Equilibrium currents in chiral systems with non-zero Chern number

We describe simple quantum-mechanical approach to calculating equilibrium particle current along the edge of a system with non-trivial band spectrum topology. The approach does not require any a priori knowledge of the band topology and, as a matter of fact, treats topological and non-topological contributions to the edge currents on the same footing. We illustrate its usefulness by demonstrating the existence of `topologically non-trivial' particle currents along the edges of three different physical systems: two-dimensional electron gas with spin-orbit coupling and Zeeman magnetic field, surface state of a topological insulator, and kagome antiferromagnet with Dzyaloshinskii-Moriya interaction. We describe relation of our results to the notion of orbital magnetization.Comment: 8 pages, 4 figure

Equilibrium currents in chiral systems with nonzero Chern number

pre-printWe describe a simple quantum-mechanical approach to calculating equilibrium particle current along the edge of a system with nontrivial band spectrum topology. The approach does not require any a priori knowledge of the band topology and, as a matter of fact, treats topological and nontopological contributions to the edge currents on the same footing.We illustrate its usefulness by demonstrating the existence of "topologically nontrivial" particle currents along the edges of three different physical systems: two-dimensional electron gas with spin-orbit coupling and Zeeman magnetic field, surface state of a topological insulator, and kagom´e antiferromagnet with Dzyaloshinskii-Moriya interaction. We describe the relationship of our results to the notion of orbital magnetization

Holstein polaron in the presence of disorder

Non-local, inhomogeneous and retarded response observed in experiments is reproduced by introducing the Inhomogeneous Momentum Average (IMA) method to study single polaron problems with disorder in the on-site potential and/or spatial variations of the electron-phonon couplings and/or phonon frequencies. We show that the electron-phonon coupling gives rise to an additional inhomogeneous, strongly retarded potential, which makes instant approximations questionable. The accuracy of IMA is demonstrated by comparison with results from the approximation free Diagrammatic Monte Carlo (DMC) method. Its simplicity allows for easy study of many problems that were previously unaccessible. As an example, we show how inhomogeneities in the electron-phonon coupling lead to nonlocal, retarded response in scanning tunneling microscopy (STM) images.Comment: 4 pages, 3 figure

Фармакоепідеміологічні та фармакоекономічні аспекти споживання препаратів блокаторів рецепторів ангіотензину ІІ на фармацевтичному ринку України

The results of the analysis of the range, economic accessibility and consumption of angiotensin II receptor blockers (ARBs II) compared to ACE inhibitors within 2008-2013 have been considered. The choice of the optimal trade names (TN) has been substantiated according to the results of the “cost minimization” pharmacoeconomic analysis and the missed opportunities index. During the study period there was the increase in the range of ARBs II at the pharmaceutical market of Ukraine mainly due to foreign drugs. Drugs of ARBs II are characterized by lower availability for an average Ukrainian compared to ACE inhibitors. In the dynamics of the years the consumption volumes of ARBs II increased, but they were significantly inferior to the volume of ACE inhibitors consumption. During the research period the leaders of consumption were drugs of losartan, valsartan and candesartan, which were mostly generics. According to the results of the pharmacoeconomic analysis and the calculation of the missed opportunities some cheaper drugs of ARBs II have been identified. Using these drugs compared to more expensive ones allows to treat additionally a certain number of patients.Рассмотрены результаты анализа ассортимента, экономической доступности и объемов потребления блокаторов рецепторов ангиотензина II (БРА II) по сравнению с ингибиторами АПФ в течение 2008-2013 годов и обоснования выбора наиболее оптимальных торговых названий (ТН) по результатам фармакоэкономического анализа «минимизация затрат» и показателя упущенных возможностей. В течение исследуемого периода происходило увеличение ассортимента БРА II на фармацевтическом рынке Украины преимущественно за счет препаратов иностранного производства. Препараты БРА II характеризуются более низкой доступностью для среднестатистического жителя Украины по сравнению с ингибиторами АПФ. В динамике лет объемы потребления БРА II возросли, однако значительно уступали объемам потребления ИАПФ. Лидерами потребления в течение исследуемого периода являются препараты лозартана, вальсартана и кандесартана, которые в значительной степени представлены генерическими препаратами. По результатам фармакоэкономического анализа и расчета показателя упущенных возможностей определены отдельные предложения менее затратных препаратов БРА II, использование которых по сравнению с более затратными позволяет дополнительно пролечить определенное количество больных.Висвітлені результати аналізу асортименту, економічної доступності та обсягів споживання блокаторів рецепторів ангіотензину ІІ (БРА II) в порівнянні з інгібіторами АПФ протягом 2008-2013 років та обґрунтування вибору найбільш оптимальних торгових назв (ТН) за результатами фармакоекономічного аналізу «мінімізація витрат» і показника втрачених можливостей. Протягом досліджуваного періоду відбувалося збільшення асортименту БРА ІІ на фармацевтичному ринку України переважно за рахунок препаратів іноземного виробництва. Препарати БРА ІІ характеризуються більш низькою доступністю для середньостатистичного жителя України у порівнянні з інгібіторами АПФ. В динаміці років обсяги споживання БРА ІІ зростали, проте значно поступались обсягам споживання ІАПФ. Лідерами споживання протягом досліджуваного періоду у групі БРА ІІ є препарати лозартану, вальсартану і кандесартану, які значною мірою представлені генеричними препаратами. За результатами фармакоекономічного аналізу і розрахунку показника втрачених можливостей визначені окремі пропозиції менш витратних препаратів БРА ІІ, використання яких порівняно з більш витратними дає можливість додатково пролікувати певну кількість хворих

Smearing of the 2D Kohn anomaly in a nonquantizing magnetic field: Implications for the interaction effects

Thermodynamic and transport characteristics of a clean two-dimensional interacting electron gas are shown to be sensitive to the weak perpendicular magnetic field even at temperatures much higher than the cyclotron energy, when the quantum oscillations are completely washed out. We demonstrate this sensitivity for two interaction-related characteristics: electron lifetime and the tunnel density of states. The origin of the sensitivity is traced to the field-induced smearing of the Kohn anomaly; this smearing is the result of curving of the semiclassical electron trajectories in magnetic field.Comment: 4.5 pages, 3 figures, published versio

Ducks on the torus: existence and uniqueness

We show that there exist generic slow-fast systems with only one (time-scaling) parameter on the two-torus, which have canard cycles for arbitrary small values of this parameter. This is in drastic contrast with the planar case, where canards usually occur in two-parametric families. Here we treat systems with a convex slow curve. In this case there is a set of parameter values accumulating to zero for which the system has exactly one attracting and one repelling canard cycle. The basin of the attracting cycle is almost the whole torus.Comment: To appear in Journal of Dynamical and Control Systems, presumably Vol. 16 (2010), No. 2; The final publication is available at www.springerlink.co

Determination of Different Biological Factors on the Base of Dried Blood Spot Technology

It is well-known that distinct biological indices (analytes) have distinct variability. We try to use some mathematical algorithms to pick out a set of blood parameters which give an opportunity to retrieve the initial volume of the blood spotted, and use it to calculate exact concentrations of analyts interesting to a physician. For our analysis we used the database of biochemical blood parameters obtained in Russian Scientific Center of Roentgen-Radiology during 1995-2000, which includes more than 30000 of patients.Comment: 5 page