October 2003 arXiv papers — page 8

L. V. Bogdanov, B. G. Konopelchenko

It is proved that the action for nonlinear Beltrami equation (quasiclassical dbar-problem) evaluated on its solution gives a tau-function for dispersionless KP hierarchy. Infinitesimal transformations of tau-function corresponding to variations of dbar-data are found. Determinant equations for the function generating these transformations are derived. They r

Tom Kennedy

We consider the highly anisotropic ferromagnetic spin 1/2 Heisenberg chain with periodic boundary conditions. In each sector of constant total z component of the spin, we develop convergent expansions for the lowest band of eigenvalues and eigenfunctions. These eigenstates describe droplet states in which the spins essentially form a single linear droplet wh

Gert H. M. van der Heijden, Mark A. Peletier, Robert Planqué

We combine and extend the work of Alexander & Antman \cite{alexander.82} and Fuller \cite{fuller.71,fuller.78} to give a framework within which precise definitions can be given of topological and geometrical quantities characterising the contortion of open rods undergoing large deformations under end loading. We use these definitions to examine the extension

Shigeki Matsutani

This article is devoted to an investigation of a reality condition of a hyperelliptic loop soliton of higher genus. In the investigation, we have a natural extension of Jacobi am-function for an elliptic curves to that for a hyperelliptic curve. We also compute winding numbers of loop solitons.

Victor I. Lahno, Olena V. Magda

The problem of group classification of one class of quasilinear equations of hyperbolic type with two independent variables has been solved completely.

Kai-Uwe Bux

We describe a series of complexes that relate to the braid groups as the matching complexes relate to the symmetric groups. A modified construction applies as well to other complexes based on edge sets in graphs. We show that our constructions will yield Cohen-Macauley complexes provided the underlying complexes are Cohen-Macauley. Finally, we discuss a rela

S. Tanabe, M. N. Vrahatis

A problem concerning the shift of roots of a system of homogeneous algebraic equations is investigated. Its conservation and decomposition of a multiple root into simple roots are discussed.

Jason Tyler

We show how to modify any Bratteli diagram $E$ for an AF-algebra $A$ to obtain a Bratteli diagram $KE$ for $A$ whose graph algebra $C^*(KE)$ contains both $A$ and $C^*(E)$ as full corners.

Turker Ozsari

I give some claims on primorial prime numbers for interested readers in number theory.

Cedric lecouvey

We establish a Morris type recurrence formula for the root system $C_{n}$.\ Next we introduce cyclage graphs for the corresponding Kashiwara-Nakashima's tableaux and use them to define a charge statistic. Finally we conjecture that this charge may be used to compute the Kostka-Foulkes polynomials for type $C_{n}.$

B. Khesin, A. Rosly, R. P. Thomas

We prove an analogue of the de Rham theorem for polar homology; that the polar homology $HP_q(X)$ of a smooth projective variety $X$ is isomorphic to its $H^{n,n-q}$ Dolbeault cohomology group. This analogue can be regarded as a geometric complexification where arbitrary (sub)manifolds are replaced by complex (sub)manifolds and de Rham's operator $d$ is

Kazuhiro Ichihara

The infimal Heegaard gradient of a compact 3-manifold was defined and studied by Marc Lackenby in an approach toward the well-known virtually Haken conjecture. As instructive examples, we consider Seifert fibered 3-manifolds, and show that a Seifert fibered 3-manifold has zero infimal Heegaard gradient if and only if it virtually fibers over the circle or ov

Caterina Consani, Matilde Marcolli

In this survey, written for the proceedings of the VII meeting of the CNTA held in May 2002 in Montreal, we describe how Connes' theory of spectral triples provides a unified view, via noncommutative geometry, of the archimedean and the totally split degenerate fibers of an arithmetic surface.

