October 2000 arXiv papers — page 8

Bastian Kubis, Ulf-G. Meißner

We analyze the electromagnetic form factors of the ground state baryon octet to fourth order in relativistic baryon chiral perturbation theory. Predictions for the Σ^- charge radius and the Λ-Σ^0 transition moment are found to be in excellent agreement with the available experimental information. Furthermore, the convergence behavior of the hyperon charge ra

Jörg Hüfner, Boris Z. Kopeliovich, Alberto Polleri

In high energy nuclear collisions, the conventional Glauber model is commonly used to evaluate the contribution to $J/ψ$ suppression originating from the inelastic interaction with colorless bound nucleons. This requires an effective value for the $J/ψ$-nucleon absorption cross section which is larger than theoretically expected. On the other hand, multiple

Jiao Lin Xu

This paper has deduced the baryon spectrum using only 2 flavored quarks u and d (each of them has three colored members). From Dirac's sea concept and the quark confinement idea, we conjecture and then assume that the quarks (in the vacuum state) compose colorless particles (uud and udd, hereafter will be called the Lee Particles). Moreover, the Lee Part

V. A. Saleev

The two-particle hadronic decays of B_c meson into S-wave and P-wave charmonium states X_cc are considered in the framework of hard gluon exchange model. It is shown that decay width of B_c meson into S-wave charmonium states doubly exceeds one for S-wave states. In compare with the previous estimations we predict the enhancement by 8 % the branching ratio f

S. Cheluvaraja

We investigate some properties of thick vortices and thick monopoles in the SU(2) lattice gauge theory by inserting operators that create these excitations. We measure the derivative of the free energy of the vortex with respect to the coupling and we find that it falls exponentially with the cross sectional area of the vortex. We also study the monopole-mon

M. Campostrini, M. Hasenbusch, A. Pelissetto, P. Rossi

Three-dimensional spin models of the Ising and XY universality classes are studied by a combination of high-temperature expansions and Monte Carlo simulations. Critical exponents are determined to very high precision. Scaling amplitude ratios are computed via the critical equation of state. Our results are compared with other theoretical computations and wit

F. Karsch, E. Laermann, A. Peikert, Ch. Schmidt

We calculate the transition temperature in 2 and 3-flavor QCD using improved gauge and staggered fermion actions on lattices with temporal extent Nt=4. We find Tc=173(8)MeV and 154(8)MeV for nf=2 and 3, respectively. In the case of 3-flavor QCD we present evidence that the chiral critical point, i.e. the second order endpoint of the line of first order chira

H. Fischer, J. Franz, A. Grunemaier, F. H. Heinsius

In the scope of the COMPASS experiment a multi-purpose, high rate capable TDC with digitisation width of 60 ps has been developed. The integration into the readout system and the flexible input of the CATCH readout driver is presented.

Richard Haas

We report the results of a search for second and third generation leptoquarks using 88 ${pb}^{-1}$ of data recorded by the Collider Detector at Fermilab. Color triplet technipions, which play the role of scalar leptoquarks, are investigated due to their potential production in decays of strongly coupled color octet technirhos. Events with a signature of two

Richard Haas

Events with signatures involving large missing transverse energy (MET) are among the quintessential search modes for R-parity conserving supersymmetry. CDF has conducted two recent analyses for supersymmetry which use MET and jets. The MET and monojet signature is employed to determine process independent limits for the production of new physics beyond the S

ALEPH Collaboration

Searches for neutral Higgs bosons are performed with the 237 pb-1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of the Standard Model and its minimal supersymmetric extension (MSSM) as well as to invisibly decaying Higgs bosons. No evide

Irina Radinschi

We obtain the energy of a conformal scalar dyon black hole (CSD) by using the energy-momentum complexes of Tolman and Møller. The total gravitational energy is given by the CSD charge in the both prescriptions.

Irina Radinschi

We obtain the energy distribution of a Schwarzschild black hole in a magnetic universe in the Tolman prescription.

