Viscous Flow in a 1D Spin-Polarized Fermi Gas: the Role of Integrability on Viscosity

TL;DR

This paper investigates the bulk viscosity of a one-dimensional spin-polarized p-wave Fermi gas, demonstrating that integrability does not prevent finite viscosity, with calculations performed in both high- and low-temperature regimes.

Contribution

It introduces a simple microscopic model for calculating bulk viscosity in an integrable 1D Fermi gas, challenging the notion that integrability forbids dissipation.

Findings

Bulk viscosity is finite despite integrability.

Viscosity calculations are consistent with scale symmetry.

The model applies to both high- and low-temperature limits.

Abstract

The transport properties of one-dimensional Fermi gases at low-temperatures are often described by the Luttinger liquid (LL) model. However, to study dissipation one needs to examine interactions beyond the LL model. In this work we provide a simple model which allows for a direct microscopic calculation of the bulk viscosity, namely the one dimensional spin polarized p-wave Fermi gas. We calculate the bulk viscosity in both the high- and low-temperature limits. We find that the bulk viscosity is finite and consistent with the requirement of scale symmetry, in spite of the inherent integrability of the microscopic model. We argue how integrability does not forbid a finite bulk viscosity, and compare our work to previous kinetic theory calculations.