Pair contact process with diffusion of pairs

TL;DR

This paper investigates a variant of the pair contact process with pair diffusion but no individual particle diffusion, demonstrating DP-like critical behavior through quasistationary simulations across different diffusion probabilities.

Contribution

It introduces and analyzes a PCP variant with pair-only diffusion, revealing its critical behavior aligns with the directed percolation universality class.

Findings

Critical behavior consistent with DP universality class.

Diffusion probability variations do not alter the DP-like critical behavior.

Quasistationary simulations effectively characterize the phase transition.

Abstract

The pair contact process (PCP) is a nonequilibrium stochastic model which, like the basic contact process (CP), exhibits a phase transition to an absorbing state. The two models belong to the directed percolation (DP) universality class, despite the fact that the PCP possesses infinitely many absorbing configurations whereas the CP has but one. The critical behavior of the PCP with hopping by particles (PCPD) is as yet unclear. Here we study a version of the PCP in which nearest-neighbor particle {\it pairs} can hop but individual particles cannot. Using quasistationary simulations for three values of the diffusion probability ($D=0.1$, 0.5 and 0.9), we find convincing evidence of DP-like critical behavior.