On the absorbing-state phase transition in the one-dimensional triplet creation model

We study the lattice reaction-diffusion model 3A -> 4A, A -> 0 ('triplet creation') using numerical simulations and n-site approximations. The simulation results suggest that the phase transition is discontinuous at high diffusion rates. In this regime the order parameter appears to be a discontinuous function of the creation rate; no evidence of a stable interface between active and absorbing phases is found. Based on an effective mapping to a modified compact directed percolation process, we shall nevertheless argue that the transition is continuous, despite the seemingly discontinuous phase transition suggested by studies of finite systems.