Three-Photon Correlations in a Strongly Driven Atom-Cavity System
  The quantum dynamics of a strongly driven, strongly coupled single-atom-cavity system is studied by evaluating time-dependent second- and third-order correlations of the emitted photons. The coherent energy exchange, first, between the atom and the cavity mode, and second, between the atom-cavity system and the driving laser, is observed. Three-photon detections show an asymmetry in time, a consequence of the breakdown of detailed balance. The results are in good agreement with theory and are a first step towards the control of a quantum trajectory at larger driving strength. 
Markus Koch, Christian Sames, Maximilian Balbach, Haytham Chibani,   Alexander Kubanek, Karim Murr, Tatjana Wilk, and Gerhar...
quant-ph