Caterina Consani, Matilde Marcolli

In Arakelov theory a completion of an arithmetic surface is achieved by enlarging the group of divisors by formal linear combinations of the ``closed fibers at infinity''. Manin described the dual graph of any such closed fiber in terms of an infinite tangle of bounded geodesics in a hyperbolic handlebody endowed with a Schottky uniformization. In th

Raman Sundrum

The cosmological constant problem is usually considered an inevitable feature of any effective theory capturing well-tested gravitational and matter physics, without regard to the details of short-distance gravitational couplings. In this paper, a subtle effective description avoiding the problem is presented in a first quantized language, consistent with ex

D. Baleanu, Y. Guler

The equivalence of the chain method and Hamilton-Jacobi formalism is demonstrated. The stabilization algorithm of Hamilton-Jacobi formalism is clariffied and two examples are presented in details.

Vishesh Khemani

We explore the space of solutions of the classical equations of motion in the Euclidean electroweak theory. We sketch a topological prescription that finds known solutions and indicates the existence of novel ones. All spatially-varying, time-independent solutions are unstable. However, if we consider quantum fluctuations around static classical configuratio

Stanislaw D. Glazek

The similarity renormalization group procedure formulated in terms of effective particles is briefly reviewed in a series of selected examples that range from the model matrix estimates of its numerical accuracy to issues of the Poincare symmetry in constituent theories to derivation of the Schroedinger equation for quarkonia in QCD.

Ashok Das

In this talk, we describe our present understanding of thermal field theories on the light-front with an application to Schwinger model.

Florian Conrady, Carlo Rovelli

We investigate the idea of a "general boundary" formulation of quantum field theory in the context of the Euclidean free scalar field. We propose a precise definition for an evolution kernel that propagates the field through arbitrary spacetime regions. We show that this kernel satisfies an evolution equation which governs its dependence on deformati

C. Bizdadea, C. C. Ciobirca, E. M. Cioroianu, S. O. Saliu

The local and manifestly covariant Lagrangian interactions in four spacetime dimensions that can be added to a ``free'' model that describes a generic matter theory and an abelian BF theory are constructed by means of deforming the solution to the master equation on behalf of specific cohomological techniques.

Junji Kato, Noboru Kawamoto, Yukiya Uchida

We propose a twisted D=N=2 superspace formalism. The relation between the twisted super charges including the BRST charge, vector and pseudo scalar super charges and the N=2 spinor super charges is established. We claim that this relation is essentially related with the Dirac-Kähler fermion mechanism. We show that a fermionic bilinear form of twisted N=2 chi

Ilja Schmelzer

Based on the geometric interpretation of the Dirac equation as an evolution equation on the three-dimensional exterior bundle /(R^3), we propose the bundle (T x / x /)(R^3) as a geometric interpretation of all standard model fermions. The generalization to curved background requires an ADM decomposition M^4=M^3 x R and gives the bundle (T x / x /)(M^3). As a

Soon-Tae Hong

This paper was withdrawn by the author.

J. Teschner

The aim of this note is to propose an interpretation for the full (non-chiral) correlation functions of the Liouville conformal field theory within the context of the quantization of spaces of Riemann surfaces.

Thomas DeGrand

Euclidean space hadronic correlators are computed in quenched QCD at small quark mass using truncations of quark propagators which include or exclude low eigenvalue eigenmodes of the Dirac operator. High modes provide the dominant contribution to parity averaged correlators, especially at short distances. Differences of correlators of opposite parity receive

H. Wittig, A. A. Petrov, D. G. Cassel

We introduce the contributions to the proceedings of Working Group V. The main topics were: present and future experiments dedicated to charm physics, the interplay between high-precision measurements and better control over theoretical uncertainties, and searches for signals of new physics in the charm sector. The comparison of Lattice QCD calculations with

A. H. Hoang

I give an introduction to the effective field theory description of top pair production at threshold in e+e- annihilation. The impact of the summation of logarithms of the top quark velocity including most recent results at next-to-next-to-leading logarithmic order is discussed.

