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Condensed Matter papers — page 143

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Delocalized Coulomb phase in two dimensions
Extending finite size scaling theory to the many body ground state, one finds that Coulomb repulsion can drive a system of spinless fermions in a random potential from the Anderson insulator (Fermi…
Xavier Waintal, Giuliano Benenti, Jean-Louis PichardJun 25, 1999
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Glasses: a new view from QED coherence
Faced with the Kauzmann paradox, glasses have always been a puzzle for condensed matter theorists. We show that in a new picture of condensed matter, which takes into account the coherent interaction…
E. Del Giudice, G. Preparata, M. BuzzacchiJun 25, 1999
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Direct exchange in the edge-sharing spin-1/2 compound MgVO3
Bandstructure calculations with different spin arrangement for the spin-chain compound MgVO3 have been performed, and paramagnetic as well as magnetic solutions with ferro- and antiferromagnetically…
I. Chaplygin, R. Hayn, K. KoepernikJun 25, 1999
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Quantum opening of the Coulomb gap in two dimensions
For a constant density of spinless fermions in strongly disordered two dimensional clusters, the energy level spacing between the ground state and the first excitation is studied for increasing…
Giuliano Benenti, Xavier Waintal, Jean-Louis Pichard et al.Jun 25, 1999
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Finite Temperature Behavior of the ν=1 Quantum Hall Effect in Bilayer Electron Systems
An effective field theoretic description of ν=1 bilayer electron systems stabilized by Coulomb repulsion in a single wide quantum well is examined using renormalization group techniques. The system…
M. Abolfath, Ramin Golestanian, T. JungwirthJun 24, 1999
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Coherent dynamics of Bose-Einstein condensates in high-finesse optical cavities
We study the mutual interaction of a Bose-Einstein condensed gas with a single mode of a high-finesse optical cavity. We show how the cavity transmission reflects condensate properties and calculate…
Peter Horak, Stephen M. Barnett, Helmut RitschJun 24, 1999
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Van Hove Singularity and Superconductivity in Disordered Sr2RuO4
On the basis of a simple model we analyse the influence of disorder on critical temperature TC in p-wave superconductors. The disorder is treated by means of the Coherent Potential Approximation…
G. Litak, J. F. Annett, B. L. GyorffyJun 24, 1999
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Third-order phase transition and superconductivity in thin films
We have found a new mean field solution in the BCS theory of superconductivity. This unconventional solution indicates the existence of superconducting phase transitions of third order in thin films,…
Christofer Cronstrom, Milan NogaJun 24, 1999
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Critical Exponents without beta-Function
We point out that the recently developed strong-coupling theory enables us to calculate the three main critical exponents nu, eta, omega, from the knowledge of only the two renormalization constants…
Hagen KleinertJun 24, 1999
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Femtosecond Coherent Dynamics of the Fermi Edge Singularity and Exciton Hybrid
We study theoretically the coherent nonlinear optical response of doped semiconductors with partially occupied subbands. When the Fermi energy of an occupied subband approaches the exciton level of…
T. V. Shahbazyan, N. Primozich, I. E. Perakis et al.Jun 23, 1999
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Apparent multifractality in financial time series
We present a exactly soluble model for financial time series that mimics the long range volatility correlations known to be present in financial data. Although our model is `monofractal' by…
Jean-Philippe Bouchaud, Marc Potters, Martin MeyerJun 23, 1999
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Surface versus crystal-termination effects in the optical properties of surfaces
We prove, by realistic microscopic calculations within the sp3s* Tight Binding method for GaAs (110) and (100), that the surface optical properties are not influenced by long-range crystal…
Rodolfo Del Sole, Giovanni OnidaJun 23, 1999
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Effects of temperature upon the collapse of a Bose-Einstein condensate in a gas with attractive interactions
We present a study of the effects of temperature upon the excitation frequencies of a Bose-Einstein condensate formed within a dilute gas with a weak attractive effective interaction between the…
M. J. Davis, D. A. W. Hutchinson, E. ZarembaJun 22, 1999
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Phase Transition in the Two-Dimensional Gauge Glass
The two-dimensional XY gauge glass, which describes disordered superconducting grains in strong magnetic fields, is investigated, with regard to the possibility of a glass transition. We compute the…
M. Y. Choi, Sung Yong ParkJun 22, 1999
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Exact Eigenstates and Magnetic Response of Spin-1 and Spin-2 Vectorial Bose-Einstein Condensates
The exact eigenspectra and eigenstates of spin-1 and spin-2 vectorial Bose-Einstein condensates (BECs) are found, and their response to a weak magnetic field is studied and compared with their…
Masato Koashi, Masahito UedaJun 21, 1999
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Optimal orbitals from energy fluctuations in correlated wave functions
A quantum Monte Carlo method of determining Jastrow-Slater wave functions for which the energy is stationary with respect to variations in the single-particle orbitals is presented. A potential is…
Stephen Fahy, Claudia FilippiJun 19, 1999
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Two-dimensional pattern formation in surfactant-mediated epitaxial growth
The effects of a surfactant on two-dimensional pattern formation in epitaxial growth are explored theoretically using a simple model, in which an adatom becomes immobile only after overcoming a large…
Bang-Gui Liu, Jing Wu, E. G. Wang et al.Jun 19, 1999
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First-Order Phase Transition in a Quantum Hall Ferromagnet
The single-particle energy spectrum of a two-dimensional electron gas in a perpendicular magnetic field consists of equally-spaced spin-split Landau levels, whose degeneracy is proportional to the…
Vincenzo Piazza, Vittorio Pellegrini, Fabio Beltram et al.Jun 18, 1999
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Fidelity and leakage of Josephson qubits
The unit of quantum information is the qubit, a vector in a two-dimensional Hilbert space. On the other hand, quantum hardware often operates in two-dimensional subspaces of vector spaces of higher…
Rosario Fazio, G. Massimo Palma, Jens SiewertJun 18, 1999
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Watching a superfluid untwist itself: Recurrence of Rabi oscillations in a Bose-Einstein condensate
The order parameter of a condensate with two internal states can continuously distort in such a way as to remove twists that have been imposed along its length. We observe this effect experimentally…
M. R. Matthews, B. P. Anderson, P. C. Haljan et al.Jun 17, 1999
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On the time evolution of the entropic index
We adapt the Kolmogorov-Sinai entropy to the non-extensive perspective recently advocated by Tsallis. The resulting expression is an average on the invariant distribution, which should be used to…
Jin Yang, Paolo GrigoliniJun 17, 1999
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Fast-Convergent Resummation Algorithm and Critical Exponents of phi4-Theory in Three Dimensions
We develop an efficient algorithm for evaluating divergent perturbation expansions of field theories in the bare coupling constant gB for which we possess a finite number L of expansion coefficients…
Florian Jasch, Hagen KleinertJun 16, 1999
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Effective Linear Two-Body Method for Many-Body Problems
This paper reports a detailed description of the equivalent linear two-body method for the many body problem, which is based on an approximate reduction of the many-body Schroedinger equation by the…
Yeong E. Kim, Alexander L. ZubarevJun 16, 1999
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Perturbation Theory for Particle in a Box
Recently developed strong-coupling theory open up the possibility of treating quantum-mechanical systems with hard-wall potentials via perturbation theory. To test the power of this theory we study…
H. Kleinert, A. Chervyakov, B. HamprechtJun 16, 1999
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Examination of self interaction correction methods for Na clusters
We examine whether the self interaction correction method by Harrison, which does not introduce the spherical single particle density approximation to energy functional, can be applied to Na…
K. Yoshizaki, A. Ono, N. TakigawaJun 16, 1999
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