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Capacities of quantum channels and decoherence times both quantify the extent to which quantum information can withstand degradation by interactions with its environment. However, calculating capacities directly is known to be intractable…

Quantum Physics · Physics 2021-06-07 Ivan Bardet , Marius Junge , Nicholas LaRacuente , Cambyse Rouzé , Daniel Stilck França

A complete degradability analysis of one-mode Gaussian Bosonic channels is presented. We show that apart from the class of channels which are unitarily equivalent to the channels with additive classical noise, these maps can be…

Quantum Physics · Physics 2009-11-13 F. Caruso , V. Giovannetti , A. S. Holevo

We introduce and analyse the problem of encoding classical information into different resources of a quantum state. More precisely, we consider a general class of communication scenarios characterised by encoding operations that commute…

Quantum Physics · Physics 2022-08-08 Kamil Korzekwa , Zbigniew Puchała , Marco Tomamichel , Karol Życzkowski

The strong capacity of a particular channel can be interpreted as a sharp limit on the amount of information which can be transmitted reliably over that channel. To evaluate the strong capacity of a particular channel one must prove both…

Quantum Physics · Physics 2011-10-20 Tony Dorlas , Ciara Morgan

We study the quantum transport through entropic barriers induced by hardwall constrictions of hyperboloidal shape in two and three spatial dimensions. Using the separability of the Schrodinger equation and the classical equations of motion…

Chaotic Dynamics · Physics 2015-05-13 R. Hales , H. Waalkens

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 channel capacities are fundamental to quantum information theory. Their definition, however, does not limit the computational resources of sender and receiver. In this work, we initiate the study of computational quantum capacities.…

Quantum Physics · Physics 2026-01-23 Johannes Jakob Meyer , Jacopo Rizzo , Asad Raza , Lorenzo Leone , Sofiene Jerbi , Jens Eisert

The thermodynamic resourcefulness of quantum channels primarily depends on their underlying causal structure and their ability to generate quantum correlations. We quantify this interplay within the resource theory of athermality for…

Quantum Physics · Physics 2026-04-02 Himanshu Badhani , Siddhartha Das

We provide a simple and realistic model to study memory effects in a lossy bosonic quantum channel over arbitrary number of uses. The noise correlation among different uses is introduced by contiguous modes interactions which results in an…

Quantum Physics · Physics 2009-11-13 O. V. Pilyavets , V. G. Zborovskii , S. Mancini

The causal structure of a stochastic process can be more efficiently transmitted via a quantum channel than a classical one, an advantage that increases with codeword length. While previously difficult to compute, we express the quantum…

Quantum Physics · Physics 2016-05-25 Paul M. Riechers , John R. Mahoney , Cina Aghamohammadi , James P. Crutchfield

Designing encoding and decoding circuits to reliably send messages over many uses of a noisy channel is a central problem in communication theory. When studying the optimal transmission rates achievable with asymptotically vanishing error…

Quantum Physics · Physics 2024-11-07 Matthias Christandl , Alexander Müller-Hermes

The discrete memoryless interference channel is modelled as a conditional probability distribution with two outputs depending on two inputs and has widespread applications in practical communication scenarios. In this paper, we introduce…

Quantum Physics · Physics 2015-03-19 Ivan Savov , Omar Fawzi , Mark M. Wilde , Pranab Sen , Patrick Hayden

We outline a quantum convolutional coding technique for protecting a stream of classical bits and qubits. Our goal is to provide a framework for designing codes that approach the ``grandfather'' capacity of an entanglement-assisted quantum…

Quantum Physics · Physics 2008-10-20 Mark M. Wilde , Todd A. Brun

High-dimensional entanglement with spatial modes of light promises increased security and information capacity over quantum channels. Unfortunately, entanglement decays due to perturbations, corrupting quantum links which cannot be repaired…

In this paper we study Spectral Decomposition Theorem [1] and translate it to quantum language by means of the Wigner transform. We obtain a quantum version of Spectral Decomposition Theorem (QSDT) which enables us to achieve three distinct…

Mathematical Physics · Physics 2014-11-11 Ignacio Gomez , Mario Castagnino

We construct a universal code for stationary and memoryless classical-quantum channel as a quantum version of the universal coding by Csisz\'{a}r and K\"{o}rner. Our code is constructed by the combination of irreducible representation, the…

Quantum Physics · Physics 2011-06-24 Masahito Hayashi

It is well known that quantum theory forbids the exact copying of an unknown quantum state. Therefore in broadcasting of classical information by a quantum channel an additional contribution to the error in the decoding is expected. We…

Quantum Physics · Physics 2007-05-23 A. E. Allahverdyan , D. B. Saakian

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

Channel conversion constitutes a pivotal paradigm in information theory and its applications to quantum physics, providing a unified problem setting that encompasses celebrated results such as Shannon's noisy-channel coding theorem. Quantum…

Quantum Physics · Physics 2025-09-10 Masahito Hayashi , Hayata Yamasaki

This paper is essentially a lecture from the author's course on quantum information theory, which is devoted to the result of C. H. Bennett, P. W. Shor, J. A. Smolin and A. V. Thapliyal (quant-ph/0106052) concerning entanglement-assisted…

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