M. V. Feigel'man, A. I. Larkin, M. A. Skvortsov

A theory of the zero-temperature superconductor-metal transition is developed for an array of superconductive islands (of size d) coupled via a disordered two-dimensional conductor with the dimensionless conductance g>>1. At T=0 macroscopically superconductive state of the array with the lattice spacing b>>d is destroyed at g < g_c \approx 0.1 ln^2(b/d). At

K. Varga, P. Navratil, J. Usukura, Y. Suzuki

The spectra of quantum dots of different geometry (``quantum ring&#39;&#39;, ``quantum cylinder&#39;&#39;, ``spherical square-well&#39;&#39; and ``parabolic confinement&#39;&#39;) are studied. The stochastic variational method on correlated Gaussian basis functions and a large scale shell-model approach have been used to investigate these ``artificial&#39;&#

C. Yasuda, S. Todo, K. Harada, N. Kawashima

Critical behavior of the quantum phase transition of a site-diluted Heisenberg antiferromagnet on a square lattice is investigated by means of the quantum Monte Carlo simulation with the continuous-imaginary-time loop algorithm. Although the staggered spin correlation function decays in a power law with the exponent definitely depending on the spin size $S$,

Ludger Wenning, Martin H. Muser

The effect of surface curvature on the law relating frictional forces F with normal load L is investigated by molecular dynamics simulations as a function of surface symmetry, adhesion, and contamination. Curved, non-adhering, dry, commensurate surfaces show a linear dependency, F proportional to L, similar to dry flat commensurate or amorphous surfaces and

K. Held, I. A. Nekrasov, N. Blümer, V. I. Anisimov

The LDA+DMFT approach merges conventional band structure theory in the local density approximation (LDA) with a state-of-the-art many-body technique, the dynamical mean-field theory (DMFT). This new computational scheme has recently become a powerful tool for ab initio investigations of real materials with strong electronic correlations. In this paper an int

G. Tiana, R. A. Broglia

The time evolution of the formation probability of native bonds has been studied for designed sequences which fold fast into the native conformation. From this analysis a clear hierarchy of bonds emerge a) local, fast forming highly stable native bonds built by some of the most strongly interacting amino acids of the protein, b) non-local bonds formed late i

S. Capponi, F. F. Assaad

We present a detailed numerical study of spin and charge dynamics of the two-dimensional Kondo lattice model with hopping t and exchange J. At T=0 and J > 0, the competition between the RKKY interaction and Kondo effect triggers a quantum phase transition between magnetically ordered and disordered insulators: J_c/t = 1.45(5). The quasiparticle gap scales as

Uwe Grimm

The effects of an aperiodic order or a random disorder on phase transitions in statistical mechanics are discussed. A heuristic relevance criterion based on scaling arguments as well as specific results for Ising models with random disorder or certain kinds of aperiodic order are reviewed. In particular, this includes an exact real-space renormalization trea

A. Simopoulos, G. Kallias, E. Devlin, M. Pissas

1% $^{119}$Sn-doped La$_{0.5}$Ca$_{0.5}$MnO$_3$ was studied by Mössbauer spectroscopy, magnetic moment and resistivity measurements. The Mössbauer spectra below the charge-ordering temperature are explained with ferromagnetic (FM), antiferromagnetic (AF), and ferromagnetic spin cluster (CL) components. The magnetic and thermal hystereses of the relative inte

Anders Irbäck, Erik Sandelin

We study the statistical properties of hydrophobic/polar model sequences with unique native states on the square lattice. It is shown that this ensemble of sequences differs from random sequences in significant ways in terms of both the distribution of hydrophobicity along the chains and total hydrophobicity. Whenever statistically feasible, the analogous ca

D. Passerone, U. Tartaglino, F. Ercolessi, E. Tosatti

Due to particle conservation, Canonical Molecular Dynamics (MD) simulations fail in the description of surface phase transitions involving coverage or lateral density changes. However, a step on the surface can act effectively as a source or a sink of atoms, in the simulation as well as in real life. A single surface step can be introduced by suitably modify

T. Ono, T. Kato, H. Tanaka, A. Hoser

The spin-1/2 stacked triangular antiferromagnet CsCu$_{1-x}$Co$_x$Cl$_3$ with $0.015<x<0.032$ undergoes two phase transitions at zero field. The low-temperature phase is produced by the small amount of Co$^{2+}$ doping. In order to investigate the magnetic structures of the two ordered phases, the neutron elastic scattering experiments have been carried out

R. Mahendiran, A. Maignan, C. Martin, M. Hervieu

We investigated electrical and magnetic properties of the electron-doped manganites Ca1-xSmxMnO3 (0<x<0.2). Our results indicate the possibility of phase separation in electron doped manganites. The compounds with x = 0.13-0.15 show unusual difference between zero-field cooled and field-cooled resistivities which are not observed in lower compositions. Our r

