Parity-Swap State Comparison Amplifier for Schr\"odinger Cat States

TL;DR

This paper introduces a parity-swap state comparison amplifier for Schrödinger cat states that uses Gaussian resources and simple detectors to achieve high-fidelity amplification with about twofold gain without prior state knowledge.

Contribution

It presents a novel postselecting amplifier for Schrödinger cat states that does not need the amplified state to be known beforehand, utilizing Gaussian resources and simple detection.

Findings

High-fidelity amplification achieved

Approximately twofold gain demonstrated

Operates with simple Geiger-mode photodetectors

Abstract

We propose a postselecting parity-swap amplifier for Schr\"odinger cat states that does not require the amplified state to be known a priori. The device is based on a previously-implemented state comparison amplifier for coherent states. It consumes only Gaussian resource states, which provides an advantage over some cat state amplifiers. It requires simple Geiger-mode photodetectors and works with high fidelity and approximately twofold gain.