September 2003 arXiv papers — page 4

Lucjan Jacak, Piotr Sitko, Konrad Wieczorek, Arkadiusz Wójs

The book presents the wide range of topics in two-dimensional physics of quantum Hall systems, especially fractional quantum Hall states. It starts with the fundamental problems of quantum statistics in two dimensions and the corresponding braid group formalism. The braid group formalism of anyons (previously known) is developed for composite fermions. The m

A. Kaczanowski, K. Malarz, K. Kulakowski

Dynamics of nanoscopic arrays of monodomain magnetic elements is simulated by means of the Pardavi-Horvath algorithm. Experimental hysteresis loop is reproduced for the arrays of Ni, with the period 100 nm and the mean coercive field 710 Oe.We investigate the box-counting fractal dimension of a cluster of elements with given orientation of magnetic moments.

T. W. Heitmann, S. D. Bu, D. M. Kim, J. H. Choi

We report scanning tunneling spectroscopy (STS) measurements of the gap properties of both ceramic MgB2 and c-axis oriented epitaxial MgB2 thin films. Both show a temperature dependent zero bias conductance peak and evidence for two superconducting gaps. We report tunneling spectroscopy of superconductor-insulator-superconductor (S-I-S) junctions formed in t

Katsunori Wakabayashi, Kikuo Harigaya

We consider the electronic and magnetic properties of nanographite ribbon with zigzag edges under the periodic or Moebius boundary conditions. The zigzag nano-graphite ribbons possess edge localized states at the Fermi level which cause a ferrimagnetic spin polarization localized at the edge sites even in the very weak Coulomb interaction. The imposition of

Norman Murray, Joe Weingartner, Paul Capobianco

Micron size extrasolar dust particles have been convincingly detected by satellites. Larger extrasolar meteoroids (5-35 microns) have most likely been detected by ground based radar at Arecibo and New Zealand. We present estimates of the minimum detectable particle sizes and collecting areas for both radar systems. We show that particles larger than about 10

A. J. Castro-Tirado, J. Gorosabel, S. Guziy, D. Reverte

We present multiwavelength observations of a gamma-ray burst detected by INTEGRAL (GRB 030227) between 5.3 hours and ~1.7 days after the event. Here we report the discovery of a dim optical afterglow (OA) that would not have been detected by many previous searches due to its faintess (R~23). This OA was seen to decline following a power law decay with index

Robin Booth

A prediction of standard Big Bang cosmology is that the observed UHECR (ultra-high-energy cosmic rays) spectrum will exhibit a cutoff at the GKZ limit, resulting from interaction with the photons that constitute the cosmic microwave background. We show that for the Quasi-Static Universe (QSU) model, in which photon energy is an invariant in the cosmological

John J. Cowan, Christopher Sneden

During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of neutron-capture elements, improved astrophysical models, and increasingly more precise nuclear and atomic physics data. The e

Martin Durant, Marten H. van Kerkwijk, Ferdi Hulleman

The detection of optical/infrared counterparts to Anomalous X-ray Pulsars (AXPs) has greatly increased our understanding of these systems. Models for the AXP phenomenon were based upon their X-ray emission, and all but the magnetar model made predictions for the optical/infrared that have now been falsified. With detections in hand, detailed studies of the o

E. Kalemci, J. A. Tomsick, R. E. Rothschild, K. Pottschmidt

We characterize the evolution of spectral and temporal properties of several Galactic black hole transients during outburst decay using the data from well sampled PCA/\rxte observations close to the transition to the low/hard state. We find several global patterns of evolution for spectral and temporal parameters before, during, and after the transition. We

Dan Maoz, Avishay Gal-Yam

The iron mass in galaxy clusters is about 6 times larger than could have been produced by core-collapse supernovae (SNe), assuming the stars in the cluster formed with a standard initial mass function (IMF). SNe Ia have been proposed as the alternative dominant iron source. Different SN Ia progenitor models predict different ``delay functions'' betwe

Avishay Gal-Yam, Dan Maoz

We use the redshift distribution of type-Ia supernovae (SNe) discovered by the Supernova Cosmology Project to constrain the star formation history (SFH) of the Universe and SN Ia progenitor models. Given some of the recent determinations of the SFH, the observed SN Ia redshift distribution indicates a long (>~1 h^-1 Gyr) mean delay time between the formation

