveness of classical spin simulations for describing NMR relaxation of quantum spins
Tarek A. Elsayed; Boris V. Fine
2014-09-29T23:59:59.000Z
We investigate the limits of effectiveness of classical spin simulations for predicting free induction decays (FIDs) measured by solid-state nuclear magnetic resonance (NMR) on systems of quantum nuclear spins. The specific limits considered are associated with the range of interaction, the size of individual quantum spins and the long-time behavior of the FID signals. We compare FIDs measured or computed for lattices of quantum spins (mainly spins 1/2) with the FIDs computed for the corresponding lattices of classical spins. Several cases of excellent quantitative agreement between quantum and classical FIDs are reported along with the cases of gradually decreasing quality of the agreement. We formulate semi-empirical criteria defining the situations, when classical simulations are expected to accurately reproduce quantum FIDs. Our findings indicate that classical simulations may be a quantitatively accurate tool of first principles calculations for a broad class of macroscopic systems, where individual quantum microscopic degrees of freedom are far from the classical limit.
Iye, Yasuhiro
by around Coulomb (resonant) peaks obeying the Breit-Wigner law. On the other hand, there appeared-phase Coulomb peaks" in quantum dots. KEYWORDS: quantum dot, Fano effect, phase shift, AB effect 1. Introduction of the phase shift just at the Coulomb peaks. This was soon turned out to be a kind of artifact due to the two
Vanderbilt, David
Effects of linear and nonlinear piezoelectricity on the electronic properties of InAs/GaAs quantum linear piezoelectric ef- fect into account and demonstrating important electronic consequences of the piezoelectric effect on electronic and optical properties of quantum dots and find that the quadratic and linear
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Mu Benrong; Peng Wang; Haitang Yang
2014-08-21T23:59:59.000Z
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance in quantum gravity effective models is a key for a black hole to have the remnant left in the evaporation.
Quantum effects in spontaneous emission by a relativistic, undulating electron beam
G. R. M. Robb; R. Bonifacio
2011-10-27T23:59:59.000Z
Current models of the effect of spontaneous emission on the electron beam dynamics neglect the discreteness of electron recoil associated with photon emission. We present a novel, one-dimensional model of the effect of spontaneous emission on the electron beam dynamics in an undulator both in the classical regime where discrete electron recoil is negligible, and the quantum regime where it is significant. It is shown that in the classical regime, continuous decrease of the average electron energy and diffusive growth of the electron energy spread occurs, in agreement with previous classical models. In the quantum regime, it is shown that the evolution of the electron momentum distribution occurs as discrete momentum groups according to a Poisson distribution. The narrow momentum features of the quantum regime may be useful for generation of coherent radiation, which relies on electron beams having sufficiently narrow momentum/energy distributions.
Quantum Gravity effect on neutrino oscillations in a strong gravitational field
Jonathan Miller; Roman Pasechnik
2014-11-14T23:59:59.000Z
In the framework of quantum field theory, a graviton interacts locally with a quantum state having definite mass, i.e. the gravitational mass eigenstate, while a weak boson interacts with a state having definite flavor, i.e. the flavor eigenstate. An interaction of a neutrino with an energetic graviton may trigger the collapse of the neutrino to a definite mass eigenstate with probability expressed in terms of PMNS mixing matrix elements. Thus, gravitons would induce quantum decoherence of a coherent neutrino flavor state similarly to how weak bosons induce quantum decoherence of a neutrino in a definite mass state. We demonstrate that such an essentially quantum gravity effect may have strong consequences for neutrino oscillation phenomena in astrophysics due to relatively large scattering cross sections of relativistic neutrinos undergoing large-angle radiation of energetic gravitons in gravitational field of a classical massive source (i.e. the quasi-classical case of gravitational Bethe-Heitler scattering). This graviton-induced {\\em decoherence} is compared to {\\em decoherence} due to propagation in the presence of the Earth matter effect. Based on this study, we propose a new technique for the indirect detection of energetic gravitons by measuring the flavor composition of astrophysical neutrinos.
Diederik Aerts; Massimiliano Sassoli de Bianchi
2015-08-15T23:59:59.000Z
A general tension-reduction (GTR) model was recently considered to derive quantum probabilities as (universal) averages over all possible forms of non-uniform fluctuations, and explain their considerable success in describing experimental situations also outside of the domain of physics, for instance in the ambit of quantum models of cognition and decision. Yet, this result also highlighted the possibility of observing violations of the predictions of the Born rule, in those situations where the averaging would not be large enough, or would be altered because of the combination of multiple measurements. In this article we show that this is indeed the case in typical psychological measurements exhibiting question order effects, by showing that their statistics of outcomes are inherently non-Hilbertian, and require the larger framework of the GTR-model to receive an exact mathematical description. We also consider another unsolved problem of quantum cognition: response replicability. It is has been observed that when question order effects and response replicability occur together, the situation cannot be handled anymore by quantum theory. However, we show that it can be easily and naturally described in the GTR-model. Based on these findings, we motivate the adoption in cognitive science of a hidden-measurements interpretation of the quantum formalism, and of its GTR-model generalization, as the natural interpretational framework explaining the data of psychological measurements on conceptual entities.
Non-singular bounce scenarios in loop quantum cosmology and the effective field description
Cai, Yi-Fu [Department of Physics, McGill University, Rue University, Montréal, QC H3A 2T8 (Canada); Wilson-Ewing, Edward, E-mail: yifucai@physics.mcgill.ca, E-mail: wilson-ewing@phys.lsu.edu [Department of Physics and Astronomy, Louisiana State University, Tower Drive, Baton Rouge, 70803 (United States)
2014-03-01T23:59:59.000Z
A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a non-standard kinetic term such that at high energy densities the field evolves into a ghost condensate and causes a non-singular bounce. During the bouncing phase, the perturbations can be stabilized by introducing a Horndeski operator. Taking the matter content to be a dust field and an ekpyrotic scalar field, we compare the dynamics in loop quantum cosmology and in a non-singular bouncing effective field model with a non-standard kinetic term at both the background and perturbative levels. We find that these two settings share many important properties, including the result that they both generate scale-invariant scalar perturbations. This shows that some quantum gravity effects of the very early universe may be mimicked by effective field models.
Effects of geometry and impurities on quantum rings in magnetic fields RID D-3014-2009
Aichinger, M.; Chin, Siu A.; Krotscheck, E.; Rasanen, E.
2006-01-01T23:59:59.000Z
We investigate the effects of impurities and changing ring geometry on the energetics of quantum rings under different magnetic field strengths. We show that as the magnetic field and/or the electron number are/is increased, both the quasiperiodic...
Hammes-Schiffer, Sharon
Multiconfigurational nuclear-electronic orbital approach: Incorporation of nuclear quantum effects 26 March 2002; accepted 30 May 2002 The nuclear-electronic orbital NEO method for the calculation of mixed nuclear-electronic wave functions is presented. Both electronic and nuclear molecular orbitals
Quantum Field Effects in Stationary Electron Spin Resonance Spectroscopy
Dmitri Yerchuck; Vyacheslav Stelmakh; Yauhen Yerchak; Alla Dovlatova
2015-01-28T23:59:59.000Z
It is proved on the example of electron spin resonance (ESR) studies of anthracites, that by strong electron-photon and electron-phonon interactions the formation of the coherent system of the resonance phonons takes place. The acoustic quantum Rabi oscillations were observed for the first time in ESR-spectroscopy. Its Rabi frequency value on the first damping stage was found to be equal 920.6 kHz, being to be independent on the microwave power level in the range 20 - 6 dB [0 dB corresponds to 100 mW]. By the subsequent increase of the microwave power the stepwise transition to the phenomenon of nonlinear quantum Rabi oscillations, characterised by splitting of the oscillation group of lines into two subgroups with doubling of the total lines' number takes place. Linewidth of an individual oscillation line becomes approximately the twofold narrower, being to be equal the only to $0.004 \\pm 0.001$ G. Along with the absorption process of EM-field energy the emission process was observed. It was found, that the emission process is the realization of the acoustic spin resonance, the source of acoustic wave power in which is the system of resonance phonons, accumulated in the samples by the registration with AFC. It has been found, that the lifetime of coherent state of a collective subsystem of resonance phonons in anthracites is very long and even by room temperature it is evaluated by the value exceeding 4.6 minutes. The model of new kinds of instantons was proposed. They are considered to be similar in the mathematical structure to Su-Schrieffer-Heeger solitons with "propagation" direction along time $t$-axis instead of space $z$-axis. The proof, that the superconductivity state in the anthracite samples studied is produced at the room temperature in ESR conditions in the accordance with the theory of the quantised acoustic field, has experimentally been obtained.
Gennady P. Berman; Fausto Borgonovi; Diego A. R. Dalvit
2008-01-29T23:59:59.000Z
We review our results on a mathematical dynamical theory for observables for open many-body quantum nonlinear bosonic systems for a very general class of Hamiltonians. We show that non-quadratic (nonlinear) terms in a Hamiltonian provide a singular "quantum" perturbation for observables in some "mesoscopic" region of parameters. In particular, quantum effects result in secular terms in the dynamical evolution, that grow in time. We argue that even for open quantum nonlinear systems in the deep quasi-classical region, these quantum effects can survive after decoherence and relaxation processes take place. We demonstrate that these quantum effects in open quantum systems can be observed, for example, in the frequency Fourier spectrum of the dynamical observables, or in the corresponding spectral density of noise. Estimates are presented for Bose-Einstein condensates, low temperature mechanical resonators, and nonlinear optical systems prepared in large amplitude coherent states. In particular, we show that for Bose-Einstein condensate systems the characteristic time of deviation of quantum dynamics for observables from the corresponding classical dynamics coincides with the characteristic time-scale of the well-known quantum nonlinear effect of phase diffusion.
Quantum statistics effect in Schwinger pair production in short laser pulses
Florian Hebenstreit; Reinhard Alkofer; Gerald V. Dunne; Holger Gies
2009-10-23T23:59:59.000Z
We investigate non-perturbative pair production from vacuum (the Schwinger effect) in the focal region of two counter-propagating, ultra-short laser pulses with sub-cycle structure. We use the quantum kinetic formulation to calculate the momentum spectrum of created particles and show the extreme sensitivity to the laser frequency $\\omega$, the pulse length $\\tau$ and the carrier-envelope absolute phase $\\phi$. We apply this formalism to both fermions and bosons to illustrate the influence of quantum statistics in this type of electric background field.
Probing Hawking and Unruh effects and quantum field theory in curved space by geometric invariants
Antonio Capolupo; Giuseppe Vitiello
2013-11-12T23:59:59.000Z
The presence of noncyclic geometric invariant is revealed in all the phenomena where particle generation from vacuum or vacuum condensates appear. Aharonov--Anandan invariants then can help to study such systems and can represent a new tool to be used in order to provide laboratory evidence of phenomena particulary hard to be detected, such as Hawking and Unruh effects and some features of quantum field theory in curved space simulated by some graphene morphologies. It is finally suggested that a very precise quantum thermometer can be built by exploiting geometric invariants properties.
Freezing a Coherent Field Growth in a Cavity by Quantum Zeno Effect
Julien Bernu; Samuel Deléglise; Clément Sayrin; Stefan Kuhr; Igor Dotsenko; Michel Brune; Jean-Michel Raimond; Serge Haroche
2008-09-25T23:59:59.000Z
We have frozen the coherent evolution of a field in a cavity by repeated measurements of its photon number. We use circular Rydberg atoms dispersively coupled to the cavity mode for an absorption-free photon counting. These measurements inhibit the growth of a Field injected in the cavity by a classical source. This manifestation of the Quantum Zeno effect illustrates the back action of the photon number determination onto the Field phase. The residual growth of the Field can be seen as a random walk of its amplitude in the two-dimensional phase space. This experiment sheds light onto the measurement process and opens perspectives for active quantum feedback.
Shepelyansky, Dima
arXiv:quant-ph/0407264v130Jul2004 Effects of decoherence and imperfections for quantum algorithms A gates on the stability of various quantum algorithms including the Grover quantum search algorithm and the quantum chaos maps. For the Grover algorithm our numerical and analytical results show existence
Demir, Hilmi Volkan
GaN/GaN light-emitting diodes (LEDs) grown along the polar orientations significantly suffer from the quantum avoiding the electric field in the quantum wells. Consequently, the optical output power and the external quantum efficiency are substantially improved for the LEDs. The ability to self-screen the QCSE using
Unknown
2005-06-30T23:59:59.000Z
to consider non-isochoric effects, by which the error introduced into energy and entropy calculations and the validity of the design were evaluated. The simulations were done for methane over a range of densities from 500 to 25,000 mol m[] (0.05 < p[] < 2...
arXiv:0907.4122v1[cond-mat.mes-hall]23Jul2009 SPIN CURRENTS IN SEMICONDUCTOR
Nikolic, Branislav K.
arXiv:0907.4122v1[cond-mat.mes-hall]23Jul2009 SPIN CURRENTS IN SEMICONDUCTOR NANOSTRUCTURES Handbook on Nanoscience and Technology: Frontiers and Advances Eds. A. V. Narlikar and Y. Y. Fu (Oxford-HALL EFFECT? 8 6 SO COUPLINGS IN LOW-DIMENSIONAL SEMICONDUCTORS 10 6.1 Rashba coupling in bulk 2DEG
Compact modeling of quantum effects in double gate MOSFETs
Wang, Wei
2007-01-01T23:59:59.000Z
However, ultrathin gate oxide will lead to high gate leakagethe high enough oxide barrier confinement leads to zero waveoxide becomes significant. The random dopant fluctuation effects increase with shrinking device size and leads
Hall viscosity from gauge/gravity duality
Omid Saremi; Dam Thanh Son
2011-03-24T23:59:59.000Z
In (2+1)-dimensional systems with broken parity, there exists yet another transport coefficient, appearing at the same order as the shear viscosity in the hydrodynamic derivative expansion. In condensed matter physics, it is referred to as "Hall viscosity". We consider a simple holographic realization of a (2+1)-dimensional isotropic fluid with broken spatial parity. Using techniques of fluid/gravity correspondence, we uncover that the holographic fluid possesses a nonzero Hall viscosity, whose value only depends on the near-horizon region of the background. We also write down a Kubo's formula for the Hall viscosity. We confirm our results by directly computing the Hall viscosity using the formula.
