Towards superconducting-cavity-induced spin squeezing in a neutral Rubidium-85 atom ensemble

Cavity-mediated spin-squeezing has been used for enhanced quantum sensing capabilities for over two decades. High cooperativity–the measure for the coupling of the atoms and the cavity compared with the dissipative loss processes–is essential to generate highly squeezed states. Optical cavities use the homogeneity and long coherence times of neutral atoms towards this goal. While optical cavities leverage the long coherence times and homogeneity of neutral atoms, they typically exhibit lower cooperativity than superconducting cavities at RF frequencies. Here, we report our progress in using our hybrid millimeter wave (mmwave) and optical cavity setup to leverage the combined advantages of superconducting cavities and atomic platforms toward the generation of spin-squeezed states. In particular, we use the Rydberg-dressed energy levels of a neutral Rubidium-85 atomic ensemble along with a cryogenic superconducting mmwave cavity to prepare the collective spin state. The strong, unitary interactions mediated by our platform will allow us to generalize our capabilities for state preparation of highly non-classical states, like the Greenberger–Horne–Zeilinger (GHZ) state, which are of particular interest in quantum simulation and computing.