Search

The system of the spherical-symmetric vacuum equations of the General Relativity Theory is considered. The general solution to a problem representing two classes of line elements with arbitrary functions g00 and g22 is obtained. The properties of the found solutions are analyzed.

The vacuum static non-spherical equations are considered. The new solutions, which not contain in class of the Schwarzschild-like metrics and also its generalization are obtain. The perspectives for further investigations are discussed.

We study quantum electrodynamics coupled to the matter field on a singular background, which we call defect. For defect on an infinite plane we calculated the mean electromagnetic field. Quantum corrections determining the field near the plane are calculated in the leading order of perturbation theory. We analyse the normalization conditions for the parameters of the defect and calculate the photoelectric function of the charged particle from the defect.

We determine the c-anti-c component of the photon wave function on the basis of (i) the data on the transitions e+ e- -> J/psi(3096), psi(3686), psi(4040), psi(4415), (ii) partial widths of the two-photon decays eta_{c0}(2979), chi_{c0}(3415), chi_{c2}(3556) -> gamma-gamma, and (iii) wave functions of the charmonium states obtained by solving the Bethe-Salpeter equation for the c-anti-c system. Using the obtained c-anti-c component of the photon wave function we calculate the gamma-gamma decay partial widths for radial excitation 2S state, eta_{c0}(3594) -> gamma-gamma, and 2P states chi_{c0}(3849), chi_{c2}(3950) -> gamma-gamma., 20 pages, 8 figures

We demonstrate the possibility of a good description of the processes $\phi (1020)\to \gamma\pi\pi$ and $\phi (1020)\to \gamma f_0(980)$ within the framework of non-relativistic quark model assuming $f_0(980)$ to be dominantly quark--antiquark system. Different mechanisms of the radiative decay, that is, the emission of photon by the constituent quark (additive quark model) and charge-exchange current, are considered. We also discuss the status of the threshold theorem applied to the studied reactions, namely, the behaviour of the decay amplitude at $M_{\pi\pi} \to m_\phi$ and $m_{f_0}\to m_\phi$. In conclusion the arguments favouring the $q\bar q$ origin of $f_0(980)$ are listed.

Modern lasers are yet unable to cause electron-positron pair production in vacuum, however it is possible to notice considerable influence of vacuum polarization on radiation that propagates in such medium. The field strength of modern lasers is not strong enough for creation of electron-positron pair in a vacuum, but the powerful laser beams generates polarization of vacuum which can be established experimentally. In the framework of QED a nonlocal theory of interaction of intensive laser radiation with electron-positron vacuum is developed. Refusing from the Heisenberg-Euler approximation it appears to be possible to calculate non-zero response of vacuum even for a plane wave. It is described by corrections to the Maxwell equations obtained by means of the proper time method. Effects generated by this correction for propagation of wave are analyzed.

Modern lasers are unable yet to cause electron–positron pair production in vacuum, however it is possible to notice considerable influence of vacuum polarization on radiation that propagates in such medium. In our work we present nonlocal theory of interaction of intensive laser radiation with electron–positron vacuum. We refuse from Heisenberg–Euler approximation and it permits us to calculate nonzero response of vacuum even for a plane wave. We show how to use the "proper time" method for calculation of corrections to the Maxwell equations. These equations are solved for the case of plane wave and their solutions are investigated.

The Bethe-Salpeter equations for the light-quark composite systems, q q-bar, are written in terms of spectral integrals. For the q q-bar -mesons characterized by the mass M, spin J and radial quantum number n, the equations are presented for the following (n,M^2)-trajectories: pi_J, eta_J, a_J, f_J, rho_J, omega_J, h_J and b_J., Comment: 42 pages, 5 figures, typos corrected

The physical features of fission pulse generation by a BARS-5 reactor in the “power” regime with a strong internal neutron source are described. It is shown that the pulse parameters are determined primarily by a rate of increase of reactivity, small errors in the calibration of the rods are negligible, safety in emergency situations, including those due to wrong or illegal actions taken by personnel, is ensured by physical factors which prevent the realization of the entire reactivity, introduced by the emergency, in a single pulse.

