July 2006 arXiv papers — page 25

Aijun Du, Jinqiao Duan

Invariant manifolds facilitate the understanding of nonlinear stochastic dynamics. When an invariant manifold is represented approximately by a graph for example, the whole stochastic dynamical system may be reduced or restricted to this manifold. This reduced system may provide valuable dynamical information for the original system. The authors have derived

B. Bidabad, S. Hedayatian

Let M be an n-dimensional Riemannian manifold and TM its tangent bundle. The conformal and fiber preserving vector fields on TM have well-known physical interpretations and have been studied by physicists and geometricians. Here we define a Riemannian or pseudo-Riemannian lift metric on TM, which is in some senses more general than other lift metrics previou

Vincent Y. B. Chen, William Y. C. Chen, Nancy S. S. Gu

Chu has recently shown that the Abel lemma on summations by parts can serve as the underlying relation for Bailey's ${}_6ψ_6$ bilateral summation formula. In other words, the Abel lemma spells out the telescoping nature of the ${}_6ψ_6$ sum. We present a systematic approach to compute Abel pairs for bilateral and unilateral basic hypergeometric summation

Jorge Caravantes

In this paper we study Fano threefolds with a torsion divisor (Fano--Enriques). Due to this torsion divisor, they can be described as quotients of Fano threefolds by a finite abelian group action. We start from lists of Fano threefolds by Reid, Fletcher and Altınok and check which of them admit such an action with a Fano--Enriques quotient.

Simone Severini

We show that the adjacency matrix M of the line digraph of a d-regular digraph D on n vertices can be written as M=AB, where the matrix A is the Kronecker product of the all-ones matrix of dimension d with the identity matrix of dimension n and the matrix B is the direct sum of the adjacency matrices of the factors in a dicycle factorization of D.

William A. Ponce, Luis A. Sanchez

We carry a systematic study of possible extensions of the standard model based on the gauge group SU(3)_c X SU(4)_L X U(1)_X. We consider both models with particles with exotic electric charges and models which do not contain exotic electric charges neither in the gauge boson sector nor in the fermion sector. For the first case an infinite number of models c

P. R. Stone, M. A. Scarpulla, R. Farshchi, I. D. Sharp

We have measured the X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) at the Mn L3,2 edges in ferromagnetic Ga1-xMnxP films for 0.018<x<0.042. Large XMCD asymmetries at the L3 edge indicate significant spin-polarization of the density of states at the Fermi energy. The spectral shapes of the XAS and XMCD are nearly identical with those for

P. C. Cortes, R. M. Crutcher

We present polarization maps of G30.79 FIR 10 (in W43) from thermal dust emission at 1.3 mm and from CO J=$2 \to 1$ line emission. The observations were obtained using the Berkeley-Illinois-Maryland Association array in the period 2002-2004. The G30.79 FIR 10 region shows an ordered polarization pattern in dust emission, which suggests an hourglass shape for

P. C. Cortes, R. M. Crutcher, B. C. Matthews

We present polarization maps of NGC2071IR from thermal dust emission at 1.3 mm and from CO J=$2 \to 1$ line emission. The observations were obtained using the Berkeley-Illinois-Maryland Association array in the period 2002-2004. We detected dust and line polarized emission from NGC2071IR that we used to constrain the morphology of the magnetic field. From CO

M. Davis, P. Guhathakurta, N. Konidaris, J. A. Newman

In this the first of a series of Letters, we present a description of the panchromatic data sets that have been acquired in the Extended Groth Strip region of the sky. Our survey, the All-wavelength Extended Groth strip International Survey (AEGIS), is intended to study the physical properties and evolutionary processes of galaxies at z ~ 1. It includes the

R. Landi, L. Bassani, A. Malizia, N. Masetti

In order to provide a firm identification of the newly discovered Galactic TeV sources, a search for counterparts in a broad band from soft X-ray to soft gamma-rays is crucial as data in these wavebands allow us to distinguish between different types of suggested models (for example leptonic versus hadronic) and, in turn, to disentangle their nature. In this

T. T. Barnaveli, T. T. Barnaveli, N. A. Eristavi, I. V. Khaldeeva

The distribution of EAS hadronic component energy fluxes through the ionization calorimeter in the primary energy range ~ 3x10^13 - 10^16 eV is considered. The EAS, carrying the zero or the minimal flux of the hadron component energy are extracted. The conclusion supports the existence of izotropic gamma-radiation in the primary energy region E_0 ~ 1x10^14 -

