Optimal scheme for estimating a pure qubit state via local measurements
Bagán Capella, Emili (Universitat Autònoma de Barcelona. Departament de Física)
Baig i Aleu, Marià, 1955- (Universitat Autònoma de Barcelona. Departament de Física)
Muñoz Tapia, Ramon (Universitat Autònoma de Barcelona. Departament de Física)
American Physical Society

Date:	2002
Abstract:	We present the optimal scheme for estimating a pure qubit state by means of local measurements on N identical copies. We give explicit examples for low N. For large N, we show that the fidelity saturates the collective measurement bound up to order 1/N. When the signal state lays on a meridian of the Bloch sphere, we show that this can be achieved without classical communication.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; Versió publicada
Published in:	Physical review letters, Vol. 89, Issue 27 (December 2002) , p. 277904, ISSN 1079-7114

DOI: 10.1103/PhysRevLett.89.277904

4 p, 101.5 KB

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