A quantum channel with additive minimum output entropy

Abstract

We give a direct proof of the additivity of the minimum output entropy of a particular quantum channel which breaks the multiplicativity conjecture. This yields additivity of the classical capacity of this channel, a result obtained by a different method by Matsumoto and Yura [quant-ph/0306009]. Our proof relies heavily upon certain concavity properties of the output entropy which are of independent interest.

15 pages, 2 figures

References in corpus (4)

• Accessible information and optimal strategies for real symmetrical quantum sources
• Remarks on additivity of the Holevo channel capacity and of the entanglement of formation
• On the multiplicativity conjecture for quantum channels
• Towards a geometrical interpretation of quantum information compression

Cited by in corpus (6)

• Additivity of minimal entropy output for a class of covariant channels
• Simplification of additivity conjecture in quantum information theory
• The maximal p-norm multiplicativity conjecture is false
• Voronoi Diagrams for Quantum States and Its Application to a Numerical Estimation of a Quantum Channel Capacity
• Qubit Channels Which Require Four Inputs to Achieve Capacity: Implications for Additivity Conjectures
• Analysis of the Entanglement Cost and Calculation of the Holevo Capacity