Oscillations of the purity in the repeated-measurement-based generation of quantum states

B. Militello, Kazuya Yuasa, Hiromichi Nakazato, A. Messina

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    Abstract

    Repeated observations of a quantum system interacting with another one can drive the latter toward a particular quantum state, irrespective of its initial condition, because of an effective nonunitary evolution. If the target state is a pure one, the degree of purity of the system approaches unity, even when the initial condition of the system is a mixed state. In this paper we study the behavior of the purity from the initial value to the final one, that is, unity. Depending on the parameters, after a finite number of measurements, the purity exhibits oscillations that brings about a lower purity than that of the initial state, which is a point to be taken care of in concrete applications.

    Original languageEnglish
    Article number042109
    JournalPhysical Review A - Atomic, Molecular, and Optical Physics
    Volume77
    Issue number4
    DOIs
    Publication statusPublished - 2008 Apr 16

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    ASJC Scopus subject areas

    • Atomic and Molecular Physics, and Optics
    • Physics and Astronomy(all)

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