Issue 5, 2025
Algebraic resonance perturbation theory in problems of nonlinear and quantum optics
Algebraic resonance perturbation theory in problems of nonlinear and quantum optics
A. M. Basharov
The algebraic resonance perturbation theory (ARPT) is formulated, general formulas of the theory are written out, with the help of which effective Hamiltonians are concisely derived, interference interactions are described, kinetic equations for various cases of interaction of electromagnetic radiation with quantum systems are obtained. It is pointed out that the method of stochastic differential equations is naturally integrated into ARPT and that the principles of selecting ARPT terms are physically justified in the case of an approximation of the environment of an open system by delta-correlated noise. The inevitability of the appearance of interference interactions is emphasized due to the formulated ARPT requirements regarding the selection of only slowly time-varying terms in the Dirac picture into an effective Hamiltonian.
Show AbstractSome physical factors in the development of secondary cancers in patients who have undergone radiation therapy.
Some physical factors in the development of secondary cancers in patients who have undergone radiation therapy.
A. A. Shcherbakov$^{1,2}$, I. V. Khramov$^1$, E. N. Lykova$^{1,2}$, S. A. Gavrilova$^3$, F. R. Studenikin$^{1,2}$, A. P. Chernyaev$^{1,2}$
The review presents methods of assessment and statistical data on the occurrence of secondary malignant neoplasms in patients who have undergone radiation therapy. The influence of factors such as the age and sex of the patient, the location of the primary tumor, and the method of radiation treatment is examined. It has been established that the highest risks of developing secondary cancer are observed in children, women, and with the use of photon radiation therapy. A comparison with experimental data obtained from animals, which revealed similar patterns, is provided. Special attention is given to risk assessment models depending on the radiation dose. The main models used for risk assessment are highlighted. Certain factors that may influence the development of secondary cancer during radiation therapy are identified, including the impact of secondary particles and the use of medical imaging.
Show AbstractHeat capacity at constant pressure on the crystallization and melting line of argon
Heat capacity at constant pressure on the crystallization and melting line of argon
P. N. Nikolaev
In this work, the main characteristics of the crystal-homogeneous phase transition in argon are calculated based on the correlation cell-cluster decomposition. On the crystallization and melting line, the heat capacity at constant pressure was calculated for the crystalline phase and for the homogeneous phase. There is a monotonic decrease in heat capacity at constant pressure with increasing temperature. The theoretical data were compared with experimental data and good agreement was obtained.
Show AbstractThe effect of electromagnetic radiation birefringence in the field of a relativistically rotating pulsar or magnetar within the framework of vacuum nonlinear electrodynamics
The effect of electromagnetic radiation birefringence in the field of a relativistically rotating pulsar or magnetar within the framework of vacuum nonlinear electrodynamics
M. S. Seidaliyeva$^1$, V. I. Denisov$^2$, D. I. Pavlovna$^3$
Within the framework of the parameterized post-Maxwellian vacuum electrodynamics, the propagation of an X-ray or gamma-ray pulse through the electromagnetic field of a relativistically rotating pulsar is studied. Expressions are obtained for the trajectory of this pulse and the law The effect of electromagnetic radiation birefringence in the field of a relativistically rotating pulsar or magnetar within the framework of vacuum nonlinear electrodynamicsof its motion from the point rπ = {π₯π , π¦π , π§π }, where an X-ray or gamma-ray burst occurs at time π‘ = π‘π to the point rπ = {π₯π , π¦π , π§π}, where the detector of this radiation is located. In the case when the post-Maxwellian parameters of the theory differ, π1 ΜΈ= π2, the time of nonlinear electrodynamic delay of electromagnetic signals transported by different normal modes is calculated. The change in the polarization state of the X-ray or gamma-ray pulse after passing through the electromagnetic field of the relativistically rotating pulsar is analyzed. The possibilities of observing the nonlinear effect of the electromagnetic field of a relativistically rotating pulsar on X-ray and gamma pulses have been discussed.
Show AbstractDifferential cross section of the $^{18}$Π(t, p)$^{20}$Π reaction as a test for determining the size of the two-neutron periphery of the $^{20}$Π nucleus
Differential cross section of the $^{18}$Π(t, p)$^{20}$Π reaction as a test for determining the size of the two-neutron periphery of the $^{20}$Π nucleus
L. I. Galanina, N. S. Zelenskaya
The $^{18}$Π(t, p)$^{20}$Π reaction is used to study the neutron periphery of the ground state of the 20O nucleus. The experimental differential cross section of the reaction is consistent with the theoretical one, which is determined taking into account the mechanisms of the deuteron stripping and sequential neutron transfer. The reconstructed wave functions of the deuteron and virtual neutrons relative to the core allow us to calculate the size of the neutron skin layer in the 20O nucleus. The presence of a two-neutron periphery in the $^{20}$O(ground state) nucleus has been confirmed in the form of a relatively extended skin layer in both the deuteron and cigar-shaped configurations
Show AbstractSimulation of the RCS measurements of the conductive disk in the tapered anechoic chamber with lens
Simulation of the RCS measurements of the conductive disk in the tapered anechoic chamber with lens
N. P. Balabukha$^{1,2}$, N. L. Menshikh$^{1,2}$
The simulation of measuring the scattering characteristics of a reference object in the form of a plane disk in a tapered anechoic electromagnetic chamber (TAEC) with a lens is carried out. Two lens collimators are considered: an ordinary hyperbolic lens and the same lens coated on both sides with matching layers for a frequency of 600~MHz. The influence of the non-uniformity of the field distribution in the quiet zone of the chamber on the measurement accuracy of the radar cross section (RCS) of the object is investigated. It is shown that a collimator with a coated lens provides higher measurement accuracy of the RCS of the disk in the side lobes of the scattering pattern due to the provision of less non-uniformity field amplitude distribution in the quiet zone of the chamber. The influence of re-reflection between the lens and the disk on the accuracy of its RCS measurements was also investigated. It is shown that a coated lens reduces the effect of re-reflection not only at the matching frequency but also in enough wide frequency range.