Rebuilding It Better: Greensburg, Kansas, City Hall
D. Egan
2010-04-13T23:59:59.000Z
This document showcases the LEED-Platinum designed Greensburg City Hall, which was rebuilt green, after a massive tornado destroyed Greensburg, Kansas in May 2007.
Henderson Hall's Education and Career Fair
Broader source: Energy.gov [DOE]
Location: Smith Gym, Henderson Hall, Arlington, VAPOC: Donna FriendWebsite: http://www.mccshh.com/EducationCareerFairFall2014.html
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.
September 10, 2010 Web Town Hall about UC Benefits
Leistikow, Bruce N.
September 10, 2010 Web Town Hall about UC Benefits UC leaders will host an online town hall meeting up for an account here: http://www.ustream.tv/login-signup. The Web Town Hall, a first in UC history
A. R. Bosco de Magalhães; J. G. Peixoto de Faria; R. Rossi Jr
2015-05-22T23:59:59.000Z
We investigate the role of the environment in a quantum erasure setup in the cavity quantum electrodynamics domain. Two slightly different schemes are analyzed. We show that the effects of the environment vary when a scheme is exchanged for another. This can be used to estimate the macroscopic parameters related to the system-environment microscopic correlations.
Wu, Zhigang
Quantum Monte Carlo calculations of the energy-level alignment at hybrid interfaces: Role of many; published 29 May 2009 An approach is presented for obtaining a highly accurate description of the energy-level alignment at hybrid interfaces, using quantum Monte Carlo calculations to include many-body effects
Effective Lagrangians for quantum many-body systems
Jens O. Andersen; Tomas Brauner; Christoph P. Hofmann; Aleksi Vuorinen
2014-06-13T23:59:59.000Z
The low-energy and low-momentum dynamics of systems with a spontaneously broken continuous symmetry is dominated by the ensuing Nambu-Goldstone bosons. It can be conveniently encoded in a model-independent effective field theory whose structure is fixed by symmetry up to a set of effective coupling constants. We construct the most general effective Lagrangian for the Nambu-Goldstone bosons of spontaneously broken global internal symmetry up to the fourth order in derivatives. Rotational invariance and spatial dimensionality of one, two or three are assumed in order to obtain compact explicit expressions, but our method is completely general and can be applied without modifications to condensed matter systems with a discrete space group as well as to higher-dimensional theories. The general low-energy effective Lagrangian for relativistic systems follows as a special case. We also discuss the effects of explicit symmetry breaking and classify the corresponding terms in the Lagrangian. Diverse examples are worked out in order to make the results accessible to a wide theoretical physics community.
Vladimir A. Miransky; Igor A. Shovkovy
2015-04-10T23:59:59.000Z
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...
Deformed Hamilton-Jacobi Method in Covariant Quantum Gravity Effective Models
Benrong, Mu; Yang, Haitang
2014-01-01T23:59:59.000Z
We first briefly revisit the original Hamilton-Jacobi method and show that the Hamilton-Jacobi equation for the action $I$ of tunnelings of a fermionic particle from a charged black hole can be written in the same form as that of a scalar particle. For the low energy quantum gravity effective models which respect covariance of the curved spacetime, we derive the deformed model-independent KG/Dirac and Hamilton-Jacobi equations using the methods of effective field theory. We then find that, to all orders of the effective theories, the deformed Hamilton-Jacobi equations can be obtained from the original ones by simply replacing the mass of emitted particles $m$ with a parameter $m_{eff}$ that includes all the quantum gravity corrections. Therefore, in this scenario, there will be no corrections to the Hawking temperature of a black hole from the quantum gravity effects if its original Hawking temperature is independent of the mass of emitted particles. As a consequence, our results show that breaking covariance...
May 20, 2014 Klarman Hall Construction Project Update
Davis, H. Floyd
May 20, 2014 Klarman Hall Construction Project Update The Klarman Hall will sound. At this signal, construction personnel will clear pedestrians from
Building America Top Innovations Hall of Fame Profile - Building...
Top Innovations Hall of Fame Profile - Building Energy Optimization Analysis Method (BEopt) Building America Top Innovations Hall of Fame Profile - Building Energy Optimization...
Building America Top Innovations Hall of Fame Profile - Building...
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...
Effect of laser phase noise on the fidelity of optomechanical quantum memory
Farnaz Farman; Alireza Bahrampour
2015-03-15T23:59:59.000Z
Optomechanical and electromechanical cavities have been widely used in quantum memories and quantum transducers. We theoretically investigate the robustness of opto(electro)-mechanical quan- tum 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, 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 coupling coefficient, 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 drops as well.
Quantum statistical correlations in thermal field theories: Boundary effective theory
Bessa, A. [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, Caixa Postal 1524, 59072-970, Natal, RN (Brazil); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, SP (Brazil); Brandt, F. T. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, SP (Brazil); Carvalho, C. A. A. de; Fraga, E. S. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972, Rio de Janeiro, RJ (Brazil)
2010-09-15T23:59:59.000Z
We show that the one-loop effective action at finite temperature for a scalar field with quartic interaction has the same renormalized expression as at zero temperature if written in terms of a certain classical field {phi}{sub c}, and if we trade free propagators at zero temperature for their finite-temperature counterparts. The result follows if we write the partition function as an integral over field eigenstates (boundary fields) of the density matrix element in the functional Schroedinger field representation, and perform a semiclassical expansion in two steps: first, we integrate around the saddle point for fixed boundary fields, which is the classical field {phi}{sub c}, a functional of the boundary fields; then, we perform a saddle-point integration over the boundary fields, whose correlations characterize the thermal properties of the system. This procedure provides a dimensionally reduced effective theory for the thermal system. We calculate the two-point correlation as an example.
Moroder, Tobias; Curty, Marcos; Luetkenhaus, Norbert [Quantum Information Theory Group, Institut fuer Theoretische Physik I, and Max-Planck Research Group, Institute of Optics, Information and Photonics, Universitaet Erlangen-Nuernberg, Staudtstrasse 7/B2, 91058 Erlangen (Germany)
2006-01-15T23:59:59.000Z
We provide a simple method to obtain an upper bound on the secret key rate that is particularly suited to analyze practical realizations of quantum key distribution protocols with imperfect devices. We consider the so-called trusted device scenario where Eve cannot modify the actual detection devices employed by Alice and Bob. The upper bound obtained is based on the available measurements results, but it includes the effect of the noise and losses present in the detectors of the legitimate users.
Town Hall with Secretary Moniz
Energy Secretary Ernest Moniz; Deputy Secretary of Energy Daniel Poneman
2013-07-18T23:59:59.000Z
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.
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), 2002; Level:5 TablesExports(Journal Article) | SciTech Connect Journal Article: X-rayContract Documents PPPL TheA PhysicsdifferencesEventsExperimental Hall C An
Town Hall with Secretary Moniz
Energy Secretary Ernest Moniz; Deputy Secretary of Energy Daniel Poneman
2013-07-25T23:59:59.000Z
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.
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.
Reid, Scott A.
-Function Analyses of photocatalytic hybrid materials for solar energy conversion James Kincaid Effect in Ozone Formation · Mixed Quantum/Classical Theory for Collisional Energy Transfer: The Intriguing Story of the Iso-Halons Mark Steinmetz (mark
BIOGRAPHIES Randolph Hall: Networks, Emergency Response,
Southern California, University of
BIOGRAPHIES Randolph Hall: Networks, Emergency Response, Mathematical Modeling Hall, the center: Emergency Response Larson, former co-director of the MIT Operations Research Center, was one of the youngest and more than 75 scientific articles, primarily in emergency response, queuing, logistics and workforce
Scanning Hall Probe Microscopy of Magnetic Vortices inVery Underdoped yttrium-barium-copper-oxide
Guikema, Janice Wynn; /SLAC, SSRL
2005-12-02T23:59:59.000Z
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.
Charging effects and quantum crossover in granular superconductors
Granato, E. (LAS, Instituto Nacional de Pesquisas Espaciais, 12.225 Sao Jose dos Campos, Sao Paulo (Brazil)); Continentino, M.A. (Instituto de Fisica, Universidade Federal Fluminense, Outeiro de S.J. Batista s/n, Niteroi, 24.020, Rio de Janeiro (Brazil))
1993-12-01T23:59:59.000Z
The effects of the charging energy in the superconducting transition of granular materials or Josephson-junction arrays are investigated using a pseudo-spin-one model. Within a mean-field renormalization-group approach, we obtain the phase diagram as a function of temperature and charging energy. In contrast to earlier treatments, we find no sign of a reentrant transition in agreement with more recent studies. A crossover line is identified in the nonsuperconducting side of the phase diagram and along which we expect to observe anomalies in the transport and thermodynamic properties. We also study a charge ordering phase, which can appear for large nearest-neighbor Coulomb interaction, and show that it leads to first-order transitions at low temperatures. We argue that, in the presence of charge ordering, a nonmonotonic behavior with decreasing temperature is possible with a maximum in the resistance just before entering the superconducting phase.
Gusev, Guennady
. Bakarov4 , S. Wiedmann5 and J. C. Portal5,6,7 1 Departamento de F´isica, Universidade Federal do Paran-970, S~ao Paulo, SP, Brazil 4 Institute of Semiconductor Physics - Novosibirsk, 630090, Russia 5 GHMFL
Effective Field Theory for the Quantum Electrodynamics of a Graphene Wire
P. Faccioli; E. Lipparini
2009-06-30T23:59:59.000Z
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.
Nuclear quantum effects in water exchange around lithium and fluoride ions
Wilkins, David M; Dang, Liem X
2015-01-01T23:59:59.000Z
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...
A possible cosmological effect on the quantum-to-classical transition
C. L. Herzenberg
2006-03-16T23:59:59.000Z
Although cosmic expansion at very small distances is usually dismissed as entirely inconsequential, these extraordinarily small effects may in fact have a real and significant influence on our world. A calculation suggests that the minute recessional velocities associated with regions encompassed by extended bodies may have a role in creating the distinction between quantum and classical behavior. Using the criterion that the uncertainty in position should be smaller than the size of an object together with estimates based on the range of Hubble velocities extending through the object lead to a threshold size that could provide a fundamental limit distinguishing the realm of objects governed by classical laws from those governed by quantum mechanics.
Thermal vibration of a rectangular single-layered graphene sheet with quantum effects
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
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.
Cavalier, J.; Lemoine, N.; Bonhomme, G. [IJL, Universite de Lorraine, CNRS (UMR 7198), BP 70239, 54506 Vandoeuvre-les-Nancy (France); Tsikata, S. [ICARE, CNRS (UPR 3021), 1C av. de la Recherche Scientifique, 45071 Orleans (France); Honore, C.; Gresillon, D. [LPP, CNRS (UMR 7648), Ecole Polytechnique, 91128 Palaiseau (France)
2012-08-15T23:59:59.000Z
The effect of the collective light scattering diagnostic transfer function is considered in the context of the dispersion relation of the unstable E Multiplication-Sign B mode previously reported. This transfer function is found to have a contribution to the measured frequencies and mode amplitudes which is more or less significant depending on the measurement wavenumbers and angles. After deconvolution, the experimental data are found to be possibly compatible with the idea that the mode frequency in the jet frame (after subtraction of the Doppler effect due to the plasma motion along the thruster axis) is independent of the orientation of the wave vector in the plane orthogonal to the local magnetic field.
Magnetic shielding of a laboratory Hall thruster. II. Experiments
Hofer, Richard R., E-mail: richard.r.hofer@jpl.nasa.gov; Goebel, Dan M.; Mikellides, Ioannis G.; Katz, Ira [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109 (United States)
2014-01-28T23:59:59.000Z
The physics of magnetic shielding in Hall thrusters were validated through laboratory experiments demonstrating essentially erosionless, high-performance operation. The magnetic field near the walls of a laboratory Hall thruster was modified to effectively eliminate wall erosion while maintaining the magnetic field topology away from the walls necessary to retain efficient operation. Plasma measurements at the walls validate our understanding of magnetic shielding as derived from the theory. The plasma potential was maintained very near the anode potential, the electron temperature was reduced by a factor of two to three, and the ion current density was reduced by at least a factor of two. Measurements of the carbon backsputter rate, wall geometry, and direct measurement of plasma properties at the wall indicate that the wall erosion rate was reduced by a factor of 1000 relative to the unshielded thruster. These changes effectively eliminate wall erosion as a life limitation in Hall thrusters, enabling a new class of deep-space missions that could not previously be attempted.