Jim Hinton

The inner few hundred parsecs of our galaxy provide a laboratory for the study of the production and propagation of energetic particles. Very-high-energy gamma-rays provide an effective probe of these processes and, especially when combined with data from other wave-bands, gamma-rays observations are a powerful diagnostic tool. Within this central region, da

M. Huarte-Espinosa, S. Mendoza

The idea of a unified model for all astrophysical jets has been considered for quite some time. We present here a few scaling laws relevant to all type of astrophysical jets, analogous to those of \citet{sams96} which are widely used for astrophysical black holes. We use Buckingham&#39;s $ Π$ theorem of dimensional analysis to obtain a family of dimensional

Kenji Bekki, Yashuhiro Shioya, Matthew Whiting

We investigate the relative importance of starbursts and AGN in nuclear activities of ultra-luminous infrared galaxies (ULIRGs) based on chemodynamical simulations combined with spectrophotometric synthesis codes. We numerically investigate both the gas accretion rates (m_acc) onto super massive black holes (SMBHs) and the star formation rates (m_sf) in ULIR

Cristiano Porciani, Peder Norberg

We present detailed clustering measurements for a flux limited sample of 14,000 quasars extracted from the 2dF QSO Redshift Survey (2QZ) in the redshift range 0.8<z<2.1. After splitting the sample into three redshift bins and each of them into six luminosity intervals, we estimate the quasar projected auto and cross-correlation functions at a given redshift

Catharinus Dijkstra, Angela Speck

Asymptotic Giant Branch (AGB) stars generally have spherically symmetric envelopes, whereas most post-AGB stars and Planetary Nebulae (PNe) show axisymmetric circumstellar envelopes. While various mechanisms for axisymmetric circumstellar structures may explain the shapes of PNe, they do not address how the shape of the circumstellar shell evolves. Here we a

D. Salabert, S. J. Jiménez-Reyes

We have used observations made with the helioseismic instrument LOWL collected over $\sim$ 6 years to carry out an independent study of the variations of the p-mode damping and excitation rates with solar activity. We observe significant variations in the mode height, mode width and mode velocity power over a wide range of angular degree values. Their sensit

Troy A. Porter, Igor V. Moskalenko, Andrew W. Strong

The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV gamma-rays; long awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the ``knee&#39;&#39; energie

Puragra Guhathakurta, James C. Ostheimer, Karoline M. Gilbert, R. Michael Rich

Understanding galaxy formation involves look-back and fossil-record studies of distant and nearby galaxies, respectively. Debris trails in our Galaxy&#39;s spheroidal halo of old stars provide evidence of &#34;bottom-up&#34; formation via tidal disruption/merging of dwarf satellite galaxies, but it is difficult to study our Galaxy&#39;s large-scale structure

Chandra Nair, Balaji Prabhakar, Devavrat Shah

Let $X$ be a discrete random variable with support $S$ and $f : S \to S^\prime$ be a bijection. Then it is well-known that the entropy of $X$ is the same as the entropy of $f(X)$. This entropy preservation property has been well-utilized to establish non-trivial properties of discrete stochastic processes, e.g. queuing process \cite{prg03}. Entropy as well a

Qi Li, John Toner, D. Belitz

We analytically calculate the energy, magnetization curves (B(H)), and elasticity of skyrmion flux lattices in p-wave superconductors near the lower critical field H_c1, and use these results with the Lindemann criterion to predict their melting curve. In striking contrast to vortex flux lattices, which always melt at an external field H > H_c1, skyrmion flu

Kathryn M. Zurek, Craig J. Hogan, Thomas R. Quinn

We model the formation, evolution and astrophysical effects of dark compact Scalar Miniclusters (``ScaMs&#39;&#39;). These objects arise when a scalar field, with an axion-like or Higgs-like potential, undergoes a second order phase transition below the QCD scale. Such a scalar field may couple too weakly to the standard model to be detectable directly throu

Ovidiu I. Patu

We calculate the bulk contribution for the doubly degenerated largest eigenvalue of the transfer matrix of the eight vertex model with an odd number of lattice sites N in the disordered regime using the generic equation for roots proposed by Fabricius and McCoy. We show as expected that in the thermodynamic limit the result coincides with the one in the N ev

Mohamed E. Kelabi

This paper is withdrawn.

