Dynamics of a Bose-Einstein Condensate near a Feshbach Resonance

TL;DR

This paper investigates how a Bose-Einstein condensate responds to rapid changes in interaction strength near a Feshbach resonance, focusing on collapse dynamics, quantum evaporation, and atom-molecule coherence effects.

Contribution

It provides new insights into condensate dynamics under rapid scattering length variations, highlighting the roles of quantum evaporation and atom-molecule coherence.

Findings

Collapse occurs when scattering length changes from positive to negative.

Quantum evaporation significantly affects condensate evolution.

Atom-molecule coherence influences the condensate's response.

Abstract

We discuss the response of a Bose-Einstein condensate to a change in the scattering length, which is experimentally realized by tuning the magnetic field near a Feshbach resonance. In particular, we consider the collapse of the condensate induced by a sudden change in the scattering length from a large positive to a small negative value. We also consider the condensate dynamics that results from a single pulse in the magnetic field, due to which the scattering length is rapidly increased from zero to a large value and then after some time rapidly decreased again to its initial value. We focus primarily on the consequences of the quantum evaporation process on the dynamics of the Bose-Einstein condensate, but also discuss the effects of atom-molecule coherence.