Ko, Suk-Min; Kwack, Ho-Sang; Park, Chunghyun; Yoo, Yang-Seok; Cho, Yong-Hoon, E-mail: yhc@kaist.ac.kr [Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)] [Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Kwon, Soon-Yong [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of) [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Jin Kim, Hee; Yoon, Euijoon, E-mail: eyoon@snu.ac.kr [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Si Dang, Le [Nanophysics and Semiconductors, CEA-CNRS-UJF Group, Institut Néel, CNRS Grenoble, 25 rue des Martyrs, 38042 Grenoble Cedex 9 (France)] [Nanophysics and Semiconductors, CEA-CNRS-UJF Group, Institut Néel, CNRS Grenoble, 25 rue des Martyrs, 38042 Grenoble Cedex 9 (France)
2013-11-25T23:59:59.000Z
Here, we report on the optical and structural characteristics of violet-light-emitting, ultra-thin, high-Indium-content (UTHI) InGaN/GaN multiple quantum wells (MQWs), and of conventional low-In-content MQWs, which both emit at similar emission energies though having different well thicknesses and In compositions. The spatial inhomogeneity of In content, and the potential fluctuation in high-efficiency UTHI MQWs were compared to those in the conventional low-In-content MQWs. We conclude that the UTHI InGaN MQWs are a promising structure for achieving better quantum efficiency in the visible and near-ultraviolet spectral range, owing to their strong carrier localization and reduced quantum-confined Stark effect.
Petta, Jason
of termination of enrollment and submitted to the Office of Academic Affairs of the Graduate School in Clio Hall for Termination (Select one of the items below): r All degree requirements have been completed. Date of Final Public Oral Examination (where applicable): r Enrollment Terminated, Degree Candidacy Continues (ET
Drew, H. Dennis
. Schmadel,1 G. S. Jenkins,1 H. D. Drew,1 R. Hughes,2 A. Dabkowski,2 J. S. Preston,2 and P.-J. Kung3 1 Center in High-Tc Superconductors: Evidence for Non-Fermi-Liquid Hall Scattering J. Cerne,1, * M. Grayson,1 D. C
Quantum Mechanical Inclusion of the Source in the Aharonov-Bohm Effect
Philip Pearle; Anthony Rizzi
2015-06-30T23:59:59.000Z
The standard treatment of the magnetic Aharonov-Bohm (A-B) effect assumes one can calculate the phase without accounting for the source (solenoid) quantum mechanically. Recently, Vaidman, using a semi-classical calculation, showed that the source may indeed matter. He argued for what might be called a local field hypothesis---the idea that in quantum theory, as in classical physics, only field-producing potentials have physical effects. His calculation indicates that the electron's non-relativistic electric field, acting on a semi-classically treated solenoid, produces the A-B phase shift. Here, employing a model of the solenoid consisting of charged particles, we give a quantum mechanical treatment of their contribution to the phase shift under the influence of the circulating electron's electric field. We show that the phase shift of the field-producing non-relativistic vector potential gives the A-B phase shift, and how this confirms Vaidman's semi-classical prediction of that phase shift. However, we also show that the phase shift of the field-producing relativistic (retarded) scalar potential gives the negative of the A-B phase shift. This cancellation allows one to effectively treat the source as a classical entity as is done in the standard derivation of the A-B effect. We close by remarking that the apparent necessity for relativistic considerations suggests the possibility that the A-B phase shift may yet be explained in terms of field-producing potentials alone, which may vindicate the local field hypothesis.
Mode transition of a Hall thruster discharge plasma
Hara, Kentaro, E-mail: kenhara@umich.edu; Sekerak, Michael J., E-mail: msekerak@umich.edu; Boyd, Iain D.; Gallimore, Alec D. [University of Michigan, Ann Arbor, Michigan 48109 (United States)
2014-05-28T23:59:59.000Z
A Hall thruster is a cross-field plasma device used for spacecraft propulsion. An important unresolved issue in the development of Hall thrusters concerns the effect of discharge oscillations in the range of 10–30?kHz on their performance. The use of a high speed Langmuir probe system and ultra-fast imaging of the discharge plasma of a Hall thruster suggests that the discharge oscillation mode, often called the breathing mode, is strongly correlated to an axial global ionization mode. Stabilization of the global oscillation mode is achieved as the magnetic field is increased and azimuthally rotating spokes are observed. A hybrid-direct kinetic simulation that takes into account the transport of electronically excited atoms is used to model the discharge plasma of a Hall thruster. The predicted mode transition agrees with experiments in terms of the mean discharge current, the amplitude of discharge current oscillation, and the breathing mode frequency. It is observed that the stabilization of the global oscillation mode is associated with reduced electron transport that suppresses the ionization process inside the channel. As the Joule heating balances the other loss terms including the effects of wall loss and inelastic collisions, the ionization oscillation is damped, and the discharge oscillation stabilizes. A wide range of the stable operation is supported by the formation of a space charge saturated sheath that stabilizes the electron axial drift and balances the Joule heating as the magnetic field increases. Finally, it is indicated from the numerical results that there is a strong correlation between the emitted light intensity and the discharge current.
Shepelyansky, Dima
of various applica- tions in quantum computation, including the simulation of quantum chaos models showing, including treatment of large databases, data and image compression, signal process- ing, telecommunications
Miller, David A. B.
Ge/SiGe Quantum Confined Stark Effect Modulators on Silicon James S. Harris, Yu-Hsuan Kuo bandwidth have been demonstrated [4]. 2. Quantum well design Ge is an indirect band gap material, but it has. In order to have good quantum confinement, SiGe barriers are used since Si and Ge have a very high direct
Gravitational quantum effects on power spectra and spectral indices with higher-order corrections
Tao Zhu; Anzhong Wang; Gerald Cleaver; Klaus Kirsten; Qin Sheng
2014-09-05T23:59:59.000Z
The uniform asymptotic approximation method provides a powerful, systematically-improved, and error-controlled approach to construct accurate analytical approximate solutions of mode functions of perturbations of the Friedmann-Robertson-Walker universe, designed especially for the cases where the relativistic linear dispersion relation is modified after gravitational quantum effects are taken into account. These include models from string/M-Theory, loop quantum cosmology and Ho\\v{r}ava-Lifshitz quantum gravity. In this paper, we extend our previous studies of the first-order approximations to high orders for the cases where the modified dispersion relation (linear or nonlinear) has only one-turning point (or zero). We obtain the general expressions for the power spectra and spectral indices of both scalar and tensor perturbations up to the third-order, at which the error bounds are $\\lesssim 0.15\\%$. As an application of these formulas, we calculate the power spectra and spectral indices in the slow-roll inflation with a nonlinear power-law dispersion relation. To check the consistency of our formulas, we further restrict ourselves to the relativistic case, and calculate the corresponding power spectra, spectral indices and runnings to the second-order. Then, we compare our results with the ones obtained by the Green function method, and show explicitly that the results obtained by these two different methods are consistent within the allowed errors.
Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system
Emmanuele Battista; Simone Dell'Agnello; Giampiero Esposito; Jules Simo
2015-03-31T23:59:59.000Z
Recent work in the literature has shown that the one-loop 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 prove in detail that also for collinear Lagrangian points the quantum corrections are of the same order of magnitude in the Earth-Moon system. Third, 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 one-loop quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.
Stapp, Henry P.
2011-05-10T23:59:59.000Z
The principle of sufficient reason asserts that anything that happens does so for a reason: no definite state of affairs can come into being unless there is a sufficient reason why that particular thing should happen. This principle is usually attributed to Leibniz, although the first recorded Western philosopher to use it was Anaximander of Miletus. The demand that nature be rational, in the sense that it be compatible with the principle of sufficient reason, conflicts with a basic feature of contemporary orthodox physical theory, namely the notion that nature's response to the probing action of an observer is determined by pure chance, and hence on the basis of absolutely no reason at all. This appeal to pure chance can be deemed to have no rational fundamental place in reason-based Western science. It is argued here, on the basis of the other basic principles of quantum physics, that in a world that conforms to the principle of sufficient reason, the usual quantum statistical rules will naturally emerge at the pragmatic level, in cases where the reason behind nature's choice of response is unknown, but that the usual statistics can become biased in an empirically manifest way when the reason for the choice is empirically identifiable. It is shown here that if the statistical laws of quantum mechanics were to be biased in this way then the basically forward-in-time unfolding of empirical reality described by orthodox quantum mechanics would generate the appearances of backward-time-effects of the kind that have been reported in the scientific literature.
Georgiou, C. [Research Unit for Nanostructured Materials Systems, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol (Cyprus); Leontiou, T. [Research Unit for Nanostructured Materials Systems, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol (Cyprus); General Department, Frederich University, 1036 Nicosia (Cyprus); Kelires, P. C., E-mail: pantelis.kelires@cut.ac.cy [Research Unit for Nanostructured Materials Systems, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol (Cyprus); Department of Mechanical and Materials Science Engineering, Cyprus University of Technology, P.O. Box 50329, 3603 Limassol (Cyprus)
2014-07-15T23:59:59.000Z
Atomistic Monte Carlo simulations, coupling thermodynamic and kinetic effects, resolve a longstanding controversy regarding the origin of composition profiles in heteroepitaxial SiGe quantum dots. It is shown that profiles with cores rich in the unstrained (Si) component derive from near-equilibrium processes and intraisland diffusion. Profiles with cores rich in the strained (Ge) component are of nonequilibrium nature, i.e., they are strain driven but kinetically limited. They are shaped by the distribution of kinetic barriers of atomic diffusion in the islands. The diffusion pathways are clearly revealed for the first time. Geometrical kinetics play a minor role.
Effects of geometry and impurities on quantum rings in magnetic fields RID D-3014-2009
Aichinger, M.; Chin, Siu A.; Krotscheck, E.; Rasanen, E.
2006-01-01T23:59:59.000Z
Effects of geometry and impurities on quantum rings in magnetic fields M. Aichinger,1,2 S. A. Chin,3,* E. Krotscheck,1,? and E. R?s?nen1,4,? 1Institut f?r Theoretische Physik, Johannes Kepler Universit?t, A-4040 Linz, Austria 2Department... for Medical-Informatics, Upper Austrian Research, Hauptstrasse 99, A-4232 Hagenberg, Austria 3Department of Physics, Texas A&M University College Station, Texas 77843-4242, USA 4Institut f?r Theoretische Physik, Freie Universit?t Berlin, Arnimallee 14, D...
A new town hall for Norwich, Vermont
Harboe, Peter Thomas McIlvaine
1988-01-01T23:59:59.000Z
... the public building is not an abstract symbol, but partakes in daily life, which relates to what is timeless and common. The objective of this thesis was to design a new town hall for Norwich, Vermont. The design ...
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...
Towards a graphene-based quantum impedance standard
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
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.
Steric, Quantum, and Electrostatic Effects on S{sub N}2 Reaction Barriers in Gas Phase
Liu, Shubin; Hu, Hao; Pedersen, Lee G.
2010-05-13T23:59:59.000Z
Biomolecular nucleophilic substitution reactions, S{sub N}2, are fundamental and commonplace in chemistry. It is the well-documented experimental finding in the literature that vicinal substitution with bulkier groups near the reaction center significantly slows the reaction due to steric hindrance, but theoretical understanding in the quantitative manner about factors dictating the S{sub N}2 reaction barrier height is still controversial. In this work, employing the new quantification approach that we recently proposed for the steric effect from the density functional theory framework, we investigate the relative contribution of three independent effects—steric, electrostatic, and quantum—to the S{sub N}2 barrier heights in gas phase for substituted methyl halide systems, R{sub 1}R{sub 2}R{sub 3}CX, reacting with the fluorine anion, where R{sub 1}, R{sub 2}, and R{sub 3} denote substituting groups and X = F or Cl. We found that in accordance with the experimental finding, for these systems, the steric effect dominates the transition state barrier, contributing positively to barrier heights, but this contribution is largely compensated by the negative, stabilizing contribution from the quantum effect due to the exchange-correlation interactions. Moreover, we find that it is the component from the electrostatic effect that is linearly correlated with the S{sub N}2 barrier height for the systems investigated in the present study. In addition, we compared our approach with the conventional method of energy decomposition in density functional theory as well as examined the steric effect from the wave function theory for these systems via natural bond orbital analysis.
Minnesota, University of
1 Hybrid Quantum and Classical Methods for Computing Kinetic Isotope Effects of Chemical Reactions for computing kinetic isotope effects for chemical reactions in solution and in enzymes. In the ensemble that enzymes accelerate the rates of chemical reactions has fascinated chemists and biochemists for nearly
On the dual topological quantum numbers filling factors
Wellington da Cruz
2003-05-26T23:59:59.000Z
We consider recent experimental results [W. Pan {\\it et al}, Phys. Rev. Lett. {\\bf 90}, 016801 (2003)] for occurrence of the fractional quantum Hall effect-FQHE under the perspective of our formulation in terms of {\\it fractons}. These objects carry rational or irrational values of spin and satisfy a {\\it fractal distribution function} associated with a {\\it fractal von Neumann entropy}. According to our approach the {\\it FQHE occurs in pairs of dual topological quantum numbers fillings factors} and this geometrical character comes from the {\\it connection betwenn the fractal parameter or Hausdorff dimension $h$ and the spin $s$ of the particles}. We suggest to the experimentalists consider our ideas and verify in fact that this phenomenon of FQHE satisfy a {\\it symmetry principle} discovered by us, i.e, {\\it the duality symmetry betwenn universal classes of fractons}.
Kalisz, Susan
F1 · Old Engineering Hall ....................OEH D2 Oxford Bldg.(3501 Forbes Ave.) OXFRD C4.............................BELLH G2 Bellefield Presbyterian Church...PRES D3 Bellefield Towers.........................BELLT F1 ....................CHILD C3 Clapp Hall..................................CLAPP F1 Community of Reconciliation Bldg. ..CR F1
Spin hall effect in paramagnetic thin films
Xu, Huachun
2009-05-15T23:59:59.000Z
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...
