Quantum-statistics-induced flow patterns in driven ideal Fermi gases

TL;DR

This paper investigates the complex flow patterns, including vorticity and antiferromagnetic correlations, that emerge in driven ideal Fermi gases due to quantum statistics, revealing phenomena absent in classical noninteracting particles.

Contribution

It introduces a detailed analysis of flow patterns in ideal Fermi gases under strong driving, highlighting quantum statistical effects on vorticity and magnetic correlations.

Findings

Complex vorticity patterns emerge in steady state.

Short-range antiferromagnetic vorticity correlations are predicted.

Detectable magnetic moments of the order of a tenth of a magneton are identified.

Abstract

While classical or quantum interacting liquids become turbulent under sufficiently strong driving, it is not obvious what flow pattern an ideal quantum gas develops under similar conditions. Unlike classical noninteracting particles which exhibit rather trivial flow, ideal fermions have to satisfy the exclusion principle, which acts as a form of collective repulsion. We thus study the flow of an ideal Fermi gas as it is driven out of a narrow orifice of width comparable to the Fermi wavelength, employing both a microcanonical approach to transport, and solving a Lindblad equation for Markovian driving leads. Both methods are in good agreement and predict an outflowing current density with a complex microscopic pattern of vorticity in the steady state. Applying a bias of the order of the chemical potential results in a short-range correlated antiferromagnetic vorticity pattern, corresponding to local moments of the order of a tenth of a magneton, $e\hbar/2m$, if the fermions are charged. The latter may be detectable by magnetosensitive spectroscopy in strongly driven cold gases (atoms) or clean electronic nanostructures (electrons).