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On Controllability of a Highly Degenerate Four-Level Quantum System with a ‘‘Chained’’ Coupling Hamiltonian
Lobachevskii Journal of Mathematics. 2022. Vol. 43. P. 1683–1692.
Kuznetsov S. A., Pechen A. N.
Last decades have faced considerable interest in various problems of quantum control. One of them is to determine which quantum systems are controllable, meaning that all possible states of such systems can be reached from any initial one under available controls. This paper focuses on controllability exploration of a specific four-level quantum system with three levels having the same energy and driven by an electromagnetic control field which allows transitions only between adjacent basis states. Such systems appear in the analysis of higher order traps in quantum control landscapes. This paper explores a few properties of the system, including a proof it is completely controllable for any complex values of the non-zero matrix elements of the interaction Hamiltonian.
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
Medvedev T. V., Pochinka O., Chaos 2026 Vol. 36 No. 6 Article 063107
We consider 3-diffeomorphisms with source–sink dynamics where Smale solenoids play the role of the source and the sink (NSSS-diffeomorphisms). It is known that such diffeomorphisms exist only on lens spaces. On the 3-sphere, every NSSS-diffeomorphism is associated with an exchangeable braid. An exchangeable braid with the strand number n was constructed for each n 3 in such a way ...
Added: June 4, 2026
Kazakov A., Mints D., Petrova I. et al., Chaos 2026 Vol. 36 No. 6 Article 063112
We study hyperbolic chaotic dynamics for maps of a two-dimensional torus. We introduce a two-parameter family of diffeomorphisms which, as we show, demonstrates all types of hyperbolic chaotic dynamics that can appear in the two-dimensional case. In addition, we describe all the bifurcations responsible for the transitions between these chaotic regimes. ...
Added: June 4, 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
Nozdrinova E., Pochinka O., Shmukler V., Математический сборник 2026 Т. 217 № 6 С. 71–89
Гомеоморфизмы топологических пространств называются эквивалентными по надстройке, если надстройки над ними топологически эквивалентны. В частности, топологически сопряженные гомеоморфизмы эквивалентны по надстройке. Известно, что для гомологически неприводимых гомеоморфизмов их топологическая сопряженность является необходимым и достаточным условием их эквивалентности по надстройке. Тогда как инварианты топологической сопряженности гомологически приводимых гомеоморфизмов во многих случаях являются избыточными для эквивалентности по ...
Added: June 3, 2026
Kornbleuth M., Opher M., Drake J. F. et al., Astrophysical Journal 2026 Vol. 1004 No. 1 Article 1
The shape of the heliosphere, regarded as comet-like since the 1960s, has recently been the subject of intense debate in the last decade. There is disagreement as to whether the heliospheric tail extends to ∼10,000 au in a comet-like shape or if it is short (∼400 au) with a split. Energetic neutral atom (ENA) maps from ...
Added: June 3, 2026
Kartsev A., Nishant T., Saswata G. et al., Journal of Materials Chemistry C 2026 Article -
Overheating remains a critical limitation in high-performance electronic and computing systems,
necessitating the development of efficient thermal management fluids. In this work, a magnetically
responsive hybrid ferrofluid was developed by incorporating two-dimensional hexagonal boron nitride
(2D-hBN) nanosheets into a Mn–Zn–ferrite-based ferrofluid. The hybrid system retains magnetic
responsiveness while leveraging the high in-plane thermal conductivity and chemical stability of 2D-hBN
nanosheets. ...
Added: June 2, 2026
Fortuna A. S., A.I. Kartsev, Gorshenkov M. V. et al., Journal of Alloys and Compounds 2026 Vol. 1070 Article 188711
The τ-phase in Mn-Al-Ga alloys is a promising candidate for rare-earth-free permanent magnets. This study re-veals that the τ(γ₂)-phase in rapidly quenched Mn55Al36Ga9 ribbons contains a high density of dislocations, which
form antiphase boundaries (APBs). Using transmission electron microscopy and density functional theory, we
demonstrate that Mn atoms at these APBs couple antiferromagnetically. This antiferromagnetic interaction is
identified ...
Added: June 2, 2026
Gnetov F., Konakov V., Успехи математических наук 2026 Т. 81 № 3 (489) С. 161–162
Пусть M обозначает симметрическое пространство некомпактного типа ранга 1. Опираясь на фундаментальную работу [1], в [2] было показано, что плотность соответствующим образом нормированной суммы независимых Hn-значных случайных величин, определенная через сложение Мёбиуса в модели шара Пуанкаре, сходится к фундаментальному решению соответствующего уравнения теплопроводности. Пределом являлся нормальный закон на Hn, соответствующий ядру теплопроводности, определяемому оператором Лапласа–Бельтрами. ...
Added: June 2, 2026
Dikhtievskaya K., Argunov E., Kartsev A. et al., The Journal of Physical Chemistry Letters 2026 Vol. 17 No. 17 P. 4999–5004
In this study we revealed the effect of scandium doping on the electronic and superconducting properties of the MgB2 compound. Calculations demonstrate that Sc substitutes for Mg atoms, acting as an electron donor. Mg substitution diminishes the density of states in the σ-band and attenuates the electron–phonon coupling, thereby elucidating the reduction in critical temperature. Simultaneously, ...
