Experimental Verification of Entangled States in the Adversarial Scenario

TL;DR

This paper introduces a robust quantum state verification protocol effective in non-IID and adversarial scenarios, demonstrated through high-speed experiments, ensuring reliable fidelity certification even under malicious attacks.

Contribution

The authors develop and experimentally validate a defensive QSV protocol that remains reliable in all non-IID scenarios, including adversarial conditions, outperforming standard methods.

Findings

Standard QSV often unreliable in non-IID scenarios

Defensive QSV provides nearly tight fidelity certificates

Scheme is robust against experimental imperfections

Abstract

Efficient verification of entangled states is crucial to many applications in quantum information processing. However, the effectiveness of standard quantum state verification (QSV) is based on the condition of independent and identical distribution (IID), which impedes its applications in many practical scenarios. Here we demonstrate a defensive QSV protocol, which is effective in all kinds of non-IID scenarios, including the extremely challenging adversarial scenario. To this end, we build a high-speed preparation-and-measurement apparatus controlled by quantum random-number generators. Our experiments clearly show that standard QSV protocols often provide unreliable fidelity certificates in non-IID scenarios. In sharp contrast, the defensive QSV protocol based on a homogeneous strategy can provide reliable and nearly tight fidelity certificates at comparable high efficiency, even under malicious attacks. Moreover, our scheme is robust against the imperfections in a realistic experiment, which is very appealing to practical applications.