TY - Dissertation
T1 - Monte Carlo and Series Expansion Studies of the Anisotropic Driven Ising Lattice Gas Phase Diagram
A1 - Shaw, Leah Belinda
UR - https://bonnus.ulb.uni-bonn.de/SummonRecord/FETCH-ndltd_primary_oai_union_ndltd_org_VTETD_oai_vtechworks_lib_vt_edu_10919_318510
N2 - While the statistical mechanics of systems in thermal equilibrium is a well established discipline, nonequilibrium systems are fundamentally much less well understood, even though most natural phenomena fall into the
latter category. In particular, there is as yet no nonequilibrium analog
for the systematic formalism of Gibbs ensembles. Rather than deal with the
difficult problem of general nonequilibrium systems, this study is
restricted to the steady states of a simple model whose equilibrium
properties are well known.
The Ising lattice gas displays a number of surprising phenomena when
driven into nonequilibrium steady states. This study extends previous work
to a more general model with anisotropic interparticle interactions. Using
Monte Carlo simulations, we obtain the phase diagram for the model,
controlled by the driving field, temperature, and anisotropy parameter a . Under saturation drive, the
shift in the transition temperature between ordered and disordered states
can be either positive or negative, depending on a . The possible
existence at large a of an additional phase ordered in only one
direction is discussed. For finite drives, both first and second order
transitions are observed. A novel technique for locating the first order
transition line is presented.
Some aspects of the phase diagram can be predicted by investigating the
two-point correlation function to first order in a high temperature series
expansion. However, the series expansion fails to predict even
qualitatively the a -dependence of the critical temperature.
Master of Science
KW - driven lattice gas
KW - high temperature expansion
KW - Monte Carlo simulation
ER -