Measurement-driven quantum evolution

Roa L.; Delgado, A.; Ladron de Guevara, ML; Klimov, AB

Abstract

We study the problem of mapping an unknown mixed quantum state onto a known pure state without the use of unitary transformations. This is achieved with the help of sequential measurements of two noncommuting observables only. We show that the overall success probability is maximized in the case of measuring two observables whose eigenstates define mutually unbiased bases. We find that for this optimal case the success probability quickly converges to unity as the number of measurement processes increases and that it is almost independent of the initial state. In particular, we show that to guarantee a success probability close to one the number of consecutive measurements must be larger than the dimension of the Hilbert space. We connect these results to quantum copying, quantum deleting, and entanglement generation. © 2006 The American Physical Society.

Más información

Título según WOS: Measurement-driven quantum evolution
Título según SCOPUS: Measurement-driven quantum evolution
Título de la Revista: PHYSICAL REVIEW A
Volumen: 73
Número: 1
Editorial: AMER PHYSICAL SOC
Fecha de publicación: 2006
Idioma: English
URL: http://link.aps.org/doi/10.1103/PhysRevA.73.012322
DOI:

10.1103/PhysRevA.73.012322

Notas: ISI, SCOPUS