The power of quantum information lies in its capacity to be nonlocal, encoded in correlations among entangled particles. By contrast, the interactions between particles are typically local, posing both conceptual and practical challenges in understanding, generating, and harnessing entanglement. To circumvent this bottleneck, we trap an array of atom clouds in an optical resonator that mediates effectively nonlocal interactions, letting photons act as messengers that convey information between distant sites. We have developed a versatile experimental toolbox for programming the network of interactions and correlations, and for characterizing the resulting graph of entanglement via measurements of squeezed quantum fluctuations. I will illustrate implications for advanced quantum sensing protocols and for simulating phenomena ranging from topological physics to quantum gravity. I will also discuss prospects for extending these techniques to arrays of Rydberg atoms, opening new avenues for programmable quantum simulation in strongly interacting regimes.
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