Collapsing Bose-Einstein condensates beyond the Gross-Pitaevskii approximation

TL;DR

This paper investigates quantum field models of Bose-Einstein condensate collapse, comparing theoretical predictions with experimental data, and finds that quantum corrections do not significantly improve the model's accuracy over the Gross-Pitaevskii approximation.

Contribution

It introduces a coupled quantum field and Gross-Pitaevskii model for BEC collapse and evaluates its accuracy against experimental results.

Findings

Calculated collapse times are much larger than experimental measurements.

Quantum field corrections do not significantly improve the model.

Gross-Pitaevskii theory remains a good approximation.

Abstract

We analyse quantum field models of the bosenova experiment, in which $^{85}$Rb Bose-Einstein condensates were made to collapse by switching their atomic interactions from repulsive to attractive. Specifically, we couple the lowest order quantum field correlation functions to the Gross-Pitaevskii function, and solve the resulting dynamical system numerically. Comparing the computed collapse times with the experimental measurements, we find that the calculated times are much larger than the measured values. The addition of quantum field corrections does not noticeably improve the agreement compared to a pure Gross-Pitaevskii theory.