Bose-Einstein condensate collapse: a comparison between theory and experiment

TL;DR

This paper numerically analyzes Bose-Einstein condensate collapse using the Gross-Pitaevskii equation and compares the results with JILA experiments, highlighting quantitative differences and discussing possible quantum effects.

Contribution

It provides a detailed comparison between mean-field theory predictions and experimental results, identifying specific discrepancies in collapse dynamics.

Findings

Predicted critical atom number exceeds experimental values.

Collapse times predicted are longer than observed.

Quantum effects like fragmentation may explain discrepancies.

Abstract

We solve the Gross-Pitaevskii equation numerically for the collapse induced by a switch from positive to negative scattering lengths. We compare our results with experiments performed at JILA with Bose-Einstein condensates of Rb-85, in which the scattering length was controlled using a Feshbach resonance. Building on previous theoretical work we identify quantitative differences between the predictions of mean-field theory and the results of the experiments. Besides the previously reported difference between the predicted and observed critical atom number for collapse, we also find that the predicted collapse times systematically exceed those observed experimentally. Quantum field effects, such as fragmentation, that might account for these discrepancies are discussed.