Abstract
Let be the von Neumann entropy of a finite ensemble of pure quantum states. We show that may be naturally viewed as a function of a set of geometrical volumes in Hilbert space defined by the states and that is monotonically increasing in each of these variables. Since is the Schumacher compression limit of , this monotonicity property suggests a geometrical interpretation of the quantum redundancy involved in the compression process. It provides clarification of previous work in which it was shown that may be increased while increasing the overlap of each pair of states in the ensemble. As a by-product, our mathematical techniques also provide an interpretation of the subentropy of .
- Received 30 October 2003
DOI:https://doi.org/10.1103/PhysRevA.69.032304
©2004 American Physical Society