Cool for Cats

TL;DR

This paper proposes a method to engineer environmental interactions that stabilize Schrödinger's cat states in quantum systems, potentially enhancing their use in quantum technologies and understanding quantum-classical transition.

Contribution

It introduces a novel approach to create and sustain Schrödinger's cat states by engineering system-environment interactions using double well systems and two-photon absorbers.

Findings

Steady-state near-pure Schrödinger's cat states achievable.

Prolongs lifetime of cat states against decoherence.

Applicable to quantum metrology and information processing.

Abstract

The iconic Schr\"odinger's cat state describes a system that may be in a superposition of two macroscopically distinct states, for example two clearly separated oscillator coherent states. Quite apart from their role in understanding the quantum classical boundary, such states have been suggested as offering a quantum advantage for quantum metrology, quantum communication and quantum computation. As is well known these applications have to face the difficulty that the irreversible interaction with an environment causes the superposition to rapidly evolve to a mixture of the component states in the case that the environment is not monitored. Here we show that by engineering the interaction with the environment there exists a large class of systems that can evolve irreversibly to a cat state. To be precise we show that it is possible to engineer an irreversible process so that the steady state is close to a pure Schr\"odinger's cat state by using double well systems and an environment comprising two-photon (or phonon) absorbers. We also show that it should be possible to prolong the lifetime of a Schr\"odinger's cat state exposed to the destructive effects of a conventional single-photon decohering environment. Our protocol should make it easier to prepare and maintain Schr\"odinger cat states which would be useful in applications of quantum metrology and information processing as well as being of interest to those probing the quantum to classical transition.