Structural correlations in diffusiophoretic colloidal mixtures with nonreciprocal interactions

TL;DR

This paper investigates how nonreciprocal interactions in driven colloidal mixtures lead to unique nonequilibrium correlations, supported by a microscopic theory and computer simulations, with implications for experimental chemotactic colloids.

Contribution

It develops a microscopic statistical theory for nonreciprocal colloidal interactions and validates it through simulations, revealing new nonequilibrium correlation phenomena.

Findings

Nonreciprocity induces distinct pair correlations in colloids.

The theory accurately predicts correlation functions in simulations.

Results are applicable to chemotactic colloidal experiments.

Abstract

Nonreciprocal effective interaction forces can occur between mesoscopic particles in colloidal suspensions that are driven out of equilibrium. These forces violate Newton's third law actio=reactio on coarse-grained length and time scales. Here we explore the statistical mechanics of Brownian particles with nonreciprocal effective interactions. Our model system is a binary fluid mixture of spherically symmetric, diffusiophoretic mesoscopic particles, and we focus on the time-averaged particle pair- and triplet-correlation functions. Based on the many-body Smoluchowski equation we develop a microscopic statistical theory for the particle correlations and test it by computer simulations. For model systems in two and three spatial dimensions, we show that nonreciprocity induces distinct nonequilibrium pair correlations. Our predictions can be tested in experiments with chemotactic colloidal suspensions.