Long-range attraction between probe particles mediated by a driven fluidE. Levine1, D. Mukamel1 and G. M. Schütz2
1 Department of Physics of Complex Systems, Weizmann Institute of Science Rehovot, Israel 76100
2 Institut für Festkörperforschung, Forschungszentrum Jülich - 52425 Jülich, Germany
received 21 February 2005; accepted in final form 4 April 2005
published online 29 April 2005
The effective interaction between two probe particles in a one-dimensional driven system is studied. The analysis is carried out using an asymmetric simple exclusion process with nearest-neighbor interactions. It is found that the driven fluid mediates an effective long-range attraction between the two probes, with a force that decays at large distances x as -b/x, where b is a function of the interaction parameters. Depending on the amplitude b, the two probes may form one of three states: a) an unbound state, where the distance grows diffusively with time; b) a weakly bound state, in which the distance grows sub-diffusively; and c) a strongly bound state, where the average distance stays finite in the long-time limit. Similar results are found for the behavior of any finite number of probes.
02.50.Ey - Stochastic processes.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
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