Onur Hosten, Matthew T. Rakher, Julio T. Barreiro, Nicholas A. Peters

Mitchison and Jozsa recently suggested that the &#34;chained-Zeno&#34; counterfactual computation protocol recently proposed by Hosten et al. is counterfactual for only one output of the computer. This claim was based on the existing abstract algebraic definition of counterfactual computation, and indeed according to this definition, their argument is correc

C. A. Lamas, D. C. Cabra, M. D. Grynberg, G. L. Rossini

We study the magnetic properties of two types of one dimensional XX spin 1/2 chains. The first type has only nearest neighbor interactions which can be either antiferromagnetic or ferromagnetic and the second type which has both nearest neighbor and next nearest neighbor interactions, but only antiferromagnetic in character. We study these systems in the pre

Rodolfo A. Diaz, William J. Herrera, J. Virgilio Niño

For several configurations of charges in the presence of conductors, the method of images permits us to obtain some observables associated with such a configuration by replacing the conductors with some image charges. However, simple inspection shows that the potential energy associated with both systems does not coincide. Nevertheless, it can be shown that

Oleg A. Starykh, Leon Balents

We investigate the phase diagram of the anisotropic spin-1/2 triangular lattice antiferromagnet, with interchain diagonal exchange J&#39; much weaker than the intrachain exchange J. We find that fluctuations lead to a competition between (commensurate) collinear antiferromagnetic and (zig-zag) dimer orders. Both states differ in symmetry from the spiral orde

Laurence Eyles, Andrew Bunker, Richard Ellis, Mark Lacy

We measure the ages, stellar masses, and star formation histories of z~6 galaxies, observed within 1Gyr of the Big Bang. We use imaging from HST and Spitzer from the public &#34;Great Observatories Origins Deep Survey&#34;, coupled with ground-based near-infrared imaging, to measure the spectral energy distributions from 0.8-5microns, spanning the rest-frame

Igor I. Smolyaninov

Recently it was suggested that Hawking radiation may be observed in a nonlinear electromagnetic waveguide upon propagation of an optical pulse. We show that the spectral characteristics of the Hawking effect in such a waveguide are indistinguishable from the well-known effect of frequency broadening of an optical pulse due to self-phase modulation. Furthermo

Jin-Ho Cho, Soonkeon Nam

We study various bubble solutions in string/M theories obtained by double Wick rotations of (non-)extremal brane configurations. Typically, the geometry interpolates de Sitter space-time times non-compact extra-dimensional space in the near-bubble wall region and the asymptotic flat Minkowski space-time. These bubble solutions provide nice background geometr

Lars Winther Christensen, Oana Veliche

Let $R$ be a commutative noetherian ring with a dualizing complex. By recent work of Iyengar and Krause, the difference between the category of acyclic complexes and its subcategory of totally acyclic complexes measures how far $R$ is from being Gorenstein. In particular, $R$ is Gorenstein if and only if every acyclic complex is totally acyclic. In this note

Sucharit Sarkar

The earlier article tried to construct an algorithm to compute the Heegaard Floer homology \hat{HF}(Y) for a 3-manifold Y. However there is an error in a proof which the author, as of now, is unable to fix.

Nickolay Korabel, George M. Zaslavsky

Discrete nonlinear Schrodinger equation (DNLS) describes a chain of oscillators with nearest neighbor interactions and a specific nonlinear term. We consider its modification with long-range interaction through a potential proportional to $1/l^{1+α}$ with fractional $α< 2$ and $l$ as a distance between oscillators. This model is called $α$DNLS. It exhibits c

Thomas Appelquist, Yang Bai, Maurizio Piai

We include the standard-model (SM) leptons in a recently proposed framework for the generation of quark mass ratios and Cabibbo-Kobayashi-Maskawa (CKM) mixing angles from an SU(3) family gauge interaction. The set of SM-singlet scalar fields describing the spontaneous breaking is the same as employed for the quark sector. The imposition at tree-level of the

Anthony Quinn, Hubert Mantz, Karin Jacobs, Markus Bellion

We have studied the adsorption kinetics of the protein amylase at solid/liquid interfaces. Offering substrates with tailored properties, we are able to separate the impact of short- and long-range interactions. By means of a colloidal Monte Carlo approach including conformational changes of the adsorbed proteins induced by density fluctuations, we develop a

