Observation of a classical cheshire cat in an optical interferometer

TL;DR

This paper replicates and extends an optical interferometry experiment claiming to demonstrate a quantum Cheshire Cat, showing that the observed effects are explainable by classical wave theory rather than quantum mechanics.

Contribution

The study reproduces and extends previous quantum Cheshire Cat experiments using an optical interferometer, demonstrating classical explanations for the observed phenomena.

Findings

The photon travels through one arm of the interferometer.

The polarization travels through the other arm.

The results are consistent with classical wave theory.

Abstract

A recent neutron interferometry experiment claims to demonstrate a paradoxical phenomena dubbed the "quantum Cheshire Cat" \cite{Denkmayr2014}. We have reproduced and extended these results with an equivalent optical interferometer. The results suggest that the photon travels through one arm of the interferometer, while its polarization travels through the other. However, we show that these experimental results belong to the domain where quantum and classical wave theories coincide; there is nothing uniquely quantum about the illusion of this cheshire cat.