Peter Gurin, Zsolt Gulacsi

Based on representations of the symmetric group $S_N$, explicit and exact Schrödinger equation is derived for $U=\infty$ Hubbard model in any dimensions with arbitrary number of holes, which clearly shows that during the movement of holes the spin background of electrons plays an important role. Starting from it, at T=0 we have analyzed the behaviour of the

Heung Sik Park, Hyunggyu Park

We investigate the effect of initial conditions on the dynamic exponents of the interacting monomer-monomer model with infinitely many absorbing states in one dimension. This model exhibits a directed Ising (DI) type transition from an active phase into an absorbing phase. In case of the directed percolation universality class, it has been reported that the

Sungchul Kwon, Hyunggyu Park

We study the effects of hard core (HC) interactions between different species of particles on two-species branching annihilating random walks with one offspring(BAW$_2$(1)). The single-species model belongs to the directed percolation (DP) universality class. In the BAW$_2$(1) model, a particle creates one particle of the same species in its neighborhood wit

A. Agarwal, S. G. Rajeev

We develop a finite temperature mean field theory in the path integral picture for an extremely dilute system of interacting Fermions in a plane. In the limit of short ranged interactions, the system is shown to undergo a phase transition to a superconducting regime. Unlike the well known BCS transition for metals, this phase transition is found to be very s

Matthew A. Kenworthy, Ian R. Parry, Keith Taylor

We present details of a prototype fiber feed for use on the Anglo-Australian Telescope (AAT) that uses a dedicated fiber-fed medium/high resolution (R > 10000) visible-band spectrograph to give integral field spectroscopy (IFS) of an extended object. A focal reducer couples light from the telescope to the close-packed lenslet array and fiber feed, allowing t

John E. Gizis

I discuss observations of two traditional age indicators, chromospheric activity and kinematics, in late-M and L dwarfs near the hydrogen-burning limit. The frequency and strength of chromospheric activity disappears rapidly as a function of temperature over spectral types M8-L4. There is evidence that young late-M and L dwarfs have weaker activity than olde

Jun-xian Wang, Ting-gui Wang, You-yuan Zhou

We present a detailed analysis of the iron K$α$ line variabilities in NGC 4151 by using long ASCA observation data obtained in May 1995. Despite the relatively small amplitude variations in the continuum flux, the iron K$α$ line flux and profile show dramatic variations. Particularly, the line profile changes from single peak to seeming double peaks and back

A. Alonso-Herrero, S. D. Ryder, J. H. Knapen

We present high-resolution near-infrared imaging obtained using adaptive optics and HST/NICMOS, and ground-based spectroscopy of the hot-spot galaxy NGC2903. Our near-infrared resolution imaging enables us to resolve the infrared hot spots into individual young stellar clusters or groups of these. The spatial distribution of the stellar clusters is not coinc

Peter Coles, Lung-Yih Chiang

In the standard picture of structure formation, initially random-phase fluctuations are amplified by non-linear gravitational instability to produce a final distribution of mass which is highly non-Gaussian and has highly coupled Fourier phases. Second-order statistics, such as the power spectrum, are blind to this kind of phase association. We discuss the i

D. Fernandez, X. Luri, F. Figueras, J. Torra

Two samples of O- and B-type stars and Cepheids with Hipparcos data have been used to characterize galactic rotation and spiral arm kinematics in the solar neighbourhood. An extensive set of simulations has been performed in order to assess the capabilities of the method and its sensitivity to sample errors and biases in the adopted parameters.

C. Henkel, R. Mauersberger, A. B. Peck, H. Falcke

The (J,K) = (1,1), (2,2), (3,3), and (4,4) inversion lines of ammonia (NH3) have been detected toward the nuclear 40&#39;&#39; sized bar of the nearby spiral galaxy Maffei 2. The relative intensities of the ammonia lines are characterized by a rotational temperature of 85 K. This is higher than rotational temperatures measured toward IC342 and most Galactic

Bryan Gaensler, John Dickey, Naomi McClure-Griffiths, Anne Green

The Southern Galactic Plane Survey (SGPS) is an HI and 1.4-GHz continuum survey of the 4th quadrant of the Galaxy at arcmin resolution. We present here results on linearly polarized continuum emission from an initial 28-square-degree Test Region for the SGPS, consisting of 190 mosaiced pointings of the Australia Telescope Compact Array, and covering the rang

