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Condensed Matter papers — page 93

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Shaking a Box of Sand
We present a simple model of a vibrated box of sand, and discuss its dynamics in terms of two parameters reflecting static and dynamic disorder respectively. The fluidised, intermediate and frozen…
Peter F. Stadler, Anita Mehta, Jean-Marc LuckMar 3, 2001
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Aging and memory phenomena in magnetic and transport properties of vortex matter: a brief review
There is mounting experimental evidence that strong off-equilibrium phenomena, such as ``memory'' or ``aging'' effects, play a crucial role in the physics of vortices in type II…
Mario Nicodemi, Henrik Jeldtoft JensenMar 2, 2001
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Calculation of NMR Properties of Solitons in Superfluid 3He-A
Superfluid 3He-A has domain-wall-like structures, which are called solitons. We calculate numerically the structure of a splay soliton. We study the effect of solitons on the…
R. Hänninen, E. V. ThunebergMar 2, 2001
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Femtosecond to picosecond electron-energy relaxation and Froehlich coupling in quantum dots
Electron relaxation in quantum dots is studied theoretically in polar semiconductor materials, with an emphasis put on the phonon-bottleneck problem and electron-LO-phonon coupling. The theory is…
K. Kral, Z. KhasMar 2, 2001
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Fermi surface renormalization in Hubbard ladders
We derive the one-loop renormalization equations for the shift in the Fermi-wavevectors for one-dimensional interacting models with four Fermi-points (two left and two right movers) and two Fermi…
Kim Louis, J. V. Alvarez, Claudius GrosMar 1, 2001
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Effective gauge field theory of the t-J model in the charge-spin separated state and its transport properties
We study the slave-boson t-J model of cuprates with high superconducting transition temperatures, and derive its low-energy effective field theory for the charge-spin separated state in a…
I. Ichinose, T. Matsui, M. OnodaMar 1, 2001
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Generalized yrast states of a Bose condensate in harmonic trap for a universality class of repulsive interactions
For a system of N bosons in a 2d harmonic trap with frequency omega, interacting via repulsive forces V<<omega, we develop supersymmetric method to find the lowest energy states of rotating Bose…
M. S. Hussein, O. K. VorovFeb 28, 2001
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A Statistical Analysis of Log-Periodic Precursors to Financial Crashes
Motivated by the hypothesis that financial crashes are macroscopic examples of critical phenomena associated with a discrete scaling symmetry, we reconsider the evidence of log-periodic precursors to…
James FeigenbaumFeb 28, 2001
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Response theory for time-resolved second-harmonic generation and two-photon photoemission
A unified response theory for the time-resolved nonlinear light generation and two-photon photoemission (2PPE) from metal surfaces is presented. The theory allows to describe the dependence of the…
C. Timm, K. H. BennemannFeb 27, 2001
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Conformal symmetry and the nonlinear Schrodinger equation
We show that the width of the wave-packet of a class of generalized nonlinear Schrodinger equations (NLSE) trapped in an arbitrary time-dependent harmonic well in any dimensions is universally…
Pijush K. GhoshFeb 27, 2001
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Electronic properties of single and coupled anisotropic quantum dots in a magnetic field, spin interactions and switching
We determined the eigenstates of a single electron in a parabolic anisotropic 2D quantum dot in a magnetic field. Using obtained expressions for these eigenstates, we study the spin coupling J…
Alexander P. ItinFeb 26, 2001
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Quantum Group based Modeling for the description of high temperature superconductivity and antiferromagnetism: Some supporting evidence
Following our recent conjecture to model the phenomenona of antiferromagnetism and superconductivity by quantum symmetry groups, we propose in the present note three toy models, namely, one based on…
Sher AlamFeb 25, 2001
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The Bose Metal: gauge field fluctuations and scaling for field tuned quantum phase transitions
In this paper, we extend our previous discussion of the Bose metal to the field tuned case. We point out that the recent observation of the metallic state as an intermediate phase between the…
D. Das, S. DoniachFeb 23, 2001
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Structural Properties of Self-Attracting Walks
Self-attracting walks (SATW) with attractive interaction u > 0 display a swelling-collapse transition at a critical uc for dimensions d >= 2, analogous to the Θtransition of polymers. We…
A. Ordemann, E. Tomer, G. Berkolaiko et al.Feb 22, 2001
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Interface Depinning in the Absence of External Driving Force
We study the pinning-depinning phase transition of interfaces in the quenched Kardar-Parisi-Zhang model as the external driving force F goes towards zero. For a fixed value of the driving force we…
JJ Ramasco, JM Lopez, MA RodriguezFeb 22, 2001
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Local gauge invariance and formation of topological defects
In superconductors, and in other systems with a local U(1) gauge invariance, there are two mechanisms that form topological defects in phase transitions. In addition to the standard Kibble mechanism,…
A. RajantieFeb 22, 2001
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Large-Scale Synchrony in Weakly Interacting Automata
We study the behavior of two spatially distributed (sandpile) models which are weakly linked with one another. Using a Monte-Carlo implementation of the renormalization group and algebraic methods,…
Eric J. Friedman, A. S. LandsbergFeb 21, 2001
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Assessing the Predictability of Social and Economic Time-Series Data: the example of crime in the UK
Policy targets are being set increasingly for social and economic variables in the UK. This approach requires that reasonably successful ex ante forecasts can be made. We propose a general…
Paul Ormerod, Laurence SmithFeb 21, 2001
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Power Law Distribution of the Duration and Magnitude of Recessions in Capitalist Economies : Breakdown of Scaling
Power law distributions of macroscopic observables are ubiquitous in both the natural and social sciences. They are indicative of correlated, cooperative phenomena between groups of interacting…
P Ormerod, C MounfieldFeb 21, 2001
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Disorder Induced Ferromagnetism in CaRuO3
The magnetic ground state of perovskite structure CaRuO3 has been enigmatic for decades. Here we show that paramagnetic CaRuO3 can be made ferromagnetic by very small amounts of partial substitution…
T. He, R. J. CavaFeb 21, 2001
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Current Reversals in Chaotic Ratchets
The problem of the classical deterministic dynamics of a particle in a periodic asymmetric potential of the ratchet type is addressed. When the inertial term is taken into account, the dynamics can…
José L. MateosFeb 21, 2001
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Bose-Einstein condensation in variable dimensionality
We introduce dimensional perturbation techniques to Bose-Einstein condensation of inhomogeneous alkali gases (BEC). The perturbation parameter is delta=1/kappa, where kappa depends on the effective…
B. A. McKinney, D. K. WatsonFeb 20, 2001
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Quantum effects in the collective light scattering by coherent atomic recoil in a Bose-Einstein condensate
We extend the semiclassical model of the collective atomic recoil laser (CARL) to include the quantum mechanical description of the center-of-mass motion of the atoms in a Bose-Einstein condensate…
N. Piovella, M. Gatelli, R. BonifacioFeb 20, 2001
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Random Matrix Theory and the Failure of Macroeconomic Forecasts
By scientific standards, the accuracy of short-term economic forecasts has been poor, and shows no sign of improving over time. We form a delay matrix of time-series data on the overall rate of…
P Ormerod, C MounfieldFeb 20, 2001
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On the Belitz-Kirkpatrick comment on "Specific heat of a Fermi system near ferromagnetic quantum phase transition", by I.Grosu, D.Bodea and M.Crisan (cond-mat/0101392)
We reply to Belitz and Kirkpatrick comment cond-mat/0102064, on cond-mat/0101392.
M. Crisan, I. Grosu, D. BodeaFeb 20, 2001
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