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DY: Fachverband Dynamik und Statistische Physik

DY 23: Statistical physics far from thermal equilibrium

DY 23.3: Vortrag

Donnerstag, 26. März 2009, 14:45–15:00, HÜL 386

Condensation in 1d systems with pair-factorized steady states — •Bartlomiej Waclaw¹, Julien Sopik², Hildegard Meyer-Ortmanns², and Wolfhard Janke¹ — ¹Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, 04009 Leipzig, Germany — ²School of Engineering and Science, Jacobs University, P. O. Box 750561, 28725 Bremen, Germany

Many models describing the transport of some conserved quantity have been proposed recently. The best known are the zero-range process and the asymmetric simple exclusion process. They are lattice models where particles jump between adjacent sites with given probability. Although they are far from equilibrium, they possess a steady state which takes a factorized form over the sites of an underlying lattice, which simplifies calculations. Recently, Evans et al. [1] have proposed a 1d model in which the steady state factorizes over N pairs of nodes: ∏_i g(m_i,m_i+1) where m_i is the number of particles at node i, and g(m,n) is defined by the dynamics of the model. If g(m,n) does not factorize, interactions between particles at neighboring nodes emerge. In this talk we examine how different choices of g(m,n) influence static properties of the steady state. In particular we observe a condensation of particles above some critical density. The condensate can be either localized at a single node, or extended over ∼ N^α nodes with 0<α<1/2, depending on the interaction strength. We calculate also the shape of the condensate and the distribution of particles.
[1] M. R. Evans, T. Hanney, and S. N. Majumdar, Phys. Rev. Lett. 97, 010602 (2006).