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Channel-state duality is a central result in quantum information science. It refers to the correspondence between a dynamical process (quantum channel) and a static quantum state in an enlarged Hilbert space. Since the corresponding dual…

Quantum Physics · Physics 2022-10-10 Bin Yan , Nikolai A. Sinitsyn

Communication over a random-parameter quantum channel when the decoder is required to reconstruct the parameter sequence is considered. We study scenarios that include either strictly-causal, causal, or non-causal channel side information…

Information Theory · Computer Science 2021-09-28 Uzi Pereg

Quantum hypothesis testing is a central task in the entire field of quantum information theory. Understanding its ultimate limits will give insight into a wide range of quantum protocols and applications, from sensing to communication.…

Quantum Physics · Physics 2020-11-18 Quntao Zhuang , Stefano Pirandola

An expression is derived characterizing the set of admissible rate pairs for simultaneous transmission of classical and quantum information over a given quantum channel, generalizing both the classical and quantum capacities of the channel.…

Quantum Physics · Physics 2007-05-23 I. Devetak , P. W. Shor

Gaussian quantum channels are relevant operations in continuous variable systems. In general, given an arbitrary state, the action on it is well-known provided that the quantum channels are completely characterized. In this work, we…

Quantum Physics · Physics 2025-05-20 Jonas F. G. Santos , Carlos H. S. Vieira , Wilder R. Cardoso

Quantum transport on structured networks is strongly influenced by interference effects, which can dramatically modify how information propagates through a system. We develop a quantum-information-theoretic framework for scattering on…

Quantum Physics · Physics 2026-01-29 Giuseppe Catalano , Farzad Kianvash , Vittorio Giovannetti

The decoherence rate is a nonlinear channel parameter that describes quantitatively the decay of the off-diagonal elements of a density operator in the decoherence basis. We address the question of how to experimentally access such a…

Quantum Physics · Physics 2012-11-14 Vladimír Bužek , Peter Rapcan , Jochen Rau , Mario Ziman

We introduce a new framework for quantum channel discrimination in an adversarial setting, where the tester plays against an adversary. We show that in asymmetric hypothesis testing, the optimal type-II error exponent is precisely…

Quantum Physics · Physics 2026-01-01 Kun Fang , Hamza Fawzi , Omar Fawzi

A channel $W$ is said to be input-degraded from another channel $W'$ if $W$ can be simulated from $W'$ by randomization at the input. We provide a necessary and sufficient condition for a channel to be input-degraded from another one. We…

Information Theory · Computer Science 2017-02-03 Rajai Nasser

Quantum entropy inequalities are studied. Some quantum entropy inequalities are obtained by several methods. For entanglement breaking channel, we show that the entanglement-assisted classical capacity is upper bounded by $\log d$. A…

Quantum Physics · Physics 2009-11-07 Heng Fan

It is shown that, if the loss of entanglement along a quantum channel is sufficiently small, then approximate quantum error correction is possible, thereby generalizing what happens for coherent information. Explicit bounds are obtained for…

Quantum Physics · Physics 2008-01-15 Francesco Buscemi

Establishing quantum correlations between two remote parties by sending an information carrier is an essential step of many protocols in quantum information processing. We obtain trade-off relations between discords and coherence within a…

Quantum Physics · Physics 2022-03-25 Zhi-Xiang Jin , Xianqing Li-Jost , Shao-Ming Fei , Cong-Feng Qiao

One of the basic tenets in information theory, the data processing inequality states that output divergence does not exceed the input divergence for any channel. For channels without input constraints, various estimates on the amount of…

Information Theory · Computer Science 2015-08-14 Yury Polyanskiy , Yihong Wu

The noisiness of a channel can be measured by comparing suitable functionals of the input and output distributions. For instance, the worst-case ratio of output relative entropy to input relative entropy for all possible pairs of input…

Information Theory · Computer Science 2016-03-31 Maxim Raginsky

Quantum channels, pivotal in information processing, describe transformations within quantum systems and enable secure communication and error correction. Ergodic and mixing properties elucidate their behavior. In this paper, we establish a…

Quantum Physics · Physics 2024-07-24 Abdessatar Souissi , Abdessatar Barhoumi

Compatibility conditions of quantum channels featuring symmetry through covariance are studied. Compatibility here means the possibility of obtaining two or more channels through partial trace out of a broadcasting channel. We see that…

Quantum Physics · Physics 2019-10-02 Erkka Haapasalo

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

Quantum networks entangle remote nodes by distributing quantum states, which inevitably suffer from decoherence while traversing quantum channels. Pertinent decoherence mechanisms govern the channel capacity, its reach, and the quality and…

Quantum Physics · Physics 2018-11-08 Daniel E. Jones , Brian T. Kirby , Michael Brodsky

For a pair of quantum channels with the same input space, we show that the possibility of approximation of one channel by post-processings of the other channel can be characterized by comparing the success probabilities for the two…

Quantum Physics · Physics 2016-04-26 Anna Jencova

For a pair of quantum channels with the same input space, we show that the possibility of approximation of one channel by post-processings of the other channel can be characterized by comparing the success probabilities for the two…

Quantum Physics · Physics 2016-04-26 Anna Jencova