Controlling a magnetic Feshbach resonance with laser light

TL;DR

This paper demonstrates a method to control magnetic Feshbach resonances in ultracold gases using laser light near a molecular transition, enabling tunable interactions with reduced particle loss compared to traditional optical methods.

Contribution

It introduces a novel technique to shift magnetic Feshbach resonances with laser light, combining the advantages of magnetic and optical control while minimizing inelastic losses.

Findings

Laser near-resonant with molecular transition shifts Feshbach resonance

Reduced particle loss compared to optical Feshbach resonances

Enables spatial modulation of interactions in ultracold gases

Abstract

The capability to tune the strength of the elastic interparticle interaction is crucial for many experiments with ultracold gases. Magnetic Feshbach resonances are a tool widely used for this purpose, but future experiments would benefit from additional flexibility such as spatial modulation of the interaction strength on short length scales. Optical Feshbach resonances offer this possibility in principle, but suffer from fast particle loss due to light-induced inelastic collisions. Here we show that light near-resonant with a molecular bound-to-bound transition can be used to shift the magnetic field at which a magnetic Feshbach resonance occurs. This makes it possible to tune the interaction strength with laser light and at the same time induce considerably less loss than an optical Feshbach resonance would do.