Generalized rules for coherence transfer from local to global scale

Abstract

A thought experiment with the path-entangled photon pairs is suggested. Its analysis predicts elimination of local coherence even at infinitesimally weak entanglement. Local coherence turns out to be totally incompatible with entanglement. We can thus predict and name a new phenomenon,total mutual intolerance between local and global coherence. Unlike incompatible observables like position and momentum, whose expectation values can still coexist under trade-off between the respective indeterminacies, there is no coexistence between local and global coherence. This prediction, if confirmed, may open some new venues in Quantum Physics and Quantum Information theory. Key words: Bi-photon, entanglement, correlations, coherence transfer