Molecular state in a spin-orbital-angular-momentum coupled Fermi gas

TL;DR

This paper investigates two-body bound states in a spin-orbital-angular-momentum coupled Fermi gas, revealing conditions for molecular states with quantized angular momentum and proposing detection via Raman spectroscopy, thus advancing understanding of pairing mechanisms.

Contribution

It identifies conditions for molecular state formation with finite angular momentum in SOAM-coupled Fermi gases and suggests experimental detection methods.

Findings

Molecular states with quantized angular momentum can form under SOAM coupling.

Detection of molecules via Raman spectroscopy with Laguerre-Gaussian lasers is feasible.

Molecular states can exist above the superfluid transition temperature.

Abstract

We study the two-body bound states in a spin-orbital-angular-momentum (SOAM) coupled quantum gas of fermions. Two different configurations are considered: an attractive $s$-wave interaction exists between two spin species that are SOAM coupled; and an atom with SOAM coupled internal spins interacts state-selectively with another atom. For both cases, we identify the condition for the emergence of molecular states with finite total angular momenta.These molecular states with quantized total angular momenta correspond to the SOAM-coupling-induced vortices in the corresponding Fermi superfluid. We propose to detect the molecules through Raman spectroscopy with Laguerre-Gaussian lasers. As the molecular states can form above the superfluid temperature, they offer an experimentally more accessible route toward the study of the underlying pairing mechanism under SOAM coupling.