Strong Magnetic Coupling of an Ultracold Gas to a Superconducting Waveguide Cavity

Placing an ensemble of 10(6) ultracold atoms in the near field of a superconducting coplanar waveguide resonator with a quality factor Q similar to 10(6), one can achieve strong coupling between a single microwave photon in the coplanar waveguide resonator and a collective hyperfine qubit state in the ensemble with g(eff)/2 pi similar to 40 kHz larger than the cavity linewidth of kappa/2 pi similar to 7 kHz. Integrated on an atomchip, such a system constitutes a hybrid quantum device, which also can be used to interconnect solid-state and atomic qubits, study and control atomic motion via the microwave field, observe microwave superradiance, build an integrated micromaser, or even cool the resonator field via the atoms.