Possibility of Geometric Description of Quasiparticles in Solids

New phenomenological approach for the description of elementary collective excitations is proposed. The crystal is considered to be an anisotropic space-time vacuum with a prescribed metric tensor in which the information on electromagnetic crystalline fields is included. The quasiparticles in this space are supposed to be described by the equations structurally similar to the relativistic wave equations for particles in empty space. The generalized Klein-Gordon-Fock equation and the generalized Dirac equation in external electromagnetic field are considered. The applicability of the proposed approach to the case of conduction electron in a crystal is discussed.Comment: 17 pages, latex; to appear in Int. Jnl. Mod. Phy

Impurity relaxation mechanism for dynamic magnetization reversal in a single domain grain

The interaction of coherent magnetization rotation with a system of two-level impurities is studied. Two different, but not contradictory mechanisms, the `slow-relaxing ion' and the `fast-relaxing ion' are utilized to derive a system of integro-differential equations for the magnetization. In the case that the impurity relaxation rate is much greater than the magnetization precession frequency, these equations can be written in the form of the Landau-Lifshitz equation with damping. Thus the damping parameter can be directly calculated from these microscopic impurity relaxation processes

Fluctuation-dissipation considerations and damping models for ferromagnetic materials

The role of fluctuation-dissipation relations (theorems) for the magnetization dynamics with Landau-Lifshitz-Gilbert and Bloch-Bloembergen damping terms are discussed. We demonstrate that the use of the Callen-Welton fluctuation-dissipation theorem that was proven for Hamiltonian systems can give an inconsistent result for magnetic systems with dissipation

On Uniqueness of Boundary Blow-up Solutions of a Class of Nonlinear Elliptic Equations

We study boundary blow-up solutions of semilinear elliptic equations $Lu=u_+^p$ with $p>1$, or $Lu=e^{au}$ with $a>0$, where $L$ is a second order elliptic operator with measurable coefficients. Several uniqueness theorems and an existence theorem are obtained.Comment: To appear in Comm. Partial Differential Equations; 10 page

Adsorption and two-body recombination of atomic hydrogen on 3^3He-4^4He mixture films

We present the first systematic measurement of the binding energy $E_a$ of hydrogen atoms to the surface of saturated $^3$He-$^4$He mixture films. $E_a$ is found to decrease almost linearly from 1.14(1) K down to 0.39(1) K, when the population of the ground surface state of $^3$He grows from zero to $6\times10^{14}$ cm$^{-2}$, yielding the value $1.2(1)\times 10^{-15}$ K cm$^2$ for the mean-field parameter of H-$^3$He interaction in 2D. The experiments were carried out with overall $^3$He concentrations ranging from 0.1 ppm to 5 % as well as with commercial and isotopically purified $^4$He at temperatures 70...400 mK. Measuring by ESR the rate constants $K_{aa}$ and $K_{ab}$ for second-order recombination of hydrogen atoms in hyperfine states $a$ and $b$ we find the ratio $K_{ab}/K_{aa}$ to be independent of the $^3$He content and to grow with temperature.Comment: 4 pages, 4 figures, all zipped in a sigle file. Submitted to Phys. Rev. Let

Overtones of Isoscalar Giant Resonances in medium-heavy and heavy nuclei

A semi-microscopic approach based on both the continum-random-phase-approximation (CRPA) method and a phenomenological treatment of the spreading effect is extended and applied to describe the main properties (particle-hole strength distribution, energy-dependent transition density, partial direct-nucleon-decay branching ratios) of the isoscalar giant dipole, second monopole, and second quadrupole resonances. Abilities of the approach are checked by description of gross properties of the main-tone resonances. Calculation results obtained for the resonances in a few singly- and doubly-closed-shell nuclei are compared with available experimental data.Comment: 12 pages, 14 figures, submitted to Phys. Rev.

