June 2009 arXiv papers — page 50

Giuseppe Carleo, Saverio Moroni, Stefano Baroni

The lattice dynamics of hcp crystalline 4He is studied at zero temperature and for two different densities (near and far from melting), using a ground-state path-integral quantum Monte Carlo technique. The complete phonon dispersion is obtained, with particular attention to the separation of optic and acoustic branches and to the identification of transverse

Laurent Veron

If $Ω$ is a bounded domain in $\mathbb R^N$ and $f$ a continuous increasing function satisfying a super linear growth condition at infinity, we study the existence and uniqueness of solutions for the problem (P): $\partial_tu-Δu+f(u)=0$ in $Q_\infty^Ω:=Ω\times (0,\infty)$, $u=\infty$ on the parabolic boundary $\partial_{p}Q$. We prove that in most cases, the

Y. Sobouti, A. Hasani Zonoozi, H. Haghi

Rotation curves of spiral galaxies \emph{i}) fall off much less steeply than the Keplerian curves do, and \emph{ii}) have asymptotic speeds almost proportional to the fourth root of the mass of the galaxy, the Tully-Fisher relation. These features alone are sufficient for assigning a dark companion to the galaxy in an unambiguous way. In regions outside a sp

Alan Heavens

In these lectures I cover a number of topics in cosmological data analysis. I concentrate on general techniques which are common in cosmology, or techniques which have been developed in a cosmological context. In fact they have very general applicability, for problems in which the data are interpreted in the context of a theoretical model, and thus lend them

Jinshu Huang, Gongru Lu, Xuelei Wang

We have calculated the cross section of the process e^+e^- \to γγ\to b\bar{b} in the littlest Higgs model with T parity (LHT). We find that, for the favorable parameters, the total cross section σ(e^+e^- \to γγ\to b\bar{b}) is sensitive to the breaking scale f, mixing parameter x_L, the masses of the mirror quarks m_{Hi}, and the relative correction of the L

Victor Kalvin

We develop the complex scaling method for the Dirichlet Laplacian in a domain with asymptotically cylindrical end. We define resonances as discrete eigenvalues of non-selfadjoint operators, obtained as deformations of the selfadjoint Dirichlet Laplacian $Δ$ by means of the complex scaling. The resonances are identified with the poles of the resolvent matrix

Jan Moser

The elementary geometric properties of the Jacob's ladders \cite{7} lead to a class of new formulae for short parts of the Hardy-Littlewood integral. This class of formulae cannot be obtained by methods of Balasubramanian, Heath-Brown and Ivic.

Tong Chern

We studied the quantum dynamics of six dimensional $\mathcal{N}=(2, 0)$ superconformal field theory (the QNG theory). We developed the spinor technique for six-dimensional quantum field theories. By combining this technique with the canonical quantization procedure, we can overcome the subtlety of the chiral nature of $\mathcal{N}=(2, 0)$ free tensor multipl

David Kyed

We prove that the zeroth L^2-Betti number of a compact quantum group vanishes unless the underlying C*-algebra is finite dimensional and that the zeroth L^2-homology itself is non-trivial exactly when the quantum group is coamenable.

Alberto Elduque

The fine abelian group gradings on the simple classical Lie algebras (including D4) over algebraically closed fields of characteristic 0 are determined up to equivalence. This is achieved by assigning certain invariant to such gradings that involve central graded division algebras and suitable sesquilinear forms on free modules over them.

Leo P. Kadanoff

This paper looks at the early theory of phase transitions. It considers a group of related concepts derived from condensed matter and statistical physics. The key technical ideas here go under the names of "singularity", "order parameter", "mean field theory", and "variational method". In a less technical vein, the question he

Pierre Alquier, Mohamed Hebiri

We consider the linear regression problem, where the number $p$ of covariates is possibly larger than the number $n$ of observations $(x_{i},y_{i})_{i\leq i \leq n}$, under sparsity assumptions. On the one hand, several methods have been successfully proposed to perform this task, for example the LASSO or the Dantzig Selector. On the other hand, consider new

Tomohiro Matsuda

Using the cosmological perturbation theory in terms of the delta-N formalism, we find the simple formulation of the evolution of the curvature perturbation in generalized gravity theories. Compared with the standard gravity theory, a crucial difference appears in the end-boundary of the inflationary stage, which is due to the non-ideal form of the energy mom

