Universality in Driven and Equilibrium Hard Sphere Liquid Dynamics

TL;DR

This paper introduces a power functional theory that explains the universal dynamics of driven and equilibrium hard sphere liquids, capturing superadiabatic forces like drag and viscosity with quantitative accuracy.

Contribution

It presents a novel power functional framework that predicts superadiabatic forces in hard sphere liquids, unifying driven and equilibrium dynamics.

Findings

Power functional theory accurately predicts superadiabatic forces.

Universal force fields are observed across different liquid systems.

Quantitative agreement with Brownian dynamics simulations.

Abstract

We demonstrate that the time evolution of the van Hove dynamical pair correlation function is governed by adiabatic forces that arise from the free energy and by superadiabatic forces that are induced by the flow of the van Hove function. The superadiabatic forces consist of drag, viscous, and structural contributions, as occur in active Brownian particles, in liquids under shear and in lane forming mixtures. For hard sphere liquids we present a power functional theory that predicts these universal force fields in quantitative agreement with our Brownian dynamics simulation results.