UV continuum emission and diagnostics of hydrogen-containing non-equilibrium plasmas

For the first time the emission of the radiative dissociation continuum of the hydrogen molecule ($a^{3}\Sigma_{g}^{+} \to b^{3}\Sigma_{u}^{+}$ electronic transition) is proposed to be used as a source of information for the spectroscopic diagnostics of non-equilibrium plasmas. The detailed analysis of excitation-deactivation kinetics, rate constants of various collisional and radiative transitions and fitting procedures made it possible to develop two new methods of diagnostics of: (1) the ground $X^{1}\Sigma_{g}^{+}$ state vibrational temperature $T_{\text{vib}}$ from the relative intensity distribution, and (2) the rate of electron impact dissociation (d[\mbox{H_{2}}]/dt)_{\text{diss}} from the absolute intensity of the continuum. A known method of determination of $T_{\text{vib}}$ from relative intensities of Fulcher-$\alpha$ bands was seriously corrected and simplified due to the revision of $d \to a$ transition probabilities and cross sections of $d \gets X$ electron impact excitation. General considerations are illustrated with examples of experiments in pure hydrogen capillary-arc and H$_{2}$+Ar microwave discharges.Comment: REVTeX, 25 pages + 12 figures + 9 tables. Phys. Rev. E, eprint replaced because of resubmission to journal after referee's 2nd repor

A Modified Scheme of Triplectic Quantization

A modified version of triplectic quantization, first introduce by Batalin and Martnelius, is proposed which makes use of two independent master equations, one for the action and one for the gauge functional such that the initial classical action also obeys that master equation.Comment: 8 page

Large magnetothermal conductivity in GdBaCo_{2}O_{5+x} single crystals

To study the effects of paramagnetic spins on phonons, both the in-plane and the c-axis heat transport of GdBaCo_{2}O_{5+x} (GBCO) single crystals are measured at low temperature down to 0.36 K and in magnetic field up to 16 T. It is found that the phonon heat transport is very strongly affected by the magnetic field and nearly 5 times increase of the thermal conductivity in several Tesla field is observed at 0.36 K. It appears that phonons are resonantly scattered by paramagnetic spins in zero field and the application of magnetic field removes such strong scattering, but the detailed mechanism is to be elucidated.Comment: 5 pages, 5 figures, accepted for publication in Phys. Rev.

Large magneto-thermal effect and the spin-phonon coupling in a parent insulating cuprate Pr_{1.3}La_{0.7}CuO_4

The magnetic-field (H) dependence of the thermal conductivity \kappa of Pr_{1.3}La_{0.7}CuO_4 is found to show a pronounced minimum for in-plane fields at low temperature, which is best attributed to the scattering of phonons by free spins that are seen by a Schottky-type specific heat and a Curie-Weiss susceptibility. Besides pointing to a strong spin-phonon coupling in cuprates, the present result demonstrates that the H-dependence of the phonon heat transport should not be naively neglected when discussing the \kappa(H) behavior of cuprates, since the Schottky anomaly is ubiquitously found in cuprates at any doping.Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev.

Competition and coexistence of antiferromagnetism and superconductivity in RBa_2Cu_3O_{6+x} (R = Lu, Y) single crystals

We use c-axis resistivity and magnetoresistance measurements to study the interplay between antiferromagnetic (AF) and superconducting (SC) ordering in underdoped RBa_2Cu_3O_{6+x} (R = Lu, Y) single crystals. Both orders are found to emerge from an anisotropic 3D metallic state, upon which antiferromagnetism opposes superconductivity by driving the doped holes towards localization. Despite the competition, the superconductivity sets in before the AF order is completely destroyed and coexists with latter in a certain range of hole doping. We find also that strong magnetic fields affect the AF-SC interplay by both suppressing the superconductivity and stabilizing the Neel order.Comment: 7 pages, 6 figure

