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Security of entanglement-based QKD with realistic parametric down-conversion sources
Laser Physics Letters. 2023. Vol. 20. No. 8. Article 085203.
K S Kravtsov
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 with more than two photons, which potentially may lead to security deterioration. We show
that this effect does not impair the security of entanglement-based QKD systems. We also review
the available security proofs and show that properties of the entanglement source have nothing to
do with security degradation.
Никонов В. Д., Никитин С. С., Патракеев М. В., Ionics 2025 Vol. 31 No. 1 P. 675–687
Modification of perovskite-type oxides is an effective way to develop functional materials with advanced properties. The effects of cerium introduction into the A sublattice of La0.5Sr0.5FeO3−δ and variation of La:Sr ratio on the defect structure and charge transfer characteristics were studied in this work. The LaxSr0.85−xCe0.15FeO3−δ oxides were found to be single-phase with cubic (x = 0.1) and orthorhombic ...
Added: June 26, 2026
Polkin A., Skvortsov M., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 113 Article 174516
We develop a full microscopic theory for the optical conductivity 𝜎(𝜔) of a dirty current-carrying superconductor. Within the Keldysh sigma model formalism, we obtain the general analytical expression for 𝜎(𝜔), applicable for arbitrary frequency 𝜔, temperature 𝑇, and dc supercurrent 𝐼. In addition to altering the usual Mattis-Bardeen conductivity 𝜎1(𝜔), a finite supercurrent introduces two new contributions: 𝜎qp2(𝜔) from quasiparticle redistribution and 𝜎SH2(𝜔) from the amplitude ...
Added: June 25, 2026
Skvortsov M., Artem Polkin, Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 113 No. 10 Article 100502
A dissipationless supercurrent state in superconductors can be destroyed by thermal fluctuations. Thermally activated phase slips provide a finite resistance of the sample and are responsible for dark counts in superconducting single-photon detectors. The activation barrier for a phase slip is determined by a space-dependent saddle-point (instanton) configuration of the order parameter. In the one-dimensional ...
Added: June 25, 2026
Деменев А. А., Терешко С. Н., Гиппиус Н А et al., Известия РАН. Серия физическая Россия 2025 Т. 89 № 2 С. 265–273
The authors study the temporal evolution of polarized spectra of emissions from spinor exciton‒
polariton condensates in double tunnel-coupled potential traps inside a high-Q GaAs/AlAs microcavity
at 2 K upon resonance laser pumping with picosecond pulses at times of up to 1.5 ns. The period of the condensates’
spin relaxation in a double trap is estimated as τs ...
Added: June 23, 2026
Абрамов-Максимов В. Е., И.А. Бакунина, Геомагнетизм и аэрономия 2026 Т. 66 № 3 С. 515–529
Проанализировано 8 вспышечных событий по данным многочастотных наблюдений сети радиотелескопов Radio Solar Telescope Network. Целью анализа было выявление предвестников солнечных вспышек. В семи рассмотренных случаях выявлены предвспышечные квазипериодические флуктуации радиоизлучения. Сделанная по вейвлет-спектрам оценка квазипериодов дает в большинстве случаев значения 40–50 сек. В одном событии с большой вспышкой класса M8.0 квазипериодические флуктуации не проявились. В ...
Added: June 22, 2026
И.А. Бакунина, В.Ф. М., А.В. Ш. et al., Геомагнетизм и аэрономия 2025 Т. 65 № 9 С. 1363–1373
Рассмотрена связь особенностей положения и ориентации магнитных жгутов в активной области (АО) с источниками микроволнового (17 ГГц) излучения и излучения в крайнем ультрафиолетовом диапазоне (EUV) при возникновении эруптивных вспышек, сопровождающихся корональными выбросами массы, и вспышек с "запертой" эрупцией. Приведены примеры эруптивных событий, демонстрирующие пространственное совпадение микроволновых источников с расположением магнитных жгутов в АО, восстановленных при ...
Added: June 22, 2026
Г. Г. Бондаренко, Кристя В. И., Савичкин Д. О. et al., Поверхность. Рентгеновские, синхротронные и нейтронные исследования 2026 № 4 С. 29–36
Сформулирована модель тлеющего газового разряда в смеси аргона и паров ртути при наличии
на поверхности катода тонкой диэлектрической пленки. Рассчитаны зависимости характеристик
разряда от температуры в интервале ее изменения, в котором заметный вклад в ионизацию
рабочей газовой смеси дает ионизация атомов ртути метастабильными возбужденными атомами
аргона (реакция Пеннинга). Показано, что в случае катода без диэлектрической пленки при
повышении температуры до ...
