December 2007 arXiv papers — page 15
Showing 1,401–1,500 of 4,627 papers
Brice Chung, Thierry Jolicoeur
In the limit of very fast rotation atomic Bose-Einstein condensates may reside entirely in the lowest two-dimensional Landau level (LLL). For small enough filling factor of the LLL, one may have formation of fractional quantum Hall states. We investigate the case of bosons with dipolar interactions as may be realized with Chromium-52 atoms. We show that at f
Mohammed Abouzaid, Paul Seidel
Liouville domains are a special type of symplectic manifolds with boundary (they have an everywhere defined Liouville flow, pointing outwards along the boundary). Symplectic cohomology for Liouville domains was introduced by Cieliebak-Floer-Hofer-Wysocki and Vitero. The latter constructed a restriction (or transfer) map associated to an embedding of one Liou
Application of afxy-code for parameterization of ionization yield function Y in the atmosphere for primary cosmic ray protons
physics.space-phL. Alexandrov, A. Mishev
In this work is obtained new approximation for the yield function Y for cosmic ray induced ionization in the Earth atmosphere on the basis of simulated data. The parameterization is obtained using inverse nonlinear problem solution with afxy(analyze fx=y)-code. Short description of the methods is given. The found approximation is for primary proton nuclei, i
Beom Hyun Kim, Unjong Yu, Kyoo Kim, B. I. Min
Employing the Monte-Carlo method and the exact diagonalization, we have investigated the temperature dependence of the thermoelectric power (TEP) for the double exchange model in the dilute carrier concentration limit. We have found that the TEP follows the Heikes formula in the high temperature regime, whereas, in the intermediate temperature regime, the TE
P. P. Kulish, N. Manojlovic, Z. Nagy
A reducible representation of the Temperley-Lieb algebra is constructed on the tensor product of n-dimensional spaces. One obtains as a centraliser of this action a quantum algebra (a quasi-triangular Hopf algebra) U_q with a representation ring equivalent to the representation ring of the sl_2 Lie algebra. This algebra U_q is the symmetry algebra of the cor
Debarati Chatterjee, Debades Bandyopadhyay
We investigate the hyperon bulk viscosity due to the non-leptonic process $n + p \rightleftharpoons p + Λ$ in $K^-$ condensed matter and its effect on the r-mode instability in neutron stars. We find that the hyperon bulk viscosity coefficient in the presence of antikaon condensate is suppressed compared with the case without the condensate. The suppressed h
Victor L. Chernyak
The dynamical scenario is considered for N=1 SQCD, with N_c colors and N_c<N_F<3N_c flavors with small but nonzero current quark masses m_Q\neq 0, in which quarks form the diquark-condensate phase. This means that colorless chiral quark pairs condense coherently in the vacuum, <{\bar Q}Q>\neq 0, while quarks alone don't condense, <Q>=<\bar Q>=0, so that
Neil Lambert
We discuss the low energy effective theory of an M5-brane wrapped on a smooth holomorphic four-cycle of K3 x T^2, including the special case of T^6. In particular we give the lowest order equations of motion and resolve a puzzle concerning the counting of massless modes that was reported in hep-th/9906094. In order to find agreement with black hole entropy a
A. Eckart, F. K. Baganoff, M. Zamaninasab, M. Morris
Stellar dynamics indicate the presence of a super massive 3-4x10^6 Msun solm black hole at the Galactic Center. It is associated with the variable radio, near-infrared, and X-ray counterpart Sagittarius A* (SgrA*). The goal is the investigation and understanding of the physical processes responsible for the variable emission from SgrA*. The observations have
Exciton spectra in vertical stacks of triple and quadruple quantum dots in an electric field
cond-mat.mes-hallB. Szafran, E. Barczyk, F. M. Peeters, S. Bednarek
We study an electron-hole pair in a stack of multiple quantum dots in the presence of an external electric field using the configuration interaction approach. We find that the bright energy levels can be grouped into families which are associated with the hole localized in a specific dot of the stack. The exciton energy levels undergo avoided crossings as fu
Complementarity of Gamma-ray and LHC Searches for Neutralino Dark Matter in the Focus Point Region
astro-phE. Moulin, A. Jacholkowska, G. Moultaka, J. -L. Kneur
We study the complementarity between the indirect detection of dark matter with gamma-rays in H.E.S.S. and the supersymmetry searches with ATLAS at the Large Hadron Collider in the Focus Point region within the mSUGRA framework. The sensitivity of the central telescope of the H.E.S.S. II experiment with an energy threshold of ~ 20 GeV is investigated. We sho
Simon Roessner, Thomas Hell, Claudia Ratti, Wolfram Weise
The Polyakov loop extended Nambu and Jona-Lasinio model (PNJL model) in a mean field framework shows astonishingly good agreement with lattice QCD calculations which needs to be better understood. The present work reports on further developments concerning both Polyakov loop and mesonic fluctuations beyond mean field approximation. Corrections beyond mean fi
Enhanced Transmission of Light and Particle Waves through Subwavelength Nanoapertures by Far-Field Interference
physics.opticsS. V. Kukhlevsky
Subwavelength aperture arrays in thin metal films can enable enhanced transmission of light and matter (atom) waves. The phenomenon relies on resonant excitation and interference of the plasmon or matter waves on the metal surface. We show a new mechanism that could provide a great resonant and nonresonant transmission enhancement of the light or de Broglie
K. V. Stepanyantz
For the N=1 supersymmetric massless electrodynamics, regularized by higher derivatives, we describe a method, by which one can try to prove the new identity for the Green functions, which was proposed earlier. Using this method we show that some contribution to the new identity are really 0.
