Quadrupolar gyration of a Brownian particle in a confining ring

TL;DR

This paper introduces a minimal theoretical model demonstrating that a Brownian particle in a ring-shaped trap, driven by anisotropic thermal fluctuations, exhibits a quadrupolar vortex pattern in its steady-state flux, revealing emergent symmetry breaking and nonequilibrium phenomena.

Contribution

The study uncovers a novel quadrupolar gyration pattern in a passive Brownian particle driven by anisotropic heat baths, highlighting emergent symmetry breaking in minimal nonequilibrium systems.

Findings

Discovery of quadrupolar vortex pattern in particle flux

Demonstration of symmetry breaking due to temperature anisotropy

Identification of irreversible entropy production in the system

Abstract

We develop a minimal theoretical model that reveals a structured steady-state flux field with four alternating local circulation, a phenomenon we refer to as quadrupolar gyration. A passive Brownian particle is confined to move in a ring-shaped trap and driven far from equilibrium solely by anisotropic thermal fluctuations from two orthogonal heat baths held at different temperatures. By breaking detailed balance, this fundamental temperature anisotropy induces a robust nonequilibrium steady state characterized by probability currents of the particle's motion. Remarkably, these currents self-organize into a distinctive quadrupolar vortex pattern, providing a clear signature of emergent symmetry breaking, irreversible entropy production, and coherent motion in minimal passive systems.