Heralded generation of a micro-macro entangled state

TL;DR

This paper presents a heralded optical method to generate micro-macro entangled states, specifically Schrödinger cat states, and explores their macroscopicity and potential for linking qubit and qumode processors.

Contribution

It introduces a heralded generation scheme for micro-macro entangled states using squeezed states and photon subtraction, with analysis of their macroscopicity and application in quantum information processing.

Findings

Heralded generation of micro-macro entangled states achieved.

Defined macroscopicity using phase space distance and homodyne discrimination.

Demonstrated mapping of a microscopic qubit onto a macroscopic state.

Abstract

Using different optical setups based on squeezed state and photon subtraction we show how optical entanglement between a macroscopic and a microscopic state - the so-called Schrodinger cat state or micro-macro state - can be generated. The entangled state is heralded and is thus produced a priori in contrast to previous proposals. We define the macroscopicity of the macroscopic part of the state as their mean distance in phase space and the success rate in discriminating them with homodyne detection, and subsequently, based on these measures we investigate the macroscopicity of different states. Furthermore, we show that the state can be used to map a microscopic qubit onto a macroscopic one thereby linking a qubit processor with a qumode processor.