Quasi-linear theory of multimode free-electron lasers with an inhomogeneous frequency broadening

assuming that the number of excited modes is large and their phases are random a quasi-linear theory of interaction of ultrarelativistic electron beam with the field of a high-quality cavity is developed. The saturation effects in FELs with an inhomogeneous frequency broadening are described. It is shown that in the case of very large excesses over threshold the efficiency of FELs tends to 50% but the emitted energy is distributed in a very wide spectral interval.     

Averages in the B(t) field representation

Conditions are deduced subject to which conversion to the B(t) field representation can give rise to new effects.     

Employing Higgs boson production at photon colliders to discriminate between the two Higgs doublet model and the standard model in the process <Emphasis Type="Italic">eγ</Emphasis> → <Emphasis Type="Italic">eh</Emphasis>

The possibility of employing experiments at photon colliders to discriminate between various models of electroweak-symmetry breaking is discussed for the case where experiments at LHC and at future linear electron-positron colliders reveal no disagreement with the predictions of the Standard Model (SM)—that is, the case of an SM-like scenario. The two Higgs boson doublet model (2HDM) is considered as an alternative to the SM. A comparison of the cross sections obtained for the process eγ → eh within the SM and the natural 2HDM shows that investigation of this cross section would make it possible to discriminate between these models of electroweak-symmetry breaking reliably and to confirm or disprove the results obtained by studying the reaction γγ → h.     

Poisson deformations of symplectic quotient singularities

We establish a connection between smooth symplectic resolutions and symplectic deformations of a (possibly singular) affine Poisson variety.In particular, let V be a finite-dimensional complex symplectic vector space and G⊂Sp(V) a finite subgroup. Our main result says that the so-called Calogero-Moser deformation of the orbifold V/G is, in an appropriate sense, a versal Poisson deformation. That enables us to determine the algebra structure on the cohomology of any smooth symplectic resolution X?V/G (multiplicative McKay correspondence). We prove further that if is an irreducible Weyl group and , then no smooth symplectic resolution of V/G exists unless G is of types .     

Highly selective surface-wave resonators for terahertz frequency range formed by metallic Bragg gratings

In the frame of the quasi-optical approach we solve the diffraction problem and describe surface modes confined at a metallic plate with a shallow grating of finite length. We prove that such planar grating can form a highly selective surface-wave Bragg resonator. For a given material conductivity and grating length, we find the optimum corrugation depth that provides the maximum value of Q factor. These results are applicable for developing resonators for terahertz frequency bands.     

Relaxation under conditions of strong interaction

A method is developed for considering a nonequilibrium transition in an isolated system when the correlation time [2] and relaxation time are of the same order. The perturbation V in the Hamiltonian of (1.1) is not restricted in any way. The method is based on the assumption [4] that it is possible to use a representation in which the indeterminacy of the energy of a nonstationary system appears explicitly.     

Fullerene C6 0 Aggregates in Polymethyl Methacrylate Films

The structure of aggregates of fullerene C_{6 0} introduced into films of radical polymethyl methacrylate in the stage of solution preparation was studied by wide-angle X-ray diffraction.     

Direct visualization of layer-by-layer self-assembled multilayers of organometallic polymers

Direct visualization of organometallic-organic and novel all-organometallic multilayer superlattices prepared by layer-by-layer assembly of cationic/anionic polyferrocenylsilane and anionic polystyrene sulfonate polyelectrolytes using a gold coating/transmission electron microscopy (TEM) technique is reported.