Sabine Jeschonnek, J. W. Van Orden

We discuss a model for the study of quark-hadron duality in inclusive electron scattering based on solving the Dirac equation numerically for a scalar confining linear potential and a vector color Coulomb potential. We qualitatively reproduce the features of quark-hadron duality for all potentials considered, and discuss similarities and differences to previ

Tetsuo Nishikawa, Yoshimasa Hidaka, Munehisa Ohtani, Osamu Morimatsu

We study the effect of the thermal width of $π$ on the spectral function of $σ$. In order to take into account a finite thermal width of $π$, we replace the internal pion mass in the self-energy of $σ$ with that of the complex pole found in a previous paper. The obtained spectral function for $T\aplg 100 {\rm MeV}$ turns out to possess two broad peaks. Altho

P. Petreczky

I discuss quarkonium spectral functions at finite temperature reconstructed using the Maximum Entropy Method. I show in particular that the J/psi survives in the deconfined phase up to 1.5Tc

Taku Izubuchi

We report preliminary results from an ongoing calculation of $B_K$ for $N_f=2$ dynamical QCD with domain wall fermions. Simulations have been done with three dynamical quark masses on $16^3 \times 32$ volumes with $L_s = 12$, where the lattice spacing is $a^{-1} = 1.81(6)$ GeV. Using measurements on $\sim 70$ lattices for each dynamical mass and extrapolatin

The OPAL collaboration, G. Abbiendi

A search for pair-produced scalar fermions under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about 610 pb-1 collected at centre-of-mass energies of sqrt(s) 189-209 GeV. An important consequence of R-parity violation is

P. Krokovny

New results on hadron physics from the Belle experiment are presented

Stephen F. Pate

A new method of obtaining the strange form factors of the nucleon is presented, in which forward-angle parity-violating $\vec{e}p$ elastic scattering data is combined with $νp$ and $\barν p$ elastic scattering data. The axial form factor in electron-nucleon scattering is complicated by the presence of electro-weak radiative corrections that in principle need

R. Jackiw

When 4-dimensional general relativity is extended by a 3-dimensional gravitational Chern-Simons term an apparent violation of diffeormorphism invariance is extinguished by the dynamical equations of motion for the modified theory. The physical predictions of this recently proposed model show little evidence of symmetry breaking, but require the vanishing of

V. D. Ivashchuk

This short review deals with a multidimensional gravitational model containing dilatonic scalar fields and antisymmetric forms. The manifold is chosen in the product form. The sigma-model approach and exact solutions are reviewed.

Leszek M. Sokolowski

It is postulated in general relativity that the matter energy-momentum tensor (named the stress tensor) vanishes if and only if all the matter fields vanish. In classical lagrangian field theory the stres tensor is the variational (symmetric) one and a priori it might occur that for some systems the tensor is identically zero for all field configurations whe

K. A. Bronnikov, V. N. Melnikov

We review some results concerning the properties of static, spherically symmetric solutions of multidimensional theories of gravity: various scalar-tensor theories and a generalized string-motivated model with multiple scalar fields and fields of antisymmetric forms associated with p-branes. A Kaluza-Klein type framework is used: there is no dependence on in

Michael Mattes

The Einsteinian Theory of Gravitation ("General Theory of Relativity") is founded essentially; on the reception that the geometrical properties of the 4-dimensional space-time continuum are defined from the matter in it. Contrary to this, in the Newtonian Mechanics space and time obey a absolute, matter-independent meaning. This thesis offers a compr

Turker Ozsari

In this paper, we present a general review of hash functions in a cryptographic sense. We give special emphasis on some particular topics such as cipher block chaining message authentication code (CBC MAC) and its variants. This paper also broadens the information given in some well known surveys, by including more details on block-cipher based hash function

Farn Wang

We use dense variable-ordering to define HRD (Hybrid-Restriction Diagram), a new BDD-like data-structure for the representation and manipulation of state-spaces of linear hybrid automata. We present and discuss various manipulation algorithms for HRD, including the basic set-oriented operations, weakest precondition calculation, and normalization. We impleme

M. W. Haverkort, S. I. Csiszar, Z. Hu, S. Altieri

We have detected strong dichroism in the Ni $L_{2,3}$ x-ray absorption spectra of monolayer NiO films. The dichroic signal appears to be very similar to the magnetic linear dichroism observed for thicker antiferromagnetic NiO films. A detailed experimental and theoretical analysis reveals, however, that the dichroism is caused by crystal field effects in the