Michael Hellus

In continuation of [1] we study associated primes of Matlis duals of local cohomology modules (MDLCM). We combine ideas from Helmut Zöschinger on coassociated primes of arbitrary modules with results from [1], [4], [5], [6] and obtain partial answers to questions which were left open in [1]. These partial answers give further support for conjecture $(*)$ fro

Christopher M. Ormerod, Nicholas S. Witte, Peter J. Forrester

We present a framework for the study of $q$-difference equations satisfied by $q$-semi-classical orthogonal systems. As an example, we identify the $q$-difference equation satisfied by a deformed version of the little $q$-Jacobi polynomials as a gauge transformation of a special case of the associated linear problem for $q$-$\mathrm{P}_{\mathrm{VI}}$. We obt

Boris F Samsonov

The necessary and sufficient conditions for minimization of the generalized rate error for discriminating among $N$ pure qubit states are reformulated in terms of Bloch vectors representing the states. For the direct optimization problem an algorithmic solution to these conditions is indicated. A solution to the inverse optimization problem is given. General

JongHae Keum, DongSeon Hwang

Montgomery-Yang problem predicts that every pseudofree differentiable circle action on the 5-dimensional sphere has at most 3 non-free orbits. Using a certain one-to-one correspondence, Kollár formulated the algebraic version of the Montgomery-Yang problem: every projective surface $S$ with the second Betti number $b_2(S) = 1$ and with quotient singularities

Debasish Das

Theoretical models suggest that the Quantum Chromo-Dynamics (QCD) phase diagram has a critical point demarcating the order of transition between the two phases: the hadron gas, in which the quarks are confined and the Quark-Gluon Plasma (QGP). The central goal of the experiments with relativistic heavy-ion collisions is to create and study such form of matte

Takeshi Chiba, Sourish Dutta, Robert J. Scherrer

We derive slow-roll conditions for thawing k-essence with a separable Lagrangian $p(X,ϕ)=F(X)V(ϕ)$. We examine the evolution of the equation of state parameter, $w$, as a function of the scale factor $a$, for the case where $w$ is close to -1. We find two distinct cases, corresponding to $X \approx 0$ and $F_X \approx 0$, respectively. For the case where $X\

Chuanzhong Li, Jingsong He, Ke Wu, Yi Cheng

In this paper we generalize the Sato theory to the extended bigraded Toda hierarchy (EBTH). We revise the definition of the Lax equations,give the Sato equations, wave operators, Hirota bilinear identities (HBI) and show the existence of $tau$ function $τ(t)$. Meanwhile we prove the validity of its Fay-like identities and Hirota bilinear equations (HBEs) in

R. M. Sambruna, J. N. Reeves, V. Braito, K. T. Lewis

We present XMM and Suzaku observations of the Broad-Line Radio Galaxy (BLRG) 3C390.3. The Fe Ka line has a width FWHM ~ 8,800 km/s, consistent within a factor two with the width of the double-peaked H_alpha line, suggesting an origin from the Broad Line Region. The data show for the first time a weak, broad bump extending from 5 to 7 keV. When fitted with a

Subhash Kak

This paper extends the treatment of single-neuron memories obtained by the B-matrix approach. The spreading of the activity within the network is determined by the network's proximity matrix which represents the separations amongst the neurons through the neural pathways.

J. I. Aranda, A. Cordero--Cid, F. Ramírez--Zavaleta, J. J. Toscano

The recently observed mass difference of the $D^0-\overline{D^0}$ mixing is used to predict the branching ratios of the rare top quark decays $t\to u\gamma$ and $t\to ug$ in a model independent way using the effective Lagrangian approach. It is found that $Br(t\to u\gamma)<4\times 10^{-4}$ and $Br(t\to ug)<2\times 10^{-3}$, which still may be within reach of

Maxim Yattselev

We study AAK as well as Pad\'e approximants to functions f, where f is a sum of a Cauchy transform of a complex measure \mu supported on a real interval included in (-1,1), whose Radon-Nikodym derivative with respect to the arcsine distribution on its support is Dini-continuous, non-vanishing and with and argument of bounded variation, and of a rational func

V. G. Lopez Neumann, Constantin Manoil

We find formulas for the birational maps from a Kummer surface K and its dual K^* to their common minimal desingularization S. We show how the nodes of K blow up. Then we give a description of the group of linear automorphisms of S.