Pierre Lescanne
This paper presents experiments on common knowledge logic, conducted with the help of the proof assistant Coq. The main feature of common knowledge logic is the eponymous modality that says that a group of agents shares a knowledge about a certain proposition in a inductive way. This modality is specified by using a fixpoint approach. Furthermore, from these
M. Marklund, G. Brodin, L. Stenflo, C. S. Liu
Surface plasmon polaritons (SPPs) have recently been recognized as an important future technique for microelectronics. Such SPPs have been studied using classical theory. However, current state-of-the-art experiments are rapidly approaching nanoscales, and quantum effects can then become important. Here we study the properties of quantum SPPs at the interfac
Feng-Yu Wang
Let $P_t$ be the diffusion semigroup generated by $L:=Δ+\nabla V$ on a complete connected Riemannian manifold with $\operatorname {Ric}\ge-(σ^2ρ_o^2+c)$ for some constants $σ, c>0$ and $ρ_o$ the Riemannian distance to a fixed point. It is shown that $P_t$ is hypercontractive, or the log-Sobolev inequality holds for the associated Dirichlet form, provided $-\
C. Tello, T. Villela, S. Torres, M. Bersanelli
We present a partial-sky survey of the radio continuum at 2.3 GHz within the scope of the Galactic Emission Mapping (GEM) project, an observational program conceived and developed to reveal the large-scale properties of Galactic synchrotron radiation through a set of self-consistent surveys of the radio continuum between 408 MHz and 10 GHz. The GEM experimen
Franz Lehner, Markus Neuhauser, Wolfgang Woess
Let $G$ be a finitely generated group and $X$ its Cayley graph with respect to a finite, symmetric generating set $S$. Furthermore, let $H$ be a finite group and $H \wr G$ the lamplighter group (wreath product) over $G$ with group of "lamps" $H$. We show that the spectral measure (Plancherel measure) of any symmetric "switch--walk--switch" ra
Bertil Nistad, Johannes Skaar
Several results concerning active media or metamaterials are proved and discussed. In particular, we consider the permittivity, permeability, wave vector, and refractive index, and discuss stability, refraction, gain, and fundamental limitations resulting from causality.
