Towards Coupling Neutral Atoms to a Superconducting Resonator at 20 mK

Recent proposals in quantum computing center on the creation of hybrid quantum processors. Here we report progress on an experiment to couple an ensemble of $^{87}$Rb atoms to a superconducting, thin-film LC resonator at 20 mK through a magnetic dipole transition. We have demonstrated tuning of the LC resonator to within 2 kHz of the 6.8GHz hyperfine splitting of $^{87}$Rb. The next step is to trap the atoms around a sub-wavelength optical fiber using a two-color, evanescent wave dipole trap. This will allow us to bring the atoms less than 10 $\mu$m above the surface of the superconductor without producing excessive heating. We seek to provide proof of principle for interfacing a stable quantum memory, the $^{87}$Rb atoms, to superconducting qubits.