Hydrodynamics of passive and active rods in a temperature gradient

TL;DR

This paper investigates how temperature gradients influence the collective dynamics of passive and active rods in two dimensions, combining experiments, simulations, and hydrodynamic theory to understand their steady-state behavior and stability.

Contribution

It introduces a coarse-grained hydrodynamic model for active and passive rods under temperature gradients, advancing understanding of their collective behavior and stability in non-uniform thermal environments.

Findings

Temperature gradients induce directed motion of rods.

Active rods exhibit altered stability and collective patterns.

Passive rods respond differently to temperature gradients compared to active ones.

Abstract

Temperature plays a very important role in various biological processes like the evolution of life, as it is anticipated that early life existed in a very hot environment that eventually cooled down with time. In vitro experiments, conducted with various active matter systems in anisotropic temperature environments, show several interesting outcomes. Motivated by these experiments and some simulation results, we study the collective behavior of self-propelled hard rods with excluded volume interactions, moving on a substrate in two dimensions and subjected to a small but finite external temperature gradient. Using a coarse-grained hydrodynamic approach, we explore the behavior of the system in the steady state and the stability both in the passive and active limits.