Abstract
Let A and B be two atoms or, more generally, a ‘‘source’’ and a ‘‘detector’’ separated by some distance R. At t=0A is in an excited state, B in its ground state, and no photons are present. A theorem is proved that in contrast to Einstein causality and finite signal velocity the excitation probability of B is nonzero immediately after t=0. Implications are discussed.
- Received 2 September 1993
DOI:https://doi.org/10.1103/PhysRevLett.72.596
©1994 American Physical Society