Complete Characterization of Pure Quantum Measurements and Quantum Channels
arXiv:1007.3211 · doi:10.1088/1751-8113/44/8/085304
Abstract
We give a complete characterization for pure quantum measurements, i.e., for POVMs which are extremals in the convex set of all POVMs. Such measurements are free from classical noise. The characterization is valid both in discrete and continuous cases, and also in the case of an infinite Hilbert space. We show that sharp measurements are clean, i.e. they cannot be irreversibly connected to another POVMs via quantum channels and thus they are free from any additional quantum noise. We exhibit an example which demonstrates that this result could also be approximately true for pure measurements.
5 pages
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- Notes on Deterministic Programming of Quantum Observables and Channels
- Approximately Clean Quantum Probability Measures
- Reduction and extremality of finite observables
- Entropic partial orderings of quantum measurements
- Compressing continuous variable quantum measurements
- Barycentric decomposition for quantum instruments