Microscopic theory of quantum dot interactions with quantum light: local field effect

A theory of both linear and nonlinear electromagnetic response of a single QD exposed to quantum light, accounting the depolarization induced local--field has been developed. Based on the microscopic Hamiltonian accounting for the electron--hole exchange interaction, an effective two--body Hamiltonian has been derived and expressed in terms of the incident electric field, with a separate term describing the QD depolarization. The quantum equations of motion have been formulated and solved with the Hamiltonian for various types of the QD excitation, such as Fock qubit, coherent fields, vacuum state of electromagnetic field and light with arbitrary photonic state distribution. For a QD exposed to coherent light, we predict the appearance of two oscillatory regimes in the Rabi effect separated by the bifurcation. In the first regime, the standard collapse--revivals phenomenon do not reveal itself and the QD population inversion is found to be negative, while in the second one, the collapse--revivals picture is found to be strongly distorted as compared with that predicted by the standard Jaynes-Cummings model. %The model developed can easily be extended to %%electromagnetic excitation. For the case of QD interaction with arbitrary quantum light state in the linear regime, it has been shown that the local field induce a fine structure of the absorbtion spectrum. Instead of a single line with frequency corresponding to which the exciton transition frequency, a duplet is appeared with one component shifted by the amount of the local field coupling parameter. It has been demonstrated the strong light--mater coupling regime arises in the weak-field limit. A physical interpretation of the predicted effects has been proposed.Comment: 14 pages, 7 figure

Spontaneous decay of an emitter's excited state near a finite-length metallic carbon nanotube

The spontaneous decay of an excited state of an emitter placed in the vicinity of a metallic single-wall carbon nanotube (SWNT) was examined theoretically. The emitter-SWNT coupling strongly depends on the position of the emitter relative to the SWNT, the length of the SWNT, the dipole transition frequency and the orientation of the emitter. In the high-frequency regime, dips in the spectrum of the spontaneous decay rate exist at the resonance frequencies in the spectrum of the SWNT conductivity. In the intermediate-frequency regime, the SWNT conductivity is very low, and the spontaneous decay rate is practically unaffected by the SWNT. In the low-frequency regime, the spectrum of the spontaneous decay rate contains resonances at the antennas resonance frequencies for surface-wave propagation in the SWNT. Enhancement of both the total and radiative spontaneous decay rates by several orders in magnitude is predicted at these resonance frequencies. The strong emitter-field coupling is achieved, in spite of the low Q factor of the antenna resonances, due to the very high magnitude of the electromagnetic field in the near-field zone. The vacuum Rabi oscillations of the population of the excited emitter state are exhibited when the emitter is coupled to an antenna resonance of the SWNT.Comment: 8 pages, 6 figure

Spontaneous decay of excited atomic states near a carbon nanotube

Spontaneous decay process of an excited atom placed inside or outside (near the surface) a carbon nanotube is analyzed. Calculations have been performed for various achiral nanotubes. The effect of the nanotube surface has been demonstrated to dramatically increase the atomic spontaneous decay rate -- by 6 to 7 orders of magnitude compared with that of the same atom in vacuum. Such an increase is associated with the nonradiative decay via surface excitations in the nanotube.Comment: 8 pages, 3 figure

Synthesis and study of complexes of the novel Russian antiviral drug Camphecene with pentacyclic triterpenes of licorice

For the first time, the complexation of pentacyclic triterpenes of licorice (glycyrrhizic acid (GA) and its aglycone, glycyrrhetinic acid (GLA)) with the novel Russian antiviral drug Camphecene (Camph) was investigated. The complexes obtained at different molar ratios were studied using both UV/Vis spectroscopy and mass spectrometry (ESI MS). Formation of the host:guest complexes were registered: GA and GLA molecular complexes (Camph+2GA; Camph+2GLA) with stability constants К = 6.94 106 М-2 and К = 2.89 106 М-2, respectively. The research results demonstrate a considerable potential of ESI MS as a technique for simple and fast detection of formation of the complexes of GA /GLA and the novel drugs

Современные подходы к проектированию устройств тяговой сети железных дорог с помощью BIM-технологий