Hans Fritz, Joachim Ankerhold

Motivated by experiments with current biased superconducting atomic point contacts the general problem of nonadiabatic transitions between adiabatic surfaces in presence of strong dissipation is studied. For a single channel device the supercurrent is determined by the diffusive motion of the superconducting phase difference on two Andreev levels. These surf

I. Di Marco, J. Minár, J. Braun, M. I. Katsnelson

We investigate the role of magnetic fluctuations in the spectral properties of paramagnetic gamma-Mn. Two methods are employed. The Local Density Approximation plus Dynamical Mean-Field Theory together with the numerically exact quantum Monte-Carlo solver is used as a reference for the spectral properties. Then the same scheme is used with the computationall

W. F. Koehl, M. H. Wong, C. Poblenz, B. Swenson

Electrically generated spin polarization is probed directly in bulk GaN using Kerr rotation spectroscopy. A series of n-type GaN epilayers are grown in the wurtzite phase both by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) with a variety of doping densities chosen to broadly modulate the transverse spin lifetime, T2*. The

Dimitra Karabali, V. P. Nair, Alexandr Yelnikov

We carry out further analysis of the Hamiltonian approach to Yang-Mills theory in 2+1 dimensions which helps to place the calculation of the vacuum wave function and the string tension in the context of a systematic expansion scheme. The solution of the Schrodinger equation is carried out recursively. The computation of correlators is re-expressed in terms o

H. Tsuchiya, T. Enoto, T. Torii, K. Nakazawa

During thunderstorms on 2008 September 20, a simultaneous detection of gamma rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 seconds, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung g

Jie Kong, Truell W. Hyde, Brandon Harris, Ke Qiao

Employing an attenuated oscillation method, the anisotropic interaction force between two vertically aligned dust particles located in the sheath of a complex plasma was measured experimentally based on a linear approximation to the interaction force. Experimental data shows that although both particles experience a repulsive interaction force, the upper par

M. Hilker

In the last decade, a new kind of stellar systems has been established that shows properties in between those of globular clusters (GCs) and early-type dwarf galaxies. These so-called ultra-compact dwarf galaxies (UCDs) have masses in the range 10^6 to 10^8 M_sun and half-light radii of 10-100 pc. The most massive UCDs known to date are predominantly metal-r

E. H. Hwang, S. Das Sarma

We derive the plasmon dispersion in doped double layer graphene (DLG), made of two parallel graphene mono-layers with carrier densities $n_1$ and $n_2$ respectively, and an inter-layer separation of $d$. The linear chiral gapless single particle energy dispersion of graphene leads to exotic DLG plasmon properties with several unexpected experimentally observ

Norio Narita

The discovery of transiting extrasolar planets has enabled us a number of interesting stduies. Transit photometry reveals the radius and the orbital inclination of transiting planets, and thereby we can learn the true mass and the density of respective planets by the combined information of radial velocity measurements. In addition, follow-up observations of

D. Stello, W. J. Chaplin, H. Bruntt, O. L. Creevey

For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination of stars o

Michael Goff

We prove upper bounds on the face numbers of simplicial complexes in terms on their girths, in analogy with the Moore bound from graph theory. Our definition of girth generalizes the usual definition for graphs.

Kate Ponto

The Lefschetz fixed point theorem and its converse have many generalizations. One of these generalizations is to endomorphisms of a space relative to a fixed subspace. In this paper we define relative Lefschetz numbers and Reidemeister traces using traces in bicategories with shadows. We use the functoriality of this trace to identify different forms of thes

Leo P. Kadanoff

This note starts from work done by Dai, Geary, and Kadanoff (Hui Dai, Zachary Geary, and Leo P. Kadanoff, H. Dai, Z. Geary and L. P. Kadanoff, Journal of Statistical Mechanics, P05012 (2009)) on exact eigenfunctions for Toeplitz operators. It builds methods for finding convergent expansions for eigenvectors and eigenvalues of large-n Toeplitz matrices, using

