On Compound State and Mutual Information in Quantum Information Theory

Takashi Matsuoka, Dariusz Chruściński

Noborn Watanabe

Adaptive Dynamics and Its Applications to Chaos and NPC Problem Quantum Algorithm for SAT Problem and Quantum Mutual Entropy New Quantum Algorithm for Studying NP-Complete Problems Entanglement, Quantum Entropy and Mutual Information Fundamentals of Quantum Mutual Entropy and Capacity Compound Channels, Transition Expectations, and Liftings Complexities and Their Applications to Characterization of Chaos Complexity, Fractal Dimension for Quantum States Information Dynamics and Its Applications to Optical Communication Processes Information Theoretical Treatments of Genes Some Aspects of Quantum Information Theory and Their Applications to Irreversible Processes On Compound State and Mutual Information in Quantum Information Theory Note on Quantum Probability Quantum Ergodic Channels in Operator Algebras On Open System Dynamics -- An Operator Algebraic Study Dynamical Process in Linear Response Theory Stability of Weiss Ising Model and other papers.

Guillaume Aubrun, Stanisław Szarek

Bao Guanggui

The mutual information in quantum information systems is defined by using the quantum compound state, and its fundamental properties with an application are studied.

V. P. Belavkin, Masanori Ohya

Quantum entanglements, describing truly quantum couplings, are stu died and classified from the point of view of quantum compound states. We show that c lassical-quantum correspondences such as quantum encodings can be treated as d-entanglements leading to a special class of the separable compound states. The mutual information of the d-compound and entangled states lead to two di fferent types of entropies for a given quantum state: the von Neumann entrop y, which is achieved as the supremum of the information over all d-entanglem ents, and the dimensional entropy, which is achieved at the standard entangl ement, the true quantum entanglement, coinciding with a d-entanglement only in the commutative case. The q-capacity of a quantum noiseless channel, defi ned as the supremum over all entanglements, is given as the logarithm of the dimensionality of the input von Neumann algebra. It can double the classical capacity, achieved as the supremum over all semi-quantum couplings (d-entang lements, or encodings), which is bounded by the logarithm of the dimensional ity of a maximal Abelian subalgebra.