"Many-body quantum systems built from atoms and light."
By placing ultracold atoms within an optical cavity, we couple a many-body quantum system with a single mode of light. This light serves a dual role, both as “force carrier” that drives the atoms coherently, and also as an information carrier that by which we can measure the quantum system, potentially in vivo. I will discuss experiments performed on optical cavities containing either large atomic ensembles or mesoscopic atomic systems constructed atom-by-atom using optical tweezer arrays. In one experiment, we identify within our system all elements of a closed-loop feedback circuit and demonstrate how this system autonomously stabilizes the collective spin of an atomic ensemble. Sensitivity to single atomic spins enables mid-circuit measurement on an atom tweezer array, a prelude to error correction within a quantum information processor. Lastly, we explore the collective optical response of a structured array of atoms, demonstrating super- and sub-radiant Rayleigh scattering. This collective optical response sets the stage for experiments on light-mediated forces and a quantum-gas-microscope approach to studying phase transitions in open quantum systems.
