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On a higher integral invariant for closed magnetic lines, revisited
Journal of Geometry and Physics. 2021. No. 170. Article 104379.
Akhmet’ev P.
We recall a definition of an asymptotic invariant of classical link, which is called M-invariant. M-invariant is a special Massey integral, this integral has an ergodic form and is generalized for magnetic fields with open magnetic lines in a bounded 3D-domain. We present a proof that this integral is well defined. A combinatorial formula for M-invariant using the Conway polynomial is presented. The M-invariant is a higher invariant, it is not a function of pairwise linking numbers of closed magnetic lines. We discuss applications of M-invariant for MHD.
Budkov Y., Kiselev M. G., Journal of Chemical Physics 2026 Vol. 165 No. 12 Article 124508
We develop a three-mode statistical-mechanical theory for a two-conformer
solute in a near-critical solvent. A compressible lattice model with
vacancies yields the Gaussian free-energy functional for a critical conserved
density, an orthogonal noncritical conserved mode, and the local conformer
fraction. Their couplings follow from packing and cohesive interactions,
rather than being introduced phenomenologically. Kawasaki transport of the
two conserved fields and ...
Added: September 24, 2026
Kryzhanovskaya N., Makhov I., Dragunova A., St. Petersburg Polytechnical University Journal: Physics and Mathematics 2026 Vol. 19 No. 1.1 P. 98–104
The planar microcavity structure was grown using molecular-beam epitaxy.
Single-mode lasing was observed at a wavelength of 960 nm for pillars with a diameter of
15 μm. At 300 K, the lasing threshold was approximately 30 mW. Increasing the pump
power to 2.7 times the threshold power resulted in a mode energy shift of approximately
1 meV. This shift ...
Added: September 23, 2026
Andreeva S., Gavrilov A. A., Dzhikirba K. R. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 Article 134515
We examine plasma excitations with linear dispersion in a system of superconducting electrons in thin
NbN disks. Using frequency-domain terahertz spectroscopy, we study the evolution of plasmons up to critical
temperature Tc. The observed excitations tend to shift to the lower frequencies while temperature is increasing
and the spectral features vanish at T > Tc. We study the ...
Added: September 23, 2026
Образцова А. А., Ivanov K., Moiseev E. et al., Journal of Physics D: Applied Physics 2026 Vol. 59 No. 30 P. 305103
We demonstrate a thermo-optically tunable microlaser based on an InGaAs/GaAs quantum-dot (QD) active region employing a deformed limaçon-shaped cavity. The asymmetric geometry effectively lifts the degeneracy of high-Q whispering-gallery modes, enabling single-mode lasing. A side-mode suppression ratio exceeds 25 dB over a wide current range. Under continuous-wave electrical pumping, the device achieves a peak output power ...
Added: September 23, 2026
Budkov Y., Journal of Chemical Physics 2026 Vol. 165 No. 12 Article 124105
Exact theories of electrolyte structure must satisfy the nonlocal constraints imposed by electrostatic screening, yet these constraints are most commonly formulated only for homogeneous bulk systems and at the level of two-point correlations. Here, we develop a unified field-theoretic framework that extends them to general inhomogeneous ionic fluids and nonlinear charge correlations. Using a standard ...
Added: September 22, 2026
Боровицкая И. В., Пименов В. Н., Коршунов С. Н. et al., Перспективные материалы 2026 № 10 С. 37–54
Проведено сравнение, обобщение и систематизация механизмов эрозии и разрушения
поверхности малоактивируемых материалов, перспективных для использования в
качестве материалов вакуумной камеры термоядерных реакторов: ванадия, его сплава
V – 10 Ti – 6 Cr – 0,05 Zr – 0,1 Si и вольфрама при последовательном воздействии на
них ионных и тепловых потоков. Тепловые потоки имитировали с помощью мощного
импульсного лазерного излучения (ЛИ), создаваемого ...
Added: September 22, 2026
Iontsev M.A., Mukhin S. I., Fistul M. V., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 94 No. 17 P. 174–510
We report a theoretical study of the ac response of superconducting quantum metamaterials (SQMs), i.e., an array of qubits (two-level systems) embedded in a low-dissipative resonator. By making use of a particular example of a SQM, namely the array of charge qubits capacitively coupled to the resonator, we obtain a second-order phase transition between an ...
