Critical properties of the reaction-diffusion model 2A→3A, 2A→0 -: art. no. 036101

The steady-state phase diagram of the one-dimensional reaction-diffusion model 2A --> 3A, 2A-->0 is studied through the non-Hermitian density matrix renormalization group: In the absence of single-particle diffusion the model reduces to the pair-contact process, which has a phase transition in the universality class of directed percolation (DP) and an infinite number of absorbing steady states. When single-particle diffusion is added, the number of absorbing steady states is reduced to 2 and the model no longer shows DP critical behavior. The exponents theta=nu (parallel to)/nu (perpendicular to) and beta/nu (perpendicular to) are calculated numerically. The value of beta/nu (perpendicular to), is close to the value of the parity conserving universality class, in spite of the absence of local conservation laws.