Long-range attraction between probe particles mediated by a driven fluid

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: 4 April 2005

Abstract

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 , 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.