Added: September 22, 2026
Shilov A. L., Elesin L., Kravtsov M. et al., Nature Communications 2026 Vol. 17 No. 1 Article 9734
Identifying the microscopic processes limiting conductivity is essential for understanding correlated quantum materials. In twisted bilayer graphene, metallic resistivity follows ρ ~ Tα with widely varying α, fueling competing interpretations from phonon-limited transport and umklapp scattering to strange metallicity and heavy-fermion renormalization. Here, we use terahertz excitation to selectively heat electrons while keeping the lattice cold, separating ...
Added: September 20, 2026
Ibrahim A., Derkach D., Kaledin M. et al., Computer Physics Communications 2026 Vol. 329 Article 110407
We present RLABC (Reinforcement Learning for Accelerator Beamline Control), an open-source Python framework that automatically transforms standard Elegant beamline configurations into reinforcement learning environments. RLABC integrates with the widely-used Elegant beam dynamics simulation code via SDDS-based interfaces, enabling researchers to apply modern RL algorithms to beamline optimization with minimal RL-specific development. Validation on a test ...
Added: September 20, 2026
Копьев А., JETP Letters 2026 Vol. 123 No. 5 P. 310–316
The incompressible three-dimensional Euler equations develop very thin pancake-like regions of exponen tially increasing vorticity. The characteristic thickness of such regions decreases exponentially with time, while the other two dimensions do not change considerably, making the flow near each pancake strongly anisotropic. The pancakes emerge in increasing number with time, which may enhance the anisotropy ...
Added: September 18, 2026
Захаров А. В., Düven H., Capar M. I., Physics Letters A 2026 No. 576 Article 131388
Molecular dynamics simulations were carried out to study the structural properties of nematic pentyl
cyanobiphenyl (5CB) and pentyloxy cyanobiphenyl (5OCB) liquid crystals (LCs) doped with gold nanoparti
cles (GNPs) of different numbers, shapes and sizes. The spherical GNPs of two different radii and rod-like have
been doped in 5CB and 5OCB cyanobiphenyl liquid crystals. In order to describe ...
Added: September 17, 2026
Andreev D. V., Kornev S. A., Bondarenko G.G. et al., Inorganic Materials: Applied Research 2026 Vol. 17 No. 5 P. 1226–1230
Comparative studies are carried out to investigate high-field charge degradation effects in the gate
dielectric of metal—insulator—semiconductor (MIS) structures with aluminum and polysilicon gates.
Charging phenomena in MIS structures are explored using high-field electron injection into the dielectric
under conditions of gradually increasing voltage current density, with periodic short-term switching to a measurement
mode at a constant low injection ...
Added: September 15, 2026
Poddiakov A., / Series Social Science Research Network "Social Science Research Network". 2026. No. 7437658.
Clarity of knowledge and reasoning is necessary in many cases. Yet vagueness in scientific thinking related to surprise, curiosity, "ability to engage with not-knowing" (de Freitas) and abductive reasoning is also a crucially important source of scientific creativity which supplements combinatorial logic when dealing with the already known. Starting from studies by C. S. Peirce ...
Added: September 15, 2026
Water confined in heterogeneous clay–quartz pores: Structure and dynamics from atomistic simulations
Glushak A., Tararushkin E., Smirnov G., Colloids and Surfaces A: Physicochemical and Engineering Aspects 2027 Vol. 752 Article 141756
The molecular-scale behavior of water in heterogeneous clay–quartz systems is critical for understanding cementation processes in natural soils and compacted bentonite, which is crucial for oil recovery and nuclear waste disposal barriers construction. Here we investigate how heterogeneity of mixed Na-montmorillonite and α-quartz surfaces affect water structure and dynamics in nanopores of 2.5 to 60 Å ...
Added: September 15, 2026
Bochkin G., Doronin S., Fel’dman E. et al., Lobachevskii Journal of Mathematics 2024 Vol. 45 No. 3 P. 1188–1207
We consider the remote state restoring and perfect transfer of the zero-order coherence matrix (PTZ) in a spin system governed by the XXZ-Hamiltonian conserving the excitation number. The restoring tool is represented by several nonzero Larmor frequencies in the Hamiltonian. To simplify the analysis we use two approximating models including either step-wise or pulse-type time-dependence ...
