Universality in the pair contact process with diffusion

TL;DR

This study investigates the universality class of the pair contact process with diffusion, showing that its critical behavior aligns with directed percolation but exhibits an intermediate regime resembling parity conservation.

Contribution

It provides a comprehensive analysis combining Monte Carlo and DMRG methods to explore critical exponents and universality in the pair contact process with diffusion.

Findings

Critical exponents approach directed percolation values asymptotically.

An intermediate regime shows dynamics similar to a parity conserving process.

Effective exponents behave nonmonotonically over time and system size.

Abstract

The pair contact process with diffusion is studied by means of multispin Monte Carlo simulations and density matrix renormalization group calculations. Effective critical exponents are found to behave nonmonotonically as functions of time or of system length and extrapolate asymptotically towards values consistent with the directed percolation universality class. We argue that an intermediate regime exists where the effective critical dynamics resembles that of a parity conserving process.