Spin hall effect in paramagnetic thin films
Xu, Huachun
2009-05-15T23:59:59.000Z
students Dr. Zuxin Ye, Haidong Liu, and Hong Zhang let me using their electroplating systems and generously provided valuable suggestions when I built an electroplating system. The machine shop and the electronic shop in the Physics Department helped a... .................................................................. 24 2.3 Pattern transferring.............................................................................. 33 2.4 Thin film deposition ............................................................................ 34 2.5 Electroplating...
Controlling atomistic processes on Pb films via quantum size effects and lattice rotation
Binz, Steven
2012-06-14T23:59:59.000Z
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.
Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells
Zhengping Jiang; Neerav Kharche; Timothy Boykin; Gerhard Klimeck
2012-03-06T23:59:59.000Z
A sharp potential barrier at the Si/SiGe interface introduces valley splitting (VS), which lifts the 2-fold valley degeneracy in strained SiGe/Si/SiGe quantum wells (QWs). This work examines in detail the effects of Si/SiGe interface disorder on the VS in an atomistic tight binding approach based on statistical sampling. VS is analyzed as a function of electric field, QW thickness, and simulation domain size. Strong electric fields push the electron wavefunctions into the SiGe buffer and introduce significant VS fluctuations from device to device. A Gedankenexperiment with ordered alloys sheds light on the importance of different bonding configurations on VS. We conclude that a single SiGe band offset and effective mass cannot comprehend the complex Si/SiGe interface interactions that dominate VS.
Effects of Interface Disorder on Valley Splitting in SiGe/Si/SiGe Quantum Wells
Jiang, Zhengping; Boykin, Timothy; Klimeck, Gerhard
2011-01-01T23:59:59.000Z
A sharp potential barrier at the Si/SiGe interface introduces valley splitting (VS), which lifts the 2-fold valley degeneracy in strained SiGe/Si/SiGe quantum wells (QWs). This work examines in detail the effects of Si/SiGe interface disorder on the VS in an atomistic tight binding approach based on statistical sampling. VS is analyzed as a function of electric field, QW thickness, and simulation domain size. Strong electric fields push the electron wavefunctions into the SiGe buffer and introduce significant VS fluctuations from device to device. A Gedankenexperiment with ordered alloys sheds light on the importance of different bonding configurations on VS. We conclude that a single SiGe band offset and effective mass cannot comprehend the complex Si/SiGe interface interactions that dominate VS.
Baishali Chakraborty; Kumar S. Gupta; Siddhartha Sen
2012-08-03T23:59:59.000Z
We study the combined effect of a conical topological defect and a Coulomb charge impurity on the dynamics of Dirac fermions in gapped graphene. Beyond a certain strength of the Coulomb charge, quantum instability sets in, which demarcates the boundary between sub and supercritical values of the charge. In the subcritical regime, for certain values of the system parameters, the allowed boundary conditions in gapped graphene cone can be classified in terms of a single real parameter. We show that the observables such as local density of states, scattering phase shifts and the bound state spectra are sensitive to the value of this real parameter, which is interesting from an empirical point of view. For a supercritical Coulomb charge, we analyze the system with a regularized potential as well as with a zigzag boundary condition and find the effect of the sample topology on the observable features of the system.
Blinking effect and the use of quantum dots in single molecule spectroscopy
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
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.
When is a quantum heat engine quantum?
Alexander Friedenberger; Eric Lutz
2015-08-17T23:59:59.000Z
Quantum thermodynamics studies quantum effects in thermal machines. But when is a heat engine, which cyclically interacts with external reservoirs that unavoidably destroy its quantum coherence, really quantum? We here use the Leggett-Garg inequality to assess the nonclassical properties of a single two-level Otto engine. We provide the complete phase diagram characterizing the quantumness of the engine as a function of its parameters and identify three distinct phases. We further derive an explicit expression for the transition temperature.
Effect of Ligands on Characteristics of (CdSe)13 Quantum Dot
Gao, Yang; Zhou, Bo; Kang, Seung-gu; Xin, Minsi; Yang, Ping; Dai, Xing; Wang, Zhigang; Zhou, Ruhong
2014-01-01T23:59:59.000Z
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.
Exponential Decay and Fermi's Golden Rule from an Uncontrolled Quantum Zeno Effect
P. W. Bryant
2014-10-14T23:59:59.000Z
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.
Local dissipation effects in two-dimensional quantum Josephson junction arrays with a 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
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.
Effective Landé factor in a GaMnAs quantum dot; with the effects of sp-d exchange on a bound polaron
Lalitha, D., E-mail: a.john.peter@gmail.com; Peter, A. John, E-mail: a.john.peter@gmail.com [Dept. of Physics, Government Arts College, Melur-625106, Tamilnadu (India)
2014-04-24T23:59:59.000Z
The effective g-factor of conduction (valence) band electron (hole) is obtained in the GaMnAs quantum dot. Magneto bound polaron in a GaMnAs/Ga{sub 0.6}Al{sub 0.4}As quantum dot is investigated with the inclusion of exchange interaction effects due to Mn alloy content and the geometrical confinement. The spin polaronic energy of the heavy hole exciton is studied with the spatial confinement using a mean field theory in the presence of magnetic field strength.
Khan, Shabbir A
2013-01-01T23:59:59.000Z
Quantum plasma physics is a rapidly evolving research field with a very inter-disciplinary scope of potential applications, ranging from nano-scale science in condensed matter to the vast scales of astrophysical objects. The theoretical description of quantum plasmas relies on various approaches, microscopic or macroscopic, some of which have obvious relation to classical plasma models. The appropriate model should, in principle, incorporate the quantum mechanical effects such as diffraction, spin statistics and correlations, operative on the relevant scales. However, first-principle approaches such as quantum Monte Carlo and density functional theory or quantum-statistical methods such as quantum kinetic theory or non-equilibrium Green's functions require substantial theoretical and computational efforts. Therefore, for selected problems, alternative simpler methods have been put forward. In particular, the collective behavior of many-body systems is usually described within a self-consistent scheme of parti...
Microsoft Word - Town-Hall-meeting_notes_090215.docx
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), 2002; Level:5 TablesExports(Journal Article)41clothThe Bonneville PowerTariff Pages default SignEnergy4 3. EFFECTIVE DATE (M/D/Y) See9, 19983, 19980,Group Town Hall
Microwave generation by spin Hall nanooscillators with nanopatterned spin injector
Zholud, A., E-mail: azholud@emory.edu; Urazhdin, S. [Department of Physics, Emory University, Atlanta, Georgia 30322 (United States)
2014-09-15T23:59:59.000Z
We experimentally study spin Hall nano-oscillators based on Pt/ferromagnet bilayers with nanopatterned Pt spin injection layer. We demonstrate that both the spectral characteristics and the electrical current requirements can be simultaneously improved by reducing the spin injection area. Moreover, devices with nanopatterned Pt spin injector exhibit microwave generation over a wide temperature range that extends to room temperature. Studies of devices with additional Pt spacers under the device electrodes show that the oscillation characteristics are affected not only by the spin injection geometry but also by the effects of Pt/ferromagnet interface on the dynamical properties of the ferromagnet.
TRINITY HALL HAS INSTALLED CCTV ON THESE PREMISES FOR
Lasenby, Joan
TRINITY HALL HAS INSTALLED CCTV ON THESE PREMISES FOR YOUR SAFETY AND PROTECTION #12; Trinity Hall Trinity Lane Cambridge CB2 1TJ Tel: 01223 33 25 00 For all enquiries and questions
Spring 2015 Henderson Hall Education and Career Fair | Department...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Henderson Hall Education and Career Fair April 2, 2015 10:00AM to 1:00PM EDT Location: Smith Gym, Henderson Hall, Arlington, VA POC: DOECorporateRecruitment@hq.doe.gov Website:...
Tahir, M. [PSE Division, KAUST, Thuwal 23955-6900 (Saudi Arabia); Department of Physics, University of Sargodha, Sargodha 40100 (Pakistan); Sabeeh, K. [Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Shaukat, A. [Department of Physics, University of Sargodha, Sargodha 40100 (Pakistan); Schwingenschlögl, U., E-mail: Udo.Schwingenschlogl@kaust.edu.sa [PSE Division, KAUST, Thuwal 23955-6900 (Saudi Arabia)
2013-12-14T23:59:59.000Z
Since the discovery of graphene, a lot of interest has been attracted by the zeroth Landau level, which has no analog in the conventional two dimensional electron gas. Recently, lifting of the spin and valley degeneracies has been confirmed experimentally by capacitance measurements, while in transport experiments, this is difficult due to the scattering in the device. In this context, we model interaction effects on the quantum capacitance of graphene in the presence of a perpendicular magnetic field, finding good agreement with experiments. We demonstrate that the valley degeneracy is lifted by the substrate and by Kekule distortion, whereas the spin degeneracy is lifted by Zeeman interaction. The two cases can be distinguished by capacitance measurements.
Towards a Robust, Efficient Dispenser Photocathode: the Effect of Recesiation on Quantum Efficiency
Montgomery, Eric J.; Pan Zhigang; Leung, Jessica; Feldman, Donald W.; O'Shea, Patrick G. [Institute for Research in Electronics and Applied Physics, University of MD, College Park, MD 20742 (United States); Jensen, Kevin L. [Code 6843, ESTD, Naval Research Laboratory, Washington D.C. 20375-5347 (United States)
2009-01-22T23:59:59.000Z
Future electron accelerators and Free Electron Lasers (FELs) require high brightness electron sources; photocathodes for such devices are challenged to maintain long life and high electron emission efficiency (high quantum efficiency, or QE). The UMD dispenser photocathode design addresses this tradeoff of robustness and QE. In such a dispenser, a cesium-based surface layer is deposited on a porous substrate. The surface layer can be replenished from a subsurface cesium reservoir under gentle heating, allowing cesium to diffuse controllably to the surface and providing demonstrably more robust photocathodes. In support of the premise that recesiation is able to restore contaminated photocathodes, we here report controlled contamination of cesium-based surface layers with subsequent recesiation and the resulting effect on QE. Contaminant gases investigated include examples known from the vacuum environment of typical electron guns.
Suspending Effect on Low-Frequency Charge Noise in Graphene Quantum Dot
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
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.
Quantum Otto cycle with inner friction: finite-time and disorder effects
A. Alecce; F. Galve; N. Lo Gullo; L. Dell'Anna; F. Plastina; R. Zambrini
2015-07-13T23:59:59.000Z
The concept of inner friction, by which a quantum heat engine is unable to follow adiabatically its strokes and thus dissipates useful energy, is illustrated in an exact physical model where the working substance consists of an ensemble of misaligned spins interacting with a magnetic field and performing the Otto cycle. The effect of this static disorder under a finite-time cycle gives a new perspective of the concept of inner friction under realistic settings. We investigate the efficiency and power of this engine and relate its performance to the amount of friction from misalignment and to the temperature difference between heat baths. Finally we propose an alternative experimental implementation of the cycle where the spin is encoded in the degree of polarization of photons.
Reduced quantum confinement effect and electron-hole separation in SiGe nanowires Michele Amato,1
Marini, Andrea
Reduced quantum confinement effect and electron-hole separation in SiGe nanowires Michele Amato,1 Using first-principles methods, we investigate the structural and electronic properties of SiGe26 studies have been carried out to investigate the structural and optoelectronic properties of Si, Ge
Martinis, John M.
2013-01-01T23:59:59.000Z
PHYSICAL REVIEW A 88, 062329 (2013) Understanding the effects of leakage in superconducting quantum of leakage in a two-qubit superconducting stabilizer measurement circuit. We simulate the repeated ancilla is important for superconducting qubits not only because higher-energy states |2 ,|3 , . . . are present [4
Checklists for: Oklahoma 4-H Hall of Fame
Balasundaram, Balabhaskar "Baski"
Checklists for: Oklahoma 4-H Hall of Fame National 4-H Youth Congress Name County Oklahoma 4-H Hall of Fame National 4-H Youth Congress Oklahoma 4-H Hall of Fame has the following requirements: Oklahoma 4-H on the front page of the Oklahoma 4-H Report Form and on the heading for Section I Member must be 16 years
Making a gift: Trinity Hall is a registered charity
Lasenby, Joan
Making a gift: Trinity Hall is a registered charity and gifts to the College can be made tax. For more information please see: www.trinhall.cam.ac.uk/giving2012 Development Office, Trinity Hall)1223 765157 Trinity Hall Cambridge registered charity number 1137458 "Receiving funding has made a huge
Martin--Luther--Universit at Halle--Wittenberg
Liebenow, N. H. Cong, R. Weiner and K. Strehmel Report No. 41 (1997) Reports of the Institute of Numericaldimensional parabolic differential equations C. EichlerLiebenow, N. H. Cong, R. Weiner and K. Strehmel Report No. 41@mail.mathematik.unihalle.de rw@mathematik.unihalle.de strehmel@mathematik.unihalle.de Prof. Dr. N. H. Cong Faculty
, such as the study of superconductivity and the fractional quantum hall effect, are devoted to understanding
Non-linear hydrodynamics of axion dark matter: relative velocity effects and "quantum forces"
Marsh, David J E
2015-01-01T23:59:59.000Z
The non-linear hydrodynamic equations for axion/scalar field dark matter (DM) in the non-relativistic Madelung-Shcr\\"{o}dinger form are derived in a simple manner, including the effects of universal expansion and Hubble drag. The hydrodynamic equations are used to investigate the relative velocity between axion DM and baryons, and the moving-background perturbation theory (MBPT) derived. Axions massive enough to be all of the DM do not affect the coherence length of the relative velocity, but the MBPT equations are modified by the inclusion of the axion effective sound speed. These MBPT equations are necessary for accurately modelling the effects of axion DM on the formation of the first cosmic structures, and suggest that the 21cm power spectrum could improve constraints on axion mass by up to four orders of magnitude with respect to the current best constraints. A further application of these results uses the "quantum force" analogy to model scalar field gradient energy in a smoothed-particle hydrodynamics ...
