February 2005 arXiv papers — page 10

James Nolen, Matthew Rudd, Jack Xin

We prove the existence of Kolmogorov-Petrovsky-Piskunov (KPP) type traveling fronts in space-time periodic and mean zero incompressible advection, and establish a variational (minimization) formula for the minimal speeds. We approach the existence by considering limit of a sequence of front solutions to a regularized traveling front equation where the nonlin

Bulat N. Khabibullin

We set new dual problems for the weighted spaces of holomorphic functions of one variable in domains on the complex plane, namely: nontriviallity of a given space, description of zero sets, description of (non-)uniqueness sets, the representation of meromorphic functions as a quotient of holomorphic functions from a given space.

Bulat N. Khabibullin

The classical representation problem for a meromorphic function f in C^n, n>=1, consists in representing f as the quotient f=g/h of two entire functions g and h, each with logarithm of modulus majorized by a function as close as possible to the Nevanlinna characteristic. Here we introduce generalizations of the Nevanlinna characteristic and give a short surv

Michel Gros

Let X a proper smooth curve over the field of complex numbers. Localization of the Heisenberg algebra gives the algebra of global sections of the ring of differential operators on the Jacobian J of X. It seems natural to ask for same kind of relations over a characteristic p > 0 field replacing the Heisenberg algebra by its entire form. We propose a conjectu

Stefan Gerhold

We consider the following question: Which real sequences (a(n)) that satisfy a linear recurrence with constant coefficients are positive for sufficiently large n? We show that the answer is negative for both (a(n)) and (-a(n)), if the dominating characteristic roots in the representation of a(n) as a generalized power sum comprise either two pairs of conjuga

Jean-Paul Dufour

This paper has three objectives. First to recall the link between the classical Legendre-Fenschel transformation and a useful isomorphism between 1-jets of functions on a vector bundle and on its dual. As a particular consequence we obtain the classical isomorphism between the cotangent bundle of the tangent bundle $T^*TM$ and the tangent bundle of the cotan

Ismail Kombe

In this paper we establish sharp weighted Hardy type inequalities on the Carnot group with homogeneous dimension $Q\ge 3$.

A. Granville, P. Kurlberg

We consider the distribution of spacings between consecutive elements in subsets of Z/qZ where q is highly composite and the subsets are defined via the Chinese remainder theorem. We give a sufficient criterion for the spacing distribution to be Poissonian as the number of prime factors of q tends to infinity, and as an application we show that the value set

Vestislav Apostolov, Christina W. Tønnesen-Friedman

We point out how some recent developments in the theory of constant scalar curvature Kähler metrics can be used to clarify the existence issue for such metrics in the special case of geometrically ruled complex surfaces.

Greg Martin, Kevin O'Bryant

We give explicit constructions of sets S with the property that for each integer k, there are at most g solutions to k=s_1+s_2, s_i\in S; such sets are called Sidon sets if g=2 and generalized Sidon sets if g\ge 3. We extend to generalized Sidon sets the Sidon-set constructions of Singer, Bose, and Ruzsa. We also further optimize Koulantzakis' idea of in

George Joseph McNinch

Let G be a semisimple group over an algebraically closed field of very good characteristic for G. In the context of geometric invariant theory, G. Kempf has associated optimal cocharacters of G to an unstable vector in a linear G-representation. If the nilpotent element X in Lie(G) lies in the image of the differential of a homomorphism SL(2) --> G, we say t

Anastasia Papavasiliou

In this paper, we study the problem of estimating a Markov chain $X$(signal) from its noisy partial information $Y$, when the transition probability kernel depends on some unknown parameters. Our goal is to compute the conditional distribution process ${\mathbb P}\{X_n|Y_n,...,Y_1\}$, referred to hereafter as the {\it optimal filter}. Following a standard Ba

Harald Ita, Harald Nieder, Yaron Oz

We consider type IIA/B strings in two-dimensions and their projection with respect to the nilpotent space-time supercharge. Based on the ground ring structure, we propose a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities. Depending on the type II spectra, one has either the conifold or the suspended

Gandalf Lechner

Starting from a given factorizing S-matrix $S$ in two space-time dimensions, we review a novel strategy to rigorously construct quantum field theories describing particles whose interaction is governed by $S$. The construction procedure is divided into two main steps: Firstly certain semi-local Wightman fields are introduced by means of Zamolodchikov's a

