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Quantum communication relies on the existence of high quality quantum channels to exchange information. In practice, however, all communication links are affected by noise from the environment. Here we investigate the ability of quantum…

Quantum Physics · Physics 2025-08-12 Vishal Singh , Mark M. Wilde

We consider a variation of the multi-party communication complexity scenario where the parties are supplied with an extra resource: particles in an entangled quantum state. We show that, although a prior quantum entanglement cannot be used…

Quantum Physics · Physics 2007-05-23 Harry Buhrman , Richard Cleve , Wim van Dam

It is shown that the capacity of a classical-quantum channel with arbitrary (possibly mixed) states equals to the maximum of the entropy bound with respect to all apriori distributions. This completes the recent result of Hausladen, Jozsa,…

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

We analyze the quantum binary adder channel, i.e. the quantum generalization of the classical, and well-studied, binary adder channel: in this model qubits rather than classical bits are transmitted. This of course is as special case of the…

Quantum Physics · Physics 2007-05-23 Gleb V. Klimovitch , Andreas Winter

It is easy to show coincidence of the entanglement-assisted classical capacity and the Holevo capacity for any c-q channel between finite dimensional quantum systems. In this paper we prove the converse assertion: coincidence of the…

Quantum Physics · Physics 2012-07-24 M. E. Shirokov

In this article we consider flagged extensions of convex combination of quantum channels, and find general sufficient conditions for the degradability of the flagged extension. An immediate application is a bound on the quantum $Q$ and…

Quantum Physics · Physics 2022-02-09 Farzad Kianvash , Marco Fanizza , Vittorio Giovannetti

In quantum Shannon theory, the way information is encoded and decoded takes advantage of the laws of quantum mechanics, while the way communication channels are interlinked is assumed to be classical. In this Letter we relax the assumption…

Quantum Physics · Physics 2018-03-28 Daniel Ebler , Sina Salek , Giulio Chiribella

Quantum mechanics allows for situations where the relative order between two processes is entangled with a quantum degree of freedom. Here we show that such entanglement can enhance the ability to transmit quantum information over noisy…

Quantum Physics · Physics 2018-09-20 Sina Salek , Daniel Ebler , Giulio Chiribella

Quantum networks are composed of quantum nodes that interact coherently by way of quantum channels and open a broad frontier of scientific opportunities. For example, a quantum network can serve as a `web' for connecting quantum processors…

Quantum Physics · Physics 2011-10-31 K. S. Choi , A. Goban , S. B. Papp , S. J. van Enk , H. J. Kimble

In this paper we address the issue of universal or robust communication over quantum channels. Specifically, we consider memoryless communication scenario with channel uncertainty which is an analog of compound channel in classical…

Quantum Physics · Physics 2009-11-13 I. Bjelakovic , H. Boche , J. Noetzel

Quantum hypothesis testing has been greatly advanced for the binary discrimination of two states, or two channels. In this setting, we already know that quantum entanglement can be used to enhance the discrimination of two bosonic channels.…

Quantum Physics · Physics 2020-07-30 Quntao Zhuang , Stefano Pirandola

We explore several new converse bounds for classical communication over quantum channels in both the one-shot and asymptotic regimes. First, we show that the Matthews-Wehner meta-converse bound for entanglement-assisted classical…

Quantum Physics · Physics 2019-08-07 Xin Wang , Kun Fang , Marco Tomamichel

Quantum resources enable us to achieve an exponential advantage in learning the properties of unknown physical systems by employing quantum memory. While entanglement with quantum memory is recognized as a necessary qualitative resource,…

Quantum Physics · Physics 2026-02-26 Minsoo Kim , Changhun Oh

We give a capacity formula for the classical information transmission over a noisy quantum channel, with separable encoding by the sender and limited resources provided by the receiver's pre-shared ancilla. Instead of a pure state, we…

Quantum Physics · Physics 2017-05-22 Quntao Zhuang , Elton Yechao Zhu , Peter W. Shor

Two-qubit operations may be characterized by their capacities for communication, both with and without free entanglement, and their capacity for creating entanglement. We establish a set of inequalities that give an ordering to the…

Quantum Physics · Physics 2007-05-23 Dominic W. Berry , Barry C. Sanders

We address the problem of discriminating with minimal error probability two given quantum operations. We show that the use of entangled input states generally improves the discrimination. For Pauli channels we provide a complete comparison…

Quantum Physics · Physics 2009-11-11 Massimiliano F. Sacchi

The capacity of a channel is known to be equivalent to the highest rate at which it can generate entanglement. Analogous to entanglement, the notion of a causality measure characterises the temporal aspect of quantum correlations. Despite…

Quantum Physics · Physics 2020-02-24 Robert Pisarczyk , Zhikuan Zhao , Yingkai Ouyang , Vlatko Vedral , Joseph F. Fitzsimons

We present an upper bound for the quantum channel capacity that is both additive and convex. Our bound can be interpreted as the capacity of a channel for high-fidelity quantum communication when assisted by a family of channels that have…

Quantum Physics · Physics 2008-08-28 Graeme Smith , John A. Smolin , Andreas Winter

We derive the general formula for the capacity of a noiseless quantum channel assisted by an arbitrary amount of noisy entanglement. In this capacity formula, the ratio of the quantum mutual information and the von Neumann entropy of the…

Quantum Physics · Physics 2007-05-23 Michal Horodecki , Pawel Horodecki , Ryszard Horodecki , Debbie Leung , Barbara Terhal

Quantum communication theory focuses on the study of quantum channels for transmitting quantum information, where the transmission rate is measured by quantum channel capacity. This quantity exhibits several intriguing properties, such as…

Quantum Physics · Physics 2025-01-14 Changchun Zhong