Measuring the Kondo effect in the Aharonov-Bohm interferometer

The conductance ${\cal G}$ of an Aharonov-Bohm interferometer (ABI), with a strongly correlated quantum dot on one arm, is expressed in terms of the dot Green function, $G_{dd}$, the magnetic flux $\phi$ and the non-interacting parameters of the ABI. We show that one can extract $G_{dd}$ from the observed oscillations of ${\cal G}$ with $\phi$, for both closed and open ABI's. In the latter case, the phase shift $\beta$ deduced from ${\cal G} \approx A+B\cos(\phi+\beta)$ depends strongly on the ABI's parameters, and usually $\beta \ne \pi/2$. These parameters may also reduce the Kondo temperature, eliminating the Kondo behavior

The dissipation of the system and the atom in two-photon Jaynes-Cummings model with degenerate atomic levels

The method of perturbative expansion of master equation is employed to study the dissipative properties of system and of atom in the two-photon Jaynes-Cummings model (JCM) with degenerate atomic levels. The numerical results show that the degeneracy of atomic levels prolongs the period of entanglement between the atom and the field. The asymptotic value of atomic linear entropy is apparently increased by the degeneration. The amplitude of local entanglement and disentanglement is suppressed. The better the initial coherence property of the degenerate atom, the larger the coherence loss.Comment: 11 pages, 4 figure

Kondo resonance effect on persistent currents through a quantum dot in a mesoscopic ring

The persistent current through a quantum dot inserted in a mesoscopic ring of length L is studied. A cluster representing the dot and its vicinity is exactly diagonalized and embedded into the rest of the ring. The Kondo resonance provides a new channel for the current to flow. It is shown that due to scaling properties, the persistent current at the Kondo regime is enhanced relative to the current flowing either when the dot is at resonance or along a perfect ring of same length. In the Kondo regime the current scales as $L^{-1/2}$, unlike the $L^{-1}$ scaling of a perfect ring. We discuss the possibility of detection of the Kondo effect by means of a persistent current measurement.Comment: 11 pages, 3 Postscript figure

Test of quantum nonlocality for cavity fields

There have been studies on formation of quantum-nonlocal states in spatially separate two cavities. We suggest a nonlocal test for the field prepared in the two cavities. We couple classical driving fields with the cavities where a nonlocal state is prepared. Two independent two-level atoms are then sent through respective cavities to interact off-resonantly with the cavity fields. The atomic states are measured after the interaction. Bell's inequality can be tested by the joint probabilities of two-level atoms being in their excited or ground states. We find that quantum nonlocality can also be tested using a single atom sequentially interacting with the two cavities. Potential experimental errors are also considered. We show that with the present experimental condition of 5% error in the atomic velocity distribution, the violation of Bell's inequality can be measured.Comment: 14pages, 2figures. accepted to Phys. Rev.

Noise models for superoperators in the chord representation

We study many-qubit generalizations of quantum noise channels that can be written as an incoherent sum of translations in phase space. Physical description in terms of the spectral properties of the superoperator and the action in phase space are provided. A very natural description of decoherence leading to a preferred basis is achieved with diffusion along a phase space line. The numerical advantages of using the chord representation are illustrated in the case of coarse-graining noise.Comment: 8 pages, 5 .ps figures (RevTeX4). Submitted to Phys. Rev. A. minor changes made, according to referee suggestion