Optimisation of architecture and construction projects of power supp.ly systems can be achieved with the help of BIM technology, which allows creating a single information model of interrelated processes. It permits to automatically prevent many design mistakes, and BIM makes analysis of project decisions made easier and more visual, significantly improving quality of design, and working documentation.BIM technology is a modern app.roach to design-build-operate cycle. We can say that BIM is organised information about an object, used both at the design and construction stage, and during its operation and dismantling.A single information space, that is a database containing all information about the technical, operational, energy and other features of the facility constitutes an important component of this technology. Due to an accurate and detailed development of the model, this technology makes it possible to carry out various calculations and analyses. A computer model of a new object created during the design process contains all the information about it. With BIM design, a designer at any level has the opp.ortunity and direct need to think about an object as about a holistic model, in real time, and in conformity with its economic component.Competent use of software products for development of BIM models, as well as of the visual programming environment and of the subsequent execution of working documentation, significantly reduces design time and the number of errors. Thus, the costs and time for correcting errors are minimised.The above features of BIM technology allow full use of its advantages when adopting digital modelling in construction of railway power facilities. This process also offers an opp.ortunity to directly relate development of engineering design solutions and electrical engineering calculations within simulation modelling.The objective of the study was to analyse of practical adaptability and features of adoption of this technology while designing catenary. Generalised expertise served to demonstrate key points in implementing relevant information environment, features of development of digital twins of objects of power supp.ly infrastructure and of their operation.Оптимизации архитектурно- строительных проектов систем электроснабжения можно достичь с помощью BIM-технологий, которые позволяют создать единую информационную модель взаимосвязанных процессов. Они позволяют автоматически предотвратить многие ошибки проектирования, а анализ проектных решений становится при помощи BIM проще и нагляднее, значительно повышая качество проектной и рабочей документации. BIM-технология – это современный подход к циклу «проектирование-строительство-эксплуатация». BIM можно охарактеризовать как организованную информацию об объекте, используемую как на стадии проектирования и строительства, так и в период его эксплуатации и демонтажа. Важной составляющей данной технологии является единое информационное пространство – база данных, содержащая всю информацию о технических, эксплуатационных, энергетических и прочих характеристиках объекта. Благодаря точной и детальной проработке модели, эта технология даёт возможность проводить различные расчёты и анализы. В процессе проектирования создается компьютерная модель нового объекта, несущая в себе все сведения о нём. При BIM-проектировании проектировщик любого уровня имеет возможность и прямую необходимость мыслить об объекте, как о целостной модели, в режиме реального времени и в гармоничном единстве с её экономической составляющей. Грамотное применение программных продуктов для разработки BIM-моделей, а также среды визуального программирования и последующего оформления рабочей документации значительно сокращает время проектирования и существенно снижает количество ошибок. Тем самым затраты и время на исправление ошибок минимизируются. Указанные свойства BIM-технологий позволяют в полной мере использовать их преимущества при внедрении цифрового моделирования строительства в области энергетического хозяйства железных дорог. При этом процессе появляется возможность прямой взаимосвязи между разработкой проектных технических решений и расчётной электротехнической частью имитационного моделирования. Целью исследования был анализ практической применимости и специфики внедрения данных технологий при проектировании контактной сети. На основе обобщения имеющегося опыта показаны ключевые моменты реализации необходимой для этого информационной среды, особенности создания цифровых «двойников» объектов инфраструктуры электроснабжения и работы с ними

Analysis of Multiwalled Carbon Nanotubes as Waveguides and Antennas in the Infrared and the Visible Regimes

The propagation of azimuthally symmetric guided waves in multiwalled carbon nanotubes (MWCNTs) was analyzed theoretically in the mid-infrared and the visible regimes. The MWCNTs were modeled as ensembles of concentric, cylindrical, conducting shells. Slightly attenuated guided waves and antenna resonances due to the edge effect exist for not-too-thick MWCNTs in the far- and mid-infrared regimes. Interband transitions hinder the propagation of guided waves and have a deleterious effect on the performance of a finite-length MWCNT as an antenna. Propagation of surface-plasmon waves along an MWCNT with a gold core was also analyzed. In the near-infrared and the visible regimes, the shells behave effectively as lossy dielectrics suppressing surface-plasmon-wave propagation along the gold core.Comment: 13 pages, 8 figure

Comparative analysis of 3D printers based on FDM and SLA technologies

This article describes the process of intellectualization of the fiber-optic sensor (FOS) system. The block diagram of the intelligent system is shown. The modeling of the flowchart of FOS intellectualization in the LabVIEW program is shown