Transport with hard-core interaction in a chain of asymmetric cavities

SUÁREZ, GONZALO PABLO; HOYUELOS, MIGUEL; MÁRTIN, HÉCTOR

Boston, MA

Conferencia; XXVI IUPAP Conference on Computational Physics, CCP2014; 2014

Boston University

We studied the transport process of overdamped Brownian particles, in a chain of asymmetric cavities, interacting through a hard-core potential. When a force is applied in opposite directions a difference in the drift velocity of the particles inside the cavity can be observed. Previous works on similar systems deal with the low-concentration regime, in which the interaction is irrelevant. In this case it was found that large particles show a stronger asymmetry in the drift velocity when a small force is applied, allowing the separation of different size particles [1]. We found that when the interaction between particles is considered, the behavior of the system is substantially different. Simulating this system with the Monte Carlo method, we proved that, when the concentration increases the small particles are the ones that show a stronger asymmetry. For the case where the jump length is equal to the size of the particles, we took advantage of the particle-vacancy analogy to predict that the left and right currents are almost equal in a region around concentration 0.5 despite the asymmetry of the cavity. We also introduced a modified Fokker-Planck equation to describe this system analytically. References : [1] D. Reguera, A. Luque, P. S. Burada, G. Schmid, J. M. Rubí, and P. Hänggi, Phys. Rev. Lett. 108, 020604 (2012)