K. M. Doebrich, M. Wietstruk, J. E. Prieto, F. Heigl
For epitaxial trilayers of the magnetic rare-earth metals Gd and Tb, exchange coupled through a non-magnetic Y spacer layer, element-specific hysteresis loops were recorded by the x-ray magneto-optical Kerr effect at the rare-earth $M_5$ thresholds. This allowed us to quantitatively determine the strength of interlayer exchange coupling (IEC). In addition to
Yi-Xin Chen, Yong Xiao
By collecting both quantum and gravitational principles, a space-time uncertainty relation $(δt)(δr)^{3}\geqslantπr^{2}l_{p}^{2}$ is derived. It can be used to facilitate the discussion of several profound questions, such as computational capacity and thermodynamic properties of the universe and the origin of holographic dark energy. The universality and val
Near Fermi level Electronic Structure of Pr$_{1-x}$Sr$_x$MnO$_3$: Photoemission Study
cond-mat.str-elP. Pal, M. K. Dalai, R. Kundu, M. Chakraborty
In this study, we report the observation of a pseudogap associated with the insulator-metal transition in compositions of Pr$_{1-x}$Sr$_x$MnO$_3$ system with no charge ordering. Our valence band photoemission study shows that the observed shifts in the near Fermi level density of states are abrupt at the Curie transtion and occur over an energy scale of $\si
Generalized Hasimoto Transform of One-Dimensional Dispersive Flows into Compact Riemann Surfaces
math.APEiji Onodera
We study the structure of differential equations of one-dimensional dispersive flows into compact Riemann surfaces. These equations geometrically generalize two-sphere valued systems modeling the motion of vortex filament. We define a generalized Hasimoto transform by constructing a good moving frame, and reduce the equation with values in the induced bundle
Philippe Choquard, Joachim Stubbe, Marc Vuffray
We prove the existence and uniqueness of stationary spherically symmetric positive solutions for the Schrödinger-Newton model in any space dimension $d$. Our result is based on an analysis of the corresponding system of second order differential equations. It turns out that $d=6$ is critical for the existence of finite energy solutions and the equations for
Sergei M. Kuzenko, Gabriele Tartaglino-Mazzucchelli
This paper is a companion to our earlier work arXiv:0710.3440 in which the projective superspace formulation for matter-coupled simple supergravity in five dimensions was presented. For the minimal multiplet of 5D N=1 supergravity introduced by Howe in 1981, we give a complete solution of the Bianchi identities. The geometry of curved superspace is shown to
Chas A. Egan, Charles H. Lineweaver
Dynamic dark energy (DDE) models are often designed to solve the cosmic coincidence (why, just now, is the dark energy density $ρ_{de}$, the same order of magnitude as the matter density $ρ_m$?) by guaranteeing $ρ_{de} \sim ρ_m$ for significant fractions of the age of the universe. This typically entails ad-hoc tracking or oscillatory behaviour in the model.
Mass hierarchy, mass gap and corrections to Newton's law on thick branes with Poincare symmetry
hep-thNandinii Barbosa-Cendejas, Alfredo Herrera-Aguilar, Konstantinos Kanakoglou, Ulises Nucamendi
We consider a scalar thick brane configuration arising in a 5D theory of gravity coupled to a self-interacting scalar field in a Riemannian manifold. We start from known classical solutions of the corresponding field equations and elaborate on the physics of the transverse traceless modes of linear fluctuations of the classical background, which obey a Schro
Sunandan Gangopadhyay
We exploit the expression for the anomalous (chiral) effective action to obtain the Hawking radiation from the GHS (stringy) blackhole falling in the class of the most general spherically symmetric blackholes $(\sqrt{-g}\neq1)$, using only covariant boundary condition at the event horizon. The connection between the anomalous and the normal energy-momentum t
Tomasz Maszczyk
It is shown that for every splitting of a polynomial with noncommutative coefficients into linear factors $(X-a_{k})$ with $a_{k}$'s commuting with coefficients, any cyclic permutation of linear factors gives the same result and all $a_{k}$ are roots of that polynomial. Examples are given and analyzed from Galois theory point of view.
Jian Zhai
Limit behaviors of blow up solutions for impressible Navier-Stokes equations are obtained.
Patrick Berghaus, Teresa Montaruli, Johannes Ranft
In this work, charm production in the {\sc dpmjet} hadronic jet simulation is compared to experimental data. Since the major application of {\sc dpmjet} is the simulation of cosmic ray-induced air showers, the version of the code integrated in the CORSIKA simulation package has been used for the comparison. Wherever necessary, adjustments have been made to i
Wavefunction considerations for the central spin decoherence problem in a nuclear spin bath
cond-mat.mes-hallW. M. Witzel, S. Das Sarma
Decoherence of a localized electron spin in a solid state material (the ``central spin'' problem) at low temperature is believed to be dominated by interactions with nuclear spins in the lattice. This decoherence is partially suppressed through the application of a large magnetic field that splits the energy levels of the electron spin and prevents d
N. Gvozdenovic, M. Laurent, F. Vallentin
Lovasz and Schrijver, and later Lasserre, proposed hierarchies of semidefinite programming relaxations for general 0/1 linear programming problems. In this paper these two constructions are revisited and two new, block-diagonal hierarchies are proposed. They have the advantage of being computationally less costly while being at least as strong as the Lovasz-
Vadim Zaliva
Portable Electronic Devices usually utilize a small screen with limited viewing area and a keyboard with a limited number of keys. This makes it difficult to perform quick searches in data arrays containing more than dozen items such an address book or song list. In this article we present a new data selection method which allows the user to quickly select a
