Microscopic theory of photonic band gaps in optical lattices

We propose a microscopic model to describe the scattering of light by atoms in optical lattices. The model is shown to efficiently capture Bragg scattering, spontaneous emission and photonic band gaps. A connection to the transfer matrix formalism is established in the limit of a one-dimensional optical lattice, and we find the two theories to yield results in good agreement. The advantage of the microscopic model is, however, that it suits better for studies of finite-size and disorder effects.Comment: 5 pages, 6 figure

The digitalization features of the Russian social media market insurance service

Purpose: The article aims to identify the features of digital techniques introduction and functioning in the insurance industry and the social insurance system. The information techniques used allows to quickly and with the best results to process large amounts of data, thereby increasing the efficiency of all the spheres to reduce social and commercial risks. Design/Methodology/Approach: In order to substantiate introducing the digital techniques expediency in the activity of the insurance system, it is necessary, first, to consider the advantages and disadvantages of information techniques use in the commercial and social insurance. Second, to describe the main digital programs, the implementation of which will increase the targeting and personalization of insurance services. Findings: For the digital techniques introduction in the sphere of insurance relations it is necessary to form the wholly new structure of insurance assets that meet the priorities of the digital economy; to create the necessary conditions for the development and implementation of modern actuarial techniques; to create conditions for increasing incomes and the life standard of the population in order to stimulate demand for insurance services; to change the structure and quality of social services. Practical implications: The results of the study can be implemented in the practice of social funds and insurance companies in order to improve the quality of insurance services. Originality/value: The main contribution of this research is to transfer the processes and mechanisms for the global digital economy and global digital space formation to the social and insurance relations.peer-reviewe

Mode-locked Bloch oscillations in a ring cavity

We present a new technique for stabilizing and monitoring Bloch oscillations of ultracold atoms in an optical lattice under the action of a constant external force. In the proposed scheme, the atoms also interact with a unidirectionally pumped optical ring cavity whose one arm is collinear with the optical lattice. For weak collective coupling, Bloch oscillations dominate over the collective atomic recoil lasing instability and develop a synchronized regime in which the atoms periodically exchange momentum with the cavity field.Comment: 7 pages, 5 figure

Synchronization of Bloch oscillations by a ring cavity

We consider Bloch oscillations of ultracold atoms stored in a one-dimensional vertical optical lattice and simultaneously interacting with a unidirectionally pumped optical ring cavity whose vertical arm is collinear with the optical lattice. We find that the feedback provided by the cavity field on the atomic motion synchronizes Bloch oscillations via a mode-locking mechanism, steering the atoms to the lowest Bloch band. It also stabilizes Bloch oscillations against noise, and even suppresses dephasing due to atom-atom interactions. Furthermore, it generates periodic bursts of light emitted into the counter-propagating cavity mode, providing a non-destructive monitor of the atomic dynamics. All these features may be crucial for future improvements of the design of atomic gravimeters based on recording Bloch oscillations.Comment: 14 pages, 7 figure

STABILIZATION OF BLOCH OSCILLATIONS OF ULTRACOLD ATOMS IN A RING CAVITY

The work presented in this thesis is dedicated to studies of stabilization of Bloch oscillations of ultracold atoms in a one-dimensional vertical optical lattice under the influence of the gravitational force. The atoms simultaneously interact with both the lattice potential and a unidirectionally pumped optical ring cavity whose vertical arm is collinear with the optical lattice. In the proposed scheme, the atoms not only exchange photons between the optical lattice laser beams, but also collectively scatter light from the pump into the reverse cavity mode. The initial investigation of the system without the cavity allows understanding of the importance of the perfectly adiabatic atomic motion in the observation of stable Bloch oscillations and how easily the adiabaticity can be broken due to a very fast switch-on of the lattice or its amplitude and phase modulation. Under certain parameter regimes, adding the ring cavity to the system provides a surprisingly positive feedback on the atomic dynamics. It is found that, while acting back on the atoms, the cavity field establishes a mode-locking mechanism which assists adiabatic rapid passages between adjacent momentum states. Thus, the cavity-induced feedback mechanism enforces the adiabaticity of the process and reveals a regime where the Bloch oscillations are self-synchronized for long times. This stabilization technique is shown to steer the atoms to the lowest Bloch band preventing the problem of interband tunneling. A demonstration is also made of the ability of the system to stabilize the atomic Bloch oscillations against technical amplitude or phase noise and even suppress dephasing due to the atom-atom interactions. Furthermore, the response of the system to the atomic motion is generated in the form of perfectly detectable periodic bursts of light emitted into the counter-propagating cavity mode. Thus, the system offers a continuous and reliable non-destructive method to monitor the Bloch oscillations dynamics without perturbing their periodicity by detecting the scattered light transmitted through the cavity. All features studied in this work may be crucial for future improvements of the design of atomic gravimeters based on recording Bloch oscillations

