Characterization and control of phase fluctuations in elongated Bose-Einstein condensates

TL;DR

This paper investigates phase fluctuations in elongated Bose-Einstein condensates, demonstrating their transformation into density modulations during expansion, and explores methods to control these fluctuations for improved quantum applications.

Contribution

It provides experimental validation of phase fluctuation dynamics and introduces a theoretical approach for controlling phase via time-dependent perturbations.

Findings

Phase fluctuations transform into density modulations during time-of-flight.

Density modulations are suppressed in the trap despite phase fluctuations.

Controlling phase fluctuations can enhance precision in atom interferometry.

Abstract

Quasi one dimensional Bose-Einstein condensates (BECs) in elongated traps exhibit significant phase fluctuations even at very low temperatures. We present recent experimental results on the dynamic transformation of phase fluctuations into density modulations during time-of-flight and show the excellent quantitative agreement with the theoretical prediction. In addition we confirm that under our experimental conditions, in the magnetic trap density modulations are strongly suppressed even when the phase fluctuates. The paper also discusses our theoretical results on control of the condensate phase by employing a time-dependent perturbation. Our results set important limitations on future applications of BEC in precision atom interferometry and atom optics, but at the same time suggest pathways to overcome these limitations.