April 2008 arXiv papers — page 26

J. W. Maluf, F. F. Faria

We consider tetrad fields as reference frames adapted to observers that move along arbitrary timelike trajectories in spacetime. By means of a local Lorentz transformation we can transform these frames into Fermi-Walker transported frames, which define a standard of non-rotation for accelerated observers. Here we present a simple prescription for the constru

Ue-Li Pen, Tzu-Ching Chang, Jeff B. Peterson, Jayanta Roy

We present an overview for the reionization search at GMRT. The forecast sensitivities are promising for an early detection. RFI mitigation has been successful. Several hundred hours of telescope time have already been invested in this ongoing effort, and analysis of the data is in progress.

Myoungjean Bae, Gui-Qiang Chen, Mikhail Feldman

The shock reflection problem is one of the most important problems in mathematical fluid dynamics, since this problem not only arises in many important physical situations but also is fundamental for the theory of multidimensional conservation laws. However, most of the fundamental issues for shock reflection have not been understood. Therefore, it is import

Alejandro Romanelli

We investigate the quantum kicked rotor in resonance subjected to momentum measurements with a Lévy waiting time distribution. We find that the system has a sub-ballistic behavior. We obtain an analytical expression for the exponent of the power law of the variance as a function of the characteristic parameter of the Lévy distribution and connect this anomal

Cristian Rios, Eric Sawyer

We characterize when radial weak solutions to Monge-Ampere equations are smooth. This paper extends previous partial results and also covers Generalized Monge-Ampere equations and infinitely vanishing right hand side.

Valery A. Liskovets

In this note we derive enumerative formulas for several types of labelled acyclic directed graphs by slight modifications of the familiar recursive formula for simple acyclic digraphs. These considerations are motivated by, and based upon, recent combinatorial results in geometric topology obtained by S.Choi, who established exact correspondences between acy

W. M. Grundy, K. S. Noll, J. Virtanen, K. Muinonen

We describe a strategy for scheduling astrometric observations to minimize the number required to determine the mutual orbits of binary transneptunian systems. The method is illustrated by application to Hubble Space Telescope observations of (42355) Typhon-Echidna, revealing that Typhon and Echidna orbit one another with a period of 18.971 +/- 0.006 days an

Stephanie B. Alexander, Richard L. Bishop

A semi-Riemannian manifold is said to satisfy $R\ge K$ (or $R\le K$) if spacelike sectional curvatures are $\ge K$ and timelike ones are $\le K$ (or the reverse). Such spaces are abundant, as warped product constructions show; they include, in particular, big bang Robertson-Walker spaces. By stability, there are many non-warped product examples. We prove the

N. J. Dunstone, G. A. J. Hussain, A. Collier Cameron, S. C. Marsden

We present the first measurements of surface differential rotation on a pre-main sequence binary system. Using intensity (Stokes I) and circularly polarised (Stokes V) timeseries spectra, taken over eleven nights at the Anglo-Australian Telescope (AAT), we incorporate a solar-like differential rotation law into the surface imaging process. We find that both

Erik van Erp

The Atiyah-Singer index theorem is a topological formula for the index of an elliptic differential operator. The topological index depends on a cohomology class that is constructed from the principal symbol of the operator. On contact manifolds, the important Fredholm operators are not elliptic, but hypoelliptic. Their symbolic calculus is noncommutative, an

Alexander Schoenhuth

It is demonstrated how to represent asymptotically mean stationary (AMS) random sources with values in standard spaces as mixtures of ergodic AMS sources. This an extension of the well known decomposition of stationary sources which has facilitated the generalization of prominent source coding theorems to arbitrary, not necessarily ergodic, stationary source

Constantino A. Utreras-Diaz

From the theory of quantum $LC$ circuits with discrete charge, and {\em semiclassical} considerations, we obtain approximate energy eigenvalues, depending on the parameter $q_e^2/h$. Next, we include electrical resistance for the quantum $RLC$ circuit, obtaining a relation that strongly reminds us of the Landauer formula.