Added: September 14, 2026
P. M. Akhmet'ev, Dvornikov M. S., Journal of Geometry and Physics 2024 Vol. 198 Article 105102
We construct a new Yang-Mills 3D-solution on the space of negative scalar curvature. We
discuss a problem of non-abelian gauge symmetry is broken with the assumption that
a scalar curvature of the domain is a negative small parameter. In this case we use the
following fact: a geometrical scale related with Vassiliev’s discriminant of magnetic lines
coincides with a ...
Added: January 23, 2024
Akhmet’ev P., Journal of Geometry and Physics 2022 No. 178 Article 104583
It is well known that the magnetic helicity is not a single invariant in ideal magnetohydrodynamics. We study the problem of whether the exponent -1.7 of the slope of the turbulent spectrum of magnetic energy can be explained. An affirmative answer is obtained. The answer is based on the use of the M-invariant (numerical measure ...
Added: July 8, 2022
Екомасов Е. Г., Степанов С. В., Назаров В. Н. et al., Письма в Журнал технической физики 2021 Т. 47 № 17 С. 26–28
The joint effect of a spin-polarized current and an external magnetic field on the magnetization
dynamics in vortex spin-transfer nano-oscillators 400 nm in diameter has been investigated. The coupled
dynamics of magnetic vortices has been calculated numerically using the SpinPM software package for
micromagnetic simulation. The dependence of the frequency of stationary coupled vortex oscillations on the
magnetic field, ...
Added: March 26, 2022
Akhmet’ev P., Труды Математического института им. В.А. Стеклова РАН 2020 Т. 308 С. 50–64
Вычисляется среднее значение асимптотического инварианта заузленной траектории геодезического потока Гиса–Деорнуа. Результат важен для исследования магнитостатического положения равновесия магнитного поля в жидкой проводящей среде ...
Added: February 28, 2021
Akhmet’ev P., Теоретическая и математическая физика (Российская Федерация) 2020 Т. 204 № 1 С. 130–141
Уравнение среднего магнитного поля описывает процесс генерации магнитного поля на большом масштабе за счет ЭДС, возникающей на мелком масштабе. Рассматривается случай, когда магнитное поле на большом масштабе также случайно. Определяется функция плотности магнитной спиральности, которая инвариантна при калибровочном преобразовании магнитного вектор-потенциала. Изучается уравнение для потока магнитной спиральности крупномасштабного поля. Вводится поправочное слагаемое, связанное с инвариантом квадратичной ...
Added: February 28, 2021
Yushkov E. V., Lukin A., Sokoloff D. D., Journal of Experimental and Theoretical Physics 2020 Vol. 130 No. 6 P. 935–944
We compare the classical mean-field dynamo model proposed by Steenbeck, Krause, and Rädler to describe the generation of large-scale magnetic fields and the Kazantsev model that describes the small-scale dynamo in an unbounded homogeneous and isotropic flow. We consider the subcritical regime of small magnetic Reynolds numbers whereby there is no rapid generation. The same ...
Added: December 2, 2020
Akhmet’ev P., Vyugin I. V., Arnold Mathematical Journal 2020 Vol. 6 No. 2 P. 199–211
The main result of the paper is the formula that calculates the dispersion of the asymptotic Hopf invariant of a magnetic field. The paper contain examples, which describe magnetic fields in a conductive medium. ...
Added: September 12, 2020
Yushkov E. V., Lukin A. S., Geophysical and Astrophysical Fluid Dynamics 2017 Vol. 111 No. 6 P. 527–541
Using a magnetic dynamo model, suggested by Kazantsev (J. Exp. Theor. Phys. 1968, vol. 26, p. 1031), we study the small-scale helicity generation in a turbulent electrically conducting fluid. We obtain the asymptotic dependencies of dynamo growth rate and magnetic correlation functions on magnetic Reynolds numbers. Special attention is devoted to the comparison of a longitudinal ...
Added: January 31, 2020