J. Alwall, E. Boos, L. Dudko, M. Gigg
We propose to combine and slightly extend two existing "Les Houches Accords" to provide a simple generic interface between beyond-the-standard-model parton-level and event-level generators. All relevant information - particle content, quantum numbers of new states, masses, cross sections, parton-level events, etc - is collected in one single file, wh
A. Yu. Smirnov, S. Savel'ev, L. G. Mourokh, Franco Nori
We examine the dynamics of biological nanomotors within a simple model of a rotor having three ion-binding sites. It is shown that in the presence of an external dc electric field in the plane of the rotor, the loading of the ion from the positive side of a membrane (rotor charging) provides a torque leading to the motor rotation. We derive equations for the
Krzysztof Belczynski, K. Z. Stanek, Chris L. Fryer
We investigate the effect of including a significant ``binary twin'' population (binaries with almost equal mass stars, q = M2/M1 > 0.95) for the production of double compact objects and some resulting consequences, including LIGO inspiral rate and some properties of short-hard gamma-ray bursts. We employ very optimistic assumptions on the twin fract
A comparison of sexual and asexual replication strategies in a simplified model based on the yeast life cycle
q-bio.PEEmmanuel Tannenbaum
This paper develops simplified mathematical models describing the mutation-selection balance for the asexual and sexual replication pathways in {\it Saccharomyces cerevisiae}. We assume diploid genomes consisting of two chromosomes, and we assume that each chromosome is functional if and only if its base sequence is identical to some master sequence. The gro
The Spitzer Gould Belt Survey of Large Nearby Interstellar Clouds: Discovery of a Dense Embedded Cluster in the Serpens-Aquila Rift
astro-phR. A. Gutermuth, T. L. Bourke, L. E. Allen, P. C. Myers
We report the discovery of a nearby, embedded cluster of young stellar objects, associated filamentary infrared dark cloud, and 4.5 micron shock emission knots from outflows detected in Spitzer/IRAC mid-infrared imaging of the Serpens-Aquila Rift obtained as part of the Spitzer Gould Belt Legacy Survey. We also present radial velocity measurements of the reg
Jie Kong, Truell W. Hyde, Jorge Carmona Reyes
Dust particles often form vertical chains due to the influence of the wakefield produced by the streaming ions in the plasma sheath. These particle chains are proving useful as a unique diagnostic tool for investigating the physics behind the basic properties of the ion wakefield within the plasma sheath. In this paper, an experimental method is presented fo
Masahiro Ibe, Ryuichiro Kitano
It has been more than twenty years since theorists started discussing supersymmetric model building/phenomenology. We review mechanisms of supersymmetry breaking/mediation and problems in each scenario. We propose a simple model to address those problems and discuss its phenomenology.
Jocelyne Troccaz
The author reviews the computer and robotic tools available to urologists to help in diagnosis and technical procedures. The first part concerns the contribution of robotics and presents several systems at various stages of development (laboratory prototypes, systems under validation or marketed systems). The second part describes image fusion tools and navi
Dragomir Radev, Mark Hodges, Anthony Fader, Mark Joseph
The Clair library is intended to simplify a number of generic tasks in Natural Language Processing (NLP), Information Retrieval (IR), and Network Analysis. Its architecture also allows for external software to be plugged in with very little effort. Functionality native to Clairlib includes Tokenization, Summarization, LexRank, Biased LexRank, Document Cluste
Denis-Charles Cisinski, Frédéric Déglise
We define model category structures on the category of chain complexes over a Grothendieck abelian category depending on the choice of a generating family, and we study their behaviour with respect to tensor products and stabilization. This gives convenient tools to construct and understand triangulated categories of motives and we consider here the case of
High performance NbN nanowire superconducting single photon detectors fabricated on MgO substrates
physics.opticsF. Marsili, D. Bitauld, A. Fiore, A. Gaggero
We demonstrate high-performance nanowire superconducting single photon detectors (SSPDs) on ultrathin NbN films grown at a temperature compatible with monolithic integration. NbN films ranging from 150nm to 3nm in thickness were deposited by dc magnetron sputtering on MgO substrates at 400C. The superconducting properties of NbN films were optimized studying
Serena Criscuoli
We investigate, by numerical simulations, the photometric signature of magnetic flux tubes in the solar photosphere. We show that the observed contrast profiles are determined not only by the physical properties of the tube and its surroundings, but also by the peculiarities of the observations, including the line/continuum formation height and the spatial a
Xinghua Deng, Robert V. Moody
The paper studies the relationship between diffraction and dynamics for uniformly discrete ergodic point processes in real spaces. This relationship takes the form of an isometric embedding of two L^2 spaces. Diffraction (or equivalently the 2-point correlations) usually cannot determine the dynamics entirely, but we prove that knowledge of all the higher co
Mustafa Cenk Gursoy
In this paper, the performance of signaling strategies with high peak-to-average power ratio is analyzed over both coherent and noncoherent fading channels. Two modulation schemes, namely on-off phase-shift keying (OOPSK) and on-off frequency-shift keying (OOFSK), are considered. Initially, uncoded systems are analyzed. For OOPSK and OOFSK, the optimal detec
M. V. Perel, I. V. Fialkovsky
We present a new complex non-stationary particle-like solution of the non-linear Klein-Gordon equation with several spatial variables. The construction is based on reduction to an ordinary differential equation.