S. Bilir, A. Cabrera-Lavers, S. Karaali, S. Ak

We estimated the Galactic model parameters for a set of 36 high-latitude fields included in the currently available Data Release 5 (DR 5) of the Sloan Digital Sky Survey ({\em SDSS}), to explore their possible variation with the Galactic longitude. The thick disc scaleheight moves from $\sim$550 pc at $120^{\circ}<l<150^{\circ}$ to $\sim$720 pc at $250^{\cir

Joshua N. Winn, Matthew J. Holman, Avi Shporer, Jose Fernandez

We present photometry of the exoplanet host star TrES-3 spanning six occultations (secondary eclipses) of its giant planet. No flux decrements were detected, leading to 99%-confidence upper limits on the planet-to-star flux ratio of 0.00024, 0.0005, and 0.00086 in the i, z, and R bands respectively. The corresponding upper limits on the planet&#39;s geometri

Andreas H. W. Küpper, Andrew Macleod, Douglas C. Heggie

We examine the longitudinal distribution of the stars escaping from a cluster along tidal tails. Using both theory and simulations, we show that, even in the case of a star cluster in a circular galactic orbit, when the tide is steady, the distribution exhibits maxima at a distance of many tidal radii from the cluster.

Yueheng Lan, Predrag Cvitanovic

We undertake a systematic exploration of recurrent patterns in a 1-dimensional Kuramoto-Sivashinsky system. For a small, but already rather turbulent system, the long-time dynamics takes place on a low-dimensional invariant manifold. A set of equilibria offers a coarse geometrical partition of this manifold. A variational method enables us to determine numer

Michael Botros Shenouda, Timothy Davidson

We consider the design of multiple-input multiple-output communication systems with a linear precoder at the transmitter, zero-forcing decision feedback equalization (ZF-DFE) at the receiver, and a low-rate feedback channel that enables communication from the receiver to the transmitter. The channel state information (CSI) available at the receiver is assume

Michele Campisi

We establish an expression of the entropy-from-work theorem that is complementary to the one originally proposed in [P. Talkner, P. Hanggi and M. Morillo, arXiv:0707.2307]. In the original expression the final energy is fixed whereas in the present expression the initial energy is fixed.

L. Beaudin, J. Ellis-Monaghan, G. Pangborn, R. Shrock

In this survey, we give a friendly introduction from a graph theory perspective to the q-state Potts model, an important statistical mechanics tool for analyzing complex systems in which nearest neighbor interactions determine the aggregate behavior of the system. We present the surprising equivalence of the Potts model partition function and one of the most

Olivier Brunet

One of the most central and controversial element of quantum mechanics is the use of non zero vectors of a Hilbert space (or, more generally, of one dimension subspaces) for representing the state of a quantum system. In particular, the question whether such a representation is complete has been debated since almost the early days of quantum mechanics. In th

Charles D. Dermer

Auger results on clustering of > 60 EeV ultra-high energy cosmic ray (UHECR) ions and the interpretation of the gamma-ray spectra of TeV blazars are connected by effects from the extragalactic background light (EBL). The EBL acts as an obscuring medium for gamma rays and a reprocessing medium for UHECR ions and protons, causing the GZK cutoff. The study of t

A. B. Vorontsov, I. Vekhter, M. Eschrig

We investigate the influence of spin-orbit coupling in a non-centrosymmetric superconductor on its ground state properties near a surface. We determine the spectrum of Andreev bound states due to surface-induced mixing of bands with opposite spin helicities for a Rashba-type spin-orbit coupling. We find a qualitative change of the Andreev spectrum when we ac

M. Köhler, P. Lunkenheimer, A. Loidl

We report a thorough dielectric characterization of the alpha relaxation of glass forming glycerol with varying additions of LiCl. Nine salt concentrations from 0.1 - 20 mol% are investigated in a frequency range of 20 Hz - 3 GHz and analyzed in the dielectric loss and modulus representation. Information on the dc conductivity, the dielectric relaxation time

J. Schlappa, C. Schüßler-Langeheine, C. F. Chang, Z. Hu

We studied the resonant diffraction signal from stepped surfaces of SrTiO3 at the Ti 2p -> 3d (L2,3) resonance in comparison with x-ray absorption (XAS) and specular reflectivity data. The steps on the surface form an artificial superstructure suited as a model system for resonant soft x-ray diffraction. A small step density on the surface is sufficient to p

A. Aperis, G. Varelogiannis, P. B. Littlewood, B. D. Simons

We have studied the competition and coexistence of staggered triplet SC with d-wave singlet SC and SDW in the mean-field approximation. Detailed numerical studies demonstrate that particle-hole asymmetry mixes these states and therefore they are simultaneously present. Even more interesting were the results of our study of the influence of a uniform magnetic

N. R. Deacon, G. Nelemans, N. C. Hambly

The stellar mass function is one of the fundamental distributions of stellar astrophysics. Its form at masses similar to the Sun was found by Salpeter (1955) to be a power-law $m^{-α}$ with a slope of $α=1.35$. Since then the mass function in the field, in stellar clusters and in other galaxies has been studied to identify variation due to environment and ma

