The controllability problem for two-dimensional dissipative tunneling in the system of tunnel-coupled quantum dots (a quantum molecule), interacting quantum molecules, and the system “ACM/CTM cantilever tip-quantum dot” simulated by a 2D oscillator potential in a heat bath and an external electric field is investigated. The obtained results qualitatively correspond to the separate experimental volt-ampere characteristics (VACs) for the system “platinized ACM/CTM cantilever tip-gold quantum dot” obtained at Scientific-Research Physical-Technical Institute with Nizhnii Novgorod State University. The previously-predicted 2D tunnel bifurcations with dissipation for the case of interacting particles tunneling in parallel are found to be experimentally observed and stable.
Show AbstractThe statistical characteristics of decaying turbulence are analyzed on the basis of a total system of Navier-Stokes equations. The solution method of Navier-Stokes equations is based on the fundamental solution of a parabolic system, which reduces to integral equations of the Volterra type. A special feature of this method is that difference schemes are not used.
Show AbstractFor the most general renormalizable $N=1$ supersymmetric Yang-Mills theory, regularized by higher derivatives, we investigate a contribution to the Gell-Mann-Low function from the two-loop diagrams, containing cubic interaction of the matter superfields. We find that all integrals with respect to the loop momentum in the massless case are factorized to the integrals of total derivatives and can be easily calculated. Thus, we explain the origin of the relation between the two-loop $\beta$-function and the one-loop anomalous dimension of the matter superfield.
Show AbstractThe aim of this work is to calculate the effective potential in the two-dimensional Gross-Neveu model with violated Lorentz invariance, to study the properties of the obtained potential, and to find extreme points by solving the gap equation and to compare of the results with the theory in the case of nonviolated Lorentz invariance. It is shown that, in the model under study, the effects that make it crucially different from the well-studied model without violation are observed.
Show AbstractA 3-D Gross-Neveu model with Lorentz-violating term $b_\mu$ is studied. The effective potential $V_{\rm eff}$ with a real or imaginary Lorentz-violating term b μ is calculated. The gap equation is obtained and the influence of the presence of an additional term $b_\mu$ on the symmetry of the theory is examined.
Show AbstractA theoretical model of the interaction of two molecules during their mutual grazing is developed. Both molecules in the model are considered to be constructed of identical regular chain-like substructures of diatomic fragments. It is shown that at mutual grazing velocities lower than the Bohr speed in these fragments, which serve as IR radiation antennas, simultaneously with the grazing (${\sim}10^{-12}$ s) both excitation and the accumulation of low-energy collective vibrational states (eximoles) occur. Energy transport occurs from antennas to trap-bonds in the same molecules and the energy exchange between molecules leads to their simultaneous fragmentation. The probability functions of the considered processes are derived and investigated.
Show AbstractEnergy distribution spectra of backscattered electrons in the range 5–25 keV are obtained experimentally. An inverse problem of the reconstruction of the true electron spectrum is solved taking into account the instrument response function of the spectrometer; on the basis of the obtained solution, we specify functions of the real energy distribution of the electrons backscattered from homogeneous and layered samples.
Show AbstractThe influence of a constant magnetic field on the radiation of a planar undulator is studied analytically with the use of generalized Bessel functions. The behavior of on-axis radiation intensity in the undulator and the influence of a magnetic field on off-axis radiation are investigated. The critical magnitude of the constant component of the magnetic field, which has a significant effect on the motion of electrons in the undulator, is calculated analytically. The examples of several planar undulators are discussed, and the influence of the Earth’s magnetic field on their spectrum is evaluated.
Show AbstractMonte Carlo simulation and Mie theory were successfully applied to find the optimum size of titanium dioxide nanoparticles 30–200 nm in diameter suspended in a layer of a transparent medium, which ensure the most efficient attenuation and depolarization of UV radiation in the 288–400 nm wavelength range.
Show AbstractThe luminescent properties of AgLa$_{1-x}$Eu$_x$(MoO$_4$)$_2$ (${x=0.1}, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0$) under laser excitation ($\lambda_{\rm ex}=337.1$ nm) are studied. It is shown that, upon substitution of Eu$^{3+}$ for La$^{3+}$, the symmetry of luminescence centers does not vary. According to the X-ray diffraction data, all samples have scheelite-like structure; the pattern of variation in volumes of their unit cells counts in favor of the presence of a continuous series of solid solutions. It is found that an increase in the europium concentration in AgLa$_{1-x}$Eu$_x$(MoO$_4$)$_2$ leads to an increase in the luminescence intensity with a maximum at ${x=0.9}$.
