Quantum turbulence, superfluidity, non-Markovian dynamics, and wave function thermalization

TL;DR

This paper investigates the non-Markovian dynamics and thermalization process of quantum turbulence in a unitary Fermi gas, revealing how vortex tangles evolve and lead to thermal equilibrium.

Contribution

It introduces a unified theoretical framework to study the non-equilibrium evolution and thermalization of quantum turbulence in a unitary Fermi gas.

Findings

Vortex tangles evolve through reconnections and Kelvin wave excitations.

Thermalization occurs very slowly after complex vortex dynamics.

Non-Markovian evolution is key to understanding the process.

Abstract

While quantum turbulence has been addressed both experimentally (predominantly for superfluid $^4$He and $^3$He) and theoretically, the dynamics of various ensembles of quantized vortices was followed in time only until the vortices decay into phonons. How this ``thermalization'' is achieved is still an unaddressed and thus an unelucidated question. The Unitary Fermi Gas (UFG) is a unique quantum system, which has no classical counterpart and of relevance to neutron stars, cold atoms, condensed matter and nuclear many-body systems. The non-Markovian evolution of an isolated UFG is put in evidence and its entire non-equilibrium evolution can be studied theoretically within a unified theoretical framework. The initial lattice of quantum vortices and anti-vortices evolves through a couple of vortex tangles and excitation of Kelvin waves, where vortices cross and reconnect, until very slowly thermalization sets in.