C. Danilowicz, Y. Kafri, R. S. Conroy, V. W. Coljee

We separate double stranded lambda phage DNA by applying a fixed force at a constant temperature ranging from 15C to 50C, and measure the minimum force required to separate the two strands, providing the first experimental determination of the phase boundary between single stranded DNA and double stranded DNA in the temperature- force plane. The measurements

A. T. Boothroyd, P. G. Freeman, D. Prabhakaran, A. Hiess

We have observed a diffuse component to the low-energy magnetic excitation spectrum of stripe-ordered La5/3Sr1/3NiO4 probed by neutron inelastic scattering. The diffuse scattering forms a square pattern with sides parallel and perpendicular to the stripe directions. The signal is dispersive, with a maximum energy of ~10 meV. Probed at 2 meV the scattering de

I. I. Mazin, D. J. Singh

The magnetic properties of the weak itinerant ferromagnet ZrZn_2 are analyzed using Landau theory based on a comparison of density functional calculations and experimental data as a function of field and pressure. We find that the magnetic properties are strongly affected by the nearby quantum critical point, even at zero pressure; LDA calculations neglectin

A. Ghosh, C. J. B. Ford, M. Pepper, H. E. Beere

We have experimentally studied the non-equilibrium transport in low-density clean 2D electron systems at mesoscopic length scales. At zero magnetic field (B), a double-peak structure in the non-linear conductance was observed close to the Fermi energy in the localized regime. From the behavior of these peaks at non-zero B, we could associate them to the oppo

J. L. Smith, J. C. Lashley

Hysteresis has been observed in de Haas-van Alphen measurements of the Condon domains in silver, and it shows the first-order nature of the transition to the domain state. The hysteresis, and thus the first-order nature, is manifested in a nonlinear effect where a double-valued response of the amplitude with the applied external field is observed.

R. Crook, C. G. Smith, A. C. Graham, I. Farrer

We present scanning-probe images and magnetic-field plots which reveal fractal conductance fluctuations in a quantum billiard. The quantum billiard is drawn and tuned using erasable electrostatic lithography, where the scanning probe draws patterns of surface charge in the same environment used for measurements. A periodicity in magnetic field, which is obse

L. H. Yu, D. Natelson

We have used an electromigration technique to fabricate C$_{60}$-based single-molecule transistors. We detail the process statistics and the protocols used to infer the successful formation of a single-molecule transistor. At low temperatures each transistor acts as a single-electron device in the Coulomb blockade regime. Resonances in the differential condu

S. Sugahara, M. Tanaka

We propose and theoretically analyze a novel metal-oxide-semiconductor field-effect-transistor (MOSFET) type of spin transistor (hereafter referred to as a spin MOSFET) consisting of a MOS gate structure and half-metallic-ferromagnet (HMF) contacts for the source and drain. When the magnetization configuration between the HMF source and drain is parallel (an

Munehisa Matsumoto, Synge Todo, Chitoshi Yasuda, Hajime Takayama

We study the ground-state phase transitions of quasi-one-dimensional quantum Heisenberg antiferromagnets by the quantum Monte Carlo method with the continuous-time loop algorithm and finite-size scaling. For a model which consists of S=1 chains with bond alternation coupled on a square lattice, we determine the ground state phase diagram and the universality

Robert Dahlke, Ulrich Schollwoeck

We report on electronic transport calculations for self-assembled mono-layers (SAM) of 1,4-phenylene diisocyanide on Au(111) contacts. Experimentally one observes more structure (i.e peaks) within the measured conductance curve for this molecule with two cyanide end-groups, compared to measurements with molecules having thiol end-groups. The calculations are

Akinori Tanaka

We present a class of exactly solvable models of correlated electrons. The models are defined in any dimension $d$ and consist of electron-hopping terms and local attractive interactions between electrons. For each even number of electrons less than or equal to $1/(d+1)$-filling, we find the exact ground state in which all electrons form pairs of a certain t

