Effective temperature of active complex matter

TL;DR

This study employs molecular dynamics simulations to explore the dynamics of active semi-flexible polymers, demonstrating that an effective temperature can describe their out-of-equilibrium behavior and align with experimental observations.

Contribution

It introduces a consistent method to measure effective temperature in active matter systems, linking simulation results with experimental data.

Findings

Effective temperature is higher than bath temperature when motor effects are uncorrelated with structural changes.

Multiple independent methods yield consistent effective temperature measurements.

The concept aids in interpreting experimental results and guides future research in active matter.

Abstract

We use molecular dynamics simulations to study the dynamics of an ensemble of interacting self-propelled semi-flexible polymers in contact with a thermal bath. Our intention is to model complex systems of biological interest. We find that an effective temperature allows one to rationalize the out of equilibrium dynamics of the system. This parameter is measured in several independent ways -- from fluctuation-dissipation relations and by using tracer particles -- and they all yield equivalent results. The effective temperature takes a higher value than the temperature of the bath when the effect of the motors is not correlated with the structural rearrangements they induce. We show how to use this concept to interpret experimental results and suggest possible innovative research directions.