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Full-Text Articles in Physical Sciences and Mathematics
Phase Transitions In A Driven Lattice Gas With Repulsive Interactions, K.-T. Leung, Beate Schmittmann, R. K. P. Zia
Phase Transitions In A Driven Lattice Gas With Repulsive Interactions, K.-T. Leung, Beate Schmittmann, R. K. P. Zia
Beate Schmittmann
We study a lattice gas with repulsive nearest-neighbor interactions driven to steady state by an external electric field E. Using Monte Carlo techniques on a two-dimensional system, we find, in the E-T plane, a line of second-order transitions joining a line of first-order ones, at a point which is probably tricritical. From a field theoretical model, we show that the operator associated with E is naively irrelevant for critical behavior. This expectation is borne out by the Monte Carlo result β=(1/8.
Effects Of Pollution On Critical Population Dynamics, R. Kree, B. Schaub, Beate Schmittmann
Effects Of Pollution On Critical Population Dynamics, R. Kree, B. Schaub, Beate Schmittmann
Beate Schmittmann
We investigate the effects of pollution on a population that is on the brink of extinction. In the vicinity of the associated critical point, the temporal scales of the population density fluctuations are found to be completely governed by the diffusive behavior of the pollution density fluctuations. Moreover, the mean value of the population density is found to vanish with a larger power-law exponent in the presence of pollution density fluctuations. Results are obtained within a renormaliza- tion-group calculation to O(ε) (ε=4-d, d being the spatial dimension).