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QI: Fachverband Quanteninformation
QI 32: Quantum Sensing and Metrology
QI 32.5: Talk
Friday, March 22, 2024, 10:45–11:00, HFT-FT 131
Activation of metrologically useful genuine multipartite entanglement — •Róbert Trényi1,2,3, Árpád Lukács1,4,3, Paweł Horodecki5,6, Ryszard Horodecki5, Tamás Vértesi7, and Géza Tóth1,2,8,3 — 1Dept. of Th. Phys., UPV, Bilbao, Spain — 2DIPC, San Sebastián, Spain — 3Wigner RCP, Budapest, Hungary — 4Dept. of Math. Sci., Durh. Univ., UK — 5Int. Cnt. for Theory of Quant. Tech., UG, Gdansk, Poland — 6Fac. of Appl. Phys. and Math., Nat. Quant. Inf. Cnt., GUT, Gdansk, Poland — 7Inst. for Nucl. Research, Debrecen, Hungary — 8IKERBASQUE, Bilbao, Spain
Quantum states with metrologically useful genuine multipartite entanglement (GME) outperform all states without GME in metrology. States reaching the maximal utility in metrology all belong to this convex set of quantum states. With our proposed scheme, we can identify a broad class of practically important states that possess metrologically useful GME in the case of several copies, even though in the single copy case these states can be non-useful, i.e., not more useful than separable states. Thus, we essentially activate quantum metrologically useful GME. Moreover, the maximal metrological usefulness is reached exponentially fast with the number of copies and the necessary measurements are just simple correlation observables. We also provide examples of states not living in the above mentioned class that improve their usefulness. Our scheme can also be used to protect certain quantum states against certain types of errors without the use of full-fledged quantum error correction techniques.
Keywords: quantum metrology; activation; genuine multipartite entanglement; Fisher information