Atsuo T. Okazaki

We study the characteristics of the outflow in disks of Be stars, based on the viscous decretion disk scenario. In this scenario, the matter ejected from the equatorial surface of the star drifts outward because of the effect of viscosity, and forms the disk. For simplicity, we adopt the alpha-prescription for the viscous stress, and assume the disk to be is

V. H. Chavushyan, R. Mújica, L. Carrasco, J. R. Valdés

The main goal of the FIRST-APM QSO Survey (FAQS) survey is to compile the most complete sample of Bright QSOs, located in the area covered by the Second Byurakan Survey (SBS). Here we report the first results of an ongoing study based on the cross-identification of the FIRST radio catalog and the APM optical catalog. The overlapping sky area between FIRST an

Andrea E. Gelatt, Deidre A. Hunter, J. S. Gallagher

We examine the star clusters in the irregular galaxy NGC 4449. We use a near-infrared spectrum and broad-band images taken with the HST to place a limit of 8--15 Myrs on the age of the bright central ojbect in NGC 4449. Its luminosity and size suggest that it is comparable to young super star clusters. However, there is a peculiar nucleated-bar structure at

Sabatino Sofia, Linghuai H. Li

Recent precise observations of solar global parameters are used to calibrate an upgraded solar model which takes into account magnetic fields in the solar interior. Historical data about sunspot numbers (from 1500 to the present) and solar radius changes (between 1715 and 1979) are used to compute solar variability on years to centuries timescales. The resul

Maarten Reyniers, Hans Van Winckel

Double lined spectroscopic binaries in an evolved stage of evolution are expected to be extremely rare since they must consist of equally luminous and thus almost equally evolved objects, which requires an extremely similar initial mass. In this contribution we discuss such rare double evolved SB2 system: HD172481. This binary includes an F-type post-AGB obj

L. Grenacher, R. Piffaretti, D. Puy, Ph. Jetzer

We discuss the influence of the finite extension and the geometry of clusters of galaxies, as well as of the polytropic temperature profile, on the determination of the Hubble constant.

Patrick Slane, John P. Hughes, Richard J. Edgar, Paul P. Plucinsky

The newly discovered supernova remnant G266.2-1.2 (RX J0852.0--0462), along the line of sight to the Vela SNR, was observed with ASCA for 120 ks. We find that the X-ray spectrum is featureless, and well described by a power law, extending to three the class of shell-type SNRs dominated by nonthermal X-ray emission. Like G347.3-0.5, this low-latitude remnant

A. C. Fabian, R. F. Mushotzky, P. E. J. Nulsen, J. R. Peterson

Strong evidence for cooling flows has been found in low resolution X-ray imaging and spectra of many clusters of galaxies. However high resolution X-ray spectra of several clusters from the Reflection Grating Spectrometer (RGS) on XMM-Newton now show a soft X-ray spectrum inconsistent with a simple cooling flow. The main problem is a lack of the emission lin

M. A. Gomez-Flechoso

We use SPH/N-body simulations to study the ram-pressure stripping of the gas of dwarf galaxies orbiting in a disc galaxy. The effects of the gaseous disc and halo on the satellites are analysed and the results are compared with the observations of the dwarf spheroidals (and dwarf irregulars) in the Local Group. The stripped gas is compared with the High Velo

Shuro Takano, Naomasa Nakai, Kentarou Kawaguchi, Toshiaki Takano

The ammonia (J,K) = (1,1), (2,2), (3,3), and (4,4) transitions at 23.7 -- 24.1 GHz region were searched for in a nearby galaxy Maffei 2 to study relation between molecular abundances and physical conditions in galaxies. The (1,1), (2,2), and (3,3) emission lines were clearly detected. The rotational temperatures and ortho-to-para abundance ratios obtained ar

Warrick J. Couch, Michael L. Balogh, Richard G. Bower, Ian Smail

We present the results of a wide-field survey for H-alpha emitting galaxies in the cluster AC114 at z=0.32. Spectra centred on H-alpha at the cluster redshift have been obtained for 586 galaxies to I~22 out to a radius around 2Mpc. At most, only ~10% of these were found to be H-alpha-emitting cluster members. These objects are predominantly blue and of late-

