Control of the interaction in a Fermi-Bose mixture

TL;DR

This paper demonstrates precise control over interspecies interactions in a fermionic-bosonic atomic mixture using Feshbach resonances, enabling manipulation of quantum gases for advanced applications.

Contribution

It reports the first detailed control and measurement of interspecies interactions in a 40K-87Rb mixture via magnetic tuning at a Feshbach resonance.

Findings

Observed collapse and reduced overlap due to attractive interactions

Accurately located the resonance position and width

Controlled instabilities for potential quantum gas applications

Abstract

We control the interspecies interaction in a two-species atomic quantum mixture by tuning the magnetic field at a Feshbach resonance. The mixture is composed by fermionic 40K and bosonic 87Rb. We observe effects of the large attractive and repulsive interaction energy across the resonance, such as collapse or a reduced spatial overlap of the mixture, and we accurately locate the resonance position and width. Understanding and controlling instabilities in this mixture opens the way to a variety of applications, including formation of heteronuclear molecular quantum gases.