Active nematic gel with quenched disorder

TL;DR

This paper investigates how quenched disorder affects the defect dynamics and ordering in two-dimensional active nematic gels suspended in an incompressible fluid, revealing that fluid-induced fluctuations can diminish disorder effects.

Contribution

It introduces a hydrodynamic model for active nematics with quenched disorder and analyzes how disorder influences defect dynamics and ordering kinetics.

Findings

Disorder slows down the ordering process.

Fluid fluctuations significantly reduce the impact of quenched disorder.

Disorder effects are similar for contractile and extensile active stresses.

Abstract

With quenched disorder, we introduce two-dimensional active nematics suspended in an incompressible fluid. We write the coarse-grained hydrodynamic equations of motion for slow variables, viz. density, orientation and flow fields. The quenched disorder is introduced such that it interacts with the local orientation at every point with some strength. Disorder strength is tuned from zero to large values. We numerically study the defect dynamics and system's kinetics and find that the finite disorder slows the ordering. The presence of fluid induces large fluctuation in the orientation field, further disturbing the ordering. The large fluctuation in the orientation field due to the fluid is so dominant that it reduces the effect of the quenched disorder. We have also found that the disorder's effect is almost the same for both the contractile and extensile nature of active stresses in the system. This study can help {\color{black} to} understand the impact of quenched {\color{black} disorder} on the ordering kinetics of active gels with nematic interaction among the constituent objects.