L. H. Rodriguez-Merino, D. Rosa-Gonzalez, Y. D. Mayya, L. Carrasco

The M82 galaxy has been the subject of several studies basically because it is relatively close to to the Milky Way and it displays a strong star formation activity. Using multi-band images of M82 we have determined the age and extinction of the stellar population located in regions with strong UV emission, these region are in the nucleus and the disk of M82

Y. Divakara Mayya, Luis Carrasco

For decades, the nuclear starburst has taken all the limelight in M82 with very little discussion on M82 as a galaxy. The situation is changing over the last decade, with the publication of some important results on the morphology and stellar content of its disk and halo. In this review, we discuss these recent findings in the framework of M82 as a galaxy. I

Jorge F. Mejias, Joaquin J. Torres

In this work we study the detection of weak stimuli by spiking neurons in the presence of certain level of noisy background neural activity. Our study has focused in the realistic assumption that the synapses in the network present activity-dependent processes, such as short-term synaptic depression and facilitation. Employing mean-field techniques as well a

Nestor Armesto, Leticia Cunqueiro, Carlos A. Salgado

RHIC experiments have established jet quenching as a fundamental tool in the study of hot matter in heavy-ion collisions. The energy reached is enough for high-pT inclusive particle studies and one- or two-particle correlations up to pT= 10-20 GeV. The corresponding data are successfully described by a formalism based on radiative energy losses. This formali

Freddy Delbaen, Ying Hu, Adrien Richou

In a previous work, P. Briand and Y. Hu proved the uniqueness among the solutions which admit every exponential moments. In this paper, we prove that uniqueness holds among solutions which admit some given exponential moments. These exponential moments are natural as they are given by the existence theorem. Thanks to this uniqueness result we can strengthen

Andrei Faraon, Arka Majumdar, Hyochul Kim, Pierre Petroff

The resonance frequency of an InAs quantum dot strongly coupled to a GaAs photonic crystal cavity was electrically controlled via quantum confined Stark effect. Stark shifts up to 0.3meV were achieved using a lateral Schottky electrode that created a local depletion region at the location of the quantum dot. We report switching of a probe laser coherently co

M. Munsch, A. Mosset, A. Auffèves, Signe Seidelin

The light emission rate of a single quantum dot can be drastically enhanced by embedding it in a resonant semiconductor microcavity. This phenomenon is known as the Purcell effect, and the coupling strength between emitter and cavity can be quantified by the Purcell factor. The most natural way for probing the Purcell effect is a time-resolved measurement. H

Philippe Balcou

A scheme for an X-ray free electron laser is proposed, based on a Raman process occurring during the interaction between a moderately relativistic bunch of free electrons, and twin intense short pulse lasers interfering to form a transverse standing wave along the electron trajectories. In the high intensity regime of the Kapitza-Dirac effect, the laser pond

Gregg Musiker, Ralf Schiffler, Lauren Williams

We give combinatorial formulas for the Laurent expansion of any cluster variable in any cluster algebra coming from a triangulated surface (with or without punctures), with respect to an arbitrary seed. Moreover, we work in the generality of principal coefficients. An immediate corollary of our formulas is a proof of the positivity conjecture of Fomin and Ze

J. Javier Brey, N. Khalil, M. J. Ruiz-Montero

The existence of two stationary solutions of the nonlinear Boltzmann equation for inelastic hard spheres or disks is investigated. They are restricted neither to weak dissipation nor to small gradients. The one-particle distribution functions are assumed to have an scaling property, namely that all the position dependence occurs through the density and the t

A. Amo, T. C. H. Liew, C. Adrados, E. Giacobino

Propagating, directionally dependent, polarized spin-currents are created in an anisotropic planar semiconductor microcavity, via Rayleigh scattering of optically injected polaritons in the optical spin Hall regime. The influence of anisotropy results in the suppression or enhancement of the pseudospin precession of polaritons scattered into different direct

M. J. Tannenbaum

Results from PHENIX at RHIC in p-p and Au+Au collisions are presented from the perspective of measurements in p-p collisions at the CERN ISR which serve as a basis for many of the techniques used. Notable results include the equality of the suppression of inclusive pi0 and direct electrons (from the decay of heavy quarks) in the range of transverse momentuum

