Non-reciprocal response of a two-dimensional fluid with odd viscosity

TL;DR

This paper investigates how odd viscosity in a 2D active chiral fluid causes non-reciprocal hydrodynamic responses, including non-dissipative lift forces on moving objects, revealing unique fluid behaviors due to broken symmetries.

Contribution

It derives the odd viscosity-dependent mobility tensor and demonstrates non-reciprocal responses and lift forces in a 2D active fluid with broken symmetries.

Findings

Mobility tensor depends on odd viscosity.

Non-reciprocal hydrodynamic response to point forces.

Finite-size disk experiences non-dissipative lift force.

Abstract

We discuss the linear hydrodynamic response of a two-dimensional active chiral compressible fluid with odd viscosity. The viscosity coefficient represents broken time-reversal and parity symmetries in the 2D fluid and characterizes the deviation of the system from a passive fluid. Taking into account the hydrodynamic coupling to the underlying bulk fluid, we obtain the odd viscosity-dependent mobility tensor, which is responsible for the non-reciprocal hydrodynamic response to a point force. Furthermore, we consider a finite-size disk moving laterally in the 2D fluid and demonstrate that the disk experiences a non-dissipative lift force in addition to the dissipative drag one.