July 2006 arXiv papers — page 30

Dan Edidin, Christopher A. Francisco

In this note we use Bott-Borel-Weil theory to compute cohomology of interesting vector bundles on sequences of Grassmanians.

Alan L. Carey, Bai-Ling Wang

We establish the Thom isomorphism in twisted K-theory for any real vector bundle and develop the push-forward map in twisted K-theory for any differentiable proper map $f: X\to Y$ (not necessarily K-oriented). The push-forward map generalizes the push-forward map in ordinary K-theory for any $K$-oriented differentiable proper map and the Atiyah-Singer index

Yildiray Ozan

Let $M$ be a closed connected smooth manifold and $G=\textmd{Diff}_0(M)$ denote the connected component of the diffeomorphism group of $M$ containing the identity. The natural action of $G$ on $M$ induces the trace homomorphism on homology. We show that the image of trace homomorphism is annihilated by the subalgebra of the cohomology ring of $M$, generated

Jean-Rene Chazottes, Frank Redig, Evgeny Verbitskiy

We prove an exponential approximation for the law of approximate occurrence of typical patterns for a class of Gibssian sources on the lattice $\mathbb{Z}^d$, $d\ge2$. From this result, we deduce a law of large numbers and a large deviation result for the waiting time of distorted patterns.

Ben Morris

We obtain a tight bound of $O(L^2\log k)$ for the mixing time of the exclusion process in $\mathbf{Z}^d/L\mathbf{Z}^d$ with $k\leq{1/2}L^d$ particles. Previously the best bound, based on the log Sobolev constant determined by Yau, was not tight for small $k$. When dependence on the dimension $d$ is considered, our bounds are an improvement for all $k$. We al

V. Gayral, B. Iochum, D. V. Vassilevich

The heat trace asymptotics on the noncommutative torus, where generalized Laplacians are made out of left and right regular representations, is fully determined. It turns out that this question is very sensitive to the number-theoretical aspect of the deformation parameters. The central condition we use is of a Diophantine type. More generally, the importanc

E. Dudas, Y. Mambrini

We study the effect of anomalous U(1) gauge groups in string theory compactification with fluxes. We find that, in a gauge invariant formulation, consistent AdS vacua appear breaking spontaneously supergravity. Non vanishing D-terms from the anomalous symmetry act as an uplifting potential and could allow for de Sitter vacua. However, we show that in this ca

Uri Jacob, Tsvi Piran

Lorentz Invariance Violation (LIV) arises in various quantum-gravity theories. As the typical energy for quantum gravity is the Planck mass, $M_{pl}$, LIV will, most likely, be manifested at very high energies that are not accessible on Earth in the foreseeable future. One has to turn to astronomical observations. Time of flight measurement from different as

Marco Contalbrigo, Alessandro Drago, Paolo Lenisa

Large double spin-asymmetries can be foreseen for Drell-Yan production in $p p$ scattering at JPARC energies. The sign of the asymmetries can be used to discriminate between different model calculations of sea quark distributions.

Ernest Ma

The radiative seesaw mechanism proposed recently is minimally extended to include supersymmetry in a specific model. Relevant related issues such as leptogenesis and dark matter are discussed.

R. Boughezal, M. Czakon, T. Schutzmeier

Recent applications of single-scale four-loop tadpoles are briefly reviewed. An algorithm for the evaluation of current correlators based on differential equations is described and applied to obtain high moments of the vacuum polarization function at O(alphas^2) as a preparation of O(alphas^3) calculations.

Joseph P. Conlon

I describe how under favourable circumstances the invisible axion may manifest its existence at the LHC through the sparticle spectrum; in particular through a gluino \sim \ln (M_P/m_{3/2}) times heavier than other gauginos.

