2004/12/31 by M. M. Wolf, M M Wolf, J. Eisert +1 · 3 citations
Computer Science · Engineering · Physics and Astronomy · #Quantum Information and Cryptography #Quantum many-body systems #Wireless Communication Security Techniques #quant-ph
paper · pdf · doi:10.1088/1367-2630/7/1/093
published as New J. Phys. 7, 93 (2005) · 14 pages, RevTeX (replaced with published version)
openalex publication_date 2005/04/12 · arxiv created 2005/04/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We consider the additivity of the minimal output entropy and the classical information capacity of a class of quantum channels. For this class of channels, the norm of the output is maximized for the output being a normalized projection. We prove the additivity of the minimal output Renyi entropies with entropic parameters α ∊ [0, 2], generalizing an argument by Alicki and Fannes, and present a number of examples in detail. In order to relate these results to the classical information capacity, we introduce a weak form of covariance of a channel. We then identify various instances of weakly covariant channels for which we can infer the additivity of the classical information capacity. Both additivity results apply to the case of an arbitrary number of different channels. Finally, we relate the obtained results to instances of bi-partite quantum states for which the entanglement cost can be calculated.