Seminario V. Vitelli
27/2/2017 ore 12
BS room Via Celoria 26
Topological sound and odd viscosity in chiral active matter
Vincenzo Vitelli (Instituut-Lorentz for Theoretical Physics, Leiden University)
Active materials are composed of interacting particles individually powered by motors. In this talk, we focus on chiral active materials that violate parity and time-reversal symmetry. First, we show how to generate topological sound in fluids of self-propelled particles exhibiting a spontaneous chiral active flow under confinement. These topological sound modes propagate unidirectionally, without backscattering, along either sample edges or domain walls and despite overdamped particle dynamics. Next, we discuss an exotic transport coefficient characteristic of quantum Hall fluids, called odd viscosity, which controls the hydrodynamics of classical fluids composed of active rotors. This odd viscosity couples pressure to vorticity leading to transverse flow in piston compression experiments. We envision that such transverse response may be exploited to design self-assembled hydraulic cranks that convert between linear and rotational motion in microscopic machines powered by active rotors fluids.