Andres Jordan, Patrick Cote, Michael J. West, Ronald O. Marzke

We have used WFPC2 on the Hubble Space Telescope to obtain F450W and F814W images of four cD galaxies (NGC 541 in Abell 194, NGC 2832 in Abell 779, NGC 4839 in Abell 1656 and NGC 7768 in Abell 2666) in the range 5400 < cz < 8100 km s^{-1}. For NGC 541, the HST data are supplemented by ground-based B and I images obtained with the FORS1 on the VLT. We present

Thomas Matheson

Observations of gamma-ray burst (GRB) afterglows have yielded tantalizing hints that supernovae (SNe) and GRBs are related. The case had been circumstantial, though, relying on irregularities in the light curve or the colors of the afterglow. I will present observations of the optical afterglow of GRB 030329. The early spectra show a power-law continuum, con

Regina E. Schulte-Ladbeck, Sandhya M. Rao, Igor O. Drozdovsky, David A. Turnshek

We report new imaging and spectroscopic observations of the damped Ly alpha (DLA) galaxy SBS 1543+593, a nearby dwarf galaxy whose stellar disk is intersected by the sightline to the bright background QSO HS 1543+5921. Hubble Space Telescope imaging observations with WFPC2 in the F450W and F702W bands are used to measure the DLA galaxy&#39;s properties and c

Myriam Gitti, Gianfranco Brunetti, Giancarlo Setti, Luigina Feretti

We apply to radio mini-halo candidates a model for electron re-acceleration in cooling flows (Gitti, Brunetti & Setti 2002). In agreement with the basic idea of the model, we find that the power required for the re-acceleration of the electron population is only a small fraction of the maximum power that can be extracted from the cooling flow (as estimated o

Orsola De Marco, A. F. Jones, M. J. Barlow, M. Cohen

Accumulating evidence points to a binary nature for the Wolf-Rayet ([WC]) central stars, a group that constitutes about 15% of all central stars of planetary nebula. From ISO observations, a dual dust chemistry (oxygen- and carbon-rich) has been shown to be almost exclusively associated with [WC] central stars, a fact that could be explained by O-rich dust r

I. M. Gioia, J. P. Henry, C. R. Mullis, H. Bohringer

The X-ray data around the North Ecliptic Pole (NEP) of the ROSAT All Sky Survey have been used to construct a contiguous area survey consisting of a sample of 445 individual X-ray sources above a flux of ~2x10^-14 erg cm^-2 s^-1 in the 0.5-2.0 keV energy band. The NEP survey is centered at RA (2000) = 18h 00m, DEC(2000) = +66deg 33arcmin and covers a region

A. A. Lundgren, T. Wiklind, H. Olofsson, G. Rydbeck

We present CO(1-0) and CO(2-1) Swedish-ESO Submillimetre Telescope (SEST) observations of the barred spiral galaxy M83 (NGC5236). The maps cover the entire optical disk. The CO emission is strongly peaked toward the nucleus, which breaks up into two separate components in the CO(2-1) data due to the higher spatial resolution. Emission from the bar is strong,

R. Tuellmann, M. R. Rosa, T. Elwert, D. J. Bomans

We present first deep VLT-spectra of a new class of compact extraplanar objects located in the disk-halo interface of the edge-on spiral galaxy NGC55. Their spectra reveal continuum emission from stars and show typical emission-lines as observed in ordinary disk HII-regions. Similar to the Diffuse Ionized Gas (DIG) the prominent ionization stage of oxygen is

L. A. Popa, C. Burigana, N. Mandolesi

We present constraints on the cosmological and reionization parameters based on the cumulative mass function of the Ly-alpha systems. We find that the analysis of the cumulative mass function of the Ly-alpha systems indicates a reionization redshift z_r=24.2\+-4 (68%CL) in agreement with the value found on the basis of the WMAP anisotropy measurements, setti

P. Kervella, F. Thevenin, P. Morel, J. Provost

Main Sequence (MS) stars are by far the most numerous class in the Universe. They are often somewhat neglected as they are relatively quiet objects (but exceptions exist), though they bear testimony of the past and future of our Sun. An important characteristic of the MS stars, particularly the solar-type ones, is that they host the large majority of the kno

