Optimal measurements in phase estimation: simple examples

Anno: 2016

Autori: Wasak T., Smerzi A., Pezzè L., Chwedenczuk J.

Affiliazione autori: Univ Warsaw, Inst Theoret Phys, Ul Pasteura 5, PL-02093 Warsaw, Poland;‎ INO CNR, QSTAR, Largo Enrico Fermi 2, I-50125 Florence, Italy;‎ LENS, Largo Enrico Fermi 2, I-50125 Florence, Italy

Abstract: We identify optimal measurement strategies for phase estimation in different scenarios in which the interferometer acts on two-mode symmetric states. For pure states of a single qubit, we show that optimal measurements form a broad set parametrized with a continuous variable. When the state is mixed, this set reduces to merely two possible measurements. For two-qubit symmetric Werner state, we find the optimal measurement and show that estimation from the population imbalance is optimal only if the state is pure. We also determine the optimal measurements for a wide class of symmetric N-qubit Werner-like states. Finally, for a pure symmetric state of N qubits, we find under which conditions the estimation from the full N-body correlation and from the population imbalance is optimal.

Giornale/Rivista: QUANTUM INFORMATION PROCESSING

Volume: 15 (5)      Da Pagina: 2231  A: 2252

Parole chiavi: Estimation theory; Quantum interferometry; Optimal measurements; Entanglement
DOI: 10.1007/s11128-016-1248-5

Citazioni: 8
dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2022-09-25
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