Low Energy Properties of the Kondo chain in the RKKY regime

We study the Kondo chain in the regime of high spin concentration where the low energy physics is dominated by the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. As has been recently shown (A. M. Tsvelik and O. M. Yevtushenko, Phys. Rev. Lett 115, 216402 (2015)), this model has two phases with drastically different transport properties depending on the anisotropy of the exchange interaction. In particular, the helical symmetry of the fermions is spontaneously broken when the anisotropy is of the easy plane type (EP). This leads to a parametrical suppression of the localization effects. In the present paper we substantially extend the previous theory, in particular, by analyzing a competition of forward- and backward- scattering, including into the theory short range electron interactions and calculating spin correlation functions. We discuss applicability of our theory and possible experiments which could support the theoretical findings.Comment: 24 pages, 8 figures, 5 appendice

Anderson localization transition with long-ranged hoppings : analysis of the strong multifractality regime in terms of weighted Levy sums

For Anderson tight-binding models in dimension $d$ with random on-site energies $\epsilon_{\vec r}$ and critical long-ranged hoppings decaying typically as $V^{typ}(r) \sim V/r^d$, we show that the strong multifractality regime corresponding to small $V$ can be studied via the standard perturbation theory for eigenvectors in quantum mechanics. The Inverse Participation Ratios $Y_q(L)$, which are the order parameters of Anderson transitions, can be written in terms of weighted L\'evy sums of broadly distributed variables (as a consequence of the presence of on-site random energies in the denominators of the perturbation theory). We compute at leading order the typical and disorder-averaged multifractal spectra $\tau_{typ}(q)$ and $\tau_{av}(q)$ as a function of $q$. For $q<1/2$, we obtain the non-vanishing limiting spectrum $\tau_{typ}(q)=\tau_{av}(q)=d(2q-1)$ as $V \to 0^+$. For $q>1/2$, this method yields the same disorder-averaged spectrum $\tau_{av}(q)$ of order $O(V)$ as obtained previously via the Levitov renormalization method by Mirlin and Evers [Phys. Rev. B 62, 7920 (2000)]. In addition, it allows to compute explicitly the typical spectrum, also of order $O(V)$, but with a different $q$-dependence $\tau_{typ}(q) \ne \tau_{av}(q)$ for all $q>q_c=1/2$. As a consequence, we find that the corresponding singularity spectra $f_{typ}(\alpha)$ and $f_{av}(\alpha)$ differ even in the positive region $f>0$, and vanish at different values $\alpha_+^{typ} > \alpha_+^{av}$, in contrast to the standard picture. We also obtain that the saddle value $\alpha_{typ}(q)$ of the Legendre transform reaches the termination point $\alpha_+^{typ}$ where $f_{typ}(\alpha_+^{typ})=0$ only in the limit $q \to +\infty$.Comment: 13 pages, 2 figures, v2=final versio

Temperature operating mode of the CuBr+Ne+H2(HBr)-laser at change of pumping

The analysis of a temperature mode of the laser on copper bromide vapour using active additives of hydrogen (bromhydrogen) at change of pumping parameters has been carried out. It is shown that introduction of the optimal additive increases the discharge tube wall temperature from 620 up to 720 °С. The increase of wall temperature 50...60 °С more can occur at change of buffer gas pressure from 3,3 to 13,3 kPa, as well as at increase working capacity twice. It is stated that introduction of the additive raises pressure of working substance vapours in the active media of the laser of average diameter 6,7 Pa more due to interaction of bromine, bromhydrogen with copper atoms settled on the tube wall. The peculiarities of laser thermal mode at high frequencies of pulse sequences (up to 100 kHz) have been considered

Security checking experiments with mobile services

In this paper, we continue to investigate th

Drastic facilitation of the onset of global chaos in a periodically driven Hamiltonian system due to an extremum in the dependence of eigenfrequency on energy

The Chirikov resonance-overlap criterion predicts the onset of global chaos if nonlinear resonances overlap in energy, which is conventionally assumed to require a non-small magnitude of perturbation. We show that, for a time-periodic perturbation, the onset of global chaos may occur at unusually {\it small} magnitudes of perturbation if the unperturbed system possesses more than one separatrix. The relevant scenario is the combination of the overlap in the phase space between resonances of the same order and their overlap in energy with chaotic layers associated with separatrices of the unperturbed system. One of the most important manifestations of this effect is a drastic increase of the energy range involved into the unbounded chaotic transport in spatially periodic system driven by a rather {\it weak} time-periodic force, provided the driving frequency approaches the extremal eigenfrequency or its harmonics. We develop the asymptotic theory and verify it in simulations.Comment: 5 pages, 4 figures, LaTeX, to appear PR

Directed transient long-range transport in a slowly driven Hamiltonian system of interacting particles

We study the Hamiltonian dynamics of a one-dimensional chain of linearly coupled particles in a spatially periodic potential which is subjected to a time-periodic mono-frequency external field. The average over time and space of the related force vanishes and hence, the system is effectively without bias which excludes any ratchet effect. We pay special attention to the escape of the entire chain when initially all of its units are distributed in a potential well. Moreover for an escaping chain we explore the possibility of the successive generation of a directed flow based on large accelerations. We find that for adiabatic slope-modulations due to the ac-field transient long-range transport dynamics arises whose direction is governed by the initial phase of the modulation. Most strikingly, that for the driven many particle Hamiltonian system directed collective motion is observed provides evidence for the existence of families of transporting invariant tori confining orbits in ballistic channels in the high dimensional phase spaces