Alfio Bonanno, Luciano Rezzolla, Vadim Urpin

We have investigated the turbulent mean-field dynamo action in protoneutron stars that are subject to convective and neutron finger instabilities. While the first one develops mostly in the inner regions of the star, the second one is favoured in the outer regions, where the Rossby number is much smaller and a mean-field dynamo action is more efficient. By s

H. Bravo-Alfaro, E. Brinks, A. J. Baker, F. Walter

We present VLA HI imaging of two blue compact dwarf (BCD) galaxies, Haro 2 and Haro 4, and of the spiral galaxy Haro 26, which is projected some 22&#39; SW of Haro 4. We also show a map of the CO(1-0) distribution of Haro 2 obtained with the OVRO millimeter array, as well as derive an upper limit for CO(2-1) emission from Haro 4 obtained with the CSO. The HI

M. Metz, M. Geffert

The accuracy of the link of the proper motion system of astrometric satellite missions like AMEX and GAIA is discussed. Monte-Carlo methods were used to simulate catalogues of positions and proper motions of quasars and galaxies to test the link. The main conclusion is, that future satellite missions like GAIA may be ``self-calibrated&#39;&#39; by their meas

Kunth Daniel

It now becomes possible to perform multiphase studies of the ISM from hot to molecular phases. HI and HII in star--forming gas-rich galaxies seem to exhibit differences in their metal composition in the sense that HII is less enriched in nitrogen, argon and possibly oxygen than the HII ionized gas. This observational evidence needs to be confirmed on larger

Maria-Rosa L. Cioni

Results obtained in the Magellanic Clouds using the latest near-IR DENIS survey are briefly revised. This sets the base to a similar study of AGB stars in other galaxies of the Local Group and in particular in NGC6822.

S. Hony, J. Bouwman

We investigate the dust composition of detached shells around carbon stars, with a focus to understand the origin of the cool magnesium-sulfide (MgS) material around warm carbon stars, which has been detected around several of these objects. We build a radiative transfer model of a carbon star surrounded by an expanding detached shell of dust. The shell cont

S. Campana, G. L. Israel, L. Stella, F. Gastaldello

Cen X-4 is one of the best studied low-mass neutron star transients in quiescence. Thanks to XMM-Newton large throughput, Cen X-4 was observed at the highest signal to noise ever. This allowed us to disclose rapid (>100 s), large (45+/-7 rms in the 10^{-4}-1 Hz range) intensity variability, especially at low energies. In order to highlight the cause of this

Raphael Hirschi, Georges Meynet, Andre Maeder, Stephane Goriely

The Geneva evolutionary code has been modified to study the advanced stages (Ne, O, Si burnings) of rotating massive stars. Here we present the results of four 20 solar mass stars at solar metallicity with initial rotational velocities of 0, 100, 200 and 300 km/s in order to show the crucial role of rotation in stellar evolution. As already known, rotation i

J. Gutierrez-Soto, J. Fabregat, J. Suso, A. M. Hubert

We present differential photometry of Be stars close to potential COROT primary targets for asteroseismology. Several stars are found to be short period variables. We propose them to be considered as secondary targets in the COROT asteroseismology fields.

F. A. Ringwald, J. M. Culver, R. L. Lovell, S. A. Kays

We present statistics on the research productivity of astronomical telescopes. These were compiled by finding papers in which new data were presented, noting which telescopes were used, and then counting the number of papers, number of pages, and other statistics. The journals used were the Astronomical Journal, the Astrophysical Journal (including the Lette

Klaus Dolag, Matthias Bartelmann, Francesca Perrotta, Carlo Baccigalupi

We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and compare them with &#34;standard&#39;&#39; Lambda-CDM and OCDM models. We find that previously proposed algorithms for predicting halo concentrations can be well a

Milan M. Cirkovic

It is argued that the tight interconnection between biological, climatological, and geophysical factors in the history of the terrestrial biosphere can teach us something of wider importance regarding the general astrobiological evolution of planets in the Galactic habitable zone of the Milky Way. Motivated by a recent debate on the future of Earth&#39;s bio

Milan M. Cirkovic

Classical arguments for skepticism regarding the Search for ExtraTerrestrial Intelligence (SETI) are critically examined. It is suggested that the emerging class of &#34;phase transition&#34; astrobiological models can simultaneously account for all available astrophysical and biological evidence, explain several unresolved puzzle in Earth sciences, and rati

