Spin-orbit-induced bound state and molecular signature of the degenerate Fermi gas in a narrow Feshbach resonance

TL;DR

This study investigates how spin-orbit coupling influences bound states and molecular signatures in a degenerate Fermi gas near a narrow Feshbach resonance, revealing controllable molecular fractions and shifts in critical points.

Contribution

It introduces a generalized two-channel model to analyze the effects of spin-orbit coupling on bound states and molecular signatures in a Fermi gas.

Findings

Only one bound state exists without atom-atom interactions.

Bound-state energy depends strongly on spin-orbit coupling strength.

Molecular fraction can be controlled by tuning spin-orbit coupling.

Abstract

In this paper we explore the spin-orbit-induced bound state and molecular signature of the degenerate Fermi gas in a narrow Feshbach resonance based on a generalized two-channel model. Without the atom-atom interactions, only one bound state can be found even if spin-orbit coupling exists. Moreover, the corresponding bound-state energy depends strongly on the strength of spin-orbit coupling, but is influenced slightly by its type. In addition, we find that when increasing the strength of spin-orbit coupling, the critical point at which the molecular fraction vanishes shifts from zero to the negative detuning. In the weak spin-orbit coupling, this shifting is proportional to the square of its strength. Finally, we also show that the molecular fraction can be well controlled by spin-orbit coupling.