A Note on the Set of After-measurement States in Generalized Quantum Measurement

Abstract: The sets of after-measurement states for standard and generalized quantum measurements are compared. It is shown that for a SIC-POVM generalized measurement, the ratio of the volume of the set of after-measurement states and the volume of the simplex generated by individual outcomes quickly tends to zero with increase of the number of dimensions. The volumes used are based on the Hilbert-Schmidt norm. Some consequences on actual realizations, having finite collections of systems are discussed.