Photon Statistics of Propagating Thermal Microwaves
Jan Goetz, Stefan Pogorzalek, Frank Deppe, Kirill G. Fedorov, Peter Eder, Michael Fischer, F. Wulschner, E. Xie, Achim Marx, R. Gross · Physical Review Letters · 2017
In experiments with superconducting quantum circuits, characterizing the photon statistics of propagating microwave fields is a fundamental task. We quantify the n^{2}+n photon number variance of thermal microwave photons emitted from a blackbody radiator for mean photon numbers, 0.05≲n≲1.5. We probe the fields using either correlation measurements or a transmon qubit coupled to a microwave resonator. Our experiments provide a precise quantitative characterization of weak microwave states and information on the noise emitted by a Josephson parametric amplifier.