Role of interactions in 87Rb-40K Bose-Fermi mixtures in a 3d optical lattice

TL;DR

This study explores how varying interspecies interactions in a 87Rb-40K Bose-Fermi mixture within a 3D optical lattice influence quantum phases, revealing asymmetries and shifts in phase transitions due to interaction tuning.

Contribution

It demonstrates the impact of tunable interspecies interactions on the superfluid to Mott insulator transition in a Bose-Fermi mixture, highlighting the role of self-trapping effects.

Findings

Asymmetry in momentum distribution between repulsive and attractive interactions

Renormalization of Bose-Hubbard parameters due to self-trapping

Shift in superfluid to Mott insulator transition with interaction strength

Abstract

We investigate the effect of interspecies interaction on a degenerate mixture of bosonic 87Rb and fermionic 40K atoms in a three-dimensional optical lattice potential. Using a Feshbach resonance, the 87Rb-40K interaction is tuned over a wide range. Through an analysis of the 87Rb momentum distribution, we find a pronounced asymmetry between strong repulsion and strong attraction. In the latter case, the Bose-Hubbard parameters are renormalized due to self-trapping, leading to a marked shift in the superfluid to Mott insulator transition with increasing Bose-Fermi interaction.