Real-space renormalization for reaction-diffusion systems

The stationary state of stochastic processes such as reaction-diffusion sys tems can be related to the ground state of a suitably defined quantum Hamil tonian. Using this analogy, we investigate the applicability of a real-spac e renormalization group approach, originally developed for quantum spin sys tems, to interacting particle systems. We apply the technique to an exactly solvable reaction-diffusion system and to the contact process (both in d = 1). In the former case, several exact results are recovered. For the conta ct process, surprisingly good estimates of critical parameters are obtained from a small-cell renormalization.