BOSE-EINSTEIN CONDENSATION IS DISORDERED EXCLUSION MODELS AND RELATION TO TRAFFIC FLOW

A disordered version of the one-dimensional asymmetric exclusion model where the particle hopping rates are quenched random variables is stu died. The steady state is solved exactly by use of a matrix product. I t is shown how the phenomenon of Bose condensation whereby a finite fr action of the empty sites are condensed in front of the slowest partic le may occur. Above a critical density of particles a phase transition occurs out of the low-density phase (Bose condensate) to a high-densi ty phase. An exponent describing the decrease of the steady-state velo city as the density of particles goes above the critical value is calc ulated analytically and shown to depend on the distribution of hopping rates. The relation to traffic flaw models is discussed.