Michael Maziashvili

Quantum fluctuations of gravitational field with respect to the ADD braneworld background turns out to be large enough spoiling the TeV scale physics as well. In view of this observation it becomes important to look for some protecting mechanism. The most natural such mechanism in the case of braneworld model with compactified extra dimensions can be the sha

A. H. Mueller, A. I. Shoshi, S. M. H. Wong

We investigate Kolmogorov wave turbulence in QCD or, in other words, we calculate the spectrum of gluons as a function of time, f_k(t), in the presence of a source which feeds in energy density in the infrared region at a constant rate. We find an early, an intermediate and a late time form for the gluon spectrum. Wave turbulence in QCD turns out to be somew

V. A. Khoze, M. G. Ryskin, W. J. Stirling

Central exclusive Higgs boson production, pp -> p + H + p, at the LHC and s-channel resonant Higgs production in the photon-collider option of the ILC can provide a very important contribution to the comprehensive study of the Higgs sector. Especially attractive is the b bbar Higgs decay mode, which for certain MSSM scenarios may become the discovery channel

B. Pire, L. Szymanowski

The generalized Bjorken regime of exclusive reactions opens new ways to explore the hadron structure. We shortly review the present status of this domain where generalized parton distributions, generalized distribution amplitudes and transition distribution amplitudes describe various aspects of confinement physics.

Xuelei Wang, Yaobei Liu, Jihong Chen, Hua Yang

The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs model, we study the process $e^{+}e^{-}\to e^{+}e^{-}H$ at the ILC and calculate the correction of the littlest Higgs model to the cross section of this process. The results show that, in the favorable parameter spaces preferred by the

J. P. Lansberg, B. Pire, L. Szymanowski

We analyse deeply-virtual Compton scattering on a proton target, gamma* P -> P' gamma in the backward region and in the scaling regime. We define the transition distribution amplitudes which describe the proton to photon transition. Model-independent predictions are given to test this description, for current or planned experiments at JLab or by Hermes.

Barry R. Holstein

A previous evaluation of one-photon loop corrections to the energy-momentum tensor has been extended to particles with unit spin and speculations are presented concerning general properties of such forms.

Cathal Boogerd, Leon Moonen

Static software checking tools are useful as an additional automated software inspection step that can easily be integrated in the development cycle and assist in creating secure, reliable and high quality code. However, an often quoted disadvantage of these tools is that they generate an overly large number of warnings, including many false positives due to

Yoann Dieudonne, Ouiddad Labbani-Igbida, Franck Petit

In this paper we prove the conjecture of Défago & Konagaya. Furthermore, we describe a deterministic protocol for forming a regular n-gon in finite time.

Vlady Ravelomanana, Alphonse Laza Rijamame

Denote by an $\ell$-component a connected $b$-uniform hypergraph with $k$ edges and $k(b-1) - \ell$ vertices. We prove that the expected number of creations of $\ell$-component during a random hypergraph process tends to 1 as $\ell$ and $b$ tend to $\infty$ with the total number of vertices $n$ such that $\ell = o(\sqrt[3]{\frac{n}{b}})$. Under the same cond

Tom Ridge

We formalise and mechanise a construtive, proof theoretic proof of Craig's Interpolation Theorem in Isabelle/HOL. We give all the definitions and lemma statements both formally and informally. We also transcribe informally the formal proofs. We detail the main features of our mechanisation, such as the formalisation of binding for first order formulae. W

Vlady Ravelomanana, the Projet PAI Amadeus Collaboration

We study the sizes of connected components according to their excesses during a random graph process built with $n$ vertices. The considered model is the continuous one defined in Janson 2000. An ${\ell}$-component is a connected component with ${\ell}$ edges more than vertices. $\ell$ is also called the \textit{excess} of such component. As our main result,

Sylviane Schwer

The formalizations of periods of time inside a linear model of Time are usually based on the notion of intervals, that may contain or may not their endpoints. This is not enought when the periods are written in terms of coarse granularities with respect to the event taken into account. For instance, how to express the inter-war period in terms of a {\em year

T. Jungk, A. Hoffmann, E. Soergel

Ferroelectric domain imaging with piezoresponse force microscopy (PFM) relies on the converse piezoelectric effect: a voltage applied to the sample leads to mechanical deformations. In case of PFM one electrode is realized by the tip, therefore generating a strongly inhomogeneous electric field distribution inside the sample which reaches values up to $10^8

C. -H. Zhang

The single-particle and interaction effects on the cohesion, electronic transport, and some magnetic properties of metallic nanocylinders have been studied at finite voltages by using a generalized mean-field electron model. The electron-electron interactions are treated in the self-consistent Hartree approximation. Our results show the single-particle effec

Victor Kurasov

The ways to construct solution of the evolution equation in the homogeneous free molecular condensation under dynamic conditions are presented in parametric form.

