The hunt for the elusive photon-photon elastic scattering: the PVLAS experiment and more
by Prof. Edoardo Milotti (Dipartimento di Fisica, Università di Trieste and INFN-Sezione di Trieste)
at SMI - Boltzmanngasse 3, 1090 Wien ( 3-2-08 - Seminarraum )
by Prof. Eduardo Milotti
Dipartimento di Fisica, Università di Trieste and INFN-Sezione di Trieste
Photon-photon scattering is forbidden in classical electromagnetism, but it becomes possible in quantum field theory thanks to the fluctuations of charged matter fields. The first theoretical calculations are associated with the names of Euler, Heisenberg, and Weisskopf, and date back to more than 80 years ago, but to date a laboratory measurement is still missing. The predicted effect is extremely minute with visible photons, and measurements require an exceedingly high level of precision. Currently, a bunch of experimentalists are painstakingly trying to get to the required level of precision. There is much at stake: by reaching this difficult experimental goal we could open a new window on the nature of quantum vacuum, and maybe discover some essential clues on dark matter.
In this talk I shall briefly discuss the theoretical prediction and the current status of one experiment devoted to this difficult search (PVLAS, located in Ferrara, Italy). If time allows I shall also consider possible future developments both with visible photons and with gamma rays.