Y. Tokiwa, R. Movshovich, F. Ronning, E. D. Bauer

We investigated the effect of Cd and Hg doping on the first order superconducting (SC) transition and the high field-low temperature SC state of CeCoIn$_5$ by measuring the specific heat of CeCo(In$_{\rm 1-x}$Cd$_{\rm x}$)$_5$ with x=0.0011, 0.0022 and 0.0033 and CeCo(In$_{\rm 1-x}$Hg$_{\rm x}$)$_5$ with x=0.00016, 0.00032, and 0.00048 at temperatures down t

Suvankar Dutta

In this paper we generalize the construction of locally boosted black brane space time to higher derivative gravities. We consider the Gauss-Bonnet term (with coefficient $α&#39;$) as a toy example. We find the solution to the $α&#39;$ corrected Einstein equations to first order in the boundary derivative expansion. This allows us to find the $α&#39;$ correc

M. Buescher

The light scalar mesons a_0/f_0(980) are being investigated at COSY-Juelich by detecting the strong decays into K-K-bar and pi-eta/pi-pi as well as radiative decays into vector mesons. Selected results are discussed with emphasis on recent measurements at the ANKE and WASA spectrometers.

Jianhua Xing, Jing Chen

In their classical work (Proc. Natl. Acad. Sci. USA, 1981, 78:6840-6844), Goldbeter and Koshland mathematically analyzed a reversible covalent modification system which is highly sensitive to the concentration of effectors. Its signal-response curve appears sigmoidal, constituting a biochemical switch. However, the switch behavior only emerges in the &#34;ze

S. I. Fisenko, I. S. Fisenko

Technology for forming stable states of dense high temperature plasma, which can be used, for example, for controlled thermo-nuclear synthesis.

S. Misra, N. C. Bishop, E. Tutuc, M. Shayegan

We report magnetotransport measurements on bilayer GaAs hole systems with unequal hole concentrations in the two layers. At magnetic fields where one layer is in the integer quantum Hall state and the other has bulk extended states at the Fermi energy, the longitudinal and Hall resistances of the latter are hysteretic, in agreement with previous measurements

Robin L. Shelton

This report summarizes the discussions in the Session 1 and Session 3 groups which met to discuss the questions: ``What Physical Processes Drive the Multiphase Interstellar Medium in the Local Bubble?'', and ``What are the Energy and Pressure Balances in the Local Bubble?'' Most of our understanding of the Local Bubble has come from soft X-ray observations,

Robin L. Shelton

The hot Local Bubble surrounding the solar neighborhood has been primarily studied through observations of its soft X-ray emission. The measurements were obtained by attributing all of the observed local soft X-rays to the bubble. However, mounting evidence shows that the heliosphere also produces diffuse X-rays. The source is solar wind ions that have recei

Orsola De Marco, Todd C. Hillwig, A. J. Smith

Shaping axi-symmetric planetary nebulae is easier if a companion interacts with a primary at the top of the asymptotic giant branch. To determine the impact of binarity on planetary nebula formation and shaping, we need to determine the central star of planetary nebula binary fraction and period distribution. The short-period binary fraction has been known t

Grzegorz Litak, Jerzy T. Sawicki

Vibrations of the Jeffcott rotor are modelled by a three degree of freedom system including coupling between lateral and torsional modes. The crack in a rotating shaft of the rotor is introduced via time dependent stiffness with off diagonal couplings. Applying the external torque to the system allows to observe the effect of crack &#34;breathing&#34; and ga

Pasquale Calabrese, Christian Hagendorf, Pierre Le Doussal

We study the time evolution of quantum one-dimensional gapless systems evolving from initial states with a domain-wall. We generalize the path-integral imaginary time approach that together with boundary conformal field theory allows to derive the time and space dependence of general correlation functions. The latter are explicitly obtained for the Ising uni

Grzegorz Litak, Jerzy T. Sawicki

Multifractal analysis has been used to diagnoze cracked and healthy rotors. Is has been shown that the complexity and regularity criteria of the dynamical systems defined by the multiple scaling of the time series can indicate the damages of the rotating shaft.

