Symplectic structures associated to Lie-Poisson groups

The Lie-Poisson analogues of the cotangent bundle and coadjoint orbits of a Lie group are considered. For the natural Poisson brackets the symplectic leaves in these manifolds are classified and the corresponding symplectic forms are described. Thus the construction of the Kirillov symplectic form is generalized for Lie-Poisson groups.Comment: 30 page

Symplectic structure of the moduli space of flat connections on a Riemann surface

We consider canonical symplectic structure on the moduli space of flat {\g}-connections on a Riemann surface of genus $g$ with $n$ marked points. For {\g} being a semisimple Lie algebra we obtain an explicit efficient formula for this symplectic form and prove that it may be represented as a sum of $n$ copies of Kirillov symplectic form on the orbit of dressing transformations in the Poisson-Lie group $G^{*}$ and $g$ copies of the symplectic structure on the Heisenberg double of the Poisson-Lie group $G$ (the pair ($G,G^{*}$) corresponds to the Lie algebra {\g}).Comment: 20 page

A new species of Xyletinus Latreille, 1809 (Coleoptera: Ptinidae: Xyletininae) from Eocene Baltic amber, with a key to known fossil species

A new extinct species of the genus Xyletinus Latreille, 1809, namely X. (s. str.) lobanovi sp. n., is described and illustrated from Eocene Baltic amber. This new extinct species resembles X. carsteni Háva et Zahradník, 2020 but differs from it in the dull, not shiny pronotum and elytra, uniformly rufous body and appendages and the lesser body size. A new species is close to X. arturi Háva et Zahradník, 2019, but can be distinguished in the lesser body size, flat elytral intervals and the widest in anterior one-third pronotum. A key to fossil species of Xyletinus is provided. Additionally, new fossil records for Ernobius nadravicus Alekseev, 2014 and Xyletinus arturi Háva et Zahradník, 2019 are presented

Parametric x-ray radiation in polycrystals

Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presente

Parametric x-ray radiation in the backward geometry

Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presente

On the Parameters of the QCD-Motivated Potential in the Relativistic Independent Quark Model

In the framework of the relativistic independent quark model the parameters of the QCD-motivated static potential and the quark masses are calculated on the basis of the $1^{--}$ meson mass spectra. The value of the confining potential coefficient is found to be ($0.197\pm 0.005) GeV${}^2$. for quark- antiquark interaction independently on their flavours. The dependence of the quasi-Coulombic potential strength on the interaction distance are consistent with the QCD-motivated behaviour. The$q\bar q$-separations are evaluated and the$e^+e^-$ decay widths are estimated with the help of relativistic modification of the Van Royen-Weisskopf formula.Comment: 10 pages, LaTex; added references for the beginning, changed the last paragraph at the end, made a few stylistic correction

Parametric X-ray radiation in polycrystals

Parametric X-ray radiation produced during the interaction of charged particles with polycrystals is regarded. A review of the existing theories, perspectives of application and performed experiments is presented. The evolution of experimental capabilities as well as the progress in the process comprehension is illustrated. The state of the art of PXR in polycrystals is presented.Розглянуто параметричне рентгенівське випромінювання (ПРВ), що виникає при взаємодії заряджених частинок з полікристалічними мішенями. Представлено огляд сучасного стану дослідження ПРВ в полікристалах: існуючих теорій, перспектив застосування і проведених експериментів з урахуванням розвитку експериментальних можливостей.Рассмотрено параметрическое рентгеновское излучение (ПРИ), возникающее при взаимодействии заряженных частиц с поликристаллическими мишенями. Представлен обзор современного состояния исследования ПРИ в поликристаллах: существующих теорий, перспектив применения и проведенных экспериментов с учетом развития экспериментальных возможностей

Parametric X-ray Radiation in the backward geometry

Parametric X-ray Radiation registered in the backward geometry is analysed. The main properties of the radiation for such geometry are discussed. The advantages of the backward geometry over other configurations regarding the intensity, the spectral width and the possibility to discriminate the contributions form different radiation mechanisms to the total radiation yield are presented.Аналізується параметричне рентгенівське випромінювання, зареєстроване в геометрії «строго назад». Обговорюються основні властивості випромінювання для такої геометрії. Представлено переваги геометрії «строго назад» у порівнянні з іншими геометріями в залежності від інтенсивності, спектральної ширини і можливості поділу внесків від різних механізмів випромінювання в загальний вихід випромінювання.Анализируется параметрическое рентгеновское излучение, зарегистрированное в геометрии «строго назад». Обсуждаются основные свойства излучения для такой геометрии. Представлены преимущества геометрии «строго назад» по сравнению с другими геометриями в зависимости от интенсивности, спектральной ширины и возможности разделения вкладов от различных механизмов излучения в общий выход излучения

The Fuzzy Sphere: From The Uncertainty Relation To The Stereographic Projection

On the fuzzy sphere, no state saturates simultaneously all the Heisenberg uncertainties. We propose a weaker uncertainty for which this holds. The family of states so obtained is physically motivated because it encodes information about positions in this fuzzy context. In particular, these states realize in a natural way a deformation of the stereographic projection. Surprisingly, in the large $j$ limit, they reproduce some properties of the ordinary coherent states on the non commutative plane.Comment: 18 pages, Latex. Minor changes in notations. Version to appear in JHE