Jing-Nuo Wu, Chih-Hsien Huang, Szu-Cheng Cheng, Wen-Feng Hsieh

Spontaneous emission (SE) from a two-level atom in a photonic crystal (PC) with anisotropic one-band model is investigated using the fractional calculus. Analytically solving the kinetic equation in terms of the fractional exponential function, the dynamical discrepancy of SE between the anisotropic and isotropic systems is discussed on the basis of differen

Dr. Friedwardt Winterberg

It is proposed to treat cancer by the combination of a strong magnetic field with intense ultrasound. At the low electrical conductivity of tissue the magnetic field is not frozen into the tissue, and oscillates against the tissue which is brought into rapid oscillation by the ultrasound. As a result, a rapidly oscillating electric field is induced in the ti

Mathieu Lewin, Robert Seiringer

We consider a system of trapped spinless bosons interacting with a repulsive potential and subject to rotation. In the limit of rapid rotation and small scattering length, we rigorously show that the ground state energy converges to that of a simplified model Hamiltonian with contact interaction projected onto the Lowest Landau Level. This effective Hamilton

Dr. Friedwardt Winterberg

Excluding speculations about future breakthrough discoveries in physics, it is shown that with what is at present known, and also what is technically feasible, manned space flight to the limits of the solar system and beyond deep into the Oort cloud is quite well possible. Using deuterium as the rocket fuel of choice, abundantly available on the comets of th

Kun Zheng, Husheng Li, Seddik M. Djouadi, Jun Wang

Spectrum sensing is essential in cognitive radio to enable dynamic spectrum access. In many scenarios, primary user signal must be detected reliably in low signal-to-noise ratio (SNR) regime under required sensing time. We propose to use stochastic resonance, a nonlinear filter having certain resonance frequency, to detect primary users when the SNR is very

G. Lodato, S. Nayakshin, A. R. King, J. E. Pringle

We compute the effect of an orbiting gas disc in promoting the coalescence of a central supermassive black hole binary. Unlike earlier studies, we consider a finite mass of gas with explicit time dependence: we do not assume that the gas necessarily adopts a steady state or a spatially constant accretion rate, i.e. that the merging black hole was somehow ins

A. N. Poddubny, L. Pilozzi, M. M. Voronov, E. L. Ivchenko

We have theoretically studied propagation of exciton-polaritons in deterministic aperiodic multiple-quantum-well structures, particularly, in the Fibonacci and Thue-Morse chains. The attention is concentrated on the structures tuned to the resonant Bragg condition with two-dimensional quantum-well exciton. The superradiant or photonic-quasicrystal regimes ar

S. S. Gabriyelyan

It is proved that any infinite Abelian group of infinite exponent admits a non-discrete reflexive group topology.

Ramzi May

Let $u\in C([0,T^{\ast}[;L^{n}(\mathbb{R}% ^{n})^{n})$ be a maximal solution of the Navier-Stokes equations. We prove that $u$ is $C^{\infty}$ on $]0,T^{\ast}[\times \mathbb{R}^{n}$ and there exists a constant $\varepsilon _{\ast}>0$, which depends only on $n,$ such that if $T^{\ast}$ is finite then, for all $ω\in S(\mathbb{R}% ^{n})^{n},$ we have $\overline

J. J. Henderson, C. Koo, P. L. Feng, E. del Barco

We present low temperature magnetometry measurements on a new Mn3 single-molecule magnet (SMM) in which the quantum tunneling of magnetization (QTM) displays clear evidence for quantum mechanical selection rules. A QTM resonance appearing only at elevated temperatures demonstrates tunneling between excited states with spin projections differing by a multiple

Sean M. Andrews, D. J. Wilner, A. M. Hughes, Chunhua Qi

We present a high angular resolution (0.3&#34; = 40 AU) SMA survey of the 870 micron thermal continuum emission from 9 of the brightest, and therefore most massive, circumstellar disks in the ~1 Myr-old Ophiuchus star-forming region. Using 2-D radiative transfer calculations, we simultaneously fit the observed continuum visibilities and broadband spectral en

Dong-Bang Tsai, Po-Wen Chen, Hsi-Sheng Goan

We demonstrate how gradient ascent pulse engineering optimal control methods can be implemented on donor electron spin qubits in Si semiconductors with an architecture complementary to the original Kane&#39;s proposal. We focus on the high-fidelity controlled-NOT (CNOT) gate and explicitly find its digitized control sequences by optimizing its fidelity over