Evy Kersale, Pierre-Yves Longaretti, Guy Pelletier

We derive new stability criteria for purely MHD instabilities in rotating jets, in the framework of the ballooning ordering expansion. Quite unexpectedly, they involve a term which is linear in the magnetic shear. This implies that cylindrical configurations can be destabilized by a negative magnetic shear as well as by a favorable equilibrium pressure gradi

M. Tashiro, K. Makishima, N. Iyomoto, N. Isobe

A follow-up X-ray study was made of the west lobe of the radio galaxy Fornax A, (NGC 1316) based on new ASCA observations made in 1997 for 98 ks, and incorporating the previous observation in 1994 for 39 ks. The 0.7--10 keV spectrum of the emission can be described by a power-law of energy index 0.74 +/- 0.10, which agrees with the synchrotron radio index of

Patrick B. Hall

Faint quasar surveys are necessary complements to bright quasar surveys to remove the degeneracy between redshift and luminosity inherent in any single magnitude-limited sample. I discuss two ongoing surveys for faint quasars at 3.3<z<5 and 5<z<6 using imaging data from the Big Throughput Camera on the CTIO 4m. I also discuss a sample of faint spectroscopica

Hyesung Kang, George Lake, Dongsu Ryu

Many models of globular cluster formation assume the presence of cold dense clouds in early universe. Here we re-examine the Fall & Rees (1985) model for formation of proto-globular cluster clouds (PGCCs) via thermal instabilities in a protogalactic halo. We first argue, based on the previous study by others, that under the protogalactic environments only no

A . Nordlund, O. E. Rognvaldsson

We have studied the fate of initial magnetic fields in the hot halo gas out of which the visible parts of galaxies form, using three-dimensional numerical MHD-experiments. The halo gas undergoes compression by several orders of magnitude in the subsonic cooling flow that forms the cold disk. The magnetic field is carried along and is amplified considerably i

A. Kaminski, L. I. Glazman

We study inelastic electron-electron scattering mediated by the exchange interaction of electrons with magnetic impurities, and find the kernel of the corresponding two-particle collision integral. In a wide region of parameters, the kernel K is proportional to the inverse square of the transferred energy, $K\propto J^4/E^2$. The exchange constant J is renor

Walter Rantner, Xiao-Gang Wen

We propose to describe the spin fluctuations in the normal state of underdoped high $T_{c}$ superconductors as a manifestation of an algebraic spin liquid. We have performed calculations within the slave-boson model to support our proposal. Under the spin-charge separation picture, the normal state (the spin-pseudogap phase) is described by massless Dirac fe

M. N. Sergeenko

The classical limit of wave quantum mechanics is analyzed. It is shown that the general requirements of continuity and finiteness to the solution $ψ(x)=Ae^{iϕ(x)}+ Be^{-iϕ(x)}$, where $ϕ(x)=\frac 1\hbar W(x)$ and $W(x)$ is the reduced classical action of the physical system, result in the asymptote of the exact solution and general quantization condition for

Arjun Berera, Christopher Gordon

The initial condition problem of inflation is examined from the perspective of both spacetime embedding and scalar field dynamics. The spacetime embedding problem is solved for arbitrary initial spatial curvature Omega, which generalizes previous works that primarily treat the flat case Omega=1. Scalar field dynamics that is consistent with the embedding con

J. Gamboa, M. Loewe, J. C. Rojas

A general non-commutative quantum mechanical system in a central potential $V=V(r)$ in two dimensions is considered. The spectrum is bounded from below and for large values of the anticommutative parameter $θ$, we find an explicit expression for the eigenvalues. In fact, any quantum mechanical system with these characteristics is equivalent to a commutative

L. Dolan

This review gives results on vertex operators for the Type IIB superstring in an AdS3 x S3 background with Ramond-Ramond flux, which were presented at Strings 2000. Constraint equations for these vertex operators are derived, and their components are shown to satisfy the supergravity linearized equations of motion for the six-dimensional (2,0) theory of a su

D. Belitz, T. R. Kirkpatrick, Maria Teresa Mercaldo, Sharon L. Sessions

The quantum critical behavior of disordered itinerant ferromagnets is determined exactly by solving a recently developed effective field theory. It is shown that there are logarithmic corrections to a previous calculation of the critical behavior, and that the exact critical behavior coincides with that found earlier for a phase transition of undetermined na

