93 research outputs found
Anisotropic finite-size scaling analysis of a three-dimensional driven-diffusive system
We study the standard three-dimensional driven diffusive system on a simple
cubic lattice where particle jumps along a given lattice direction are biased
by an infinitely strong field, while those along other directions follow the
usual Kawasaki dynamics. Our goal is to determine which of the several existing
theories for critical behavior is valid. We analyze finite-size scaling
properties using a range of system shapes and sizes far exceeding previous
studies. Four different analytic predictions are tested against the numerical
data. Binder and Wang's prediction does not fit the data well. Among the two
slightly different versions of Leung, the one including the effects of a
dangerous irrelevant variable appears to be better. Recently proposed isotropic
finite-size scaling is inconsistent with our data from cubic systems, where
systematic deviations are found, especially in scaling at the critical
temperature.Comment: 12 pages, 14 PS figures, RevTeX; extensively revise
PHASE TRANSITIONS IN TWO-SPECIES ASYMMETRIC DIFFUSIVE LATTICE GASES(Session IV : Structures & Patterns, The 1st Tohwa University International Meeting on Statistical Physics Theories, Experiments and Computer Simulations)
この論文は国立情報学研究所の電子図書館事業により電子化されました
Identification and Estimation of Structural-Change Models with Misclassification
Consider a simple change-point model with a binary regressor. We examine the consistency of the change-point estimator when the regressor is subject to misclassification. It is found that the time of change can always be identified. Further, special cases where the structural parameters can also be identified are discussed. Simulation evidence is provided.
Response in kinetic Ising model to oscillating magnetic fields
Ising models obeying Glauber dynamics in a temporally oscillating magnetic
field are analyzed. In the context of stochastic resonance, the response in the
magnetization is calculated by means of both a mean-field theory with
linear-response approximation, and the time-dependent Ginzburg-Landau equation.
Analytic results for the temperature and frequency dependent response,
including the resonance temperature, compare favorably with simulation data.Comment: RevTex, 6 pages, two-column, 2 figure
Novel Phases and Finite-Size Scaling in Two-Species Asymmetric Diffusive Processes
We study a stochastic lattice gas of particles undergoing asymmetric
diffusion in two dimensions. Transitions between a low-density uniform phase
and high-density non-uniform phases characterized by localized or extended
structure are found. We develop a mean-field theory which relates
coarse-grained parameters to microscopic ones. Detailed predictions for
finite-size () scaling and density profiles agree excellently with
simulations. Unusual large- behavior of the transition point parallel to
that of self-organized sandpile models is found.Comment: 7 pages, plus 6 figures uuencoded, compressed and appended after
source code, LATeX, to be published as a Phys. Rev. Let
Phase transition in a spring-block model of surface fracture
A simple and robust spring-block model obeying threshold dynamics is
introduced to study surface fracture of an overlayer subject to stress induced
by adhesion to a substrate. We find a novel phase transition in the crack
morphology and fragment-size statistics when the strain and the substrate
coupling are varied. Across the transition, the cracks display in succession
short-range, power-law and long-range correlations. The study of stress release
prior to cracking yields useful information on the cracking process.Comment: RevTeX, 4 pages, 4 Postscript figures included using epsfi
Pattern formation and selection in quasi-static fracture
Fracture in quasi-statically driven systems is studied by means of a discrete
spring-block model. Developed from close comparison with desiccation
experiments, it describes crack formation induced by friction on a substrate.
The model produces cellular, hierarchical patterns of cracks, characterized by
a mean fragment size linear in the layer thickness, in agreement with
experiments. The selection of a stationary fragment size is explained by
exploiting the correlations prior to cracking. A scaling behavior associated
with the thickness and substrate coupling, derived and confirmed by
simulations, suggests why patterns have similar morphology despite their
disparity in scales.Comment: 4 pages, RevTeX, two-column, 5 PS figures include
Heuristic derivation of continuum kinetic equations from microscopic dynamics
We present an approximate and heuristic scheme for the derivation of
continuum kinetic equations from microscopic dynamics for stochastic,
interacting systems. The method consists of a mean-field type, decoupled
approximation of the master equation followed by the `naive' continuum limit.
The Ising model and driven diffusive systems are used as illustrations. The
equations derived are in agreement with other approaches, and consequences of
the microscopic dependences of coarse-grained parameters compare favorably with
exact or high-temperature expansions. The method is valuable when more
systematic and rigorous approaches fail, and when microscopic inputs in the
continuum theory are desirable.Comment: 7 pages, RevTeX, two-column, 4 PS figures include
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