Piotr Bania

Paper addresses the process of dynamic data flow analysis using virtual code integration (VCI), often refered to as dynamic binary rewriting. This article will try to demonstrate all of the techniques that were applied in the SpiderPig project. It will also discuss the main differences between the methods that were employed and those used in other available

Emanuele Congiu, Elie Matar, Lars E. Kristensen, Francois Dulieu

There has always been a great deal of interest in the formation of H2 as well as in the binding energy released upon its formation on the surface of dust grains. The present work aims at collecting experimental evidence for how the bond energy budget of H2 is distributed between the reaction site and the internal energy of the molecule. So far, the non-detec

A. S. Miroshnichenko, E. L. Chentsov, V. G. Klochkova, S. V. Zharikov

FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photomet

W. Selke, L. N. Shchur

The Binder cumulant at the phase transition of Ising models on square lattices with ferromagnetic couplings between nearest neighbors and with competing antiferromagnetic couplings between next--nearest neighbors, along only one diagonal, is determined using Monte Carlo techniques. In the phase diagram a disorder line occurs separating regions with monotonic

Yu. A. Fadeyev

In this study we consider the nonlinear radial oscillations exciting in LBV--stars with effective temperatures 1.5e4 K <= Teff <= 3e4 K, bolometric luminosities 1.2e6 L_odot <= L <= 1.9e6 L_odot and masses 35.7 M_odot <= M <= 49.1 M_odot. Hydrodynamic computations were carried out with initial conditions obtained from evolutionary sequences of population I s

Alexey Kokotov

Compact polyhedral surfaces (or, equivalently, compact Riemann surfaces with conformal flat conical metrics) of an arbitrary genus are considered. After giving a short self-contained survey of their basic spectral properties, we study the zeta-regularized determinant of the Laplacian as a functional on the moduli space of these surfaces. An explicit formula

Sebastian Bernhardsson, Luis Enrique Correa da Rocha, Petter Minnhagen

It is shown that a real novel shares many characteristic features with a null model in which the words are randomly distributed throughout the text. Such a common feature is a certain translational invariance of the text. Another is that the functional form of the word-frequency distribution of a novel depends on the length of the text in the same way as the

J Sadeghi, M R Setare, A Banijamali

In this paper we show that power-law inflation can be realized in non-minimal gravitational coupling of electromagnetic field with a general function of Gauss-Bonnet invariant. Such a non-minimal coupling may appear due to quantum corrections. We also consider modified Maxwell-$F(G)$ gravity in which non-minimal coupling between electromagnetic field and $f(

A. Aparicio, S. L. Hidalgo

IAC-pop is a code designed to solve the star formation history (SFH) of a complex stellar population system, like a galaxy, from the analysis of the color-magnitude diagram (CMD). It uses a genetic algorithm to minimize a chi2 merit function comparing the star distributions in the observed CMD and the CMD of a synthetic stellar population. A parametrization

Ori Hirschberg, David Mukamel, Gunter M. Schütz

Condensation phenomena in non-equilibrium systems have been modeled by the zero-range process, which is a model of particles hopping between boxes with Markovian dynamics. In many cases, memory effects in the dynamics cannot be neglected. In an attempt to understand the possible impact of temporal correlations on the condensate, we introduce and study a proc

Hamid Reza Afshar, Shahrokh Parvizi

The compactification of 6 dimensional Salam-Sezgin model in the presence of 3-form flux H is investigated. We find a torus topology for this compactification with two cusps which are the places of branes, while at the limit of large size L of the compact direction we also obtain sphere topology. This resembles the Randall-Sundrum I,II model. The branes at on

Josep M. Paredes

Radio observations of very high energy (VHE) gamma-ray sources are fundamental to identify and reveal their nature, as well as to understand the physics behind these energetic sources. I will comment on some characteristics of extragalactic sources detected at TeV energies and radio wavelengths, and galactic sources such as gamma-ray binaries, supernova remn

J. Li, G. S. Paraoanu

We analyze a system of two qubits embedded in two different environments. The qubits are coupled to each other and driven on-resonance by two external classical sources. In the secular limit, we obtain exact analytical results for the evolution of the system for several classes of two-qubit mixed initial states. For Werner states we show that the decay of en

