The quantum Fisher information is a Riemannian metric, defined on the state
space of a quantum system, which is symmetric and decreasing under stochastic
mappings. Contrary to the classical case such a metric is not unique. We
complete the characterization, initiated by Morozova, Chentsov and Petz, of
these metrics by providing a closed and tractable formula for the set of
Morozova-Chentsov functions. In addition, we provide a continuously increasing
bridge between the smallest and largest symmetric monotone metrics.Comment: Minor revision with new title and abstract as suggested by a refere
