Metastability in Schloegl’s second model for autocatalysis: Lattice-gas realization with particle diffusion

We analyze metastability associated with a discontinuous nonequilibrium phase transition in a stochastic lattice-gas realization of Schloegl's second model for autocatalysis. This model realization involves spontaneous annihilation, autocatalytic creation, and diffusion of particles on a square lattice, where creation at empty sites requires an adjacent diagonal pair of particles. This model, also known as the quadratic contact process, exhibits discontinuous transition between a populated active state and a particle-free vacuum or "poisoned" state, as well as generic two-phase coexistence. The poisoned state exists for all particle annihilation rates p>0 and hop rates h≥0 and is an absorbing state in the sense of Markovian processes. The active or reactive steady state exists only for p below a critical value, pe = pe (h), but a metastable extension appears for a range of higher p up to an effective upper spinodal point, ps+ = ps+ (h) (i.e. ps+ > pe). For selected h, we assess the location of ps+ (h) by characterizing both the poisoning kinetics and the propagation of interfaces separating vacuum and active states as a function of p. © 2010 The American Physical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe