Advanced magneto-optical microscopy: Imaging from picoseconds to centimeters - imaging spin waves and temperature distributions (invited)

© 2016 Author(s).Recent developments in the observation of magnetic domains and domain walls by wide-field optical microscopy based on the magneto-optical Kerr, Faraday, Voigt, and Gradient effect are reviewed. Emphasis is given to the existence of higher order magneto-optical effects for advanced magnetic imaging. Fundamental concepts and advances in methodology are discussed that allow for imaging of magnetic domains on various length and time scales. Time-resolved imaging of electric field induced domain wall rotation is shown. Visualization of magnetization dynamics down to picosecond temporal resolution for the imaging of spin-waves and magneto-optical multi-effect domain imaging techniques for obtaining vectorial information are demonstrated. Beyond conventional domain imaging, the use of a magneto-optical indicator technique for local temperature sensing is shown

Research of GIS-services applicability for solution of spatial analysis tasks

Experiments for working out the areas of applying various gis-services in the tasks of spatial analysis are discussed in this paper. Google Maps, Yandex Maps, Microsoft SQL Server are used as services of spatial analysis. All services have shown a comparable speed of analyzing the spatial data when carrying out elemental spatial requests (building up the buffer zone of a point object) as well as the preferences of Microsoft SQL Server in operating with more complicated spatial requests. When building up elemental spatial requests, internet-services show higher efficiency due to cliental data handling with JavaScript-subprograms. A weak point of public internet-services is an impossibility to handle data on a server side and a barren variety of spatial analysis functions. Microsoft SQL Server offers a large variety of functions needed for spatial analysis on the server side. The authors conclude that when solving practical problems, the capabilities of internet-services used in building up routes and completing other functions with spatial analysis with Microsoft SQL Server should be involved

Charge Radii and Magnetic Polarizabilities of the Rho and K* Mesons in QCD String Theory

The effective action for light mesons in the external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The approximation of the Nambu-Goto straight-line string is used to simplify the problem. The Coulomb-like short-range contribution which goes from one-gluon exchange is also neglected. We do not take into account spin-orbital and spin-spin interactions of quarks and observe the $\rho$ and $K^*$ mesons. The wave function of the meson ground state is the Airy function. Using the virial theorem we estimate the mean charge radii of mesons in terms of the string tension and the Airy function zero. On the basis of the perturbative theory, in the small external magnetic field we find the diamagnetic polarizabilities of $\rho$ and $K^*$ mesons: $\beta_\rho =-0.8\times 10^{-4} {fm}^3$, $\beta_{K^*}=-0.57\times 10^{-4} {fm}^3$Comment: 22 pages, no figures, in LaTeX 2.09, typos correcte

Elastic Spin Relaxation Processes in Semiconductor Quantum Dots

Electron spin decoherence caused by elastic spin-phonon processes is investigated comprehensively in a zero-dimensional environment. Specifically, a theoretical treatment is developed for the processes associated with the fluctuations in the phonon potential as well as in the electron procession frequency through the spin-orbit and hyperfine interactions in the semiconductor quantum dots. The analysis identifies the conditions (magnetic field, temperature, etc.) in which the elastic spin-phonon processes can dominate over the inelastic counterparts with the electron spin-flip transitions. Particularly, the calculation results illustrate the potential significance of an elastic decoherence mechanism originating from the intervalley transitions in semiconductor quantum dots with multiple equivalent energy minima (e.g., the X valleys in SiGe). The role of lattice anharmonicity and phonon decay in spin relaxation is also examined along with that of the local effective field fluctuations caused by the stochastic electronic transitions between the orbital states. Numerical estimations are provided for typical GaAs and Si-based quantum dots.Comment: 57 pages, 14 figure

РОСТ ПРИПАЯ И ЕГО ВЛИЯНИЕ НА ЗАМЕРЗАНИЕ ВЕРХНЕГО СЛОЯ ДОННЫХ ОТЛОЖЕНИЙ В ПРИБРЕЖНОЙ ЗОНЕ ГУБЫ БУОР-ХАЯ (МОРЕ ЛАПТЕВЫХ)

Results of the ice and hydrological measurements carried out in the winter of 2014/15 in theTiksiGulf(Buor-KhayaBay) are described. These data served a basis for development of a conceptual thermodynamic model of seasonal freezing of the sea water layers and underlying bottom sediments in the sea-shore zone. The model uses two methods of localization of the phase transition zones: a classical (frontal) one is used for water, while another one within the range of temperatures – for the bottom. For real atmospheric conditions, we investigated specific features of the water freezing through in the shallow coastal zone of theLaptev Sea. The quantitative characteristics of the process were obtained. The calculations demonstrated that the distinguishing feature of the process is a stabilization of the ice thickness, taking place due to essential increasing of a salinity of the sea water. As a result of this, a shallow water body does not frozen through down to the bottom at even the very low air temperatures. Cooled salt waters does not allow liquid to be frozen in pores of the bottom ground. Salinization of the under-ice water layer can cause the melting of fast ice in the shallow water with its simultaneous increase away from the coast. Ice formation in water layers and bottom sediments begins at the same time, although it proceeds differently at different depths. Due to salinization of the bottom ground a continuous frozen zone is not formed, and the whole layer of freezing precipitation is a two-phase (partially frozen) area. As a whole, the model estimates of the process parameters including the motions of the phase fronts agree with known data of direct measurements. Despite such conformity, the model data should be considered as only evaluative ones. If a bottom is flat, the horizontal mixing and advection, which are not reproduced by a one-dimensional model in principle, the actual salinity parameters will most likely not reach the calculated values. However, for small values of the tides in theBuor-KhayaBayand insignificant reverse flows of salt, effect of the last ones does not apparently exert significant influence on the intensity of cooling of the under-ice water layer as well as on the ice formation in upper layers of the bottom within such time scales as a season.Представлены и проанализированы данные стандартных ледовых наблюдений зимой 2014/15 г. в бухте Тикси (губа Буор-Хая, южная часть моря Лаптевых). Описаны особенности изменчивости поля температур в припайном льду и подлёдном слое моря. Данные наблюдений дополнены модельными оценками замерзания слоя воды и верхних слоёв донных отложений

Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays

Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.Comment: 46 pages, 16 figures, Latex, to appear on Nucl. Phys.

Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment

We present the results of a search for nu(mu)-->nu(e) oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4 eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2. This result excludes the LSND allowed region of oscillation parameters with delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.

A study of backward going pp and π−\pi^{-} in νμCC\nu_{\mu}CC interactions with the NOMAD detector

Backward proton and $\pi^-$ production has been studied in $\nu_{\mu}CC$ interactions with carbon nuclei. Detailed analyses of the momentum distributions, of the production rates, and of the general features of events with a backward going particle, have been carried out in order to understand the mechanism producing these particles. The backward proton data have been compared with the predictions of the reinteraction and the short range correlation models.Comment: 29 pages, 14 figures, submitted to Nucl. Phys.

Трансарктика-2019: зимняя экспедиция в Северный Ледовитый океан на НЭС «Академик Трёшников»

Preliminary results of the Transarktika-2019 winter expedition in the Arctic Ocean on the R/V “Akademik Tryoshnikov” are presented. The expedition program included studies on meteorology, hydrology, hydrochemistry, hydrobiology, geology, geophysics and an extensive complex of ice measurements in the Northern Barents Sea from the drifting ice and from the ship. During the expedition, it was possible to complete a wide range of tasks. The data obtained comprise a unique material for a comprehensive study of the current state of the environmental conditions in the Barents Sea. This paper highlights the most significant preliminary results of multidisciplinary observations in various environments, which will be further comprehensively analyzed and published in separate thematic articles.Представлены предварительные результаты зимней экспедиции «Трансарктика-2019» в Северном Ледовитом океане на НЭС «Академик Трёшников». Программа экспедиции включала в себя исследования по метеорологии, гидрологии, гидрохимии, гидробиологии, геологии, геофизике и обширному комплексу измерений ледяного покрова в северной части Баренцева моря с дрейфующего льда и с борта судна. Во время экспедиции удалось выполнить широкий круг задач. Полученные данные представляют собой уникальный материал для всестороннего изучения текущего состояния условий окружающей среды в Баренцевом море. В статье обозначены наиболее значимые предварительные результаты междисциплинарных наблюдений в различных средах, которые в дальнейшем будут всесторонне проанализированы и опубликованы в отдельных тематических статьях