Superfluidity of Interacting Bosonic Mixtures in Optical Lattices

TL;DR

This paper investigates how interactions in a two-component bosonic mixture in an optical lattice affect superfluidity, revealing that the second component can suppress coherence near the superfluid-Mott insulator transition.

Contribution

It provides experimental evidence of interaction effects in bosonic mixtures in optical lattices, especially how a second component influences superfluid coherence near phase transitions.

Findings

Presence of a second component reduces superfluid coherence.

The effect depends on the relative populations and lattice depths.

Behavior aligns with theories of impurity scattering and atom-phonon interactions.

Abstract

We report the observation of many-body interaction effects for a homonuclear bosonic mixture in a three-dimensional optical lattice with variable state dependence along one axis. Near the superfluid-to-Mott insulator transition for one component, we find that the presence of a second component can reduce the apparent superfluid coherence, most significantly when it either experiences a strongly localizing lattice potential or none at all. We examine this effect by varying the relative populations and lattice depths, and discuss the observed behavior in view of recent proposals for scattering from impurities and of atom-phonon coupling for atoms immersed in a superfluid.