S. Moehler, A. V. Sweigart, W. B. Landsman, S. Dreizler

Recent UV observations of the most massive Galactic globular clusters show a significant population of hot stars below the zero-age HB (``blue hook&#39;&#39; stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium-core flash while descending the whit

T. Wong, F. L. Schoeier, M. Lindqvist, H. Olofsson

We present radio-interferometric observations of HCN J=1-0 line emission from the carbon star R Scl, obtained with the interim 3-mm receivers of the Australia Telescope Compact Array. The emission is resolved into a central source with a Gaussian FWHM of ~1 arcsec, which we identify as the present mass loss envelope. Using a simple photodissociation model an

A. Lecavelier des Etangs, J. -M. Desert, D. Kunth, A. Vidal-Madjar

We present the analysis of FUSE observations of the metal-deficient dwarf galaxy IZw18. We measured column densities of HI, NI, OI, ArI, SiII, and FeII. The OI/HI ratio (log(OI/HI)=-4.7^{+0.8}_{-0.6}) is consistent with the O/H ratio observed in the HII regions (all uncertainties are 2-sigma). If the oxygen is depleted in the HI region compared to the HII re

G. Vladilo, L. Sbordone, P. Bonifacio

We compare chemical abundances of Local Group dwarf spheroidals, obtained from recent UVES/VLT observations, and of high redshift Damped Lyman alpha systems (DLAs), corrected for dust effects. We focus, in particular, on the abundance ratio between alpha-capture elements and iron, alpha/Fe, a well known indicator of chemical evolution. Comparison of the data

U. Lee

We study the $r$-modes propagating in steadily mass accreting, nuclear burning, and geometrically thin envelopes on the surface of rotating neutron stars. For the modal analysis, we construct the envelope models which are fully radiaitive or have a convective region. As the angular rotation frequency $Ω$ is increased, the oscillation frequency $ω$ of the $r$

J. S. Kaastra, T. Tamura, J. R. Peterson, J. A. M. Bleeker

We present spatially resolved X-ray spectra taken with the EPIC cameras of XMM-Newton of a sample of 17 cooling clusters and three non-cooling clusters for comparison. The deprojected spectra are analyzed with a multi-temperature model, independent of any a priori assumptions about the physics behind the cooling and heating mechanisms. All cooling clusters s

T. Boeker, M. Sarzi, D. E. McLaughlin, R. P. van der Marel

We investigate the structural properties of nuclear star clusters in late-type spiral galaxies. More specifically, we fit analytical models to HST images of 39 nuclear clusters in order to determine their effective radii after correction for the instrumental point spread function. We use the results of this analysis to compare the luminosities and sizes of n

Wolfgang Brandner

Over the past ten years, the concept of adaptive optics has evolved from early experimental stages to a standard observing tool now available at almost all major optical and near-infrared telescope facilities. Adaptive optics will also be essential in exploiting the full potential of the large optical/infrared interferometers currently under construction. Bo

A. S. Sakharov, H. Hofer

Cosmology is undergoing an explosive period of activity, fueled both by new, accurate astrophysical data and by innovative theoretical developments. Cosmological parameters such as the total density of the Universe and the rate of cosmological expansion are being precisely measured for the first time, and a consistent standard picture of the Universe is begi

Thomas Tradler, Mahmoud Zeinalian, Dennis Sullivan

We show that the complex $C_\bullet X$ of rational simplicial chains on a compact and triangulated Poincaré duality space $X$ of dimension $d$ is an A$_\infty$ coalgebra with $\infty$ duality. This is the structure required for an A$_\infty$ version of the cyclic Deligne conjecture. One corollary is that the shifted Hochschild cohomology $HH^{\bullet+d} (C^\

R. Leidl, W. Selke

Using Monte Carlo techniques, we show that the two--dimensional anisotropic Heisenberg model reproducing nicely inelastic neutron scattering measurements on La_5 Ca_9 Cu_24 O_41 (Matsuda et al. [Phys. Rev. B 68, 060406(R) (2003)]) seems to be insufficient to describe correctly measurements on thermodynamic quantities like the magnetization or the susceptibil

Thomas F. Jordan

The Friedmann equation is derived for a Newtonian universe. Changing mass density to energy density gives exactly the Friedmann equation of general relativity. Accounting for work done by pressure then yields the two Einstein equations that govern the expansion of the universe. Descriptions and explanations of radiation pressure and vacuum pressure are added

V. Hinich

Theorem 6.1.1 of [H.A.H.A.] on the existence of a model structure on the category of operads is not valid in the generality claimed. We present here a counter-example (due to B. Fresse) and a corrected version of the theorem.

