Minimum entropy production by microswimmers with internal dissipation

Abstract

The energy dissipation and entropy production by self-propelled microswimmers differ profoundly from passive particles pulled by external forces. The difference extends both to the shape of the flow around the swimmer, as well as to the internal dissipation of the propulsion mechanism. Here we derive a general theorem that provides an exact lower bound on the total, external and internal, dissipation by a microswimmer. The problems that can be solved include an active surface-propelled droplet, swimmers with an extended propulsive layer and swimmers with an effective internal dissipation. We apply the theorem to determine the swimmer shapes that minimize the total dissipation while keeping the volume constant. Our results show that the entropy production by active microswimmers is subject to different fundamental limits than the entropy production by externally driven particles.

Nonreciprocal collective dynamics in a mixture of phoretic Janus colloids

“…For two species, where the stability analysis shows all modes to be unstable, we speculate a state with interacting defects. Our work can be generalized in several ways-to multicomponent mixtures interacting with several substrates [20], coupling the mixture to a momentum-conserving fluid [75,76], dynamics at an interfaces and close to boundaries [77][78][79][80], and entropy production [81,82]. Several aspects of our work can be to other versions of tactic systems-whether it is phototaxis [60,83] or quorum sensing [84].…”