Three-Path Quantum Cheshire Cat Observed in Neutron Interferometry
Abstract
The paradoxical phenomenon of the quantum Cheshire Cat (qCC) refers to situations where different properties of a particle appear to be localised in different paths of an interferometer and therefore spatially separated. This observation is obtained by implementing a pre- and postselection procedure. The localisations are determined qualitatively through conspicuous changes induced by weak interactions. Previous demonstrations of the qCC only used the path and spin/polarisation degrees of freedom. In addition, the present experiment uses the neutron's energy as a third property in a three-path interferometer. It is demonstrated that the three properties of neutrons are found separated in different paths in the interferometer; a detailed analysis suggests that the appearance of a property is strongly related to the geometrical relation between the state vectors of pre- and postselection with weak interactions in between. If a weak interaction in a path locally generates a state vector with a component parallel to the reference state in another path, a conspicuous intensity oscillation is expected and observed. Therefore, the appearance of the observed intensity oscillations is attributed solely to the cross-terms between the reference and the newly generated state via weak interactions.
Keywords
Cite
@article{arxiv.2303.18092,
title = {Three-Path Quantum Cheshire Cat Observed in Neutron Interferometry},
author = {Armin Danner and Niels Geerits and Hartmut Lemmel and Richard Wagner and Stephan Sponar and Yuji Hasegawa},
journal= {arXiv preprint arXiv:2303.18092},
year = {2023}
}