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Condensed Matter papers — page 58

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Theory of Open Quantum Systems as Applied to Spin Relaxation in Solids
We employ the method of the theory of open quantum systems to analyze spin relaxation and decoherence in semiconductors in the presence of a magnetic field. We derive a set of Bloch equations for…
Vadim I. Puller, Lev G. Mourokh, Norman J. M. Horing et al.May 29, 2002
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Influence of nonstoichiometry and iron doping on optical absorption in KNbO3 single crystal
Single crystals of KNbO3 and KNbO3 : Fe have been grown using the flux method at various technological conditions. The investigations of optical absorption of these crystals were carried out. Marked…
M. Milata, K. Wojcik, K. ZieleniecMay 29, 2002
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Efficiency of Scale-Free Networks: Error and Attack Tolerance
The concept of network efficiency, recently proposed to characterize the properties of small-world networks, is here used to study the effects of errors and attacks on scale-free networks. Two…
Paolo Crucitti, Vito Latora, Massimo Marchiori et al.May 28, 2002
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Decay of superfluid turbulence via Kelvin wave radiation and vortex reconnections
The elementary processes involved in the decay of superfluid turbulence in the limit of low temperature are studied by numerical simulations of vortex ring collisions. We find that small vortex rings…
M. Leadbeater, D. C. Samuels, C. F. Barenghi et al.May 28, 2002
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Magnetic properties of alpha-iron(II) phthalocyanine
We report on the magnetic properties of the supra-molecular compound iron(II) phthalocyanine in its alpha-form. dc- and ac-susceptometry measurements and Mossbauer experiments show that the iron…
M. Evangelisti, J. Bartolome, L. J. de Jongh et al.May 28, 2002
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Superfluidity in Dilute Trapped Bose Gases
A commonly used theoretical definition of superfluidity in the ground state of a Bose gas is based on the response of the system to an imposed velocity field or, equivalently, to twisted boundary…
Elliott H. Lieb, Robert Seiringer, Jakob YngvasonMay 27, 2002
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On the unitarity of S-matrix in 1-d case
It is shown that the scattering S-matrix is unitary even if the scattering potential U(x) tends to different limits at plus and minus infinity. This result is in contrast to the statements of some…
Dimitar I. PushkarovMay 27, 2002
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Probing Multi-Scale Energy Landscapes Using the String Method
A novel and powerful method is presented for the study of rare switching events in complex systems with multiscale energy landscapes. The method performs an umbrella sampling of the equilibrium…
Weinan E, Weiqing Ren, Eric Vanden-EijndenMay 25, 2002
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String Method for the Study of Rare Events
We present a new and efficient method for computing the transition pathways, free energy barriers, and transition rates in complex systems with relatively smooth energy landscapes. The method…
Weinan E, Weiqing Ren, Eric Vanden-EijndenMay 25, 2002
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1D model for the dynamics and expansion of elongated Bose-Einstein condensates
We present a 1D effective model for the evolution of a cigar-shaped Bose-Einstein condensate in time dependent potentials whose radial component is harmonic. We apply this model to investigate the…
Pietro Massignan, Michele ModugnoMay 24, 2002
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Design of Adiabatic Logic for a Quantum CNOT Gate
We examine the realization of a quantum CNOT gate by adiabatic operations.The principles of such systems and their analysis are briefly discussed and a model consisting of two weakly coupled double-…
V. Corato, P. Silvestrini, L. Stodolsky et al.May 24, 2002
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Minimal entropic kinetic models for simulating hydrodynamics
We derive minimal discrete models of the Boltzmann equation consistent with equilibrium thermodynamics, and which recover correct hydrodynamics in arbitrary dimensions. A simple analytical procedure…
Santosh Ansumali, Iliya V. Karlin, Hans Christian ÖttingerMay 24, 2002
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Quantum Smoluchowski equation: Escape from a metastable state
We develop a quantum Smoluchowski equation in terms of a true probability distribution function to describe quantum Brownian motion in configuration space in large friction limit at arbitrary…
Dhruba Banerjee, Bidhan Chandra Bag, Suman Kumar Banik et al.May 24, 2002
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Stirring Bose-Einstein condensate
By shining a tightly focused laser light on the condensate and moving the center of the beam along the spiral line one may stir the condensate and create vortices. It is shown that one can induce…
Bogdan Damski, Krzysztof Sacha, Jakub ZakrzewskiMay 23, 2002
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A two atomic species superfluid
We produce a quantum degenerate mixture composed by two Bose-Einstein condensates of different atomic species, 41 K and 87 Rb. We study the dynamics of the superfluid system in an elongated magnetic…
G. Modugno, M. Modugno, F. Riboli et al.May 23, 2002
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Charged Particle-Image Interaction Near a Conducting Surface
The interaction of a bulk electron with conducting surfaces is studied by means of Bohm-Pines transformation in the second quantization formalism. The effective interaction potentials are obtained…
M. Durgut, E. MeteMay 22, 2002
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Linear spin waves in a trapped Bose gas
An ultra-cold Bose gas of two-level atoms can be thought of as a spin-1/2 Bose gas. It supports spin-wave collective modes due to the exchange mean field. Such collective spin oscillations have been…
T. Nikuni, J. E. Williams, C. W. ClarkMay 21, 2002
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Multiple Functionality in Nanotube Transistors
Calculations of quantum transport in a carbon nanotube transistor show that such a device offers unique functionality. It can operate as a ballistic field-effect transistor, with excellent…
F. Leonard, J. TersoffMay 21, 2002
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Epidemic threshold in structured scale-free networks
We analyze the spreading of viruses in scale-free networks with high clustering and degree correlations, as found in the Internet graph. For the Suscetible-Infected-Susceptible model of epidemics the…
Victor M. Eguiluz, Konstantin KlemmMay 21, 2002
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Incoherent dynamics of vibrating single-molecule transistors
We study the tunneling conductance of nano-scale quantum ``shuttles'' in connection with a recent experiment (H. Park et al., Nature, 407, 57 (2000)) in which a vibrating C60 molecule was…
K. D. McCarthy, N. Prokof'ev, M. T. TuominenMay 20, 2002
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On gauge-invariant Green function in 2+1 dimensional QED
Both the gauge-invariant fermion Green function and gauge-dependent conventional Green function in 2+1 dimensional QED are studied in the large N limit. In temporal gauge, the infra-red…
Jinwu YeMay 20, 2002
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Persistent currents in a circular array of Bose-Einstein condensates
A ring-shaped array of Bose-Einstein condensed atomic gases can display circular currents if the relative phase of neighboring condensates becomes locked to certain values. It is shown that,…
Gh. -S. ParaoanuMay 20, 2002
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On the ground-state properties of antiferromagnetic half-integer spin chains with long-range interactions
The Lieb-Shultz-Mattis theorem is extended to Heisenberg chains with long-range interactions. We prove that the half-integer spin chain has no gap, if it possesses unique ground state and the…
Tigran HakobyanMay 20, 2002
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The $-game
We propose a payoff function extending Minority Games (MG) that captures the competition between agents to make money. In constrast with previous MG, the best strategies are not always targeting the…
Jorgen Vitting Andersen, Didier SornetteMay 20, 2002
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Wannier functions analysis of the nonlinear Schrödinger equation with a periodic potential
In the present Letter we use the Wannier function basis to construct lattice approximations of the nonlinear Schrödinger equation with a periodic potential. We show that the nonlinear Schrödinger…
G. L. Alfimov, P. G. Kevrekidis, V. V. Konotop et al.May 19, 2002
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