Double species condensate with tunable interspecies interactions

TL;DR

This paper reports the creation of a double species Bose-Einstein condensate of rubidium and potassium with tunable interactions, achieved near identified Feshbach resonances, enabling studies of complex quantum phases.

Contribution

It identifies and characterizes two interspecies Feshbach resonances in Rb-K mixtures and demonstrates tunable interactions for double species condensates.

Findings

Discovered two interspecies Feshbach resonances at 35 G and 79 G.

Created a double species condensate with tunable interactions.

Opened pathways for exploring quantum phases like Mott insulators.

Abstract

We produce Bose-Einstein condensates of two different species, $^{87}$Rb and $^{41}$K, in an optical dipole trap in proximity of interspecies Feshbach resonances. We discover and characterize two Feshbach resonances, located around 35 and 79 G, by observing the three-body losses and the elastic cross-section. The narrower resonance is exploited to create a double species condensate with tunable interactions. Our system opens the way to the exploration of double species Mott insulators and, more in general, of the quantum phase diagram of the two species Bose-Hubbard model.