Precision Measurements on a Tunable Mott Insulator of Ultracold Atoms

TL;DR

This paper reports precise experimental measurements on a tunable Mott insulator of ultracold atoms, exploring the superfluid-to-Mott-insulator transition and the effects of multi-body interactions beyond the standard Bose-Hubbard model.

Contribution

It provides quantitative analysis of interaction-dependent shifts in excitation spectra, extending understanding of multi-body effects in ultracold atomic systems.

Findings

Measured number-dependent spectral shifts due to multi-body interactions

Explored the limits of the Bose-Hubbard model in strong interaction regimes

Demonstrated tunability of the Mott insulator state

Abstract

We perform precision measurements on a Mott-insulator quantum state of ultracold atoms with tunable interactions. We probe the dependence of the superfluid-to-Mott-insulator transition on the interaction strength and explore the limits of the standard Bose-Hubbard model description. By tuning the on-site interaction energies to values comparable to the interband separation, we are able to quantitatively measure number-dependent shifts in the excitation spectrum caused by effective multi-body interactions.