Suppression of discontinuous phase transitions by particle diffusion

TL;DR

This study shows that particle diffusion in a 2D Brownian Potts model transforms what would be a discontinuous phase transition into a continuous one, highlighting the impact of dynamical disorder.

Contribution

The paper demonstrates that diffusion-induced dynamical disorder suppresses discontinuous phase transitions in the 2D q-state Potts model, leading to continuous transitions for q>4.

Findings

Continuous phase transition observed for q>4 due to diffusion

Diffusion suppresses phase coexistence and discontinuity

Numerical evidence supports the transition change

Abstract

We investigate the phase transitions of the $q$-state Brownian Potts model in two dimensions (2d) comprising Potts spins that diffuse like Brownian particles and interact ferromagnetically with other spins within a fixed distance. With extensive Monte Carlo simulations we find a continuous phase transition from a paramagnetic to a ferromagnetic phase even for $q>4$. This is in sharp contrast to the existence of a discontinuous phase transition in the equilibrium $q$-state Potts model in 2d with $q>4$. We present detailed numerical evidence for a continuous phase transition and argue that diffusion generated dynamical positional disorder suppresses phase coexistence leading to a continuous transition.