English

On complementary channels and the additivity problem

Quantum Physics 2007-07-05 v3

Abstract

We explore complementarity between output and environment of a quantum channel (or, more generally, CP map), making an observation that the output purity characteristics for complementary CP maps coincide. Hence, validity of the mutiplicativity/additivity conjecture for a class of CP maps implies its validity for complementary maps. The class of CP maps complementary to entanglement-breaking ones is described and is shown to contain diagonal CP maps as a proper subclass, resulting in new class of CP maps (channels) for which the multiplicativity/additivity holds. Covariant and Gaussian channels are discussed briefly in this context.

Keywords

Cite

@article{arxiv.quant-ph/0509101,
  title  = {On complementary channels and the additivity problem},
  author = {A. S. Holevo},
  journal= {arXiv preprint arXiv:quant-ph/0509101},
  year   = {2007}
}

Comments

11 pages; references added, typos corrected