Fluctuation assisted collapses of Bose-Einstein condensates

TL;DR

This paper investigates the collapse dynamics of Bose-Einstein condensates with negative scattering length, revealing a fluctuation-assisted collapse mechanism and the significance of fluctuations and three-body loss in the process.

Contribution

The study introduces a self-consistent Gaussian state theory that properly accounts for fluctuations and three-body loss, providing new insights into collapse behavior.

Findings

Identification of a fluctuation-assisted collapse mechanism.

Significant deviation of the collapsed gas from a pure state.

Quantitative analysis of fluctuated atoms, entropy, and correlation functions.

Abstract

We study the collapse dynamics of a Bose-Einstein condensate subjected to a sudden change of the scattering length to a negative value by adopting the self-consistent Gaussian state theory for mixed states. Compared to the Gross-Pitaevskii and the Hartree-Fock-Bogoliubov approaches, both fluctuations and three-body loss are properly treated in our theory. We find a new type of collapse assisted by fluctuations which amplify the attractive interaction between atoms. Moreover, the calculation of the fluctuated atoms, the entropy, and the second-order correlation function showed that the collapsed gas was significantly deviated from a pure state.