High-Temperature Quantum Oscillations of a Non-equilibrium Non-Fermi Liquid

TL;DR

This paper reveals that non-equilibrium steady states in driven Fermi gases exhibit high-temperature quantum oscillations linked to emergent Fermi surfaces, differing significantly from traditional equilibrium oscillations.

Contribution

It demonstrates the existence of quantum oscillations in non-equilibrium Fermi gases at high temperatures, showing they behave as emergent Fermi surfaces with unique properties.

Findings

Quantum oscillations persist at high temperatures.

Oscillations are non-analytic at finite temperatures.

Temperature dependence of oscillations is non-monotonic.

Abstract

A periodically driven Fermi gas coupled to a simple boson bath reaches a non-equilibrium steady-state occupation with sharp non-analyticities at certain momenta. Here, we demonstrate that these non-analyticities behave as emergent Fermi surfaces by showing that they give rise to quantum oscillations of observables with a period controlled by the effective Fermi surface area enclosed by these non-analyticities. However, these oscillations have several striking differences with standard equilibrium quantum oscillations. For example, they remain non-analytic at finite temperatures, their amplitude can survive up to extremely high temperatures comparable to the frequency of the drive, and they can display non-monotonic temperature dependence completely at odds with standard Lifshits-Kosevich behavior.