No abstract

No abstract

We investigate the problem of comparing quantum statistical models in the general operator algebra framework in arbitrary dimension, thus generalizing results obtained so far in finite dimension, and for the full algebra of operators on a Hilbert space. In particular, the quantum Blackwell–Sherman–Stein theorem is obtained, and informational subordination of quantum information structures is characterized.

Cloneable sets of states in C*-algebras are characterized in terms of strong orthogonality of states. Moreover, the relation between strong cloning and distinguishability of states is investigated together with some additional properties of strong cloning in abelian C*-algebras.

ABSTRACT. Some aspects of weak sufficiency of quantum statistics are investigated. In particular, we give necessary and sufficient conditions for the existence of a weakly sufficient statistic for a given family of vector states, investigate the problem of its minimality, and find the relation between weak sufficiency and other notions of sufficiency employed so far.