Generation of Non-Classical Microwave Photon States in an Inductor--Capacitor Resonator Coupled to a Superconducting Flux Qubit

The quantum nature of a sub-millimeter sized superconducting inductor--capacitor (LC) resonator is been demonstrated. By employing a series of pulse sequences that induce half a cycle of vacuum Rabi oscillations, we put a single microwave photons into an LC resonator from a superconducting flux qubit. Sub-Poissonian photon number distributions obtained by the Fourier transformation of observed quantum oscillations between the $|n,e\rangle$ and $|n+1,g\rangle$ states ($n$: photon number in the resonator, $g$,$e$: qubit state) indicates the successful generation of non-classical photon states in an LC resonator.