July 1998 arXiv papers

Soo-Jong Rey

D-instantons of Type IIB string theory are Ramond-Ramond counterpart of Giddings-Strominger wormholes connecting two asymptotic regions of spacetime. Such wormholes, according to Coleman, might lead to spacetime topology change, third-quantized baby universes and probabilistic determination of fundamental coupling parameters. Utilizing correspondence between

F. D. A. Hartwick

We use observations and evolutionary models of local objects to interpret a recent determination of the star-formation history of the universe. By fitting the global star-formation rate, the model predicts the ratio of spheroid to disk mass of $\sim$1, an intergalactic medium (IGM) whose mass is $\sim$2.3 times the mass in stars, and whose metallicity is $\s

Pietro Santorelli, Egidio Scrimieri

We present a new method to solve in a semianalytical way the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations at NLO order in the x-space. The method allows to construct an evolution operator expressed in form of a rapidly convergent series of matrices, depending only on the splitting functions. This operator, acting on a generic initial distri

S. Carlip, J. E. Nelson

The role of the modular group in the holonomy representation of (2+1)-dimensional quantum gravity is studied. This representation can be viewed as a "Heisenberg picture", and for simple topologies, the transformation to the ADM "Schr{ö}dinger picture" may be found. For spacetimes with the spatial topology of a torus, this transformation and a

V. Dzhunushaliev, D. Singleton

In this paper spherically symmetric solutions to 5D Kaluza-Klein theory, with ``electric'' and/or ``magnetic'' fields are investigated. It is shown that the global structure of the spacetime depends on the relation between the ``electrical'' and ``magnetic'' Kaluza-Klein fields. For small ``magnetic'' field we find a w

M. Dakna, J. Clausen, L. Knoll, D. -G. Welsch

We show that any single-mode quantum state can be generated from the vacuum by alternate application of the coherent displacement operator and the creation operator. We propose an experimental implementation of the scheme for traveling optical fields, which is based on field mixings and conditional measurements in a beam splitter array, and calculate the pro

Enrico Meggiolaro

We discuss the results obtained by fitting the lattice data of the gauge-invariant field strength correlators in QCD with some particular functions which are commonly used in the literature in some phenomenological approaches to high-energy hadron-hadron scattering. A comparison is done with the results obtained in the original fits to the lattice data.

F. Cano, M. Traini

Modifications to the nucleon electric polarizability induced by pion and sigma exchange in the q-q potentials are studied by means of sum rule techniques within a non-relativistic quark model. Contributions from meson exchange interactions are found to be small and in general reduce the quark core polarizability for a number of hybrid and one-boson-exchange

P. Chiappetta, G. J. Gounaris, J. Layssac, F. M. Renard

We propose a class of forward-backward asymmetries with respect to the subprocess c.m. scattering angle in $V$+jet production at hadron colliders, with V being any of (W, Z, $γ$, H), which are directly proportional to the gluon distribution $g(x)$. The informations that these asymmetries can provide are complementary of those reachable from measurements of t

J. E. Garcia-Ramos, C. E. Alonso, J. M. Arias, P. Van Isacker

Double-$γ$ vibrations in deformed nuclei are studied in the context of the interacting boson model with special reference to their anharmonic character. It is shown that large anharmonicities can be obtained with interactions that are (at least) of three-body nature between the bosons. As an example the $γ$ vibrations of the nucleus $^{166}_{\phantom{0}68}$E

Angelica de Oliveira-Costa, Max Tegmark, Lyman Page, Steven Boughn

We cross-correlate a 19 GHz full sky Cosmic Microwave Background (CMB) survey with other maps to quantify the foreground contribution. Correlations are detected with the Diffuse Infrared Background Experiment (DIRBE) 240, 140 and 100 micron maps at high latitudes (|b|>30degrees), and marginal correlations are detected with the Haslam 408 MHz and the Reich &