Y. Aiura, I. Hase, H. Bando, K. Yagi-Watanabe

We present an angle-resolved photoemission (ARPES) study on the layered transition-metal dichalcogenide 1{\em T}-TaS$_{1.2}$Se$_{0.8}$ in the metallic commensurate charge-density-wave (CDW) phase. A model calculation of the spectral function captures the main features of the ARPES spectra well qualitatively, that is, the gross splits of unreconstructed band

B. Spagnolo, A. Fiasconaro, D. Valenti

We study the time evolution of two ecosystems in the presence of external noise and climatic periodical forcing by a generalized Lotka-Volterra (LV) model. In the first ecosystem, composed by two competing species, we find noise induced phenomena such as: (i) quasi deterministic oscillations, (ii) stochastic resonance, (iii) noise delayed extinction and (iv)

Akilan Palanisami, M. B. Weissman, N. D Mathur

The paper was withdrawn by the authors, due to an error in interpretation by Weissman. There is a first-order jump, but it's intrinsically a non-equilibrium thermal instability effect.

H. W. Diehl, A. Gerwinski, S. Rutkevich

The critical behavior of semi-infinite $d$-dimensional systems with $n$-component order parameter $\bmϕ$ and short-range interactions is investigated at an $m$-axial bulk Lifshitz point whose wave-vector instability is isotropic in an $m$-dimensional subspace of $\mathbb{R}^d$. The associated $m$ modulation axes are presumed to be parallel to the surface, wh

Xia-Ji Liu, Michele Modugno, Hui Hu

By using the self-consistent Hartree-Fock-Bogoliubov-Popov theory, we present a detailed study of the mean-field stability of spherically trapped Bose-Fermi mixtures at finite temperature. We find that, by increasing the temperature, the critical particle number of bosons (or fermions) and the critical attractive Bose-Fermi scattering length increase, leadin

H. W. Diehl, M. A. Shpot, R. K. P. Zia

The critical behavior of $d$-dimensional systems with $n$-component order parameter $\bmϕ$ is studied at an $m$-axial Lifshitz point where a wave-vector instability occurs in an $m$-dimensional subspace ${\mathbb R}^m$ ($m{>}1$). Field theoretic renormalization group techniques are exploited to examine the effects of terms in the Hamiltonian that break the r

M. M. Fogler, S. Teber, B. I. Shklovskii

We study the effect of impurities on the ground state and the low-temperature dc transport in a 1D chain and quasi-1D systems of many parallel chains. We assume that strong interactions impose a short-range periodicicity of the electron positions. The long-range order of such an electron crystal (or equivalently, a $4 k_F$ charge-density wave) is destroyed b

Claes Andersson, Alexander Hellervik, Kristian Lindgren

The presented model provides an explanation to several empirically observed phenomena in spatial economics. By representing the system as a complex network of fixed-size land areas connected by trade between harbored activities, city size and land value distributions are obtained as higher-order patterns. The model predicts the empirically observed spatial d

Meret Kraemer, Chiara Menotti, Lev Pitaevskii, Sandro Stringari

We discuss the Bloch-state solutions of the stationary Gross-Pitaevskii equation and of the Bogoliubov equations for a Bose-Einstein condensate in the presence of a one-dimensional optical lattice. The results for the compressibility, effective mass and velocity of sound are analysed as a function of the lattice depth and of the strength of the two-body inte

A. B. McDonald

The current knowledge of neutrino properties has been derived from measurements performed with both astrophysical and terrestrial sources. Observations of neutrino flavor change have been made with neutrinos generated in the solar core, through cosmic ray interactions in the atmosphere and in nuclear reactors. A summary is presented of the current knowledge

D. S. Shepherd, D. E. A. Nurnberger, L. Bronfman

We have observed the massive star forming region, IRAS 18507+0121, at millimeter wavelengths in 3 mm continuum emission and H13CO+(J=1-0) and SiO(v=0, J=2-1) line emission, and at near-infrared wavelengths between 1.2 and 2.1 microns. Two compact molecular cores are detected: one north and one south separated by about 40". The northern molecular core con