Debajyoti Bera, Stephen Fenner, Frederic Green, Steve Homer

We define and construct efficient depth-universal and almost-size-universal quantum circuits. Such circuits can be viewed as general-purpose simulators for central classes of quantum circuits and can be used to capture the computational power of the circuit class being simulated. For depth we construct universal circuits whose depth is the same order as the

Michael Rauch

The search for Higgs bosons and extensions of the Standard Model of Elementary Particle Physics are main tasks of the Large Hadron Collider (LHC) at CERN which will start operation mid-2008. In this thesis processes which can be used to detect supersymmetric Higgs bosons at the LHC were considered. First a computer program was written which completes the too

Radoslaw Ryblewski, Wojciech Florkowski

General formulation of hydrodynamics describing transversally thermalized matter created at the early stages of ultra-relativistic heavy-ion collisions is presented. Similarities and differences with the standard three-dimensionally thermalized relativistic hydrodynamics are discussed. The role of the conservation laws as well as the thermodynamic consistenc

Koji Azuma, Masato Koashi, Nobuyuki Imoto

Heisenberg&#39;s uncertainty principle and recently derived many no-go theorems including the no-cloning theorem and the no-deleting theorem have corroborated the idea that we can never access quantum information without causing disturbance. Here we disprove this presumption by predicting a novel phenomenon, `quantum catalysis of information,&#39; where a sy

Patricia Ball, Vladimir M. Braun, Einan Gardi

The QCD description of exclusive decays of the $Λ_b$ baryon involves hadronic matrix elements of non-local light ray operators, the light-cone distribution amplitudes. We introduce the complete set of three--quark distribution amplitudes and calculate the renormalization scale dependence for the leading twist. At leading order in the strong coupling the evol

R. C. Myers, S. E. Vazquez

We discuss the application of the AdS/CFT correspondence to possibly gain new physical insights for the strongly coupled quark-gluon plasma. This article provides an informal summary of a talk given by RCM at the 18th International Conference on General Relativity and Gravitation in July 2007.

The BABAR Collaboration, B. Aubert

We present measurements of branching fractions for five B-meson decays to two-body charmless final states. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 459 million BBbar pairs. The results for branching fractions are, in units of 10^{-6} (upper limits at 90% C.L.): BR(B+ -> etarho+) = 9.9 +/- 1.2 +/- 0.8, B

Timothy Garn, David A. Green, Julia M. Riley, Paul Alexander

We present observations of the Lockman Hole with the Giant Metrewave Radio Telescope (GMRT). Twelve pointings were observed, covering a total area of ~ five square degrees with a resolution of 6 x 5 arcsec, position angle +45deg. The majority of the pointings have an rms noise of 60 microJy/beam before correction for the attenuation of the GMRT primary beam.

N H. Kwong, S. Schumacher, R. Binder

Recent time-resolved differential transmission and Faraday rotation measurements of long-lived electron spin coherence in quantum wells displayed intriguing parametric dependencies. For their understanding we formulate a microscopic theory of the optical response of a gas of optically incoherent excitons whose constituent electrons retain spin coherence, und

P. -A. Söderström

The MEDLEY setup based at The Svedberg Laboratory (TSL), Uppsala, Sweden has previously been used to measure double-differential cross-sections for elastic nd scattering, as well as light ion production reactions for various nuclei in the interaction with neutrons around 95 MeV. When moved to the new beam line, the first experimental campaign was on light-io

Mario Maglione

Triggered by the revival of multiferroic materials, a lot of effort is presently undergoing as to find a coupling between a capacitance and a magnetic field. We show in this report that interfaces are the right way of increasing such a coupling provided free charges are localized on these two-dimensional defects. Starting from commercial diodes at room tempe

J. -M. Marin, Christian Robert

In Chib (1995), a method for approximating marginal densities in a Bayesian setting is proposed, with one proeminent application being the estimation of the number of components in a normal mixture. As pointed out in Neal (1999) and Fruhwirth-Schnatter (2004), the approximation often fails short of providing a proper approximation to the true marginal densit

Kate Lee, Jean-Michel Marin, Kerrie Mengersen, Christian P. Robert

This survey covers state-of-the-art Bayesian techniques for the estimation of mixtures. It complements the earlier Marin, Mengersen and Robert (2005) by studying new types of distributions, the multinomial, latent class and t distributions. It also exhibits closed form solutions for Bayesian inference in some discrete setups. Lastly, it sheds a new light on

Yuri M. Shtemler, Michael Mond, Vladimir Cherniavskii, Ephim Golbraikh

The generalized Kelvin-Helmholtz (KH) and Miles mechanisms of the water wave generation by wind are investigated for two-layer piece-wise linear model of the wind profile. It is shown by asymptotic expansions in small air-to-water density ratio that two mechanisms of the instability operate in quite different scales. Miles&#39; short waves are generated by w

