'Quantum Cheshire Cat' as Simple Quantum Interference

TL;DR

This paper demonstrates that the 'Quantum Cheshire Cat' phenomenon can be explained by basic quantum interference effects, challenging the interpretation that particles are physically separated from their internal properties.

Contribution

It provides a simple quantum interference explanation for the 'Quantum Cheshire Cat' effect, clarifying misconceptions and removing apparent paradoxes from previous interpretations.

Findings

The results can be explained by quantum interference without particle-property separation.

The apparent separation in experiments is a consequence of interference effects.

The work clarifies the nature of the 'Quantum Cheshire Cat' phenomenon.

Abstract

In a recent work, Aharonov et al. suggested that a photon could be separated from its polarization in an experiment involving pre- and post-selection [New J. Phys 15, 113015 (2013)]. They named the effect 'quantum Cheshire Cat', in a reference to the cat that is separated from its grin in the novel Alice's Adventures in Wonderland. Following these ideas, Denkmayr et al. performed a neutron interferometric experiment and interpreted the results suggesting that neutrons were separated from their spin [Nat. Commun. 5, 4492 (2014)]. Here we show that these results can be interpreted as simple quantum interference, with no separation between the quantum particle and its internal degree of freedom. We thus hope to clarify the phenomenon with this work, by removing these apparent paradoxes.