Generation of nonclassical microwave states using an artificial atom in   1D open space
  We have embedded an artificial atom, a superconducting transmon qubit, in a 1D open space and investigated the scattering properties of an incident microwave coherent state. By studying the statistics of the reflected and transmitted fields, we demonstrate that the scattered states can be nonclassical. In particular, by measuring the second-order correlation function, $g^{(2)}$, we show photon antibunching in the reflected field and superbunching in the transmitted field. We also compare the elastically and inelastically scattered fields using both phase-sensitive and phase-insensitive measurements. 
Io-Chun Hoi, Tauno Palomaki, G\"oran Johansson, Joel Lindkvist, Per   Delsing and C. M. Wilson
quant-ph