Only the ambidextrous can flock: Two-dimensional chiral Malthusian flocks, time cholesterics, and the Kardar-Parisi-Zhang equation
Leiming Chen, Chiu Lee, John Toner (2026) Only the ambidextrous can flock: Two-dimensional chiral Malthusian flocks, time cholesterics, and the Kardar-Parisi-Zhang equation Phys Rev E (IF: 2.5) 113(4-2) 045419Abstract
We study the hydrodynamic behavior of two-dimensional chiral dry Malthusian flocks, that is, chiral polar-ordered active matter with neither number nor momentum conservation. We show that, in the absence of fluctuations, such systems generically form a "time cholesteric," in which the velocity of the entire system rotates uniformly at a fixed frequency b. Fluctuations about this state belong to the universality class of (2+1)-dimensional Kardar-Parisi-Zhang (KPZ) equation, which implies short-ranged orientational order in the hydrodynamic limit. We then show that, in the limit of weak chirality, the hydrodynamics of a system with reasonable size is expected to be governed by the linear regime of the KPZ equation, exhibiting quasi-long-ranged orientational order. Our predictions for the velocity and number density correlations are testable in both simulations and experiments.
Links
http://www.ncbi.nlm.nih.gov/pubmed/42141653http://dx.doi.org/10.1103/sj5y-8dsd
Similar articles
Tools