Show AbstractOn modeling acoustic fields in a marine waveguide with refined boundary conditions on the surface and bottom
On modeling acoustic fields in a marine waveguide with refined boundary conditions on the surface and bottom
Yu. I. Papkova$^1$, S. O. Papkov$^2$
The problem of the sound field of a point sound source situated in a non-ideal marine waveguide is considered. The boundaries of the waveguide are assumed to be plane-parallel, there are three layers: a water layer with a non-uniform refractive component of the speed of sound, a layer of liquid sediments, and a bottom elastic layer on a rigid base. The water layer is limited by a homogeneous air half-space. Analytical expressions for impedance functions at the boundaries of the water layer were obtained for the first time for this waveguide model, which makes it possible to construct the Green's function of the vertical boundary value problem. Moreover, exact values for the residues of the Green's function are found, which allow one to write an exact analytical representation for the sound pressure potential as a sum of normal modes. It is shown that the influence of the continuous spectrum (integrals along the branch cuts) is small even at small distances from the source. As the thickness of the elastic layer decreases, the discrete spectrum of the problem tends to the values for a classical waveguide, and at a sufficiently large thickness and attenuation it is similar to the discrete spectrum of the Pekeris elastic waveguide. Examples of numerical implementation for waveguide parameters typical for the Black Sea waters are given.
Show AbstractRegistration of pulsed terahertz radiation by a superconducting bolometer in the process of parametric dowm-conversion
Registration of pulsed terahertz radiation by a superconducting bolometer in the process of parametric dowm-conversion
K. A. Kuznetsov$^2$, N. I. Tatyana$^2$, I. V. Pentin$^3$, G. K. Kitaeva$^{1,2,4}$
The statistical distributions of the output signals of a superconducting bolometer exposed to weak photon pulses with a frequency of 1 THz from a pump with a pulse duration of 30 ps are investigated. Terahertz pulses are obtained by the method of strongly nondegenerate parametric scattering in a LiNbO3 crystal cooled to 4.8 K. Various scenarios of the response of superconducting bolometer to excitation by a small number of terahertz photons are discussed.
Show AbstractDichroism and birefringence in X-ray spectra of forbidden reflections
Dichroism and birefringence in X-ray spectra of forbidden reflections
M. V. Gorbunova$^1$, E. N. Ovchinnikova$^1$, A. P. Oreshko$^1$
The paper implements an approach using a propagation matrix to calculate the intensity of Bragg reflections in resonant X-ray diffraction. This allows one to take into account anisotropic effects that lead to a change in the polarization of radiation during propagation. Using the example of processing the spectra of forbidden reflections in an iron orthoborate crystal, performed using a program based on this approach, an improvement in the results of calculations with experimental data is demonstrated in comparison with standard methods.
Show AbstractSPRING ATMOSPHERIC BLOCKINGS IN THE NORTHERN HEMISPHERE: CHANGES IN RECENT DECADES (1993-2023)
SPRING ATMOSPHERIC BLOCKINGS IN THE NORTHERN HEMISPHERE: CHANGES IN RECENT DECADES (1993-2023)
I. I. Mokhov$^{1,2}$, J. R. Eremin$^1$
This paper presents an analysis of the spring atmospheric blockages (SAB) in the Northern Hemisphere (NH) in 1992-2023. The results of the analysis indicate a significant increase in blocking activity in the atmosphere of the joint venture in recent decades. The noted trend is manifested against the background of a general increase in the near-surface temperature of the NH in the spring seasons. The following SAB parameters were used in the study: quantity, average duration, total duration, intensity, and size. There were obtained estimates of the statistically significant increase in the total duration of the SAB, their number and size with an increase in the average spring near-surface temperature in the NH.
Show AbstractFluorescence of various antropogenic pollutants of hydrosphere when probing of water column by pulsed ultraviolet lidar
Fluorescence of various antropogenic pollutants of hydrosphere when probing of water column by pulsed ultraviolet lidar
L. E. Yakushkin
A criterion has been developed for detecting anthropogenic debris floating on the water surface when probing the water column with a pulsed ultraviolet laser with a wavelength of 355 nm probing radiation. The criterion was applied to lidar sounding data of the near-surface layer of the sea in several expeditions to the Black Sea. The conditions of applicability of the proposed criterion for the detection of marine debris are formulated. The results obtained using this criterion are compared with visual observation data. The possibility of using the criterion to assess the extent of pollution of the World Ocean is shown.
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