Issue 5, 2023
Vacuum polarization in the cosmic-string background
Vacuum polarization in the cosmic-string background
Yu. V. Grats, P. A. Spirin
Within the framework of one-loop quantum gravity we consider the vacuum polarization effect of the minimally-coupled massive scalar field near the infinitely-thin straight cosmic string. It is shown that the massive-field relative contribution into the renormalized vacuum mean of the energy density becomes negligible at the distance of several Compton lengths.
Show AbstractLyapunov exponent and growth rate for geodesic deviation in Hacobi equation with random curvature
Lyapunov exponent and growth rate for geodesic deviation in Hacobi equation with random curvature
A. E. Mamadova, D. D. Sokoloff
The rate of growth of the geodesic deviation in a homogeneous and isotropic on average cosmological model, which takes into account the fluctuations of curvature is being research. Numerical modeling methods have shown that the rate of growth of the geodetic deviation increases with increasing distance to the celestial body on the geodesic at the same rate as the length of a two-dimensional vector composed of the geodetic deviation and its derivative, the growth rate of which can be calculated theoretically in the so-called Ferstenberg theory.
Show AbstractThe Cauchy Problem for a Singularly Perturbed Delay Equation
The Cauchy Problem for a Singularly Perturbed Delay Equation
N. T. Levashova, N. A. Mikheev
The paper considers the Cauchy problem for a singularly perturbed first-order ordinary differential equation with possibly a non-linear right-hand side that, in addition to the function to be found, also depends on the same function, but taken with a delay in time. The considered problem is singularly perturbed due to the presence of a small parameter in front of the time derivative. Such problems usually have solutions with large gradient in the vicinity of the initial moment of time and in the vicinity of the moment equal to the delay time. The aim of this work is to construct an asymptotic approximation and prove the existence of a smooth solution to the problem.
Show AbstractMultiphoton quantum teleportation
Multiphoton quantum teleportation
A. V. Belinsky, A. P. Grigorieva, I. I. Dzhadan
The possibility of multiphoton teleportation with obtaining clones of entangled particles is proposed. A vulnerability has been discovered in the previously considered physically invulnerable quantum teleportation channel. The issues of Lorentz invariance in the implementation of quantum teleportation are investigated
Show AbstractInfluence of the spatial dispersion in metal on the optical characteristics of the layered magnetoplasmonic nanoparticle cluster
Influence of the spatial dispersion in metal on the optical characteristics of the layered magnetoplasmonic nanoparticle cluster
Yu. A. Eremin$^1$, A. S. Penzar$^2$
In this paper, the diffraction problem of a plane electromagnetic wave on a cluster of two layered nanocylinders consisting of a magnetoplasmonic core and a golden shell is considered. The resulting influence of spatial dispersion in the golden shell is taken into account within the framework of the Generalized Nonlocal Optical Response theory. Based on the scheme of the discrete source method, the influence of the relative position of particles, their deformation and the effect of spatial dispersion on the behavior of the absorption cross section and the near-field gain is analyzed. It is shown that the position of the plasmon resonance can be shifted to the transparency of biological tissues due to variations in the distance between the particles and the core material. It has been established that account for the spatial dispersion in the golden shell leads to a decrease in the intensity and a slight shift in the position of the plasmon resonance in the short-wave region, without taking it beyond the tissue transparency region.
Show AbstractCharacteristics of the dineutron periphery of the nucleus, manifested in the $^{12}$С(t, p)$^{14}$С reaction
Characteristics of the dineutron periphery of the nucleus, manifested in the $^{12}$С(t, p)$^{14}$С reaction
L. I. Galanina$^{1,2}$, N. S. Zelenskaya$^{1,2}$
The $^{12}$С(t, p)$^{14}$С reaction is used to study the neutron periphery of the $^{14}$С(g.s.) nucleus. The experi-mental differential reaction cross section is compared with the theoretical one, taking into account the mechanisms of dineutron stripping and successive neutron transfer. Good agreement between the calculated cross section and the experimental one made it possible to determine the configura-tion of the two-neutron periphery in the ground state of the 4С nucleus. It is shown that the dineu-tron periphery in $^{14}$С is a "skin" on the nucleus surface. The one-neutron cigar-shaped configuration associated with the independent neutron transfer mechanism is quite extended.
Show AbstractHypernuclei and Neutron Stars with Charge Symmetry Breaking Hyperonic Potentials
Hypernuclei and Neutron Stars with Charge Symmetry Breaking Hyperonic Potentials
D. E. Lanskoy$^1$, S. A. Mikheev$^{1,2}$, S. V. Sidorov$^{1,2}$, T. Yu. Tretyakova$^{1,2}$
In this paper, we propose a method of taking charge symmetry breaking (CSB) in hypernuclei and neutron stars into account within the framework of the Hartree-Fock approach with Skyrme interaction. The parameters of the contribution of $\Lambda N$-Skyrme force leading to CSB are derived from the corresponding parameters of the hyperon-nucleon interaction in the meson exchange models. Based on the obtained parameters, the effect of charge symmetry breaking on the hyperon binding energy in carbon hypernuclei is analyzed. The effect of charge symmetry breaking on the characteristics of neutron stars, such as their maximum mass and radii, is considered for the first time.