P A Horvathy, L. Martina, P. Stichel

The coupling of non-relativistic anyons (called exotic particles) to an electromagnetic field is considered. Anomalous coupling is introduced by adding a spin-orbit term to the Lagrangian. Alternatively, one has two Hamiltonian structures, obtained by either adding the anomalous term to the Hamiltonian, or by redefining the mass and the NC parameter. The mod

Sergey Shadchin

N=2 supersymmetric Yang-Mills theories for all classical gauge groups, that is, for SU(N), SO(N), and Sp(N) is considered. The formal expression for almost all models accepted by the asymptotic freedom are obtained. The equations which define the Seiberg-Witten curve are proposed. In some cases they are solved. It is shown that for all considered the 1-insta

Zhanna Kuznetsova, Francesco Toppan

We classify the admissible types of constraint (hermitian, holomorphic, with reality conditions on the bosonic sectors, etc.) for generalized supersymmetries in the presence of complex spinors. We further point out which constrained generalized supersymmetries admit a dual formulation. For both real and complex spinors generalized supersymmetries are constru

A. Albaid, M. S. Shikakhwa

The structure of the spin interaction operator (SI) (the interaction that remains after space variables are integrated out) in the first order S-matrix element of the elastic scattering of a Dirac particle in a general helicity-conserving vector potential is investigated.It is shown that the conservation of helicity dictates a specific form of the SI regardl

B. A. Kniehl, G. Kramer, I. Schienbein, H. Spiesberger

We present a detailed discussion of the collinear subtraction terms needed to establish a massive variable-flavour-number scheme for the one-particle inclusive production of heavy quarks in hadronic collisions. The subtraction terms are computed by convoluting appropriate partonic cross sections with perturbative parton distribution and fragmentation functio

John Ellis, Yitzhak Frishman

Two-dimensional QCD has often been used as a laboratory for studying the full four-dimensional theory, providing, for example, an explicit realization of baryons as solitons. We review aspects of conventional baryons in two-dimensional QCD, including the classical and quantum contributions to their masses. We then discuss the spectrum of exotic baryons in tw

K. R. S. Balaji, Jukka Maalampi

Ultra high energy cosmic ray (UHECR) neutrino fluxes measured in a fixed target detector can have a scale dependence. In the usual standard model or any extensions of this model (which are renormalizable), the effect is observationally very small. However, this need not be the case in models with extra-spatial dimensions, where the neutrino mass parameter ca

Raju Venugopalan

The Color Glass Condensate is a theory of the dynamical properties of partons in the Regge limit of QCD: x_{\rm Bj}\to 0$, $Q^2 >> Λ_{\rm QCD}^2={\rm fixed} and the center of mass energy squared s\to \infty. We provide a brief introduction to the theoretical ideas underlying the Color Glass Condensate and discuss the application of these ideas to high energy

Mannque Rho

The structure of the pentaquark baryon $Θ^+$ is discussed in terms of a $K^+$-skyrmion binding where the skyrmion arises as a soliton in hidden local symmetry approach to low-energy hadronic physics which may be considered as a holographic dual to QCD. The "vector manifestation" of chiral symmetry encoded in the effective theory Wilsonian-matched to

W. Bietenholz, S. Shcheredin

We present simulation results for lattice QCD with light pions. For the quark fields we apply chirally symmetric lattice Dirac operators, in particular the overlap hypercube operator, along with the standard overlap operator for comparison. This allows us to simulate at very low pion masses. The results are related to Random Matrix Theory and to Chiral Pertu

S. V. Sushkov

We extend the notion of phantom energy--which is generally accepted for homogeneously distributed matter with $w<-1$ in the universe--on inhomogeneous spherically symmetric spacetime configurations. A spherically symmetric distribution of phantom energy is shown to be able to support the existence of static wormholes. We find an exact solution describing a s

Lorenzo Iorio

In this paper we investigate the opportunities offered by the new Earth gravity models from the dedicated CHAMP and, especially, GRACE missions to the project of measuring the general relativistic Lense-Thirring effect with a new Earth&#39;s artificial satellite. It turns out that it would be possible to abandon the stringent, and expensive, requirements on

Kathrin Konczak, Thomas Linke, Torsten Schaub

We investigate the usage of rule dependency graphs and their colorings for characterizing and computing answer sets of logic programs. This approach provides us with insights into the interplay between rules when inducing answer sets. We start with different characterizations of answer sets in terms of totally colored dependency graphs that differ in graph-t