Gianluca Calcagni, Marina Cortes

In the context of loop quantum cosmology, we consider an inflationary era driven by a canonical scalar field and occurring in the semiclassical regime, where spacetime is a continuum but quantum gravitational effects are important. The spectral amplitude and index of scalar perturbations on an unperturbed de Sitter background are computed at lowest order in

Li Yang, Bao Li

A class of quantum protocols of bit commitment is constructed based on the nonorthogonal states coding and the correlation immunity of some Boolean functions. The binding condition of these protocols is guaranteed mainly by the law of causality and the concealing condition is guaranteed by the indistinguishability between nonorthogonal quantum states and the

Richard A. Battye, Bjorn Garbrecht, Adam Moss

We point out that the inclusion of a string component contributing around 5% to the CMB power spectrum amplitude on large scales can increase the preferred value of the spectral index n_s of density fluctuations measured by CMB experiments. While this finding applies to any cosmological scenario involving strings, we consider in particular models of supersym

Stephen. R. Sharpe

These lectures describe the use of effective field theories to extrapolate results from the parameter region where numerical simulations of lattice QCD are possible to the physical parameters (physical quark masses, infinite volume, vanishing lattice spacing, etc.). After a brief introduction and overview, I discuss three topics: 1) Chiral perturbation theor

Lars Kadison

An algebra extension $A \| B$ is right depth two in this paper if its tensor-square is $A$-$B$-isomorphic to a direct summand of any (not necessarily finite) direct sum of $A$ with itself. For example, normal subgroups of infinite groups, infinitely generated Hopf-Galois extensions and infinite dimensional algebras are depth two in this extended sense. The a

P. A. Boyle, M. A. Donnellan, J. M. Flynn, A. Juttner

We present a lattice computation of the first moment of the kaon&#39;s leading-twist distribution amplitude. The results were computed using ensembles with 2+1 dynamical flavours with the domain wall fermion action and Iwasaki gauge action from the RBC and UKQCD joint dataset. The first moment is non-zero because of SU(3)-breaking effects, and we find that w

C. Sevik, C. Bulutay

High-dielectric constant and wide band gap oxides have important technological applications. The crystalline oxide polymorphs having lattice constant compatibility to silicon are particularly desirable. One recently reported candidate is the inverse silver oxide phase of SiO$_2$. First-principles study of this system together with its isovalent equivalents G

James Y-K. Cho, Kristen Menou, Brad Hansen, Sara Seager

We present results from a set of over 300 pseudospectral simulations of atmospheric circulation on extrasolar giant planets with circular orbits. The simulations are of high enough resolution (up to 341 total and sectoral modes) to resolve small-scale eddies and waves, required for reasonable physical accuracy. In this work, we focus on the global circulatio

Diana Avella-Alaminos, Christof Geiss

We define derived equivalent invariants for gentle algebras, constructed in an easy combinatorial way from the quiver with relations defining these algebras. Our invariants consist of pairs of natural numbers and contain important information about the algebra and the structure of the stable Auslander-Reiten quiver of its repetitive algebra. As a by-product

J. S. Jenkins, H. R. A. Jones, C. G. Tinney, R. P. Butler

We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphere. The stars are targets or candidates to be targets for the Anglo-Australian Planet Search. CaII HK line cores were used to derive activity indices for all of these objects. The indices were converted to the Mt. Wilson system of measurements and logR&#39;HK val

F. Soto, H. Berger, L. Cabo, C. Carballeira

Electric and magnetic characterization of NbSe2 single crystals is first presented in detail. Then, some preliminary measurements of the fluctuation-diamagnetism (FD) above the transition temperature Tc are presented. The moderate uniaxial anisotropy of this compound allowed us to observe the fluctuation effects for magnetic fields H applied in the two main

Matthias Scheid, Michael Wimmer, Dario Bercioux, Klaus Richter

We investigate the possiblity of creating directed spin-polarized currents in a two-dimensional electron gas (2DEG) subject to an asymmetric magnetic field and an external adiabatic driving. We thereby generalize concepts of quantum charge ratchets to the case with spin. Due to the Zeeman term in the Hamiltonian, spin-up and -down electrons experience differ

Richard L. White, David J. Helfand, Robert H. Becker, Eilat Glikman

We present a technique to explore the radio sky into the nanoJansky regime by employing image stacking using the FIRST survey. We first discuss the non-intuitive relationship between the mean and median values of a distribution that is dominated by noise, followed by an analysis of the systematic effects present in FIRST&#39;s 20cm VLA snapshot images. Image