J. Wurm; K. Richter; I. Adagideli
2011-11-14T23:59:59.000Z
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.
Noncontact semiconductor wafer characterization with the terahertz Hall D. M. Mittleman,a)
Natelson, Douglas
of Physics. S0003-6951 97 01427-7 Doped semiconductors are frequently characterized by two material properties and quality. They also determine many of the electrical and optical properties of the material. NNoncontact semiconductor wafer characterization with the terahertz Hall effect D. M. Mittleman,a) J
Jussi Ilmari Lindgren
2013-02-13T23:59:59.000Z
This paper defines an equation for causality. This equation is then combined with the postulates of quantum mechanics and mass-energy equivalence to produce a quantum mechanical telegrapher's equation and to reproduce the Schrodinger and Klein-Gordon equations. The incompressible Navier-Stokes equations and dynamic general equilibrium in economics (with an interpretation of a Nash equilibrium) are obtained when the equation of causality refers to itself, i.e. when the cause is its own effect. As it is shown that the Klein-Gordon equation is obtained by Wick rotating the cause vector with de Broglie angular frequency, this paper postulates an equation for Quantum Gravity, which relates the Navier-Stokes equations to the Einstein Field Equations of General Relativity.
Local Availability of mathematics and number scaling: Effects on quantum physics
Paul Benioff
2012-05-01T23:59:59.000Z
Local availability of mathematics and number scaling provide an approach to a coherent theory of physics and mathematics. Local availability of mathematics assigns separate mathematical universes, U_{x}, to each space time point, x. The mathematics available to an observer, O_{x}, at x is contained in U_{x}. Number scaling is based on extending the choice freedom of vector space bases in gauge theories to choice freedom of underlying number systems. Scaling arises in the description, in U_{x}, of mathematical systems in U_{y}. If a_{y} or \\psi_{y} is a number or a quantum state in U_{y}, then the corresponding number or state in U_{x} is r_{y,x}a_{x} or r_{y,x}\\psi_{x}. Here a_{x} and \\psi_{x} are the same number and state in U_{x} as a_{y} and \\psi_{y} are in U_{y}. If y=x+\\hat{\\mu}dx is a neighbor point of x, then the scaling factor is r_{y,x}=\\exp(\\vec{A}(x)\\cdot\\hat{\\mu}dx) where \\vec{A} is a vector field, assumed here to be the gradient of a scalar field. The effects of scaling and local availability of mathematics on quantum theory show that scaling has two components, external and internal. External scaling is shown above for a_{y} and \\psi_{y}. Internal scaling occurs in expressions with integrals or derivatives over space or space time. An example is the replacement of the position expectation value, \\int\\psi^{*}(y)y\\psi(y)dy, by \\int_{x}r_{y,x}\\psi^{*}_{x}(y_{x})y_{x}\\psi_{x}(y_{x})dy_{x}. This is an integral in U_{x}. The good agreement between quantum theory and experiment shows that scaling is negligible in a space region, L, in which experiments and calculations can be done, and results compared. L includes the solar system, but the speed of light limits the size of L to a few light years. Outside of $L$, at cosmological distances, the limits on scaling are not present.
SPROUL HALL 1124 RIVERSIDE, CA 92521
SPROUL HALL 1124 RIVERSIDE, CA 92521 education.ucr.edu TEACHER EDUCATION SERVICES (951) 827 School of Education teacher preparation program. For application information please go to the website and view Teacher Education Admission requirements http://education.ucr.edu/tcadmissions.html *Multiple
Alan Turing, Marshall Hall, and the Alignment
Wright, Francis
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
U.S. WRESTLING FEDERATION HALL
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 CORDELL ATHLETIC CENTER BOONE PICKENS STADIUM ANIMAL SCIENCES AGRICULTURAL SCIENCES MATH N. SMITH HALL ALUMNI CENTER HOUSING - JPI PHASE 1 BUILDING 3 HOUSING - JPI PHASE 1 BUILDING 4 STUDENT UNION
The practical revised simplex method Julian Hall
Hall, Julian
The practical revised simplex method Julian Hall School of Mathematics University of Edinburgh January 25th 2007 The practical revised simplex method #12;Overview #12;Overview Part 1: · The mathematics of linear programming #12;Overview Part 1: · The mathematics of linear programming · The simplex method
Start: Statler Hotel (star) Finish: Upson Hall
Keinan, Alon
route: Green dashed line that starts from Statler Hotel and meets read line (backwards) at Bailey Hall been accomplished by a pair of local rock climbers. Uris Library (around towards the Slope) o Show west campus, downtown, Cayuga lake Uris Library (inside) o Cornell has 19 libraries which hold more
Light Board Operation 208 Jordan Hall
Buechler, Steven
Light Board Operation 208 Jordan Hall Using the Light Board 1. Turn on the lights next to the entry door. 2. Turn on the Light Board lights (illustration 1). The light switch is on the west wall, slightly behind the computer cart's display. 3. Locate the lapel microphone (usually on top of the Light
235 Clements Hall Math Department, SMU
Xu, Sheng
Sheng Xu 235 Clements Hall Math Department, SMU Dallas, TX 75275-0156 (214) 768-2985(O), (214)768-2355(F) sxu@smu.edu http://faculty.smu.edu/sxu computational fluid dynamics and scientific computing (SMU) Engineer, April 2006 - July 2006 Steam Turbine Aerodynamics Group, GE Energy Post
Topological Quantum Computation I Eric Rowell
Rowell, Eric C.
phases. Fractional Quantum Hall Liquid 1011 electrons/cm2 Bz 10 Tesla quasi-particles T 9 mK #12;The Braid Group A key role is played by the braid group: Definition Bn is generated by i , i = 1, . . . , n
Disorder and interactions in quantum Hall ferromagnets near nu=1.
Sinova, Jairo; MacDonald, AH; Girvin, SM.
2000-01-01T23:59:59.000Z
Message Passing Interface (MPI) is a standard library interface for writing parallel programs. The MPI specification is broadly used for solving engineering and scientific problems on parallel computers, and MPICH2 is a ...
Scaling in the quantum Hall regime of graphene Corbino 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
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.
Topological Hubbard Model and Its High-Temperature Quantum Hall...
Office of Scientific and Technical Information (OSTI)
Sponsoring Org: USDOE Country of Publication: United States Language: English Word Cloud More Like This Free Publicly Accessible Full Text Publisher's Accepted Manuscript at...
Sai Vinjanampathy; Janet Anders
2015-08-25T23:59:59.000Z
Quantum thermodynamics is an emerging research field aiming to extend standard thermodynamics and non-equilibrium statistical physics to ensembles of sizes well below the thermodynamic limit, in non-equilibrium situations, and with the full inclusion of quantum effects. Fuelled by experimental advances and the potential of future nanoscale applications this research effort is pursued by scientists with different backgrounds, including statistical physics, many-body theory, mesoscopic physics and quantum information theory, who bring various tools and methods to the field. A multitude of theoretical questions are being addressed ranging from issues of thermalisation of quantum systems and various definitions of "work", to the efficiency and power of quantum engines. This overview provides a perspective on a selection of these current trends accessible to postgraduate students and researchers alike.
Minnesota, University of
Systematic Approach for Computing Zero-Point Energy, Quantum Partition Function, and Tunneling, and a proton-transfer barrier modeled by the Eckart potential. The zero-point energy, quantum partition agreement with the ground-state energy (zero-point energy), and the position of the centroid potential
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
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.
The impact of Hall physics on magnetized high energy density plasma jets
Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A. [Cornell University, Ithaca, New York 14853 (United States)] [Cornell University, Ithaca, New York 14853 (United States)
2014-05-15T23:59:59.000Z
Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e}???10{sup 19}?cm{sup ?3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (?1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10?T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)
A functional approach to quantum friction: effective action and dissipative force
M. Belén Farías; César D. Fosco; Fernando C. Lombardo; Francisco D. Mazzitelli; Adrián E. Rubio López
2014-12-31T23:59:59.000Z
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 $\\phi$
Effect of graphene on photoluminescence properties of graphene/GeSi quantum dot hybrid 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
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.
of Matter, Transport and Energy #12;T) due to quantum confinement effects. Improving the efficiency of thermoelectric devices allows. Thermal conductivity measurement systems are an important part of the characterization processes
Fast Camera Imaging of Hall Thruster Ignition
C.L. Ellison, Y. Raitses and N.J. Fisch
2011-02-24T23:59:59.000Z
Hall thrusters provide efficient space propulsion by electrostatic acceleration of ions. Rotating electron clouds in the thruster overcome the space charge limitations of other methods. Images of the thruster startup, taken with a fast camera, reveal a bright ionization period which settles into steady state operation over 50 ?s. The cathode introduces azimuthal asymmetry, which persists for about 30 ?s into the ignition. Plasma thrusters are used on satellites for repositioning, orbit correction and drag compensation. The advantage of plasma thrusters over conventional chemical thrusters is that the exhaust energies are not limited by chemical energy to about an electron volt. For xenon Hall thrusters, the ion exhaust velocity can be 15-20 km/s, compared to 5 km/s for a typical chemical thruster
Interpretation of cosmological expansion effects on the quantum-classical transition
C. L. Herzenberg
2006-06-07T23:59:59.000Z
Recently, what appears to be a fundamental limit associated with the size of an object that separates the quantum behavior characterizing small objects from the classical behavior characterizing large objects has been derived from the Hubble velocity spread in an extended object. This threshold is now examined further and interpreted in terms of diffusion processes in stochastic quantum mechanics. This limiting size that separates quantum behavior from classical behavior is shown to correspond approximately to the diffusion distance of the object over the Hubble time.
AlGaN/GaN/AlN quantum-well field-effect transistors with highly resistive AlN epilayers
Jiang, Hongxing
AlGaN/GaN/AlN quantum-well field-effect transistors with highly resistive AlN epilayers Z. Y. Fana 66506-2601 Received 23 November 2005; accepted 5 January 2006; published online 16 February 2006 AlGaN/GaN/AlN quantum-well field-effect transistors have been demonstrated. By replacing a semi-insulating GaN epilayer
Impact of uniaxial strain on P-channel 111-V quantum-well field effect transistors
Xia, Ling, Ph. D. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
Continuous scaling of Si complementary metal-oxide-semiconductor (CMOS) technology requires a boost in carrier injection velocity. With the benefits of strained Si having been exhausted, n-channel I-V quantum-well field ...
The effect of surface conductance on lateral gated quantum devices in Si/SiGe heterostructures
Lin, Xi
Quantum dots in Si/SiGe heterostructures are expected to have relatively long electron spin decoherence times, because of the low density of nuclear spins and the weak coupling between nuclear and electron spins. We provide ...
Dynamics of quantum-classical hybrid systems: Effect of matter-wave pressure
Shen, J. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Huang, X. L. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Yi, X. X. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Centre for Quantum Technologies and Department of Physics, National University of Singapore, Singapore 117543 (Singapore); Wu Chunfeng; Oh, C. H. [Centre for Quantum Technologies and Department of Physics, National University of Singapore, Singapore 117543 (Singapore)
2010-12-15T23:59:59.000Z
Radiation pressure affects the kinetics of a system exposed to radiation and it constitutes the basis of laser cooling. In this article, we study matter-wave pressure through examining the dynamics of a quantum-classical hybrid system. The quantum and classical subsystems are affected mutually via a changing boundary condition. Two systems, that is, an atom and a Bose-Einstein condensate (BEC), are considered as the quantum subsystems, while an oscillating wall is taken as the classical subsystem. We show that the classical subsystem would experience a force proportional to Q{sup -3} from the quantum atom, where Q denotes the distance between the two walls, whereas it acquires an additional force proportional to Q{sup -2} from the BEC due to the atom-atom interaction in the BEC. These forces can be understood as the matter-wave pressure.
Quantum noise and radiation pressure effects in high power optical interferometers
Corbitt, Thomas Randall
2008-01-01T23:59:59.000Z
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 ...
Ye, Peng
2015-01-01T23:59:59.000Z
Topological quantum field theory (TQFT) plays a very important role in understanding topological phases of quantum matter. For example, Chern-Simons theory reveals the key mechanism of charge-flux attachment for fractional quantum hall effect (FQHE). It also completely describes all the essential topological data, e.g., fractionalized statistics, fractionalized charge of quasiparticles in FQHE sytems. Very recently, a new class of topological phases -- symmetry-protected topological (SPT) phases in interacting bosonic systems has been proposed based on the (extended) group cohomology theory. In two dimensions, it has been shown that bosonic SPT phases with Abelian symmetry can be well understood in terms of Chern-Simons theory. In this paper, we attempt to achieve a complete TQFT description for all bosonic SPT phases with Abelian group symmetry in three dimensions. The TQFT description reveals the key mechanism for three dimensional bosonic SPT phases in a simple and intuitive way.
Internal plasma potential measurements of a Hall thruster using plasma lens focusing
Linnell, Jesse A.; Gallimore, Alec D. [Plasmadynamics and Electric Propulsion Laboratory, Department of Aerospace Engineering, University of Michigan, 1919 Green Road, Room B107, Ann Arbor, Michigan 48109 (United States)
2006-10-15T23:59:59.000Z
Magnetic field topology has been found to be a central design concern for high-efficiency Hall thrusters. For future improvements in Hall thruster design, it is necessary to better understand the effects that magnetic field topology has on the internal plasma structure. The Plasmadynamics and Electric Propulsion Laboratory's High-speed Axial Reciprocating Probe system is used in conjunction with a floating emissive probe to map the internal plasma potential structure of the NASA-173Mv1 Hall thruster [R. R. Hofer, R. S. Jankovsky, and A. D. Gallimore, J. Propul. Power 22, 721 (2006); 22, 732 (2006)]. Measurements are taken at 300 and 500 V with a xenon propellant. Electron temperature and electric field are also measured and reported. The acceleration zone and equipotential lines are found to be strongly linked to the magnetic field lines. Moreover, in some cases the ions are accelerated strongly toward the center of the discharge channel. The agreement between magnetic field lines and equipotential lines is best for high-voltage operation. These results have strong implications on the performance and lifetime optimization of Hall thrusters.
