Density of kinks just after a quench in an overdamped system

A quench in an overdamped one dimensional $\phi^4$ model is studied by analytical and numerical methods. For an infinite system or a finite system with free boundary conditions, the density of kinks after the transition is proportional to the eighth root of the rate of the quench. For a system with periodic boundary conditions, it is proportional to the fourth root of the rate. The critical exponent predicted in Zurek scenario is put in question.Comment: 4 pages in RevTex + 1 .ps fil

van der Waals coupling in atomically doped carbon nanotubes

We have investigated atom-nanotube van der Waals (vdW) coupling in atomically doped carbon nanotubes (CNs). Our approach is based on the perturbation theory for degenerated atomic levels, thus accounting for both weak and strong atom-vacuum-field coupling. The vdW energy is described by an integral equation represented in terms of the local photonic density of states (DOS). By solving it numerically, we demonstrate the inapplicability of standard weak-coupling-based vdW interaction models in a close vicinity of the CN surface where the local photonic DOS effectively increases, giving rise to an atom-field coupling enhancement. An inside encapsulation of atoms into the CN has been shown to be energetically more favorable than their outside adsorption by the CN surface. If the atom is fixed outside the CN, the modulus of the vdW energy increases with the CN radius provided that the weak atom-field coupling regime is realized (i.e., far enough from the CN). For inside atomic position, the modulus of the vdW energy decreases with the CN radius, representing a general effect of the effective interaction area reduction with lowering the CN curvature.Comment: 15 pages, 5 figure

Spontaneous decay dynamics in atomically doped carbon nanotubes

We report a strictly non-exponential spontaneous decay dynamics of an excited two-level atom placed inside or at different distances outside a carbon nanotube (CN). This is the result of strong non-Markovian memory effects arising from the rapid variation of the photonic density of states with frequency near the CN. The system exhibits vacuum-field Rabi oscillations, a principal signature of strong atom-vacuum-field coupling, when the atom is close enough to the nanotube surface and the atomic transition frequency is in the vicinity of the resonance of the photonic density of states. Caused by decreasing the atom-field coupling strength, the non-exponential decay dynamics gives place to the exponential one if the atom moves away from the CN surface. Thus, atom-field coupling and the character of the spontaneous decay dynamics, respectively, may be controlled by changing the distance between the atom and CN surface by means of a proper preparation of atomically doped CNs. This opens routes for new challenging nanophotonics applications of atomically doped CN systems as various sources of coherent light emitted by dopant atoms.Comment: 10 pages, 4 figure

Spectral properties of interacting magnetoelectric particles

The linear magnetoelectric (ME) effect provides a special route for linking magnetic and electric properties. In microwaves, a local ME effect appears due to the dynamical symmetry breakings of magnetic-dipolar modes (MDMs) in a ferrite disk particle. The fact that for MDMs in a ferrite disk one has evident both classical and quantum-like attributes, puts special demands on the methods used for study of interacting ME particles. A proper model for coupled particles should be based on the spectral characteristics of MDM oscillations and an analysis of the overlap integrals for interacting eigen oscillating ME elements. In this paper, we present theoretical studies of spectral properties of literally coupled of MDM ME disks. We show that there exists the "exchange" mechanism of interaction between the particles, which is distinctive from the magnetostatic interaction between magnetic dipoles. The spectral method proposed in this paper may further the development of a theory of ME "molecules" and realization of local ME composites.Comment: 26 pages, 3 figure

Hamilton Operator and the Semiclassical Limit for Scalar Particles in an Electromagnetic Field

We successively apply the generalized Case-Foldy-Feshbach-Villars (CFFV) and the Foldy-Wouthuysen (FW) transformation to derive the Hamiltonian for relativistic scalar particles in an electromagnetic field. In contrast to the original transformation, the generalized CFFV transformation contains an arbitrary parameter and can be performed for massless particles, which allows solving the problem of massless particles in an electromagnetic field. We show that the form of the Hamiltonian in the FW representation is independent of the arbitrarily chosen parameter. Compared with the classical Hamiltonian for point particles, this Hamiltonian contains quantum terms characterizing the quadrupole coupling of moving particles to the electric field and the electric and mixed polarizabilities. We obtain the quantum mechanical and semiclassical equations of motion of massive and massless particles in an electromagnetic field.Comment: 17 page