L. L. Bonilla, M. Kindelan, J. B. Keller

Certain equations with integral constraints have as solutions time-periodic pulses of a field-like unknown while a current-like unknown oscillates periodically with time. A general asymptotic theory of this phenomenon, the generalized Gunn effect, has been found recently. Here we extend this theory to the case of nonlinearities having only one stable zero, w

J. M. Higbie, L. E. Sadler, S. Inouye, A. P. Chikkatur

Polarization-dependent phase-contrast imaging is used to spatially resolve the magnetization of an optically trapped ultracold gas. This probe is applied to Larmor precession of degenerate and nondegenerate spin-1 $^{87}$Rb gases. Transverse magnetization of the Bose-Einstein condensate persists for the condensate lifetime, with a spatial response to magneti

J. Benz, T. Fukui, A. Klümper, C. Scheeren

We present a study of the Drude weight $D(T)$ of the spin-1/2 $XXZ$ chain in the gapless regime. The thermodynamic Bethe ansatz (TBA) is applied in two different ways. In the first application we employ the particle basis of magnons and their bound states. In this case we rederive and considerably extend earlier work in the literature. However, in the course

Gunnar Moller, Steven H. Simon

The method of Jain and Kamilla [PRB {\bf 55}, R4895 (1997)] allows numerical generation of composite fermion trial wavefunctions for large numbers of electrons in high magnetic fields at filling fractions of the form nu=p/(2mp+1) with m and p positive integers. In the current paper we generalize this method to the case where the composite fermions are in an

D. Alfè, M. Alfredsson, J. Brodholt, M. J. Gillan M. D. Towler

We report diffusion Monte Carlo (DMC) calculations on MgO in the rock-salt and CsCl structures. The calculations are based on Hartree-Fock pseudopotentials, with the single-particle orbitals entering the correlated wave function being represented by a systematically convergeable cubic-spline basis. Systematic tests are presented on system-size errors using p

Carsten Marr, Marc-Thorsten Huett

We study the effect of topology variation on the dynamic behavior of a system with local update rules. We implement one-dimensional binary cellular automata on graphs with various topologies by formulating two sets of degree-dependent rules, each containing a single parameter. We observe that changes in graph topology induce transitions between different dyn

Dipti Banerjee

The angular momentum of the Hall particles acquiring Berry phases from quantization,is the very source of unifying the physics of IQHE and FQHE. The origin of {\it Shift} quantum number lies in the change of angular momentum of the Hall particles from higher to lower Landau level. Here the non-vanishing effect of {\it Shift} in 2D has been evaluated in the f

J. Kinast, A. Turlapov, J. E. Thomas

We measure the temperature dependence of the radial breathing mode in an optically trapped, strongly-interacting Fermi gas of $^6$Li, just above the center of a broad Feshbach resonance. The frequency remains close to the unitary hydrodynamic value, while the damping rate reveals transitions at two well-separated temperatures, consistent with the existence o

V. S. Stepanyuk, L. Niebergall, W. Hergert, P. Bruno

The state of the art ab initio calculations of quantum mirages,the spin-polarization of surface-state electrons and the exchange interaction between magnetic adatoms in Cu and Co corrals on Cu(111) are presented. We find that the spin-polarization of the surface-state electrons caused by magnetic adatoms can be projected to a remote location and can be stron

F. da Cruz, F. Lechenault, O. Dauchot, E. Bertin

We investigate experimentally within a two-dimensional cell the distribution of the free volume associated either to single grains or to clusters of grains. Our main result is that the logarithm of the probability to find a free volume per grain v_N^f in a cluster of N grains scales as N^alpha g(v_N^f), with alpha = 0.75. We interpret this non extensive scal

Alexei Kolezhuk, Temo Vekua

It is shown that an external magnetic field applied to a spin-S isotropic zigzag chain induces a phase with spontaneously broken parity, characterized by long range ordering of vector chirality. This is in contrast to the two-component Luttinger liquid scenario proposed in the literature. Relevance to real materials is discussed.

