Broadcasting quantum fisher information

Abstract

It is well known that classical information can be cloned, but nonorthogonal quantum states cannot be cloned, and noncommuting quantum states cannot be broadcast. We conceive a scenario in which the object we want to broadcast is the statistical distinguishability, as quantified by quantum Fisher information, about a signal parameter encoded in quantum states. We show that quantum Fisher information cannot be cloned, while it might be broadcast even when the input states are noncommuting. This situation interpolates between cloning of classical information and no broadcasting of quantum information, and indicates a hybrid way of information broadcasting which is of particular significance from both practical and theoretical perspectives. © 2013 American Physical Society.