СОСТОЯНИЕ ЦЕРЕБРОВАСКУЛЯРНОГО КРОВОТОКА У ЛЮДЕЙ МОЛОДОГО ВОЗРАСТА НА РАННИХ СТАДИЯХ ГИПЕРТОНИЧЕСКОЙ БОЛЕЗНИ

Purpose. To assess arterial circulation inflow and venous outflow in extra and intracranial vessels in young patients with initially diagnosed hypertension with or without consistent hypertensive therapy in correlation to degree and stage of hypertensive disease (HD).Materials and methods. We have examined 82 patients (mean age 36,9±1,5), with HD of the 1-st degree, 63,4 % and 2-nd degree – 36,6 %, HD of the 1-st degree – 61 % and 2-nd degree – 39 %. He control group included – 28 healthy patients of the same age and having normal blood pressure. Circulation in extra and intracranial arteries and veins was studied by ultrasound apparatus Logiq 9 (GEHealthcare,USA).Results. Patients with hypertension disease reliably demonstrated blood flow decrease in carotid and cerebral arteries depending on the degree and stage of HD compared to healthy people with a normal blood pressure. Venous outflow in patients with AH of the 1-st degree and HD of the first stage was increasing objectively in relevance to the patients with AH of the 2-nd degree and HD of the 20nd stage and healthy patients. Later in patients with AH of the 2-nd degree and HD of the 2-nd stage internal jugular vein elasticity decrease was observed accompanied by diminishing of blood stream velocity.Conclusion. Patients with HD of 1-st and 20-nd stage and AH of 1-st and 2-nd degree demonstrate blood stream autoregulation in extra and intracranial arteries of the brain. Changes in venous outflow in AH and HD of the 1-st degree and stage are compensatory. Severity of AH and HD results in cerebral venous congestion confirmed by ultrasound signs.Цель. Оценка артериального притока и венозного оттока в экстра- и интракраниальных сосудах у больных молодого возраста с Г Б, впервые выявленной, и/или при отсутствии постоянной антигипертензивной терапии в зависимости от степени АГ и стадии заболевания.Материалы и методы. Обследовано 82 пациента (средний возраст 36,9±1,5 года): с Г Б I стадии – 63,4 % и II стадии – 36,6 %, АГ 1-й степени – 61 % и 2-й степени – 39 %. Контроль – 28 здоровых лиц того же возраста с нормальным АД. Состояние кровотока в экстра- и интракраниальных артериях и венах проводили ультразвуковым методом на аппарате Logiq 9 (GE Healthcare, USA). Результаты. У больных с Г Б наблюдалось достоверное по сравнению с лицами с нормальным АД снижение показателей кровотока в сонных и мозговых артериях в зависимости от степени АГ и стадии ГБ. Венозный отток у пациентов с АГ 1-й степени и Г Б I стадии достоверно возрастал по отношению к больным с АГ 2-й степени и Г Б II стадии и лицам с нормальным АД. В дальнейшем у больных с АГ 2-й степени и Г Б II стадии происходило снижение податливости ВЯВ, что сопровождалось и снижением в них скорости кровотока.Заключение. У больных молодого возраста с Г Б I–II стадии и АГ 1–2-й степени сохранена ауторегуляция кровотока в экстра- и интракраниальных артериях головы. Изменения со стороны венозного оттока при 1-й степени АГ и I стадии ГБ носят компенсаторный характер, с увеличением степени АГ и стадии ГБ выявляются ультразвуковые признаки венозного застоя в голове

Inelastic Processes in the Collision of Relativistic Highly Charged Ions with Atoms

A general expression for the cross sections of inelastic collisions of fast (including relativistic) multicharged ions with atoms which is based on the genelazition of the eikonal approximation is derived. This expression is applicable for wide range of collision energy and has the standard nonrelativistic limit and in the ultrarelativistic limit coincides with the Baltz's exact solution ~\cite{art13} of the Dirac equation. As an application of the obtained result the following processes are calculated: the excitation and ionization cross sections of hydrogenlike atom; the single and double excitation and ionization of heliumlike atom; the multiply ionization of neon and argon atoms; the probability and cross section of K-vacancy production in the relativistic $U^{92+} - U^{91+}$ collision. The simple analytic formulae for the cross sections of inelastic collisions and the recurrence relations between the ionization cross sections of different multiplicities are also obtained. Comparison of our results with the experimental data and the results of other calculations are given.Comment: 25 pages, latex, 7 figures avialable upon request,submitted to PR