Wenjamin Rosenfeld, Markus Weber, Juergen Volz, Florian Henkel

Experimental tests of Bell&#39;s inequality allow to distinguish quantum mechanics from local hidden variable theories. Such tests are performed by measuring correlations of two entangled particles (e.g. polarization of photons or spins of atoms). In order to constitute conclusive evidence, two conditions have to be satisfied. First, strict separation of the

M. I. Moretti, M. Dall&#39;Ora, V. Ripepi, G. Clementini

We present the first V, B-V color-magnitude diagram of the Leo IV dwarf spheroidal galaxy, a faint Milky Way satellite recently discovered by the Sloan Digital Sky Survey. We have obtained B,V time-series photometry reaching about half a magnitude below the Leo IV turnoff, which we detect at V= 24.7 mag, and have performed the first study of the variable sta

Leonardo Galeta, Dan Pirjol, Carlos Schat

We show how to match the Isgur-Karl model to the spin-flavor quark operator expansion used in the 1/Nc studies of the non-strange negative parity L=1 excited baryons. Using the transformation properties of states and interactions under the permutation group S_3 we are able to express the operator coefficients as overlap integrals, without making any assumpti

R. Kleiss, G. van den Oord

A recursive computation of scattering amplitudes including Majorana fermions requires a consistent definition of the fermion flow, which is introduced by Denner et al. in a diagrammatic setting. A systematic treatment in the off-shell current formalism is proposed, which involves explicit reversal of fermion currents.

Halina Abramowicz

Over the last two decades, the HERA collider has provided a large amount of new information about QCD dynamics at high energy. While the most appreciated are the measurements of the proton structure functions in a wide range of parton momentum x and virtuality Q^2, it is hard to believe that some of the observations at HERA which do not fit the simple pictur

Thomas Bauer, Claus Falter

The phonon dynamics of the low-temperature superconductor Sr$_{2}$RuO$_{4}$ is calculated quantitatively in linear response theory and compared with the structurally isomorphic high-temperature superconductor La$_{2}$CuO$_{4}$. Our calculation corrects for a typical deficit of LDA-based calculations which always predict a too large electronic $k_{z}$-dispers

Peter Harremoes, Oliver Johnson, Ioannis Kontoyiannis

Renyi&#39;s &#34;thinning&#34; operation on a discrete random variable is a natural discrete analog of the scaling operation for continuous random variables. The properties of thinning are investigated in an information-theoretic context, especially in connection with information-theoretic inequalities related to Poisson approximation results. The classical

Tanwi Ghosh, Soumitra SenGupta

In this work we study both charged and uncharged particles tunneling across the horizon of spherically symmetric dilaton-axion black holes using Parikh-Wilczek tunneling formalism. Such black hole solutions have much significance in string theory based models. For different choices of the dilaton and axion couplings with the electromagnetic field, we show th

Marcus Kaiser, Claus C. Hilgetag, Arjen van Ooyen

Neural connectivity at the cellular and mesoscopic level appears very specific and is presumed to arise from highly specific developmental mechanisms. However, there are general shared features of connectivity in systems as different as the networks formed by individual neurons in Caenorhabditis elegans or in rat visual cortex and the mesoscopic circuitry of

Chris Giannella

Consider a dataset of n(d) points generated independently from R^d according to a common p.d.f. f_d with support(f_d) = [0,1]^d and sup{f_d([0,1]^d)} growing sub-exponentially in d. We prove that: (i) if n(d) grows sub-exponentially in d, then, for any query point q^d in [0,1]^d and any epsilon>0, the ratio of the distance between any two dataset points and

Sushan Konar

There has been strong observational evidence suggesting a causal connection between the binary history of neutron stars and the evolution of their magnetic field. In this article we discuss one of the plausible mechanisms proposed for the evolution of the surface magnetic field, that of the diamagnetic screening of the field by accreted material.

