Delayed choice of paths selected by grin and snarl of quantum Cheshire Cat

Abstract

The quantum Cheshire Cat is a mysterious phenomenon that temporarily strips a system -a "cat" -of its property -its "grin". A corollary of this effect is the decoupling of two properties of the same system, which we call the grin and the snarl. This can in principle be realized by detecting two components of polarization of a photon in two different arms of an interferometer. We introduce a mechanism by which we can interchange the positions of these two properties. By doing this we uncover a phenomenon that decouples the grin and the snarl, and puts them in their place even before they encounter the mechanism.