Accessible information in three pure mirror-symmetric qubit states
Michael R. Frey · Physical Review A · 2006
We formulate an expression for the accessible information in mirror-symmetric ensembles of real qubit states. This expression is used to make a detailed study of optimum quantum measurements for extracting the accessible information in three-state, mirror-symmetric ensembles. Distinct measurement regimes are identified for these ensembles with optimal measurement strategies involving different numbers of measurement operators, similar to results found for minimum error discrimination. Our results generalize known results for the accessible information in two pure states and in the trine ensemble.