Enhanced Estimation of Quantum Properties with Common Randomized Measurements

Journal Article · 28 March 2024 · PRX Quantum

DOI: https://doi.org/10.1103/PRXQuantum.5.010352 · OSTI ID:2329560

Vermersch, Benoît ; Rath, Aniket; Sundar, Bharathan ; Branciard, Cyril ; Preskill, John; Elben, Andreas

We present a technique for enhancing the estimation of quantum state properties by incorporating approximate prior knowledge about the quantum state. This consists in performing randomized measurements on a quantum processor and comparing the results with those obtained from a classical computer that stores an approximation of the quantum state. We provide unbiased estimators for expectation values of multicopy observables and present performance guarantees in terms of variance bounds that depend on the prior knowledge accuracy. We demonstrate the effectiveness of our approach through experimental and numerical examples detecting mixed-state entanglement, and estimating polynomial approximations of the von Neumann entropy and state fidelities. Published by the American Physical Society 2024

• Research Organization: California Institute of Technology (CalTech), Pasadena, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)
• Grant/Contract Number: NA0003525; SC0020290
• OSTI ID: 2329560
• Journal Information: PRX Quantum, Journal Name: PRX Quantum Journal Issue: 1 Vol. 5; ISSN 2691-3399; ISSN PQRUAG
• Publisher: American Physical SocietyCopyright Statement
• Country of Publication: United States
• Language: English