Young L. Kim, Prabhakar Pradhan, Min H. Kim, Vadim Backman

We experimentally study the propagation of circularly polarized light in the sub-diffusion regime by exploiting enhanced backscattering (EBS, also known as coherent backscattering) of light under low spatial coherence illumination. We demonstrate for the first time that circular polarization memory effect exists in EBS over a large range of scatterers' s

D. Coslovich, G. Pastore

We numerically study the interplay between heterogeneous dynamics and properties of negatively curved regions of the potential energy surface in a model glassy system. We find that the unstable modes of saddles and quasi-saddles undergo a localization transition close to the Mode-Coupling critical temperature. We also find evidence of a positive spatial corr

Frank Raischel, Ferenc Kun, Hans J. Herrmann

We study the failure properties of fiber bundles with a finite lower cutoff of the strength disorder varying the range of interaction between the limiting cases of completely global and completely local load sharing. Computer simulations revealed that at any range of load redistribution there exists a critical cutoff strength where the macroscopic response o

P. I. Arseyev, N. S. Maslova

We analyze generation of phonons in tunneling structures with two electron states coupled by electron-phonon interaction. The conditions of strong vibration excitations are determined and dependence of non-equilibrium phonon occupation numbers on the applied bias is found. For high vibration excitation levels self consistent theory for the tunneling transpor

G. A. Baramidze, G. A. Kharadze

The magnetic field dependence of the $A\to B$ transition temperature $T_{AB}$ in the superfluid $^3He$ is reconsidered in order to take into account the linear-in-field contribution beyond the approximation used in Ref.[7]. In the high field region, where the quadratic-in-field contribution prevails, the well known answer is restored. On the other hand,it is

V. A. Kulbachinskii, I. S. Vasil'evskii, R. A. Lunin, G. Galistu

Shallow GaAs/InGaAs/GaAs quantum well structures with and without a three monolayer thick AlAs central barrier have been investigated for different well widths and Si doping levels. The transport parameters are determined by resistivity measurements in the temperature range 4-300 K and magnetotransport in magnetic fields up to 12 T. The (subband) carrier con

Sobhendu K. Ghatak

A disordered alloy Ap B1-p where both A and B represent the magnetic atoms with respective spin SA =1/2 and SB =1 and whose magnetic interaction can be described through Ising Hamiltonian is treated using the cluster-variational method. In this method it is assumed that the system is built out of building block which is embedded in an effective field. Taking

C. H. Schunck, M. W. Zwierlein, A. Schirotzek, W. Ketterle

We study the expansion of a rotating, superfluid Fermi gas. The presence and absence of vortices in the rotating gas is used to distinguish superfluid and normal parts of the expanding cloud. We find that the superfluid pairs survive during the expansion until the density decreases below a critical value. Our observation of superfluid flow at this point exte

I. S. Beloborodov, Ya. V. Fominov, A. V. Lopatin, V. M. Vinokur

We analyze the possibility of the formation of a magnetic-field-induced insulating state in a two-dimensional granular superconductor with relatively strong intergranular coupling and show that such a state appears in a model with spatial variations of the single-grain critical magnetic field. This model describes realistic granular samples with the dispersi

Michael Hinczewski, A. Nihat Berker

The anisotropic d=3 tJ model is studied by renormalization-group theory, yielding the evolution of the system as interplane coupling is varied from the isotropic three-dimensional to quasi-two-dimensional regimes. Finite-temperature phase diagrams, chemical potential shifts, and in-plane and interplane kinetic energies and antiferromagnetic correlations are

F. Douglas Swesty, Eric S. Myra

It is now generally agreed that multidimensional, multigroup, radiation hydrodynamics is an indispensable element of any realistic model of stellar-core collapse, core-collapse supernovae, and protoneutron star instabilities. We have developed a new, two-dimensional, multigroup algorithm that can model neutrino-radiation-hydrodynamic flows in core-collapse s

Michael R. Corbin, William D. Vacca, Roberto Cid Fernandes, John E. Hibbard

We present deep Hubble Space Telescope Advanced Camera for Surveys / High Resolution Channel U, narrow-V, and I images of nine &#34;ultracompact&#34; blue dwarf galaxies (UCBDs) selected from the Sloan Digital Sky Survey. We define UCBDs as local (z < 0.01) star-forming galaxies having angular diameters < 6&#34; and physical sizes < 1 kpc. They are also amon

