Driven binary mixtures: Clustering and giant diffusion

¹ Dipartimento di Fisica, Università di Camerino, I-62032 Camerino, Italy
² Frontier Research System, The Institute of Physical and Chemical Research (RIKEN) Wako-shi, Saitama, 351-0198, Japan
³ Department of Physics, Loughborough University - Loughborough LE11 3TU, UK
⁴ Center for Theoretical Physics, Department of Physics, University of Michigan Ann Arbor, MI 48109-1040, USA

Received: 24 November 2005
Accepted: 20 December 2005

Abstract

We study noise-assisted transport in a binary mixture of overdamped interacting particles. As one species (termed “active”) is subject to a weak dc drive, the other one (termed “passive”) can be dragged along due to the clustering of particles of both species. On increasing the external drive, clusters of different size fragment at different thresholds that depend on the mixture temperature, the inter-particle interaction strength, and the densities of both species of particles. Moreover, normal self-diffusion of both species at the fragmentation thresholds undergoes a giant enhancement simultaneous with a markedly negative cross-diffusion coefficient.