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Quantum systems, channels, information. A mathematical introduction
Berlin :
De Gruyter, 2013.
A. S. Holevo
The subject of this book is theory of quantum system presented from information science perspective. The central role is played by the concept of quantum channel and its entropic and information characteristics. Quantum information theory gives a key to understanding elusive phenomena of quantum world and provides a background for development of experimental techniques that enable measuring and manipulation of individual quantum systems. This is important for the new efficient applications such as quantum computing, communication and cryptography. Research in the field of quantum informatics, including quantum information theory, is in progress in leading scientific centers throughout the world. This suggests a need for a text that not only introduces the basic concepts of quantum information theory, but also presents in detail some of its recent achievements. The book gives an accessible, albeit mathematically rigorous and self-contained introduction to the subject, starting from primary structures and leading to fundamental results and to exiting open problems.
Ponomarenko A., / Series Computer Science "arxiv.org". 2025.
This paper addresses the challenge of merging hierarchical navigable small world (HNSW) graphs, a critical operation for distributed systems, incremental indexing, and database compaction. We propose three algorithms for this task: Naive Graph Merge (NGM), Intra Graph Traversal Merge (IGTM), and Cross Graph Traversal Merge (CGTM). These algorithms differ in their approach to vertex selection ...
Added: July 30, 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
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, ...
Added: April 28, 2026
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 ...
Added: April 20, 2026
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 ...
Added: April 2, 2026
Sorokin K., Beketov M., Онучин А. et al., / arxiv.org. Серия cs.SI "Social and Information Networks ". 2025.
Community detection in complex networks is a fundamental problem, open to new approaches in various scientific settings. We introduce a novel community detection method, based on Ricci flow on graphs. Our technique iteratively updates edge weights (their metric lengths) according to their (combinatorial) Foster version of Ricci curvature computed from effective resistance distance between the ...
Added: January 15, 2026
Petrovanov I., Sergeev A., / Series Computer Science "arxiv.org". 2025. No. 2512.18332.
Transport coding reduces message delay in packet-switched networks by introducing controlled redundancy at the transport layer: original packets are encoded into coded packets, and the message is reconstructed after the first successful deliveries, effectively shifting latency from the maximum packet delay to the -th order statistic. We present a concise, reproducible discrete-event implementation of transport coding in OMNeT++, including ...
Added: December 24, 2025
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 ...
Added: December 1, 2025
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
Rubchinskiy A., Chubarova D., / Series WP7 "Математические методы анализа решений в экономике, бизнесе и политике". 2025. No. WP7/2025/01.
The article examines one of the most famous examples of socio-economic systems, characterized by significant uncertainty – the S&P-500 stock market, where shares of 500 largest US companies are traded. No assumptions are made about the probabilistic characteristics of the stock market. A flexible algorithm for daily trading has been developed, based on both known fixed data ...
Added: November 9, 2025
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
Смирнов И. А., Черкесова Л. В., Бабаян М. Г. et al., Международный журнал прикладных и фундаментальных исследований 2019 № 7 С. 93–99
Over the past decades, new physical effects have been applied to the construction of standards: the Josephson
quantum effect, the quantum Hall effect, the Meissner effect, the Mossbauer effect, and others. and Hall. The
development of quantum Josephson circuits has created high hopes for reliable processing of quantum information.
Despite the fact that this progress has already led ...
Added: May 10, 2023
Seidelman T., Schimpf C., Bracht T. et al., Physical Review Letters 2022 Vol. 129 No. 19 Article 193604
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
We study bifurcation behavior of a high-quality (high-Q) Josephson oscillator coupled to a superconducting qubit. It is shown that the probability of capture into the state of dynamic equilibrium is sensitive to qubit states. On this basis we present a new measurement method for the superposition state of a qubit due to its influence on ...
Added: October 26, 2022
Seidelmann T., Cosacchi M., Cygorek M. et al., Advanced Quantum Technologies 2021 Vol. 4 No. 1 Article 2000108
Bell states are the most prominent maximally entangled photon states. In a typical four-level emitter, like a semiconductor quantum dot, the photon states exhibit only one type of Bell state entanglement. By adding an external driving to the emitter system, also other types of Bell state entanglement are reachable without changing the polarization basis. In ...
Added: February 24, 2022
M V Fedorov, Physica Scripta 2020 Vol. 95 No. 6 Article 064001
Schmidt-decomposition formalism is proposed to be used for evaluation of the degree of
quadrature entanglement in two-mode multiphoton states. A series of examples are considered,
including analysis of the quadrature entanglement of the two-mode squeezed vacuum. Singlemode
and two-mode coherent states with stochastic phases are analyzed by the same method
though in this case features of quadrature states are ...
Added: April 6, 2021
Akulin, Physical Review A (USA) 2015 Vol. 92 No. 4
Using geometric means, we first consider a density matrix decomposition of a multipartite quantum system of a finite dimension into two density matrices: a separable one, also known as the best separable approximation, and an essentially entangled one, which contains no product state components. We show that this convex decomposition can be achieved in practice ...
Added: November 1, 2020
Дыренков В. С., Шевель Н. М., Ivanov F. et al., Информационные процессы 2020 Т. 20 № 2 С. 133–141
In this paper, we consider a vector disjunctive channel in which users transmit some binary vectors of
length L. We estimate the capacity of this channel and derive a lower bound on this value. In addition, the
lower bound is calculated both for the case of the Bernoulli distribution and for an arbitrary distribution for
the case when ...
Added: October 6, 2020
Ivanov F., Rybin P., Afanassiev V. et al., , in: 2019 XVI International Symposium "Problems of Redundancy in Information and Control Systems" (REDUNDANCY).: IEEE, 2019. P. 27–31.
Added: March 17, 2020
M V Fedorov, Laser Physics 2019 Vol. 29 No. 12 Article 124006
A brief overview of entanglement characterization is given in the cases of biphoton and
multiphoton polarization states. The importance of the approach is stressed based on the
Schmidt decomposition. This method is applied to the characterization of the quadrature
entanglement in two-mode multiphoton states. The fruitfulness of this approach is illustrated
by a series of examples. ...
Added: December 3, 2019
Ivanov F., Kreshchuk A., Rybin P. et al., , in: The 11th International Congress on Ultra Modern Telecommunications and Control Systems (ICUMT 2019).: Dublin: IEEE, 2019. P. 1–5.
Added: October 1, 2019