J. Kong, B. J. LeRoy, S. G. Lemay, C. Dekker

We have developed a fabrication process for incorporating a gate electrode into suspended single-walled carbon nanotube structures for scanning tunneling spectroscopy studies. The nanotubes are synthesized by chemical vapor deposition directly on a metal surface. The high temperature ~800 C involved in the growth process poses challenging issues such as surf

Colm Connaughton, Christophe Josserand, Antonio Picozzi, Yves Pomeau

We study the formation of a large-scale coherent structure (a condensate) in classical wave equations by considering the defocusing nonlinear Schrödinger equation as a representative model. We formulate a thermodynamic description of the condensation process by using a wave turbulence theory with ultraviolet cut-off. In 3 dimensions the equilibrium state und

Joanne N. Bright, Denis J. Evans, Debra J. Searles

Deterministic thermostats are frequently employed in non-equilibrium molecular dynamics simulations in order to remove the heat produced irreversibly over the course of such simulations. The simplest thermostat is the Gaussian thermostat, which satisfies Gauss&#39;s principle of least constraint and fixes the peculiar kinetic energy. There are of course infi

C. Fusco, A. Fasolino

We present a comparative analysis of the velocity dependence of atomic-scale friction for the Tomlinson model, at zero and finite temperatures, in 1D and 2D, and for different values of the damping. Combining analytical arguments with numerical simulations, we show that an appreciable velocity dependence of the kinetic friction force $F_{fric}$, for small sc

B. N. J. Persson, U. Tartaglino, O. Albohr, E. Tosatti

Rubber friction on wet rough substrates at low velocities is typically 20-30% smaller than for the corresponding dry surfaces. We show that this cannot be due to hydrodynamics and propose a novel explanation based on a sealing effect exerted by rubber on substrate &#34;pools&#34; filled with water. Water effectively smoothens the substrate, reducing the majo

Y. Z. Zhang, Z. Wang

We make comments on the paper presented by Kim \textit{et al.} [Phys. Rev. B \textbf{61}, 11317 (2000)]. The authors analyzed activation energies of HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ thin films with a scaling relation, and defined four vortex regions for thin films. We find that the definitions of four vortex regions and the scaling relation are questionable whe

Akira Endo, Yasuhiro Iye

The amplitude V_0 of unidirectional periodic potential modulation introduced by a surface grating into a two-dimensional electron gas (2DEG) formed at AlGaAs/GaAs heterointerface is measured as a function of electron density n_e by analyzing commensurability oscillation of the magnetoresistance. The electron density is varied either by applying a bias to a m

Congjie Ou, Jincan Chen

Two important problems existing in Tsallis&#39; statistics are investigated, where one is whether energy is extensive or not, and the other is whether it is necessary to introduce the so-called generalized zeroth law of thermodynamics or not. The results obtained show clearly that like entropy, energy is also nonextensive in Tsallis&#39; statistics, and that

T. Muramatsu, N. Takeshita, C. Terakura, H. Takagi

High pressure effects on the superconducting transitions of beta-pyrochlore superconductors AOs2O6 (A = Cs, Rb, K) are studied by measuring resistivity under high pressures up to 10 GPa. The superconducting transition temperature Tc first increases with increasing pressure in all the compounds and then exhibits a broad maximum at 7.6 K (6 GPa), 8.2 K (2 GPa)

Jan H. Meinke, A. Alan Middleton

The energy landscape for the random-field Ising model (RFIM) is complex, yet algorithms such as the push-relabel algorithm exist for computing the exact ground state of an RFIM sample in time polynomial in the sample volume. Simulations were carried out to investigate the scaling properties of the push-relabel algorithm. The time evolution of the algorithm w

G. S. Uhrig, K. P. Schmidt, M. Grüninger

The universal behaviour of the magnetic excitations in high-temperature superconductors is described in a model with static stripes retaining only the localized spin degrees of freedom. The stripes are represented by a model of coupled two-leg spin ladders. We start from the results obtained previously by continuous unitary transformations for an isolated sp

Ivan Biaggio

This is a comment inspired by recently published results [Y. Zhang et al., Phys. Rev. Lett. 91, 157404 (2003)] that introduced the name &#34;amphoteric refraction&#34; for the fact that at the interface with an optically anisotropic material there can be a range of incidence angles for which the component of the Poynting vector parallel to the interface chan

V. N. Bogomolov

Properties of oxides are interpreted as a result of existence of the virtual sublattices formed by the atomic quantum states. An infinite cluster with the superconductivity of the Bose-Einstein condensate kind can be formed in the ground state sublattice at certain oxigen atoms concentration in the effectively diluted system of metal atoms (above the percola

Na Sai, Michael Zwolak, Giovanni Vignale, Massimiliano Di Ventra

Using time-dependent current-density functional theory, we derive analytically the dynamical exchange-correlation correction to the DC conductance of nanoscale junctions. The correction pertains to the conductance calculated in the zero-frequency limit of time-dependent density-functional theory within the adiabatic local-density approximation. In particular