Author as a corporal subject of a. Huxley’s works

The relevance of the problem studied in the article is conditioned by the fact that A. Huxley’s works are regarded in the context of the modern theory of mimesis for the first time. The aim of the article is to analyze the author’s problem as a corporal subject of Huxley’s works in the context of the modern theory of mimesis. The leading method for studying this problem is the analytical anthropology of literature which allows describing mimetic features and the author’s image as a corporal subject of Huxley’s works. The main attention in the article is paid to the artistically embodied forms of the author’s corporality. The article may be useful for philologists, philosophers, for developing courses and seminars on the history of the English literature, and also within courses on the anthropology of literature. © 2016 Falaleeva et al

Reduced glutathione as a persistence indicator of alien plants of the Amelancheir family

Доведено, що глутатіон відновлений – важливий показник стану та стійкості рослинності. Досліджені види ірги (Amelancheir Med.) за вмістом глутатіону відновленого визнані адаптованими до умов середовища. Встановлено, що зростання вмісту глутатіону відновленого викликане несприятливим впливом абіотичних факторів, зокрема температури. Деякі розбіжності вмісту глутатіону відновленого пояснюються видовими властивостями рослин. Доказано, что глутатион восстановленный является важным показателем состояния и устойчивости растений. Исследованные виды ирги (Amelancheir Med.) по содержанию глутатиона восстановленного признаны адаптированными к условиям среды. Установлено, что увеличение содержания глутатиона восстановленного вызвано негативным влиянием абиотических факторов, в частности температуры. Некоторые расхождения в содержании глутатиона восстановленного объясняются видовыми свойствами растений.It was proved that glutathione is an important indicator of the vegetation condition and persistence. According to the amount of glutathione the studied mespilus species are adapted to the environmental conditions. Increase of the glutathione amount is caused by some abiotic factors, e.g. temperature. Some differences of the glutathione content may be explained by the plants species patterns

Growth of nano dots on the grazing incidence mirror surface under FEL irradiation Analytic approach to modeling

Simple analytic equation is deduced to explain new physical phenomenon detected experimentally growth of nano dots 40 55 nm diameter, 8 13 nm height, 9.4 dots amp; 956;m2 surface density on the grazing incidence mirror surface under the three years irradiation by the free electron laser FLASH 5 45 nm wavelength, 3 degrees grazing incidence angle . The growth model is based on the assumption that the growth of nano dots is caused by polymerization of incoming hydrocarbon molecules under the action of incident photons directly or photoelectrons knocked out from a mirror surface. The key feature of our approach consists in that we take into account the radiation intensity variation nearby a mirror surface in an explicit form, because the polymerization probability is proportional to it. We demonstrate that the simple analytic approach allows to explain all phenomena observed in experiment and to predict new effects. In particular, we show that the nano dots growth depends crucially on the grazing angle of incoming beam and its intensity growth of nano dots is observed in the limited from above and below intervals of the grazing angle and the radiation intensity. Decrease in the grazing angle by 1 degree only from 3 to 2 degree may result in a strong suppression of nanodots growth and their total disappearing. Similarly, decrease in the radiation intensity by several times replacement of free electron laser by synchrotron results also in disappearing of nano dots growt

Effect of the surface roughness on X ray absorption by mirrors operating at extremely small grazing angles

This study theoretically analyzes an increase in X ray absorption by a grazing incidence mirror due to its surface roughness. We demonstrate that the increase in absorption can be several hundred times larger than predicted by the Nevot Croce formula. As a result, absorption enhances by several times compared to a perfectly smooth mirror despite the extremely small grazing angle of an incident X ray beam a fraction of the critical angle of the total external reflection and the high quality of the reflecting surface the roughness height was 0.5 nm in modeling . The main contribution to the absorption increase was dictated by the mid scale roughness waviness of the virgin substrate surface, whose quality thus defines an absorption enhancement. The approach was applied to the analysis of two real mirrors used in a synchrotron BESSY I and a European X ray free electron laser XFEL beamline. The modern surface finishing technology of elastic emission machining provides extremely low substrate waviness, guaranteeing the negligible effect of the surface roughness on the absorption increas

Fragility of Alkali-Boron Melts xLi2O-(100-x)B2O3

Fragility of lithium-boron melts were estimated from vaious approaches. We've received different curves of the "viscosity-temperature" dependences and have counted free fluctuation volume (fg) of investigated melts