Open AccessBehavior-dependent critical dynamics in collective states of active particles
Author(s) -
Robert C. Löffler,
Tobias Bäuerle,
Mehran Kardar,
Christian M. Rohwer,
Clemens Bechinger
Publication year - 2021
Publication title -
europhysics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.625
H-Index - 165
eISSN - 1286-4854
pISSN - 0295-5075
DOI - 10.1209/0295-5075/ac0c68
Subject(s) - symmetry breaking , bifurcation , dynamics (music) , statistical physics , physics , hysteresis , collective behavior , symmetry (geometry) , relaxation (psychology) , order (exchange) , condensed matter physics , classical mechanics , nonlinear system , mathematics , quantum mechanics , economics , psychology , social psychology , geometry , finance , sociology , anthropology , acoustics
We experimentally demonstrate critical collective behavior in a system of active colloidal particles (APs), achieved through variations of their mutual interactions using feedback control. At the transition between a swarm and a swirl we observe an explicit bifurcation dynamics of the rotational order parameter and a critical slowing down, i.e. , a growth of the relaxation time by almost one order of magnitude. Additional signatures of critical dynamics, including hysteresis in presence of symmetry-breaking particle interactions, and a maximum of the susceptibility, are measured and characterized in terms of a theoretical model which is based purely on the time-reversal symmetry of the order parameter.