Photon-Detector Entanglement by interference at beam splitter (Collapse and spontaneous superposition breaking)

Abstract

In this work we suggest an original, realistic and simple, form of the experiment of interference of single photon at beam splitter. Here quantum entanglement (Schrodinger cat effect) between photon and photon trajectories detector (which includes two same simple two-level systems) is studied. It admits a consistent model of the detection or measurement procedure. Concretely here (self-)collapse at detector is consistently treated as the spontaneous (non-dynamical) breaking (effective hiding) of the unitary symmetry (superposition or entanglement) of quantum mechanical dynamics. It can be considered as an especial case of the general formalism of the spontaneous symmetry breaking.