


Vol 118, No 3-4 (8) (2023)
Articles
Sizes of the Neutron–Proton Halo in Nucleon-Stable States of the 6Li Nucleus
Abstract
The matter, neutron, and proton radii of nucleon-stable 1+ and 0+ states of the 6Li nucleus are studied theoretically within the no-core shell model. The results have been comparatively analyzed with the radii of the 0+ state of the 6He nucleus. To increase the accuracy of calculations, we have developed an extrapolation procedure. A new definition of the quantitative measure has been proposed and justified to describe the properties of a halo formed by loosely bound neutrons and protons in the A-nucleon problem. The sizes of the halo in the indicated states of 6Li have been calculated for the first time. It has been demonstrated that the sizes of their halos are close to those of the two-neutron halo in 6He. Thus, additional reliable evidence of the existence of the neutron–proton halo in the discussed states of 6Li has been obtained.



Search for 8.4-keV Solar Axions Emitted in the M1 Transition in 169Tm Nuclei
Abstract
Axions with an energy of 8.4 keV emitted in the М1 transition in 169Tm nuclei in the Sun are sought in the



Effect of Meteorological Parameters on the Cosmic Muon Flux Studied Using the Effective Generation Level Method with the DANSS Detector Data
Abstract
The DANSS detector is located directly under the nuclear reactor at the Kalinin nuclear power plant. Such a position ensures about 50 m.w.e. shielding from cosmic rays in the vertical direction; as a result, the detector occupies an intermediate position between surface and underground detectors in the shielding from cosmic rays. The sensitive volume of the detector consisting of a 1-m3 plastic scintillator is surrounded by the multilayer passive shielding and muon veto. The main aim of the DANSS experiment is to measure the antineutrino spectrum at various distances from the source. To this end, the detector is placed on a lifting platform in order to record data at three positions of 10.9, 11.9, and 12.9 m from the reactor core. The detector can reconstruct muon tracks passing through its sensitive volume. The pressure, temperature, and decay coefficients for muons in various regions of the zenith angle



Neutral Bremsstrahlung Electroluminescence in Noble Liquids Revisited
Abstract
Recent discovery of neutral bremsstrahlung (NBrS) mechanism of electroluminescence (EL) in noble gases in two-phase detectors for dark matter searches has led to a prediction that NBrS EL should be present in noble liquids as well. A rigorous theory of NBrS EL in noble liquids was developed accordingly in the framework of Cohen–Leckner and Atrazhev formalism. It has been recently followed by the first experimental observation of NBrS EL in liquid argon, which however deviates significantly from the previous theory. Given these results, we revise previous theoretical calculations of EL NBrS in noble liquids to be consistent with experiment. In particular, NBrS EL yield and spectra were calculated in this work for argon, krypton, and xenon with momentum-transfer cross section for electron scattering (instead of energy-transfer one) being used for calculation of NBrS cross section. The results for light noble liquids, helium and neon, are also reexamined.



Rivulet of a Non-Newtonian Fluid Draining on an Inclined Superhydrophobic Surface
Abstract
A rivulet of a power-law-rheology fluid steadily draining from a point source on an inclined superhydrophobic plane is considered. An equation for the shape of the cross section of the rivulet has been derived in the thin layer approximation with the inhomogeneous slip boundary condition (slip coefficients are power functions of the spatial coordinates). Under the assumption that the rivulet is symmetric with respect to its middle plane, the conditions for the existence of a class of self-similar solutions of one ordinary differential equation of the second order have been determined. For some slip parameters of the superhydrophobic surface and some rheological indices of the draining fluid, analytical and numerical solutions from the found class have been constructed and the shape of the cross section of the rivulet and the geometry of the wetting spot have been analyzed.



General Thermodynamic Approach to Describe the Kinetics of Thermal Effects in High-Entropy Metallic Glasses
Abstract
A method is proposed to calculate thermal effects induced by the heat treatment of high-entropy metallic glasses within the general thermodynamic approach. The experimental verification of the proposed method shows that the exothermic effect observed below the calorimetric glass transition temperature, the endothermic effect in the glass transition region, and the exothermic effect during the crystallization of a metallic glass can be quantitatively described using the general thermodynamic equation for the change in the entropy of the glass including the diaelastic effect.



Spin States of Cobalt Ions in the Bulk and on the Surface of LaCoO3 Probed by X-ray Absorption, Emission, and Photoelectron Spectra
Abstract
We present X-ray photoelectron, Co



Unique Structural Features of NbS3 Ribbon Whiskers
Abstract
The X-ray diffraction analysis of NbS3 ribbon whiskers has revealed three structural features: (i) a fine-crystalline structure throughout the entire volume with the preferred orientation along the [001] direction perpendicular to the long b axis of the whisker, (ii) the combination of crystalline macroblocks with a length up to 0.5 mm with small crystallites of various orientations, and (iii) the combination of crystalline macroblocks with the left-hand twisting of planes around the b axis with a pitch angle of 1.25° per every 0.2 mm and with the return to the initial orientation in the next block. Structural features (ii) and (iii) of NbS3 whiskers have not yet been observed, and inorganic crystals with such properties are absent to the best of our knowledge. All crystallites have a unit cell with almost right angles and approximately the same lattice constant c (18.130 Å), whereas the lattice constants a and b are noticeably different in a single sample. All crystallites can be referred to phase IV rather than to phase I, as expected. The right angle between the a and c axes can be explained by the twinning of phase I along the c axis. Differences in the lattice constants in macroblocks indicate large stresses in structures. Such stresses near twins (and/or stacking faults) can significantly affect the free electron density and play a key role in the formation of charge density waves in various phases of NbS3.



