Cooling neutron stars and superfluidity in their interiors

We study the heat capacity and neutrino emission reactions (direct and modified Urca processes, nucleon-nucleon bremsstrahlung, Cooper pairing of nucleons) in matter of supranuclear density of the neutron star cores with superfluid neutrons and protons. Various superfluidity types are analysed (singlet-state pairing and two types of triplet-state pairing, without and with nodes of the gap at a nucleon Fermi surface). The results are used for cooling simulations of isolated neutron stars. Both, the standard cooling and the cooling enhanced by the direct Urca process, are strongly affected by nucleon superfluidity. Comparison of cooling theory of isolated neutron stars with observations of their thermal radiation may give stringent constraints on the critical temperatures of the neutron and proton superfluidities in the neutron star cores.Comment: LaTeX, 85 pages, 23 figures, Physics - Uspekhi (accepted

Production of high energy particles in laser and Coulomb fields and e^+e^- antenna

A strong laser field and the Coulomb field of a nucleus can produce e^{+}e^{-} pairs. It is shown for the first time that there is a large probability that electrons and positrons created in this process collide after one or several oscillations of the laser field. These collisions can take place at high energy resulting in several phenomena. The quasielastic collision e^{+}e^{-} -> e^{+}e^{-} allows acceleration of leptons in the laser field to higher energies. The inelastic collisions allow production of high energy photons e^{+}e^{-}-> 2 gamma and muons, e^{+}e^{-} -> mu^{+}mu^{-}. The yield of high-energy photons and muons produced via this mechanism exceeds exponentially their production through conventional direct creation in laser and Coulomb fields. A relation of the phenomena considered with the antenna-mechanism of multiphoton absorption in atoms is discussed.Comment: 4 page

Thermal structure and cooling of neutron stars with magnetized envelopes

The thermal structure of neutron stars with magnetized envelopes is studied using modern physics input. The relation between the internal (T_i) and local surface temperatures is calculated and fitted by analytic expressions for magnetic field strengths B from 0 to 10^{16} G and arbitrary inclination of the field lines to the surface. The luminosity of a neutron star with dipole magnetic field is calculated and fitted as a function of B, T_i, stellar mass and radius. In addition, we simulate cooling of neutron stars with magnetized envelopes. In particular, we analyse ultramagnetized envelopes of magnetars and also the effects of the magnetic field of the Vela pulsar on the determination of critical temperatures of neutron and proton superfluids in its core

Features of management and implementation of financial and economic activities of various forms and types of institutions

The issues of management and financial and economic activities of state, municipal and private institutions have considered in the article. Mostly in our paper we talk about state and municipal institutions, which, in contrast to private ones, are divided into types (autonomous, budget and state). Each type has a number of unique features that, depending on the situation, give it strong or weak features. The type of institution is mainly due to its scope of detail and the purpose for which it has created. The most progressive type is considered an autonomous institution. It has greater freedom of financial and economic activity (it can open not only personal accounts in the treasury, but accounts in credit institutions, purchases on the basis of regulations approved by the supervisory board, etc.) and has a collegial body represented by a supervisory board consisting of representatives of state and municipal government, workers and independent specialists. The actions of official duty institutions, created for the execution of works and the execution of state (municipal) functions are most constrained. The average «freedom» is endowed with budgetary institutions established to fulfill the state (municipal) assignment in the spheres of education, health, culture, science, social protection, employment of the population, physical culture, sports and other fields. This is the main part of kindergartens, schools, houses of culture, theaters, museums, leisure centers, sports clubs and schools, clinics, hospitals, dispensaries, higher educational institutions, scientific institutes. They are most prevalent in the Russian Federation at both the federal and regional (subjects of the federation) and municipal levels

Quantum Interference Controls the Electron Spin Dynamics in n-GaAs

Manifestations of quantum interference effects in macroscopic objects are rare. Weak localization is one of the few examples of such effects showing up in the electron transport through solid state. Here we show that weak localization becomes prominent also in optical spectroscopy via detection of the electron spin dynamics. In particular, we find that weak localization controls the free electron spin relaxation in semiconductors at low temperatures and weak magnetic fields by slowing it down by almost a factor of two in $n$-doped GaAs in the metallic phase. The weak localization effect on the spin relaxation is suppressed by moderate magnetic fields of about 1 T, which destroy the interference of electron trajectories, and by increasing the temperature. The weak localization suppression causes an anomalous decrease of the longitudinal electron spin relaxation time $T_1$ with magnetic field, in stark contrast with well-known magnetic field induced increase in $T_1$. This is consistent with transport measurements which show the same variation of resistivity with magnetic field. Our discovery opens a vast playground to explore quantum magneto-transport effects optically in the spin dynamics.Comment: 8 pages, 3 figure