Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published June 10, 2011 | Supplemental Material + Published
Journal Article Open

Entangled Inputs Cannot Make Imperfect Quantum Channels Perfect

Abstract

Entangled inputs can enhance the capacity of quantum channels, this being one of the consequences of the celebrated result showing the nonadditivity of several quantities relevant for quantum information science. In this work, we answer the converse question (whether entangled inputs can ever render noisy quantum channels to have maximum capacity) to the negative: No sophisticated entangled input of any quantum channel can ever enhance the capacity to the maximum possible value, a result that holds true for all channels both for the classical as well as the quantum capacity. This result can hence be seen as a bound as to how "nonadditive quantum information can be." As a main result, we find first practical and remarkably simple computable single-shot bounds to capacities, related to entanglement measures. As examples, we discuss the qubit amplitude damping and identify the first meaningful bound for its classical capacity.

Additional Information

© 2011 American Physical Society. (Received 26 November 2010; published 10 June 2011) We thank M. Christandl, A. Harrow, M. P. Müller, and A. Winter for useful feedback. F. G. S. L. B. is supported by the Brazilian agency Fundação de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG). J. E. is supported by the EU (QESSENCE, MINOS, COMPAS), the BMBF (QuOReP), and the EURYI. M. H. is supported by MNiSW Grant No. N202 231937 and by the EU (QESSENCE). D. Y. is supported by NSFC (Grant No. 10805043). Part of this work was done in KCIK. F. G. S. L. B., J. E., and M. H. are thankful for the hospitality of the Mittag-Leffler institute, where part of this work has been done.

Attached Files

Published - PhysRevLett.106.230502.pdf

Supplemental Material - EPAPS.pdf

Supplemental Material - EPAPS.tex

Files

PhysRevLett.106.230502.pdf
Files (185.2 kB)
Name Size Download all
md5:af14092b345bc54687f9970bcec0383b
154.6 kB Preview Download
md5:332a5bc4d96be867a9f5f375de3913fd
4.6 kB Download
md5:043b0ab417d9df7b002c7cbe94a6d39f
26.0 kB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023