Andreas Winter

This note will introduce some notation and definitions for information theoretic quantities in the context of quantum systems, such as (conditional) entropy and (conditional) mutual information. We will employ the natural C*-algebra formalism, and it turns out that one has an allover dualism of language: we can define everything for (compatible) observables,

P. Sirabella, A. Giuliani, A. Colosimo

This paper reports about an approach to the classification of proteins' primary structures taking advantage of the Self Organizing Maps algorithm and of a numerical coding of the aminoacids based upon their physico-chemical properties. Hydrophobicity, volume, surface area, hydrophilicity, bulkiness, refractivity and polarity were subjected to a Principal

Bao-An Li, C. M. Ko

An attractive, energy-dependent mean-field potential for baryons is introduced in order to generate a soft region in the nuclear equation-of-state, as suggested by recent lattice QCD calculations of baryon free matter at finite temperature. Based on a hadronic transport model, we find that although this equation-of-state has negligible effects on the inclusi

R. A. Arndt, I. I. Strakovsky, R. L. Workman, M. M. Pavan

We present the results of energy-dependent and single-energy partial-wave analyses of pi-N elastic scattering data with laboratory kinetic energies below 2.1 GeV. We have considered the effect of adding dispersion-relation constraints required for a more reliable extraction of the pi-N sigma term. The results of these new fits are compared with those generat

Wojciech Broniowski, Brigitte Hiller

In-medium sum rules following from the chiral charge algebra of QCD are reviewed, and new sum rules are derived. The new sum rules relate the I^G(J^{PC})=1^-(0^{++}) excitations (quantum numbers of a_0(980)) to the scalar and isovector densities, and are nontrivial for the isospin-asymmetric medium. We present an extensive illustration of the sum rules with

R. F. Bishop, R. Guardiola, I. Moliner, J. Navarro

We study the extension of our translationally invariant treatment of few-body nuclear systems to include tensor forces and correlations. It is shown that a direct application of our method is not as successful for realistic V6 interactions as our previous results for V4 potentials suggested. We investigate the cause in detail for the case of $^4$He, and show

Th. A. Rijken, V. G. J. Stoks, Y. Yamamoto

A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. An important innovation with respect to the original soft-core potential is the assignment o

A. Frydryszak, J. Lukierski, P. Minnaert, M. Mozrzymas

Three classes of classical r-matrices for sl(4,C) algebra are constructed in quasi-Frobenius algebra approach. They satisfy CYBE and are spanned respectively on 8,10,12 generators. The o(4,2) reality condition can be imposed only on the eight dimensional r matrices with dimension-full deformation parameters. Contrary to the Poincare algebra case, it appears

Natig M. Atakishiyev, Elchin I. Jafarov, Shakir M. Nagiev, Kurt B. Wolf

Meixner oscillators have a ground state and an `energy' spectrum that is equally spaced; they are a two-parameter family of models that satisfy a Hamiltonian equation with a {\it difference} operator. Meixner oscillators include as limits and particular cases the Charlier, Kravchuk and Hermite (common quantum-mechanical) harmonic oscillators. By the Somm

Glenn G. Chappell

A partition of a finite poset into chains places a natural upper bound on the size of a union of k antichains. A chain partition is k-saturated if this bound is achieved. Greene and Kleitman proved that, for each k, every finite poset has a simultaneously k- and k+1-saturated chain partition. West showed that the Greene-Kleitman Theorem is best-possible in a

Vsevolod Shevchishin

We show that under mild boundary conditions the moduli space of non-compact curves on a complex surface is (locally) an analytic subset of a ball in a Banach manifold, defined by {\it finitely} many holomorphic function.

Zurab Kakushadze

We briefly review the status of three-family grand unified string models.

