Roy Jay Glauber (born September 1, 1925) is an American theoretical physicist. He is the Mallinckrodt Professor of Physics at Harvard University and Adjunct Professor of Optical Sciences at the University of Arizona. Born in New York City, he was awarded one half of the 2005 Nobel Prize in Physics "for his contribution to the quantum theory of optical coherence ", with the other half shared by John L. Hall and Theodor W. Hänsch. In this work, published in 1963, he created a model for photodetection and explained the fundamental characteristics of different types of light, such as laser light (see coherent state ) and light from light bulbs (see blackbody ). His theories are widely used in the field of quantum optics.