A possible solution to the which-way problem of quantum interference

Abstract

It is commonly assumed that the observation of an interference pattern is incompatible with any information about the path taken by a quantum particle. Here we show that, contrary to this assumption, the experimentally observable effects of small polarization rotations applied in the slits of a double slit experiment indicate that individual particles passing the slits before their detection in the interference pattern are physically delocalized with regard to their interactions with the local polarization rotations. The rate at which the polarization is flipped to the orthogonal state is a direct measure of the fluctuations of the polarization rotation angles experienced by each particle. Particles detected in the interference maxima experience no fluctuations at all, indicating a presence of exactly one half of the particle in each slit, while particles detected close to the minima experience polarization rotations much larger than the local rotations, indicating a negative presence in one of the slits and a presence of more than one in the other.

7 pages, including 1 figure; improved explanation of the relation with weak values and weak measurements in the introduction

References in corpus (7)

• Anomalous Weak Values Are Proofs of Contextuality
• Pre- and post-selection, weak values, and contextuality
• Quantifying the presence of a neutron in the paths of an interferometer
• Weak values and the past of a quantum particle
• Apparent quantum paradoxes as simple interference: Quantum violation of the pigeonhole principle and exchange of properties between quantum particles
• When a negative weak value -1 plays the counterpart of a probability 1
• Proposal to observe paths superpositions in a double-slit setup