V. I. Sugakov

A theory of the separation of a system of indirect excitons into a condensed and a gaseous phases with the formation of regular patterns of alternating phases in inhomogeneous external fields is developed. The theory is applied to the study of the non-uniform distribution of the exciton density in a double quantum well under a slot cut in a metallic electrod

Martin Holmes, Laurent Romary

We examine the issue of digital formats for document encoding, archiving and publishing, through the specific example of &#34;born-digital&#34; scholarly journal articles. We will begin by looking at the traditional workflow of journal editing and publication, and how these practices have made the transition into the online domain. We will examine the range

Tyrrell B. McAllister

In 1976, P. R. Scott characterized the Ehrhart polynomials of convex integral polygons. We study the same question for Ehrhart polynomials and quasi-polynomials of \emph{non}-integral convex polygons. Define a \emph{pseudo-integral polygon}, or \emph{PIP}, to be a convex rational polygon whose Ehrhart quasi-polynomial is a polynomial. The numbers of lattice

Mark S. Williamson, Vlatko Vedral

When a multi-qubit state evolves under local unitaries it may obtain a geometric phase, a feature dependent on the geometry of the state&#39;s projective Hilbert space. A correction term to this geometric phase in addition to the local subsystem phases may appear from correlations between the subsystems. We find this correction term can be characterized comp

J-M. Frère

While leptogenesis is a very solid but hard to check contender for the generation of the observed excess of baryons over anti-baryons in the Universe, we show that the observation of gauge bosons associated with right-handed currents at present or future colliders would suffice to disprove its most canonical mechanism.

Florian Niedermeier, Michael Niedermeier, Harald Kosch

In this paper, the performance of the emerging MPEG-4 SVC CODEC is evaluated. In the first part, a brief introduction on the subject of quality assessment and the development of the MPEG-4 SVC CODEC is given. After that, the used test methodologies are described in detail, followed by an explanation of the actual test scenarios. The main part of this work co

T. M. Janssen, T. Prokopec

In this paper we consider a massless scalar field, with a possible coupling $ξ$ to the Ricci scalar in a $D$ dimensional FLRW spacetime with a constant deceleration parameter $q=ε-1$, $ε=-{\dot{H}}/{H^2}$. Correlation functions for the Bunch-Davies vacuum of such a theory have long been known to be infrared divergent for a wide range of values of $ε$. We res

Kanan K. Datta

The epoch of reionization is one of the least known chapters in the evolutionary history of the Universe. This thesis investigates two major approaches to unveil the reionization history of the Universe using HI 21-cm maps.The most discussed approach has been to study the global statistical properties of the reionization HI 21-cm. We develop the formalism to

Winfried Leidemann, Victor D. Efros, Giuseppina Orlandini, Edward L. Tomusiak

The threshold transverse response functions R_T(q,omega) for 3He and 3H are calculated using the AV18 nucleon-nucleon potential, the UrbanaIX three-body force, and the Coulomb potential. Final states are completely taken into account via the Lorentz integral transform technique. Consistent two-body pi- and rho-meson exchange currents as deduced using the Are

S. Sakiroglu, U. Erkarslan, G. Oylumluoglu, A. Siddiki

The thermally activated behavior of the gate defined narrow Hall bars is studied by analyzing the existence of the incompressible strips within a Hartree-type approximation. We perform self-consistent calculations considering the linear response regime, supported by a local conductivity model. We investigate the variation of the activation energy depending o

Bartolomé Coll, Joan J. Ferrando, Juan A. Morales-Lladosa

A {\em relativistic positioning system} consists in a set of four clocks broadcasting their respective proper time by means of light signals. Among them, the more important ones are the {\em auto-located positioning systems,} in which every clock broadcasts not only its proper time but also the proper times that it receives from the other three. At this leve

Kotaro Kawatani

There is two group actions on the Fano scheme of lines such that the quotient becomes an irreducible symplectic manifold. We showed that both quotients are birational to the generalized Kummer variety or the 2-points Hilbert scheme of a K3 surface.

Zohir Bouzid, Maria Potop-Butucaru, Sébastien Tixeuil

We propose the first deterministic algorithm that tolerates up to $f$ byzantine faults in $3f+1$-sized networks and performs in the asynchronous CORDA model. Our solution matches the previously established lower bound for the semi-synchronous ATOM model on the number of tolerated Byzantine robots. Our algorithm works under bounded scheduling assumptions for

Yasto Kimura

We construct elements of the third quandle homology groups of knot quandles, which are called the shadow fundamental classes. They play the same roles for the shadow quandle cocycle invariants of knots as the fundamental classes of knot quandles does for the quandle cocycle invariants. As an application of the shadow fundamental classes, we show the relation