Critical mingling and universal correlations in model binary active liquids

TL;DR

This paper investigates a minimal model of active particles moving in opposite directions, revealing a critical phase transition, universal algebraic correlations, and underlying hydrodynamic mechanisms responsible for collective behaviors.

Contribution

It introduces a minimal model showing a critical transition and universal correlations in active binary liquids, supported by a hydrodynamic theory explaining these phenomena.

Findings

Identified a critical phase transition between mingled and lane states.

Discovered algebraic structural correlations in the mingled state.

Developed a hydrodynamic theory explaining long-range correlations.

Abstract

Ensembles of driven or motile bodies moving along opposite directions are generically reported to self-organize into strongly anisotropic lanes. Here, building on a minimal model of self-propelled bodies targeting opposite directions, we first evidence a critical phase transition between a mingled state and a phase-separated lane state specific to active particles. We then demonstrate that the mingled state displays algebraic structural correlations also found in driven binary mixtures. Finally, constructing a hydrodynamic theory, we single out the physical mechanisms responsible for these universal long-range correlations typical of ensembles of oppositely moving bodies.