Some measurements in quantum mechanics disturb each other. This has puzzled physicists
since the formulation of the theory, but only in recent decades has the incompatibility of …

Compatibility conditions of quantum channels featuring symmetry through covariance are
studied. Compatibility here means the possibility of obtaining two or more channels through …

A generalization of the Choi–Jamiołkowski isomorphism for completely positive maps
between operator algebras is introduced. Particular emphasis is placed on the case of …

We discuss symmetric quantum measurements and the associated covariant observables
modelled, respectively, as instruments and positive-operator-valued measures. The …

Using probability operators and Fourier transforms of CP-instruments on von Neumann
algebras, we give necessary and sufficient conditions for operators to be probability …

We study positive kernels on X× X, where X is a set equipped with an action of a group, and
taking values in the set of A-sesquilinear forms on a (not necessarily Hilbert) module over a …