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.
Rebuilding It Better: Greensburg, Kansas. City Hall (Brochure)
Not Available
2010-04-01T23:59:59.000Z
This document showcases the LEED-Platinum designed Greensburg City Hall, which was rebuilt green, after a massive tornado destroyed Greensburg, Kansas in May 2007.
Rebuilding It Better: Greensburg, Kansas, City Hall (Brochure)
Not Available
2010-09-01T23:59:59.000Z
This brochure details the energy efficient and sustainable aspects of the LEED Platinum-designated City Hall building in Greensburg, Kansas.
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...
Mario G. Silveirinha
2014-06-09T23:59:59.000Z
Here, we develop a comprehensive quantum theory for the phenomenon of quantum friction. Based on a theory of macroscopic quantum electrodynamics for unstable systems, we calculate the quantum expectation of the friction force, and link the friction effect to the emergence of system instabilities related to the Cherenkov effect. These instabilities may occur due to the hybridization of particular guided modes supported by the individual moving bodies, and selection rules for the interacting modes are derived. It is proven that the quantum friction effect can take place even when the interacting bodies are lossless and made of nondispersive dielectrics.
Schedule and cost estimate for an innovative Boston Harbor concert hall
Coste, Amelie, 1982-
2004-01-01T23:59:59.000Z
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 ...
Sadi, Toufik; Oksanen, Jani; Tulkki, Jukka [Department of Biomedical Engineering and Computational Sciences, Aalto University, P.O. Box 12200, FI-00076 Aalto (Finland)
2013-12-14T23:59:59.000Z
Recent experimental work has shown significant luminescence enhancement from near-surface quantum-well (QW) structures using metallic grating to convert surface plasmon (SP) modes into radiative modes. This work introduces a detailed theoretical study of plasmonic losses and the role of SPs in improving light extraction from grated light-emitting QW structures, using the fluctuational electrodynamics method. The method explains experimental results demonstrating emission enhancement, light scattering, and plasmonic coupling in the structures. We study these effects in angle-resolved reflectometry and luminescence setups in InGaN QW structures with silver grating. In contrast to experiments, our model allows direct calculation of the optical losses. The model predicts that the plasmonic coupling and scattering increases light emission by a factor of up to three compared to a flat semiconductor structure. This corresponds to reducing the absorption losses from approximately 93% in the ungrated metallic structure to 75% in the grated structure. Lower losses are associated with a significant emission enhancement enabled by the SPs of silver/GaN interfaces, which are present in the blue/green wavelength range, and can be optimized by carefully nanostructuring the metal layer and by the positioning of the QW. In general, the enhancement results from the interplay of mode scattering, conversion of SP energy directly into light, and losses in the metallic grating. The reported losses are very high when compared to the losses present in modern light-emitting diodes (LEDs). Albeit, our work provides tools needed for further optimization of plasmonic light extraction, eventually leading to highly efficient LEDs.
Valley pair qubits in double quantum dots of gapped graphene
G. Y. Wu; N. -Y. Lue; L. Chang
2011-07-03T23:59:59.000Z
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)).
Spin-Hall-assisted magnetic random access memory
Brink, A. van den, E-mail: a.v.d.brink@tue.nl; Swagten, H. J. M.; Koopmans, B. [Physics of Nanostructures, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)] [Physics of Nanostructures, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Cosemans, S.; Manfrini, M.; Van Roy, W.; Min, T. [imec, Kapeldreef 75, B-3001 Leuven (Belgium)] [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Cornelissen, S.; Vaysset, A. [imec, Kapeldreef 75, B-3001 Leuven (Belgium) [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Departement elektrotechniek (ESAT), KU Leuven, Kasteelpark Arenberg 10, B-3001 Heverlee (Belgium)
2014-01-06T23:59:59.000Z
We propose a write scheme for perpendicular spin-transfer torque magnetoresistive random-access memory that significantly reduces the required tunnel current density and write energy. A sub-nanosecond in-plane polarized spin current pulse is generated using the spin-Hall effect, disturbing the stable magnetic state. Subsequent switching using out-of-plane polarized spin current becomes highly efficient. Through evaluation of the Landau-Lifshitz-Gilbert equation, we quantitatively assess the viability of this write scheme for a wide range of system parameters. A typical example shows an eight-fold reduction in tunnel current density, corresponding to a fifty-fold reduction in write energy, while maintaining a 1?ns write time.
Quantum Evolution and Anticipation
Hans-Rudolf Thomann
2010-03-04T23:59:59.000Z
In a previous paper we have investigated quantum states evolving into mutually orthogonal states at equidistant times, and the quantum anticipation effect exhibited by measurements at one half step. Here we extend our analyzes of quantum anticipation to general type quantum evolutions and spectral measures and prove that quantum evolutions possessing an embedded orthogonal evolution are characterized by positive joint spectral measure. Furthermore, we categorize quantum evolution, assess anticipation strength and provide a framework of analytic tools and results, thus preparing for further investigation and experimental verification of anticipation in concrete physical situations such as the H-atom, which we have found to exhibit anticipation.
Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance Lucheng Chen
Andrews, Peter B.
Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance ......................................................................................................................... 2 2. Hamerschlag Hall Green Roof .............................................................................. 13 4. Methods of Storm Analysis and Green Roof Performance Analysis
Oshmyansky, A
2007-01-01T23:59:59.000Z
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 gr...
Alexander Oshmyansky
2007-03-08T23:59:59.000Z
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.
Quantum Effects on all Lagrangian Points and Prospects to Measure Them in the Earth-Moon System
Emmanuele Battista; Giampiero Esposito; Simone Dell' Agnello; Jules Simo
2015-06-16T23:59:59.000Z
The one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., both at the Lagrangian points of stable equilibrium and at those of unstable equilibrium the Newtonian values of planetoid's coordinates are changed by a few millimetres in the Earth-Moon system. First, we find that the equations governing the position of both noncollinear and collinear quantum libration points are algebraic fifth degree and ninth degree equations, respectively. 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. 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.
Hypernuclear spectroscopy program at JLab Hall C
Hashimoto, Osamu; Hashimoto, Osamu; Nakamura, Satoshi; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, O.; Baturin, Pavlo; Benmokhtar, Fatiha; Bosted, Peter; Carlini, Roger; Chen, X.; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, AJI; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Gueye, Paul; Halkyard, Rebekah; Honda, D.; Horn, Tanja; Hu, Bitao; Hu, S.; Hungerford, Ed; Ispiryan, Mikayel; Johnston, Kathleen; Jones, Mark; Kalantarians, Narbe; Kaneta, M.; Kato, F.; Kato, Seigo; Kawama, Daisuke; Keppel, Cynthia; Li, Ya; Luo, Wei; Mack, David; Margaryan, Amur; Marikyan, Gagik; Maruyama, Nayuta; Matsumura, Akihiko; Miyoshi, Toshinobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nomura, Hiroshi; Nonaka, Kenichi; Ohtani, Atsushi; Okayasu, Yuichi; Pamela, Priscilla; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Rodriguez, Victor; Sato, Yoshinori; Seva, Tomislav; Tang, Liguang; Simicevic, Neven; Smith, Gregory; Sumihama, Mizuki; Song, Y.; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tamura, Hirokazu; Tvaskis, Vladas; Vulcan, William; Wang, B.; Wells, Steven; Yan, Chen; Yuan, Lulin; Zamkochian, S.
2008-05-01T23:59:59.000Z
DOI: http://dx.doi.org/10.1016/j.nuclphysa.2008.01.029
Hypernuclear production by the (e,e?K+) reaction has unique advantages in hypernuclear spectroscopy of the S=?1 regime. The second-generation spectroscopy experiment on 12C, 7Li and 28Si targets has been recently carried out at JLab Hall C with a new experimental configuration (Tilt method) and also using a new high-resolution kaon spectrometer (HKS). The experiment is described and preliminary results are presented together with the empasis of significance of the (e,e?K+) reaction for ? hypernuclear spectroscopy and its future prospects.
Town Hall meeting | OpenEI Community
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Model checking quantum Markov chains
Yuan Feng; Nengkun Yu; Mingsheng Ying
2013-11-14T23:59:59.000Z
Although the security of quantum cryptography is provable based on the principles of quantum mechanics, it can be compromised by the flaws in the design of quantum protocols and the noise in their physical implementations. So, it is indispensable to develop techniques of verifying and debugging quantum cryptographic systems. Model-checking has proved to be effective in the verification of classical cryptographic protocols, but an essential difficulty arises when it is applied to quantum systems: the state space of a quantum system is always a continuum even when its dimension is finite. To overcome this difficulty, we introduce a novel notion of quantum Markov chain, specially suited to model quantum cryptographic protocols, in which quantum effects are entirely encoded into super-operators labelling transitions, leaving the location information (nodes) being classical. Then we define a quantum extension of probabilistic computation tree logic (PCTL) and develop a model-checking algorithm for quantum Markov chains.
Model checking quantum Markov chains
Feng, Yuan; Ying, Mingsheng
2012-01-01T23:59:59.000Z
Although the security of quantum cryptography is provable based on the principles of quantum mechanics, it can be compromised by the flaws in the design of quantum protocols and the noise in their physical implementations. So, it is indispensable to develop techniques of verifying and debugging quantum cryptographic systems. Model-checking has proved to be effective in the verification of classical cryptographic protocols, but an essential difficulty arises when it is applied to quantum systems: the state space of a quantum system is always a continuum even when its dimension is finite. To overcome this difficulty, we introduce a novel notion of quantum Markov chain, specially suited to model quantum cryptographic protocols, in which quantum effects are entirely encoded into super-operators labelling transitions, leaving the location information (nodes) being classical. Then we define a quantum extension of probabilistic computation tree logic (PCTL) and develop a model-checking algorithm for quantum Markov c...
An edition of Hall Caine's The Demon Lover
Linnstaedter, Joan
1993-01-01T23:59:59.000Z
Hall Caine, once a popular writer, is now forgotten. This is the first edition of Hall Caine's play The Demon Lover. The text is based on the only known typescript of the play which is corrected in the author's own hand and which was bound...
Low-frequency azimuthal stability analysis of Hall Diego Escobar
Carlos III de Madrid, Universidad
-neutral collision frequency w, we particle and energy wall-loss frequencies i energy loss per actual ionization i,e ion and electron cyclotron Larmor frequencies frequency of perturbation k azimuthal wave number and development of Hall thrusters. Nowadays, there are several companies manufacturing modern Hall thrusters
Pair spectrometer hodoscope for Hall D at Jefferson Lab
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Barbosa, Fernando J.; Hutton, Charles L.; Sitnikov, Alexandre; Somov, Alexander S.; Somov, S.; Tolstukhin, Ivan
2015-09-01T23:59:59.000Z
We present the design of the pair spectrometer hodoscope fabricated at Jefferson Lab and installed in the experimental Hall D. The hodoscope consists of thin scintillator tiles; the light from each tile is collected using wave-length shifting fibers and detected using a Hamamatsu silicon photomultiplier. Light collection was measured using relativistic electrons produced in the tagger area of the experimental Hall B.
University of Alberta Museums Curator Hall of Fame: Nomination Form
Machel, Hans
University of Alberta Museums Curator Hall of Fame: Nomination Form General Instructions: 1. Please someone other than the nominator 3. To be eligible for the University of Alberta Museums' Curator Hall of service in the role as Designated Curator of one of the registered University of Alberta Museums
RCP Spring 2011 SPONSORS MEETING PETROLEUM HALL, GREEN CENTER
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
Hamerschlag Hall Green Roof Project Water Monitoring System
Andrews, Peter B.
1 Hamerschlag Hall Green Roof Project Water Monitoring System Plans and Specifications Created By: David Carothers Date: 2/17/05 #12;2 Hamerschlag Hall Green Roof Project Date: 2/14/05 Created By: David and the flumes shall be water tight. (Figures 1&2) · The connection between the flume and the green roof membrane
Quantum Physics and Nanotechnology
Vladimir K. Nevolin
2011-06-06T23:59:59.000Z
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.
Photophysics of dopamine-modified quantum dots and effects on biological
Minarik, William
between a small molecule (the neurotransmitter dopamine) and CdSe/ZnS QDs. QDdopamine conjugates label that has been studied extensively for the creation of solar cells and optoelectronic devices (see ref. 1 established with CdSe and CdSe/ZnS quantum dots (QDs)35 , its application to living systems has not yet been
Shi, Y L; Wu, J X; Zhu, C J; Xu, J P; Yang, Y P
2015-01-01T23:59:59.000Z
We examine a Kerr phase gate in a semiconductor quantum well structure based on the tunnelling interference effect. We show that there exist a specific signal field detuning, at which the absorption/amplification of the probe field will be eliminated with the increase of the tunnelling interference. Simultaneously, the probe field will acquire a -\\pi phase shift at the exit of the medium. We demonstrate with numerical simulations that a complete 180^\\circ phase rotation for the probe field at the exit of the medium is achieved, which may result in many applications in information science and telecommunication.
