Quantum Histories and Quantum Complementarity

Abstract EN

We discuss the origin of quantum complementarity using Feynman's sum-over-histories approach to Quantum Mechanics (QM).

We analyze two experimental setups introduced by W.

G.

Unruh and S.

Afshar and show how one should consistently calculate the existence of which-way information using interfering quantum histories.

Then we discuss the possible problems associated with the notion of which way information and provide an explanation why Englert-Greenberger duality relation cannot be violated experimentally if the standard QM postulates are accepted.