?
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.
Fedorov Timofey, Moscow Mathematical Journal 2026 Vol. 26 No. 1 P. 73–85
We obtain a complete list of smooth projective threefolds over C for which the dimension of the space of vanishing cycles (in H2(Y,Q) of the smooth hyperplane section Y) equals 2. We also obtain a complete list of rank 2 very ample vector bundles E on smooth projective surfaces with c2(E)=3. ...
Added: June 25, 2026
Воронеж: Издательский дом ВГУ, 2026.
В сборнике представлены материалы докладов и лекций, включенных в программу весенней математической школы. ...
Added: June 25, 2026
Воронеж: Издательский дом ВГУ, 2026.
В сборнике представлены материалы докладов и лекций,
включенных в программу Воронежской зимней матаматической школы С. Г. Крейна - 2026. ...
Added: June 25, 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
Gadzhimirzaev S., Хельвас А. В., Computer Research and Modeling 2026 Vol. 18 No. 2 P. 423–438
This article presents a model of a fully automated warehouse with deep storage racks designed
for boxed goods storage. The study focuses on optimizing warehouse operations through discrete
multiagent simulation of shuttle movements for pallet loading and unloading tasks. The authors
investigate various product placement strategies, including the Nearest Channel Positioning Algorithm
(NCPA), Most Empty ChannelGroup Placement (MECGP), and ...
Added: June 24, 2026
Gaianov N., Parusnikova A., Уфимский математический журнал 2026 Т. 18 № 2 С. 14–22
We consider an algebraic 𝑞–difference equation. We propose a sufficient condition for the existence of a formal power–logarithmic expansion in the vicinity of zero of the solution to such an equation. We apply this sufficient condition to construct the formal expansion of a solution to a certain 𝑞–difference analogue of the fifth Painlevé equation for
particular ...
Added: June 24, 2026
Buryak A., Clader E., Tessler R., Journal of Differential Geometry 2024 Vol. 128 No. 1 P. 1–75
We conclude the construction of $r$-spin theory in genus zero for Riemann surfaces with boundary. In particular, we define open $r$-spin intersection numbers, and we prove that their generating function is closely related to the wave function of the $r$th Gelfand--Dickey integrable hierarchy. This provides an analogue of Witten's $r$-spin conjecture in the open setting ...
Added: June 23, 2026
Buryak A., Shadrin S., Epijournal de Geometrie Algebrique 2024 Vol. 8
We present a family of conjectural relations in the tautological cohomology of the moduli spaces of stable algebraic curves of genus g with n marked points. A large part of these relations has a surprisingly simple form: the tautological classes involved in the relations are given by stable graphs that are trees and that are decorated only by powers ...
Added: June 23, 2026
Buryak A., Rossi P., Letters in Mathematical Physics 2024 Vol. 114 Article 97
We give explicit formulas for the number of meromorphic differentials on $CP^1$ with two zeros and any number of residueless poles and for the number of meromorphic differentials on $CP^1$ with one zero, two poles with unconstrained residue and any number of residueless poles, in terms of the orders of their zeros and poles. These ...
Added: June 23, 2026
Buryak A., Rossi P., Zvonkine D., Geometry and Topology 2024 Vol. 28 P. 2793–2824
We prove that the cohomology classes of the moduli spaces of residueless meromorphic differentials, ie the closures, in the moduli space of stable curves, of the loci of smooth curves whose marked points are the zeros and poles of prescribed orders of a meromorphic differential with vanishing residues, form a partial cohomological field theory (CohFT) of ...
Added: June 23, 2026
Buryak A., Труды Математического института им. В.А. Стеклова РАН 2024 Т. 325 С. 26–66
The main goal of the paper is to show that the DR hierarchies, introduced by the author in an earlier paper, allow one to establish, in the most clear way, a relation between the topology of the Deligne–Mumford compactification of the moduli space of smooth algebraic curves of genus g with n marked points and integrable systems ...
Added: June 23, 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
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
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
Калужский печатный двор, 2026.
Conference Proceedings INTERNATIONAL CONFERENCE
“Mathematical Ideas of Academician
P.L. Chebyshev, Their Applications in Natural
Sciences and Artificial Intelligence Technologies”
dedicated to the 205th anniversary of his birth ...
Added: June 20, 2026
Джанбекова А. Р., Shvedov A. S., Математическое моделирование 2026 Т. 38 № 3 С. 159–176
Boundary value problems for the Black–Scholes partial differential equation, which describes the value of a financial instrument, may contain a free boundary condition if the financial instrument allows for early exercise. This article considers free boundary value problems for the Black–Scholes equation and the convection diffusion equation. For the convection diffusion equation, a finite difference ...
Added: June 20, 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
Buryak A., Tessler R., Troshkin M., Journal of Geometry and Physics 2026 Vol. 223 Article 105783
We give a natural definition of open Hurwitz numbers, where the weight of each ramified covering includes an integer parameter N taken to the power that is equal to the number of boundary components of a Riemann surface with boundary mapping to . We prove that the resulting sequence of partition functions, depending on , is a tau-sequence of ...
Added: June 19, 2026
Buryak A., Rossi P., Communications in Mathematical Physics 2025 Vol. 406 Article 205
Of the two approaches to integrable systems associated to semisimple cohomological field theories (CohFTs), the one suggested by Dubrovin and Zhang and the more recent one using the geometry of the double ramification (DR) cycle, the second has the advantage of being very explicit. The Poisson operator of the DR hierarchy is , where is the metric ...
Added: June 19, 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