Quantum depletion of collapsing Bose-Einstein condensates

TL;DR

This study uses advanced numerical simulations to investigate quantum effects in collapsing Bose-Einstein condensates, finding that quantum fluctuations and temperature do not fully explain experimental collapse times.

Contribution

First three-dimensional numerical analysis of quantum effects in Bosenova collapse experiments, comparing methods and assessing quantum fluctuation impacts.

Findings

Collapse times are longer in simulations than experiments.

Finite temperature increases uncondensed atom creation but doesn't shorten collapse time.

Quantum fluctuations and temperature effects don't fully explain experimental discrepancies.

Abstract

We perform the first numerical three-dimensional studies of quantum field effects in the Bosenova experiment on collapsing condensates by E. Donley et al. [Nature 415, 39 (2002)] using the exact experimental geometry. In a stochastic truncated Wigner simulation of the collapse, the collapse times are larger than the experimentally measured values. We find that a finite temperature initial state leads to an increased creation rate of uncondensed atoms, but not to a reduction of the collapse time. A comparison of the time-dependent Hartree-Fock-Bogoliubov and Wigner methods for the more tractable spherical trap shows excellent agreement between the uncondensed populations. We conclude that the discrepancy between the experimental and theoretical values of the collapse time cannot be explained by Gaussian quantum fluctuations or finite temperature effects.