The quark structure of φ(1020) and f 0(980) is studied on the basis of data on the radiative decays φ(1020) → γπ 0, γη, γη′, γ a 0(980), γ f 0(980) and f 0(980) → γγ. The partial widths are calculated under the assumption that all the mesons under consideration are $$\bar qq$$ states: φ(1020) is a dominantly $$s\bar s$$ state ( $$\eta ' = n\bar nsin\theta + s\bar scos\theta $$ component contributes not more than 1%); η, η′, and π 0 are standard $$q\bar q$$ states, $$\eta = n\bar ncos\theta - s\bar ssin\theta $$ and $$\eta ' = n\bar nsin\theta + s\bar scos\theta $$ with θ≃37°; and f 0(980) is a e5 meson with the flavor wave function $$n\bar ncos\varphi + s\bar ssin\varphi $$ . The transition φ → γπ 0 specifies the admixture of the $$n\bar n$$ component in the φ meson: it is on the order of 0.5%. We argue that this order of $$n\bar n$$ value does not contradict data on the decay φ(1020) → γ a 0(980). The partial widths calculated for the decays φ → γη, γη‱ are in reasonable agreement with experimental data. The measured branching-ratio value Br(φ→γf 0(980))=(3.4±0.4 −0.5 +1.5 ×10−4) requires 25°≤|ϕ|≤90°. For the decay f 0(980) → γγ, the agreement with data, Γ(f 0(980) → γγ)=0.28 −0.13 +0.09 keV, is attained at either ϕ=85°±8° or ϕ=−46°±8°. A simultaneous analysis of the decays φ(1020) → γ f 0(980) and f 0(980) → γγ favors the solution with the negative mixing angle of ϕ=−48°±6°, setting f 0(980) very close to the flavor octet (ϕ octet=±54.7°).

The improvement of the procedure employed for hydrothermal synthesis of aluminophosphates of the AFI type (AlPO4) with the use of triethanolamine as a structure-forming template made it possible to grow large-sized AFI single crystals of high optical quality in the form of hexagonal prisms with a size of up to 2–3 mm along the c axis. The dc electrical conductivity and infrared spectra of the AFI crystals thus obtained were measured.

A method is proposed for on-line monitoring of laser industrial processing. The method is based on optical heterodyne measurements of the Doppler backscattering signal generated in the interaction zone. Qualitative and quantitative information on hydrodynamic flows in the interaction zone can be obtained. A report is given of measurements, carried out at cw CO2 laser radiation intensities up to 1 kW cm-2, on the surfaces of a number of condensed materials irradiated in the monostatic interaction configuration.

We study the field theoretical model of a scalar field in presence of spacial inhomogeneities in form of one and two finite width mirrors (material slabs). The interaction of the scalar field with the defect is described with position-dependent mass term. For the single layer system we develop a rigorous calculation method and derive explicitly the propagator of the theory, S-matrix elements and the Casimir self-energy of the slab. Detailed investigation of particular limits of self-energy is presented, and connection to know cases is discussed. The calculation method is found applicable to the two mirrors case as well. By means of it we derive the corresponding Casimir energy and analyze it. For particular values of the parameters of the model the obtained results recover the Lifshitz formula. We also propose a procedure to obtain unambiguously the finite Casimir \textit{self}-energy of a single slab without reference to any renormalizations. We hope that our approach can be applied to calculation of Casimir self-energies in other demanded cases (such as dielectric ball, etc.), 22 pages, 3 figures, published version, significant changes in Section 4.5

