In this paper the relation between quantum covariances and quantum Fisher informations are studied. This study is applied to generalize a recently proved uncertainty relation based on quantum Fisher information. The proof given hereconsiderably simplifies the previously proposed proofs and leads to more general inequalities.
For a quantum state and a set of observables, we can construct an associated covariance matrix and a natural quantum Fisher information matrix. These two matrices characterize the uncertainty and information content of the observables in the relevant state. An inequality between these two matrices is established. This inequality may be interpreted as a general quantification of the Heisenberg uncertainty principle from a statistical estimation perspective. In particular, it implies a new uncertainty relation which refines the celebrated Schrödinger uncertainty relation.
Heisenberg and Schr{\"o}dinger uncertainty principles give lower bounds for the product of variances Varρ(A)⋅Varρ(B), in a state ρ, if the observables A,B are not compatible, namely if the commutator [A,B] is not zero. In this paper we prove an uncertainty principle in Schr{\"o}dinger form where the bound for the product of variances Varρ(A)⋅Varρ(B) depends on the area spanned by the commutators [ρ,A] and [ρ,B] with respect to an arbitrary quantum version of the Fisher information.