Hanbury-Brown Twiss correlations to probe the population statistics of   GHz photons emitted by conductors
  We present the first study of the statistics of GHz photons in quantum circuits, using Hanbury-Brown and Twiss correlations. The superpoissonian and poissonian photon statistics of thermal and coherent sources respectively made of a resistor and a radiofrequency generator are measured down to the quantum regime at milliKelvin temperatures. As photon correlations are linked to the second and fourth moments of current fluctuations, this experiment, which is based on current cryogenic electronics, may become a standard for probing electron/photon statistics in quantum conductors 
Julien Gabelli, Laure-Helene Reydellet, Gwendal Feve, Jean-Marc   Berroir, Bernard Placais, Patrice Roche, Christian Glattli