Speaker: Monika Schleier-Smith, Stanford University
Abstract: The graph of interactions in a quantum many-body system is crucial for governing the flow of information and the structure of correlations. We engineer programmable nonlocal interactions in an array of atomic ensembles within an optical resonator, where photons convey information between distant atomic spins. In our system of spin-1 atoms, the photon-mediated interactions manifest in the formation of correlated atom pairs. For all-to-all interactions, we verify the resulting entanglement by observing spin-nematic squeezing. We furthermore achieve versatile control of the graph of interactions by programming the spectrum of an optical drive field, thereby realizing effective geometries entirely distinct from the physical geometry of the array. We apply this toolbox to explore frustrated interactions, non-trivial topologies, and an emergent treelike geometry inspired by concepts of quantum gravity.