Order and symmetry-breaking in the fluctuations of driven systems

TL;DR

This paper reports the first observation of a dynamical phase transition in the current fluctuations of a 2D driven diffusive system, revealing complex symmetry-breaking phenomena and the emergence of jammed density waves.

Contribution

It demonstrates the existence of a DPT in 2D systems using macroscopic fluctuation theory and uncovers the connection between rare fluctuations and self-organized structures.

Findings

Identification of a DPT in 2D driven diffusive systems

Rich phase diagram with symmetry-broken fluctuation phases

Emergence of jammed density waves hindering transport

Abstract

Dynamical phase transitions (DPTs) in the space of trajectories are one of the most intriguing phenomena of nonequilibrium physics, but their nature in realistic high-dimensional systems remains puzzling. Here we observe for the first time a DPT in the current vector statistics of an archetypal two-dimensional (2d) driven diffusive system, and characterize its properties using macroscopic fluctuation theory. The complex interplay among the external field, anisotropy and vector currents in 2d leads to a rich phase diagram, with different symmetry-broken fluctuation phases separated by lines of first- and second-order DPTs. Remarkably, different types of 1d order in the form of jammed density waves emerge to hinder transport for low-current fluctuations, revealing a connection between rare events and self-organized structures which enhance their probability.