The symbiotic contact process: phase transitions, hysteresis cycles, and bistability

TL;DR

This study uses Monte Carlo simulations to explore phase transitions, hysteresis, and bistability in the symbiotic contact process across different dimensions, revealing a shift from continuous to discontinuous transitions at a critical dimension.

Contribution

It provides the first numerical evidence of how the symbiotic contact process's phase transition nature changes with spatial dimension, highlighting the role of dimensionality.

Findings

Hysteresis cycles and bistability occur in infinite-dimensional graphs.

Transitions are continuous in two dimensions.

Transition nature shifts at the upper critical dimension.

Abstract

We performed Monte Carlo simulations of the symbiotic contact process on different spatial dimensions ($d$). On the complete and random graphs (infinite dimension), we observe hysteresis cycles and bistable regions, what is consistent with the discontinuous absorbing-state phase transition predicted by mean-field theory. By contrast, on a regular square lattice, we find no signs of bistability or hysteretic behavior. This result suggests that the transition in two dimensions is rather continuous. Based on our numerical observations, we conjecture that the nature of the transition changes at the upper critical dimension ($d_c$), from continuous ($d<d_c$) to discontinuous ($d>d_c$).