The Higher Education Adaptability to The Digital Economy

Digitalization processes are global and performed in all spheres of economic activities. The development of the digital economy correlates with the dynamics of educational, scientific and technical, and innovative activities in the country. Higher education particularly affects the development of the digital economy because it is a system training highly qualified personnel, conducting quality research, and generating innovations. The purpose of the article is the identification of promising vectors of higher education system development under the conditions of digitalization of national economy. Section 1 of the article presents the authors’ methodological approach to assessment the impact of educational, research, and innovation components on digital economy development. The implementation of the authors’ approach covers the phased use of methods of statistical, index, cluster and system analysis. The influence of higher education on the structural components of the digital economy (educational, research, innovative ones) is grounded. The result of the study was the identification of main trends in the development of higher education under the conditions of digital economy. The problems of the development of higher education are systematized in the groups: contextual, legal, organizational and economic, financial, logistical problems, and problems of internationalization. Based on the results of the analysis, the authors conclude the necessity of development of a conceptual base for increasing the digital adaptability of the higher education system to new socio-economic conditions. Section 2 of the article describes the concept of the digital adaptability strategy of the higher education system. The concept was developed on the base of structural and functional, systemic and synergetic, and institutional approaches. The proposed concept is based on the idea of deepening the long-term partnership of universities with stakeholders within the Quadruple Helix model. In the conclusion section, the authors highlight the key priorities of the digital adaptability strategy of the higher education system

Hidden Galilean symmetry, conservation laws and emergence of spin current in the soliton sector of chiral helimagnet

Motivated by the spin current problem in chiral helimagnet, we rigorously elucidated the hidden Galilean invariance in the chiral XY model under the magnetic field. The Lie group analysis is applied to the differential equations of the continuum theory of the chiral helimagnet with the parity-violating Dzyaloshinskii-Morya coupling under a transversal magnetic field. Lie point symmetries and the invariant solutions under these symmetries are found. They present sliding solutions that come up as a consequence of breaking of both spin rotational symmetry by the external magnetic field and a parity violation due to the Dzyaloshinskii-Morya interaction. We found that variational symmetries are related with translations in space and time, the corresponding energy and momentum conservation laws are derived. We therefore succeeded in justifying the existence of the transport spin current in chiral helimagnet.Comment: 14 page

Resistive Transition and Upper Critical Field in Underdoped YBa_2Cu_3O_{6+x} Single Crystals

A superconducting transition in the temperature dependence of the ab-plane resistivity of underdoped YBa_2Cu_3O_{6+x} crystals in the range T_c<30 K has been investigated. Unlike the case of samples with the optimal level of doping, the transition width increased insignificantly with magnetic field, and in the range T_c<13 K it decreased with increasing magnetic field. The transition point T_c(B) was determined by analyzing the fluctuation conductivity. The curves of B_{c2}(T) measured in the region T/T_c>0.1 did not show a tendency to saturation and had a positive second derivative everywhere, including the immediate neighborhood of T_c. The only difference among the curves of B_{c2}(T) for different crystal states is the scales of T and B, so they can be described in terms of a universal function, which fairly closely follows Alexandrov's model of boson superconductivity.Comment: 10 Revtex pages, 6 figures, uses psfig.st

Collisional kinetics of non-uniform electric field, low-pressure, direct-current discharges in H2_{2}

A model of the collisional kinetics of energetic hydrogen atoms, molecules, and ions in pure H$_2$ discharges is used to predict H$_\alpha$ emission profiles and spatial distributions of emission from the cathode regions of low-pressure, weakly-ionized discharges for comparison with a wide variety of experiments. Positive and negative ion energy distributions are also predicted. The model developed for spatially uniform electric fields and current densities less than $10^{-3}$ A/m$^2$ is extended to non-uniform electric fields, current densities of $10^{3}$ A/m$^2$, and electric field to gas density ratios $E/N = 1.3$ MTd at 0.002 to 5 Torr pressure. (1 Td = $10^{-21}$ V m$^2$ and 1 Torr = 133 Pa) The observed far-wing Doppler broadening and spatial distribution of the H$_\alpha$ emission is consistent with reactions among H$^+$, H$_2^+$, H$_3^+$, and H$^-H$ ions, fast H atoms, and fast H$_2$ molecules, and with reflection, excitation, and attachment to fast H atoms at surfaces. The H$_\alpha$ excitation and H$^-$ formation occur principally by collisions of fast H, fast H$_2$, and H$^+$ with H$_2$. Simplifications include using a one-dimensional geometry, a multi-beam transport model, and the average cathode-fall electric field. The H$_\alpha$ emission is linear with current density over eight orders of magnitude. The calculated ion energy distributions agree satisfactorily with experiment for H$_2^+$ and H$_3^+$, but are only in qualitative agreement for H$^+$ and H$^-$. The experiments successfully modeled range from short-gap, parallel-plane glow discharges to beam-like, electrostatic-confinement discharges.Comment: Submitted to Plasmas Sources Science and Technology 8/18/201