Sinitsyn, NA; Hankiewicz, EM; Teizer, Winfried; Sinova, Jairo.
2004-01-01T23:59:59.000Z
new avenues in spintronics research and transport phenomena which may meet the first challenge. The intrinsic spin-Hall effect consists of a dissipationless spin-current contribution generated perpendicular to the driv- ing electric field whenever... that the dc z-component spin-current Hall response to a driv- ing internal electric field, jsz=sxyspinEy, in the clean limit has a universal value whenever the two Rashba split bands are occupied (the usual case), sxyspin=e /8p, and vanishes linearly...
Nonlinear friction in quantum mechanics
Roumen Tsekov
2013-03-10T23:59:59.000Z
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.
Wang, Zhi [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Jiang, Xiang-Wei; Li, Shu-Shen [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2014-03-24T23:59:59.000Z
We have presented a fully atomistic quantum mechanical simulation method on band-to-band tunneling (BTBT) field-effect transistors (FETs). Our simulation approach is based on the linear combination of bulk band method with empirical pseudopotentials, which is an atomist method beyond the effective-mass approximation or k.p perturbation method, and can be used to simulate real-size devices (?10{sup 5} atoms) efficiently (?5 h on a few computational cores). Using this approach, we studied the InAs dual-gate BTBT FETs. The I-V characteristics from our approach agree very well with the tight-binding non-equilibrium Green's function results, yet our method costs much less computationally. In addition, we have studied ways to increase the tunneling current and analyzed the effects of different mechanisms for that purpose.
Alessandro Sergi
2009-07-11T23:59:59.000Z
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.
Cylindrical Hall Thrusters with Permanent Magnets
Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.
2010-10-18T23:59:59.000Z
The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT. __________________________________________________
Undulator Hall Air Temperature Fault Scenarios
Sevilla, J.; Welch, J.; /SLAC; ,
2010-11-17T23:59:59.000Z
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.
Quantum Chaos & Quantum Computers
D. L. Shepelyansky
2000-06-15T23:59:59.000Z
The standard generic quantum computer model is studied analytically and numerically and the border for emergence of quantum chaos, induced by imperfections and residual inter-qubit couplings, is determined. This phenomenon appears in an isolated quantum computer without any external decoherence. The onset of quantum chaos leads to quantum computer hardware melting, strong quantum entropy growth and destruction of computer operability. The time scales for development of quantum chaos and ergodicity are determined. In spite the fact that this phenomenon is rather dangerous for quantum computing it is shown that the quantum chaos border for inter-qubit coupling is exponentially larger than the energy level spacing between quantum computer eigenstates and drops only linearly with the number of qubits n. As a result the ideal multi-qubit structure of the computer remains rather robust against imperfections. This opens a broad parameter region for a possible realization of quantum computer. The obtained results are related to the recent studies of quantum chaos in such many-body systems as nuclei, complex atoms and molecules, finite Fermi systems and quantum spin glass shards which are also reviewed in the paper.
Band filling effects on temperature performance of intermediate band quantum wire solar cells
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
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.
Effect of Monolayer Thickness Fluctuations on Coherent Exciton Coupling in Single Quantum Wells
Yuri D. Glinka; Zheng Sun; Mikhail Erementchouk; Michael N. Leuenberger; Alan D. Bristow; Steven T. Cundiff; Allan S. Bracker; Xiaoqin Li
2012-10-04T23:59:59.000Z
Monolayer fluctuations in the thickness of a semiconductor quantum well (QW) lead to three types of excitons, located in the narrower, average and thicker regions of the QW, which are clearly resolved in optical spectra. Whether or not these excitons are coherently coupled via Coulomb interactions is a long-standing debate. We demonstrate that different types of disorder in QWs distinctly affects the coherent coupling and that the coupling strength can be quantitatively measured using optical two-dimensional Fourier transform spectroscopy. We prove experimentally and theoretically that in narrow quantum wells the coherent coupling occurs predominantly between excitons residing in the disorder-free areas of the QWs and those residing in the plateau-type disorder. In contrast, excitons localized in the fault-type disorder potentials do not coherently couple to other excitons.
Effects of systematic phase errors on optimized quantum random-walk search algorithm
Yu-Chao Zhang; Wan-Su Bao; Xiang Wang; Xiang-Qun Fu
2015-01-09T23:59:59.000Z
This paper researches how the systematic errors in phase inversions affect the success rate and the number of iterations in optimized quantum random-walk search algorithm. Through geometric description of this algorithm, the model of the algorithm with phase errors is established and the relationship between the success rate of the algorithm, the database size, the number of iterations and the phase error is depicted. For a given sized database, we give both the maximum success rate of the algorithm and the required number of iterations when the algorithm is in the presence of phase errors. Through analysis and numerical simulations, it shows that optimized quantum random-walk search algorithm is more robust than Grover's algorithm.
Physics 5614 Spring 2005 Introduction to Quantum Electronics
Heflin, Randy
122 Robeson Hall Texts : Quantum Electronics, A. Yariv, 3rd ed. (will be given as hand-outs) Nonlinear Optics, R. W. Boyd Instructor : Prof. R. Heflin, Room 108A Robeson, ext. 1-4504 Office Hours : M 11 throughout the semester. Grades : 80% Homework 20% Research Paper (more details later) Chap. Title From Yariv
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
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.
Effects of time delay in feedback control of linear quantum systems
Kazunori Nishio; Kenji Kashima; Jun-ichi Imura
2008-11-27T23:59:59.000Z
We investigate feedback control of linear quantum systems subject to feedback-loop time delays. In particular, we examine the relation between the potentially achievable control performance and the time delays, and provide theoretical guidelines for the future experimental setup in two physical systems, which are typical in this research field. The evaluation criterion for the analysis is given by the optimal control performance formula, the derivation of which is from the classical control theoretic results about the input-output delay systems.
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
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.
Dry Dilution Refrigerator for Experiments on Quantum Effects in the Microwave Regime
Marx, A; Uhlig, K
2014-01-01T23:59:59.000Z
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...
Magnetic shielding of the channel walls in a Hall plasma accelerator
Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Grys, Kristi de; Mathers, Alex [Aerojet, Redmond, Washington 98052 (United States)
2011-03-15T23:59:59.000Z
In a qualification life test of a Hall thruster it was found that the erosion of the acceleration channel practically stopped after {approx}5600 h. Numerical simulations using a two-dimensional axisymmetric plasma solver with a magnetic field-aligned mesh reveal that when the channel receded from its early-in-life to its steady-state configuration the following changes occurred near the wall: (1) reduction of the electric field parallel to the wall that prohibited ions from acquiring significant impact kinetic energy before entering the sheath, (2) reduction of the potential fall in the sheath that further diminished the total energy ions gained before striking the material, and (3) reduction of the ion number density that decreased the flux of ions to the wall. All these changes, found to have been induced by the magnetic field, constituted collectively an effective shielding of the walls from any significant ion bombardment. Thus, we term this process in Hall thrusters 'magnetic shielding'.
Xavier Busch
2014-11-06T23:59:59.000Z
The two main predictions of quantum field theory in curved space-time, namely Hawking radiation and cosmological pair production, have not been directly tested and involve ultra high energy configurations. As a consequence, they should be considered with caution. Using the analogy with condensed matter systems, their analogue versions could be tested in the lab. Moreover, the high energy behavior of these systems is known and involves dispersion and dissipation, which regulate the theory at short distances. When considering experiments which aim to test the above predictions, there will also be a competition between the stimulated emission from thermal noise and the spontaneous emission out of vacuum. In order to measure these effects, one should thus compute the consequences of UV dispersion and dissipation, and identify observables able to establish that the spontaneous emission took place. In this thesis, we first analyze the effects of dispersion and dissipation on both Hawking radiation and pair particle production. To get explicit results, we work in the context of de Sitter space. Using the extended symmetries of the theory in such a background, exact results are obtained. These are then transposed to the context of black holes using the correspondence between de Sitter space and the black hole near horizon region. To introduce dissipation, we consider an exactly solvable model producing any decay rate. We also study the quantum entanglement of the particles so produced. In a second part, we consider explicit condensed matter systems, namely Bose Einstein condensates and exciton-polariton systems. We analyze the effects of dissipation on entanglement produced by the dynamical Casimir effect. As a final step, we study the entanglement of Hawking radiation in the presence of dispersion for a generic analogue system.
Raj Chakrabarti; Herschel Rabitz
2007-10-03T23:59:59.000Z
Numerous lines of experimental, numerical and analytical evidence indicate that it is surprisingly easy to locate optimal controls steering quantum dynamical systems to desired objectives. This has enabled the control of complex quantum systems despite the expense of solving the Schrodinger equation in simulations and the complicating effects of environmental decoherence in the laboratory. Recent work indicates that this simplicity originates in universal properties of the solution sets to quantum control problems that are fundamentally different from their classical counterparts. Here, we review studies that aim to systematically characterize these properties, enabling the classification of quantum control mechanisms and the design of globally efficient quantum control algorithms.
Scalable optical quantum computer
Manykin, E A; Mel'nichenko, E V [Institute for Superconductivity and Solid-State Physics, Russian Research Centre 'Kurchatov Institute', Moscow (Russian Federation)
2014-12-31T23:59:59.000Z
A way of designing a scalable optical quantum computer based on the photon echo effect is proposed. Individual rare earth ions Pr{sup 3+}, regularly located in the lattice of the orthosilicate (Y{sub 2}SiO{sub 5}) crystal, are suggested to be used as optical qubits. Operations with qubits are performed using coherent and incoherent laser pulses. The operation protocol includes both the method of measurement-based quantum computations and the technique of optical computations. Modern hybrid photon echo protocols, which provide a sufficient quantum efficiency when reading recorded states, are considered as most promising for quantum computations and communications. (quantum computer)
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
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.
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
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.
Buckled nano rod - a two state system: quantum effects on its dynamics
Aniruddha Chakraborty
2011-07-18T23:59:59.000Z
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.
Dynamics of Thermal Effects in the Spin-Wave Theory of Quantum Antiferromagnets
Ángel Rivas; Miguel A. Martin-Delgado
2013-01-17T23:59:59.000Z
We derive a master equation that allows us to study non-equilibrium dynamics of a quantum antiferromagnet. By resorting to spin-wave theory, we obtain a closed analytic form for the magnon decay rates. These turn out to be closely related to form factors, which are experimentally accessible by means of neutron and Raman scattering. Furthermore, we compute the time evolution of the staggered magnetization showing that, for moderate temperatures, the magnetic order is not spoiled even if the coupling is fully isotropic.
Sassoli de Bianchi, Massimiliano, E-mail: autoricerca@gmail.com
2013-09-15T23:59:59.000Z
In a letter to Born, Einstein wrote [42]: “Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the ‘old one.’ I, at any rate, am convinced that He does not throw dice.” In this paper we take seriously Einstein’s famous metaphor, and show that we can gain considerable insight into quantum mechanics by doing something as simple as rolling dice. More precisely, we show how to perform measurements on a single die, to create typical quantum interference effects, and how to connect (entangle) two identical dice, to maximally violate Bell’s inequality. -- Highlights: •Rolling a die is a quantum process admitting a Hilbert space representation. •Rolling experiments with a single die can produce interference effects. •Two connected dice can violate Bell’s inequality. •Correlations need to be created by the measurement, to violate Bell’s inequality.
Shepelyansky, Dima
in quantum computation, including the simula- tion of quantum chaos models showing rich and complex dynamics and image compression, signal process- ing, telecommunications and many other applications [1, 2]. Wavelets
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...
Hall viscosity and angular momentum in gapless holographic models
Liu, Hong
We use the holographic approach to compare the Hall viscosity ?[subscript H] and the angular momentum density J in gapless systems in 2 + 1 dimensions at finite temperature. We start with a conformal fixed point and turn ...
Theoretical and experimental investigation of Hall thruster miniaturization
Warner, Noah Zachary, 1978-
2007-01-01T23:59:59.000Z
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 ...
Replies to Weatherson, Hall, and Lange Michael Strevens
Strevens, Michael
; in what follows, I hope to show that Hall's and Lange's contributions as well amount not only to worthy of the outcomes of auctions of oil drilling rights in the Gulf of Mexico, provides a perfect illustration
University of California, Berkeley McLaughlin Hall
Alvarez-Cohen, Lisa
Procedures 7. Criminal or Violent Behavior 8. Explosion or Bomb Threat Procedures 9. Hazardous MaterialsLaughlin Hall BUILDING EMERGENCY PLAN As a building occupant, it is your responsibility to be familiar
Bigham, S.R.; Coffer, J.L. [Texas Christian Univ., Fort Worth, TX (United States)
1993-12-31T23:59:59.000Z
Cadmium sulfide semiconductor clusters in the quantum confined size regime (Q-CdS) may be successfully stabilized by double-stranded deoxyribonucleic acid (DNA) from calf thymus and E. Coli as well as by single-stranded ribonucleic acids (RNA) in the forms of Poly[A], Poly[C], Poly[G] and Poly [U]. These Q-CdS/ploynucleotide clusters exhibit broad trap emission characteristic of both cadmium and sulfur related defect sites at the semiconductor surface. Here the paper discusses differences in the nature of the stabilizer-cluster interaction between single-stranded and double-stranded polynucleotides, as probed by monitoring changes in photoluminescence after thermolysis or ferrocyanide addition. Thermolysis of Q-CdS/polynucleotide samples affects the interfacial interaction between cluster and stabilizer as demonstrated by a shift in the emission maximum and a change in quantum yield. Stern-Volmer analysis of photoluminescence quenching with ferrocyanide anions exhibits nonlinear behavior. Ferrocyanide anions quench the photoluminescene of Q-CdS/DNA approximately 38% more efficiently (in terms of integrated intensity) than Q-CdS/RNA after 0.17 mN addition. Such behavior suggests that single-stranded polynucleotides are better than double-stranded polynucleotides in terms of protecting the semiconductor surface from the highly negatively charged ferrocyanide anion.
