BOUNDARY-INDUCED PHASE-TRANSITIONS IN EQUILIBRIUM AND NONEQUILIBRIUM SYSTEMS

Boundary conditions may change the phase diagram of non-equilibrium st atistical systems like the one-dimensional asymmetric simple exclusion process with and without particle number conservation. Using the quan tum Hamiltonian approach, the model is mapped onto an XXZ quantum chai n and solved using the Bethe ansatz. This system is related to a two-d imensional vertex model in thermal equilibrium. The phase transition c aused by a point-like boundary defect in the dynamics of the one-dimen sional exclusion model is in the same universality class as a continuo us (bulk) phase transition of the two-dimensional vertex model caused by a line defect at its boundary.