The Physics of 2 != 1+1

          @misc{ scivideos_PIRSA:06070051,
            doi = {10.48660/06070051},
            url = {https://pirsa.org/06070051},
            author = {Shih, Yanhau},
            keywords = {},
            language = {en},
            title = {The Physics of 2 != 1+1},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2006},
            month = {jul},
            note = {PIRSA:06070051 see, \url{https://scivideos.org/pirsa/06070051}}
          }
          

Abstract

Feynman was probably correct to say that the only mystery of quantum mechanics is the principle of superposition. Although we may never know which slit a photon has been passing in a Young’s double-slit experiment, we do have a corresponding classical concept in classical electromagnetic theory: the superposition of electromagnetic fields at a local space-time point is a solution of the Maxwell equations. In the case of joint photo-detection measurement of two photons, however, the superposition involves the addition of two-photon amplitudes, different yet indistinguishable alternatives resulting in a click-click joint photo-detection event. There is no counterpart of such concept in classical electromagnetic theory and the superposition may happen at distance. It is the two-photon superposition responsible for the mysteries of EPR by means of reality and causality. This talk will analyze the physics of based on several recent experiments.