Extended Bose-Hubbard Models with Ultracold Magnetic Atoms

TL;DR

This paper demonstrates the realization of an extended Bose-Hubbard model using ultracold magnetic erbium atoms, revealing long-range dipolar interactions and their effects on quantum phase transitions in optical lattices.

Contribution

It introduces the experimental implementation of the extended Bose-Hubbard model with magnetic atoms, highlighting anisotropic interactions and long-range effects.

Findings

Observation of anisotropic onsite interactions

Detection of nearest-neighbor long-range interactions

Control of superfluid-to-Mott insulator transition

Abstract

The Hubbard model underlies our understanding of strongly correlated materials. While its standard form only comprises interaction between particles at the same lattice site, its extension to encompass long-range interaction, which activates terms acting between different sites, is predicted to profoundly alter the quantum behavior of the system. We realize the extended Bose-Hubbard model for an ultracold gas of strongly magnetic erbium atoms in a three-dimensional optical lattice. Controlling the orientation of the atomic dipoles, we reveal the anisotropic character of the onsite interaction and hopping dynamics, and their influence on the superfluid-to-Mott insulator quantum phase transition. Moreover, we observe nearest-neighbor interaction, which is a genuine consequence of the long-range nature of dipolar interactions. Our results lay the groundwork for future studies of novel exotic many-body quantum phases.