2021/05/13 by Kateřina Jiráková, Jiráková, Kateřina, Artur Barasiński +7 · 1 citation
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2105.06274
openalex publication_date 2021/05/13 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
The genuine concurrence is a standard quantifier of multipartite\nentanglement, detection and quantification of which still remains a difficult\nproblem from both theoretical and experimental point of view. Although many\nefforts have been devoted toward the detection of multipartite entanglement\n(e.g., using entanglement witnesses), measuring the degree of multipartite\nentanglement, in general, requires some knowledge about an exact shape of a\ndensity matrix of the quantum state. An experimental reconstruction of such\ndensity matrix can be done by full state tomography which amounts to having the\ndistant parties share a common reference frame and well calibrated devices.\nAlthough this assumption is typically made implicitly in theoretical works,\nestablishing a common reference frame, as well as aligning and calibrating\nmeasurement devices in experimental situations are never trivial tasks. It is\ntherefore an interesting and important question whether the requirements of\nhaving a shared reference frame and calibrated devices can be relaxed. In this\nwork we study both theoretically and experimentally the genuine concurrence for\nthe generalized Greenberger-Horne-Zeilinger states under randomly chosen\nmeasurements on a single qubits without a shared frame of reference and\ncalibrated devices. We present the relation between genuine concurrence and\nso-called nonlocal volume, a recently introduced indicator of nonlocality.\n