Isolating noise and amplifying signal with quantum Cheshire cat

TL;DR

This paper presents a thought experiment demonstrating how quantum properties like polarization can be separated and amplified from their objects, even in noisy conditions, extending the quantum Cheshire cat concept.

Contribution

It introduces a novel interferometric setup for dissociating and amplifying quantum properties, including in noisy scenarios with spin-orbit interactions.

Findings

Properties can be separated and amplified from the object.

The setup works in noisy, confused scenarios.

Signal amplification is achieved through dissociation.

Abstract

The so-called quantum Cheshire cat is a phenomenon in which an object, identified with a "cat", is dissociated from a property of the object, identified with the "grin" of the cat. We propose a thought experiment, similar to this phenomenon, with an interferometric setup, where a property (a component of polarization) of an object (photon) can be separated from the object itself and can simultaneously be amplified when it is already decoupled from its object. We further show that this setup can be used to dissociate two complementary properties, e.g., two orthogonal components of polarization of a photon and identified with the grin and the snarl of a cat, from each other and one of them can be amplified while being detached from the other. Moreover, we extend the work to a noisy scenario, effected by a spin-orbit-coupling -like additional interaction term in the Hamiltonian for the measurement process, with the object in this scenario being identified with a so-called confused Cheshire cat. We devise a gedanken experiment in which such a "confusion" can be successfully dissociated from the system, and we find that the dissociation helps in the amplification of signals.