Atomic two-photon J = 0↔J′ = 1 transitions are forbidden for photons of the same energy. This selection rule is related to the fact that photons obey Bose-Einstein statistics. We have searched for small violations of this selection rule by studying transitions in atomic Ba. We set a limit on the probability v that photons are in exchange-antisymmetric states: v<1.2×10-7.
DeMille D., Budker D., Derr N., Deveney E. (1999). Search for Exchange-Antisymmetric Two-Photon States. Physical Review Letters, 83(20), 3978-3981.
Virtual Commons Citation
DeMille, D.; Budker, D.; Derr, N.; and Deveney, Edward (1999). Search for Exchange-Antisymmetric Two-Photon States. In Physics Faculty Publications. Paper 2.
Available at: http://vc.bridgew.edu/physics_fac/2