Quantum Cafe: Ana Marie Rey

Title: Observation of itinerant magnetism in polar molecule confined in optical lattices

Abstract: Photon mediated interactions in polar molecules give rise to strong long-range and anisotropic dipolar interactions. Dipolar interactions provide opportunities for the exploration of a wider range of many-body phenomena which remain difficult to manifest and probe in systems with just contact interactions. One such phenomenon falls under the general heading of itinerant quantum magnetism, where magnetic moments (spins) interact with one another  with  coupling strength J as they hop in a periodic potential at a rate t. Their dynamics is described by the so-called t-J model,  a model originally emerging  from the large interaction energy expansion of the Hubbard Model, which is believed to describe the fundamental physics  behind  high Temperature superconductors.  In this talk I plan to report on the first realization of a generalized t-J spin model with dipolar interactions using a system of ultracold fermionic molecules with a spin-1/2 encoded in the two lowest rotational states. Our  observations are supported by theory models established in different motional regimes, and provide physically intuitive pictures of the dynamics. Our study paves the way for future exploration of itinerant  quantum magnetism with the tunability of molecular platforms.