Temporal reversibility of a fluid mixture under concentration gradient

TL;DR

This study uses molecular dynamics simulations to confirm that a binary fluid mixture under concentration gradients exhibits time-reversible behavior even when driven out of equilibrium, supporting previous stochastic predictions.

Contribution

The paper provides the first experimental-like evidence via simulations that non-equilibrium fluid mixtures can be temporally reversible, validating stochastic theory predictions.

Findings

Simulation confirms time-reversibility of the system out of equilibrium

Supports stochastic analysis predictions with microscopic evidence

Demonstrates non-equilibrium steady states can be reversible

Abstract

A binary fluid mixture in contact with lateral particle reservoirs is considered. By imposing different particle concentrations in these reservoirs, the system can be maintained under controlled non-equilibrium conditions. Previous stochastic approaches have revealed an unexpected property of the system's state trajectory, namely that it remains time-reversible even when the system is driven out of equilibrium. In the absence of relevant experimental evidence, we employ microscopic molecular dynamics simulations to assess the validity of this surprising result. Remarkably, the simulation results unambiguously confirm the prediction of the stochastic analysis.