Avery Broderick, Abraham Loeb

Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the supermassive black hole in the Galactic center casts upon background emission. However, more exciting is the prospect of observin

D. A. Schwartz, H. L. Marshall, J. E. J. Lovell, D. W. Murphy

This letter reports rich X-ray jet structures found in the Chandra observation of PKS 1055+201. In addition to an X-ray jet coincident with the radio jet we detect a region of extended X-ray emission surrounding the jet as far from the core as the radio hotspot to the North, and a similar extended X-ray region along the presumed path of the unseen counterjet

A. Georgakakis, K. Nandra, E. S. Laird, M. C. Cooper

We explore the environment of z~1 AGN using a sample of 53 spectroscopically identified X-ray sources in the All-wavelength Extended Groth strip International Survey. We quantify the local density in the vicinity of an X-ray source by measuring the projected surface density of spectroscopically identified optical galaxies within a radius defined by the 3rd n

Hector J. Martinez, Ana L. O&#39;Mill, Diego G. Lambas

We analyse $u-r$ colour distributions for several samples of galaxies in groups drawn from the Fourth Data Release of the Sloan Digital Sky Survey. For all luminosity ranges and environments considered the colour distributions are well described by the sum of two Gaussian functions. We find that the fraction of galaxies in the red sequence is an increasing f

K. Nandra, A. Georgakakis, C. N. A. Willmer, M. C. Cooper

We discuss the relationship between rest-frame color and optical luminosity for X-ray sources in the range 0.6<z<1.4 selected from the Chandra survey of the Extended Groth Strip (EGS). These objects are almost exclusively active galactic nuclei (AGN). While there are a few luminous QSOs, most are relatively weak or obscured AGN whose optical colors should be

W. K. M. Rice, G. Lodato, J. E. Pringle, P. J. Armitage

An unsolved issue in the standard core accretion model for gaseous planet formation is how kilometre-sized planetesimals form from, initially, micron-sized dust grains. Solid growth beyond metre sizes can be difficult both because the sticking efficiency becomes very small, and because these particles should rapidly migrate into the central star. We consider

J. Wagg, D. J. Wilner, R. Neri, D. Downes

We present a detection of [CI] line emission in the lensed quasar APM 08279+5255 at z=3.91 using the IRAM Plateau de Bure interferometer. The [CI] line velocity and width are similar to the values of previously detected high-J CO and HCN lines in this source, suggesting that the emission from all of these species arises from the same region. The apparent lum

D. O&#39;Donoghue, D. A. H. Buckley, L. A. Balona, D. Bester

We describe briefly the properties of the recently completed Southern African Large Telescope (SALT), along with its first light imager SALTICAM. Using this instrument, we present 4.3 hr of high speed unfiltered photometric observations of the eclipsing polar SDSSJ015543.40+002807.2 with time resolution as short as 112 ms, the highest quality observations of

J. L. Hinz, K. Misselt, M. J. Rieke, G. H. Rieke

We present Spitzer Space Telescope images of the isolated dwarf galaxy UGC 10445. The galaxy is detected at all photometric bands (3.6-160um) as well as in the Multiband Imaging Photometer for Spitzer (MIPS) spectral energy distribution mode (55-95um). We derive a star formation rate of 0.25 M_sun/yr based on H-alpha and infrared flux densities. There is ove

T. Morel, K. Butler, C. Aerts, C. Neiner

We present the results of a detailed NLTE abundance study of nine beta Cephei stars, all of them being prime targets for theoretical modelling: gamma Peg, delta Cet, nu Eri, beta CMa, xi1 CMa, V836 Cen, V2052 Oph, beta Cep and DD (12) Lac. The following chemical elements are considered: He, C, N, O, Mg, Al, Si, S and Fe. Our abundance analysis is based on a

J. A. L. Aguerri, N. Castro-Rodriguez, N. Napolitano, M. Arnaboldi

Compact groups are associations of a few galaxies in which the environment plays an important role in galaxy evolution. The low group velocity dispersion favors tidal interactions and mergers, which may bring stars from galaxies to the diffuse intragroup light. Numerical simulations of galaxy clusters in hierarchical cosmologies show that the amount of the d

L. P. L. Colombo, M. Gervasi

Recent data, including the three--year WMAP data, the full 2dF galaxy power spectrum and the first--year data of the Supernova Legacy Survey, are used to constrain model parameters in quintessence cosmologies. In particular, we discuss the inverse power--law (RP) and SUGRA potentials and compare parameter constraints with those for LCDM. Both potentials fit

