Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1307.0014

Optimal Binary Codes and Measurements for Classical Communication over Qubit Channels

Pozza, Nicola Dalla, Nicola Laurenti, Francesco Ticozzi

Published Jun 28, 2013• 0 citations
arXivHTMLPDF

Abstract

We propose constructive approaches for the optimization of binary classical communication over a general noisy qubit quantum channel, for both the error probability and the classical capacity functionals. After showing that the optimal measurements are always associated to orthogonal projections, we construct a parametrization of the achievable transition probabilities via the coherence vector representation. We are then able to rewrite the problem in a form that can be solved by standard, efficient numerical algorithms and provides insights on the form of the solutions.

DOI
10.48550/arxiv.1307.0014

Related papers

Convergence Properties of Good Quantum Codes for Classical Communication

Alptug Aytekin, Mohamed Nomeir, Lei Hu +1 more

An important part of the information theory folklore had been about the output statistics of codes that achieve the capacity and how the empirical distributions compare to the output distributions induced by the optimal input in the channel capacity problem. Results for a variety of such empirical output distributions of good codes have been known in the literature, such as the comparison of the output distribution of the code to the optimal output distribution in vanishing and non-vanishing error probability cases. Motivated by these, we aim to achieve similar results for the quantum codes that are used for classical communication, that is the setting in which the classical messages are communicated through quantum codewords that pass through a noisy quantum channel. We first show the uniqueness of the optimal output distribution, to be able to talk more concretely about the optimal output distribution. Then, we extend the vanishing error probability results to the quantum case, by using techniques that are close in spirit to the classical case. We also extend non-vanishing error probability results to the quantum case on block codes, by using the second-order converses for such codes based on hypercontractivity results for the quantum generalized depolarizing semi-groups.

cs.ITCross-listedarXiv:2601.11498•IEEE International Symposium on Information Theory (ISIT)•Jan 19, 2026•1 citation

Optimal Binary Codes and Measurements for Classical Communication over Qubit Channels

Nicola Dalla Pozza, Nicola Laurenti, Francesco Ticozzi

Developing a suitable geometric representation, we provide algorithmic solutions to the problem of finding pairs of states and measurements that optimize either error probability or mutual information for a given arbitrary qubit channel.

Research in Optical Sciences•Jan 1, 2012•0 citations

Decoding Protocols for Classical Communication on Quantum Channels

Matteo Rosati

We study the problem of decoding classical information encoded on quantum states at the output of a quantum channel, with particular focus on increasing the communication rates towards the maximum allowed by Quantum Mechanics. After a brief introduction to the main theoretical formalism employed in the rest of the thesis, i.e., continuous-variable Quantum Information Theory and Quantum Communication Theory, we consider several decoding schemes. First, we treat the problem from an abstract perspective, presenting a method to decompose any quantum measurement into a sequence of easier nested measurements through a binary-tree search. Furthermore we show that this decomposition can be used to build a capacity-achieving decoding protocol for classical communication on quantum channels and to solve the optimal discrimination of some sets of quantum states. These results clarify the structure of optimal quantum measurements, showing that it can be recast in a more operational and experimentally-oriented fashion. Second, we consider a more practical approach and describe three receiver structures for coherent states of the electromagnetic field with applications to single-mode state discrimination and multi-mode decoding at the output of a quantum channel. We treat the problem bearing in mind the technological limitations faced nowadays in the field of optical communications: we evaluate the performance of general decoding schemes based on such technology and report increased performance of two schemes, the first one employing a non-Gaussian transformation and the second one employing a code tailored to be read out easily by the most common detectors. Eventually we characterize a large class of multi-mode adaptive receivers based on common technological resources, obtaining a no-go theorem for their capacity.

arXiv:1710.08638•Oct 24, 2017•2 citations

Non-binary classical error-correcting codes for quantum communication

Christopher Boyd, Renaud-Alexandre Pitaval, Ülo Parts +1 more

We investigate the use of non-binary classical error-correcting codes in facilitating reliable, entanglement-assisted communication of classical information over quantum depolarising channels. A classical-quantum communication system is presented, which relies on error-correction in the classical domain to achieve an information rate that approaches the entanglement-assisted capacity of the quantum channel. Classical information is transmitted over the channel by means of the superdense coding protocol, and the impact of the noisy distribution of initial entanglement resources on the achievable information rate is considered. In this context, the transmission model is equivalent to a non-binary discrete symmetric classical channel, which motivates the use of non-binary error-correcting codes capable of exploiting correlations between the pairs of classical bits communicated via the superdense coding protocol. We illustrate this principle by showing that duo-binary turbo codes significantly outperform binary turbo codes in the considered scenarios.