We comment on a recent publication [1] by Fosco, Lombardo and Mazzitelli on Casimir energies for material slabs (`finite width mirrors') and report a discrepancy between results obtained there for a single mirror and some previous calculations. We provide a simple consistency check which proves that the method used in [1] is not reliable when applied to approximations of piecewise constant profile of the mirror. We also present an alternative method for calculation of the Casimir energy in such systems based on our recent work. Our results coincide both with perturbation theory and with some older \cite{Bordag'95} and more recent \cite{Vassilevitch'08} calculations, but differ from those of [1]., Published version, 4 pages

We study the field theoretical model of a scalar field in presence of spacial inhomogeneities in form of one and two finite width mirrors (material slabs). The interaction of the scalar field with the defect is described with position-dependent mass term. Within this model we derive the interaction of two finite width mirrors, establish the correspondence of the model to the Lifshitz formula and construct limiting procedure to obtain finite self-energy of a single mirror without any normalization condition., Comment: 5 pages, based on the presentation on the Ninth Conference on Quantum Field Theory under the influence of External Conditions, Oklahoma, 2009

The content of catecholamines and serotonin in rat cranial cervical ganglion increased during postnatal ontogeny.3H-Quinuclidinyl benzilate binding approached the adult values at the age of one month and then remained at this level, while the binding of3H-dihydroalprenolol increased until maturation and then declined in senescent animals. Early chemical sympathectomy reduced the tissue content of monoamines and had little effect on the binding of labeled ligands.

The density of adrenergic nerve terminals in thyroid gland decreases with age, and this decrease is more pronounced in parafollicular terminals. Density of3H-dihydroalprenolol binding sites increases in 1-month-old rats and decreases in senescent rats. In comparison with control rats, in sympathetically denervated rats the density of nerve fibers increases at the age of 1–6 months and decreases at the age of 12 months. Binding of3H-dihydroalprenolol is considerably higher in immature sympathetically denervated rats.

We present calculations of Casimir energy (CE) in a system of quantized electromagnetic (EM) field interacting with an infinite circular cylindrical shell (which we call `the defect'). Interaction is described in the only QFT-consistent way by Chern-Simon action concentrated on the defect, with a single coupling constant $a$. For regularization of UV divergencies of the theory we use % physically motivated Pauli-Villars regularization of the free EM action. The divergencies are extracted as a polynomial in regularization mass $M$, and they renormalize classical part of the surface action. We reveal the dependence of CE on the coupling constant $a$. Corresponding Casimir force is attractive for all values of $a$. For $a\to\infty$ we reproduce the known results for CE for perfectly conducting cylindrical shell first obtained by DeRaad and Milton., Comment: Typos corrected. Some references added

We consider the problem of modeling of interaction of thin material films with fields of quantum electrodynamics. Taking into account the basic principles of quantum electrodynamics (locality, gauge invariance, renormalizability) we construct a single model for Casimir-like phenomena arising near the film boundary on distances much larger then Compton wavelength of the electron. In this region contribution of Dirac fields fluctuations are not essential and can be neglected. In the model the film is presented by a singular background field concentrated on a 2-dimensional surface and interacting with quantum electromagnetic field. All properties of the film material are described by one dimensionless parameter. For two parallel plane films the Casimir force appears to be non-universal and dependent on material property. It can be both attractive and repulsive. In the model we study scattering of electromagnetic wave on the plane film, an interaction of plane film with point charge, homogeneously charged plane and straight line current. Here, besides usual results of classical electrodynamics the model predicts appearance of anomalous electromagnetic phenomena., Comment: 8 pages,1 figure

We present the method of calculation of radiative decays of composite quark-antiquark systems with different J^{PC}: (Q\bar Q)_{in} -> gamma (Q\bar Q)_{out}. The method is relativistic invariant, it is based on the double dispersion relation integrals over the masses of composite mesons, it can be used for the high spin particles and provides us with the gauge invariant transition amplitudes. We apply this method to the case when the photon is emitted by a constituent in the intermediate state (additive quark model). We perform the momentum operator expansion of the spin amplitudes for the decay processes. The problem of nilpotent spin operators is discussed., 21 pages, 1 figure