J. H. Debes, A. J. Weinberger, G. Schneider
We combine HST/NICMOS imaging photometry of the HR 4796A disk at previously unobserved wavelengths between 1.71-2.22\micron with reprocessed archival observations to produce a measure of the dust's scattering efficiency as a function of wavelength. The spectrum of the dust, synthesized from the seven photometric measures, is characterized by a steep red
Bifurcations of Free Thermal Vibrational Convection in Cylindrical Fluid Layer in Micro-Gravity: Numerical and Analytical Research
physics.flu-dynAlbert N. Sharifulin
The analysis of vibration effect on non-isothermal fluid in closed cavity is important for planning technological experiments in space. Control and optimization of these processes critically depend on the understanding of liquid response to the vibrations. With this aim the theoretical investigation for infinite plane and cylindrical fluid layers are perform
S. N. Storchak
The geometrical representation of the Jacobian in the path integral reduction problem which describes a motion of the scalar particle on a smooth compact Riemannian manifold with the given free isometric action of the compact semisimple Lie group is obtained. By using the formula for the scalar curvature of the manifold with the Kaluza--Klein metric, we pres
Mustafa Cenk Gursoy
In this paper, the capacity and energy efficiency of training-based communication schemes employed for transmission over a-priori unknown Rayleigh block fading channels are studied. In these schemes, periodically transmitted training symbols are used at the receiver to obtain the minimum mean-square-error (MMSE) estimate of the channel fading coefficients. I
Alex Pomarol, Andrea Wulzer
We show that skyrmions arising from compact five dimensional models have stable sizes. We numerically obtain the skyrmion configurations and calculate their size and energy. Although their size strongly depends on the magnitude of localized kinetic-terms, their energy is quite model-independent ranging between 50-65 times F_pi^2/m_rho, where F_pi is the Gold
Changsuk Noh, H. J. Carmichael
Disentanglement of a laser source from its target qubit is proposed as a criterion establishing the laser quantum state as a coherent state. It is shown that the source-target density operator has a unique factorization in coherent states when the environmental record monitoring laser pump quanta is ignored. The source-target state conditioned upon the compl
Houri Ziaeepour, Stephen T. Holland, Patricia T. Boyd, Kim L. Page
The early optical emission of the moderately high redshift ($z=3.08$) GRB 060607A shows a remarkable broad and strong peak with a rapid rise and a relatively slow power-law decay. It is not coincident with the strong early-time flares seen in the X-ray and gamma-ray energy bands. There is weak evidence for variability superposed on this dominant component in
J. Eberle, M. Cuntz, Z. E. Musielak
About half of all known stellar systems with Sun-like stars consist of two or more stars, significantly affecting the orbital stability of any planet in these systems. Here we study the onset of instability for an Earth-type planet that is part of a binary system. Our investigation makes use of previous analytical work allowing to describe the permissible re
Elizabeth Untiedt, Weldon Lodwick
Gradual numbers have been introduced recently as a means of extending standard interval computation methods to fuzzy intervals. The literature treats monotonic functions of fuzzy intervals. In this paper, we combine the concepts of gradual numbers and optimization, which allows for the evaluation of any differentiable function on fuzzy intervals, with no mon
Gregory F. Lawler
Some possible definitions for the natural parametrization of SLE (Schramm-Loewner evolution) paths are proposed in terms of various limits. One of the definitions is used to give a new proof of the Hausdorff dimension of SLE paths.