Higher order effective low-energy theories

Three well-known perturbative approaches to deriving low-energy effective theories, the degenerate Brillouin-Wigner perturbation theory (projection method), the canonical transformation, and the resolvent methods are compared. We use the Hubbard model as an example to show how, to fourth order in hopping t, all methods lead to the same effective theory, namely the t-J model with ring exchange and various correlated hoppings. We emphasize subtle technical difficulties that make such a derivation less trivial to carry out for orders higher than second. We also show that in higher orders, different approaches can lead to seemingly different forms for the low-energy Hamiltonian. All of these forms are equivalent since they are connected by an additional unitary transformation whose generator is given explicitly. The importance of transforming the operators is emphasized and the equivalence of their transformed structure within the different approaches is also demonstrated.Comment: 14 pages, no figure

Enhanced shot noise in resonant tunnelling via interacting localised states

In a variety of mesoscopic systems shot noise is seen to be suppressed in comparison with its Poisson value. In this work we observe a considerable enhancement of shot noise in the case of resonant tunnelling via localised states. We present a model of correlated transport through two localised states which provides both a qualitative and quantitative description of this effect.Comment: 4 pages, 4 figure

Факторы финансовой несбалансированности обязательной системы пенсионного страхования: анализ российской практики

The aim of the article is to study the impact of tax and tariff policy on the financial balance of the compulsory pension insurance system in Russia, as well as to substantiate proposals for its financial stabilization. The authors analyzed the consequences of regression applied on wages while forming tariffs for pensions. The methods used in this study were economic, statistical and empirical methods, analysis and synthesis, abstraction, systemic-structural approach. The authors analyzed the influence of preferential tariffs for certain types of economic activity and the use of simplified tax systems for organizations on the income of the Pension Fund of the Russian Federation. The work contains the calculation of income shortfalls in the compulsory pension insurance system resulting from the use of regression and tax benefits when calculating insurance payments to the budget of the Pension Fund of Russia. The authors estimated the financial consequences of the pension valorization in the Soviet period and the pension indexation policy in Russia resulted in the rising costs of the Pension Fund of Russia. The conclusion is that the current procedure for determining insurance contributions to the Pension Fund of the Russian Federation, which provides for a large number of benefits, does not correspond to generally accepted world practice and creates major risks for the financial balance of the pension system. This may cause increasing poverty among seniors. Raising the retirement age did not solve the problem of balancing the pension system, but exacerbated it. The regression in the payment of insurance premiums led to a conundrum in Russia, when an increase in wages resulted in the decrease of the Pension Fund of the Russian Federation’s income. This is associated with the precarization of wages and the desire of business to minimize tax payments. The prospect of further research is to study the conditions for financial stabilization of compulsory pension insurance during the Russian economic crisis. The analysis showed that there is a need to create an independent actuarial center for setting tariffs for deductions to the Pension Fund of the Russian Federation, as well as the redistribution of areas of responsibility between the Pension Fund of the Russian Federation and the Ministry of Finance of Russia.Цель исследования — анализ влияния налоговой и тарифной политики на финансовую сбалансированность обязательной системы пенсионного страхования в России, а также обоснование предложений по ее финансовой стабилизации. Подробно проанализированы последствия применения при формировании тарифов на пенсионное обеспечение регрессии по уровню оплаты труда. Методологической основой данного исследования стали экономические, статистические и эмпирические методы, анализ и синтез, абстрагирование, системно-структурный подход. Проанализировано влияние практики использования льготных тарифов для отдельных видов экономической деятельности и применения упрощенных налоговых систем для организаций на доходы ПФР. Рассчитан объем выпадающих доходов системы обязательного пенсионного страхования, возникающий в результате использования регрессии и налоговых льгот при начислении страховых платежей в бюджет Пенсионного фонда России. Дана оценка финансовых последствий проведения валоризации пенсий советского периода и применяемой в российской практике политики индексаций пенсий, в результате которых резко возросли расходы ПФР. Сделаны выводы, что действующий порядок определения процентов отчислений страховых взносов в ПФР, предусматривающий большое количество льгот, не соответствует общепринятой мировой практике и создает основные риски для финансового баланса пенсионной системы. Это может стать причиной роста уровня бедности среди лиц старшего поколения. Повышение пенсионного возраста не решило проблемы сбалансированности пенсионной системы, а, наоборот, обострило ее. Регрессия при уплате страховых взносов обусловила парадоксальную ситуацию в России, когда в результате роста размера заработной платы сокращался объем доходов ПФР, что связано с прекаризацией заработной платы, стремлением бизнеса к минимизации суммы уплаты налогов. Перспектива дальнейших исследований заключается в изучении условий финансовой стабилизации обязательного пенсионного страхования в период кризиса российской экономики. Проведенный авторами анализ показал, что существует необходимость создания независимого актуарного центра по установлению тарифов на отчисления в ПФР, а также перераспределения сфер ответственности между ПФР и Минфином России