Gregory Dobler, Charles R. Keeton

Flux ratio `anomalies&#39; in quadruply-imaged gravitational lenses can be explained with galactic substructure of the sort predicted by CDM, but the strength and uniqueness of that hypothesis needs to be further assessed. A good way to do that is to use the physical scale associated with the size of the source quasar, and its dependence on wavelength. We de

SuperCDMS Collaboration

WIMP-nucleon cross sections in the range 10^{-46} - 10^{-44} cm^2 may be probed by a ton-scale experiment with low energy thresholds and excellent discrimination of backgrounds. Because CDMS ZIP detectors are the most proven means of achieving such good discrimination, we intend to scale CDMS up to a ton detector mass. Development of this experiment, dubbed

Katia Cunha, Verne V. Smith

This study uses cool dwarfs as sources with which to probe fluorine abundances via HF. This molecule is detected for the first time in young K-M dwarf members of an OB association. Fluorine, oxygen, and carbon abundances were derived from the HF(1--0) R9 line along with samples of OH and CO vibration-rotation lines present in high-resolution infrared spectra

M. Vestergaard, B. M. Peterson

We study the low-contrast Fe II emission blends in the ultraviolet (1250--2200A) and optical (4000--6000A) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability of the optical Fe II emission is 50% - 75% that of Hbeta and th

Jacek Niemiec, Tomasz Bulik

We present Monte Carlo simulations of radiative transfer in magnetar atmospheres. We include the effects of vacuum polarization, electron and proton scattering, and free-free absorption. Simulations are performed for the atmosphere model with the magnetic field perpendicular and also tilted with respect to the neutron star surface, and we show that the avera

Edward W. Thommes

Young planets interact with their parent gas disks through tidal torques. An imbalance between inner and outer torques causes bodies of mass $\ga 0.1$ Earth masses to lose angular momentum and migrate inward rapidly relative to the disk; this is known as ``Type I&#39;&#39; migration. However, protoplanets that grow to gas giant mass, O($10^2) M_\oplus$, open

Russell J. Smith

We compute population synthesis models for the variation of H-alpha absorption indices (HaA and HaF), as a function of age and metallicity in old stellar systems. The models are based on the STELIB spectral library, and defined at resolution of 3 Angstrom FWHM. The indices are found to be highly sensitive to age variation, with only moderate response to meta

Giuseppe Lavagetto, Luciano Burderi, Francesca D&#39;Antona, Tiziana Di Salvo

We study the evolution of Low Mass X-ray Binaries (LMXBs) and of millisecond binary radio pulsars (MSPs), with numerical simulations that keep into account the evolution of the companion, of the binary system and of the neutron star. According to general relativity, when energy is released, the system loses gravitational mass. Moreover, the neutron star can

Magda Arnaboldi, Ortwin Gerhard, J. Alfonso L. Aguerri, Kenneth C. Freeman

Radial velocities of 40 intracluster planetary nebulae (ICPNe) in the Virgo cluster were obtained with the new multi-fiber FLAMES spectrograph on UT2 at VLT. For the first time, the lambda 4959 AA line of the [OIII] doublet is seen in a large fraction (50%) of ICPNe spectra, and a large fraction of the photometric candidates with m(5007) <\= 27.2 is spectros

J. A. L. Aguerri, O. E. Gerhard, M. Arnaboldi, N. R. Napolitano

We have investigated the properties of the diffuse light in the Virgo cluster core region, based on the detection of intracluster planetary nebulae (PNe) in four fields. We eliminate the bias from misclassified faint continuum objects, using improved Monte Carlo simulations, and the contaminations by high redshift Ly$α$ galaxies, using the Ly$α$ luminosity f

R. Salvaterra, B. Ciardi, A. Ferrara, C. Baccigalupi

We study CMB secondary anisotropies produced by inhomogeneous reionization by means of cosmological simulations coupled with the radiative transfer code CRASH. The reionization history is consistent with the WMAP Thomson optical depth determination. We find that the signal arising from this process dominates over the primary CMB component for l > 4000 and re

Marco Barden, Hans-Walter Rix, Rachel S. Somerville, Eric F. Bell

We combine HST imaging from the GEMS survey with photometric redshifts from COMBO-17 to explore the evolution of disk-dominated galaxies since z<1.1. The sample is comprised of all GEMS galaxies with Sersic indices n<2.5, derived from fits to the galaxy images. We account fully for selection effects through careful analysis of image simulations; we are limit