Philippe de Forcrand, Owe Philipsen

We present numerical results for the location of the chiral critical line at finite temperature and zero and non-zero baryon density for QCD with N_f=2+1 flavours of staggered fermions on lattices with temporal extent N_t=4. For degenerate quark masses, we compare our results obtained with the exact RHMC algorithm with earlier, inexact R-algorithm results an

Ludmila Praxmeyer, Piotr Wasylczyk, Czeslaw Radzewicz, Krzysztof Wodkiewicz

We present experimental data of the frequency resolved optical gating (FROG) measurements of light pulses revealing interference features corresponding to sub-Planck structures in phase space. For superpositions of pulses a small, sub-Fourier shift in the carrier frequency leads to a state orthogonal to the initial one, although in the representation of stan

Guang Wu, Jie Chen, Yao Li, Lilin Xu

We analyze the application of bright reference pulses to prevent the photon-number-splitting attack in weak-pulse quantum key distribution. Under the optimal eavesdropping strategy as far as we know, the optimal parameters of bright reference and signal pulses can ensure a secure transmission distance up to 146 km. To realize the quantum key distribution sce

Cemsinan Deliduman

A gauge theory of gravity is defined in 6 dimensional non-commutative space-time. The gauge group is the unitary group U(2,2), which contains the homogeneous Lorentz group, SO(4,2), in 6 dimensions as a subgroup. It is shown that, after the Seiberg-Witten map, in the corresponding theory the lowest order corrections are first order in the non-commutativity p

Barry R. Holstein

The factorization property of graviton scattering amplitudes is reviewed and show to be valid only if the &#34;natural&#34; value of the gyromagnetic ratio $g_S=2$ is employed -- independent of spin.

C. C. Homes, R. P. S. M. Lobo, P. Fournier, A. Zimmers

The optical properties of single crystal Pr_{1.85}Ce_{0.15}CuO_4 have been measured over a wide frequency range above and below the critical temperature (T_c \simeq 20 K). In the normal state the coherent part of the conductivity is described by the Drude model, from which the scattering rate just above T_c is determined to be 1/τ\simeq 80 cm^{-1}. The condi

Havard Alnes, Morad Amarzguioui

The current authors have previously shown that inhomogeneous, but spherically symmetric universe models containing only matter can yield a very good fit to the SNIa data and the position of the first CMB peak. In this work we examine how far away from the center of inhomogeneity the observer can be located in these models and still fit the data well. Further

P. Contucci, C. Giardina&#39;, C. Giberti, G. Parisi

We test the property of ultrametricity for the spin glass three-dimensional Edwards-Anderson model in zero magnetic field with numerical simulations up to $20^3$ spins. We find an excellent agreement with the prediction of the mean field theory. Since ultrametricity is not compatible with a trivial structure of the overlap distribution our result contradicts

Pascal Naidon, Eite Tiesinga, William F. Mitchell, Paul S. Julienne

We point out that theories describing s-wave collisions of bosonic atoms confined in one- or two-dimensional geometries can be extended to much tighter confinements than previously thought. This is achieved by replacing the scattering length by an energy-dependent scattering length which was already introduced for the calculation of energy levels under 3D co

Adrian von Muehlenen, Nicolas Errien, Michel Schaer, Marie-Noelle Bussac

We present the first thermoelectric measurements on pentacene field effect transistors. We report high values of the Seebeck coefficient at room temperature between 240 and 500 micro V/K depending on the dielectric surface treatment. These values are independent of the thickness of the channel and of the applied gate voltage. Two contributions to the Seebeck

John B. Etnyre, Burak Ozbagci

We construct, somewhat non-standard, Legendrian surgery diagrams for some Stein fillable contact structures on some plumbing trees of circle bundles over spheres. We then show how to put such a surgery diagram on the pages of an open book for $S^3,$ with relatively low genus. Thus we produce open books with low genus pages supporting these Stein fillable con

Volker Hannstein, Gerhard C. Hegerfeldt

We consider a slow particle with wave function $ψ_t(\vec{x})$, moving freely in some direction. A mirror is briefly switched on around a time $T$ and its position is scanned. It is shown that the measured reflection probability then allows the determination of $|ψ_T(\vec{x})|^2$. Experimentally available atomic mirrors should make this method applicable to t

M. Ausloos, R. Lambiotte

We follow up on the study of correlations between GDP&#39;s of rich countries. We analyze web-downloaded data on GDP that we use as individual wealth signatures of the country economical state. We calculate the yearly fluctuations of the GDP. We look for forward and backward correlations between such fluctuations. The system is represented by an evolving net

N L Chuprikov, O V Spiridonova

Scattering a quantum particle by a self-similar fractal potential on a Cantor set is investigated. We present a new type of solution of the functional equation for the transfer matrix of this potential, which was derived earlier from the Schrödinger equation.

