Feshbach molecule formation through an oscillating magnetic field: subharmonic resonances

TL;DR

This paper investigates how sinusoidal magnetic field modulation can convert ultracold atoms into molecules near Feshbach resonances, analyzing many-body effects and experimental conditions to explain observed conversion efficiencies.

Contribution

It introduces a model that includes many-body effects and simulates experimental conditions, clarifying the dependence of molecule formation on modulation parameters and atomic density.

Findings

Conversion efficiency depends on frequency, amplitude, and duration of magnetic modulation.

Atomic density influences the saturation of atom-molecule conversion.

The model explains experimental observations and the role of many-body effects.

Abstract

The conversion of ultracold atoms to molecules via a magnetic Feshbach resonance with a sinusoidal modulation of the field is studied. Different practical realizations of this method in Bose atomic gases are analyzed. Our model incorporates many-body effects through an effective reduction of the complete microscopic dynamics. Moreover, we simulate the experimental conditions corresponding to the preparation of the system as a thermal gas and as a condensate. Some of the experimental findings are clarified. The origin of the observed dependence of the production efficiency on the frequency, amplitude, and application time of the magnetic modulation is elucidated. Our results uncover also the role of the atomic density in the dynamics, specifically, in the observed saturation of the atom-molecule conversion process.