S. -C. Rey, Y. -W. Lee, C. Ree, J. -M. Joo

We present wide-field and high-precision BV and Ca & Stromgren by photometry of omega Centauri, which represents one of the most extensive photometric surveys to date for this cluster. The member stars of omega Cen are well discriminated from foreground Galactic field stars in the hk [=(Ca-b)-(b-y)] vs. b-y diagram. The resulting "cleaned" color-magn

P. Gandhi, C. S. Crawford, A. C. Fabian, R. M. Johnstone

We present a small sample of Chandra X-ray sources selected from the fields of ACIS observations which probe fluxes around the break in the hard band source counts. The targets of these fields include 9 nearby galaxy clusters, 1 distant cluster and 2 powerful radio galaxy fields. The follow-up of this serendipitous sample was biased towards X-ray hard and op

Lucio Mayer, Thomas Quinn, James Wadsley, Joachim Stadel

We carry out a large set of very high resolution, three dimensional smoothed particle hydrodynamics (SPH) simulations describing the evolution of gravitationally unstable gaseous protoplanetary disks. We consider a broad range of initial disk parameters. Disk masses out to 20 AU range from 0.075 to 0.125 $M_{\odot}$, roughly consistent with the high-end of t

Kentaro Nagamine, Volker Springel, Lars Hernquist

We study the distribution of star formation rate (SFR) and metallicity of damped Lyman-alpha absorbers (DLAs) using cosmological smoothed particle hydrodynamics (SPH) simulations of the Lambda cold dark matter model. Our simulations include a phenomenological model for feedback by galactic winds which allows us to examine the effect of galactic outflows on t

Andrew J. Fox, Blair D. Savage, Bart P. Wakker, Philipp Richter

We present Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope observations of high, intermediate, and low ion absorption in high-velocity cloud Complex C along the lines of sight toward five active galaxies. Our purpose is to investigate the idea that Complex C is surrounded by an envelope of highly ionized material, arising from the interacti

Dan Maoz, Avishay Gal-Yam

The iron mass in galaxy clusters is about 6 times larger than could have been produced by core-collapse SNe, assuming the stars in cluster galaxies formed with a standard IMF. Type-Ia SNe have been proposed as the alternative dominant iron source. We use our HST measurements of the cluster SN-Ia rate at high redshift to study the cluster iron enrichment scen

Oleg Kargaltsev, George Pavlov

A series of 13 Chandra observations provided the deepest images of the Vela PWN yet available. In addition to the fine structure of the inner PWN features, a much larger and fainter asymmetric X-ray nebula emerges in the summed images. The shape of this outer PWN is similar to that of the radio PWN. We also present the spectral map of the Vela PWN that revea

Antonio Aparicio

The Local Group provides an interesting and representative sample of galaxies in the rest of the Universe. The high accuracy with which many problems can be addressed in Local Group galaxies is of paramount importance for understanding galaxy formation and evolution. This contribution presents a short review of overall Local Group properties followed by shor

Jayaram N. Chengalur, Nissim Kanekar

We describe a new technique to estimate variations in the fundamental constants using 18cm OH absorption lines. This has the advantage that all lines arise in the same species, allowing a clean comparison between the measured redshifts. In conjunction with one additional transition (for example, an HCO$^+$ line), it is possible to simultaneously measure chan

W. R. Hix, A. Mezzacappa, O. E. B. Messer, S. W. Bruenn

New facilities to measure neutrino-nucleus cross sections, such as those possible in conjunction with spallation neutron sources, could provide an experimental foundation for the many neutrino-nucleus weak interaction rates needed in supernova models. This would enable more realistic supernova models and provide a greatly improved ability to understand the p

Felix J. Lockman, Jeroen M. Stil

The VLA Galactic Plane Survey (VGPS) consists of measurements of the 21cm HI line and 1420 MHz continuum at 1' angular resolution over much of the first quadrant of Galactic longitude within a few degrees of the Galactic plane. In combination with similar surveys of the fourth longitude quadrant and the outer Galaxy made with other instruments, the VGPS