International Conference on Communications•Jun 1, 2015•4 citations

Efficient Accessible Bounds to the Classical Capacity of Quantum Channels

Chiara Macchiavello, Massimiliano Federico Sacchi

We present a method to detect lower bounds to the classical capacity of quantum communication channels by means of few local measurements (i.e., without complete process tomography), reconstruction of sets of conditional probabilities, and classical optimization. The method does not require any a priori information about the channel. We illustrate its performance for significant forms of noisy channels.

arXiv:1908.01614•Physical Review Letters•Aug 28, 2019•9 citations

Quantum Cost of Dense Coding of Noisy and Multiple Use of Bell Channels

Tianlang Xing

Dense coding is a basic protocol for quantum information transfer. We study the noisy and multi-use of quantum channels for dense coding protocols. For this purpose, we replace the standard channel, namely the EPR pair by a noisy two-qubit pure state. We construct the measurement Alice carries out to encode her message to be transferred to Bob. It turns out that the resulting states are not all orthogonal, and we propose a probability function for success transfer. We mathematically maximize the function in terms of the quantum measurements taken by Bob. We further develop the protocol to multi-use channels, and investigate the probability function for success transfer.

Theoretical and Natural Science•Jan 15, 2025•0 citations
We propose constructive approaches for the optimization of binary classical communication over a general noisy qubit quantum channel, for both the error probability and the classical capacity functionals. After showing that the optimal measurements are always associated to orthogonal projections, we construct a parametrization of the achievable transition probabilities via the coherence vector representation. We are then able to rewrite the problem in a form that can be solved by standard, efficient numerical algorithms and provides insights on the form of the solutions.
An important part of the information theory folklore had been about the output statistics of codes that achieve the capacity and how the empirical distributions compare to the output distributions induced by the optimal input in the channel capacity problem. Results for a variety of such empirical output distributions of good codes have been known in the literature, such as the comparison of the output distribution of the code to the optimal output distribution in vanishing and non-vanishing error probability cases. Motivated by these, we aim to achieve similar results for the quantum codes that are used for classical communication, that is the setting in which the classical messages are communicated through quantum codewords that pass through a noisy quantum channel. We first show the uniqueness of the optimal output distribution, to be able to talk more concretely about the optimal output distribution. Then, we extend the vanishing error probability results to the quantum case, by using techniques that are close in spirit to the classical case. We also extend non-vanishing error probability results to the quantum case on block codes, by using the second-order converses for such codes based on hypercontractivity results for the quantum generalized depolarizing semi-groups.
We study the problem of decoding classical information encoded on quantum states at the output of a quantum channel, with particular focus on increasing the communication rates towards the maximum allowed by Quantum Mechanics. After a brief introduction to the main theoretical formalism employed in the rest of the thesis, i.e., continuous-variable Quantum Information Theory and Quantum Communication Theory, we consider several decoding schemes. First, we treat the problem from an abstract perspective, presenting a method to decompose any quantum measurement into a sequence of easier nested measurements through a binary-tree search. Furthermore we show that this decomposition can be used to build a capacity-achieving decoding protocol for classical communication on quantum channels and to solve the optimal discrimination of some sets of quantum states. These results clarify the structure of optimal quantum measurements, showing that it can be recast in a more operational and experimentally-oriented fashion. Second, we consider a more practical approach and describe three receiver structures for coherent states of the electromagnetic field with applications to single-mode state discrimination and multi-mode decoding at the output of a quantum channel. We treat the problem bearing in mind the technological limitations faced nowadays in the field of optical communications: we evaluate the performance of general decoding schemes based on such technology and report increased performance of two schemes, the first one employing a non-Gaussian transformation and the second one employing a code tailored to be read out easily by the most common detectors. Eventually we characterize a large class of multi-mode adaptive receivers based on common technological resources, obtaining a no-go theorem for their capacity.
We investigate the use of non-binary classical error-correcting codes in facilitating reliable, entanglement-assisted communication of classical information over quantum depolarising channels. A classical-quantum communication system is presented, which relies on error-correction in the classical domain to achieve an information rate that approaches the entanglement-assisted capacity of the quantum channel. Classical information is transmitted over the channel by means of the superdense coding protocol, and the impact of the noisy distribution of initial entanglement resources on the achievable information rate is considered. In this context, the transmission model is equivalent to a non-binary discrete symmetric classical channel, which motivates the use of non-binary error-correcting codes capable of exploiting correlations between the pairs of classical bits communicated via the superdense coding protocol. We illustrate this principle by showing that duo-binary turbo codes significantly outperform binary turbo codes in the considered scenarios.
Dense coding is a basic protocol for quantum information transfer. We study the noisy and multi-use of quantum channels for dense coding protocols. For this purpose, we replace the standard channel, namely the EPR pair by a noisy two-qubit pure state. We construct the measurement Alice carries out to encode her message to be transferred to Bob. It turns out that the resulting states are not all orthogonal, and we propose a probability function for success transfer. We mathematically maximize the function in terms of the quantum measurements taken by Bob. We further develop the protocol to multi-use channels, and investigate the probability function for success transfer.