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In this article, we investigate the additivity phenomenon in the dynamic capacity of a quantum channel for trading classical communication, quantum communication and entanglement. Understanding such additivity property is important if we…

Quantum Physics · Physics 2017-08-17 Elton Yechao Zhu , Quntao Zhuang , Min-Hsiu Hsieh , Peter W. Shor

Thermal attenuator channels model the decoherence of quantum systems interacting with a thermal bath, e.g., a two-level system subject to thermal noise and an electromagnetic signal travelling through a fiber or in free-space. Hence…

Quantum Physics · Physics 2018-12-12 Matteo Rosati , Andrea Mari , Vittorio Giovannetti

We investigate super dense coding in the presence of noise, i.e. the subsystems of the entangled resource state have to pass a noisy unital quantum channel between the sender and the receiver. We discuss explicitly the case of Pauli…

Quantum Physics · Physics 2015-05-18 Zahra Shadman , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruss

Quantum information theory predicts that when the transmission resource is doubled in quantum channels, the amount of information transmitted can be increased more than twice by quantum channel coding technique, whereas the increase is at…

Quantum Physics · Physics 2009-11-10 M. Takeoka , M. Fujiwara , J. Mizuno , M. Sasaki

Finding the optimal encoding strategies can be challenging for communication using quantum channels, as classical and quantum capacities may be superadditive. Entanglement assistance can often simplify this task, as the…

Quantum Physics · Physics 2017-08-01 Elton Yechao Zhu , Quntao Zhuang , Peter W. Shor

We investigate practical finite-blocklength classical-quantum channel coding over the quantum amplitude damping channel (ADC), aiming to transmit classical information reliably through quantum outputs. Our findings indicate that for any…

Information Theory · Computer Science 2025-09-19 Tamás Havas , Hsuan-Yin Lin , Eirik Rosnes , Ching-Yi Lai

We derive universal classical-quantum superposition coding and universal classical-quantum multiple access channel code by using generalized packing lemmas for the type method. Using our classical-quantum universal superposition code, we…

Quantum Physics · Physics 2022-04-26 Masahito Hayashi , Ning Cai

A fully general strong converse for channel coding states that when the rate of sending classical information exceeds the capacity of a quantum channel, the probability of correctly decoding goes to zero exponentially in the number of…

Quantum Physics · Physics 2013-05-29 Robert Koenig , Stephanie Wehner

We present an experiment demonstrating entanglement-enhanced classical communication capacity of a quantum channel with correlated noise. The channel is modelled by a fiber optic link exhibiting random birefringence that fluctuates on a…

Quantum Physics · Physics 2007-05-23 K. Banaszek , A. Dragan , W. Wasilewski , C. Radzewicz

The optimal rate of reliable communication over a quantum channel can be enhanced by pre-shared entanglement. Whereas the enhancement may be unbounded in infinite-dimensional settings even when the input power is constrained, a…

It has recently been shown that there are efficient algorithms for quantum computers to solve certain problems, such as prime factorization, which are intractable to date on classical computers. The chances for practical implementation,…

Quantum Physics · Physics 2009-10-30 Adriano Barenco , Todd A. Brun , Ruediger Schack , Tim Spiller

Noisy quantum channels may be used in many information carrying applications. We show that different applications may result in different channel capacities. Upper bounds on several of these capacities are proved. These bounds are based on…

Quantum Physics · Physics 2009-10-30 Howard Barnum , M. A. Nielsen , Benjamin Schumacher

We provide a model to study memory effects in quantum Gaussian channels with additive classical noise over an arbitrary number of uses. The correlation among different uses is introduced by contiguous two-mode interactions. Numerical…

Quantum Physics · Physics 2007-05-23 Giovanna Ruggeri , Stefano Mancini

We characterize the behavior of quantum correlations under the influence of local noisy channels. Intuition suggests that such noise should be detrimental for quantumness. When considering qubit systems, we show for which channel this is…

Quantum Physics · Physics 2011-10-18 Alexander Streltsov , Hermann Kampermann , Dagmar Bruß

We give a short proof that the coherent information is an achievable rate for the transmission of quantum information through a noisy quantum channel. Our method is to produce random codes by performing a unitarily covariant projective…

Quantum Physics · Physics 2016-11-17 Patrick Hayden , Michal Horodecki , Andreas Winter , Jon Yard

The implementation of realistic quantum devices requires a solid understanding of the nonlocal resources present in quantum channels, and the effects of decoherence on them. Here we quantify nonlocality of bipartite quantum channels and…

Quantum Physics · Physics 2024-08-21 Albert Rico , Moisés Bermejo Morán , Fereshte Shahbeigi , Karol Życzkowski

Classical simulations of noisy quantum circuits are instrumental to our understanding of the behavior of real-world quantum systems and the identification of regimes where one expects quantum advantage. In this work, we present a highly…

Quantum Physics · Physics 2026-02-17 Simon Cichy , Paul K. Faehrmann , Lennart Bittel , Jens Eisert , Hakop Pashayan

Fault-tolerant capacities quantify the ability of a quantum channel to reliably transmit information when every component of the encoding and decoding procedure is noisy. Earlier work analyzed achievable communication rates under such noise…

Quantum Physics · Physics 2026-02-11 Paula Belzig , Hayata Yamasaki

The simplest building blocks for quantum computations are the qubit-qubit quantum channels. In this paper, we analyze the structure of these channels via their Choi representation. The restriction of a quantum channel to the space of…

Mathematical Physics · Physics 2023-07-24 Attila Lovas , Attila Andai

The qubit (or a system of two quantum dots) has become a standard paradigm for studying quantum information processes. Our focus is Decoherence due to interaction of the qubit with its environment, leading to noise. We consider quantum…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Ebad Kamil , Sushanta Dattagupta