Marcin Bilski
Let {X_n} be a sequence of analytic sets converging to some analytic set X in the sense of holomorphic chains. We introduce a condition which implies that every irreducible component of X is the limit of a sequence of irreducible components of the sets from {X_n}. Next we apply the condition to approximate a holomorphic solution y=f(x) of a system Q(x,y)=0 o
M. Cuntz, L. Gurdemir, E. F. Guinan, R. L. Kurucz
We explore if carbon-based macromolecules (such as DNA) in the environments of stars other than the Sun are able to survive the effects of photospheric stellar radiation, such as UV-C. Therefore, we focus on main-sequence stars of spectral types F, G, K, and M. Emphasis is placed on investigating the radiative environment in the stellar habitable zones. Stel
Gregory F. Lawler
This is the first expository set of notes on SLE I have written since publishing a book two years ago [45]. That book covers material from a year-long class, so I cannot cover everything there. However, these notes are not just a subset of those notes, because there is a slight change of perspective. The main differences are: o I have defined SLE as a finite
Georgios Mountrichas, Tom Shanks
Prompted by indications from QSO lensing that there may be more mass associated with galaxy groups than expected, we have made new dynamical infall estimates of the masses associated with 2PIGG groups and clusters. We have analysed the redshift distortions in the cluster-galaxy cross-correlation function as a function of cluster membership, cross-correlating
C. Barbieri, E. Caurier, K. Langanke, G. Martínez-Pinedo
The occurrence of a pygmy dipole resonance in proton rich Ar-32 and Ar-34 is studied using the unitary correlator operator method interaction Vucom, based on Argonne V18. Predictions from the random phase approximation (RPA) and the shell model in a no-core basis are compared. It is found that the inclusion of configuration mixing up to two-particle--two-hol
M. Ya. Amusia, A. S. Baltenkov, L. V. Chernysheva
It is demonstrated that in photoabsorption by endohedral atoms some atomic Giant resonances are almost completely destroyed while the others are totally preserved due to different action on it of the fullerenes shell. As the first example we discuss the 4d10 Giant resonance in Xe@C60 whereas as the second serves the Giant autoionization resonance in Eu@C60.
E. Podlewska, E. Szuszkiewicz
In this paper we investigate the evolution of a pair of interacting planets - a Jupiter mass planet and a Super-Earth with the 5.5 Earth masses - orbiting a Solar type star and embedded in a gaseous protoplanetary disc. We focus on the effects of type I and II orbital migrations, caused by the planet-disc interaction, leading to the Super-Earth capture in fi
Samuel Boissiere, Etienne Mann, Fabio Perroni
We prove the cohomological crepant resolution conjecture of Ruan for the weighted projective space P(1,3,4,4). To compute the quantum corrected cohomology ring we combine the results of Coates-Corti-Iritani-Tseng on P(1,1,1,3) and our previous results.
Hideo Ohno, Tomasz Dietl
We describe recent progress and open questions in the physics of current-induced domain-wall displacement and creep in (Ga,Mn)As. Furthermore, the reasons are recalled why, despite strong disorder and localization, the p-d Zener model is suitable for the description of this system.
Extracting the Cosmological Constant from the Wheeler DeWitt Equation in a Modified Gravity Theory
gr-qcRemo Garattini
We discuss how to extract information about the cosmological constant from the Wheeler-DeWitt equation, considered as an eigenvalue of a Sturm-Liouville problem. A generalization to a f(R)theory is taken under examination. The equation is approximated to one loop with the help of a variational approach with Gaussian trial wave functionals. We use a zeta func
Singular asymptotic expansions for Dirichlet eigenvalues and eigenfunctions of the Laplacian on thin planar domains
math.SPDenis Borisov, Pedro Freitas
We consider the Laplace operator with Dirichlet boundary conditions on a planar domain and study the effect that performing a scaling in one direction has on the spectrum. We derive the asymptotic expansion for the eigenvalues and corresponding eigenfunctions as a function of the scaling parameter around zero. This method allows us, for instance, to obtain a
M. Chakraborty, P. Pal, B. R. Sekhar
In this communication we present a first principle study of Pr$_{1-x}$Sr$_{x}$MnO$_3$ with $x = 0.25$. While the parent compounds of this system are antiferromagnetic insulators with different structural and magnetic ground states, the $x = 0.25$ is in the colossal magnetoresistance regime of the Pr$_{1-x}$Sr$_{x}$MnO$_3$ phase diagram [C. Martin, A. Maignan
Daniel Sudarsky
We offer a critical assessment of some generic features of various of the current approaches towards the construction of a Theory of Quantum Gravity. We will argue that there is a need for further conceptual clarifications before such an enterprise can be launched on a truly well grounded setting, and that one of the guiding principles that can be viewed as
G. Venketeswara Pai, E. Shimshoni, N. Andrei
We study the contribution of quantum phase fluctuations in the superconducting order parameter to the low--temperature resistivity $ρ(T)$ of a dirty and inhomogeneous superconducting wire. In particular, we account for random spatial fluctuations of arbitrary size in the wire thickness. For a typical wire thickness above the critical value for superconductor
