Universality class of the pair contact process with diffusion

TL;DR

This paper investigates the critical behavior of the pair contact process with diffusion (PCPD) using Monte Carlo simulations, finding it belongs to the directed percolation universality class by analyzing combined density measures.

Contribution

It introduces a novel analysis method that suppresses corrections to scaling, enabling accurate determination of critical exponents for PCPD and establishing its universality class.

Findings

Critical exponents delta=0.16(2), beta=0.28(2), z=1.58 identified

Consistent with directed percolation universality class

Analysis method reduces correction-to-scaling effects

Abstract

The pair contact process with diffusion (PCPD) is studied with a standard Monte Carlo approach and with simulations at fixed densities. A standard analysis of the simulation results, based on the particle densities or on the pair densities, yields inconsistent estimates for the critical exponents. However, if a well-chosen linear combination of the particle and pair densities is used, leading corrections can be suppressed, and consistent estimates for the independent critical exponents delta=0.16(2), beta=0.28(2) and z=1.58 are obtained. Since these estimates are also consistent with their values in directed percolation (DP), we conclude that PCPD falls in the same universality class as DP.