Superradiant Quantum Heat Engine
Ali Ü. C. Hardal; Özgür E. Müstecapl?oglu
2015-04-22T23:59:59.000Z
Quantum physics revolutionized classical disciplines of mechanics, statistical physics, and electrodynamics. One branch of scientific knowledge however seems untouched: thermodynamics. Major motivation behind thermodynamics is to develop efficient heat engines. Technology has a trend to miniaturize engines, reaching to quantum regimes. Development of quantum heat engines (QHEs) requires emerging field of quantum thermodynamics. Studies of QHEs debate whether quantum coherence can be used as a resource. We explore an alternative where it can function as an effective catalyst. We propose a QHE which consists of a photon gas inside an optical cavity as the working fluid and quantum coherent atomic clusters as the fuel. Utilizing the superradiance, where a cluster can radiate quadratically faster than a single atom, we show that the work output becomes proportional to the square of the number of the atoms. In addition to practical value of cranking up QHE, our result is a fundamental difference of a quantum fuel from its classical counterpart.
Superradiant Quantum Heat Engine
Ali Ü. C. Hardal; Özgür E. Müstecapl?oglu
2015-07-16T23:59:59.000Z
Quantum physics revolutionized classical disciplines of mechanics, statistical physics, and electrodynamics. One branch of scientific knowledge however seems untouched: thermodynamics. Major motivation behind thermodynamics is to develop efficient heat engines. Technology has a trend to miniaturize engines, reaching to quantum regimes. Development of quantum heat engines (QHEs) requires emerging field of quantum thermodynamics. Studies of QHEs debate whether quantum coherence can be used as a resource. We explore an alternative where it can function as an effective catalyst. We propose a QHE which consists of a photon gas inside an optical cavity as the working fluid and quantum coherent atomic clusters as the fuel. Utilizing the superradiance, where a cluster can radiate quadratically faster than a single atom, we show that the work output becomes proportional to the square of the number of the atoms. In addition to practical value of cranking up QHE, our result is a fundamental difference of a quantum fuel from its classical counterpart.
Observation of chiral edge states with neutral fermions in synthetic Hall ribbons
Mancini, M; Cappellini, G; Livi, L; Rider, M; Catani, J; Sias, C; Zoller, P; Inguscio, M; Dalmonte, M; Fallani, L
2015-01-01T23:59:59.000Z
Chiral edge states are a hallmark of quantum Hall physics. In electronic systems, they appear as a macroscopic consequence of the cyclotron orbits induced by a magnetic field, which are naturally truncated at the physical boundary of the sample. Here we report on the experimental realization of chiral edge states in a ribbon geometry with an ultracold gas of neutral fermions subjected to an artificial gauge field. By imaging individual sites along a synthetic dimension, we detect the existence of the edge states, investigate the onset of chirality as a function of the bulk-edge coupling, and observe the edge-cyclotron orbits induced during a quench dynamics. The realization of fermionic chiral edge states is a fundamental achievement, which opens the door towards experiments including edge state interferometry and the study of non-Abelian anyons in atomic systems.
Observation of chiral edge states with neutral fermions in synthetic Hall ribbons
M. Mancini; G. Pagano; G. Cappellini; L. Livi; M. Rider; J. Catani; C. Sias; P. Zoller; M. Inguscio; M. Dalmonte; L. Fallani
2015-02-09T23:59:59.000Z
Chiral edge states are a hallmark of quantum Hall physics. In electronic systems, they appear as a macroscopic consequence of the cyclotron orbits induced by a magnetic field, which are naturally truncated at the physical boundary of the sample. Here we report on the experimental realization of chiral edge states in a ribbon geometry with an ultracold gas of neutral fermions subjected to an artificial gauge field. By imaging individual sites along a synthetic dimension, we detect the existence of the edge states, investigate the onset of chirality as a function of the bulk-edge coupling, and observe the edge-cyclotron orbits induced during a quench dynamics. The realization of fermionic chiral edge states is a fundamental achievement, which opens the door towards experiments including edge state interferometry and the study of non-Abelian anyons in atomic systems.
Wetzel, Christian M.
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 55, NO. 6, DECEMBER 2008 3633 Radiation Effects on In to 500 keV alpha particles to fluences above 1014 cm2 to probe the relative radiation tolerance that the quantum well luminescence decay rate is dom- inated by radiation-induced defects in the GaN epilayer. In
Finkelstein, Gleb
stays p-type "leads" . Therefore, a quantum dot is formed within a nanotube, de- fined by p-n and n-p junctions. As a result, a Coulomb blockade sets in at low temperatures Fig. 1 . Figure 1 shows conductance-n junction transparency grows with Vgate, resulting in an enhancement of the Kondo effect in each successive
Chu, Shih-I
986 IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 13, NO. 2, JUNE 2003 Effects of Pulse for conventional computers. Among the many approaches, building quantum computers with the use of superconducting up. Furthermore, superconducting qubits can be driven by pulsed microwaves to perform various 1-bit
Effect of polarization on intersubband transition in AlGaN/GaN multiple quantum wells
Chen, G.; Li, Z. L.; Wang, X. Q.; Huang, C. C.; Rong, X.; Xu, F. J.; Tang, N.; Qin, Z. X.; Shen, B. [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)] [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Sang, L. W.; Sumiya, M. [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)] [Optical and Electronic Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Chen, Y. H. [Laboratory of Semiconductor Material Science, Institute of Semiconductors, CAS, Beijing 100083 (China)] [Laboratory of Semiconductor Material Science, Institute of Semiconductors, CAS, Beijing 100083 (China); Ge, W. K. [Department of Physics, Tsinghua University, Beijing 100871 (China)] [Department of Physics, Tsinghua University, Beijing 100871 (China)
2013-05-13T23:59:59.000Z
Intersubband transitions (ISBT) of AlGaN/GaN multiple quantum wells (MQWs) with wavelength towards atmospheric window (3-5 {mu}m) have been investigated. A Ga-excess epitaxial method is used in the molecular beam epitaxy leading to ultra-sharp interface and negligible elements inter-diffusion. The absorption peak wavelength of the ISBT was successfully tuned in the range of 3-4 {mu}m by modifying the GaN well thickness from 2.8 to 5.5 nm. It was further found that the polarization charge density of the AlGaN/GaN MQWs was about -0.034 C/m{sup 2} which gave rise to blueshift of the ISBT wavelength and thus partially compensated its redshift with increasing well thickness.
Alfredo Iorio; Gaetano Lambiase
2014-12-15T23:59:59.000Z
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.
QUANTUM CHAOS IN QUANTUM NETWORKS()
Shepelyansky, Dima
QUANTUM CHAOS IN QUANTUM NETWORKS() Chepelianskii Alexei LycÂ´ee Pierre de Fermat and Quantware MIPS Computers and Quantum Chaos", June 28 - 30, 2001, Villa Olmo, Como, Italy #12;SHORT DESCRIPTION OF THE RESULTS Quantum chaos in a quantum small world We introduce and study a quantum small world model
Quantum Chaos1 The term Quantum Chaos designates a body of knowledge which has been estab-
Weigert, Stefan
Quantum Chaos1 The term Quantum Chaos designates a body of knowledge which has been estab- lished unreliable if not effectively impossible. A considerable amount of studies relevant to Quantum Chaos revolve
Jeans instability in a quantum dusty magnetoplasma
Salimullah, M. [Department of Physics, GC University, Lahore-54000 (Pakistan); Salam Chair in Physics, GC University, Lahore-54000 (Pakistan); Jamil, M.; Shah, H. A. [Department of Physics, GC University, Lahore-54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, GC University, Lahore-54000 (Pakistan)
2009-01-15T23:59:59.000Z
Jeans instability in a homogeneous cold quantum dusty plasma in the presence of the ambient magnetic field and the quantum effect arising through the Bohm potential has been examined using the quantum magnetohydrodynamic model. It is found that the Jeans instability is significantly reduced by the presence of the dust-lower-hybrid wave and the ion quantum effect. The minimum wavenumber for Jeans stability depends clearly on ion quantum effect and the dust-lower-hybrid frequency also.
John Ashmead
2010-05-05T23:59:59.000Z
Normally we quantize along the space dimensions but treat time classically. But from relativity we expect a high level of symmetry between time and space. What happens if we quantize time using the same rules we use to quantize space? To do this, we generalize the paths in the Feynman path integral to include paths that vary in time as well as in space. We use Morlet wavelet decomposition to ensure convergence and normalization of the path integrals. We derive the Schr\\"odinger equation in four dimensions from the short time limit of the path integral expression. We verify that we recover standard quantum theory in the non-relativistic, semi-classical, and long time limits. Quantum time is an experiment factory: most foundational experiments in quantum mechanics can be modified in a way that makes them tests of quantum time. We look at single and double slits in time, scattering by time-varying electric and magnetic fields, and the Aharonov-Bohm effect in time.
J. M. Robbins
2010-09-10T23:59:59.000Z
Quantum eigenstates undergoing cyclic changes acquire a phase factor of geometric origin. This phase, known as the Berry phase, or the geometric phase, has found applications in a wide range of disciplines throughout physics, including atomic and molecular physics, condensed matter physics, optics, and classical dynamics. In this article, the basic theory of the geometric phase is presented along with a number of representative applications. The article begins with an account of the geometric phase for cyclic adiabatic evolutions. An elementary derivation is given along with a worked example for two-state systems. The implications of time-reversal are explained, as is the fundamental connection between the geometric phase and energy level degeneracies. We also discuss methods of experimental observation. A brief account is given of geometric magnetism; this is a Lorenz-like force of geometric origin which appears in the dynamics of slow systems coupled to fast ones. A number of theoretical developments of the geometric phase are presented. These include an informal discussion of fibre bundles, and generalizations of the geometric phase to degenerate eigenstates (the nonabelian case) and to nonadiabatic evolution. There follows an account of applications. Manifestations in classical physics include the Hannay angle and kinematic geometric phases. Applications in optics concern polarization dynamics, including the theory and observation of Pancharatnam's phase. Applications in molecular physics include the molecular Aharonov-Bohm effect and nuclear magnetic resonance studies. In condensed matter physics, we discuss the role of the geometric phase in the theory of the quantum Hall effect.
TRINITY HALL TRINITY LANE CAMBRIDGE CB2 1TJ conference@trinhall.cam.ac.uk 01223 764444
Lasenby, Joan
TRINITY HALL TRINITY LANE CAMBRIDGE CB2 1TJ conference@trinhall.cam.ac.uk 01223 764444 TRINITY HALL, minerally too with subtle nutty oak on a long finish. 1 #12;TRINITY HALL TRINITY LANE CAMBRIDGE CB2 1TJ
Tao, X. D.; Feng, Z.; Miao, B. F.; Sun, L.; You, B.; Wu, D.; Du, J.; Zhang, W.; Ding, H. F., E-mail: hfding@nju.edu.cn [Department of Physics, National Laboratory of Solid State Microstructures, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)
2014-05-07T23:59:59.000Z
We present the experimental study of the spin Hall angle (SHA) and spin diffusion length of Pd with the spin pumping and microwave photoresistance effects. The Py/Pd bilayer stripes are excited with an out-of-plane microwave magnetic field. The pure spin current is thus pumped and transforms into charge current via the inverse spin Hall effect (ISHE) in Pd layer, yielding an ISHE voltage. The ISHE voltage can be distinguished from the unwanted signal caused by the anisotropic magnetoresistance according to their different symmetries. Together with Pd thickness dependent measurements of in and out-of-plane precessing angles and effective spin mixing conductance, the SHA and spin-diffusion length of Pd are quantified as 0.0056?±?0.0007 and 7.3?±?0.7?nm, respectively.
Magnetic shielding of Hall thrusters at high discharge voltages
Mikellides, Ioannis G., E-mail: Ioannis.G.Mikellides@jpl.nasa.gov; Hofer, Richard R.; Katz, Ira; Goebel, Dan M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
2014-08-07T23:59:59.000Z
A series of numerical simulations and experiments have been performed to assess the effectiveness of magnetic shielding in a Hall thruster operating in the discharge voltage range of 300–700?V (I{sub sp}???2000–2700?s) at 6?kW, and 800?V (I{sub sp} ? 3000) at 9?kW. At 6?kW, the magnetic field topology with which highly effective magnetic shielding was previously demonstrated at 300?V has been retained for all other discharge voltages; only the magnitude of the field has been changed to achieve optimum thruster performance. It is found that magnetic shielding remains highly effective for all discharge voltages studied. This is because the channel is long enough to allow hot electrons near the channel exit to cool significantly upon reaching the anode. Thus, despite the rise of the maximum electron temperature in the channel with discharge voltage, the electrons along the grazing lines of force remain cold enough to eliminate or reduce significantly parallel gradients of the plasma potential near the walls. Computed maximum erosion rates in the range of 300–700?V are found not to exceed 10{sup ?2}?mm/kh. Such rates are ?3 orders of magnitude less than those observed in the unshielded version of the same thruster at 300?V. At 9?kW and 800?V, saturation of the magnetic circuit did not allow for precisely the same magnetic shielding topology as that employed during the 6-kW operation since this thruster was not designed to operate at this condition. Consequently, the maximum erosion rate at the inner wall is found to be ?1 order of magnitude higher (?10{sup ?1}?mm/kh) than that at 6?kW. At the outer wall, the ion energy is found to be below the sputtering yield threshold so no measurable erosion is expected.