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Condensed Matter papers — page 224

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Excitation spectroscopy of vortex states in dilute Bose-condensed gases
We apply linear-response analysis to the Gross-Pitaevskii equation to obtain the excitation frequencies of a Bose-Einstein condensate in a vortex state, and apply it to a system of Rubidium atoms…
R. J. Dodd, K. Burnett, Mark Edwards et al.Oct 10, 1996
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Low-Lying Excited States and Low-Temperature Properties of an Alternating Spin-1 / Spin-1/2 Chain : A DMRG study
We report spin wave and DMRG studies of the ground and low-lying excited states of uniform and dimerized alternating spin chains. The DMRG procedure is also employed to obtain low-temperature…
Swapan K. Pati, S. Ramasesha, Diptiman SenOct 8, 1996
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Role of divergence of classical trajectories in quantum chaos
We study logarithmical in effects in the statistical description of quantum chaos. We found analytical expressions for the deviations from the universality in the weak localization…
I. L. Aleiner, A. I. LarkinOct 6, 1996
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Are Steadily Moving Crystals Unstable?
We study the dynamics of small fluctuations about the uniform state of a crystal moving through a dissipative medium, e.g. a sedimenting colloidal crystal or a moving flux lattice, using a set of…
Rangan Lahiri, Sriram RamaswamyOct 2, 1996
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Non-magnetic impurities in S=1/2 spin-Peierls system and Heisenberg ladder systems
In this paper we study the effect of non-magnetic impurities in spin-Peierls system CuGeO3 within the framework of non-linear sigma model plus topological term. We show that local moments are…
Tai-Kai NgOct 2, 1996
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Quantum-critical scaling and temperature-dependent logarithmic corrections in the spin-half Heisenberg chain
Low temperature dynamics of the S=1/2 Heisenberg chain is studied via a simple ansatz generalizing the conformal mapping and analytic continuation procedures to correlation functions with…
O. A. Starykh, R. R. P. Singh, A. W. SandvikOct 2, 1996
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Bose-Einstein Condensation in a Harmonic Potential
We examine several features of Bose-Einstein condensation (BEC) in an external harmonic potential well. In the thermodynamic limit, there is a phase transition to a spatial Bose-Einstein condensed…
W. J. MullinOct 1, 1996
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Angular Dependences of Third Harmonic Generation from Microdroplets
We present experimental and theoretical results for the angular dependence of third harmonic generation (THG) of water droplets in the micrometer range (size parameter 62<ka<248). The THG signal in…
J. Kasparian, B. Krämer, J. P. Dewitz et al.Oct 1, 1996
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Complete Pseudoparticle Representation and the Conductivity Spectrum of the Hubbard Chain
We use a complete pseudoparticle operator representation to study the explicit form of the finite-frequency conductivity for the Hubbard chain. Our study reveals that the spectral weight is mostly…
J. M. P. Carmelo, N. M. R. Peres, D. K. CampbellSep 30, 1996
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Turbulence and finance?
Analogies between the price dynamics in the foreign exchange market and 3-dimensional fully developed turbulence were recently presented in Nature vol. 381, 767-769 (1996). Independently, we have…
Rosario N. Mantegna, H. Eugene StanleySep 30, 1996
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Pearling and Pinching: Propagation of Rayleigh Instabilities
A new category of front propagation problems is proposed in which a spreading instability evolves through a singular configuration before saturating. We examine the nature of this front for the…
Thomas R. Powers, Raymond E. GoldsteinSep 30, 1996
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Crossover from Isotropic to Directed Percolation
Directed percolation is one of the generic universality classes for dynamic processes. We study the crossover from isotropic to directed percolation by representing the combined problem as a random…
Per Frojdh, Marcel den NijsSep 30, 1996
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Conductivity in a symmetry broken phase: Spinless fermions with 1/d corrections
The dynamic conductivity σ(ω) of strongly correlated electrons in a symmetry broken phase is investigated in the present work. The model considered consists of spinless fermions with repulsive…
Goetz S. UhrigSep 30, 1996
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Hall effect of charge carriers in a correlated system
The dynamical Hall response in a correlated electronic system is analysed within the linear response theory for tight binding models. At T=0 the d.c. Hall constant for a single quasiparticle is…
Peter PrelovsekSep 30, 1996
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Numerical results for generalized RVB wavefunctions
Numerical results are presented for a generalized resonance valence bond state which includes both ionic and covalent contributions in each bond ; non nearest-neighbor bonds are also considered.…
G. Fano, F. Ortolani, L. ZiosiSep 30, 1996
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No End of Tricks: Electrons in the Fractional Quantum Hall Regime
In the strong magnetic field fractional quantum Hall regime, electrons in a two-dimensional electron system are confined to their lowest Landau level. Because of the macroscopic Landau level…
A. H. MacDonaldSep 30, 1996
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Atomic Self-Diffusion in Quasicrystals: A Molecular Dynamics Study
We present a molecular dynamics study on atomic self-diffusion in Frank-Kasper type dodecagonal quasicrystals. It is found that the quasicrystal-specific flip mechanism for atomic diffusion as…
Johannes Roth, Franz GaehlerSep 30, 1996
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A new binary decagonal Frank-Kasper quasicrystal phase
A structure model of atoms of two sizes, interacting with Lennard-Jones potentials and simulated by molecular dynamics, was observed to freeze into a decagonal quasicrystal dominated by Frank-Kasper…
Johannes Roth, Christopher L. HenleySep 30, 1996
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``Splitting'' of Delocalized States in a Double--Layer System in a Strong Magnetic Field
A double--layer system in a strong perpendicular magnetic field is considered. We assume a random potential in each layer to be smooth. We also assume that there is no correlation between random…
A. Gramada, M. E. RaikhSep 30, 1996
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Continuous Quantum Phase Transitions
A quantum system can undergo a continuous phase transition at the absolute zero of temperature as some parameter entering its Hamiltonian is varied. These transitions are particularly interesting…
S. L. Sondhi, S. M. Girvin, J. P. Carini et al.Sep 29, 1996
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Computer Simulations of Quantum Chains
We report recent progress in computer simulations of quantum systems described in the path-integral formulation. For the example of the ϕ4 quantum chain we show that the accuracy of the simulation…
Wolfhard Janke, Tilman SauerSep 29, 1996
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Glass Formation in the Gay-Berne Nematic Liquid Crystal
We present the results of molecular dynamics simulations of the Gay-Berne model of liquid crystals, supercooled from the nematic phase. We find a glass transition to a metastable phase with nematic…
A. M. Smondyrev, Robert A. PelcovitsSep 28, 1996
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Multifractal analysis of the metal-insulator transition in anisotropic systems
We study the Anderson model of localization with anisotropic hopping in three dimensions for weakly coupled chains and weakly coupled planes. The eigenstates of the Hamiltonian, as computed by…
Frank Milde, Rudolf A. Römer, Michael SchreiberSep 28, 1996
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Condensation in the Backgammon model
We analyse the properties of a very simple ``balls-in-boxes'' model which can exhibit a phase transition between a fluid and a condensed phase, similar to behaviour encountered in models of…
P. Bialas, Z. Burda, D. JohnstonSep 27, 1996
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Evaluation of the BCS Approximation for the Attractive Hubbard Model in One Dimension
The ground state energy and energy gap to the first excited state are calculated for the attractive Hubbard model in one dimension using both the Bethe Ansatz equations and the variational BCS…
F. MarsiglioSep 27, 1996
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