13,311 research outputs found
Exact Expressions for Minor Hysteresis Loops in the Random Field Ising Model on a Bethe Lattice at Zero Temperature
We obtain exact expressions for the minor hysteresis loops in the
ferromagnetic random field Ising model on a Bethe lattice at zero temperature
in the case when the driving field is cycled infinitely slowly.Comment: Replaced with the published versio
Self-Diffusion in 2D Dusty Plasma Liquids: Numerical Simulation Results
We perform Brownian dynamics simulations for studying the self-diffusion in
two-dimensional (2D) dusty plasma liquids, in terms of both mean-square
displacement and velocity autocorrelation function (VAF). Super-diffusion of
charged dust particles has been observed to be most significant at infinitely
small damping rate for intermediate coupling strength, where the
long-time asymptotic behavior of VAF is found to be the product of and
. The former represents the prediction of early theories in
2D simple liquids and the latter the VAF of a free Brownian particle. This
leads to a smooth transition from super-diffusion to normal diffusion, and then
to sub-diffusion with an increase of the damping rate. These results well
explain the seemingly contradictory scattered in recent classical molecular
dynamics simulations and experiments of dusty plasmas.Comment: 10 pages 5 figures, accepted by PR
Hysteresis in the Random Field Ising Model and Bootstrap Percolation
We study hysteresis in the random-field Ising model with an asymmetric
distribution of quenched fields, in the limit of low disorder in two and three
dimensions. We relate the spin flip process to bootstrap percolation, and show
that the characteristic length for self-averaging increases as in 2d, and as in 3d, for disorder
strength much less than the exchange coupling J. For system size , the coercive field varies as for
the square lattice, and as on the cubic lattice.
Its limiting value is 0 for L tending to infinity, both for square and cubic
lattices. For lattices with coordination number 3, the limiting magnetization
shows no jump, and tends to J.Comment: 4 pages, 4 figure
Exact Solution of Return Hysteresis Loops in One Dimensional Random Field Ising Model at Zero Temperature
Minor hysteresis loops within the main loop are obtained analytically and
exactly in the one-dimensional ferromagnetic random field Ising-model at zero
temperature. Numerical simulations of the model show excellent agreement with
the analytical results
Analysis of wasp-waisted hysteresis loops in magnetic rocks
The random-field Ising model of hysteresis is generalized to dilute magnets
and solved on a Bethe lattice. Exact expressions for the major and minor
hysteresis loops are obtained. In the strongly dilute limit the model provides
a simple and useful understanding of the shapes of hysteresis loops in magnetic
rock samples.Comment: 11 pages, 4 figure
Quantum Trivelpiece-Gould waves in a magnetized dense plasma
The dispersion relation for the electrostatic waves below the electron plasma
frequency in a dense quantum plasma is derived by using the magnetohydrodynamic
model. It is shown that in the classical case the dispersion relation reduces
to the expression obtained for the well-known Trivelpiece-Gould (TG) modes.
Attention is also devoted to the case of solitary waves associated with the
nonlinear TG modes.Comment: 8 pages, 0 figure
Tour-based Travel Mode Choice Estimation based on Data Mining and Fuzzy Techniques
This paper extends tour-based mode choice model, which mainly includes individual trip level interactions, to include
linked travel modes of consecutive trips of an individual. Travel modes of consecutive trip made by an individual in a
household have strong dependency or co-relation because individuals try to maintain their travel modes or use a few
combinations of modes for current and subsequent trips. Traditionally, tour based mode choice models involved nested
logit models derived from expert knowledge. There are limitations associated with this approach. Logit models assumes
i) specific model structure (linear utility model) in advance; and, ii) it holds across an entire historical observations.
These assumptions about the predefined model may be representative of reality, however these rules or heuristics
for tour based mode choice should ideally be derived from the survey data rather than based on expert knowledge/
judgment. Therefore, in this paper, we propose a novel data-driven methodology to address the issues identified in tour
based mode choice. The proposed methodology is tested using the Household Travel Survey (HTS) data of Sydney
metropolitan area and its performances are compared with the state-of-the-art approaches in this area
Oblique amplitude modulation of dust-acoustic plasma waves
Theoretical and numerical studies are presented of the nonlinear amplitude
modulation of dust-acoustic (DA) waves propagating in an unmagnetized three
component, weakly-coupled, fully ionized plasma consisting of electrons,
positive ions and charged dust particles, considering perturbations oblique to
the carrier wave propagation direction. The stability analysis, based on a
nonlinear Schroedinger-type equation (NLSE), shows that the wave may become
unstable; the stability criteria depend on the angle between the
modulation and propagation directions. Explicit expressions for the instability
rate and threshold have been obtained in terms of the dispersion laws of the
system. The possibility and conditions for the existence of different types of
localized excitations have also been discussed.Comment: 21 pages, 6 figures, to appear in Physica Script
- …