Anwesh Mazumdar, Maryline Briquet, Maarten Desmet, Conny Aerts

We present the results of a detailed analysis of 452 ground-based high-resolution high S/N spectroscopic measurements spread over 4.5 years for beta Canis Majoris with the aim to determine the pulsational characteristics of this star, and to use them to derive seismic constraints on the stellar parameters. We determine pulsation frequencies in the SiIII 4553

G. H. Janssen, B. W. Stappers

We have analyzed 5.5 years of timing observations of 7 &#39;slowly&#39; rotating radio pulsars, made with the Westerbork Synthesis Radio Telescope. We present improved timing solutions and 30, mostly small, new glitches. Particularly interesting are our results on PSR J1814-1744, which is one of the pulsars with similar rotation parameters and magnetic field

Yann Clénet, Markus Kasper, Eric Gendron, Thierry Fusco

Adaptive optics (AO) allows one to derive the point spread function (PSF) simultaneously to the science image, which is a major advantage in post-processing tasks such as astrometry/photometry or deconvolution. Based on the algorithm of \citet{veran97}, PSF reconstruction has been developed for four different AO systems so far: PUEO, ALFA, Lick-AO and Altair

P. Charlot, D. C. Gabuzda, H. Sol, B. Degrange

The TeV-emitting BL Lac object Mkn 421 was observed with very long baseline interferometry (VLBI) at three closely-spaced epochs one-month apart in March-April 1998. The source was also monitored at very-high gamma-ray energies (TeV measurements) during the same period in an attempt to search for correlations between TeV variability and the evolution of the

Amir H. Fatollahi, Maryam Hajirahimi

Including loop corrections, black-body radiation in noncommutative space is anisotropic. A direct implication of possible space noncommutativity on the Cosmic Microwave Background map is argued.

Tarun Souradeep

Measurements of CMB anisotropy and, more recently, polarization have played a very important role allowing precise determination of various parameters of the `standard&#39; cosmological model. The expectation of the paradigm of inflation and the generic prediction of the simplest realization of inflationary scenario in the early universe have also been estab

M. Maturi, M. Schirmer, M. Meneghetti, M. Bartelmann

We apply the linear filter for the weak-lensing signal of dark-matter halos developed in Maturi et al. (2005) to the cosmic-shear data extracted from the Garching-Bonn-Deep-Survey (GaBoDS). We wish to search for dark-matter halos through weak-lensing signatures which are significantly above the random and systematic noise level caused by intervening large-sc

D. Ilic, L. C. Popovic, E. Bon, E. G. Mediavilla

In this work we study the physical and kinematical properties of the emission line region of Seyfert 1.5 galaxy Mrk 817 using three sets of observations, among which are high-resolution spectra obtained with the Isaac Newton Telescope on Canary Islands. We find that in Mrk 817 the Narrow (NEL) and Broad Emission Lines (BEL) are very complex, indicating that

S. Orlando, F. Bocchino, G. Peres, F. Reale

AIMS. We study and discuss the time-dependent X-ray emission predicted by hydrodynamic modeling of the interaction of a SNR shock wave with an interstellar gas cloud. The scope includes: 1) to study the correspondence between modeled and X-ray emitting structures, 2) to explore two different physical regimes in which either thermal conduction or radiative co

N. La Palombara, R. P. Mignani, E. Hatziminaoglou, M. Schirmer

The limited angular resolution of gamma-ray telescopes prevents a direct identification of the majority of sources detected so far. This is particularly true for the low latitude, probably galactic, ones only 10 % of which has been identified. Most counterparts of the identified low-latitude gamma-ray sources are Isolated Neutron Stars (INS), both radio-loud

M. B. Bogdanov, A. M. Cherepashchuk

We carried out numerical experiments on the evaluation of the possibilities of obtaining the information about brightness distributions for the components of eclipsing variables from the data of high-precision photometry expected for planned satellites COROT and Kepler. We examined a simple model of the eclipsing binary with the spherical components on circu

Francesco Vissani

We describe a simple procedure to estimate the high-energy neutrino flux from the observed gamma-ray spectra of galactic cosmic ray sources that are transparent to their gamma radiation. We evaluate in this way the neutrino flux from the supernova remnant RX J1713.7-3946, whose very high-energy gamma-ray spectrum (assumed to be of hadronic origin) is not a p

Tatiana V. Shabanova

The pulsar B1822-09 (J1825-0935) experienced a series of five unusual slow glitches over the 1995-2004 interval. The results of further study of this unusual glitch phenomenon are presented. It is also reported the detection a new glitch of typical signature that occurred in the pulsar period in 2006 January.