Francis Bursa, Agustin Sabio Vera

We estimate the inclusive double diffractive production of SUSY particles at the LHC using a modified version of the POMWIG Monte Carlo event generator. The diffractive events are produced via the Ingelman-Schlein model for double pomeron exchange. The MSSM parameter space is scanned using the ``Snowmass benchmark points&#39;&#39; and it is shown that the li

B. Binz, D. Baeriswyl, B. Doucot

We present a general method to study weak-coupling instabilities of a large class of interacting electron models in a controlled and unbiased way. Quite generally, the electron gas is unstable towards a superconducting state even in the absence of phonons, since high-energy spin fluctuations create an effective attraction between the quasi-particles. As an e

Damiano Anselmi

As it stands, quantum gravity coupled with matter in three spacetime dimensions is not finite. In this paper I show that an algorithmic procedure that makes it finite exists, under certain conditions. To achieve this result, gravity is coupled with an interacting conformal field theory C. The Newton constant and the marginal parameters of C are taken as inde

Giovanni Felder, Alexander Varchenko

Elliptic Macdonald polynomials of sl(2)-type and level 2 are introduced. Suitable limits of elliptic Macdonald polynomials are the standard Macdonald polynomials and conformal blocks. Identities for elliptic Macdonald polynomials, in particular their modular properties, are studied.

Li Yang

We present a quantum no-key protocol for direct and secure transmission of quantum and classical messages based on simple Boolean function computation with several quantum gates and Shamir&#39;s interactive idea of classical message encryption. This protocol has inherent personal identification and message authentication. It probably is the first quantum pro

P. R. Berman

In light of experiments in atom optics, the compatibilty of negative refraction, perfect focusing with quantum mechanics is brought into question.

Guy Katriel

We study a modification of the canonical model for networks of class I neurons, presented by Hoppensteadt and Izhikevich, in which the &#39;pulse&#39; emitted by a neuron is smooth rather than a delta-function. We prove two types of results about synchronization and desynchronization of such networks, the first type pertaining to &#39;pulse&#39; functions wh

Ichiro Shimada

We show that every supersingular K3 surface is birational to a double cover of a projective plane.

Wei-Dong Ruan

In this paper we construct all smooth torus fibres of the generalized special Lagrangian torus fibrations for Calabi-Yau hypersurfaces in toric varieties near the large complex limit.

Nicolas Andruskiewitsch, Sonia Natale

We give the construction of a class of weak Hopf algebras (or quantum groupoids) associated to a matched pair of groupoids and certain cocycle data. This generalizes a now well-known construction for Hopf algebras, first studied by G. I. Kac in the sixties. Our approach is based on the notion of double groupoids, as introduced by Ehresmann.

Ken Dykema, Nate Strawn

We consider the space F^E_{k,n} of all spherical tight frames of k vectors in real or complex n--dimensional Hilbert space E^n, i.e. E=R or E=C, and its orbit space G^E_{k,n}=F^E_{k,n}/O^E_n under the obvious action of the group O^E_n of structure preserving transformations of E^n. We show that the quotient map F^E_{k,n} -> G^E_{k,n} is a locally trivial fib

Alain Connes, Henri Moscovici

We settle in this paper a question left open in our paper ``Modular Hecke algebras and their Hopf symmetry&#39;&#39;, by showing how to extend the Rankin-Cohen brackets from modular forms to modular Hecke algebras. More generally, our procedure yields such brackets on any associative algebra endowed with an action of the Hopf algebra of transverse geometry i

Hidekazu Furusho

Our main aim in this paper is to give a foundation of the theory of $p$-adic multiple zeta values. We introduce (one variable) $p$-adic multiple polylogarithms by Coleman&#39;s $p$-adic iterated integration theory. We define $p$-adic multiple zeta values to be special values of $p$-adic multiple polylogarithms. We consider the (formal) $p$-adic KZ equation a

Wei-Dong Ruan

In this paper we construct monodromy representing generalized special Lagrangian torus fibrations for Calabi-Yau hypersurfaces in toric varieties near the large complex limit.