Индексация пенсионных выплат: поиски баланса между инфляцией и изменением заработной платы в экономике

The objective of the study is to analyze the effectiveness of the principles of regular indexation of insurance pensions practiced in the Russian pension system, as well as their compliance with the existing similar practice in other countries with pension provision and insurance pension systems. In international practice, these principles correspond to the initial belonging of these systems to one of two basic pension models — continental and Danish (Anglo-Saxon). With an annual increase in pension payments, the governments of countries with pension systems of the first model are guided by changes in the average wage in the economy, the second model — by the consumer price index. The aim of the study is to determine the most optimal formula for indexing insurance pensions in the Russian Federation. The authors use general scientific methods: analysis, modeling and comparison. The article analyzes the practice of indexing pensions that has developed in the Russian Federation and provides a calculation of the results of the valorization of such payments in the early 2000s. It also provides a theoretical justification for the need for the transitions to the indexation of pensions in accordance with the wage index in the economy. The study gives a comparative retrospective analysis of the level of indexation of pensions based on the consumer price index and the index of wage changes. This analysis is based on data from official statistical observations of inflation between 2011 and 2021, as well as the growth of income of employees. As a result of the study, the authors conclude that the annual pension indexation scheme adopted in Russia does not correspond to the modality of the domestic pension system and does not allow ensuring the standard replacement rate. The authors propose their own methodology for calculating the indexation coefficient based on the principles of the functioning of the domestic pension system as a continental-type insurance pension system. In addition, the article provides a calculation of the sources of funding for pension indexation in accordance with changes in wages in the economy.Задача представленного в статье исследования заключается в анализе эффективности исповедуемых в пенсионной системе Российской Федерации принципов периодической индексации страховых пенсий, а также их соответствия сложившейся аналогичной практике в других странах мира, обладающих системами пенсионного обеспечения и страхования. В международной практике эти принципы сформированы исходя из принадлежности национальных пенсионных систем одной из двух базовых пенсионных моделей: континентальной и датской (англо-саксонской). При ежегодном увеличении пенсионных выплат правительства стран с пенсионными системами первой модели ориентируются на изменение средней заработной платы в экономике, второй модели — на изменение индекса потребительских цен. Цель исследования — определить наиболее оптимальную формулу индексации страховых пенсий в Российской Федерации. Авторы применяли общенаучные методы: анализ, моделирование и сравнение. Проанализирована практика индексации пенсий, сложившаяся в Российской Федерации, приведен расчет результатов валоризации таких выплат в начале 2000-х гг. Дано теоретическое обоснование необходимости перехода к индексации пенсий в соответствии с индексом заработной платы в экономике. Приведен сравнительный ретроспективный анализ уровня индексации пенсий, ориентированного на индекс потребительских цен и индекс изменения заработной платы. Этот анализ основан на данных официальных статистических наблюдений за изменением инфляции в период с 2011 по 2021 г., а также роста дохода наемных работников. В результате сделан вывод, что принятая в России схема ежегодной индексации пенсий не соответствует модальности отечественной пенсионной системы и не позволяет обеспечить нормативный коэффициент замещения пенсией утрачиваемого заработка. Авторы предлагают собственную методику расчета коэффициента индексации, основанную на базовых принципах функционирования отечественной пенсионной системы — как системы пенсионного страхования континентального типа. Кроме того, в статье приведен расчет источников финансирования индексации пенсий в соответствии с изменением заработной платы в экономике