Mathieu de Naurois

Three different analysis techniques for Atmospheric Imaging System are presented. The classical Hillas parameters based technique is shown to be robust and efficient, but more elaborate techniques can improve the sensitivity of the analysis. A comparison of the different analysis techniques shows that they use different information for gamma-hadron separatio

Stuart Wyithe, Abraham Loeb

The HII regions around quasars and galaxies at redshifts beyond the epoch of reionisation will provide prime targets for upcoming 21cm campaigns using a new generation of low-frequency radio observatories. Here we show that the boundaries of these HII regions will not be sharp. Rather, the clustering of sources near massive galaxies results in a neutral frac

J. E. Chiar, A. J. Adamson, D. C. B. Whittet, A. Chrysostomou

Aliphatic hydrocarbons exhibit an absorption feature at 3.4 micron observed toward sources that sample diffuse regions of the interstellar medium. The absorbers responsible for this feature are assumed to reside in some component of interstellar dust, but the physical nature of the particles (size, shape, structure, etc.) is uncertain. Observations of inters

Alexander Friedland, Andrei Gruzinov

Convection that develops behind the shock front during the first second of a core-collapse supernova explosion is believed to play a crucial role in the explosion mechanism. We demonstrate that the resulting turbulent density fluctuations may be directly observable in the neutrino signal starting at t>~ 3-4 s after the onset of the explosion. The effect come

P. Saha, J. Coles, A. V. Maccio&#39;, L. L. R. Williams

We present a simultaneous analysis of 10 galaxy lenses having time-delay measurements. For each lens we derive a detailed free-form mass map, with uncertainties, and with the additional requirement of a shared value of the Hubble parameter across all the lenses. We test the prior involved in the lens reconstruction against a galaxy-formation simulation. Assu

L. A. Moustakas, P. J. Marshall, J. A. Newman, A. L. Coil

We report on the results of a visual search for galaxy-scale strong gravitational lenses over 650 arcmin^2 of HST/ACS imaging in the DEEP2-EGS field. In addition to a previously-known Einstein Cross (the &#34;Cross,&#34; HST J141735+52264, with z_lens=0.8106 and a published z_source=3.40), we identify two new strong galaxy-galaxy lenses with multiple extende

Chaohong Lee, Tristram J. Alexander, Yuri S. Kivshar

We consider nonlinear boson states with a nontrivial phase structure in the three-site Bose-Hubbard ring, {\em quantum discrete vortices} (or {\em q-vortices}), and study their &#34;melting&#34; under the action of quantum fluctuations. We calculate the spatial correlations in the ground states to show the superfluid-insulator crossover and analyze the fidel

J. D. Gibbon, D. D. Holm

Experimentalists now measure intense rotations of Lagrangian particles in turbulent flows by tracking their trajectories and Lagrangian-average velocity gradients at high Reynolds numbers. This paper formulates the dynamics of an orthonormal frame attached to each Lagrangian fluid particle undergoing three-axis rotations, by using quaternions in combination

A. Christian Silva, Richard E. Prange

We introduce the concept of virtual volatility. This simple but new measure shows how to quantify the uncertainty in the forecast of the drift component of a random walk. The virtual volatility also is a useful tool in understanding the stochastic process for a given portfolio. In particular, and as an example, we were able to identify mean reversion effect

Toufik Mansour, Matthias Schork, Simone Severini

Normally ordered forms of functions of boson operators are important in many contexts in particular concerning Quantum Field Theory and Quantum Optics. Beginning with the seminal work of Katriel [Lett. Nuovo Cimento, 10(13):565--567, 1974], in the last few years, normally ordered forms have been shown to have a rich combinatorial structure, mainly in virtue

Jonathan R. Pritchard, Steven R. Furlanetto

Many models of early structure formation predict a period of heating immediately preceding reionization, when X-rays raise the gas temperature above that of the cosmic microwave background. These X-rays are often assumed to heat the intergalactic medium (IGM) uniformly, but in reality they will heat the gas more strongly closer to the sources. We develop a f