L. W. Wansbeek, B. K. Sahoo, R. G. E. Timmermans, B. P. Das

We report a new technique to determine the van der Waals coeffcients of lithium (Li) atoms based on the relativistic coupled-cluster theory. These quantities are determined using the imaginary parts of the scalar dipole and quadrupole polarizabilities, which are evaluated using the approach that we have proposed in [1]. Our procedure is fully ab initio, and

Xiao-Long Zhang, Kip Bishofberger, Vsevolod Kamerdzhiev, Valery Lebedev

In the Collider Run II, the Tevatron operates with 36 high intensity bunches of 980 GeV protons and antiprotons. Particles not captured by the Tevatron RF system pose a threat to quench the superconducting magnet during acceleration or at beam abort. We describe the main mechanisms for the origination of this uncaptured beam, and present measurements of its

P. Ludwig, K. Balzer, A. Filinov, H. Stolz

We study the Coulomb-to-dipole transition which occurs when the separation $d$ of an electron-hole bilayer system is varied with respect to the characteristic in-layer distances. An analysis of the classical ground state configurations for harmonically confined clusters with $N\leq30$ reveals that the energetically most favorable state can differ from that o

Celine Righi

Using GAP4, we determine the number of ad-nilpotent and abelian ideals of a parabolic subalgebra of a simple Lie algebra of exceptional types E, F or G.

T. Jarlborg

An understanding of spin excitations in cuprates is essential since the mechanism of high-T$_C$ superconductivity might be linked to spin fluctuations. Band calculations for long &#34;1-dimensional&#34; unit cells of La$_2$CuO$_4$ show that the coupling between antiferromagnetic spin waves and phonons is larger for distortions of oxygens than for Cu or La. W

L. Fossati, K. Kolenberg, P. Reegen, W. Weiss

The current knowledge of the abundance pattern in delta Scuti stars is based on the analysis of just a few field stars. We aim to determine the general chemical properties of the atmospheres of delta Scuti stars based on a statistically relevant sample of stars and will investigate whether the abundance pattern is close to solar, an assumption generally made

Sanjiang Li

Markov networks and Bayesian networks are effective graphic representations of the dependencies embedded in probabilistic models. It is well known that independencies captured by Markov networks (called graph-isomorphs) have a finite axiomatic characterization. This paper, however, shows that independencies captured by Bayesian networks (called causal models

Elise Janvresse, Benoît Rittaud, Thierry De La Rue

A random Fibonacci sequence is defined by the relation g_n = | g_{n-1} +/- g_{n-2} |, where the +/- sign is chosen by tossing a balanced coin for each n. We generalize these sequences to the case when the coin is unbalanced (denoting by p the probability of a +), and the recurrence relation is of the form g_n = |λg_{n-1} +/- g_{n-2} |. When λ>=2 and 0 < p <=

Juan Belmonte Beitia, Vladimir V. Konotop, Victor M. Perez Garcia, Vadym E. Vekslerchik

Using similarity transformations we construct explicit solutions of the nonlinear Schrodinger equation with linear and nonlinear periodic potentials. We present explicit forms of spatially localized and periodic solutions, and study their properties. We put our results in the framework of the exploited perturbation techniques and discuss their implications o

J. Hwang, J. Yang, J. P. Carbotte, T. Timusk

A model in which a gap forms in the renormalized electronic density of state (DOS) with missing states recovered just above the pseudogap $Δ_{pg}$, is able to give a robust description of the striking, triangular like, peak seen in the real part of the optical self-energy of underdoped cuprates. We use this model to explore the effect of the pseudogap on the

R. Johne, N. A. Gippius, G. Pavlovic, D. D. Solnyshkov

We show theoretically that entangled photon pairs can be produced on demand through the biexciton decay of a quantum dot strongly coupled to the modes of a photonic crystal. The strong coupling allows to tune the energy of the mixed exciton-photon (polariton) eigenmodes, and to overcome the natural splitting existing between the exciton states coupled with d

D. Raban, B. Heijligers, H. Rottgering, K. Meisenheimer

Aims. Near diffraction-limited images have been taken at 8.9, 11.9, and 12.9 micron for the brightest extragalactic sources in the southern sky, in order to optimally plan N-band observations with MIDI (MID-infrared Interferometric instrument) at the VLTI. Methods. We have assembled a sample of 21 objects consisting of all the AGNs observable from Paranal ob

