39-K Bose-Einstein condensate with tunable interactions

TL;DR

This paper reports the creation of a 39-K Bose-Einstein condensate with tunable interactions, achieved through sympathetic cooling and magnetic Feshbach resonances, enabling studies of weakly interacting quantum gases.

Contribution

It demonstrates the production and tunability of 39-K BECs using Feshbach resonances, which was not previously achieved with this species.

Findings

Successful creation of 39-K BEC with negative scattering length

Demonstrated control of interactions via magnetic tuning

Explored stability and expansion properties of the condensate

Abstract

We produce a Bose-Einstein condensate of 39-K atoms. Condensation of this species with naturally small and negative scattering length is achieved by a combination of sympathetic cooling with 87-Rb and direct evaporation, exploiting the magnetic tuning of both inter- and intra-species interactions at Feshbach resonances. We explore tunability of the self-interactions by studying the expansion and the stability of the condensate. We find that a 39-K condensate is interesting for future experiments requiring a weakly interacting Bose gas.