Non-Linear Dynamics of Continuously Measured Bose-Einstein Condensates in One-Dimensional Harmonic Traps

TL;DR

This paper investigates how continuous measurements affect the dynamics of Bose-Einstein condensates in one-dimensional traps, revealing that strong interactions reduce delocalization and induce atomic bunching.

Contribution

It combines semi-analytical mean-field and quantum numerical methods to analyze measurement back action on interacting condensates, highlighting effects of strong interactions.

Findings

Atomic delocalization is smaller in strongly interacting gases.

Center-of-mass measurements induce atomic bunching.

Strong interactions can reduce the atomic cloud size below the ground-state size.

Abstract

Continuous center-of-mass position measurements performed on an interacting harmonically trapped Bose-gas are considered. Using both semi-analytical mean-field approach and completely quantum numerical technique based on positive P-representation, it is demonstrated that the atomic delocalization due to the measurement back action is smaller for a strongly interacting gas. The numerically calculated second-order correlation functions demonstrate appearance of atomic bunching as a result of the center-of-mass measurement. Though being rather small the bunching is present also for strongly interacting gas which is in contrast with the case of unperturbed gas. The performed analysis allows to speculate that for relatively strong interactions the size of atomic cloud determined with a single snapshot measurement can become smaller than the ground-state cloud size.