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We give the trade-off curve showing the capacity of a quantum channel as a function of the amount of entanglement used by the sender and receiver for transmitting information. The endpoints of this curve are given by the…

Quantum Physics · Physics 2007-05-23 Peter W. Shor

For any quantum discrete memoryless channel, we define a quantity called quantum entanglement capacity with classical feedback ($E_B$), and we show that this quantity lies between two other well-studied quantities. These two quantities -…

Quantum Physics · Physics 2009-11-13 Alan W. Leung

Quantum information theory is the study of the achievable limits of information processing within quantum mechanics. Many different types of information can be accommodated within quantum mechanics, including classical information, coherent…

Quantum Physics · Physics 2007-05-23 M. A. Nielsen

We examine the behavior of quantum correlations of spin pairs in a finite anisotropic $XY$ spin chain immersed in a transverse magnetic field, through the analysis of the quantum discord and the conventional and quadratic one…

Quantum Physics · Physics 2015-05-20 N. Canosa , L. Ciliberti , R. Rossignoli

Current advancements in communication equipment demand the investigation of classical information transfer over quantum channels, by encompassing realistic scenarios in finite dimensions. To address this issue, we develop a framework for…

Quantum Physics · Physics 2026-01-08 Sudipta Mondal , Pritam Halder , Saptarshi Roy , Aditi Sen De

The set of Multi-level Amplitude Damping (MAD) quantum channels is introduced as a generalization of the standard qubit Amplitude Damping Channel to quantum systems of finite dimension $d$. In the special case of $d=3$, by exploiting…

Quantum Physics · Physics 2021-03-03 Stefano Chessa , Vittorio Giovannetti

A direct proof of the relation between the one-shot classical capacity and the minimal output entropy for covariant quantum channels is suggested. The structure of covariant channels is described in some detail. A simple proof of a general…

Quantum Physics · Physics 2007-05-23 A. S. Holevo

In this study, we explore the information capacity of open quantum systems, focusing on the effective channels formed by the subsystem of random quantum circuits and quantum Hamiltonian evolution. By analyzing the subsystem information…

Quantum Physics · Physics 2025-06-26 Yu-Qin Chen , Shuo Liu , Shi-Xin Zhang

Using the Lieb-Robinson inequality and the continuity property of the quantum capacities in terms of the diamond norm, we derive an upper bound on the values that these capacities can attain in spin-network communication i.i.d. models of…

Quantum Physics · Physics 2019-10-01 Stefano Chessa , Marco Fanizza , Vittorio Giovannetti

We exhibit discrete memoryless quantum channels whose quantum capacity assisted by two-way classical communication, $Q_2$, exceeds their unassisted one-shot Holevo capacity $C_H$. These channels may be thought of as having a data input and…

Quantum Physics · Physics 2007-05-23 Charles H. Bennett , Igor Devetak , Peter W. Shor , John A. Smolin

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

Transmitting data reliably over noisy communication channels is one of the most important applications of information theory, and well understood when the channel is accurately modelled by classical physics. However, when quantum effects…

A quantum communication channel can be put to many uses: it can transmit classical information, private classical information, or quantum information. It can be used alone, with shared entanglement, or together with other channels. For each…

Information Theory · Computer Science 2010-07-20 Graeme Smith

A chain of interacting spin behaves like a quantum mediator (quantum link) which allows two distant parties that control the ends of the chain to exchange quantum messages. We show that over repeated uses without resetting the study of a…

Quantum Physics · Physics 2009-11-13 Vittorio Giovannetti , Daniel Burgarth , Stefano Mancini

Effective information transmission is a central element in quantum information protocols, but the quest for optimal efficiency in channels with symmetrical characteristics remains a prominent challenge in quantum information science. In…

Quantum Physics · Physics 2023-11-02 Atta ur Rahman , S. M. Zangi , Ma-Cheng Yang , Cong-Feng Qiao

Many quantum information theoretic quantities are similar to and/or inspired by thermodynamic quantities, with entanglement entropy being a well-known example. In this paper, we study a less well-known example, capacity of entanglement,…

High Energy Physics - Theory · Physics 2019-04-03 Jan de Boer , Jarkko Järvelä , Esko Keski-Vakkuri

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

Quantum correlations in an entangled many-body system are capable of storing information. Even when the information is injected by a local unitary operation to the system, the entanglement delocalizes it. In a recent study on multiple-qubit…

Quantum Physics · Physics 2020-06-04 Koji Yamaguchi , Masahiro Hotta

A formula for the capacity of a quantum channel for transmitting private classical information is derived. This is shown to be equal to the capacity of the channel for generating a secret key, and neither capacity is enhanced by forward…

Quantum Physics · Physics 2007-05-23 I. Devetak

The study of mutual entropy (information) and capacity in classica l system was extensively done after Shannon by several authors like Kolmogor ov and Gelfand. In quantum systems, there have been several definitions of t he mutual entropy…

Quantum Physics · Physics 2007-05-23 Masanori Ohya