Dissipation-facilitated molecules in a Fermi gas with non-Hermitian spin-orbit coupling

TL;DR

This paper investigates how non-Hermitian effects, introduced via dissipative Raman processes, enhance molecule formation in a spin-orbit-coupled Fermi gas, revealing new regimes of bound states and experimental signatures.

Contribution

It demonstrates that dissipation can facilitate molecule formation in non-Hermitian spin-orbit-coupled Fermi gases, expanding the understanding of open quantum systems.

Findings

Dissipation broadens the parameter regime for molecule formation.

Dissipative molecules have finite lifetimes but are more prevalent.

Rf spectra show shifted peaks and broadening as signatures of dissipation.

Abstract

We study the impact of non-Hermiticity on the molecule formation in a two-component spin-orbit-coupled Fermi gas near a wide Feshbach resonance. Under an experimentally feasible configuration where the two-photon Raman process is dissipative, the Raman-induced synthetic spin-orbit coupling acquires a complex strength. Remarkably, dissipation of the system facilitates the formation and binding of molecules, which, despite their dissipative nature and finite lifetime, exist over a wider parameter regime than in the corresponding Hermitian system. These dissipation-facilitated molecules can be probed by the inverse radio-frequency (rf) spectroscopy, provided the Raman lasers are blue detuned to the excited state. The effects of dissipation manifest in the rf spectra as shifted peaks with broadened widths, which serve as a clear experimental signature. Our results, readily observable in current cold-atom experiments, shed light on the fascinating interplay of non-Hermiticity and interaction in few- and many-body open quantum systems.