On classical capacity of Weyl channels

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.

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Superadditivity of the Classical Capacity with Limited Entanglement Assistance

Physical Review Letters ◽

10.1103/physrevlett.119.040503 ◽

2017 ◽

Vol 119 (4) ◽

Cited By ~ 5

Author(s):

Elton Yechao Zhu ◽

Quntao Zhuang ◽

Peter W. Shor

Keyword(s):

Classical Capacity

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Entanglement-enhanced classical capacity of quantum communication channels with memory in arbitrary dimensions

Physical Review A ◽

10.1103/physreva.74.032320 ◽

2006 ◽

Vol 74 (3) ◽

Cited By ~ 29

Author(s):

E. Karpov ◽

D. Daems ◽

N. J. Cerf

Keyword(s):

Quantum Communication ◽

Communication Channels ◽

Classical Capacity ◽

Arbitrary Dimensions ◽

With Memory

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

Quantum Information and Computation ◽

10.26421/qic2.5-4 ◽

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.

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