K. Buchta, Ö. Legeza, E. Szirmai, J. Sólyom

The one-dimensional SU$(n)$ Hubbard model is investigated numerically for $n=2,3,4$, and 5 at half filling and $1/n$ filling using the density-matrix renormalization-group (DMRG) method. The energy gaps and various quantum information entropies are calculated. In the half-filled case, finite spin and charge gaps are found for arbitrary positive $U$ if $n > 2

Qasem Exirifard

All the linear alpha-prime corrections, however excluding the gravitational Chern-Simons correction, are studied in the toroidally compactified critical Heterotic string theory. These corrections are computed to the entropy for a BPS static spherical four dimensional dyonic black hole which represents a wrapped fundamental string carrying arbitrary winding a

Motoi Endo, Masahiro Kawasaki, Fuminobu Takahashi, T. T. Yanagida

We point out that supergravity effects enable the inflaton to decay into all matter fields, including the visible and the supersymmetry breaking sectors, once the inflaton acquires a non-vanishing vacuum expectation value. The new decay processes have great impacts on cosmology; the reheating temperature is bounded below; the gravitinos are produced by the i

Paul J. Werbos

Mathematical tools related to coherence theory and classical-quantum equivalence, due to Wigner and Glauber, are essential to modern, practical and empirical understanding of electromagnetics in areas like quantum optics and nanoelectronics. This paper specifies how an extension of these same tools (especially Glauber&#39;s &#34;Q&#34; mapping) can be applie

Yasutaka Nishida, Tomokazu Ookubo

We investigate the behavior of the resistivity around valence transition in the one-dimensional extended periodic Anderson model (PAM) with the Coulomb repulsion between f and conduction electron U_fc. By using 1/N-expansion in the leading order in (1/N)^0, where N is the spin-orbital degeneracy of f-electrons, valence transition happens at critical U_fc wit

Radovan Dermisek, Hyung Do Kim, Ian-Woo Kim

We study gauge mediation of supersymmetry breaking in SU(5) supersymmetric grand unified theory with gauge fields as messengers. The generated soft supersymmetry breaking parameters lead to close to maximal mixing scenario for the Higgs mass and highly reduce the fine tuning of electroweak symmetry breaking. All gaugino, squark and slepton masses are determi

Daniel A. Beard, Hong Qian

Chemical reaction systems operating in nonequilibrium open-system states arise in a great number of contexts, including the study of living organisms, in which chemical reactions, in general, are far from equilibrium. Here we introduce a theorem that relates forward and re-verse fluxes and free energy for any chemical process operating in a steady state. Thi

Christina V. Kraus, Michael M. Wolf, J. Ignacio Cirac

We investigate the power of quantum systems for the simulation of Hamiltonian time evolutions on a cubic lattice under the constraint of translational invariance. Given a set of translationally invariant local Hamiltonians and short range interactions we determine time evolutions which can and those that can not be simulated. Whereas for general spin systems

Geraldo A. Barbosa

This work shows how a secure Internet for users A and B can be implemented through a fast key distribution system that uses physical noise to encrypt information transmitted in deterministic form. Starting from a shared secret random sequence between them, long sequences of fresh random bits can be shared in a secure way and not involving a third party. The

James S. Bolton, Martin G. Haehnelt

We use state-of-the-art hydrodynamical simulations combined with a 1D radiative transfer code to assess the extent to which the highly ionized regions observed close to z~6 quasars, which we refer to as near-zones, can constrain the ionization state of the surrounding IGM. We find the appearance in Lya absorption of a quasar HII ionization front expanding in

Thorsten Renk

Hard pQCD processes taking place in ultrarelativistic heavy-ion collisions are a well-calibrated probe. It is believed that the interaction with the surrounding medium of outgoing partons from a hard vertex is capable of revealing details of the medium. We demonstrate that correlation measurements of hard photon-hadron back-to-back coincidences are a tool su

