scholarly journals Superadditivity of the Classical Capacity with Limited Entanglement Assistance

2017 ◽  
Vol 119 (4) ◽  
Author(s):  
Elton Yechao Zhu ◽  
Quntao Zhuang ◽  
Peter W. Shor
Keyword(s):  
Classical Capacity

scholarly journals On the Classical Capacity of General Quantum Gaussian Measurement

Entropy ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 377
Author(s):  
Alexander Holevo
Keyword(s):  
Dual Problem ◽  
Measurement Channel ◽  
Gaussian Channel ◽  
Quantum Communications ◽  
Classical Capacity ◽  
Optimal Ensemble ◽  
Accessible Information ◽  
Measurement Channels ◽  
Gaussian Ensemble ◽  
Average State

In this paper, we consider the classical capacity problem for Gaussian measurement channels. We establish Gaussianity of the average state of the optimal ensemble in the general case and discuss the Hypothesis of Gaussian Maximizers concerning the structure of the ensemble. Then, we consider the case of one mode in detail, including the dual problem of accessible information of a Gaussian ensemble. Our findings are relevant to practical situations in quantum communications where the receiver is Gaussian (say, a general-dyne detection) and concatenation of the Gaussian channel and the receiver can be considered as one Gaussian measurement channel. Our efforts in this and preceding papers are then aimed at establishing full Gaussianity of the optimal ensemble (usually taken as an assumption) in such schemes.

Teleportation and dense coding via a multiparticle quantum channel of the GHZ-class

2002 ◽  
Vol 2 (5) ◽  
pp. 367-378
Author(s):  
V.N. Gorbachev ◽  
A.I. Zhiliba ◽  
A.I. Trubilko ◽  
A.A. Rodichkina
Keyword(s):  
Quantum Channel ◽  
Entangled States ◽  
Dense Coding ◽  
Ghz States ◽  
Classical Capacity ◽  
Coding Schemes ◽  
One To One

A set of protocols for teleportation and dense coding schemes based on a multiparticle quantum channel, represented by the $N$-particle entangled states of the GHZ class, is introduced. Using a found representation for the GHZ states, it was shown that for dense coding schemes enhancement of the classical capacity of the channel due from entanglement is $N/N-1$. Within the context of our schemes it becomes clear that there is no one-to one correspondence between teleportation and dense coding schemes in comparison when the EPR channel is exploited. A set of schemes, for which two additional operations as entanglement and disentanglement are permitted, is considered.

scholarly journals Quantum and classical capacity boosted by a Lorentz transformation

2014 ◽  
Vol 90 (2) ◽  
Author(s):  
Kamil Brádler ◽  
Esteban Castro-Ruiz ◽  
Eduardo Nahmad-Achar
Keyword(s):  
Lorentz Transformation ◽  
Classical Capacity
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