Wei-Dong Ruan

In this paper we start the program of constructing generalized special Lagrangian torus fibrations for Calabi-Yau hypersurfaces in toric variety near the large complex limit, with respect to the restriction of a toric metric on the toric variety to the Calabi-Yau hypersurface. The construction is based on the deformation of the standard toric generalized spe

I. Krichever

The discrete Lax operators with the spectral parameter on an algebraic curve are defined. A hierarchy of commuting flows on the space of such operators is constructed. It is shown that these flows are linearized by the spectral transform and can be explicitly solved in terms of the theta-functions of the spectral curves. The Hamiltonian theory of the corresp

P. Wiegmann, A. Zabrodin

We present the first two leading terms of the 1/N (genus) expansion of the free energy for ensembles of normal and complex random matrices. The results are expressed through the support of eigenvalues (assumed to be a connected domain in the complex plane). In particular, the subleading (genus-1) term is given by the regularized determinant of the Laplace op

F. Sannino, M. Shifman

We construct effective Lagrangians of the Veneziano-Yankielowicz (VY) type for two non-supersymmetric theories which are orientifold daughters of supersymmetric gluodynamics (containing one Dirac fermion in the two-index antisymmetric or symmetric representation of the gauge group). Since the parent and daughter theories are planar equivalent, at N\to\infty

M. Czakon

The progress in the evaluation of the muon decay lifetime is reviewed. The electroweak bosonic corrections are given together with the respective shift of the W boson mass. After inclusion of the recently corrected fermionic contributions, this requires an updated fitting formula for the prediction of MW.

Sverker Fredriksson

The Standard Model of quarks and leptons is, at first sight, nothing but a set of {\it ad hoc} rules, with no connections, and no clues to their true background. At a closer look, however, there are many inherent prophecies that point in the same direction: {\it Compositeness} in terms of three stable preons.

S. N. Gninenko, M. M. Kirsanov, N. V. Krasnikov, V. A. Matveev

A possibility to search for a heavy isosinglet (sterile) neutrino using its decay mode $ν_s \to l^{\pm} + 2 jets$ in the $S$ - channel production $pp \to W^* + X \to l^{\pm}ν_s + X$ in the CMS experiment is studied. The only assumption about the heavy neutrino is its nonzero mixing with $ν_e$ or $ν_μ$. The corresponding CMS discovery potential expressed in t

Paul S. Wesson

Heisenberg&#39;s uncertainty relation is commonly regarded as defining a level of unpredictability that is fundamentally incompatible with the deterministic laws embodied in classical field theories such as Einstein&#39;s general relativity. We here show that this is not necessarily the case. Using 5D as an example of dimensionally-extended relativity, we em

Vladimir N. Efremov, Nikolai V. Mitskievich

A quantum model of universe is constructed in which values of dimensionless coupling constants of the fundamental interactions (including the cosmological constant) are determined via certain topological invariants of manifolds forming finite ensembles of 3D Seifert fibrations. The characteristic values of the coupling constants are explicitly calculated as

Oded Regev

We introduce the use of Fourier analysis on lattices as an integral part of a lattice based construction. The tools we develop provide an elegant description of certain Gaussian distributions around lattice points. Our results include two cryptographic constructions which are based on the worst-case hardness of the unique shortest vector problem. The main re

M. Moskalets, M. Buttiker

We investigate a quantum pump which in addition to its dynamic pump parameters is subject to oscillating external potentials applied to the contacts of the sample. Of interest is the rectification of the ac currents flowing through the mesoscopic scatterer and their interplay with the quantum pump effect. We calculate the adiabatic dc current arising under t

Akira Onuki

We present a general theory of electric field effects in liquid crystals where the dielectric tensor depends on the orientation order. As applications, we examine (i) the director fluctuations in nematic states in electric field for arbitrary strength of the dielectric anisotropy and (ii) deformation of the nematic order around a charged particle. Some predi

Emmanuel Tannenbaum, Eric J. Deeds, Eugene I. Shakhnovich

This paper extends Eigen&#39;s quasispecies equations to account for the semiconservative nature of DNA replication. We solve the equations in the limit of infinite sequence length for the simplest case of a static, sharply peaked fitness landscape. We show that the error catastrophe occurs when $ μ$, the product of sequence length and per base pair mismatch

