Operational detection of Wigner negativity in arbitrary quantum states from few copies

Detection of Wigner negativity in quantum states has been made more accessible through a novel framework that utilizes moments of the Wigner function, which can be estimated from a limited number of state copies. This approach exploits constraints inherent to positive phase-space distributions, allowing for the operational detection of Wigner negativity in arbitrary quantum states. The methodology developed enables the identification of nonclassical resources that underlie quantum advantage, which is crucial for various quantum applications. As quantum developments progress, the timeline for cryptographic migration to post-quantum cryptography (PQC) narrows, increasing the urgency for PQC planning¹. The ability to detect Wigner negativity in arbitrary quantum states from few copies has significant implications for quantum information processing and quantum computing. So what matters to practitioners is that this breakthrough facilitates the identification of quantum states that can be leveraged for quantum advantage, thereby underscoring the need for prompt migration to quantum-resistant cryptographic protocols.