Moshe Gai

The 7Be(p,gamma)8B reaction is one of the major source of uncertainties in estimating the 8B solar neutrino flux and is critical for undertsanding the Solar Neutrino Problem and neutrinos. The main source of uncertainty is the existence of conflicting data with different absolute normalization. Attempts to measure this reaction rate with 7Be beams are under

Ahmed Jellal

An approach is proposed enabling to effectively describe the behaviour of a bosonic system. The approach uses the quantum group $GL_{p,q}(2)$ formalism. In effect, considering a bosonic Hamiltonian in terms of the $GL_{p,q}(2)$ generators, it is shown that its thermodynamic properties are connected to deformation parameters $p$ and $q$. For instance, the ave

Ahmed Jellal, Mohammed Daoud

The paper is concerned with thermostatistics of both $D$-dimensional Bose and Fermi ideal gases in a confining potential of type $Ar^{n}+Br^{-n}$. The investigation is performed in the framework of the semiclassical approximation. Some physical quantities for such systems are derived, like density of states, density profiles and number of particles. Bose-Ein

Oleg Andreev

We discuss what information can be safely extracted from background independent off-shell string theory. The major obstacle in doing so is that renormalization conditions of the underlying world-sheet theories are not exactly known. To get some insight, we first consider the tachyon and gauge field backgrounds and carry out computations in different renormal

Alessandro Tomasiello

We investigate further on the correspondence between branes on a Calabi-Yau in the large volume limit and in the orbifold limit. We conjecture a new procedure which improves computationally the McKay correspondence and prove it in a non trivial example. We point out the relevance of helices and try to draw some general conclusions about Beilinson theorem and

A. A. Andrianov, R. Tarrach, J. Taron

We consider departures from hamiltonian dynamics in the evolution of neutral kaons due to their interactions with environment that generate entanglement among them. We propose a phenomenological model of stochastic re-scattering and estimate the coefficients of the effective hamiltonian and decoherence terms. Finally we analyze the interplay between the weak

A. N. Cillis, S. J. Sciutto

The objective of this work is to report on the influence of muon interactions on the development of air showers initiated by astroparticles. We make a comparative study of the different theoretical approaches to muon bremsstrahlung and muonic pair production interactions. A detailed algorithm that includes all the relevant characteristics of such processes h

Nathalie Deruelle, Tomas Dolezel, Joseph Katz

We consider cosmological models where the universe, governed by Einstein&#39;s equations, is a piece of a five dimensional double-sided anti-de Sitter spacetime (that is, a &#34;$Z_2$-symmetric bulk&#34;) with matter confined to its four dimensional Robertson-Walker boundary or &#34;brane&#34;. We study the perturbations of such models. We use conformally mi

Cristina Manuel, Michel H. G. Tytgat

We study the asymmetry between the vector current and axial-vector current correlators in the colour-flavour locking (CFL) phase of QCD at finite density. Using Weinberg&#39;s sum rules, we compute the decay constant $f_π$ of the Goldstone modes and find agreement with previous derivations. Using Das&#39;s sum rule, we also estimate the contribution of elect

Ph. Chomaz, F. Gulminelli, V. Duflot

We propose a definition of phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. This generalizes all the definitions based on the curvature anomalies of thermodynamical potentials and provides a natural definition of order parameters. The proposed definition is directly operational from the e

Nevena Ilieva, Walter Thirring

We study the quantum theory of two-dimensional electrons in a magnetic field and an electric field generated by a homogeneous background. The dynamics separates into a microscopic and macroscopic mode. The latter is a circular Hall current which is described by a chiral quantum field theory. It is shown how in this second quantized picture a Laughlin-type wa

A. Dimitropoulos, L. P. Grishchuk

The important studies of Peebles, and Bond and Efstathiou have led to the formula C_l = const/[l(l +1)] aimed at describing the lower order multipoles of the CMBR temperature variations caused by density perturbations with the flat spectrum. Clearly, this formula requires amendments, as it predicts an infinitely large monopole C_0, and a dipole moment C_1 on

J. Alexandre, K. Farakos, G. Koutsoumbas

We solve the Schwinger-Dyson equations for (2+1)-dimensional QED in the presence of a strong external magnetic field. The calculation is done at finite temperature and the fermionic self energy is not supposed to be momentum-independent, which is the usual simplification in such calculations. The phase diagram in the temperature-magnetic field plane is deter