Show AbstractIn this paper, the dielectric properties of the polar cut of the monocrystal of diglycine nitrate (DGN), depending on the temperature, the frequency of the applied external field and the measuring time, were studied. Using the Havriliak-Negami equation, an approximation of the experimental frequency dependencies of permittivity was made. For each temperature point, a relaxation time spectrum is obtained. The temperature dependence of relaxation time values near the Curie point was found.
Show AbstractIt is established that both the amplitude and temperature dependence of dark conductivity and photoconductivity of preilluminated high-sensitivity layered films of amorphous hydrogenated silicon (a-Si:H) prepared by cyclic deposition with layer-by-layer annealing in hydrogen plasma depend on illumination temperature. The relaxation kinetics of the dark conductivity of these films after illumination is shut off is found to be nonmonotonic. The observed effects can be explained by fast and slow changes in the distribution of energy state density below the midgap during and after illumination.
Show AbstractIt is experimentally demonstrated that the electron energy distribution function (EEDF) and electron density in plasma of a little-studied pulse discharge of a unipolar gas breakdown (UGB) significantly vary in time. The revealed behavior of its plasma parameters is explained based on the proposed physical model of a UGB discharge.
Show AbstractData on muon and electron components of extensive air showers (EAS) (obtained with the EAS MSU array) were used to derive the primary cosmic ray (PCR) mass composition. It is shown that for energies beyond the knee at energy $3\cdot10^{15}$ eV the abundance of heavy nuclei increases with energy. But at energies above $10^{17}$ eV the abundance of light nuclei starts to grow. The primary cosmic ray spectrum in the range 10$^{15}$-10$^{18}$ eV is analyzed. It is shown that at energies above $10^{17}$ eV the additional component appears and it differs from the bulk of Galactic cosmic rays generated by shocks in SN remnants.
Show AbstractThe magnetic field strength above 36 sunspots was studied using the spectra of the HeI λ 1083.030 nm and FeI 1082.837 nm magnetosensitive lines. The value of the field was determined directly by Zeeman splitting of the lines. The advantages of our observations are as follows: (a) in the IR region, the Zeeman splitting exceeds the similar splitting in the visible region by several times, (b) both studied lines are in the same spectrum in close proximity to each other, (c) the instrumental scattering in the IR region is lower, d) the measurements are conducted close to the true continuum of intensity between the spectral lines. The relationship between magnetic field strength and residual intensity in both spectral lines is nonlinear. The gradient of the magnetic field above sunspots at heights from the photosphere to the upper chromosphere varies within 0.1–0.7 G/km for all the studied sunspots.
Show AbstractDynamics studies of the local hubble cell (the Local Galaxy Group together with the expansion flow around it) with the use of the recent observation data from the Hubble Space Telescope provide new evidence for the existence of dark energy on the distances of several megaparsec. The cell proves to be a natural measurement setup for quantitative determination of the two most important physical characteristics of the nearby Universe, which are the total mass of dark matter (and baryons) in the Group volume and the local density of dark energy. It is found that the estimated local density is close (if not exactly equal) to the global value known from the observations on the distances of about 1000 megaparsecs.
Show AbstractA method utilizing a Hartmann sensor for obtaining estimates of the external scale $L_0$ of turbulent fluctuations and the structural constant $C_n^2$ during the variation of the parameters of the wavefront of a light beam that has passed through turbulence is suggested. The method is based on Zernike polynomial decomposition of phase fluctuations at the given aperture and on analysis of this expansion coefficient’s statistics. Application of the method for making an estimate of the turbulence characteristics in a water cell yielded results that are in good agreement with the estimates obtained by other methods.
Show AbstractConditions for the selective excitation of multimode waveguide high-order modes by power trans-formation of fundamental modes of a tunnel connected waveguide are calculated. It is shown that the power conversion factor can reach 100% under phase-matching conditions, which can be satisfied by the selection of a second waveguide refractive index.
Show Abstract
