Degenerate Bose-Bose mixture in a three-dimensional optical lattice

TL;DR

This study investigates a heteronuclear Bose-Bose mixture of rubidium and potassium in a 3D optical lattice, revealing how interspecies interactions influence the effective mass and interference patterns.

Contribution

It provides experimental evidence of interspecies interaction effects on a Bose-Bose mixture in a 3D optical lattice, highlighting the role of effective mass increase.

Findings

Disappearance of interference pattern for $^{87}$Rb with lattice depth increase

Shift of interference pattern towards shallower lattice depths due to $^{41}$K presence

Comparison with Fermi-Bose mixtures suggests interspecies interactions affect effective mass

Abstract

We produce a heteronuclear quantum degenerate mixture of two bosonic species, $^{87}$Rb and $^{41}$K, in a three-dimensional optical lattice. On raising the lattice barriers, we observe the disapperance of the inference pattern of the heavier $^{87}$Rb, shifting toward shallower lattice depths in the presence of a minor fraction of $^{41}$K. This effect is sizable and requires only a marginal overlap between the two species. We compare our results with similar findings reported for Fermi-Bose mixtures and discuss the interpretation scenarios proposed to date, arguing that the explanation may be linked to the increased effective mass due to the interspecies interactions.