Metrological detection of entanglement generated by non-Gaussian operations

TL;DR

This paper introduces a practical Fisher information-based protocol for detecting non-Gaussian entanglement, specifically photon-subtracted states, using homodyne detection, which is crucial for quantum computing and information protocols.

Contribution

It presents a new, resource-efficient method for witnessing non-Gaussian entanglement in photon-subtracted states, enhancing experimental feasibility.

Findings

Protocol effectively detects non-Gaussian entanglement

Feasible with current homodyne detection technology

Applicable to states generated by multiple photon subtraction

Abstract

Entanglement and non-Gaussianity are physical resources that are essential for a large number of quantum-optics protocols. Non-Gaussian entanglement is indispensable for quantum-computing advantage and outperforms its Gaussian counterparts in a number of quantum-information protocols. The characterization of non-Gaussian entanglement is a critical matter as it is in general highly demanding in terms of resources. We propose a simple protocol based on the Fisher information for witnessing entanglement in an important class of non-Gaussian entangled states: photon-subtracted states. We demonstrate that our protocol is relevant for the detection of non-Gaussian entanglement generated by multiple photon-subtraction and that it is experimentally feasible through homodyne detection.