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Quantum channels and their entropic characteristics
Reports on Progress in Physics. 2012. Vol. 75. P. 046001.
Holevo A., Giovannetti V.
One of the major achievements of the recently emerged quantum information theory is the introduction and thorough investigation of the notion of quantum channel which is a basic building block of any data-transmitting or data-processing system. This development resulted in an elaborated structural theory and was accompanied by the discovery of a whole spectrum of entropic quantities, notably the channel capacities, characterizing information-processing performance of the channels. This paper gives a survey of the main properties of quantum channels and of their entropic characterization, with a variety of examples for finite dimensional quantum systems. We also touch upon the ``continuous-variables'' case, which provides an arena for quantum Gaussian systems. Most of the practical realizations of quantum information processing were implemented in such systems, in particular based on principles of quantum optics. Several important entropic quantities are introduced and used to describe the basic channel capacity formulas. The remarkable role of the specific quantum correlations -- entanglement -- as a novel communication resource, is stressed.
Shabanov N., Kuricheva O., Kurbatova J. et al., / Series Working Papers SSRN "Department of Economics Ca’ Foscari University of Venice". 2026.
The carbon balance of an ecosystem is the difference between Gross Primary Productivity (GPP) and Ecosystem Respiration (Reco) as expressed by Net Ecosystem Exchange (NEE). While remote sensing retrievals of GPP have reached maturity, Reco estimation remains underexplored and ultimately cast bias on NEE. Here we present an end-to-end multi-scale analysis of the mechanism of ...
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Ponomarenko A., / Series Computer Science "arxiv.org". 2025.
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Added: July 30, 2026
Loubenets E. R., / Series arxiv.org "quant-ph". 2026. No. 2607.18050.
In many quantum applications it is important to know whether or not a Bell nonlocal two-qudit state exhibits its nonlocality under correlation scenarios with some given numbers S1,S2≥1 of generalized quantum measurements at two sites. In the present article, we find analytically a new general locality condition sufficient for a nonseparable Werner state with a ...
Added: July 21, 2026
Piontkovski D., / Series arXiv "math". 2026.
A noncommutative projective variety is defined, following Artin and Zhang, by a graded coherent algebra 𝐴. The category of coherent sheaves is then the quotient qgr(𝐴) of the category of finitely presented graded modules by the subcategory of torsion modules. We consider the categorical and polynomial entropies of the Serre twist, that is, of the ...
Added: June 23, 2026
Piontkovski D., / Series arXiv "math". 2025.
If a symmetric multilinear algebra is weakly nil, then it is Engel. This result may be regarded as an infinite-dimensional analogue of the well-known Jacobian theorem, which states that if a polynomial mapping has a polynomial inverse, then its Jacobian matrix is invertible. This refines a theorem of Gerstenhaber and partially answers a question posed ...
Added: June 23, 2026
Chryssomalakos C., Flores-Delgado A. G., Guzman Gonzalez E. et al., Physical Review A: Atomic, Molecular, and Optical physics 2026 Vol. 113 Article L060404
Added: June 3, 2026
Shipilov F., Barnyakov A., Ivanov A. et al., / Series Physics "arxiv.org". 2026.
A fast simulation of the detector response is a vital task in high-energy physics (HEP). Traditional Monte-Carlo methods form the backbone of modern particle physics simulation software but are computationally expensive. We present a machine-learning-based approach to fast simulation of the Focusing Aerogel Ring Imaging Cherenkov (FARICH) detector response. Given a particle track and momentum, ...
Added: May 19, 2026
Derkacheva A., Sakirkina M., Kraev G. et al., /. 2026.
Comprehensive data on natural hazards and their consequences are crucial for effective for risk assessment, adaptation planning, and emergency response. However, many countries face challenges with fragmented, inconsistent, and inaccessible data, particularly regarding local-scale events. To address this data gap in Russia, we developed an end-to-end processing pipeline that scrapes news from various online sources, ...
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Pilé I., Deng Y., Shchur L., / Series arXiv "math". 2026. No. 2604.10254.
We investigate the spatial overlap of successive spin configurations in Markov chain Monte Carlo simulations using the local Metropolis algorithm and the Svendsen-Wang and Wolff cluster algorithms. We examine the dynamics of these algorithms for two models in different universality classes: the Ising model and the Potts model with three components. The overlap of two ...
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Gabdullin N., Androsov I., / Series Computer Science "arxiv.org". 2026.
