Magnetic microswimmers exhibit Bose-Einstein-like condensation

TL;DR

This paper demonstrates that magnetic microswimmers in a microfluidic channel can undergo a non-equilibrium phase transition leading to a Bose-Einstein-like condensation, revealing new classical phases of active matter.

Contribution

It introduces a generalized thermodynamic framework for active matter exhibiting Bose-Einstein-like condensation, combining analytical and simulation methods.

Findings

Microswimmers condense at the channel center via a non-equilibrium phase transition.

The effective dynamics map onto a diffusivity-edge problem.

The thermodynamic framework matches simulation results without adjustable parameters.

Abstract

We study an active matter system comprised of magnetic microswimmers confined in a microfluidic channel and show that it exhibits a new type of self-organized behavior. Combining analytical techniques and Brownian dynamics simulations, we demonstrate how the interplay of non-equilibrium activity, external driving, and magnetic interactions leads to the condensation of swimmers at the center of the channel via a non-equilibrium phase transition that is formally akin to Bose-Einstein condensation. We find that the effective dynamics of the microswimmers can be mapped onto a diffusivity-edge problem, and use the mapping to build a generalized thermodynamic framework, which is verified by a parameter-free comparison with our simulations. Our work reveals how driven active matter has the potential to generate exotic classical non-equilibrium phases of matter with traits that are analogous to those observed in quantum systems.