СОСТОЯНИЕ ПАМЯТИ, ВНИМАНИЯ И МЫШЛЕНИЯ У БОЛЬНЫХ С ИШЕМИЧЕСКОЙ БОЛЕЗНЬЮ СЕРДЦА В РАННИЕ И ОТДАЛЕННЫЕ СРОКИ ПОСЛЕ ИМПЛАНТАЦИИ ПОСТОЯННОГО ЭЛЕКТРОКАРДИОСТИМУЛЯТОРА В ЗАВИСИМОСТИ от ИСХОДНЫХ НАРУШЕНИЙ РИТМА СЕРДЦА

Purpose. To compare memory, attention and cognition status in patients with Ischemic heart disease (IHD), before, at early (5–7 days) and long-term (30–40 days) periods after implantation of permanent pacemaker, depending on initial rhythm and conductivity disorders.Materials and methods. 80 patients with IHD: 1st group: 23 patients with atrial fibrillation (AF): 2nd group: 57 patients with the syndrome of sick sinus syndrome (SSS) and/or atrioventricular block (AVB) of a high degree were evaluated for memory, attention and cognition status, before and early (5–7th day) and long-term (30–40th day) periods after implantation of permanent pacemaker, considering initial rhythm and conductivity disorders.Results. Patients of both groups demonstrate decrease in memory, attention and cognition indexes. Implantation of permanent pacemaker at an early period resulted in improvement of certain cognitive functions, predominantly in patients with initial SBWS and AVB than with AF. At long-term period, cognitive functions declined in both groups, likely due to increase of personal and situational anxiety and adaptation to pacemaker work.Conclusion. Permanent pacemaker at early periods improve cognitive function indexes depending on initial rhythm and conductivity disorders. At long-term periods after a month, its decline occurs.Цель. Сравнительная оценка состояния памяти, внимания и мышления у пациентов с ИБС до, в ранние и отдаленные сроки после имплантации постоянного электрокардиостимулятора (ЭКС) в зависимости от исходных нарушений ритма и проводимости.Материалы и методы. У 80 пациентов с ИБС (1-я группа (23 человека) – с фибрилляцией предсердий (ФП); 2-я группа (57 человек) – с синдромом слабости синусового узла (СССУ) и/или с атриовентрикулярными блокадами (АВБ) высоких степеней) проведена сравнительная оценка состояния памяти, внимания и мышления до, первоначально (5–7-й день) и повторно (30–40-й день) после имплантации постоянного ЭКС в зависимости от исходных нарушений ритма и проводимости.Результаты. Установлено, что у пациентов обеих групп наблюдалось снижение показателей памяти, внимания и мышления. Имплантация постоянного ЭКС первоначально вызывала улучшение отдельных показателей когнитивных функций (КФ), в большей степени у пациентов с исходными ССУ и/или АВБ, чем с ФП. При повторном обследовании вновь наступало снижение КФ в обеих группах, что, возможно, было обусловлено ростом личной и ситуационной тревожности в связи с адаптацией к работе ЭКС.Заключение. Применение постоянного ЭКС первоначально способствовало улучшению показателей когнитивных функций в зависимости от исходных нарушений ритма и проводимости. При повторном обследовании через месяц вновь наступало их снижение

Metastable nanosized aluminum powder as a reactant in energetic formulations

Aluminum powder is an important ingredient in many propellant, explosives and pyrotechnic applications. The production of nanosized aluminum powder by the electroexplosion of metal wire has been practices in the former USSR since the mid 1970`s. Differential scanning calorimetry, differential thermal analysis and x-ray phase analysis was performed on aluminum powder both before and after air passivation, as well as aluminum that was protected under kerosene, pentane, toluene and hexane. Earlier Soviet reports of unexplained thermal releases and metastable behavior have been investigated. Anomalous behavior previously reported included phase transformations at temperatures far below melting with the release of heat and chemoluminescence and self sintering of particles with a heat release large enough to melt the powders