Center for Stochastic Processes in Science and Engineering (CSPISE)

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Browsing Center for Stochastic Processes in Science and Engineering (CSPISE) by Subject "biased diffusion"

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    Field-induced vacancy localization in a driven lattice gas: Scaling of steady states
    Thies, M.; Schmittmann, Beate (American Physical Society, 2000-01)
    With the help of Monte Carlo simulations and a mean-field theory, we investigate the ordered steady-state structures resulting from the motion of a single vacancy on a periodic lattice which is filled with two species of oppositely "charged" particles. An external field biases particle-vacancy exchanges according to the particle's charge, subject to an excluded volume constraint. The steady state exhibits charge segregation, and the vacancy is localized at one of the two characteristic interfaces. Charge and hole density profiles, an appropriate order parameter, and the interfacial regions themselves exhibit characteristic scaling properties with system size and field strength. The lattice spacing is found to play a significant role within the mean-field theory.
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    Steady states of a nonequilibrium lattice gas
    Lyman, E.; Schmittmann, Beate (American Physical Society, 2005-09)
    We present a Monte Carlo study of a lattice gas driven out of equilibrium by a local hopping bias. Sites can be empty or occupied by one of two types of particles, which are distinguished by their response to the hopping bias. All particles interact via excluded volume and a nearest-neighbor attractive force. The main result is a phase diagram with three phases: a homogeneous phase and two distinct ordered phases. Continuous boundaries separate the homogeneous phase from the ordered phases, and a first-order line separates the two ordered phases. The three lines merge in a nonequilibrium bicritical point.