Activation and superactivation of single-mode Gaussian quantum channels

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...

Full description

Bibliographic Details
Main Authors: Lim, Youngrong (Author), Takagi, Ryuji (Author), Adesso, Gerardo (Author), Lee, Soojoon (Author)
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor)
Format: Article
Language:English
Published: American Physical Society, 2019-06-17T17:26:52Z.
Subjects:
Online Access:Get fulltext
LEADER 01943 am a22002053u 4500
001 121324
042 |a dc 
100 1 0 |a Lim, Youngrong  |e author 
100 1 0 |a Massachusetts Institute of Technology. Center for Theoretical Physics  |e contributor 
100 1 0 |a Massachusetts Institute of Technology. Department of Physics  |e contributor 
700 1 0 |a Takagi, Ryuji  |e author 
700 1 0 |a Adesso, Gerardo  |e author 
700 1 0 |a Lee, Soojoon  |e author 
245 0 0 |a Activation and superactivation of single-mode Gaussian quantum channels 
260 |b American Physical Society,   |c 2019-06-17T17:26:52Z. 
856 |z Get fulltext  |u https://hdl.handle.net/1721.1/121324 
520 |a 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. 
546 |a en 
655 7 |a Article 
773 |t Physical Review A