Genya Takeda, Eric B. Ford, Alison Sills, Frederic A. Rasio

We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie Planet Search has obtained high-quality echelle spectra of over 1000 nearby stars taken with the Hamilton spectrograph at Lick Observatory, the HIRES spectrograph at Keck, and UCLES at the Anglo Australian O

P. Kanti, R. A. Konoplya, A. Zhidenko

This paper presents a comprehensive study of the fundamental quasinormal modes of all Standard Model fields propagating on a brane embedded in a higher-dimensional rotating black hole spacetime. The equations of motion for fields with spin $s=0, 1/2$ and 1 propagating in the induced-on-the-brane background are solved numerically, and the dependence of their

Santo Fortunato, Marc Barthelemy

Detecting community structure is fundamental to clarify the link between structure and function in complex networks and is used for practical applications in many disciplines. A successful method relies on the optimization of a quantity called modularity [Newman and Girvan, Phys. Rev. E 69, 026113 (2004)], which is a quality index of a partition of a network

T. A. Sedrakyan, E. G. Mishchenko, M. E. Raikh

We study theoretically the charge separation in a planar array of semiconducting nanotubes (NTs) of length, 2h, placed in external electric field, F, parallel to their axes. By employing the conformal mapping, we find analytically the exact distribution of the induced charge density for arbitrary ratio of the gap, E_g, and the voltage drop, eFh, across the N

Jan O. Haerter, Michael R. Peterson, B. Sriram Shastry

Within the t-J model we study several experimentally accessible properties of the 2D-triangular lattice system Na$_x$CoO$_2$, using a numerically exact canonical ensemble study of 12 to 18 site triangular toroidal clusters as well as the icosahedron. Focusing on the doping regime of $x\sim0.7$, we study the temperature dependent chemical potential, specific

Emanuele Berti, Sai Iyer, Clifford M. Will

Using a post-Newtonian diagnostic tool developed by Mora and Will, we examine numerically generated quasiequilibrium initial data sets that have been used in recently successful numerical evolutions of binary black holes through plunge, merger and ringdown. We show that a small but significant orbital eccentricity is required to match post-Newtonian and quas

Alexandre F. da Fonseca, C. P. Malta, D. S. Galvao

Helical amorphous nanosprings have attracted particular interest due to their special mechanical properties. In this work we present a simple model, within the framework of the Kirchhoff rod model, for investigating the structural properties of nanosprings having asymmetric cross section. We have derived expressions that can be used to obtain the Young&#39;s

Matias Aiello, Gabriel Bengochea, Rafael Ferraro

We show exact solutions of Born-Infeld theory for electromagnetic plane waves propagating in the presence of static background fields. The non-linear character of Born-Infeld equations generates an interaction between background and wave that changes the speed of propagation and adds a longitudinal component to the wave. As a consequence, in a magnetic backg

Pascal Barla, Simon Breslav, Lee Markosian, Joëlle Thollot

We describe a system that lets a designer interactively draw patterns of strokes in the picture plane, then guide the synthesis of similar patterns over new picture regions. Synthesis is based on an initial user-assisted analysis phase in which the system recognizes distinct types of strokes (hatching and stippling) and organizes them according to perceptual

Mohsen Bayati, Chandra Nair

In this paper we rigorously prove the validity of the cavity method for the problem of counting the number of matchings in graphs with large girth. Cavity method is an important heuristic developed by statistical physicists that has lead to the development of faster distributed algorithms for problems in various combinatorial optimization problems. The valid

Pierre Parrend, Stéphane Frénot

Last years have seen a dramatic increase in the use of component platforms, not only in classical application servers, but also more and more in the domain of Embedded Systems. The OSGi(tm) platform is one of these platforms dedicated to lightweight execution environments, and one of the most prominent. However, new platforms also imply new security flaws, a

M. B. Gay Ducati, W. K. Sauter

In this work, we perform a comparison of the employ of distinct gluon propagators with the experimental data in diffractive processes, $pp$ elastic scattering and light meson photo-production. The gluon propagators are calculated through non-perturbative methods, being justified their use in this class of events, due to the smallness of the momentum transfer

