Data di Pubblicazione:
2014
Citazione:
Probing qubit by qubit : properties of the POVM and the information/ disturbance tradeoff / C. Sparaciari, M.G.A. Paris. - In: INTERNATIONAL JOURNAL OF QUANTUM INFORMATION. - ISSN 0219-7499. - 12:2(2014), pp. 1461012.1-1461012.10. [10.1142/S0219749914610127]
Abstract:
We address the class of positive operator-valued measures (POVMs) for qubit systems that are obtained by coupling the signal qubit with a probe qubit and then performing a projective measurement on the sole probe system. These POVMs, which represent the simplest class of qubit POVMs, depends on 3 + 3 + 2 = 8 free parameters describing the initial preparation of the probe qubit, the Cartan representative of the unitary coupling, and the projective measurement at the output, respectively. We analyze in some detail the properties of the POVM matrix elements, and investigate their values for given ranges of the free parameters. We also analyze in detail the tradeoff between information and disturbance for different ranges of the free parameters, showing, among other things, that (i) typical values of the tradeoff are close to optimality and (ii) even using a maximally mixed probe one may achieve optimal tradeoff.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
information/disturbance tradeoff; Naimark theorem; Quantum measurements
Elenco autori:
C. Sparaciari, M.G.A. Paris
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