SDSS Collaboration, Francisco J. Castander, Robert C. Nichol, Aronne Merrelli

On 26 May 1999, one of the Sloan Digital Sky Survey (SDSS) fiber-fed spectrographs saw astronomical first light. This was followed by the first spectroscopic commissioning run during the dark period of June 1999. We present here the first hour of extra-galactic spectroscopy taken during these early commissioning stages: an observation of the Coma cluster of

Rennan Barkana, Abraham Loeb

The formation of the first stars and quasars marks the transformation of the universe from its smooth initial state to its clumpy current state. In popular cosmological models, the first sources of light began to form at redshift 30 and reionized most of the hydrogen in the universe by redshift 7. Current observations are at the threshold of probing the hydr

Michael Stay

Withdrawn; replaced by longer, more detailed paper quant-ph/0010065.

E. Elizalde

An alternative kind of deleting/erasing operation is introduced which differs from the commonly used {\it controlled-not} (C-not) conditional logical operation $-$to flip to a standard, `zero&#39; value the (classical or quantum) state of the last copy in a chain, in a deletion process. It is completely reversible, in the classical case, possessing a most na

Shantilal G. Goradia

I combine the effects of Planck length, general relativity and Newtonian gravity in one equation, to come up with a semi-classical model of gravity in the form of deviation from Newtonian gravity. Einstein explained nuclear forces in terms of gravity (Ref. 2). This reference is explicit in expressing Einstein&#39;s attempts and describes them as misguided. M

M. Tushentsov, F. Cattani, A. Kim, D. Anderson

Two scenarios for the penetration of relativistically intense laser radiation into an overdense plasma, accessible by self-induced transparency, are presented. For supercritical densities less than 1.5 times the critical one, penetration of laser energy occurs by soliton-like structures moving into the plasma. At higher background densities laser light penet

H. Mouri, A. Hori, Y. Kawashima

The streamwise and transverse velocities are measured simultaneously in grid turbulence at Reynolds numbers 100-300. We extract typical intermittency patterns, which are consistent with velocity profiles of Burgers and Lamb-Oseen vortices. The radii of these vortex tubes are estimated to be several of the Kolmogorov length.

S. I. Bityukov, N. V. Krasnikov

A results of numerical procedure for construction of confidence intervals for parameter of Poisson distribution for signal in the presence of background which has Poisson distribution with known value of parameter are presented. It is shown that the described procedure has both Bayesian and frequentist interpretations.

A. R. Taurines, C. A. Z. Vasconcellos, M. Malheiro, M. Chiapparini

We introduce in this work a class of relativistic models for nuclear matter and neutron stars which exhibits a parameterization, through mathematical constants, of the non-linear meson-baryon couplings. For appropriate choices of the parameters, it recovers current QHD models found in the literature: Walecka and the Zimanyi and Moszkowski models (ZM and ZM3)

J. Dias de Deus, M. T. Peña, J. C. Seixas

Subthreshold events (pion production, for instance) at energies $E< m_π$ are treated as rare events. The associated multiplicity distribution $P_c (n)$ and the unconstrained distribution P(n), when there is no rare event-trigger, are related by the model independent relation $P_c (n) = {n^2 \over \average{n^2}} P(n)$. This relation, and in particular its imp

H. Garcilazo, M. T. Peña

We have solved the Faddeev equations for $ηd$ elastic scattering using realistic separable interactions for the $NN$ and coupled $ηN$-$πN$ subsystems. We found that including explicitly the pion channel in the integral equations drastically reduces the attraction that is present in the system. As a consequence, the existence of a $ηNN$ quasibound state is ex

E. Truhlik, J. Smejkal, F. C. Khanna

Using modern data, we first refit constants needed to complete an anomalous pi-rho-omega-a_1 Lagrangian obtained within the approach of hidden local symmetries. Then we derive from this Lagrangian electromagnetic isoscalar rho-pi-gamma and rho-a_1-gamma currents needed in calculations of the deuteron electromagnetic form factors at large momentum transfers.

R. C. Johnson

A six-dimensional Rossler-Lorenz hybrid has two coexistent attractors. Both, either or neither may be strange.