Quasiclassical magnetotransport in a random array of antidots

We study theoretically the magnetoresistance $\rho_{xx}(B)$ of a two-dimensional electron gas scattered by a random ensemble of impenetrable discs in the presence of a long-range correlated random potential. We believe that this model describes a high-mobility semiconductor heterostructure with a random array of antidots. We show that the interplay of scattering by the two types of disorder generates new behavior of $\rho_{xx}(B)$ which is absent for only one kind of disorder. We demonstrate that even a weak long-range disorder becomes important with increasing $B$. In particular, although $\rho_{xx}(B)$ vanishes in the limit of large $B$ when only one type of disorder is present, we show that it keeps growing with increasing $B$ in the antidot array in the presence of smooth disorder. The reversal of the behavior of $\rho_{xx}(B)$ is due to a mutual destruction of the quasiclassical localization induced by a strong magnetic field: specifically, the adiabatic localization in the long-range Gaussian disorder is washed out by the scattering on hard discs, whereas the adiabatic drift and related percolation of cyclotron orbits destroys the localization in the dilute system of hard discs. For intermediate magnetic fields in a dilute antidot array, we show the existence of a strong negative magnetoresistance, which leads to a nonmonotonic dependence of $\rho_{xx}(B)$.Comment: 21 pages, 13 figure

Эндохирургические методики в лечении прогрессирующей трубной беременности

Research purpose: to increase the efficiency of endosurgical treatment of women with progressive tubal pregnancy. Research method: prospective analysis. Research subjects: in 75 female patients, to whom salpingotomy and salpingorrhaphy had been per-formed, tubal patency was found; in 10% - tubal patency was laboured; in 9,5% of patients there was an obstruction. In 52,9% of women, to whom salpingotomic orifice was not sutured, tubal patency was found; in 32,4% of patients tubal patency was disturbed; in 14,7% the fallopian tube was obstructed and in 17,6% of patients tubo-peritoneal fistula formed. Uterine pregnancy rate of salpingotomy and salpingorrhaphy - 34,1%, of women, to whom salpingotomic orifice was not sutured - 20,6%. Performance of endoscopic salpingotomy with suture of the defect at isthmial and ampullar location of the fetal ovum helps to increase the efficien-cy of surgical treatment of the ectopic pregnancy.Цель исследования - повышение эффективности эндохирургического лечения женщин с прогрессирующей трубной беременностью. Под наблюдением находились 75 пациенток с прогрессирующей трубной беременностью. Методы исследования: проспективный анализ. У 80,5% больных, которым выполнена сальпинготомия и сальпингография, маточная труба оказалась проходимой, у 10% проходимость трубы была затруднена, у 9,5% пациенток труба была непроходимой. У 52,9% женщин, которым сальпинготомическое отверстие не ушивали, маточная труба проходима, у 32,4% пациенток проходимость трубы нарушена, у 14,7% труба непроходима и у 17,6% больных сформировался трубно-перитонеальный свищ. Выполнение эндоскопической сальпинготомии с ушиванием дефекта при истмической и ампулярной локализации плодного яйца позволяет улучшить результаты хирургического лечения внематочной беременности

Прогностичне значення маркерів ендотеліальної дисфункції в діагностиці ступеня атеросклеротичного ураження коронарних судин у хворих із гострим інфарктом міокарда з коронарним стентуванням

Мета. Оцінити рівні інгібітора активатора плазміногену 1 типу (ІАП-1) та асиметричного діметіларгініну (АДМА) у хворих із гострим інфарктом міокарда (ГІМ) в залежності від наявності або відсутності цукрового діабету 2-го типу (ЦД2) та характеру ураження коронарних артерій (KА), а також їх прогностичне значення щодо ступеня атеросклеротичного ураження коронарних судин. Матеріали і методи. Обстежено 130 хворих, 44 (33,85%) жінки та 86 (66,15%) чоловіків. Усіх пацієнтів розподілено на дві групи: основну - 73 хворих із ГІМ і супутнім ЦД2, серед них 43 чоловіки і 30 жінок, середній вік яких становив (62,73 ± 1,39) року, та порівняльну - 57 хворих із ГІМ без ЦД2, серед них 43 чоловіки і 14 жінок, середній вік яких становив (63,98 ± 1,47) року. Контрольну групу склали 20 практично здорових осіб (10 чоловіків і 10 жінок, середній вік яких становив (60,85 ± 1,37) року). Усім хворим проводили коронарографію вінцевих судин серця у стандартних проекціях за допомогою ангіографа Siemens Axiom Artis. Вміст АДМА встановлювали імуноферментним методом, використовуючи комерційну систему тестування «Immunodiagnostik» компанії ADMA Xpress ELISA Kit (Австрія), ІАП-1 - також імуноферментним методом, використовуючи комерційну тест-систему виробництва фірми Technoclone PAI-1 ELISA Kit (Австрія). Результати. У хворих із ГІМ незалежно від того, мали вони ЦД2 чи не мали, рівні ІАП-1 та АДМА підвищені у порівнянні з контрольною групою (р < 0,05). У хворих з гемодинамічно значущим стенозом (ГЗC) KА (70% і більше) визначено підвищення рівнів ІАП-1 та АДМА як за наявності, так і за відсутності ЦД2 (р < 0,05).У хворих із ГІМ та дифузним ураженням (ДУ) KА як із супутнім ЦД2, так і без нього рівні ІАП-1 та АДМА були достовірно вище, ніж у хворих без ДУ KА (р < 0,05). Висновки. Порівняння площ під ROC-кривими показало, що більшу діагностичну цінність для прогнозування ДУ KА у хворих із ГІМ та супутнім ЦД2 має ІАП-1, ніж АДМА. Рівні ІАП-1 та АДМА доцільно визначати для прогнозування ГЗC KА та діагностики ДУ коронарного русла з тим, щоб проводити профілактику розвитку ускладнень ГІМ