Ji-Yong Park, Sami Rosenblatt, Yuval Yaish, Vera Sazonova

Electron scattering rates in metallic single-walled carbon nanotubes are studied using an atomic force microscope as an electrical probe. From the scaling of the resistance of the same nanotube with length in the low and high bias regimes, the mean free paths for both regimes are inferred. The observed scattering rates are consistent with calculations for ac

V. V. Gafiychuk, A. K. Prykarpatsky

We consider the general properties of the quasispecies dynamical system from the standpoint of its evolution and stability. Vector field analysis as well as spectral properties of such system has been studied. Mathematical modelling of the system under consideration has been performed.

K. Smith, Y. Balega, K. -H. Hofmann, Th. Preibisch

We report H- and K&#39;-band speckle interferometric observations of the HAeBe star V376 Cas. Our observations show that the object is partially resolved. The visibility curves suggest three separate components: a large scattering envelope visible only in the H band, a component approximately 100 mas in radius, and a component with a Gaussian HWHM of approxi

Yousaf Mahmood Butt

I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation.

Donald F. Figer, R. Michael Rich, Sungsoo S. Kim, Mark Morris

We present Hubble Space Telescope (HST) Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations as evidence that continuous star formation has created much of the central stellar cusp of the Galaxy. The data are the deepest ever obtained for a Galactic Center (GC) population, being $>$50% complete for \mnk$<19.3$, or initial stellar masses $\

Francoise Combes

The $Λ$CDM scenario to form galaxies encounters many problems when confronted with observations, namely the prediction of dark matter cusps in all galaxies, and in particular in dwarf irregulars, dominated by dark matter, or the low angular momentum and consequent small size of galaxy disks, or the high predicted number of small systems. We will consider the

D. X. Wang, R. Y. Ma, W. H. Lei, G. Z. Yao

Screw instability of the magnetic field connecting a rotating black hole (BH) with its surrounding disk is discussed based on the model of the coexistence of the Blandford-Znajek (BZ) process and the magnetic coupling (MC) process (CEBZMC). A criterion for the screw instability with the state of CEBZMC is derived based on the calculations of the poloidal and

Lise Christensen, Jens Hjorth, Javier Gorosabel, Paul Vreeswijk

We present a comprehensive study of the z=0.43 host galaxy of GRB 990712, involving ground-based photometry, spectroscopy, and HST imaging. The broad-band UBVRIJHKs photometry is used to determine the global spectral energy distribution (SED) of the host galaxy. Comparison with that of known galaxy types shows that the host is similar to a moderately reddene

Eric G. Blackman

The plethora of asymmetric planetary nebulae and the curiously high momenta of pre-planetary nebula outflows suggest that rotational energy is extracted from the engines. Magneto-rotational outflows driven by dynamos might be operating therein. I summarize scenarios involving (a) an isolated AGB star and (b) a binary. The efficacy of (a) requires re-establis

J. Gorosabel, E. Rol, S. Covino, A. J. Castro-Tirado

We present the results of a VLT polarimetric monitoring campaign of the GRB 020813 optical afterglow carried out in three nights, from 0.88 to 4.20 days after the gamma-ray event. The mean values of the degree of linear polarization (P) and its position angle (Theta) resulting from our campaign are <P>=1.18+/-0.10% and Theta = 148.7+/-2.3 deg after correctin

O. L. G. Peres, A. Yu. Smirnov

We consider oscillations of the low energy (sub-GeV sample) atmospheric neutrinos in the three neutrino context. We present the semi-analytic study of the neutrino evolution and calculate characteristics of the e-like events (total number, energy spectra and zenith angle distributions) in the presence of oscillations. At low energies there are three differen

Damiano Anselmi

I show that under certain conditions it is possible to define consistent irrelevant deformations of interacting conformal field theories. The deformations are finite or have a unique running scale (&#34;quasi-finite&#34;). They are made of an infinite number of lagrangian terms and a finite number of independent parameters that renormalize coherently. The co

