Geometry of Kodaira moduli spaces

A general theorem on the existence of natural torsion-free affine connections on a complete family of compact complex submanifolds in a complex manifold is proved.

     

Apertureless near-field laser nanotechnology

We consider apertureless near-field optics that provides subwavelength resolution. We study the enhancement of the electromagnetic field near nanospheres and under the tip of a scanning probe microscope using the finite difference time-domain (FDTD) method. We discuss the mechanisms of field enhancement connected with the system geometry (“lightning rod effect”) and resonance excitation of local plasmon eigenmodes for different materials of the tip and various geometrical parameters of the system. We describe the possible applications in nano-optics and nanotechnology. We present the experimental achievements in apertureless near-field nanolithography.     

Wheeled Pro(p)file of Batalin-Vilkovisky Formalism

Using a technique of wheeled props we establish a correspondence between the homotopy theory of unimodular Lie 1-bialgebras and the famous Batalin-Vilkovisky formalism. Solutions of the so-called quantum master equation satisfying certain boundary conditions are proven to be in 1-1 correspondence with representations of a wheeled dg prop which, on the one hand, is isomorphic to the cobar construction of the prop of unimodular Lie 1-bialgebras and, on the other hand, is quasi-isomorphic to the dg wheeled prop of unimodular Poisson structures. These results allow us to apply properadic methods for computing formulae for a homotopy transfer of a unimodular Lie 1-bialgebra structure on an arbitrary complex to the associated quantum master function on its cohomology. It is proven that in the category of quantum BV manifolds associated with the homotopy theory of unimodular Lie 1-bialgebras quasi-isomorphisms are equivalence relations.     

On some features of the phase diagram of a ferroic with the cubic paraphase

The phase diagram of a ferroic with the paraphase of symmetry O _h has been studied for a three-dimensional order parameter. In the simplest model, which allows for the existence of a phase of the general position, i.e., the triclinic phase, the region of its existence has been investigated analytically. The invariance of the shape of this region is shown. The conditions providing the formation of a “swallowtail”-type feature in the region of existence of the monoclinic phase are considered. A convenient parametrization is proposed for the representation of the phase diagram, including all possible phases.     

Optical control of spin coherence in singly charged (In,Ga)As/GaAs quantum dots

Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by circularly polarized laser pulses, creating a coherent superposition of an electron and a trion. Time dependent Faraday rotation is used to probe the spin precession of the optically oriented electrons about a transverse magnetic field. The coherence generation can be controlled by pulse intensity, being most efficient for (2n+1)pi pulses.     

Investigation of the influence of gradual substitution K ? Rb on the structure and phase transition in K x Rb1 ? x Pb2Br5 solid solutions

Single crystals of K _x Rb_{1 − x} Pb₂Br₅ solid solutions have been grown and investigated using X-ray diffraction and polarized light microscopy in the temperature range 270–640 K. The regions of existence of the tetragonal (I4/mcm) and monoclinic (P2₁/c) phases have been determined. It has been demonstrated that the partial introduction of rubidium into KPb₂Br₅ leads to an increase in the temperature of the ferroelastic phase transition (P2₁/c↔mmm), so that it approaches the melting temperature. In the solid solutions with x ≈ 0.4−0.5, the temperature region of existence of the orthorhombic phase is narrowed to ≈ 1−2 K. It has been revealed that an increase in the potassium content in the material results in a considerable increase in the incorporation coefficient of Er³⁺ ions. Original Russian Text ? L.I. Isaenko, S.V. Mel’nikova, A.A. Merkulov, V.M. Pashkov, A.Yu. Tarasova, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 3, pp. 554–557.     

Total photoabsorption cross sections for high-Z ELEMENTS in the energy range 7–20 MeV

Total photoabsorption cross sections for 13 isotopes between Sm and Bi were measured in the energy range 7–20 MeV with uncertainties generally better than 0.3 % using the narrow beam attenuation method. The measured cross sections after subtracting the photonuclear contribution are generally in good agreement with the latest NBS calculations of atomic cross sections.