Yoshitaka Hatta

In this work we extend the JIMWLK formalism to the two-source problem. The S-matrix for the forward scattering can be written in a double functional integral representation which involves the usual functional integral for the gluon field and the spin path integral for the external color sources. Modifications needed in the light-cone gauge are discussed. Usi

Máté Matolcsi, Júlia Réffy, Ferenc Szöllősi

Applications in quantum information theory and quantum tomography have raised current interest in complex Hadamard matrices. In this note we investigate the connection between tiling Abelian groups and constructions of complex Hadamard matrices. First, we recover a recent very general construction of complex Hadamard matrices due to Dita via a natural tiling

W. Kilian, J. Reuter, T. Robens

We present a Monte-Carlo event generator for simulating chargino pair-production at the International Linear Collider (ILC) at next-to-leading order in the electroweak couplings. By properly resumming photons in the soft and collinear regions, we avoid negative event weights, so the program can simulate physical (unweighted) event samples. Photons are explic

R. Sekhar Chivukula, Baradhwaj Coleppa, Stefano Di Chiara, Hong-Jian He

We analyze the spectrum and properties of a highly-deconstructed Higgsless model with only three sites. Such a model contains sufficient complexity to incorporate interesting physics issues related to fermion masses and electroweak observables, yet remains simple enough that it could be encoded in a Matrix Element Generator program for use with Monte Carlo s

P. Tisserand, L. Le Guillou, C. Afonso, J. N. Albert

The EROS-2 project was designed to test the hypothesis that massive compact halo objects (the so-called ``machos&#39;&#39;) could be a major component of the dark matter halo of the Milky Way galaxy. To this end, EROS-2 monitored over 6.7 years $33\times10^6$ stars in the Magellanic clouds for microlensing events caused by such objects. In this work, we use

Adrian Vasiu

Let $k$ be an algebraically closed field of characteristic $p>0$. Let $D$ be a $p$-divisible group over $k$. Let $n_D$ be the smallest non-negative integer for which the following statement holds: if $C$ is a $p$-divisible group over $k$ of the same codimension and dimension as $D$ and such that $C[p^{n_D}]$ is isomorphic to $D[p^{n_D}]$, then $C$ is isomorp

W. Sacks, T. Cren, D. Roditchev, B. Doucot

We previously introduced [T. Cren et al., Europhys. Lett. 52, 203 (2000)] an energy-dependant gap function, $Δ(E)$, that fits the unusual shape of the quasiparticle (QP) spectrum for both BiSrCaCuO and YBaCuO. A simple anti-resonance in $Δ(E)$ accounts for the pronounced QP peaks in the density of states, at an energy $Δ_p$, and the dip feature at a higher e

V. P. Goncalves, M. V. T. Machado

In this work we estimate the heavy quark production in the interaction of ultra high energy cosmic rays in the atmosphere, considering that the primary cosmic ray is a proton or a photon. At these energies the saturation momentum Q_{sat}^2 stays above the hard scale μ_c^2=4m_c^2, implying charm production probing the saturation regime. In particular, we show

Michael Aizenman, Simone Warzel

For operators with homogeneous disorder, it is generally expected that there is a relation between the spectral characteristics of a random operator in the infinite setup and the distribution of the energy gaps in its finite volume versions, in corresponding energy ranges. Whereas pure point spectrum of the infinite operator goes along with Poisson level sta

Marcela Carena, Eduardo Ponton, Jose Santiago, Carlos E. M. Wagner

We consider Randall-Sundrum scenarios based on SU(2)_L x SU(2)_R and a discrete parity exchanging L with R. The custodial and parity symmetries can be used to make the tree level contribution to the T parameter and the anomalous couplings of the bottom quark to the Z very small. We show that the resulting quantum numbers typically induce a negative T paramet

Hugo Garcia-Compean, Carlos Soto-Campos

We discuss some possible implications of a two-dimensional toy model for black hole evaporation in noncommutative field theory. While the noncommutativity we consider does not affect gravity, it can play an important role in the dynamics of massless and Hermitian scalar fields in the event horizon of a Schwarzschild black hole. We find that noncommutativity

A. Ogawa, M. Grosse-Perdekamp, R. Seidl, K. Hasuko

The measurement of the so far unknown chiral-odd quark transverse spin distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in pp collisions at RHIC has an additional chiral-odd fragmentation function appearing in the cross section. These chiral-odd fragmentation functions (FF) can for example be the so-called Collins FF or the Interfe