Show AbstractSeparation of Quark and Gluon Jets in Heavy Ion Collisions at High Energies
Separation of Quark and Gluon Jets in Heavy Ion Collisions at High Energies
S. V. Obraztsov, O. L. Kodolova
The possibility of separation of quark and gluon jets in heavy ion collisions, both in the presence of the effect of quenching of jets and in its absence, was investigated. Using machine learning methods, a method for reconstruction of quark and gluon jet fractions has been developed using variables characterizing the shape, multiplicity, and charge of the jet. The possibility of using these variables to study the characteristics of a dense medium arising from the collision of high energy ions is shown
Show AbstractDispersive element of the compact spectrometer based on photonic crystal with modulated photonic band gap
Dispersive element of the compact spectrometer based on photonic crystal with modulated photonic band gap
N. I. Pyshkov$^1$, S. E. Svyakhovskiy$^2$
A compact dispersive element based on a photonic crystal with a modulated period has been experimentally demonstrated. The position of the photonic band gap of this crystal gradually shifts with depth towards long waves, so different spectral components are reflected from different depths of the structure. At inclined incidence, this provides a significant Goos-Henchen shift and its strong spectral dependence and contributes to the spatial separation of the spectral components.
Show AbstractOn the stability of the dislocation structure of speckle fields
On the stability of the dislocation structure of speckle fields
A. M. Zotov, P. V. Korolenko
The features of propagation in free space of light beams with a dislocation structure of the wave front are considered. The resistance to the influence of diffraction a of small-scale dislocation system providing spatial superresolution is analyzed. Based on a comparison of the characteristics of various types dislocation formations, a conclusion is made about the highest structural stability of systems with screw edge dislocations. Such dislocations can be obtained by azimuthal rotation of edge dislocations, which are characterized by a sharp jump in the phase along a singular line. The results obtained can be used to optimize the characteristics of optical devices with ultrahigh spatial resolution, as well as to develop software for the operation of spatial light modulators that form beams with a given amplitude-phase profile.
Show AbstractMagnetic hysteresis of Sm$_{1-x}$Gd$_x$Co$_3$Cu$_2$ alloys
Magnetic hysteresis of Sm$_{1-x}$Gd$_x$Co$_3$Cu$_2$ alloys
V. E. Sevryukov, O. B. Degteva, A. Yu. Karpenkov, A. I. Ivanova, E. M. Semenova
In work the results of a comprehensive study of hysteresis parameters of Sm$_{1-x}$Gd$_x$Co$_3$Cu$_2$ (x=0.1–0.9) alloys, taking into account the real microstructure presents. It is shown that in the state as-cast, all alloys of this series are significantly heterogeneous and inclusions of up to three phase components contain. The use of high temperature annealing at 1050$^\circ$C for 4 hours the microstructure of the alloys changes. However, the single-phase state was achieved only for alloy samples with x = 0.1. The high-coercivity state of the samples arises due to the regular microstructure by the pinning mechanism. The maximum coercive force of the magnitude 0.94 T was obtained with the composition Sm$_{0.4}$Gd$_{0.6}$Co$_3$Cu$_2$.
Show AbstractPhenomenological models of ferroelastics with a fully symmetric order parameter: classification by the methods of the equivariant catastrophe theory
Phenomenological models of ferroelastics with a fully symmetric order parameter: classification by the methods of the equivariant catastrophe theory
S. V. Pavlov
Phenomenological models of phase transitions in proper and pseudoproper ferroelastics for interacting order parameters, one of which is invariant with respect to all transformations of the crystal symmetry (fully symmetric), are constructed using catastrophe theory methods that take into account the symmetry of a thermodynamic system. The models are classified according to the number of control parameters that depend on external thermodynamic conditions. Phase diagrams of one of models are constructed and theoretical temperature dependences of specific heat are calculated. Comparison of theoretical and experimental data showed a satisfactory qualitative agreement.
Show AbstractStudies of the surface features of palladium-based alloys by atomic force and magnetic force microscopy
Studies of the surface features of palladium-based alloys by atomic force and magnetic force microscopy
O. V. Akimova, T. P. Kaminskaya, V. V. Popov
The surface state of palladium-based alloys, namely Pd-6.0In-0.5Ru and Pd-7.0Y (the elements content is given in wt.%) was studied by magnetic force microscopy (MFM) and atomic force microscopy (AFM). The study was carried out within the framework of the current trend to improve the safety of hydrogen separation and storage. The samples for the study were made of high purity metals by arc alloying. They were subjected to reversible hydrogen alloying in order to find the influence of internal deformation of metal systems on their structure-sensitive properties. Peculiarities of morphology of the samples surface and domain structure were determined in the work. The local magnetic properties and their changes are shown in the work as a result of hydrogen influence.
