Vanishing Bulk Viscosities and Conformal Invariance of the Unitary Fermi Gas
Dam Thanh Son
By requiring general-coordinate and conformal invariance of the hydrodynamic equations, we show that the unitary Fermi gas has zero bulk viscosity, $\ensuremath{\zeta}=0$, in the normal phase. In the superfluid phase, two of the bulk viscosities have to vanish, ${\ensuremath{\zeta}}_{1}={\ensuremath{\zeta}}_{2}=0$, while the third one ${\ensuremath{\zeta}}_{3}$ is allowed to be nonzero.
arXiv:cond-mat/0511721•Physical Review Letters•Jan 11, 2007•141 citations