Surface acoustic wave modulation of single photon emission from GaN/InGaN nanowire quantum dots

On-chip quantum information processing requires controllable quantum light sources that can be operated on-demand at high-speeds and with the possibility of in-situ control of the photon emission wavelength and its optical polarization properties. Here, we report on the dynamic control of the optical emission from core-shell GaN/InGaN nanowire (NW) heterostructures using radio frequency surface acoustic waves (SAWs). The SAWs are excited on the surface of a piezoelectric lithium niobate crystal equipped with a SAW delay line onto which the NWs were mechanically transferred. Luminescent quantum dot (QD)-like exciton localization centers induced by compositional fluctuations within the InGaN nanoshell were identified using stroboscopic micro-photoluminescence (micro-PL) spectroscopy. They exhibit narrow and almost fully linearly polarized emission lines in the micro-PL spectra and a pronounced anti-bunching signature of single photon emission in the photon correlation experiments. When the nanowire is perturbed by the propagating SAW, the embedded QD is periodically strained and its excitonic transitions are modulated by the acousto-mechanical coupling, giving rise to a spectral fine-tuning within a ~1.5 meV bandwidth at the acoustic frequency of ~330 MHz. This outcome can be further combined with spectral detection filtering for temporal control of the emitted photons. The effect of the SAW piezoelectric field on the QD charge population and on the optical polarization degree is also observed. The advantage of the acousto-optoelectric over other control schemes is that it allows in-situ manipulation of the optical emission properties over a wide frequency range (up to GHz frequencies).Comment: arXiv admin note: text overlap with arXiv:1902.0791

Software selection based on analysis and forecasting methods, practised in 1C

The research focuses on the problem of a "1C: Enterprise 8" platform inboard mechanisms for data analysis and forecasting. It is important to evaluate and select proper software to develop effective strategies for customer relationship management in terms of sales, as well as implementation and further maintenance of software. Research data allows creating new forecast models to schedule further software distribution

Under the influence of new educational technologies: the theory of electrolytic dissociation

The article describes a computer programs for study of the chemistry section, training calculations and knowledge testРассмотрены компьютерные программы для изучения студентами химии, выполнения ими практических заданий и проверки знани

Teaching Academic English to Russian-speaking Academic Staff: The Case of the Office of Academic Writing

The paper discusses the preliminary results of teaching academic writing to scientific and academic staff at South Ural State University (national research university) within the framework of advanced training courses. The 36 and 72-hour training programs were developed by the academic and methodological department of the Office of Academic Writing. The Office was opened at the university in 2016 in order to improve the academic literacy of the university’s academic staff, develop professional communication skills in English, and assist authors who aspire to get their papers published in top rated scientific journals indexed in the scientific citation databases Scopus and Web of Science. Upon completion of these programs, authors of scientific papers gain knowledge about the basics of academic writing, the structure of a scientific paper, the English scientific style and its lexical and grammatical features, as well as editing a paper, working with scientific citation databases, and elaborating a publishing strategy. We conducted a study from October 2016 to December 2018 and calculated data on the attendees’ affiliation (an institute or higher school), the contingent (position), and the importance of the offered training programs (the number of attendees in each course). The obtained data indicates that representatives of social-humanitarian and technical fields show a special interest in the courses. The courses of academic writing are most popular among associate professors who have experience in publishing papers in Russian. Authors are especially interested in intensive practice-oriented programs. Upon completion of the courses and with the support of the Office of Academic Writing, attendees prepared scientific texts in English and submitted them to top rated journals and conference proceedings. The educational activity of the Office of Academic Writing can be developed through elaboration and implementation of new advanced training programs, including the distance ones. Their effectiveness will be evaluated by an increase in the publication activity of the university’s employees