Ronald Meester, Marieke Collins, Richard Gill, Michiel van Lambalgen

We discuss the statistics involved in the legal case of the nurse Lucia de B. in The Netherlands, 2003-2004. Lucia de B. witnessed an unusually high number of incidents during her shifts, and the question arose as to whether this could be attributed to chance. We discuss and criticise the statistical analysis of Henk Elffers, a statistician who was asked by

V. V. Kryssanov, F. J. Rinaldo, H. Ogawa, E. Kuleshov

The presented work proposes a novel approach to model the citation rate. The paper begins with a brief introduction into informetrics studies and highlights drawbacks of the contemporary approaches to modeling the citation process as a product of social interactions. An alternative modeling framework based on results obtained in cognitive psychology is then

R. Arevalo, A. Garcimartin, D. Maza

The silo discharge process is studied by molecular dynamics simulations. The development of the velocity profile and the probability density function for the displacements in the horizontal and vertical axis are obtained. The PDFs obtained at the beginning of the discharge reveal non-Gaussian statistics and superdiffusive behaviors. When the stationary flow

Lars Bergstrom, Malcolm Fairbairn, Lidia Pieri

The existing and upcoming multiwavelength data from the Galactic Center suggest a comparative study in order to propose or rule out possible models which would explain the observations. In this paper we consider the X-ray synchrotron and the gamma-ray emission due to Kaluza Klein Dark Matter and define a set of parameters for the shape of the Dark Matter hal

Horst Stoecker

The experimental signatures of TeV-mass black hole (BH) formation in heavy ion collisions at the LHC is examined. We find that the black hole production results in a complete disappearance of all very high $p_T$ ({$> 500$} GeV) back-to-back correlated di-jets of total mass {$M > M_f \sim 1$}TeV. We show that the subsequent Hawking-decay produces multiple har

Jean-Guy Caputo, Yuri Gaididei, Franz G. Mertens, Denis D. Sheka

The spin-transfer effect is investigated for the vortex state of a magnetic nanodot. A spin current is shown to act similarly to an effective magnetic field perpendicular to the nanodot. Then a vortex with magnetization (polarity) parallel to the current polarization is energetically favorable. Following a simple energy analysis and using direct spin--lattic

Nakwoo Kim, Jong-Dae Park

We study the supersymmetric solutions of 11-dimensional supergravity with a factor of $AdS_2$ made of M2-branes. Such solutions can provide gravity duals of superconformal quantum mechanics, or through double Wick rotation, the generic bubbling geometry of M-theory which are 1/16-BPS. We show that, when the internal manifold is compact, it should take the fo

Guan-Qiang Li, Li-Bin Fu, Ju-Kui Xue, Xu-Zong Chen

We investigate the collective excitations of a one-dimensional Bose-Einstein condensate (BEC) with repulsive interaction between atoms in a quadratic plus quartic trap. By using the variational approach, the coupled equations of motion for the center-of-mass coordinate of the condensate and its width are derived. Then, two low-energy excitation modes are obt

Mahesh C Shastry, Nithin Nagaraj, Prabhakar G Vaidya

A 1-dimensional generalization of the well known Logistic Map is proposed. The proposed family of maps is referred to as the B-Exponential Map. The dynamics of this map are analyzed and found to have interesting properties. In particular, the B-Exponential Map exhibits robust chaos for all real values of the parameter B >= e^(-4). We then propose a pseudo-ra

Lisa Randall, Geraldine Servant

We argue that the RSI model can provide a strong signature in gravitational waves. This signal is a relic stochastic background generated during the cosmological phase transition from an AdS-Schwarschild phase to the RS1 geometry that should occur at a temperature in the TeV range. We estimate the amplitude of the signal in terms of the parameters of the pot

N. Graham, M. Quandt, O. Schroeder, H. Weigel

We study classically unstable string type configurations and compute the renormalized vacuum polarization energies that arise from fermion fluctuations in a 2+1 dimensional analog of the standard model. We then search for a minimum of the total energy (classical plus vacuum polarization energies) by varying the profile functions that characterize the string.

Xiao-Gang He, A. Zee

Current experimental data on neutrino oscillations are consistent with the tri-bimaximal mixing. If future experimental data will determine a non-zero $V_{e3}$ and/or find CP violations in neutrino oscillations, there is the need to modify the mixing pattern. We find that a simple neutrino mass matrix, resulting from $A_4$ family symmetry breaking with resid

Gunnar Dolling, Martin Wegener, Costas M. Soukoulis, Stefan Linden

We further miniaturize a recently established silver-based negative-index metamaterial design. By comparing transmittance, reflectance and phase-sensitive time-of-flight experiments to theory, we infer a real part of the refractive index of -0.6 at 780 nm wavelength -- which is visible in the laboratory.