Added: June 20, 2026
Chertenkov V. I., Shchur L., Lobachevskii Journal of Mathematics 2026 Vol. 47 No. 2 P. 720–727
Supervised machine learning is successfully applied to the study of critical phenomena and allows us to obtain a numerical estimate of the phase transition temperature and the correlation length exponent. We discuss the influence of possible systematic errors, as well as statistical errors, on the accuracy of such numerical estimates. Errors in the training and ...
Added: June 16, 2026
Батурин А. С., Гаврилов В. Р., Иванов А. В. et al., Измерительная техника 2026 Т. 75 № 2 С. 14–28
28 декабря 2025 года Всероссийскому научно-исследовательскому институту оптико-физических измерений (ВНИИОФИ) исполнилось 60 лет. За прошедшие десятилетия институт выполнил значительное количество научных исследований, разработал и поставил потребителям тысячи высокоточных средств оптико-физических измерений (включая эталонное оборудование). В статье представлены наиболее значимые для метрологического обеспечения оптико-физических измерений результаты научно-исследовательских работ, выполненных ВНИИОФИ за период 2016–2025 гг. ...
Added: June 15, 2026
Вишняков Г. Н., Левина Э. Ю., Minaev V., Измерительная техника 2025 Т. 74 № 2 С. 20–27
Качество формируемого оптической системой изображения определяется её частотно-контрастной характеристикой или коэффициентами передачи модуляции на различных пространственных частотах. Для обеспечения единства измерений коэффициентов передачи модуляции и создания эталонной базы по воспроизведению, хранению и передаче единицы коэффициента передачи модуляции усовершенствован Государственный первичный эталон единиц оптической силы очковой оптики ГЭТ 205-2013 в части воспроизведения единицы коэффициентов передачи модуляции ...
Added: June 15, 2026
Filippova A. V., Yurchenko N. Y., Smirnov S. A. et al., Journal of Alloys and Compounds 2026 No. 1074 Article 189162
This study investigates the effects of post-processing heat treatment at 300–500 °C on the microstructure, hardness, and tensile properties of laser powder bed fusion (PBF-LB) processed Al-bronze processed with energy densities (ED) in the range of 125–938 J/mm3. In the as-printed state, sharp needle-like α + β′ laths form at lower ED whereas with increasing ED, the β′ ...
Added: June 12, 2026
Спонтанное образование скин-слоя в воде с деформацией ОН-полосы КР вкладом компоненты льда 3200 см-1
Першин С. М., Степанов Е. В., Артемова Д. Г. et al., Письма в Журнал экспериментальной и теоретической физики 2026 Т. 123 № 6 С. 383–390
Открыто спонтанное образование в течение 4 ч скин-слоя дистиллированной воды толщиной до 3 мм при комнатной температуре с новыми свойствами. Обнаружены деформация ОН-полосы комбинационного рассеяния вкладом компоненты льда ( 3200 см-1), снижение коэффициента упругого рассеяния и его флуктуаций, а также увеличение на 20 капиллярах. Восстановление слоя после обогащения воздухом в результате перемешивания указывает на стабильность ...
Added: June 8, 2026
Springer, 2026.
The book presents the proceedings of the 13th International Conference on Frontiers of Intelligent Computing: Theory and Applications (FICTA 2024), held at Intelligent Systems Research Group (ISRG), London Metropolitan University, London, United Kingdom, during June 6–7, 2025. Researchers, scientists, engineers and practitioners exchange new ideas and experiences in the domain of intelligent computing theories with ...
Added: June 8, 2026
N.S. Artekha, D.R. Shklyar, Physics of Plasmas 2026 Vol. 33 No. 6 Article 062105
The peculiarities of resonant interaction between slow extraordinary (SE) waves and relativistic electrons have been studied. General equations of motion of relativistic electrons in the field of SE wave and a uniform ambient magnetic field are derived. Conditions of applicability of the isolated resonance approximation are elucidated. In this approximation, the equations of motion are reduced to one-dimensional set of ...
Added: June 6, 2026
Zirnik G., Ostovari Moghaddam A., Zhukov S. et al., Journal of Materials Science: Materials in Electronics 2026 Vol. 37 Article 738
In regards to the advances in InGaZnO for flexible transistors applications, herein for the first time we measure the broadband radio-frequency range (10 Hz to 1 MHz) dielectric permittivity ε′ and electrical conductivity σ of InGaZnO4 nanoparticle layers at different temperatures ranging from 10 to 300 K. The InGaZnO4 nanoparticles prepared by metal–nitrate–glycol gel decomposition method exhibited ...