Bichromatic dressing of a quantum dot detected by a remote second quantum dot

We demonstrate an information transfer mechanism between two dissimilar remote InAs/GaAs quantum dots weakly coupled to a common photonic crystal microcavity. Bichromatic excitation in the s state of one of the dots leads to the formation of dressed states due to the coherent coupling to the laser field, in resonance with the quantum dot. Information on the resulting dressed structure is read out through the photoluminescence spectrum of the other quantum dot, as well as the cavity mode. The effect is also observed upon exchange of the excitation and detection quantum dots. This quantum dot intertalk is interpreted in terms of a cavity-mediated coupling involving acoustic phonons. A master equation for a three-level system coherently pumped by the two lasers quantitatively describes the behavior of our system. Our result presents an important step towards scalable solid-state quantum networking based on coupled multi-quantum-dot-cavity systems, without the need to use identical quantum emittersThis work was supported by the Spanish MINECO under Contract No. MAT2011-22997, by CAM under Contract No. S2009/ESP-1503, and by the FP7 ITN Spin-optronics (237252). C.S-M. and E.C. acknowledge FPI gran

PROFESSIONAL DEFORMATION AND PROFESSIONAL DEGRADATION IN THE UNDERSTANDING OF FUTURE PSYCHOLOGISTS

The peculiarities of understanding the concepts of professional deformation and professional degradation in students studying Psychology are studied and analyzed. The essence of the concepts of professional deformation and professional degradation is clarified, the main differences, causes of development, types and signs of developing dysfunctions are revealed. Specific errors in the understanding of phenomena among students are highlighted.Изучаются и анализируются особенности понимания понятий профессиональная деформация и профессиональная деградация у студентов, обучающихся по направлению «Психология». Уточняется суть понятий профессиональной деформации и профессиональной деградации, выявляются основные различия, причины развития, виды и признаки развивающихся дисфункций. Выделяются конкретные ошибки в понимании феноменов у студентов

NbS3_{3}: A unique quasi one-dimensional conductor with three charge density wave transitions

Through transport, compositional and structural studies, we review the features of the charge-density wave (CDW) conductor of NbS$_{3}$ (phase II). We highlight three central results: 1) In addition to the previously reported CDW transitions at $T_{P1}$ = 360\,K and $T_{P2}$ = 150\,K, another CDW transition occurs at a much higher temperature $T_{P0}$ = 620-650\,K; evidence for the non-linear conductivity of this CDW is presented. 2) We show that CDW associated with the $T_{P2}$ - transition arises from S vacancies acting as donors. Such a CDW transition has not been observed before. 3) We show exceptional coherence of the $T_{P1}$-CDW at room-temperature. Additionally, we report on the effects of uniaxial strain on the CDW transition temperatures and transport.Comment: 16 pages, 18 figure

Diffuse versus square-well confining potentials in modelling AA@C60_{60} atoms

Attention: this version-$2$ of the manuscript differs from its previously uploaded version-$1$ (arXiv:1112.6158v1) and subsequently published in 2012 J. Phys. B \textbf{45} 105102 only by a removed typo in Eq.(2) of version-$1$; there was the erroneous factor "2" in both terms in the right-hand-side of the Eq.(2) of version-$1$. Now that the typo is removed, Eq.(2) is correct. A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C$_{60}$ cage potential in calculations of endohedral atoms $A$@C$_{60}$, by a more realistic diffuse potential is explored. The photoionization of endohedral H@C$_{60}$ and Xe@C$_{60}$ is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of $A$@C$_{60}$ atoms are largely insensitive to the degree $\eta$ of diffuseness of the potential borders, in a reasonably broad range of $\eta$'s. Alternatively, these spectra are found to be insensitive to discontinuity of the square-well potential either. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for $A$@C$_{60}$ spectra, are recommended for future studies.Comment: 11 pages, 4 figure

2-(4-Chloro­benzo­yl)-1-(diamino­methyl­ene)hydrazinium chloride monohydrate

In the cation of the title compound, C8H10ClN4O+·Cl−·H2O, the guanidinium group is planar (maximum deviation = 0.0001 Å) and nearly perpendicular to carboxamide group, making a dihedral angle of 87.0 (3)°. The N atoms of the guanidine fragment have a planar trigonal configuration and the N atom of the carboxamide group adopts a pyramidal configuration. In the crystal structure, inter­molecular N—H⋯O, N—H⋯Cl and O—H⋯Cl hydrogen bonds link the cations, anions and water mol­ecules into layers parallel to the bc plane