Daniela Froemberg, Hauke Schmidt-Martens, Igor M. Sokolov, Francesc Sagues

We consider an irreversible autocatalytic conversion reaction A+B -> 2A under subdiffusion described by continuous time random walks. The reactants&#39; transformations take place independently on their motion and are described by constant rates. The analog of this reaction in the case of normal diffusion is described by the Fisher-Kolmogorov-Petrovskii-Pisk

C. Trundle, R. Kotak, J. S. Vink, W. P. S. Meikle

There has been mounting observational evidence in favour of Luminous Blue Variables (LBVs) being the direct progenitors of supernovae. Here we present possibly the most convincing evidence yet for such progenitors. We find multiple absorption component P-Cygni profiles of hydrogen and helium in the spectrum of SN 2005gj, which we interpret as being an imprin

James M. Yearsley

We present a derivation of the propagator for a particle in the presence of the step and delta function potentials. These propagators are known, but we present a direct path integral derivation, based on the path decomposition expansion and the Brownian motion definition of the path integral. The derivation exploits properties of the Catalan numbers, which e

Thibault Damour, Piotr Jaranowski, Gerhard Schäfer

The ADM formalism for two-point-mass systems in $d$ space dimensions is sketched. It is pointed out that the regularization ambiguities of the 3rd post-Newtonian ADM Hamiltonian considered directly in $d=3$ space dimensions can be cured by dimensional continuation (to complex $d$&#39;s), which leads to a finite and unique Hamiltonian as $d\to3$. Some so far

Philip Walther, Markus Aspelmeyer, Anton Zeilinger

We present a scheme, based only on linear optics and standard photon detection, that allows to generate heralded multiphoton entangled states of arbitrary photon number from spontaneous parametric downconversion (PDC) in the weak interaction regime. The scheme also works in the strong interaction regime, i.e., for the production of large photon numbers, when

Hamid Khoshbakht, Farhad Shahbazi, Keivan Aghababaei Samani

In this work we investigate the stability of synchronized states for the Kuramoto model on scale-free and random networks in the presence of white noise forcing. We show that for a fixed coupling constant, the robustness of the globally synchronized state against the noise is dependent on the noise intensity on both kinds of networks. At low noise intensitie

H. Le Sueur, P. Joyez, H. Pothier, C. Urbina

Using a dual-mode STM-AFM microscope operating below 50mK we measured the Local Density of States (LDoS) along small normal wires connected at both ends to superconductors with different phases. We observe that a uniform minigap can develop in the whole normal wire and in the superconductors near the interfaces. The minigap depends periodically on the phase

Hanzhong Zhang, J. F. Owens, Enke Wang, X. -N. Wang

High $p_T$ single and dihadron production is studied within a NLO pQCD parton model with jet quenching in high energy $A+A$ collisions at the RHIC/LHC energy. A simultaneous $χ^2$-fit to both single and dihadron spectra can be achieved within a narrow range of energy loss parameter. Punch-through jets are found to result in the dihadron suppression factor sl

S. Kendall, R. C. Kennicutt, C. Clarke, M. D. Thornley

We use SPITZER IRAC 3.6 and 4.5micron near infrared data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), optical B, V and I and 2MASS Ks band data to produce mass surface density maps of M81. The IRAC 3.6 and 4.5micron data, whilst dominated by emission from old stellar populations, is corrected for small-scale contamination by young stars and PAH

Elise Janvresse, Benoît Rittaud, Thierry De La Rue

We study the generalized random Fibonacci sequences defined by their first nonnegative terms and for $n\ge 1$, $F_{n+2} = \lambda F_{n+1} \pm F_{n}$ (linear case) and $\widetilde F_{n+2} = |\lambda \widetilde F_{n+1} \pm \widetilde F_{n}|$ (non-linear case), where each $\pm$ sign is independent and either $+$ with probability $p$ or $-$ with probability $1-p

Bruno Bellomo, Rosario Lo Franco, Giuseppe Compagno

A procedure that allows to obtain the dynamics of $N$ independent bodies each locally interacting with its own reservoir is presented. It relies on the knowledge of single body dynamics and it is valid for any form of environment noise. It is then applied to the study of non-Markovian dynamics of two independent qubits, each locally interacting with a zero t