Show AbstractMOLECULAR MODELING OF GLYPROLINE PRO-GLY AND ITS COMPLEXES
MOLECULAR MODELING OF GLYPROLINE PRO-GLY AND ITS COMPLEXES
L. I. Ismailova, G. A. Akverdieva, S. D. Demukhamedova, N. A. Akhmedov
In the present work, glyproline Pro-Gly and its biologically active complexes with heparin and with the antithrombin-heparin protein complex were studied using molecular modeling methods. This molecule is used as a drug, exhibits immunomodulatory, antiulcer, antidiabetic, antithrombotic and anticoagulant effects. Within the molecular mechanics framework its conformational profiles were studied, the geometry and energy of intra- and interresidual interactions were estimated for the most stable states of the studied dipeptide. A comparative analysis of the extended and folded structures of this molecule optimized by the DFT/B3LYP/6-31+G(d,p) method was carried out, the frontier molecular orbitals were calculated, the surface of the molecular electrostatic potential was studied, the effective charges on the atoms were determined, and the dipole moment and polarizability values were calculated. Subsequent molecular docking revealed that the folded structure of Pro-Gly glyproline showed a higher affinity value for both heparin and the antithrombin-heparin protein complex than the extended one. A model of the pharmacophore of the Pro-Gly molecule for its interaction with a specific receptor was proposed. The obtained data form the basis for the development of effective analogs of glyprolines in complex with heparin, which are more specific with respect to their putative target - antithrombin.
Show AbstractModified method of round Gaussian rings. Application to the two-planetary problem
Modified method of round Gaussian rings. Application to the two-planetary problem
B. P. Kondratyev$^{1,2,3}$, V. S. Kornoukhov$^1$, E. V. Basova$^2$
A scheme of the extended method of round Gaussian rings, designed to study the secular evolution of orbits in systems consisting of a central star and two planets, is presented. The reason for the secular evolution of the nodes and inclinations of the orbits of the planets is their mutual gravitational attraction. The orbits of the planets are modeled by homogeneous round Gauss rings, onto which the masses, sizes and inclinations of the orbits, as well as the orbital angular momenta of the planets are transferred. The method takes into account the fact that, in the general case, the ascending nodes of the orbits may not coincide. The mutual gravitational energy of the rings is presented as a series in powers of small tilt angles including terms up to second order. With the help of this function, a closed system of 4 differential equations is compiled that describes the secular evolution of planetary orbits. The solution of the equations is obtained in the final analytical form, which greatly simplifies the interpretation of the studied motions. The method has been tested on the example of the Sun-Jupiter-Saturn system. For the first time, the new approach is used to study the exoplanetary system Kepler-36. Graphs are constructed for all unknown quantities. It has been established that in the course of evolution the mutual inclination angle of the orbits remains constant, and the librations of the orbits in the inclination angle and in the motion of the nodes occur synchronously.
Show AbstractThe effects of underwater relief on the dynamics of the autumnal thermal bar
The effects of underwater relief on the dynamics of the autumnal thermal bar
B. O. Tsydenov
Results of numerical modeling of effects of underwater slope on the dynamics of the thermal bar circulations during the autumn cooling are presented. Cases of the bottom relief geometry corresponding to the configurations "gentle slope", "stepped profile", "trench" , and "steep slope" are considered. It was found that the flow structure, the time of formation, and the speed of propagation of the thermal bar significantly depend on morphological characteristics of lakebed topography in autumn.
Show AbstractEstimation of frequencies and Q-factors of low-frequency Earth’s toroidal normal modes from strain data
Estimation of frequencies and Q-factors of low-frequency Earth’s toroidal normal modes from strain data
A. E. Olshanskii$^1$, M. P. Vinogradov$^2$, V. K. Milyukov$^2$
Estimations of the parameters of three low-frequency toroidal modes $_0$T$_2$, $_0$T$_3$ and $_0$T$_4$, excited by 13 largest earthquakes of the 21st century, are presented. The estimates were obtained using the data of the Baksan laser interferometer-strainmeter of the SAI MGU. Using the adaptive spectral algorithm, estimates of mode frequencies are obtained and compared with the PREM model. Reliably significant deviations of the $_0$T$_4$ mode frequency estimates for a number of earthquakes are found, and their possible relation to local inhomogeneities in the values of the shear rate and density of the Earth in the upper mantle is shown. The splitting of the $_0$T$_2$ mode due to the ellipticity and rotation of the Earth is studied, and the frequency estimates for the 0T2 singlets excited after significant earthquakes in Sumatra, Japan, and Chile are obtained. The quality factors of low-frequency toroidal modes are estimated by three different ways.
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