title: Bose-Einstein condensation and a two-dimensional walk model.
abstract: We introduce a two-dimensional walk model in which a random walker can only move on the first quarter of a two-dimensional plane. We calculate the partition function of this walk model using a transfer matrix method and show that the model undergoes a phase transition. Surprisingly the partition function of this two-dimensional walk model is exactly equal to that of a driven-diffusive system defined on a discrete lattice with periodic boundary conditions in which a phase transition occurs from a high-density to a low-density phase. The driven-diffusive system can be mapped to a zero-range process where the particles can accumulate in a single lattice site in the low-density phase. This is very reminiscent of real-space Bose-Einstein condensation.
authors: Physics Department, Bu-Ali Sina University, 65174-4161 Hamedan, Iran. farhad@ipm.ir
authors: Farhad H
authors: FH
authors: Jafarpour