Metrics on the set of states of a W∗-algebra

Abstract For any q ϵ [1, + ∞) a metric d q is defined on the set of states of a W ∗ -algebra. It is shown that d 1 is the Jauch-Misra-Gibson metric, whereas d 2 is the Bures-Cantoni metric. All these metrics are uniformly equivalent. Limit properties and alternative expressions are given.