Added: June 6, 2026
Flamarion M. V., Pelinovsky E., Nonlinear Dynamics 2026 Vol. 114 Article 784
In this article, we investigate wave packet and solitary wave dynamics in the Whitham–Ostrovsky (WO) equation. By means of a multiple-scales expansion, we formally derive a nonlinear Schrödinger (NLS) equation governing the envelope evolution.The corresponding modulational stability diagram is then obtained using the Lighthill criterion. We show that sufficiently large values of the low-frequency dispersive term render ...
Added: June 5, 2026
Hazarika A. P., Das A., Das S. K. et al., Physica B: Condensed Matter 2026 Vol. 738 Article 418803
Lemon grass (Cymbopogon citratus, LG-SiO2), horsetail (Equisetum debile, SG-SiO2), and cassava leaves (Manihot esculenta, CL-SiO2) were used to green-synthesize silica (SiO2) nanoparticles (NPs). While LG-SiO2 and SG-SiO2 had strong (101) peaks and a large 22° amorphous peak, XRD of CL-SiO2 verified crystallinity. LG-SiO2 (agglomerated porous), SG-SiO2 (rectangular-cube agglomerates), and CL-SiO2 (flake agglomerates) had different morphologies. The TEM image of LG-SiO2 revealed agglomerated ...
Added: June 4, 2026
Ponosova A., Zhluktova I., Ruzhitskaya D. et al., Applied Physics Letters 2025 Vol. 127 No. 19 P. 194002
Quantum key distribution systems offer cryptographic security, provided that all their components are thoroughly characterized. However, certain components might be vulnerable to laser-damage attacks, particularly when subjected to untested laser parameters. Here, we show that exposing 1550-nm fiber-optic isolators to 1061-nm sub-nanosecond pulsed illumination with 1.16 W average power permanently degrades their isolation performance at ...
Added: December 5, 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
V. I. Morozov, O. O. Evsyutin, S. I. Nefedov, Problems of Information Transmission 2025 Vol. 61 No. 1 P. 8–26
One of the main applications of quantum communication is quantum key distribution, which solves the problem of secure distribution of cryptographic keys between remote users. This paper investigates the performance of a phase-time coding quantum key distribution protocol belonging to the BB84 protocol family. We construct a simulation model that takes into account the peculiarities ...
Added: April 22, 2025
Makarov V., Abrikosov A., Chaiwongkhot P. et al., Physical Review Applied 2024 Vol. 22 No. 4 P. 044076-1–044076-34
A commercial quantum key distribution (QKD) system needs to be formally certified to enable its wide deployment. The certification should include the system’s robustness against known implementation loopholes and attacks that exploit them. Here we ready a fiber-optic QKD system for this procedure. The system has a prepare-and-measure scheme with decoy-state BB84 protocol, polarization encoding, ...
Added: December 8, 2024
Ruzhitskaya D., Zhluktova I., Ponosova A. et al., Conference on Lasers and Electro-Optics/Europe (CLEO/Europe 2023) and European Quantum Electronics Conference 2023 Article eb_p_14
Quantum key distribution (QKD) systems provide quantum-safe key exchange. Therefore, complete security analysis of implementations of QKD protocols is in the focus of interest of a worldwide information-security community. For today, a number of QKD loopholes are closed by countermeasures, which are also considered in emerging QKD security evaluation and certification [1–3]. However, new threats ...
Added: September 13, 2024
Khmelev A., Duplinsky A, Bakhshaliev R et al., Optics Express 2024 Vol. 32 No. 7 P. 11964–11978
The Micius satellite is the pioneering initiative to demonstrate quantum teleportation, entanglement distribution, quantum key distribution (QKD), and quantum-secured communications experiments at the global scale. In this work, we report on the results of the 600-mm-aperture ground station design which has enabled the establishment of a quantum-secured link between the Zvenigorod and Nanshan ground stations ...
Added: April 25, 2024
Miller A., Pismenuk L., Duplinsky AV et al., EPJ QUANTUM TECHNOLOGY 2023 Vol. 10 No. 1 Article 52
A satellite-constellation based global quantum network could allow secure quantum communication between remote users worldwide. Such a constellation could be formed of micro- or even nanosatellites, which have the advantage of being more cost-effective than larger expensive spacecrafts. At the same time, the features of quantum communication impose a number of technical requirements that are ...
Added: April 25, 2024