Nanostructures and impurity centers in cryogenic environment

International audienc

Relativistic description of asymmetric fully heavy tetraquarks in the diquark-antidiquark model

Masses of the ground, orbitally and radially excited states of the asymmetric fully heavy tetraquarks, composed of charm (c) and bottom (b) quarks and antiquarks are calculated in the relativistic diquark-antidiquark picture. The relativistic quark model based on the quasipotential approach and quantum chromodynamics is used to construct the quasipotentials of the quark-quark and diquark-antidiquark interactions. These quasipotentials consist of the short-range one-gluon exchange and long-distance linear confinement interactions. Relativistic effects are consistently taken into account. A tetraquark is considered as a bound state of a diquark and an antidiquark which are treated as a spatially extended colored objects and interact as a whole. It is shown that most of the investigated tetraquarks states (including all ground states) lie above the fall-apart strong decay thresholds into a meson pair. As a result they can be observed as wide resonances. Nevertheless, several orbitally excited states lie slightly above or even below these fall-apart thresholds, thus they could be narrow states.Comment: 24 pages, 1 figur

Features of Perception of Interpersonal Interaction Situations

У статті визначено узагальнювальні фактори оцінки ситуацій міжособистісної взаємодії, реконструйовано категоріальну структуру суб’єкта, що обумовлює сприйняття та аналіз ситуацій, пов’язаних з навчальним процесом студентів. The author identifies generalized factors assessing the situations of interpersonal interaction. The categorial structure of subjects reconstruction, which determines the perception and analysis of situations connected with the students’ educational process is considered in the article

Взаимодействие Продуктивных и Интерактивных Технологий в Образовательном Процессе Высшей Школы

The article identifies productive technology as a set of interactive learning tools, which allows students and teachers to create personal educational products of intellectual discovery: project, invention, design, presentation, task, hypothesis, etc. Productive activity is a personality trait manifesting itself in its relation to cognitive activity, which presupposes the state of readiness and desire for independence. It is aimed at the assimilation of social experience, human knowledge, and implementation of techniques related to educational and professional activities. The interaction of productive interactive technologies is a set of software, technical, computer, and communication equipment, as well as ways and innovative methods of their application, aimed to ensure high efficiency and informatization of the educational process. Multimedia is the latest computer technologies and techniques including animated graphics, video, sound, interactive features, as well as the use of remote access, external resources, and databases. A quantitative, qualitative, and statistical analysis, conducted upon the completion of the experimental work, has demonstrated positive changes in the productive cognitive activity of students in the experimental group.El artículo identifica la tecnología productiva como un conjunto de herramientas de aprendizaje interactivo, que permite a los estudiantes y profesores crear productos educativos personales de descubrimiento intelectual: proyecto, invención, diseño, presentación, tarea, hipótesis, etc. La actividad productiva es un rasgo de personalidad que se manifiesta en su relación con la actividad cognitiva, que presupone el estado de preparación y el deseo de independencia. Está dirigido a la asimilación de la experiencia social, el conocimiento humano y la implementación de técnicas relacionadas con actividades educativas y profesionales. La interacción de tecnologías interactivas productivas es un conjunto de software, equipo técnico, informático y de comunicación, así como formas y métodos innovadores de su aplicación, destinados a garantizar una alta eficiencia e informatización del proceso educativo. Multimedia es lo último en tecnologías y técnicas informáticas, que incluyen gráficos animados, video, sonido, funciones interactivas, así como el uso de acceso remoto, recursos externos y bases de datos. Un análisis cuantitativo, cualitativo y estadístico, realizado al finalizar el trabajo experimental, ha demostrado cambios positivos en la actividad cognitiva productiva de los estudiantes en el grupo experimental.в статье технология продуктивности определяется как набор интерактивных инструментов обучения, позволяющих учащимся и учителям создавать персональные образовательные продукты: проект, изобретение, дизайн, презентация, задание, гипотеза и т.д. Продуктивная деятельность - это личностная черта, проявляющаяся в ее отношении к познавательной деятельности, что предполагает готовность и стремление к независимости. Она направлена на усвоение социального опыта, человеческих знаний и внедрение методов, связанных с образовательной и профессиональной деятельностью. Взаимодействие продуктивных и интерактивных технологий представляет собой совокупность программного, технического, компьютерного и коммуникационного оборудования, а также способов и инновационных методов их применения, направленных на обеспечение высокой эффективности и информатизации образовательного процесса. Мультимедиа - это новейшие компьютерные технологии и технологии, включающие анимационную графику, видео, звук, интерактивные функции, а также использование удаленного доступа, внешних ресурсов и баз данных. Количественный, качественный и статистический анализ, проведенный по завершении экспериментальной работы, продемонстрировал положительные изменения в продуктивной познавательной деятельности учащихся экспериментальной группы

Strong nonlinear optical response of graphene flakes measured by four-wave mixing

We present the first experimental investigation of nonlinear optical properties of graphene flakes. We find that at near infrared frequencies a graphene monolayer exhibits a remarkably high third-order optical nonlinearity which is practically independent of the wavelengths of incident light. The nonlinear optical response can be utilized for imaging purposes, with image contrasts of graphene which are orders of magnitude higher than those obtained using linear microscopy.Comment: 4 pages, 5 figure

Re-entrant resonant tunneling

We study the effect of electron-electron interactions on the resonant-tunneling spectroscopy of the localized states in a barrier. Using a simple model of three localized states, we show that, due to the Coulomb interactions, a single state can give rise to two resonant peaks in the conductance as a function of gate voltage, G(Vg). We also demonstrate that an additional higher-order resonance with Vg-position in between these two peaks becomes possibile when interactions are taken into account. The corresponding resonant-tunneling process involves two-electron transitions. We have observed both these effects in GaAs transistor microstructures by studying the time evolution of three adjacent G(Vg) peaks caused by fluctuating occupation of an isolated impurity (modulator). The heights of the two stronger peaks exibit in-phase fluctuations. The phase of fluctuations of the smaller middle peak is opposite. The two stronger peaks have their origin in the same localized state, and the third one corresponds to a co-tunneling process.Comment: 9 pages, REVTeX, 4 figure