Label prediction in neural networks (NNs) has O(n) complexity proportional to the number of classes. This holds true for classification using fully connected layers and cosine similarity with some set of class prototypes. In this paper we show that if NN latent space (LS) geometry is known and possesses specific properties, label prediction complexity can ...
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Sorokin K., Beketov M., Онучин А. et al., / arxiv.org. Серия cs.SI "Social and Information Networks ". 2025.
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Petrovanov I., Sergeev A., / Series Computer Science "arxiv.org". 2025. No. 2512.18332.
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Hessian-based lightweight neural network for brain vessel segmentation on a minimal training dataset
Меньшиков И. А., Бернадотт А. К., Elvimov N. S., / Series arXie "Statistical mechanics". 2025.
Accurate segmentation of blood vessels in brain magnetic resonance angiography (MRA) is essential for successful surgical procedures, such as aneurysm repair or bypass surgery. Currently, annotation is primarily performed through manual segmentation or classical methods, such as the Frangi filter, which often lack sufficient accuracy. Neural networks have emerged as powerful tools for medical image ...
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Lankin A. V., Norman G., Russian Journal of Physical Chemistry A 2025 Vol. 99 No. 11 P. 2833–2904
We present the current state of quantum mechanics, the prospects for its development, and the
strengthening of its influence on scientific and technological progress. We look at quantum mechanics from
four perspectives. The first perspective astonished physicists already with the advent of quantum mechanics—
it is (1) a new way of looking at the world. Over the course ...
Added: November 20, 2025
Бахшалиев Р. М., Reutov A., Vorobey S. et al., Review of Scientific Instruments 2025 Vol. 96 No. 3
One of the main issues of the satellite-to-ground optical communication, including free-space satellite quantum key distribution (QKD), is an achievement of the reasonable accuracy of positioning, navigation, and optical stabilization. Proportional–integral–derivative (PID) controllers can handle various control tasks in optical systems. Recent research shows the promising results in the area of composite control systems including ...
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Elena R. Loubenets, Louis Hanotel, Physical Review A: Atomic, Molecular, and Optical physics 2024 Vol. 110 No. 3 Article 032410
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Added: September 11, 2024
Elena R. Loubenets, Louis Hanotel, / Series arxiv/org "quant-ph". 2024. No. https://arxiv.org/abs/2403.09342.
The geometric quantum discord of a two-qudit state has been studied in many papers, but up to now, its exact analytical value in the explicit form is known only for a general two-qubit state and some specific classes of two-qudit states. Based on the general Bloch vectors formalism [J. Phys. A: Math. Theor. 54 195301 ...
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K S Kravtsov, Laser Physics Letters 2023 Vol. 20 No. 8 Article 085203
The paper analyzes security aspects of practical entanglement-based quantum key distribution
(QKD), namely, BBM92 or entanglement-based BB84 protocol. Similar to prepare-and-measure
QKD protocols, practical implementations of the entanglement-based QKD have to rely upon nonideal
photon sources. A typical solution for entanglement generation is the spontaneous parametric
down-conversion. However, this process creates not only single photon pairs, but also quantum
states ...
Added: March 12, 2024
Vinetskaya P. M., Kravtsov K. S., Borshchevskaia N. A. et al., Laser Physics Letters 2023 Vol. 20 No. 5 Article 055201
Entangled quantum key distribution (QKD) is a promising way to generate pairs of unconditionally secret keys. In this paper we review possible realizations of entanglement-based QKD and assess their feasibility in terms of implementation complexity and provided security. We also propose a novel active basis choice approach that enables to use only one single-photon detector ...
Added: March 12, 2024
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For the maximal violation of all Bell inequalities by an arbitrary pure two-qudit state of any dimension, we derive a new lower bound expressed via the concurrence of this pure state. This new lower bound and the upper bound on the maximal Bell violation, found in [J. Phys. A: Math. Theor. 55, 285301 (2022)] and ...
Added: January 6, 2024
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Entangled photon pairs are key to many novel applications in quantum technologies. Semiconductor quantum dots can be used as sources of on-demand, highly entangled photons. The fidelity to a fixed maximally entangled state is limited by the excitonic fine-structure splitting. This work demonstrates that, even if this splitting is absent, the degree of entanglement cannot ...
Added: December 1, 2022
Pashin D., Bastrakova M., Arkady Satanin et al., Sensors 2022 Vol. 22 No. 17 Article 6580
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Added: October 26, 2022
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Cosacchi M., Seidelmann T., Cygorek M. et al., Physical Review Letters 2021 Vol. 127 No. 10 Article 100402
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Added: September 26, 2021