N. Kanekar, J. N. Chengalur, A. G. de Bruyn, D. Narasimha

We present deep GMRT OH and WSRT HI absorption spectra of the $z = 0.6846$ gravitational lens toward B0218+357. Both the 1665 MHz and 1667 MHz OH lines are clearly detected for the first time while a new wide absorption component was detected (at low significance) in the HI spectrum; the OH spectra yielded an OH column density of $N_{OH} = 2.3 \times 10^{15}

R. P. Woodard

The expansion of spacetime alters the energy-time uncertainty principle, allowing virtual particles to persist longer than in flat space. For a given expansion the effect is largest for massless particles which are not conformally invariant. For a given particle type the effect is largest for inflation. I exhibit these two principles in the context of massle

Henk Hoekstra, Howard K. C. Yee, Michael D. Gladders

We present the results of a study of the average mass profile around galaxies using weak gravitational lensing. We use 45.5 deg^2 of R_C band imaging data from the Red-Sequence Cluster Survey (RCS) and define a sample of 1.2\times 10^5 lenses with 19.5<R_C<21, and a sample of 1.5\times 10^6 background galaxies with 21.5<R<24. We constrain the power law scali

Stephane Bargot

I will briefly present my work on cosmological parameters estimation. Classical methods for parameters estimation involve the exploration of the parameter space on a precalculated grid of cosmological models. Here we try to estimate the cosmological parameters by using a minimization method associated with the interpolation of the C_l spectrum. We first use

G. Fiorentini, B. Ricci

In this brief review we discuss the possibility of studying the solar interior by means of neutrinos, in the light of the enormous progress of neutrino physics in the last few years. The temperature near the solar center can be extracted from Boron neutrino experiments as: $ T= (1.57 \pm 0.01) 10^7 K$. The energy production rate in the Sun from pp chain and

L. Wyrzykowski, A. Udalski, P. L. Schechter, O. Szewczyk

We present results of the long term monitoring of the gravitationally lensed quasar HE1104-1805. The photometric data were collected between August 1997 and January 2002 as a subproject of the OGLE survey. We determine the time delay in the light curves of images A and B of HE1104-1805 to be equal to 157+/-21 days with the variability in the image B light cu

Jiri Krticka, Jiri Kubat

We calculate multicomponent stellar wind models with inclusion of a helium component applicable to He-rich and He-poor stars. We show that helium does not decouple from the stellar wind of He-rich stars due to its coupling to hydrogen and its ionized state. For He-poor stars helium may decouple from the stellar wind, however this effect is not able to explai

G. I. Gomero

It is shown here how prior estimates on the local shape of the universe can be used to reduce, to a small region, the full parameter space for the search of circles in the sky. This is the first step towards the development of efficient estrategies to look for these matched circles in order to detect a possible nontrivial topology of our Universe. It is show

M. A. McLaughlin, J. M. Cordes

Using a likelihood analysis (updated since McLaughlin & Cordes 2000) and EGRET detections, upper limits and diffuse background measurements, we find a best-fit luminosity law for the gamma-ray pulsar population. We find that roughly 30 of the 170 unidentified EGRET sources are likely to be pulsars. This is roughly twice the number of known radio pulsars whic

Nektarios Vlahakis, Arieh Konigl

There is growing evidence that relativistic jets in active galactic nuclei undergo extended (parsec-scale) acceleration. We argue that, contrary to some suggestions in the literature, this acceleration cannot be purely hydrodynamic. Using exact semianalytic solutions of the relativistic MHD equations, we demonstrate that the parsec-scale acceleration to rela

V. D&#39;Elia, F. Fiore, M. Elvis, M. Cappi

We present a statistical analysis of the Chandra observation of the source field around the 3C 295 galaxy cluster ($z=0.46$). The logN-logS of this field is in good agreement with that computed for the Chandra Deep Field South in this work and in previous ones. Nevertheless, the logN-logS computed separately for the four ACIS-I chips reveals that there is a

S. Pfalzner

A prerequisite for the formation of stars and planetary systems is that angular momentum is transported in some way from the inner regions of the accretion disc. Tidal effects may play an important part in this angular momentum transport. Here the angular momentum transfer in an star-disc encounter is investigated numerically for a variety of encounter param

