English

Finite blocklength converse bounds for quantum channels

Quantum Physics 2016-01-01 v2

Abstract

We derive upper bounds on the rate of transmission of classical information over quantum channels by block codes with a given blocklength and error probability, for both entanglement-assisted and unassisted codes, in terms of a unifying framework of quantum hypothesis testing with restricted measurements. Our bounds do not depend on any special property of the channel (such as memorylessness) and generalise both a classical converse of Polyanskiy, Poor, and Verd\'{u} as well as a quantum converse of Renner and Wang, and have a number of desirable properties. In particular our bound on entanglement-assisted codes is a semidefinite program and for memoryless channels its large blocklength limit is the well known formula for entanglement-assisted capacity due to Bennett, Shor, Smolin and Thapliyal.

Keywords

Cite

@article{arxiv.1210.4722,
  title  = {Finite blocklength converse bounds for quantum channels},
  author = {William Matthews and Stephanie Wehner},
  journal= {arXiv preprint arXiv:1210.4722},
  year   = {2016}
}

Comments

15 pages, 4 figures (v2: improved notation; one mistake fixed; results unchanged)

R2 v1 2026-06-21T22:23:17.065Z