C. Dawson, T. Izubuchi, T. Kaneko, S. Sasaki

We calculate the vector form factor in K \to πl νsemileptonic decays at zero momentum transfer f_+(0) from numerical simulations of two-flavor QCD on the lattice. Our simulations are carried out on 16^3 \times 32 at a lattice spacing of a \simeq 0.12 fm using a combination of the DBW2 gauge and the domain-wall quark actions, which possesses excellent chiral

C. C. Leung, H. F. Chau

Real-world networks process structured connections since they have non-trivial vertex degree correlation and clustering. Here we propose a toy model of structure formation in real-world weighted network. In our model, a network evolves by topological growth as well as by weight change. In addition, we introduce the weighted assortativity coefficient, which g

Pinhas Grossman

We consider noncommuting pairs P,Q of intermediate subfactors of an irreducible, finite-index inclusion N in M of II_1 factors such that P and Q are supertransitive with Jones index less than 4 over N. We show that up to isomorphism of the standard invariant, there is a unique such pair corresponding to each even value [P:N]=4cos^2(pi/2n) but none for the od

Antonio Aguilera, Edgardo Ugalde

In this paper we analyze urban spatial segregation phenomenon in terms of the income distribution over a population, and inflationary parameter weighting the evolution of housing prices. For this, we develop a discrete, spatially extended model based in a multi--agent approach. In our model, the mobility of socioeconomic agents is driven only by the housing

Gabriel A. Durkin, Jonathan P. Dowling

A statistical distinguishability based on relative entropy characterises the fitness of quantum states for phase estimation. This criterion is employed in the context of a Mach-Zehnder interferometer and used to interpolate between two regimes, of local and global phase distinguishability. The scaling of distinguishability in these regimes with photon number

Edmund Bertschinger

Weakly interacting massive particles are part of the lepton-photon plasma in the early universe until kinetic decoupling, after which time the particles behave like a collisionless gas with nonzero temperature. The Boltzmann equation for WIMP-lepton collisions is reduced to a Fokker-Planck equation for the evolution of the WIMP distribution including scalar

Kayll Lake

It is shown that an Einstein cluster of WIMPs, WIMPs on stable circular geodesic orbits generating the static spherically symmetric gravitational field of a galactic halo, can exactly reproduce the rotation curve of any galaxy simply by adjusting the local angular momentum distribution and consequent number distribution of the WIMPs. No new physics is involv

Yo&#39;av Rieck

In [Topology 35 (1996) 1005--1023] J H Rubinstein and M Scharlemann, using Cerf Theory, developed tools for comparing Heegaard splittings of irreducible, non-Haken manifolds. As a corollary of their work they obtained a new proof of Waldhausen&#39;s uniqueness of Heegaard splittings of S^3. In this note we use Cerf Theory and develop the tools needed for com

Jose Ramirez, Brian Rider, Balint Virag

We prove that the largest eigenvalues of the beta ensembles of random matrix theory converge in distribution to the low-lying eigenvalues of the random Schroedinger operator -d^2/dx^2 + x + (2/beta^{1/2}) b_x&#39; restricted to the positive half-line, where b_x&#39; is white noise. In doing so we extend the definition of the Tracy-Widom(beta) distributions t

Paulina Marian, Tudor A. Marian

We give a description of the continuous-variable teleportation protocol in terms of the characteristic functions of the quantum states involved. The Braunstein--Kimble protocol is written for an unbalanced homodyne measurement and arbitrary input and resource states. We show that the output of the protocol is a superposition between the input one-mode field

Juan C. Agudelo, Walter Carnielli

We present an original model of paraconsistent Turing machines (PTMs), a generalization of the classical Turing machines model of computation using a paraconsistent logic. Next, we briefl y describe the standard models of quantum computation: quantum Turing machines and quantum circuits, and revise quantum algorithms to solve the so-called Deutsch&#39;s prob

A. Matzkin

Quantum systems in specific regimes display recurrences at the period of the periodic orbits of the corresponding classical system. We investigate the excited hydrogen atom in a magnetic field -- a prototypical system of &#39;quantum chaos&#39; -- from the point of view of the de Broglie Bohm (BB) interpretation of quantum mechanics. The trajectories predict