Problems with the use of pneumatic screw pumps to transport bulk cargo

An analysis is made of the performance of pneumatic screw pumps at the Bereznikovsky Soda Plant in order be able to transport light soda along a prescribed route and make use of a new nozzle section to make the pumps' operation more reliable. Specific recommendations are made to increase the throughput and reliability of pneumatic screw pumps. The expediency of replacing long lines of screw pumps by chamber pumps is also discussed. © 2013 Springer Science+Business Media New York

Improvement of Approaches to the Verification of the Vaccine Strain <i>Francisella tularensis</i> 15 NIIEG during Long-Term Storage

The aim of the study was to improve the methods for verifying the vaccine strain Francisella tularensis 15 NIIEG during long-term storage under current conditions.Materials and methods. The paper summarizes the results of studying the phenotypic and genetic properties of lyophilized cultures of the vaccine strain F. tularensis 15 NIIEG (1953, 1966, 1969, 1987, 1990, 2003, 2012 and 2013) stored at SCEMAP for a period of one to 60 years.Results and discussion. Previous studies have revealed that freeze-dried cultures of F. tularensis 15 NIIEG generally had the characteristics of the vaccine strain, with the exception of deviations from the regulatory requirements for residual virulence and specific safety. The stability of preservation of deletions in the pilA and pilE genes (the region of differentiation RD19) and the genes encoding lpp lipoprotein (RD18) in the vaccine strain, which was stored for various periods of time in a lyophilized state, has been confirmed. The vaccine-strain-specific mutation C178404T (by the genome of F. tularensis LVS strain, GenBank NCBI no. CP009694) has been identified, and an approach to determine it has been developed. The data obtained are promising as regards using the above deletions in the RD18/RD19 regions in combination with the C178404T mutation to assess the authenticity of the vaccine strain using molecular genetic methods. Thus, the conducted retrospective analysis of the data on the cultures of tularemia microbe vaccine strain from the 1940s to 2013 and the gathered experimental data, made it possible to supplement the uniform requirements for the manufacture, study, maintenance, storage and movement of F. tularensis 15 NIIEG vaccine strain with new evidence. Based on the results obtained, the authors have drawn a draft methodological recommendations of the federal level “Vaccinal strain Francisella tularensis 15 NIIEG: order of handling”

Superradiance from an ultrathin film of three-level V-type atoms: Interplay between splitting, quantum coherence and local-field effects

We carry out a theoretical study of the collective spontaneous emission (superradiance) from an ultrathin film comprised of three-level atoms with $V$-configuration of the operating transitions. As the thickness of the system is small compared to the emission wavelength inside the film, the local-field correction to the averaged Maxwell field is relevant. We show that the interplay between the low-frequency quantum coherence within the subspace of the upper doublet states and the local-field correction may drastically affect the branching ratio of the operating transitions. This effect may be used for controlling the emission process by varying the doublet splitting and the amount of low-frequency coherence.Comment: 15 pages, 5 figure

Solution of the Cauchy Problem for a Time-Dependent Schoedinger Equation

We construct an explicit solution of the Cauchy initial value problem for the n-dimensional Schroedinger equation with certain time-dependent Hamiltonian operator of a modified oscillator. The dynamical SU(1,1) symmetry of the harmonic oscillator wave functions, Bargmann's functions for the discrete positive series of the irreducible representations of this group, the Fourier integral of a weighted product of the Meixner-Pollaczek polynomials, a Hankel-type integral transform and the hyperspherical harmonics are utilized in order to derive the corresponding Green function. It is then generalized to a case of the forced modified oscillator. The propagators for two models of the relativistic oscillator are also found. An expansion formula of a plane wave in terms of the hyperspherical harmonics and solution of certain infinite system of ordinary differential equations are derived as a by-product.Comment: 29 pages, 4 figure