General principles for the non-equilibrium relaxation of populations in quantum materials

We examine the problem of how excited populations of electrons relax after they have been excited by a pump. We include three of the most important relaxation processes: (i) impurity scattering; (ii) Coulomb scattering; and (iii) electron-phonon scattering. The relaxation of an excited population of electrons is one of the most fundamental processes measured in pump/probe experiments, but its interpretation remains under debate. We show how several common assumptions about non-equilibrium relaxation that are pervasive in the field may not hold under quite general conditions. The analysis shows that non-equilibrium relaxation is more complex than previously thought, but it yields to recently developed theoretical methods in non-equilibrium theory. In this work, we show how one can use many-body theory to properly interpret and analyze these complex systems. We focus much of the discussion on implications of these results for experiment.Comment: 13 pages, 10 figure

Formation of dark excitons in monolayer transition metal dichalcogenides by a vortex beam: optical selection rules

Monolayer transition metal dichalcogenides host tightly-bound excitons, which dominate their optoelectronic response even at room temperatures. Light beams are often used to study these materials with the polarization - often termed as the spin angular momentum of the light - providing the mechanism for exciting excitonic states. Light beams, however, can also carry an orbital angular momentum by creating helical structures of their phase front. In this work, we consider a Laguerre-Gaussian beam possessing an orbital angular momentum in addition to the spin angular momentum to create excitons in monolayer transition metal dichalcogenides. We derive optical selection rules that govern the allowed transitions to various exciton series using symmetry arguments. Our symmetry considerations show that we can create dark excitons using these high-order optical beams opening up new avenues for creating long-lived dark excitons with the potential of exploiting them in quantum information processing and storage

Investigation of the use of new solar air heaters for drying agricultural products

This article discusses the study of energy-saving technologies that have become a topical issue today. Types of solar heating collectors, the principles of operation, and their constructive structure were studied. A new technology developed based on the analyses proposed to dry the agricultural products. Also, in the current presentation, the technologies used in the context of the technologies and the reduction issues and technologies have been considered. Experimental experiments are also provided based on the proposed technology in seasonal (spring, summer, autumn, winter). In the study case, the operation principle of the operation of a flat surface air heater is studied. The article provides the basics of twice the shortening of air canals to a common full-length sunny air heater. The study learned the issues of reducing the local resistance ratio of the device concerning a common full-wide air heater. Raise the temperature of the sun's agents discussed in the article; reduction issues are analyzed

Features of the Values of Foreign Students from Kyrgyzstan in UrFU

В статье рассмотрены особенности ценностных ориентиров студентов из Киргизии, обучающихся в УрФУ, полученные в ходе исследований. Сделан анализ ценностей и выявлены тенденции, изменения в поведенческой среде студентов. Описаны причинно-следственные связи ценностных основ и ситуации в современном мире.This article discusses the features of the value orientations of students from Kyrgyzstan studying in UrFU, obtained in research. We did an analysis of values and identified trends, changes in the students’ behavioral environment. We described the cause-effect relationships of value foundations and the situation in the modern world

Boundary value problems of degenerate integro-differential equations on the boundary of the region with application in filtration

Boundary value problems for ordinary and integro-differential equations degenerating on the boundary of the region are considered. The existence of solutions is proven and a priori estimates for the solutions of the problems are obtained. The method of semidiscretization is applied for approximate solution, and the convergence of the approximate method is proven