### Sriram Ganeshan

###
(City College of New York)

## Odd viscosity in two-dimensional hydrodynamics

In everyday fluids, the viscosity is resistance to flow and is
dissipative. However, a quantum Hall (QH) fluid at zero temperature
only has non-dissipative viscosity dubbed `odd-viscosity.' In this
talk, I will present observable consequences of the parity-violating
odd-viscosity term in classical incompressible 2+1D hydrodynamics. For
boundary conditions depending on the velocity field (flow) alone we
show that: (i) The fluid flow quantified by the velocity field is
independent of odd viscosity, (ii) The force acting on a closed contour
is independent of odd viscosity, and (iii) The odd viscosity part of
torque on a closed contour is proportional to the rate of change of
area enclosed by the contour with the proportionality constant being
twice the odd viscosity. The last statement allows us to define a
measurement protocol of “odd viscostance” in analogy to Hall resistance
measurements. We also consider no-stress boundary conditions which
explicitly depend on odd viscosity. I will discuss effects of odd
viscosity in hydrodynamics problems with no-stress boundary conditions,
namely, bubble in a planar Stokes flow and dispersing surface waves of
a broken parity fluid connecting it back to the quantum Hall case.