Quantum reservoir computing for photonic entanglement witnessing

TL;DR

This paper introduces a quantum reservoir computing method that efficiently witnesses quantum entanglement from experimental data without detailed system modeling, outperforming traditional techniques and adapting to noise.

Contribution

It presents a novel quantum reservoir computing approach for entanglement witnessing that requires no fine-tuning and is robust against noise and imperfections.

Findings

Outperforms conventional entanglement estimation methods

Automatically adapts to experimental noise and imperfections

Enables robust quantum feature assessment in multiparty states

Abstract

Accurately estimating properties of quantum states, such as entanglement, while essential for the development of quantum technologies, remains a challenging task. Standard approaches to property estimation rely on detailed modeling of the measurement apparatus and a priori assumptions on their working principles. Even small deviations can greatly affect reconstruction accuracy and prediction reliability. Here, we demonstrate that quantum reservoir computing embodies a powerful alternative for witnessing quantum entanglement and, more generally, estimating quantum features from experimental data. We leverage the orbital angular momentum of photon pairs as an ancillary degree of freedom to enable informationally complete single-setting measurements of their polarization. Our approach does not require fine-tuning or refined knowledge of the setup, at the same time outperforming conventional approaches. It automatically adapts to noise and imperfections while avoiding overfitting, ensuring robust reconstruction of entanglement witnesses and paving the way to the assessment of quantum features of experimental multiparty states.