G. Perrin, S. T. Ridgway, T. Verhoelst, P. A. Schuller

Infrared interferometry of supergiant and Mira stars has recently been reinterpreted as revealing the presence of deep molecular layers. Empirical models for a photosphere surrounded by a simple molecular layer or envelope have led to a consistent interpretation of previously inconsistent data. The stellar photospheres are found to be smaller than previously

J. L. Innis, D. W. Coates, A. P. Borisova, M. K. Tsvetkov

Saturated stellar images on digitised photographic plates are many times greater in area than the `seeing disk&#39; seen in unsaturated CCD images. Indeed the flux profile of a bright star can be traced out for several degrees from the star&#39;s centre. The radius of the saturated stellar image can often be directly related to the magnitude of the star, a f

M. T. Rushton, T. R. Geballe, A. Evans, B. Smalley

We present moderate and high resolution infrared spectroscopy of the peculiar eruptive variable V838 Mon, which underwent a series of remarkable outbursts in early 2002. During the period covered by our observations, 2002 December-2003 December, the near-infrared spectrum continued to show many of the characteristics of a very cool supergiant. However, throu

Caroline van Breukelen, Matt J. Jarvis, Bram P. Venemans

We have used VIsible MultiObject Spectrograph Integral-Field Unit (VIMOS-IFU) observations centred on a radio galaxy at z=2.9 to search for Ly-alpha emitters within a comoving volume of ~ 10^4 Mpc^3. We find 14 Ly-alpha emitters with flux > 1.4 x 10^-20 Wm^-2, yielding a comoving space density of 0.0018 +/- 0.0006 Mpc^-3. We fit a Schechter luminosity functi

L. Morales-Rueda, T. R. Marsh, P. F. L. Maxted, G. Nelemans

We determine the orbits of four double degenerate systems (DDs), composed of two white dwarfs, and of two white dwarf -- M dwarf binaries. The four DDs, WD1022+050, WD1428+373, WD1824+040, and WD2032+188, show orbital periods of 1.157155(5) d, 1.15674(2) d, 6.26602(6) d and 5.0846(3) d respectively. These periods combined with estimates for the masses of the

T. J. T. Moore, S. L. Lumsden, N. A. Ridge, P. J. Puxley

We present a spectroscopic study of the shape of the dust-extinction law between 1.0 and 2.2um towards a set of nine ultracompact HII regions with Av > 15 mag. We find some evidence that the reddening curve may tend to flatten at higher extinctions, but just over half of the sample has extinction consistent with or close to the average for the interstellar m

A. Asensio Ramos, E. Landi Degl&#39;Innocenti, J. Trujillo Bueno

The theory of the generation and transfer of polarized radiation, mainly developed for interpreting solar spectropolarimetric observations, allows to reconsider, in a more rigorous and elegant way, a physical mechanism that has been suggested some years ago to interpret the high degree of polarization often observed in astronomical masers. This mechanism, fo

Volker Gaibler, Max Camenzind, Martin Krause

We study the effects of time-dependent mass injection and heating on the evolution of the interstellar medium (ISM) in elliptical galaxies. As the large and luminous ellipticals have supermassive black holes at their cores, which were probably much less massive in the young universe, feeding these black holes is essential. We examine steady state solutions a

I. D. Karachentsev, S. S. Kajsin, Z. Tsvetanov, H. Ford

We present new H-alpha imaging of all known dwarf irregular companions to NGC 6946: UGC 11583, KK 251, KK 252, KKR 55, KKR 56, Cepheus 1, KKR 59, and KKR 60. The galaxies span a range of blue absolute magnitudes of [-13.6, -17.6], relative gas content of [0.1, 2.5] M_sun/L_sun, current star formation activity of [0.2, 5.2]10^-2 M_sun yr^-1, and timescale to

M. Wals, B. J. Boyle, S. M. Croom, L. Miller

Co-addition of blank-field FIRST data at the location of over 8000 QSOs in the 2QZ survey has yielded statistical detections of radio quiet QSOs with median flux levels of 20-40microJy. We show that the total radio flux of radio-quiet QSOs in the 2QZ is consistent with a smooth extrapolation of the 2QZ radio-loud QSO number-flux distribution based on the slo

