1ST-ORDER PHASE-TRANSITION IN A ONE-DIMENSIONAL NONEQUILIBRIUM MODEL

We present an example of a single-component, one-dimensional interacting particle system with a discontinuous transition into an absorbing state. The basic processes in the model are spontaneous annihilation (X --> 0), autocatalytic creation by trimers (3X --> 4X), and hopping. The transition is continuous, and in the directed percolation class, for low diffusion rates, and first order for sufficiently high diffusion rates. The transition in a similar model with creation by pairs (2X --> 3X) remains continuous even at high diffusion rates.