The Bethe--Salpeter equations for the quark-antiquark composite systems with different quark masses, such as $q\bar s$ (with $q=u$,$d$), $q\bar Q$ and $s \bar Q$ (with $Q=c$,$b$), are written in terms of spectral integrals. For the mesons characterized by the mass $M$, spin $J$ and radial quantum number $n$, the equations are presented for the $(n,M^2)$-trajectories with fixed $J$. In the spectral-integral technique one can use the energy-dependent forces and get beyond instantaneous approximation. The mixing between states with different quark spin $S$ and angular momentum $L$ are also discussed., 24 pages

We study quantum electrodynamics coupled to the matter field on singular background, which we call defect. For defect on the infinite plane we calculated the fermion propagator and mean electromagnetic field. We show that at large distances from the defect plane, the electromagnetic field is constant what is in agreement with the classical results. The quantum corrections determining the field near the plane are calculated in the leading order of perturbation theory., 16 pages

A complete set of formulae in terms of the moment-operator expansion is presented for the two-meson, two-photon and fermion-antifermion states that can be used in the analysis of scalar (S) and pseudoscalar (P) meson production in anti-p p and gamma-gamma collisions: anti-p p -> SS, PP, SP and gamma gamma -> SS, PP, SP., 21 pages, Latex, no fugures

A cell for obtaining a large temperature gradient (up to 70 K/mm) along a sample for thermoelectric and contact phenomena investigations of a wide class of dielectric and semiconductor materials in a temperature range from 300 to 1000 K is described.

Using radioimmunological, morphometrical, electron microscopic and luminescent methods, comparative analysis of thyroid C-cells and adrenal chromaffin cells has been carried out at guanethidine sympathectomy in young rats. Significant decrease of functional activity of C-cells with concomitant hyperplasia of C-cells population under blockade of sympathetic influences has been revealed. Compared to C-cells, adrenal chromaffinocytes of sympathectomized rats possess higher degree of structural-functional mobilization and are characterized by intensive secretion of catecholamines directed at restoration of tissue neurotransmitter deficit.

A new system of classifying the energy states in molecules is proposed which is simpler and more universal than the existing one. Application of this system to linear molecules makes it possible to treat the latter in the same manner as and together with nonlinear ones.

The character of morphological and functional changes in the thyroid tissue of albino rats was studied by radiometric, histological, and biochemical methods during administration of lithium chloride to the animals for three weeks in doses of 0.5 meq/kg (Group 1), and 1 meq/kg (Group 2) daily. The inhibitory action of lithium chloride on hormone production in the thyroid gland and on the secretion of thyroid hormones into the blood stream was shown to be directly dependent on the dose of the compound and the lithium concentration in the blood. The results of intravital radiometry and morphological analysis of the organs of the animals of group 1 showed some activation of the gland, but secretion of hormones into the blood stream was inhibited. An increase in the lithium concentration inhibited hormone production and the secretion of thyroid hormones into the blood stream.

Taking account of the influence of contact phenomena and electrochemical aging, the change in conduction during aging and regeneration of rutile and rutile-based ceramic monocrystals is based quantitatively on the representations of the motion of F- and V-center clouds. A dependence is established between the processes of aging and regeneration. It is shown that the aging rate is determined by the conductivity of sections in which the propagation of coloring centers occurs and by their mobility.

A considerable decrease in the amount of sympathetic nervous cells in neonatal rats injected guanethidine resulted in the depression of thyroid gland functional activity in 1-month-old animals, there was an apparent parallel increase in the proliferative activity of the gland. A 2/3 thyroidectomy led to the functional tension of the remaining part of the organ. A comparison of compensatory-reparative processes after thyroidectomy has shown similarity of reparative changes in experimental and control rats, however, the degree of repair potential was much higher in the sympathectomized thyroid gland.

