Interaction spectroscopy of a two-component Mott insulator

Abstract

We prepare and study a two-component Mott insulator of bosonic atoms with two particles per site. The mapping of this system to a magnetic spin model and the subsequent study of its quantum phases require a detailed knowledge of the interaction strengths of the two components. In this work we use radio-frequency transitions and an on-site interaction blockade for precise empirical determination of the interaction strengths of different combinations of hyperfine states on a single lattice site. We create a map of the interactions of the two lowest hyperfine states of ⁷Li as a function of magnetic field, including measurements of several Feshbach resonances with exceptional sensitivity, and we identify promising regions for the realization of magnetic spin models.