Dense polar active fluids in a disordered environment

TL;DR

This paper investigates how quenched disorder affects the flocking transition in dense polar active fluids, revealing a new universality class governed by a quenched Navier-Stokes fixed point through renormalization group analysis.

Contribution

It introduces a novel universality class for the disorder-driven flocking transition in active matter, unifying different types of quenched disorder under a common framework.

Findings

Disorder induces a continuous flocking transition with unique scaling behavior.

Both random force and dilution disorders belong to the same universality class.

Critical exponents are determined via perturbative renormalization group analysis.

Abstract

We examine the influence of quenched disorder on the flocking transition of dense polar active matter. We consider incompressible systems of active particles with aligning interactions under the effect of either quenched random forces or random dilution. The system displays a continuous disorder-order (flocking) transition, and the associated scaling behavior is described by a new universality class which is controlled by a quenched Navier-Stokes fixed point. We determine the critical exponents through a perturbative renormalization group analysis. We show that the two forms of quenched disorder, random force and random mass (dilution), belong to the same universality class, in contrast with the situation at equilibrium.