J. H. He

(Pseudo) radiative pumprate of OH 1612 MHz masers is defined for a sample of 44 OH/IR sources (infrared sources with OH 1612 MHz maser), irrespective of the real maser pumping mechanisms. The correlation between the (pseudo) maser pumprates and the evolutionary status of the maser sources reveals that the radiative pumprates of stellar OH masers are nearly f

P. Ruiz-Lapuente

Views on mechanics and cosmology by the observers of the supernova of 1572

A. Balastegui, P. Ruiz-Lapuente, J. Mendez, G. Altavilla

We discuss the expansion velocities of different elements in the ejecta of the intermediate-z SNe Ia discovered as a part of the International Time Programme (ITP) project ``Omega and Lambda from Supernovae and the Physics of Supernova Explosions&#39;&#39; at the European Northern Observatory (ENO). The expansion velocities measured for each normal SNIa are

Randall B. Wayth, Matthew O&#39;Dowd, Rachel L. Webster

We present spatially resolved spectroscopic images of the gravitationally lensed QSO 2237+0305 taken with the GMOS Integral Field Unit (IFU) on the Gemini North telescope. These observations have the best spatial resolution of any IFU observations of this object to date and include the redshifted CIII] and MgII QSO broad lines. Unlike Mediavilla et al. 1998,

E. F. del Peloso, L. da Silva, L. I. Arany-Prado

The purpose of this work is to resume investigation of Galactic thin disk dating using nucleocosmochronology with Th/Eu stellar abundance ratios, a theme absent from the literature since 1990. [Th/Eu] abundance ratios for a sample of 20 disk dwarfs/subgiants of F5 to G8 spectral type with -0.8 <= [Fe/H] <= +0.3, determined in the first paper of this series,

E. F. del Peloso, L. da Silva, G. F. Porto de Mello

The purpose of this work is to resume investigation of Galactic thin disk dating using nucleocosmochronology with Th/Eu stellar abundance ratios, a theme absent from the literature since 1990. A stellar sample of 20 disk dwarfs/subgiants of F5 to G8 spectral types with -0.8 <= [Fe/H] <= +0.3 was selected. In stars with such spectral types and luminosity clas

Richard Lieu

An analytical proof of the conservation of surface brightness during the strong and weak lensing of light by a singular isothermal sphere is provided. It is shown that the movement of asymptotic rays provide room for precisely the extra solid angle claimed by the magnification of the centrally passing rays. Previous claim of a violation of this conservation

Chiu-Chu Melissa Liu

Based on the duality between open-string theory on noncompact Calabi-Yau threefolds and Chern-Simons theory on three manifolds, M Marino and C Vafa conjectured a formula of one-partition Hodge integrals in term of invariants of the unknot (hep-th/0108064). Many Hodge integral identities, including the lambda_g conjecture and the ELSV formula, can be obtained

B. M. Gaensler, C. Kouveliotou, J. D. Gelfand, G. B. Taylor

Soft gamma repeaters (SGRs) are &#34;magnetars&#34;, a small class of slowly spinning neutron stars with extreme surface magnetic fields, ~10^15 gauss. On 2004 December 27, a giant flare was detected from the magnetar SGR 1806-20, the third such event ever recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric

C. Giardina&#39;, J. Kurchan

We introduce a family of Hamiltonian models for heat conduction with and without momentum conservation. They are analytically solvable in the high temperature limit and can also be efficiently simulated. In all cases Fourier law is verified in one dimension.

Rebecca Goldin, Tara S. Holm, Allen Knutson

We introduce the_inertial cohomology ring_ NH^*_T(Y) of a stably almost complex manifold carrying an action of a torus T. We show that in the case that Y has a locally free action by T, the inertial cohomology ring is isomorphic to the Chen-Ruan orbifold cohomology ring H_{CR}^*(Y/T) of the quotient orbifold Y/T. For Y a compact Hamiltonian T-space, we exten

M. Isse, A. Ohnishi, N. Otuka, P. K. Sahu

Collective flows in heavy-ion collisions from AGS ($(2-11)A$ GeV) to SPS ($(40,158)A$ GeV) energies are investigated in a nonequilibrium transport model with nuclear mean-field (MF). Sideward $<p_x>$, directed $v_1$, and elliptic flows $v_2$ are systematically studied with different assumptions on the nuclear equation of state (EOS). We find that momentum de

