The Behaviour of the Green Function for the BFKL Pomeron with Running Coupling

We analyse here in LO the physical properties of the Green function solution for the BFKL equation. We show that the solution obeys the orthonormality conditions in the physical region and fulfills the completeness requirements. The unintegrated gluon density is shown to consists of a set of few poles with parameters which could be determined by comparison with the DIS data of high precision

Indirect Evidence for New Physics at the 10 TeV Scale

We show that the supersymmetric extension of the Standard Model modifies the structure of the low lying BFKL discrete pomeron states (DPS) which give a sizable contribution to the gluon structure function in the HERA x and Q2 region. The comparison of the gluon density, determined within DPS with N=1 SUSY, with data favours a supersymmetry scale of the order of 10 TeV. The DPS method described here could open a new window to the physics beyond the Standard Model.Comment: 14 pages, 6 figure

Effect of disorder studied with ferromagnetic resonance for arrays of tangentially magnetized sub-micron Permalloy discs fabricated by nanosphere lithography

Tangentially magnetized trigonal arrays of sub-micron Permalloy discs are characterized with ferromagnetic resonance to determine the possible contributions to frequency and linewidth from array disorder. Each array is fabricated by a water-surface self-assembly lithographic technique, and consists of a large trigonal array of 700 nm diameter magnetic discs. Each array is characterized by a different degree of ordering. Two modes are present in the ferromagnetic resonance spectra: a large amplitude, `fundamental' mode and a lower amplitude mode at higher field. Angular dependence of the resonance field in a very well ordered array is found to be negligible for both modes. The relationship between resonance frequency and applied magnetic field is found to be uncorrelated with array disorder. Linewidth is found to increase with increasing array disorder

H{\alpha} Imaging of Nearby Seyfert Host Galaxies

We used narrowband interference filters with the CCD imaging camera on the Nickel 1.0 meter telescope at Lick Observatory to observe 31 nearby (z < 0.03) Seyfert galaxies in the 12 {\mu}m Active Galaxy Sample. We obtained pure emission line images of each galaxy in order to separate H{\alpha} emission from the nucleus from that of the host galaxy. The extended H{\alpha} emission is expected to be powered by newly formed hot stars, and correlates well with other indicators of current star formation in these galaxies: 7.7 {\mu}m PAH, far-infrared, and radio luminosity. Relative to what would be expected from recent star formation, there is a 0.8 dex excess of radio emission in our Seyfert galaxies. The nuclear H{\alpha} luminosity is dominated by the AGN, and is correlated with the hard X-ray luminosity. There is an upward offset of 1 dex in this correlation for the Seyfert 1s due to a strong contribution from the Broad Line Region. We found a correlation between star formation rate and AGN luminosity. In spite of selection effects, we concluded that the absence of bright Seyfert nuclei in galaxies with low SFRs is real, albeit only weakly significant. We used our measured spatial distributions of H{\alpha} emission to determine what these Seyfert galaxies would look like when observed through fixed apertures at high redshifts. Although all would be detectable emission line galaxies at any redshift, most would appear dominated by HII region emission. Only the most luminous AGN would still be identified at z~0.3.Comment: 13 pages, 11 figures, accepted for publication in Ap

Fast Mesh Refinement in Pseudospectral Optimal Control

Mesh refinement in pseudospectral (PS) optimal control is embarrassingly easy --- simply increase the order $N$ of the Lagrange interpolating polynomial and the mathematics of convergence automates the distribution of the grid points. Unfortunately, as $N$ increases, the condition number of the resulting linear algebra increases as $N^2$; hence, spectral efficiency and accuracy are lost in practice. In this paper, we advance Birkhoff interpolation concepts over an arbitrary grid to generate well-conditioned PS optimal control discretizations. We show that the condition number increases only as $\sqrt{N}$ in general, but is independent of $N$ for the special case of one of the boundary points being fixed. Hence, spectral accuracy and efficiency are maintained as $N$ increases. The effectiveness of the resulting fast mesh refinement strategy is demonstrated by using \underline{polynomials of over a thousandth order} to solve a low-thrust, long-duration orbit transfer problem.Comment: 27 pages, 12 figures, JGCD April 201

Quasiharmonic elastic constants corrected for deviatoric thermal stresses

The quasiharmonic approximation (QHA), in its simplest form also called the statically constrained (SC) QHA, has been shown to be a straightforward method to compute thermoelastic properties of crystals. Recently we showed that for non-cubic solids SC-QHA calculations develop deviatoric thermal stresses at high temperatures. Relaxation of these stresses leads to a series of corrections to the free energy that may be taken to any desired order, up to self-consistency. Here we show how to correct the elastic constants obtained using the SC-QHA. We exemplify the procedure by correcting to first order the elastic constants of MgSiO$_3$-perovskite and MgSiO$_3$-post-perovskite, the major phases of the Earth's lower mantle. We show that this first order correction is quite satisfactory for obtaining the aggregated elastic averages of these minerals and their velocities in the lower mantle. This type of correction is also shown to be applicable to experimental measurements of elastic constants in situations where deviatoric stresses can develop, such as in diamond anvil cells.Comment: 4 figures, 1 table, submitted to Phys. Rev. B, July 200

Classification of Standard Model Particles in E6E_6 Orbifold Grand Unified Theories

We classify the standard model fermions, which originate from bulk fields of the $\bf{27}$ or $\bar{\bf{27}}$ representation after orbifold breaking, in $E_6$ grand unified theories on 5 or 6-dimensional space-time, under the condition that $q$, $e^c$ and $u^c$ survive as zero modes.Comment: 24 pages, typos corrected, to appear in IJMP

Magnetization pinning in conducting films demonstrated using broadband ferromagnetic resonance

The broadband microstrip ferromagnetic resonance technique has been applied for detection and characterization of a magnetic inhomogeneity in a film sample. In the case of a 100nm thick Permalloy film an additional magnetically depleted top sub-layer, practically unidentifiable by the conventional ferromagnetic resonance setup, has been detected and characterized. These results have been confirmed by Brillouin light scattering spectroscopy revealing the fact that the optical properties of the additional sub-layer do not differ much from those of the bulk of the film. Subsequent characterization of a large number of other presumably single-layer films with thicknesses in the range 30-100nm using the same ferromagnetic resonance technique also revealed the same effect