Monday·June 13, 2022

On the Gravitational Wave to Matter Coupling of Superfluid Fermi Gases Near Unitarity

Scott Lawrence🇺🇸 · Paul Romatschke🇺🇸

It is well known that gravitational waves distort equilibrium matter globally, making them amenable to detection with laser interferometers. Less well known is the fact that gravitational waves create local non-equilibrium stresses inside matter, which could conceivably lead to alternative detection methods. The gravitational wave to matter coupling $\kappa$ is a transport coefficient depending on the material, and is poorly known for most substances. In the present work, we calculate $\kappa$ for a superfluid Fermi gas near unitarity using large-$N$ techniques, finding $\kappa =\frac{n}{12m}$, with $n$ the number density and $m$ the mass of the fermion, matching the result for free Dirac fermions at zero temperature. Our prediction is amenable to non-perturbative theoretical as well as experimental tests.