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We consider the Gaussian channel with power constraint P. A gap exists between the channel capacity and the highest achievable rate of equiprobable uniformly spaced signal. Several approaches enable to overcome this limitation such as…

Information Theory · Computer Science 2015-03-17 Hugo Meric

The capacity of accelerated channel is investigated for different classes of initial states. It is shown that, the capacities of the travelling channels depend on the frame in which the accelerated channels are observed in and the initial…

Quantum Physics · Physics 2014-02-04 N. Metwally , A. Sagheer

In this work, novel upper and lower bounds for the capacity of channels with arbitrary constraints on the support of the channel input symbols are derived. As an immediate practical application, the case of multiple-input multiple-output…

Information Theory · Computer Science 2017-09-01 Alex Dytso , Mario Goldenbaum , Shlomo Shamai , H. Vincent Poor

We consider the use of the well-known dual capacity bounding technique for deriving upper bounds on the capacity of indecomposable finite-state channels (FSCs) with finite input and output alphabets. In this technique, capacity upper bounds…

Information Theory · Computer Science 2021-07-13 Bashar Huleihel , Oron Sabag , Haim H. Permuter , Navin Kashyap , Shlomo Shamai

Degradable quantum channels are among the only channels whose quantum and private classical capacities are known. As such, determining the structure of these channels is a pressing open question in quantum information theory. We give a…

Quantum Physics · Physics 2009-11-13 Toby S. Cubitt , Mary-Beth Ruskai , Graeme Smith

The capacity of classical channels is convex. This is not the case for the quantum capacity of a channel: the capacity of a mixture of different quantum channels exceeds the mixture of the individual capacities and thus is non-convex. Here…

Quantum Physics · Physics 2016-10-26 David Elkouss , Sergii Strelchuk

Quantum channel capacity is a fundamental quantity in order to understand how good can quantum information be transmitted or corrected when subjected to noise. However, it is generally not known how to compute such quantities, since the…

Quantum Physics · Physics 2023-09-20 Josu Etxezarreta Martinez , Antonio deMarti iOlius , Pedro M. Crespo

A recent method to certify the classical capacity of quantum communication channels is applied for general damping channels in finite dimension. The method compares the mutual information obtained by coding on the computational and a…

Quantum Physics · Physics 2020-10-23 Chiara Macchiavello , Massimiliano F. Sacchi , Tito Sacchi

We investigate the Weyl channels being covariant with respect to the maximum commutative group of unitary operators. This class includes the quantum depolarizing channel and the "two-Pauli" channel as well. Then, we show that our estimation…

Quantum Physics · Physics 2009-11-13 G. G. Amosov

Entangled inputs can enhance the capacity of quantum channels, this being one of the consequences of the celebrated result showing the non-additivity of several quantities relevant for quantum information science. In this work, we answer…

Quantum Physics · Physics 2015-05-20 Fernando G. S. L. Brandao , Jens Eisert , Michal Horodecki , Dong Yang

We consider quantum channels with one sender and two receivers, used in several different ways for the simultaneous transmission of independent messages. We begin by extending the technique of superposition coding to quantum channels with a…

Quantum Physics · Physics 2011-10-25 Jon Yard , Patrick Hayden , Igor Devetak

We introduce various measures of forward classical communication for bipartite quantum channels. Since a point-to-point channel is a special case of a bipartite channel, the measures reduce to measures of classical communication for…

Quantum Physics · Physics 2023-04-25 Dawei Ding , Sumeet Khatri , Yihui Quek , Peter W. Shor , Xin Wang , Mark M. Wilde

This article provides an elementary introduction to Gaussian channels and their capacities. We review results on the classical, quantum, and entanglement assisted capacities and discuss related entropic quantities as well as additivity…

Quantum Physics · Physics 2009-05-15 J. Eisert , M. M. Wolf

We define and study the properties of channels which are analogous to unital qubit channels in several ways. A full treatment can be given only when the dimension d is a prime power, in which case each of the (d+1) mutually unbiased bases…

Quantum Physics · Physics 2009-11-13 M. Nathanson , M. B. Ruskai

The ability to distribute entanglement over complex quantum networks is an important step towards a quantum internet. Recently, there has been significant theoretical effort, mainly focusing on the distribution of bipartite entanglement via…

Quantum Physics · Physics 2017-05-19 Stefan Bäuml , Koji Azuma

We calculate and analyze the bounds of the Holevo capacity and classical capacity for the generalized Pauli channels. In particular, we obtain the lower and upper bounds of the Holevo capacity and show that if these bounds coincide, the…

Quantum Physics · Physics 2020-10-28 Katarzyna Siudzińska

We review recent results on the simulation of quantum channels, the reduction of adaptive protocols (teleportation stretching), and the derivation of converse bounds for quantum and private communication, as established in PLOB [Pirandola,…

We introduce Partially Coherent Direct Sum (PCDS) quantum channels, as a generalization of the already known Direct Sum quantum channels. We derive necessary and sufficient conditions to identify the subset of those maps which are…

Quantum Physics · Physics 2021-07-21 Stefano Chessa , Vittorio Giovannetti

Entanglement shared between the two ends of a quantum communication channel has been shown to be a useful resource in increasing both the quantum and classical capacities for these channels. The entanglement-assisted capacities were derived…

Quantum Physics · Physics 2009-11-07 Garry Bowen

In this paper we fill the gap in previous works by proving the formula for entanglement-assisted capacity of quantum channel with additive constraint (such as bosonic Gaussian channel). The main tools are the coding theorem for…

Quantum Physics · Physics 2009-11-07 A. S. Holevo