Achamveedu Gopakumar
Compact binaries inspiralling along quasi-circular orbits are the most plausible gravitational wave (GW) sources for the operational, planned and proposed laser interferometers. We provide new class of restricted post-Newtonian accurate GW templates for non-spinning compact binaries inspiralling along PN accurate quasi-circular orbits. Arguments based on dat
Rahim Moosa, Ruxandra Moraru, Matei Toma
It is shown that if $X$ is an Inoue surface of type $S_M$ then the irreducible components of the Douady space of $X^n$ are compact, for all $n>0$. This gives an example of an essentially saturated compact complex manifold (in the sense of model theory) that is not of Kaehler-type. Among the known compact complex surfaces without curves, it is shown that thes
Paul Doukhan, Olivier Wintenberger
We prove the existence of a weakly dependent strictly stationary solution of the equation $ X_t=F(X_{t-1},X_{t-2},X_{t-3},...;ξ_t)$ called {\em chain with infinite memory}. Here the {\em innovations} $ξ_t$ constitute an independent and identically distributed sequence of random variables. The function $F$ takes values in some Banach space and satisfies a Lip
Luen-Chau Li
In this paper, we investigate the long time behaviour for a class of low-regularity solutions of the Camassa-Holm equation given by the superposition of infinitely many interacting traveling waves with corners at their peaks.
Ian B. Thompson, Inese I. Ivans, Sara Bisterzo, Christopher Sneden
A detailed high-resolution spectroscopic analysis is presented for the carbon-rich low metallicity Galactic halo object CS 22964-161. We have discovered that CS 22964-161 is a double-lined spectroscopic binary, and have derived accurate orbital components for the system. From a model atmosphere analysis we show that both components are near the metal-poor ma
Harvey S. Reall
The Bekenstein-Hawking entropy of an extremal vacuum black ring is derived from a microscopic counting of states. The entropy of extremal Kaluza-Klein black holes with ergospheres is also derived.
Pedro J. Salas
CSS codes are a subfamily of stabilizer codes especially appropriate for fault-tolerant quantum computations. A very simple method is proposed to encode a general qudit when a Calderbank-Shor-Steane quantum code, defined over a q-ary alphabet, is used.
A. Sapar, A. Aret, L. Sapar, R. Poolamäe
We propose a new method for determination of element abundances in stellar atmospheres aimed for the automatic processing of high-quality stellar spectra. The pan-spectral method is based on weighted cumulative line-widths Q of studied element. Difference in quantities Q found from synthetic and observed spectra gives a correction to the initial abundance. F
Michael Gurstein
Community Informatics (CI) is the application of information and communications technologies (ICTs) to enable community processes and the achievement of community objectives. CI goes beyond the "Digital Divide" to making ICT access usable and useful to excluded populations and communities for local economic development, social justice, and political
Francois Delarue, Frédéric Lagoutière
We provide a probabilistic analysis of the upwind scheme for multi-dimensional transport equations. We associate a Markov chain with the numerical scheme and then obtain a backward representation formula of Kolmogorov type for the numerical solution. We then understand that the error induced by the scheme is governed by the fluctuations of the Markov chain a
L'accessibilité des E-services aux personnes non-voyantes : difficultés d'usage et recommandations
cs.HCFrançoise Sandoz-Guermond, Marc-Eric Bobiller-Chaumon
While taking into account handicapped people in the design of technologies represents a social and political stake that becomes important (in particular with the recent law on equal rights for all the citizens, March 2004), this paper aims at evaluating the level of accessibility of two sites of E-services thanks to tests of use and proposing a set of recomm
M. S. Hussein, J. X. de Carvalho, M. P. Pato, A. J. Sargeant
A random matrix model to describe the coupling of $m$-fold symmetry is constructed. The particular threefold case is used to analyze data on eigenfrequencies of elastomechanical vibration of an anisotropic quartz block. It is suggested that such experimental/theoretical study may supply a powerful means to discern intrinsic symmetry of physical systems.
J. Irving, A. Rattan
We count the number of lattice paths lying under a cyclically shifting piecewise linear boundary of varying slope. Our main result extends well known enumerative formulae concerning lattice paths, and its derivation involves a classical reflection argument. A refinement allows for the counting of paths with a specified number of corners. We also apply the re
M. H. van Kerkwijk, D. L. Kaplan
RX J1856.5-3754 is the X-ray brightest among the nearby isolated neutron stars. Its X-ray spectrum is thermal, and is reproduced remarkably well by a black-body, but its interpretation has remained puzzling. One reason is that the source did not exhibit pulsations, and hence a magnetic field strength--vital input to atmosphere models--could not be estimated.
