Superadiabatic forces in Brownian many-body dynamics

TL;DR

This paper introduces a simulation method to evaluate superadiabatic forces in nonequilibrium Brownian many-body systems, revealing their significance and complexity beyond traditional adiabatic approximations.

Contribution

It presents a novel simulation approach to isolate and quantify superadiabatic correlations in Brownian dynamics, advancing understanding of out-of-equilibrium forces.

Findings

Superadiabatic forces are significant in Brownian many-body dynamics.

Out-of-equilibrium contributions are complex and crucial for accurate modeling.

The method clarifies the limitations of existing dynamical density functional theory.

Abstract

Theoretical approaches to nonequilibrium many-body dynamics generally rest upon an adiabatic assumption, whereby the true dynamics is represented as a sequence of equilibrium states. Going beyond this simple approximation is a notoriously difficult problem. For the case of classical Brownian many-body dynamics we present a simulation method that allows to isolate and precisely evaluate superadiabatic correlations and the resulting forces. Application of the method to a system of one-dimensional hard particles reveals the importance for the dynamics, as well as the complexity, of these nontrivial out-of-equilibrium contributions. Our findings help clarify the status of dynamical density functional theory and provide a rational basis for the development of improved theories.