Experimental study of the momentum correlation of a pseudo-thermal field   in the photon counting regime
  Thermal (or pseudo-thermal) radiation has been recently proposed for imaging and interference types of experiments to simulate entangled states. We report an experimental study on the momentum correlation properties of a pseudo-thermal field in the photon counting regime. The characterization and understanding of such a light source in the context of two photon physics, especially its similarities and differences compared to entangled two-photon states, is useful in gaining knowledge of entanglement and may help us to assess the real potential of applications of chaotic light in this context. 
Giuliano Scarcelli, Alejandra Valencia, and Yanhua Shih