Leonhard Euler, Jordan Bell

Translated from the Latin original, &#34;Theorema arithmeticum eiusque demonstratio&#34;, Commentationes arithmeticae collectae 2 (1849), 588-592. E794 in the Enestroem index. For m distinct numbers a,b,c,d,...,\upsilon,x this paper evaluates \[ \frac{a^n}{(a-b)(a-c)(a-d)...(a-x)}+\frac{b^n}{(b-a)(b-c)(b-d)...(b-x)} +...+\frac{x^n}{(x-a)(x-b)(x-c)...(x-\upsi

C. Lunkes, C. Brukner, V. Vedral

We investigate multipartite entanglement in a non-interacting fermion gas, as a function of fermion separation, starting from the many particle fermion density matrix. We prove that all multiparticle entanglement can be built only out of two-fermion entanglement. Although from the Pauli exclusion principle we would always expect entanglement to decrease with

Mariangela Lisanti, Davide Iannuzzi, Federico Capasso

We have performed comparative measurements of the Casimir force between a metallic plate and a transparent sphere coated with metallic films of different thicknesses. We have observed that, if the thickness of the coating is less than the skin-depth of the electromagnetic modes that mostly contribute to the interaction, the force is significantly smaller tha

M. Forre, S. Selsto, J. P. Hansen, L. B. Madsen

The exact nondipole minimal-coupling Hamiltonian for an atom interacting with an explicitly time- and space-dependent laser field is transformed into the rest frame of a classical free electron in the laser field, i.e., into the Kramers-Henneberger frame. The new form of the Hamiltonian is used to study nondipole effects in the high-intensity, high-frequency

B. G. Sidharth

In recent years Quantum Superstrings and Quantum Gravity approaches have come to rely on non differenciable spacetime manifolds. These throw up a noncommutative spacetime geometry and we consider the origin of mass and a related modification of the Dirac equation in this context. This also throws some light on gravitation itself.

Z. V. Jaliashvili, T. D. Medoidze, Z. G. Melikishvili, K. M. Mardaleishvili

Laser illumination of tissue results in a characteristic fluorescence emission spectrum whose features depend on the type of tissue, viz., healthy, adenoma or malignant. Hence measurement of the fluorescence is potentially a rapid and reliable diagnostic method. We have applied the technique to thyroid tissues and found that judicious normalization of the fl

Vincenzo Galdi, Vincenzo Pierro, Giuseppe Castaldi, Innocenzo M. Pinto

The development of exotic new materials, such as metamaterials, has created strong interest within the electromagnetics (EM) community for possible new phenomenologies and device applications, with particular attention to periodicity-induced phenomena, such as photonic bandgaps (PBG). Within this context, motivated by the fairly recent discovery in X-ray cry

Gernot Greschonig, Ulrich Haboeck

In this paper we study topological cocycles for minimal homeomorphisms on a compact metric space. We introduce a notion of an essential range for topological cocycles with values in a locally compact group, and we show that this notion coincides with the well known topological essential range if the group is abelian. We define then a regularity condition for

Hitoshi Murakami

The volume conjecture and its generalization state that the series of certain evaluations of the colored Jones polynomials of a knot would grow exponentially and its growth rate would be related to the volume of a three-manifold obtained by Dehn surgery along the knot. In this paper, we show that for the figure-eight knot the series converges in some cases a

Aivars Berzins

In this paper is proved that the group of automorphisms of semigroup End(P[X]), if P is algebraically closed field, is generated by semi-inner automorphisms.

Aivars Berzins

In this paper, the problem formulated in [8] is solved. We prove, that the group of automorphisms of the category of free associative algebras is generated by semi-inner and mirror automorphisms

Stephane Grognet

The main result presented here is that the flow associated with a riemannian metric and a non zero magnetic field on a compact oriented surface without boundary, under assumptions of hyperbolic type, cannot have the same length spectrum of topologically corresponding periodic orbits as the geodesic flow associated with another riemannian metric having a nega

Julien Melleray

Answering a question of Gao and Kechris, we show that, given any polish group G, there exists a closed subset F of Urysohn&#39;s universal metric space U such that G is (topologically) isomorphic to the subgroup of isometries of U which map F onto itself.

V. Kreiman, V. Lakshmibai, P. Magyar, J. Weyman

We give an elementary and easily computable basis for the Demazure modules in the basic representation of the affine Lie algebra sl(n)-hat (and the loop group SL(n)-hat). A novel feature is that we define our basis ``bottom-up&#39;&#39; by raising each extremal weight vector, rather than ``top-down&#39;&#39; by lowering the highest weight vector. Our basis a