title: Spectroscopic test of bose-einstein statistics for photons.
abstract: Using Bose-Einstein-statistics-forbidden two-photon excitation in atomic barium, we have limited the rate of statistics-violating transitions, as a fraction ν of an equivalent statistics-allowed transition rate, to ν<4.0×10{-11} at the 90% confidence level. This is an improvement of more than 3 orders of magnitude over the best previous result. Additionally, hyperfine-interaction enabling of the forbidden transition has been observed, to our knowledge, for the first time.
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720-7300, USA. denglish@berkeley.edu
authors.forename: D
authors.initials: D
authors.lastname: English
authors.forename: V V
authors.initials: VV
authors.lastname: Yashchuk
authors.forename: D
authors.initials: D
authors.lastname: Budker