P. Tsoutsis, C. Efthymiopoulos, N. Voglis

In a previous paper (Voglis et al. 2006a, paper I) we demonstrated that, in a rotating galaxy with a strong bar, the unstable asymptotic manifolds of the short period family of unstable periodic orbits around the Lagrangian points L$_1$ or L$_2$ create correlations among the apocentric positions of many chaotic orbits, thus supporting a {\it spiral} structur

Neal A. Miller, E. B. Fomalont, K. I. Kellermann, V. Mainieri

We have observed the Extended Chandra Deep Field South (E-CDF-S) using a mosaic of six deep Very Large Array (VLA) pointings at 1.4GHz. In this paper, we present the survey strategy, description of the observations, and the first data release. The observations were performed during June through September of 2007 and included from 15 to 17 ``classic&#39;&#39;

Alin Bostan, Bruno Salvy, Éric Schost

We discuss efficient conversion algorithms for orthogonal polynomials. We describe a known conversion algorithm from an arbitrary orthogonal basis to the monomial basis, and deduce a new algorithm of the same complexity for the converse operation.

M. Ziegler, T. Rauch, E. Reiff, K. Werner

Previous studies aiming at the iron-abundance determination in three PG 1159 stars (K 1-16, PG 1159-035, NGC 7094) and a [WC]-PG 1159 transition star (Abell 78) have revealed that no object shows any iron line in the UV spectrum. The stars are iron-deficient by at least 1 dex, typically. A possible explanation is that iron nuclei were transformed by neutron

Hanzhong Zhang, J. F. Owens, Enke Wang, X. -N. Wang

The dihadron spectra in high energy $AA$ collisions are studied within the NLO pQCD parton model with jet quenching taken into account. The high $p_T$ dihadron spectra are found to be contributed not only by jet pairs close and tangential to the surface of the dense matter but also by punching-through jets survived at the center while the single hadron high

D. Lagarde, A. Balocchi, P. Renucci, H. Carrère

The carrier spin dynamics in ZnO is investigated by time-resolved optical orientation experiments. We evidence a clear circular polarization of the donor-bound exciton luminescence in both ZnO epilayer and non-intentionally doped bulk ZnO. This allows us to measure the localized hole spin relaxation time. We find $τ^{s}_h$$\sim$350 ps at T=1.7 K in the ZnO e

Florentin Millour

I try to present a small view of the properties and issues related to astronomical interferometry observations. I recall a bit of history of the technique, give some basic assessments to the principle of interferometry, and finally, describe physical processes and limitations that affect optical long baseline interferometry and which are, in general, very us

G. Quintana-Lacaci, V. Bujarrabal, A. Castro-Carrizo

The yellow hypergiant stars (YHGs) are very massive objects that are expected to pass through periods of intense mass loss during their evolution. Despite of this, massive circumstellar envelopes have been found only in two of them, IRC+10420 and AFGL 2343. The envelopes around these objects and the processes that form them are poorly known. We aim to study

T. Rauch, E. Reiff, K. Werner, J. W. Kruk

Spectral analyses of H-deficient post-AGB stars have shown that a small group of four extremely hot objects exists which have almost pure He absorption-line spectra in the optical. These are classified as O(He) stars. For their evolution there are two scenarios: They could be the long-sought hot successors of RCrB stars, which have not been identified up to

S. Monturet, N. Lorente

A time-dependent approach is used to explore inelastic effects during electron transport through few-level systems. We study a tight-binding chain with one and two sites connected to vibrations. This simple but transparent model gives insight about inelastic effects, their meaning and the approximations currently used to treat them. Our time-dependent approa

I. Eremin, G. Zwicknagl, P. Thalmeier, P. Fulde

We show that the recently observed spin resonance modes in heavy-fermion superconductors CeCoIn$_5$ and CeCu$_2$Si$_2$ are magnetic excitons originating from superconducting quasiparticles. The wave vector ${\bf Q}$ of the resonance state leads to a powerful criterion for the symmetry and node positions of the unconventional gap function. The detailed analys

Stephen Theriault

Cohen conjectured that for r>=2 there is a space T^2n+1(2^r) and a homotopy fibration sequence Loop^2 S^2n+1 --> S^2n-1 --> T^2n+1(2^r) --> Loop S^2n+1 with the property that the left map composed with the double suspension, Loop^2 S^2n+1 --> S^2n-1 --> Loop^2 S^2n+1, is homotopic to the 2^r-power map. We positively resolve this conjecture when r>=3. Several

Benoit Kloeckner

We study the Lipschitz structures on the geodesic compactification of a regular tree, that are preserved by the automorphism group. They are shown to be similar to the compactifications introduced by William Floyd, and a complete description is given.

