Early time hydrodynamic attractor in a nearly-unitary Fermi gas

TL;DR

This paper demonstrates the emergence of hydrodynamic attractors in a nearly-unitary Fermi gas, providing insights into universal behavior in cold atomic gases and potential experimental realizations.

Contribution

It shows how the expansion-driven part of the hydrodynamic attractor appears in a nearly-unitary Fermi gas, linking theoretical models to cold atom experiments.

Findings

Hydrodynamic attractors emerge in nearly-unitary Fermi gases.

Universal behavior appears during rapid expansion.

Potential for experimental observation in cold atomic gases.

Abstract

The hydrodynamic attractors paradigm aims to explain the applicability of hydrodynamics after a very short timescale in ultra-relativistic nuclear collisions at RHIC and LHC in terms of the emergence of universal behavior across different initial states. The attractors observed in theoretical models are first driven by a rapid expansion of matter, which later gives way to the decay of exponentially damped transient excitations into the viscous fluid regime. Recently, a theoretical proposal was made how to realize hydrodynamic attractors in cold atomic gases focusing on the decay of transients and opening prospects for a future experimental realization in table top experiments. Motivated by this, in the present paper we show how the far-from-equilibrium, expansion-driven part of the hydrodynamic attractor emerges in a model of a nearly-unitary Fermi gas.