Dimensions of sympathetic nerve cells and of their nuclei were studied using various methods of fixation and embedding media, as well as autoradiographic indices of the protein synthesized system of neurocytes in normal rats, and in rats partially sympathectomized at an early age. On the ground of different changes in the average size of neurocytes seen under various methods of fixation, and of decreased labeling intensity of large neurocytes after the injection of the labeled protein biosynthesis precursor there is some reason to believe that large neurocytes may appear in the late reproductive age mainly due to the nerve cell cytoplasm swelling as a consequence of exhaustion of their growth resources.

The changes of the thyroid gland and neurocytes of the cranial sympathetic ganglia were followed in rats of different ages after guanethidine injections with the use of radioimmunological assay, electron microscopy and morphometry. The injection of 15 mg of the drug per kg of body weight within the first two weeks after birth caused the death of over 80% of the cells in the sympathetic ganglion. In the sympathectomized 15-day- and 1-month-old rats the functional activity of the thyroid gland was markedly reduced. Later on, intrathyroid hormonogenesis somewhat increases due, apparently, to partial recovery of the organ adrenergic innervation and increase in the production of thyrotropic hypophysial hormone and calcitonin.

The morphological and functional age-dependent changes have been studied in the thyroid gland of infantile (1-month-old), immature (2- and 3-month-old) and sexually mature (6-month-old) male rats. The decrease in thyroid functional activity with ageing was proved. Chemical sympathectomy (guanethidine at a dose of 15 mg/kg intramuscularly for 14 days after birth) was accompanied not only by morphological reconstruction of the thyroid tissue, but also (especially in 1-month-old rats) by a delay in transport-organic phase of iodine metabolism and a decline in thyroid hormone serum level. Later on, the compensatory hormonogenesis reinforcement occurs as a result of partial adrenergic innervation recovery.

Morphofunctional rearrangement of the thyroid gland resulted from retabolile effect has been studied in 25 tortoises (Testudo horsfieldi) and in 30 white rats. The changes observed evidence in favour of activation of all secretory phases in thyroid hormones. At an overstrained hormonal stress in the thyroid gland, hypofunction of the organ is the initial state in the tortoise, while in the white rat an increased physiological wearing out in thyroid cells and their destruction are noted. Therefore, the relation between proliferation and destruction of thyrocytes is shifted towards the latter.

Neurocytes of the cranial cervical sympathetic ganglion have been studied in normally developing and partly guanidine-desympathized rats at 1 and 12 months of age. In ganglia of the both age groups less than 20% of the cells are preserved. But the somatic development of the animals does not change, and an average volume of the neural cells in the experiment exceeds that of the control. At the age of 1 month in the experimental rats the incorporation of the protein biosynthesis labelled precursor in the neural cells increases, as does its amount evacuated into the terminals at a slow rate. Together with some ultrastructural rearrangements in the perikaryons it could demonstrate certain hyperplastic processes that are possibly directed towards an increased adrenergic innervation in the periphery at the expense of growing processes. Age changes in all the rats occur similarly, nevertheless, certain acceleration of the age dynamics is observed in the partly desympathized animals.

The morphological and functional changes in the thyroid tissue of white rats injected lithium chloride at doses 0.5 mekv/kg and 1.0 mekv/kg (groups 1 and 2, respectively) during three weeks were studied by the radiometric, histological and biochemical methods. The radiometric, histological and biochemical methods. The inhibitory action of lithium chloride on hormonogenesis in the thyroid gland and secretion of thyroid hormones into the blood was proved to be directly related to the lithium dose and concentration in the blood. The data of intravital radiometric and morphological analysis of the organs of the 1st group animals suggest some activization of the gland function, with the secretion of the hormones into the blood being suppressed. Increased concentration of the drug inhibits hormonogenesis and secretion of thyroid hormones into the blood.