RENORMALIZATION OF NONEQUILIBRIUM SYSTEMS WITH CRITICAL STATIONARY STATES

We introduce the general formulation of a renormalization method suita ble to study the critical properties of nonequilibrium systems with st eady states: the dynamically driven renormalization group. We renormal ize the time evolution operator by computing the rescaled time transit ion rate between coarse grained states. The obtained renormalization e quations are coupled to a stationarity condition which provides the ap proximate nonequilibrium statistical weights of steady-state configura tions to be used in the calculations. in this way we are able to write recursion relations for the parameter evolution under scale change, f rom which we can extract numerical values for the critical exponents. This general framework allows the systematic analysis of several model s showing self-organized criticality in terms of usual concepts of pha se transitions and critical phenomena.