Optically Programmable Interactions for Cold Atoms

Optically controlled interactions are a powerful tool for studies of non-equilibrium physics in quantum simulators and can furthermore enable applications in quantum sensing and computation. I will report on experiments in which we use light to induce long-range spin interactions among cold atoms, and to tailor the interactions in space and time. By one approach, Rydberg dressing, we observe the mean-field dynamics of a transverse-field Ising model, including dynamical signatures of a paramagnetic-ferromagnetic phase transition. In a complementary platform, we demonstrate programmable long-range interactions in a millimeter-scale array of atomic ensembles within an optical resonator. Our scheme allows an arbitrary magnon dispersion relation to be specified via the modulation waveform of a control laser, opening the door to studies of frustrated magnetism and enabling explorations of quantum spin dynamics in exotic geometries and topologies.