Added: June 2, 2026
Duran E. ., Pulgar A., Izquierdo R. et al., Physica Status Solidi (A) Applications and Materials 2026 Vol. 223 No. 7 Article e202500942
Ceramic superconductors exhibit remarkable properties, including zero electrical resistance and potent magnetic behavior, operating at temperatures as high as the boiling points of liquid nitrogen (77 K) and liquid hydrogen (20 K). These characteristics position them as key enablers for sustainable technologies spanning electric propulsion, lossless energy transmission, advanced medical imaging, and quantum computation. This review presents ...
Added: June 1, 2026
Borisov V., Danilov V., Электросвязь 2025 № 12 С. 73–84
Представлены результаты математического моделирования процесса полевой эмиссии из катода малых размеров – одного из основных физических процессов, обеспечивающих работы многих электронных устройств, в частности FED-дисплеев (устройства, работающие на принципе полевой эмиссии), кантилеверов и т.д. Дается краткий обзор текущих результатов в области исследования, обосновывается актуальность задачи, приводятся примеры наиболее вероятного использования результатов решения задачи. Обсуждаются физические ...
Added: May 29, 2026
Kuznetsov S. A., Pechen A. N., Lobachevskii Journal of Mathematics 2023 Vol. 44 P. 2101–2108
A three-level Λ-atom (resp., V-atom) is a three-level quantum system with a forbidden direct transition between the two lowest (resp., highest) energy states. These systems are particular examples of three-level systems with only two allowed transitions and are important in quantum optics, e.g., for modeling electromagnetically induced transparency, etc. For generality, we consider not only Λ- ...
Added: October 7, 2025
Lokutsievskiy L. V., Pechen A. N., Zelikin M. I., Journal of Physics A: Mathematical and Theoretical 2024 Vol. 57 No. 27 Article 275302
Finding minimal time and establishing the structure of the corresponding optimal controls which can transfer a given initial state of a quantum system into a given target state is a key problem of quantum control. In this work, this problem is solved for a basic component of various quantum technology processes—a qubit interacting with the ...
Added: November 25, 2024
Vassili N. Kolokoltsov, The Annals of Applied Probability 2022 Vol. 32 No. 3 P. 2254–2288
n this paper we are merging the two new branches of game theory: quantum games and mean-field games (MFG). Building a quantum analog of MFGs requires the full reconstruction of its foundations and methodology, because in N-particle quantum evolution particles are not separated in individual dynamics and the key concept of the classical MFG theory, the ...
Added: October 31, 2022
Kolokoltsov V., Working papers by Cornell University. Series cond-mat.soft "arxiv.org" ( 2020 P. 552–573
Quantum games represent the really 21st century branch of game theory, tightly linked to the modern development of quantum computing and quantum technologies. The main accent in these developments so far was made on stationary or repeated games. In this paper we aim at initiating the truly dynamic theory with strategies chosen by players in ...
Added: October 31, 2022
V. N. Kolokoltsov, Theoretical and Mathematical Physics 2021 Vol. 208 No. 1 P. 937–957
© 2021, Pleiades Publishing, Ltd.Abstract: There is an extensive literature on the dynamic law of large numbers for systems of quantum particles, that is, on the derivation of an equation describing the limiting individual behavior of particles in a large ensemble of identical interacting particles. The resulting equations are generally referred to as nonlinear Schrödinger ...
Added: October 30, 2022
Вожаков В. А., Бастракова М. В., Кленов Н. В. et al., Успехи физических наук 2022 Т. 192 № 5 С. 457–476
The review highlights recent advances in the development of superconducting qubits and quantum circuits designed for a new generation of quantum processors. It primarily focuses on the analysis of control methods for multi-qubit systems — multi-particle quantum systems with configurable, including in situ, parameters of individual elements, and connections between them. It is shown how ...
Added: June 15, 2022
Shapiro D. S., Rubtsov A. N., Remizov S. V. et al., Physical Review A: Atomic, Molecular, and Optical physics 2019 Vol. 99 No. 6 Article 063821
The analysis of single-mode photon fluctuations and their counting statistics at the superradiant phase transition is presented. The study concerns the equilibrium Dicke model in a regime where the Rabi frequency, related to a coupling of the photon mode with a finite-number qubit environment, plays the role of the transition's control parameter. We use the ...
Added: October 29, 2021
Akulin, Journal of Physics B: Atomic, Molecular and Optical Physics 2018 Vol. 51 No. 2 P. 02LT01
A possibility of performing the C-NOT gate operation at the ground and the first excited states of two harmonic oscillators interacting via a two-level system subject to complete control is demonstrated. The system resembles Turing machine, where the result of interaction between oscillators and the two level system is restricted to a certain fixed unitary ...
Added: November 1, 2020
Kryzhevich S., Eugene Stepanov, Journal of Differential Equations 2019 Vol. 267 No. 6 P. 3442–3474
In a recent paper by D. Burago, S. Ivanov and A. Novikov, "A survival guide for feeble fish", it has been shown that a fish with limited velocity capabilities can reach any point in the (possibly unbounded) ocean provided that the fluid velocity field is incompressible, bounded and has vanishing mean drift. This brilliant result ...
Added: October 8, 2019
Sheldon K. M., Titova L., The Journal of Positive Psychology 2019 Vol. 14 No. 5 P. 549–562
Much research has shown that how people explain events affects subjective well-being (SWB), in particular when they explain positive events as being due to internal, stable, and global factors, and negative events as being due to external, unstable, and local factors. In the current research, we asked: how do people explain their SWB itself, and ...
Added: August 28, 2019
Steklov Mathematical Institute, 2017.
Added: June 3, 2017