Generation of Giant Magnetic Fields in a Hollow Mesoscale Sphere
Abstract
The superresonance effect for a hollow dielectric sphere is numerically simulated with the Mie theory. It is shown for the first time that weakly dissipative mesoscale spheres with an air-filled cavity exhibit a high-order Fano resonance related to internal Mie modes. Superresonance in a hollow sphere is achieved by the accurate choice of the cavity radius, while for a monolithic dielectric sphere, it is ensured by the accurate choice of the outer diameter of the particle under study. In this case, the relative intensities of the resonance peaks in the optical range for both magnetic and electric fields near the sphere poles can have enormous values of 106−107, if the magnetic field magnitude exceeds that of the electric field by a factor larger than 15 for the hollow sphere with a Mie size parameter about 40.



Intrachain Distances in a Crumpled Polymer with Random Loops
Abstract
Crumpled polymer further folded into random loops has been proposed as a minimal model of chromosome organization. How do loops affect spatial distances in such a polymer? Here we investigate the statistics of intrachain distances,






Optimization of Adiabatic Superconducting Logic Cells by Using π Josephson Junctions
Abstract
Adiabatic superconducting logic circuits can ensure the practical implementation of operations with the energy dissipation below the Landauer limit. However, applications of the existing solutions are limited because of two contradictory requirements of a high energy efficiency and a sufficiently fast response of devices. Josephson junctions with a negative critical current (π junctions) allow one to obtain a certain form of the potential energy of superconducting circuits and, as a result, a practically required degree of control of dynamic processes in the proposed reversible logic cells. The features of the current transport and balance of Josephson phases in circuits with π junctions make it possible to improve the coupling between the parts of a reversible computer by a factor more than 2. At the same time, the continuous evolution of the state is ensured at higher critical currents and higher characteristic voltages of the main Josephson junctions of adiabatic superconducting logic cells, which allows an increase in the response rate.



π0, η, η' → γγ Decays and the Explicit Chiral Symmetry Breaking
Abstract
Corrections to the Wess–Zumino–Witten anomaly caused by the explicit breaking of the



Probability of High Intensities of the Light Wave Propagating in a Turbulent Atmosphere
Abstract
We examine statistics of fluctuations of the laser beam intensity at its propagating in turbulent atmosphere. We are interested in relatively large propagating distances and the remote tail of the probability density function. The tail is determined by the stretched exponent, we find its index.



Manifestation of “Slow” Light in the Photocurrent Spectra of Ge/Si Quantum Dot Layers Combined with a Photonic Crystal
Abstract
The spectral characteristics of the photocurrent in the near-infrared range in vertical Ge/Si p–i–n photodiodes with Ge quantum dots embedded in a two-dimensional photonic crystal are investigated. The interaction of the quantum dots with photonic Bloch modes leads to the resonant enhancement of the sensitivity of photodiodes. The dependences of the photocurrent on the angle of incidence of light are used to determine the dispersion relations of the Bloch modes. Regions in the dispersion characteristics where the group velocity of photons is close to zero are revealed. It is established that the maximum enhancement of the photocurrent relative to a photodiode without photonic crystal, which can be up to a factor of ~60, results from the interaction of quantum dots with “slow” Bloch modes.



Giant Raman Scattering on Plasmon Metal Surfaces as a Method to Control Their Functional and Supramolecular Structural Characteristics
Abstract
Fundamentals of surface-enhanced Raman spectroscopy/scattering have been developed and possibility of its application to analyze some structural characteristics of surfaces and agglomerates of plasmonic metal nanostructures has been considered. A remote nondestructive express method based on surface-enhanced Raman spectroscopy has been presented to control the degree of local cracking of a metal coating and the effect of defects/cracks on the conductivity of a thin metallized film (uniaxially stretched polyethylene terephthalate track-etched membrane with a 50-nm silver coating).



