Dissipative superfluids, from cold atoms to quark matter

TL;DR

This paper investigates dissipative processes in superfluids, focusing on phonon contributions to transport properties in cold atomic gases and high-density quark matter, highlighting their dominance at low temperatures.

Contribution

It provides a comparative analysis of phonon-induced dissipation in fermionic superfluids across atomic and quark matter systems, emphasizing low-temperature behavior.

Findings

Phonons dominate bulk viscosity, shear viscosity, and thermal conductivity at low temperatures.

In cold atomic gases near unitarity, phonons significantly influence transport coefficients.

Superfluid quark matter also exhibits phonon-driven dissipation at high densities.

Abstract

Some results about dissipative processes in superfluids are presented. We focus on fermionic superfluidity and restrict our analysis to the contribution of phonons to bulk viscosity, shear viscosity and thermal conductivity. At sufficiently low temperatures phonons give the dominant contribution to the transport coefficients if all the other low energy excitation of the system are gapped. We first consider a system of cold fermionic atoms close to the unitarity limit. Then we turn to the superfluid phase of quark matter that may be realized at high baryonic density.