A Two-Atom Picture of Coherent Atom-Molecule Quantum Beats

TL;DR

This paper presents a simple two-atom model to describe coherent atom-molecule quantum beats in a Bose-Einstein condensate near a Feshbach resonance, connecting theoretical predictions with experimental observations.

Contribution

It introduces a two-atom model that approximates many-atom condensate behavior during magnetic field ramps near a Feshbach resonance.

Findings

Model reproduces experimental atom-molecule conversion fractions

Scaling trap frequency aligns model with experimental densities

Sudden approximation effectively captures magnetic field ramp dynamics

Abstract

A simple two-atom model is shown to describe a Bose-Einstein condensate of alkali atoms subjected to external magnetic field ramps near a Feshbach resonance. The implications uncovered for two atoms in a trap can be applied at least approximately to a many-atom condensate. A connection to observations is accomplished by scaling the trap frequency to achieve a density comparable to that of the experiments, which yields the fraction of atom pairs in the gas that become molecules. A sudden approximation is used to model the external magnetic field ramps in the vicinity of a two-body Feshbach resonance. The results of this model are compared with recent experimental observations of Donley et al. [1].