Semion Gutman

A multilayered particle is illuminated by plane acoustic or electromagnetic waves of one or several frequencies. We consider the inverse scattering problem for the identification of the layers and of the refraction coefficients of the scatterer in a non-Born region of scattering. Local deterministic and global probabilistic minimization methods are studied.

Sami I. Muslih

The path integral formulation of constrained systems leads to obtain the equations of motion as total differential equations in many variables. If these equations are integrable then one can constuct a valid and a canonical phase space coordinates. The path integral is obtained as an integration over the canonical phase space coordinates. This approach is ap

Senya Shlosman

We present the geometric solutions to some variational problems of statistical mechanics and combinatorics. Together with the Wulff construction, which predicts the shape of the crystals, we discuss the construction which exhibits the shape of a typical Young diagram and of a typical skyscraper.

Joel Merker

A CR generic real analytic CR manifold M carries two families of Segre varieties and conjugate Segre varieties. We observe in this article that their complexifications give rise to two families of foliations of the complexification of M which coincide with the flow foliations induced by the complexified CR (1,0) and (0,1) vector fields tangent to M. As an ap

Henk Bruin, Benoit Saussol, Serge Troubetzkoy, Sandro Vaienti

We prove that return time statistics of a dynamical system do not change if one passes to an induced (i.e. first return) map. We apply this to show exponential return time statistics in i) smooth interval maps with nowhere-dense critical orbits and ii) certain interval maps with neutral fixed points. The method also applies to iii) certain quadratic maps of

Tatsuhiko Yagasaki

Suppose M is a noncompact connected PL 2-manifold. In this paper we study the topological property of the triple (H(M)_0, H^PL(M)_0, H^PL, c(M)_0), where H(M)_0 is the identity component of the homeomorphism group {\cal H}(M) of M with the compact-open topology, and H^PL(M)_0 and H^PL, c(M)_0 are the identity components of the subgroups consisting of PL-home

Tatsuhiko Yagasaki

Suppose M is a noncompact connected PL 2-manifold and let H(M)_0 denote the identity component of the homeomorphism group of M with the compact-open topology. In this paper we classify the homotopy type of H(M)_0 by showing that {\cal H}(M)_0 has the homotopy type of the circle if M is the plane, an open or half open annulus, or the punctured projective plan

Tatsuhiko Yagasaki

Let M be a PL 2-manifold and X be a compact subpolyhedron of M and let E(X, M) denote the space of embeddings of X into M with the compact-open topology. In this paper we study an extension property of embeddings of X into M and show that the restriction map from the homeomorphism group of M to E(X, M) is a principal bundle. As an application we show that if

Thomas W. Cusick, Pantelimon Stanica

We study the nonlinearity and the weight of the rotation-symmetric (RotS) functions defined by Pieprzyk and Qu. We give exact results for the nonlinearity and weight of 2-degree RotS functions with the help of the semi-bent functions and we give the generating function for the weight of the 3-degree RotS function. Based on the numerical examples and our obse

Pantelimon Stanica

First, we construct a class of functions with good local avalanche characteristics, but bad global avalanche characteristics. We also derive some bounds for the nonlinearity of such functions. It improves upon the results of Son et al., and Sung et al. In our second result we construct a class of highly nonlinear balanced functions with good local and global

Arjeh M. Cohen, David B. Wales

Recent results on the linearity of braid groups are extended in two ways. We generalize the Lawrence Krammer representation as well as Krammer&#39;s faithfulness proof for this linear representation to Artin groups of finite type.

Yanguang Charles Li

In Part I of our study on 2D Euler equation, we established the spectral theorem for a linearized 2D Euler equation. We also computed the point spectrum through continued fractions, and identified the eigenvalues with nonzero real parts. In this Part II of our study, first we discuss the Lax pairs for both 2D and 3D Euler equations. The existence of Lax pair

Witold Jarnicki

For a domain $D\subset{\Bbb C}$ the Kobayashi--Royden $κ$ and Hahn $h$ pseudometrics are equal iff $D$ is simply connected. Overholt showed that for $D\subset{\Bbb C}^n$, $n\geq3$, we have $h_D\equivκ_D$. Let $D_1,D_2\subset{\Bbb C}$. The aim of this paper is to show that $h_{D_1\times D_2}\equivκ_{D_1\times D_2}$ iff at least one of $D_1$, $D_2$ is simply c