Dresden 2011 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 10: Posters I

DY 10.1: Poster

Montag, 14. März 2011, 17:00–19:00, P4

Zeroth law and fluctuation relations for driven lattice gases in contact: A numerical study — •Robert Ramsperger, Punyabrata Pradhan, and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany

We numerically study two-dimensional driven lattice gases to check the existence of an intensive thermodynamic variable which could determine “equilibration” between two driven lattice-gas systems being brought into contact [a part of the detailed results discussed here have appeared in Phys. Rev. Lett. 105, 150601 (2010)]. We consider driven interacting particle systems where the microscopic interaction strengths and driving fields may be different in each of the systems. Two such systems in contact can exchange particles through the contact area with the total number of particles conserved. The contact area consists of a small number of sites (“weak contact”) or a large number of sites (“strong contact”). Interestingly, we find that, to a very good approximation, there is an intensive variable, like equilibrium chemical potential, which determines the final steady state of two driven lattice gases in contact. Moreover, in the weak contact limit, a fluctuation-response relation between the fluctuations in particle-number and the corresponding susceptibility is also well satisfied. We also discuss the observable violations to these simple thermodynamic laws. We study in detail how the densities and the fluctuations in a driven system in contact with a particle reservoir depend on the driving field, size and shape of the system, size and shape of the contact area as well as the properties of the reservoir.