Absorption of Microwaves During Plasma Heating at the Second Harmonic of Electron Cyclotron Resonance in Tokamaks and Stellarators: Linear Theory and Experiment
Abstract
We study the microwave absorption during electron cyclotron resonance heating (ECRH) by the extraordinary wave at second harmonic (X2 mode) in the T-10 tokamak and TJ-II stellarator in a wide range of plasma densities, and compare experiments with the classical formulas for the absorption of the injected ECR power. Empirical relations for the absorption efficiency and for the critical plasma density



Effect of “Refraction” of Magnetic Domain Boundaries at Electrical Inhomogeneities
Abstract
A magnetoelectric effect, which manifests itself as a “refraction” of domain walls at the location of an electrode deposited on the surface of an iron garnet film, is studied. The “refractive index” depends on the electric voltage applied to the electrode and varies from 0.6 to 1.2. An electrically induced change in the surface energy of a domain wall due to an inhomogeneous magnetoelectric coupling is suggested as the mechanism of this effect.



Influence of Electron Confinement Effects on the Band Gap of Almost Monatomic EuS2 Layers
Abstract
Europium disulfide is a layered semiconductor with a quasi-ionic bond type. Previously, it has been demonstrated that almost monatomic films can be formed from this material by mechanical splitting. In this work, the most energetically favorable structure of monatomic films is established using ab initio calculations, and the behavior of the band gap depending on the number of monolayers in the film is studied. To establish the role of nonlocal corrections and corrections associated with the spin–orbit interaction, the calculation results are compared with the position of the direct fundamental absorption edge of bulk crystals estimated from the experimental hot photoluminescence and microreflection spectra. It is found that the indirect character of the band gap is also retained in thin films. The confinement effects (dimensional localization of electrons) cause inhomogeneous broadening of the band gap over the Brillouin zone. The gap width almost does not change between the bulk material and its films at the edges of the Brillouin zone, and a significant change occurs only in the center of the Brillouin zone. A singularity in the density of states caused by the equalization of the energies for the D and E0 points of the Brillouin zone is predicted in EuS2 films about 10 ML thick.



High Harmonic Generation near the Low-Frequency Edge of a Plateau under Nonlinear Propagation of 1.24-μm Near-Infrared Femtosecond Laser Radiation in a Dense Argon Jet
Abstract
High (15–25) harmonic generation in the vacuum ultraviolet spectral range (83–50 nm) has been realized by focused (NA = 0.033) near-infrared femtosecond laser radiation (wavelength λ = 1.24 μm) with a vacuum intensity of ~7.5 × 1014 W/cm2 irradiating a dense gas jet. It has been shown experimentally that the use of such a high-numerical aperture focusing requires high (up to 10 bar) gas jet pressures to optimize phase matching. The use of the dense gas jet results in a noticeable manifestation of nonlinear propagation effects for generating radiation, which affect the generation process through the change in the phase matching conditions. Furthermore, it has been shown that the prechirping of the generating pulse makes it possible to compensate a chirp appearing due to self-phase modulation and to increase the harmonic generation efficiency because of the nonlinear compression of the generating pulse. This approach has allowed 17th (73 nm) harmonic generation with an energy of 2 pJ in a pulse and a generation efficiency of 5.4 × 10–9. The estimates obtained have shown that this radiation can be used for single-pulse maskless photolithography in the extreme ultraviolet range.






Second Harmonic Generation as a Noninvasive Method to Study Molecular Processes on the Surface of Lipid Membranes (Brief Review)
Abstract
The development and implementation of modern experimental methods in interdisciplinary projects promote the solution of fundamental problems in molecular biology and medicine. One of these problems is the understanding of the physics of molecular interactions in a narrow (<1 nm) surface layer of cellular lipid membranes (hydration layer of the membrane), where most of the important electrochemical interactions with ions and proteins, transmembrane transport of molecules, and endocytosis occur. The solution of this problem requires noninvasive methods sensitive to changes in the molecular structure of the surface layer of membranes. The aims of this work are to describe advantages of nonlinear optical microscopy and spectroscopy for the study of structural and electrostatic features of lipid membranes, to present the developed method for the visualization of the hydration of lipid membranes, and to discuss the limits of applicability of this method.



On the Electric Area of an Electromagnetic Pulse
Abstract
The propagation of ultrashort electromagnetic pulses with a nonzero electric area in plasma media is analyzed. An equation for the area of an electromagnetic pulse in the one-dimensional geometry has been derived in the unidirectional propagation approximation. It has been shown that this area is not an invariant of motion and can both decrease and increase during the propagation of the pulse depending on the properties of a plasma medium.



Quasiclassical Quantization of the Motion of a Particle in the Presence of a Drag Force Proportional to the Square of the Velocity
Abstract
The quasiclassical one-dimensional motion of a particle in a medium, where the drag force is proportional to the square of the particle velocity, is considered using the Caldirola–Kanai approach. The coherent state of the particle in the presence of a constant conservative force in addition to the drag force is studied. It has been shown that the wave packet undergoes quantum extension to a certain limit, forming a steady propagating profile. Thus, the drag force suppresses the quantum properties of the particle, and the classical features become more pronounced in its motion with time. This property allows one to consider such a medium as a classical instrument continuously measuring the state of the particle. For this reason, the restriction of the spatial extension of the wavefunction can be interpreted as one of the manifestations of the quantum Zeno effect.