A. Cimatti, E. Daddi, P. Cassata, E. Pignatelli

Deep VLT optical spectroscopy, HST+ACS (GOODS) imaging and VLA observations are used to unveil the nature of a complete sample of 47 EROs with R-Ks>5 and Ks<20. The spectroscopic redshift completeness is 62%. Morphological classification was derived for each ERO through visual inspection and surface brightness profile fitting. Three main ERO morphological ty

T. Bensby, S. Feltzing, I. Lundstrom

We present oxygen abundances for 72 F and G dwarf stars in the solar neighbourhood. Using the kinematics of the stars we divide them into two sub-samples with space velocities that are typical for the thick and thin disks, respectively. The metallicities of the stars range from [Fe/H] = -0.9 to +0.4 and we use the derived oxygen abundances of the stars to: (

J. Scharwaechter, A. Eckart, S. Pfalzner, J. Zuther

The first successful multi-particle model for the host of the well-known quasi-stellar object (QSO) 3C 48 is reported. It shows that the morphology and the stellar velocity field of the 3C 48 host can be reproduced by the merger of two disk galaxies. The conditions of the interaction are similar to those used for interpreting the appearance of the &#39;&#39;

Jonathan C. Tan

I compare theoretical models of massive star formation with observations of the Orion Hot Core, which harbors one of the closest massive protostars. Although this region is complicated, many of its features (size, luminosity, accretion disk, HII region, outflow) may be understood by starting with a simple model in which the star forms from a massive gas core

Paul Seidel

This proves Kontsevich&#39;s mirror conjecture for (on the symplectic side) a quartic surface in P^3.

Hans-Christian Pauli

The long standing problem of non perturbative renormalization of a gauge field theoretical Hamiltonian is addressed and explicitly carried out within an (effective) light-cone Hamiltonian approach to QCD. The procedure is in line with the conventional ideas: The Hamiltonian is first regulated by suitable cut-off functions, and subsequently renormalized by su

Dirk Rannacher, Andreas Engel

We consider a horizontal ferrofluid layer sandwiched between two layers of immiscible non-magnetic fluids. In a sufficiently strong vertical magnetic field the flat interfaces between magnetic and non-magnetic fluids become unstable to the formation of peaks. We theoretically investigate the interplay between these two instabilities for different combination

H. Q. Zheng, Z. Y. Zhou, G. Y. Qin, Z. G. Xiao

A new unitarization approach incorporated with chiral symmetry is established and applied to study the $πK$ elastic scatterings. We demonstrate that the $κ$ resonance exists, if the scattering length parameter in the I=1/2, J=0 channel does not deviate much from its value predicted by chiral perturbation theory. The mass and width of the $κ$ resonance is fou

Aurel Bulgac, Yongle Yu

We present a concise account of our development of the first genuine Local Density Approximation (LDA) to the Energy Density Functional (EDF) for fermionic systems with superfluid correlations, with a particular emphasis to nuclear systems.

Peter Cho, Karl Berggren

A numerical method for solving Schrodinger&#39;s equation based upon a Baker-Campbell-Hausdorff (BCH) expansion of the time evolution operator is presented herein. The technique manifestly preserves wavefunction norm, and it can be applied to problems in any number of spatial dimensions. We also identify a particular dimensionless ratio of potential to kinet

Dagomir Kaszlikowski, Lim Jenn Yang, L. C. Kwek, Berthold-Georg Englert

We report that, for the generation of a secure cryptographic key from correlations established through a noisy quantum channel, the quantum and classical advantage distillation procedures are not equivalent, when coherent eavesdropping attacks are duly taken into account. The quantum procedure can tolerate markedly more noise in the channel than the classica

Barry C. Sanders, Stephen D. Bartlett, Terry Rudolph, Peter L. Knight

We introduce the entangled coherent state representation, which provides a powerful technique for efficiently and elegantly describing and analyzing quantum optics sources and detectors while respecting the photon number superselection rule that is satisfied by all known quantum optics experiments. We apply the entangled coherent state representation to eluc