Noise-Induced Phase Separation and Time Reversal Symmetry Breaking in Active Field Theories driven by persistent noise

TL;DR

This paper demonstrates that non-equilibrium fluctuations driven by persistent noise can induce phase separation in scalar field theories, breaking time-reversal symmetry, similar to motility-induced phase separation, with boundary-localized entropy production.

Contribution

It reveals a novel noise-driven phase separation mechanism in active field theories and links it to time-reversal symmetry breaking and entropy production.

Findings

Noise-induced phase separation occurs in non-equilibrium scalar fields.

Time-reversal symmetry breaking is localized at phase boundaries.

Persistent noise acts as an effective attractive force similar to motility-induced phase separation.

Abstract

Within the Landau-Ginzburg picture of phase transitions, scalar field theories develop phase separation because of a spontaneous symmetry-breaking mechanism. This picture works in thermodynamics but also in the dynamics of phase separation. Here we show that scalar non-equilibrium field theories undergo phase separation just because of non-equilibrium fluctuations driven by a persistent noise. The mechanism is similar to what happens in Motility-Induced Phase Separation where persistent motion introduces an effective attractive force. We observe that Noise-Induced Phase Separation occurs in a region of the phase diagram where disordered field configurations would otherwise be stable at equilibrium. Measuring the local entropy production rate to quantify the time-reversal symmetry breaking, we find that such breaking is concentrated on the boundary between the two phases.