Stochastic thermodynamics of a confined colloidal suspension under shear flow

TL;DR

This study uses Brownian dynamics simulations to explore the thermodynamic behavior of confined colloidal suspensions under shear flow, revealing multiple steady states, collective particle motions, and the many-body nature of work and heat distributions.

Contribution

It introduces a detailed analysis of non-equilibrium steady states in confined colloids under shear, highlighting many-body effects and collective dynamics not previously characterized.

Findings

Identification of three distinct steady states with unique rheological responses

Observation of collective zig-zag particle motion at high shear rates

Bistability in phase synchronization affecting work distributions

Abstract

Based on Brownian dynamics simulations, we investigate the thermodynamic signatures of non-equilibrium steady states in a confined colloidal suspensions under shear flow. Specifically, we consider a thin film consisting of charged particles in narrow slit-pore confinement, forming two layers with quadratic in-plane structure in equilibrium. This many-body system displays three distinct steady states, characterized by unique dynamical and rheological response to the applied shear flow. Calculating the work and heat, we find that both quantities indicate the different states by their mean and by their distributions. A particularly interesting situation occurs at large shear rates, where the particles perform a collective zig-zag motion. Here, we find a bistability regarding the degree of phase synchronization of the particle motion. It turns out that this bistability is key to understanding the resulting ensemble-averaged work distributions. For all states, we compare the work and heat distributions to those of effective single-particle systems. By this, we aim at identifying the many-body character of the stochastic thermodynamic quantities.