Minoru Biyajima, Masaru Ide, Masahiro Kaneyama, Takuya Mizoguchi

To explain η-distributions at RHIC energies we consider the Ornstein-Uhlenbeck process. To account for hadrons produced in the central region, we assume existence of third source located there (y \approx 0) in addition to two sources located at the beam and target rapidities (\pm y_{max} = \pm \ln[\sqrt{s_{NN}}/m_{N}]). This results in better χ^2/n.d.f. than

Damiano Anselmi

In three spacetime dimensions, where no graviton propagates, pure gravity is known to be finite. It is natural to inquire whether finiteness survives the coupling with matter. Standard arguments ensure that there exists a subtraction scheme where no Lorentz-Chern-Simons term is generated by radiative corrections, but are not sufficiently powerful to ensure f

W. Ethan Duckworth

This paper describes how to use subgroups to parameterize unipotent classes in the classical algebraic group in characteristic 2. These results can be viewed as an extension of the Bala-Carter Theorem, and give a convenient way to compare unipotent classes in a group $G$ with unipotent classes of a subgroup $X$ where $G$ is exceptional and $X$ is a Levi subg

Neretin Yu. A

We write spectral decomposition of the hypergeometric differential operator on the contour $Re z=1/2$ (multiplicity of spectrum is 2). As a result, we obtain an integral transform that differs from the Jacobi (or Olevsky) transform. We also try to do a step towards vector-valued special functions and construct a 3F2 orthogonal basis in the space of functions

Y. Kanada-En&#39;yo, Y. Akaishi

We propose new effective inter-nucleon forces with a finite-range three-body operator. The proposed forces are suitable for describing the nuclear structure properties over a wide mass number region, including the saturation point of nuclear matter. The forces are applied to microscopic calculations of $Z=N$ ($A\le 40$) nuclei and O isotopes with a method of

Christophe Deroulers, Rémi Monasson

A quantum field theoretic formulation of the dynamics of the Contact Process on a regular graph of degree z is introduced. A perturbative calculation in powers of 1/z of the effective potential for the density of particles phi(t) and an instantonic field psi(t) emerging from the quantum formalism is performed. Corrections to the mean-field distribution of de

M. de Campos, J. A. Souza

We have obtained analytical exact solutions of the Dyer-Roeder equation in a cosmological model where creation of particles occurs at the expenses of the gravitational field. We discussed the influences of inhomogeneities in the path of a light beam on the apparent diameter of astrophysical objects and consider both redshift independent as redshift dependent

Jian-gang Hao, Xin-zhou Li

We study the dynamics of phantom model and give the conditions for potentials to admit tracking attractor, de Sitter attractor and big rip attractor. Especially, we show that phantom models with exponential and inverse power law potentials do not admit the tracking attractor solution. The &#34;tachyonic&#34; stability of the system at/near the attractors as

I-Ching Yang, Irina Radinschi

The energy distributions of four 2+1 dimensional black hole solutions were obtained by using the Einstein and Møller energy-momentum complexes. while $r \to \infty$, the energy distributions of these four solutions become divergence.

Masako Bando, Satoru Kaneko, Midori Obara, Morimitu Tanimoto

We study the symmetric texture of geometric form with 2-zeros to see if it is consistent with the presently-known neutrino masses and mixings. In the neutrino mass matrix elements we obtain numerically the allowed region of the parameters including CP violating phases, which can reproduce the present neutrino experiment data. The result of this analysis dict

Eric Pfahl, Avi Loeb

The supermassive black hole at the Galactic center harbors a bound cluster of massive stars that should leave neutron-star remnants. Extrapolating from the available data, we estimate that 100-1000 radio pulsars may presently orbit Sgr A* with periods of <~100 yr. Optimistically, 1-10 of the most luminous of these pulsars may be detectable with current teles

Li-zhen Jiang

I study the three parameters bipartite quantum Gaussian state called squeezed asymmetric thermal state, calculate Gaussian entanglement of formation analytically and the up bound of relative entropy of entanglement, compare them with coherent information of the state.Based on the result obtained, one can determine the relative entropy of entanglement of the

Robert C. Hilborn, Rebecca J. Erwin

We demonstrate the existence of noise-induced periodicity (coherence resonance) in both a discrete-time model and a continuous-time model of an excitable neuron. In particular, we show that the effects of noise added to the fast and slow dynamics of the models are dramatically different. A Fokker-Planck analysis gives a quantitative explanation of the effect