Entropy Insights: From Lasers and Bose Condensates to Acceleration Radiation and Black Hole Emissions

Einstein's study [1] of the entropy of light led him to the photon concept. More recently, the entropy of laser light and its relation to the Bose condensate [2] (a.k.a. "the atom laser") yield interesting insights into correlation entropy [3]. Furthermore, surprising results arise from the study of the entropy of light from a beam of atoms falling into a black hole [4].