Abstract
The structure of covariant observables—normalized positive operator measures (POMs)—is studied in the case of a type I symmetry group. Such measures are completely determined by kernels which are measurable fields of positive semidefinite sesquilinear forms. We produce the minimal Kolmogorov decompositions for the kernels and determine those which correspond to the extreme covariant observables. Illustrative examples of the extremals in the case of the Abelian symmetry group are given.
Similar content being viewed by others
References
Carmeli, C., Heinosaari, T., Pellonpää, J.-P., Toigo, A.: Extremal covariant positive operator valued measures: The case of a compact symmetry group. J. Math. Phys. 49, 063504 (2008)
Cattaneo, U.: On Mackey’s imprimitivity theorem. Comment. Math. Helv. 54, 629–641 (1979)
Chiribella, G., D’Ariano, G.M.: Extremal covariant positive operator valued measures. J. Math. Phys. 45, 4435–4447 (2004)
D’Ariano, G.M.: Extremal covariant quantum operations and positive operator valued measures. J. Math. Phys. 45, 3620–3635 (2004)
Dixmier, J.: C *-Algebras. North-Holland, Amsterdam (1977)
Holevo, A.S.: Probabilistic and Statistical Aspects of Quantum Theory. North-Holland, Amsterdam (1982)
Holevo, A.S.: Generalized imprimitivity systems for Abelian groups. Sov. Math. (Iz. VUZ) 27, 53–80 (1983)
Holevo, A.S.: Covariant measurements and imprimitivity systems. In: Lecture Notes in Mathematics, vol. 1055, pp. 153–172 (1984)
Holevo, A.S.: On a generalization of canonical quantization. Math. USSR Izv. 28, 175–188 (1987)
Kiukas, J., Pellonpää, J.-P.: A note on infinite extreme correlation matrices. Linear Algebra Appl. 428, 2501–2508 (2008)
Li, C.-K., Tam, B.-S.: A note on extreme correlation matrices. SIAM J. Matrix Anal. Appl. 15, 903–908 (1994)
Author information
Authors and Affiliations
Corresponding author
Additional information
Dedicated to Pekka J. Lahti in honor of his sixtieth birthday
Rights and permissions
About this article
Cite this article
Holevo, A.S., Pellonpää, JP. Extreme Covariant Observables for Type I Symmetry Groups. Found Phys 39, 625–641 (2009). https://doi.org/10.1007/s10701-009-9274-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10701-009-9274-0