Activation and superactivation of single-mode Gaussian quantum channels
Name
PhysRevA.99.032337.pdf
Size
636.77 KB
Format
Adobe PDF
Checksum (MD5)
9d858b42fe723c2602596399de7f79f5
Author(s)
Lim, Youngrong
Takagi, Ryuji
Adesso, Gerardo
Lee, Soojoon
Date Issued
March 2019
Journal
Physical Review A
Publisher
American Physical Society
Citation
Lim, Youngrong et al. "Activation and superactivation of single-mode Gaussian quantum channels." Physical Review A 99, 3 (March 2019): 032337 © 2019 American Physical Society
Version
Final published version
Abstract
Activation of quantum capacity is a surprising phenomenon according to which the quantum capacity of a certain channel may increase by combining it with another channel with zero quantum capacity. Superactivation describes an even more particular occurrence, in which both channels have zero quantum capacity, but their composition has a nonvanishing one. We investigate these effects for all single-mode phase-insensitive Gaussian channels, which include thermal attenuators and amplifiers, assisted by a two-mode positive-partial-transpose channel. Our result shows that activation phenomena are special but not uncommon. We can reveal superactivation in a broad range of thermal attenuator channels, even when the transmissivity is quite low, or the thermal noise is high. This means that we can transmit quantum information reliably through very noisy Gaussian channels with the help of another Gaussian channel, whose quantum capacity is also zero. We further show that no superactivation is possible for entanglement-breaking Gaussian channels in physically relevant circumstances by proving the nonactivation property of the coherent information of bosonic entanglement-breaking channels with finite input energy.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PhysRevA.99.032337