Hernan L. Calvo, Horacio M. Pastawski

The time-reversal mirror (TRM) of acoustic waves is used as a focusing technique that is robust against disorder and chaos. The propagation of an ultrasonic pulse from the focal point is detected and recorded by a surrounding array of transducers that enclose the cavity region. The registered signals are then played-back in the reverse temporal sequence and

Jean Alexandre, Nick E. Mavromatos, Dylan Tanner

Conformal invariance for bosonic strings in time-dependent backgrounds of graviton, dilaton and Kalb-Ramond field is obtained by imposing Weyl-beta functions to be homogeneous in time, to all orders in $α^{&#39;}$. This construction is possible in any target space dimension, as a result of the non-trivial background configurations. The electromagnetic effect

J. T. Locsei, T. J. Pedley

Escherichia coli is a motile bacterium that moves up a chemoattractant gradient by performing a biased random walk composed of alternating runs and tumbles. This paper presents calculations of the chemotactic drift velocity vd (the mean velocity up the chemoattractant gradient) of an E. coli cell performing chemotaxis in a uniform, steady shear flow, with a

C. Romero-Redondo, E. Garrido, D. V. Fedorov, A. S. Jensen

We investigate to what extent a description of 12Be as a three-body system made of an inert 10Be-core and two neutrons is able to reproduce the experimental 12Be data. Three-body wave functions are obtained with the hyperspherical adiabatic expansion method. We study the discrete spectrum of 12Be, the structure of the different states, the predominant transi

A. Calle Cordon, E. Ruiz Arriola

We determine the mass and strength of the scalar meson from NN scattering data by renormalizing the One Boson Exchange Potential. This procedure provides a great insensitivity to the unknown short distance interaction making the vector mesons marginally important and allowing for SU(3) couplings in the 1S0 channel. The scalar meson parameters are tightly con

Lukasz Nitschke

Internet voting will probably be one of the most significant achievements of the future information society. It will have an enormous impact on the election process making it fast, reliable and inexpensive. Nonetheless, so far remote voting is considered to be very difficult, as one has to take into account susceptibility of the voter&#39;s PC to various cyb

Giuseppe Pucacco, Dino Boccaletti, Cinzia Belmonte

The phase-space structure of two families of galactic potentials is approximated with a resonant detuned normal form. The normal form series is obtained by a Lie transform of the series expansion around the minimum of the original Hamiltonian. Attention is focused on the quantitative predictive ability of the normal form. We find analytical expressions for b

Pabitra Pal Choudhury, Birendra Kumar Nayak, Sudhakar Sahoo, Sunil Pankaj Rath

This paper deals with the theory and application of 2-Dimensional, nine-neighborhood, null- boundary, uniform as well as hybrid Cellular Automata (2D CA) linear rules in image processing. These rules are classified into nine groups depending upon the number of neighboring cells influences the cell under consideration. All the Uniform rules have been found to

A. Torres-Rodriguez, C. M. Cress, K. Moodley

An interesting probe of the nature of dark energy is the measure of its sound speed, $c_s$. We review the significance for constraining sound speed models of dark energy using large neutral hydrogen (HI) surveys with the Square Kilometre Array (SKA). Our analysis considers the effect on the sound speed measurement that arises from the covariance of $c_s$ wit

Charilaos Efthymiou, Paul G. Spirakis

In this work we present a simple and efficient algorithm which, with high probability, provides an almost uniform sample from the set of proper k-colourings on an instance of a sparse random graph G(n,d/n), where k=k(d) is a sufficiently large constant. Our algorithm is not based on the Markov Chain Monte Carlo method (M.C.M.C.). Instead, we provide a novel

M. Albaladejo, J. A. Oller, C. Piqueras

We have performed a thorough study of the meson-meson S-waves with isospin (I) 0 and 1/2, up to sqrt(s) ~ 2 GeV. This is the first study that includes 13 channels that have their threshold below that energy. All the resonances below 2 GeV, namely the f_0(600) or sigma, f_0(980), f_0(1370), f_0(1500), f_0(1710) and f_0(1790) for I=0, and the K*_0(800) or kapp

Vladan Pankovic, Rade Glavatovic, Simo Ciganovic

In this work we suggest, without detailed mathematical analysis, a hypothesis on the physical meaning of cosmological constant. It is primarily based on a conceptual analogy with energy characteristics of the crystal lattice structure, i.e. energy zones theory in solid state physics. Namely, according to some theories (holographic principle, emergent gravity