  Placing an ensemble of $10^6$ ultracold atoms in the near field of a
superconducting coplanar waveguide resonator (CPWR) with $Q \sim 10^6$ one can
achieve strong coupling between a single microwave photon in the CPWR and a
collective hyperfine qubit state in the ensemble with $g_\textit{eff} / {2 \pi}
\sim 40$ kHz larger than the cavity line width of ${\kappa}/{2 \pi} \sim 7$
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,
to study and control atomic motion via the microwave field, observe microwave
super-radiance, build an integrated micro maser or even cool the resonator
field via the atoms.