Bloch gain in dc-ac-driven semiconductor superlattices in the absence of electric domains
cond-mat.mes-hallTimo Hyart, Kirill N. Alekseev, Erkki V. Thuneberg
We study theoretically the feasibility of amplification and generation of terahertz radiation in dc-ac-driven semiconductor superlattices in the absence of electric domains. We find that if in addition to dc bias a strong THz pump field is applied, Bloch gain profile for a small THz signal can be achieved under conditions of positive static differential cond
H. J. Drescher, M. Strikman
We investigate the impact of very strong small x gluon fields in colliding nucleons at LHC energies on the interaction of valence quarks. We find that in the range of small impact parameters, which contribute significantly to the production of heavy new particles, several of the valence quarks receive large transverse momenta, exceeding 1 GeV/c. This results
Una Hwang, Robert Petre, Kathryn A. Flanagan
We report the detection and localization of X-ray emitting ejecta in the middle-aged Galactic supernova remnant Puppis A using five observations with the Suzaku X-ray Imaging Spectrometer to survey the eastern and middle portions of the remnant. A roughly 3' by 5', double-peaked region in the north center is found to be highly enriched in Si and othe
M. Orienti, D. Dallacasa
Aims: The ``bright'' High Frequency Peakers (HFPs) sample is a mixture of blazars and intrinsically small and young radio sources. We investigate the polarimetric characteristics of 45 High Frequency Peakers, from the ``bright'' HFP sample, in order to have a deeper knowledge of the nature of each object, and to construct a sample made of gen
Megumi Harada, Paul Selick
Let G be a compact Lie group and LG its associated loop group. The main result of this manuscript is a surjectivity theorem from the equivariant K-theory of a Hamiltonian LG-space onto the integral K-theory of its Hamiltonian LG-quotient. Our result is a K-theoretic analogue of previous work in rational Borel-equivariant cohomology of Bott, Tolman, and Weits
P. Falgari
I report on recent results for the total production cross section of the process e- e+ -> mu- nubar_mu u dbar X near the W-pair production threshold up to next-to-leading order in GammaW/MW alpha v^2 obtained in the framework of unstable-particle effective field theory. Remaining theoretical uncertainties and their impact on the experimental determination of
L. Jouve, A. S. Brun
The Sun is a magnetic star whose magnetism and cyclic activity is linked to the existence of an internal dynamo. We aim to understand the establishment of the solar magnetic 22-yr cycle, its associated butterfly diagram and field parity selection through numerical simulations of the solar global dynamo. Inspired by recent observations and 3D simulations that
D. Garcia-Sanchez, A. San Paulo, M. J. Esplandiu, F. Perez-Murano
Bending-mode vibrations of carbon nanotube resonator devices were mechanically detected in air at atmospheric pressure by means of a novel scanning force microscopy method. The fundamental and higher order bending eigenmodes were imaged at up to 3.1GHz with sub-nanometer resolution in vibration amplitude. The resonance frequency and the eigenmode shape of mu
Pierre Jop
We present simulations of granular flows in a modified Couette cell, using a continuum model recently proposed for dense granular flows. Based on a friction coefficient, which depends on an inertial number, the model captures the positions of the wide shear bands. We show that a smooth transition in velocity-profile shape occurs when increasing the height of
Harold Steinacker
Recent progress in the understanding of gravity on noncommutative spaces is discussed. A gravity theory naturally emerges from matrix models of noncommutative gauge theory. The effective metric depends on the dynamical Poisson structure, absorbing the degrees of freedom of the would-be U(1) gauge field. The gravity action is induced upon quantization.
D. Yu. Ivanov
We discuss exclusive vector meson electroproduction within the QCD collinear factorization framework. In Bjorken kinematics the amplitude factorizes in a convolution of the nonperturbative meson distribution amplitude and the generalized parton densities with the perturbatively calculable hard-scattering amplitudes, which are presently known to next-to-leadi
Roberto Artuso, Lucia Cavallasca, Giampaolo Cristadoro
We introduce a family of area-preserving maps representing a (non-trivial) two-dimensional extension of the Pomeau-Manneville family in one dimension. We analyze the long-time behavior of recurrence time distributions and correlations, providing analytical and numerical estimates. We study the transport properties of a suitable lift and use a probabilistic a