  Capacities of quantum channels are fundamental quantities in the theory of
quantum information. A desirable property is the additivity for a capacity.
However, this cannot be achieved for a few quantities that have been
established as capacity measures. Asymptotic regularization is generically
necessary making the study of capacities notoriously hard. In this work, by a
proper refinement of the physical settings of quantum communication, we prove
additive quantities for quantum channel capacities that can be employed for
quantum Shannon theorems. This refinement, only a tiny step away from the
standard settings, is consistent with the principle of quantum theory, and it
further demonstrates von Neumann entropy as the cornerstone of quantum
information.
