title: Nonequilibrium phase transitions, fluctuations and correlations in an active contractile polar fluid.
abstract: We study the patterning, fluctuations and correlations of an active polar fluid consisting of contractile polar filaments on a two-dimensional substrate, using a hydrodynamic description. The steady states generically consist of arrays of inward pointing asters and show a continuous transition from a moving lamellar phase, a moving aster street, to a stationary aster lattice with no net polar order. We next study the effect of spatio-temporal athermal noise, parametrized by an active temperature TA, on the stability of the ordered phases. In contrast to its equilibrium counterpart, we find that the active crystal shows true long range order at low TA. On increasing TA, the asters dynamically remodel, concomitantly we find novel phase transitions characterized by bond-orientational and polar order upon "heating".
authors.affiliation: Raman Research Institute, Bangalore 560080, India.
authors.forename: Kripa
authors.initials: K
authors.lastname: Gowrishankar
authors.forename: Madan
authors.initials: M
authors.lastname: Rao
mesh_terms: D000205:Actomyosin / Q000737:chemistry*; D003599:Cytoskeleton / Q000737:chemistry*; D057446:Hydrodynamics; D007700:Kinetics; D044367:Phase Transition; D055672:Static Electricity; D013269:Stochastic Processes; D013535:Suspensions; D013696:Temperature; D013816:Thermodynamics
chemical_list: D013535:Suspensions; D000205:Actomyosin