Classical treatment of the Franson two-photon correlation experiment

Abstract

A two-photon correlation experiment that was proposed by Franson [Phys. Rev. Lett. 62, 2205 (1989)] and was recently carried out is analyzed in terms of electromagnetic waves in order to see whether the observed fourthorder interference effects can be explained classically. The conclusion is that, although a classical field can give rise to such interference effects, no classical field can actually account for the observations reported.