Tuesday | April 11 | 4:00 p.m. | MIT Room 26-214

Alain Aspect  (CNRS)

"The atomic Hanbury Brown and Twiss effect: a step in quantum atom optics"

Fifty years ago,  R. Hanbury Brown and R.Q. Twiss invented a new method for measuring the diameter of stars, based on the effect of "photon bunching". Their publication prompted a hot controversy about the understanding of their effect: how could photons emitted by opposite edges of a star exhibit bunching, ie lack of statistical independence? The confusion increased yet more when it was realised that laser light does NOT exhibit bunching, and it is partly for clarifying these points that R Glauber developped the formalism of modern quantum optics. This effect has more recently been observed with atoms, and we will present these recent experiments in the light of the discussions about photons, focusing on our recent experiments at Institut d'Optique.