Continuous Generation and Stabilization of Mesoscopic Field Superposition States in a Quantum Circuit

TL;DR

This paper presents a method to continuously generate and stabilize Schrödinger cat states in a quantum cavity using engineered dissipation, advancing quantum state control for quantum computing.

Contribution

It introduces a novel dissipation engineering scheme for the autonomous stabilization of mesoscopic superposition states in circuit QED.

Findings

Successfully stabilizes Schrödinger cat states against photon decay.

Provides analytic expressions for stabilization rates and physical quantities.

Demonstrates potential for universal quantum computation.

Abstract

While dissipation is widely considered as being harmful for quantum coherence, it can, when properly engineered, lead to the stabilization of non-trivial pure quantum states. We propose a scheme for continuous generation and stabilization of Schr\"{o}dinger cat states in a cavity using dissipation engineering. We first generate non-classical photon states with definite parity by means of a two-photon drive and dissipation, and then stabilize these transient states against single-photon decay. The single-photon stabilization is autonomous, and is implemented through a second engineered bath, which exploits the photon number dependent frequency-splitting due to Kerr interactions in the strongly dispersive regime of circuit QED. Starting with the Hamiltonian of the baths plus cavity, we derive an effective model of only the cavity photon states along with analytic expressions for relevant physical quantities, such as the stabilization rate. The deterministic generation of such cat states is one of the key ingredients in performing universal quantum computation.