From single-particle to collective effective temperatures in an active fluid of self-propelled particles Auteur(s): Levis D., Berthier L. (Article) Publié: Europhysics Letters (Epl), vol. 111 p.60006 (2015) Texte intégral en Openaccess : Ref HAL: hal-01229483_v1 Ref Arxiv: 1506.08553 DOI: 10.1209/0295-5075/111/60006 WoS: 000364539400006 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 52 Citations Résumé: We present a comprehensive analysis of effective temperatures based on fluctuation-dissipation relations in a model of an active fluid composed of self-propelled hard disks. We first investigate the relevance of effective temperatures in the dilute and moderately dense fluids. We find that a unique effective temperature does not in general characterize the non-equilibrium dynamics of the active fluid over this broad range of densities, because fluctuation-dissipation relations yield a lengthscale-dependent effective temperature. By contrast, we find that the approach to a non-equilibrium glass transition at very large densities is accompanied by the emergence of a unique effective temperature shared by fluctuations at all lengthscales. This suggests that an effective thermal dynamics generically emerges at long times in very dense suspensions of active particles due to the collective freezing occurring at non-equilibrium glass transitions. Commentaires: 6 pages, 3 figs. Réf Journal: EPL 111, 60006 (2015) |