Slow light and the phase of a Bose-Einstein condensate

TL;DR

This paper explores how ultra slow light interacts with a non-uniform phase in a Bose-Einstein condensate, enabling phase imprinting and measurement of phase fluctuations through light propagation.

Contribution

It demonstrates the coupling of slow light to phase gradients in a BEC and introduces a method to measure phase fluctuations via light.

Findings

Strong coupling between light and phase gradient in BEC

Phase imprinting on light from condensate

Measurement of phase fluctuations in elongated quasicondensate

Abstract

We investigate the propagation of light with ultra low group velocity in a Bose-Einstein condensate where the phase is not uniform. The light is shown to couple strongly to the phase gradient of the condensate. The interaction between the light and the condensate enables us to perform a phase imprinting where the phase of the condensate is imprinted on the light. We illustrate the effect by showing how one can measure the fluctuating phase in an elongated quasicondensate.