Supriya Kar, Yoichi Kazama

A path integral formalism is developed to study the interaction of an arbitrary curved Dirichlet (D-) string with elementary excitations of the fundumental (F-) string in bosonic string theory. Up to the next to leading order in the derivative expansion, we construct the properly renormalized vertex operator, which generalizes the one previously obtained for

Stephen Parke

Unlike other examples of fermion pair production in e+ e- collisions, we show that top-quark pairs are produced in an essentially unique spin configuration in polarized e+ e- colliders at all energies. Since the directions of the electroweak decay products of polarized top-quarks are strongly correlated to the top-quark spin axis, this unique spin configurat

B. Dutta

We consider the scenarios of the GMSB models in which the dominant signal for supersymmetry at the Tevatron are the events having two or three $τ$ leptons with high $p_T$ accompanied by large missing transverse energy. This signal is very different from the multijet or multileptons (involving $e$ and/or $μ$ only) in the usual supergravity models or the photo

F. Caravaglios, M. L. Mangano, M. Moretti, R. Pittau

We present an algorithm to evaluate the exact, tree-level matrix elements for multi-parton processes in QCD. We tested this technique, based on the recursive evaluation of the S-matrix, on processes such as gg -> n gluons and q qbar -> n gluons, with n up to 9. The summation over colour configurations is designed to allow the construction of parton-level eve

Andre Sopczak

A preliminary combined mass limit of about 90 GeV has been reported for the Minimal Standard Model Higgs boson from the 183 GeV data taken in 1997, with a total luminosity of about 200 pb-1. Similar mass limits have been reported from the individual LEP experiments based on the first 1998 data at 189 GeV with up to 40 pb-1 each. For the first time the LEP ex

T. Hahn, M. Perez-Victoria

Two program packages are presented for evaluating one-loop amplitudes. They can work either in dimensional regularization or in constrained differential renormalization. The latter method is found at the one-loop level to be equivalent to regularization by dimensional reduction.

G. Rasche, A. Gashi

We give the modern derivation of Deser's formula using analytic continuation of the scattering amplitude as a function of momentum. The electromagnetic corrections to the pionium lifetime are given as evaluated in a potential model.

S. Scherer

Virtual Compton scattering off nucleons and pions at low energies is discussed. Predictions for the generalized polarizabilities of the nucleon are presented within the framework of heavy-baryon chiral perturbation theory and the linear sigma model. First results for the generalized polarizabilities of the charged pion in chiral perturbation theory at ${\cal

Toby Falk

We examine the current state of neutralino dark matter and consider how the LEP constraints on the Minimal Supersymmetric Standard Model parameters are squeezing the available dark matter regions. We also show how cosmological constraints augment bounds coming from collider searches to further constrain the MSSM parameter space.

V. V. Kiselev

A model is constructed for a chiral abelian gauge-interaction of fermions and a potential of three higgses, so that the potential possesses a discrete symmetry of the vacuum state, which provides the introduction of three generations for the fermions. For the model including charged currents, a matrix of the flavor mixing is described, and a phase giving the

D. Becirevic, Ph. Boucaud, J. P. Leroy, V. Lubicz

We have computed the light quark masses using the O(a^2) improved Alpha action, in the quenched approximation. The renormalized masses have been obtained non-perturbatively. By eliminating the systematic error coming from the truncation of the perturbative series, our procedure removes the discrepancies, observed in previous calculations, between the results

M. Baig, J. Clua, H. Fort

We present a high statistics analysis of the pure gauge compact U(1) lattice theory using the the world-sheet or Lagrangian loop representation. We have applied a simulation method that deals directly with (gauge invariant) integer variables on plaquettes. As a result we get a significant amelioration of the simulation that allows to work with large lattices

M. Gockeler, R. Horsley, H. Oelrich, H. Perlt

We investigate the nonperturbative renormalisation of composite operators in lattice QCD restricting ourselves to operators that are bilinear in the quark fields. These include operators which are relevant to the calculation of moments of hadronic structure functions. The computations are based on Monte Carlo simulations using quenched Wilson fermions.

N. Hayashi, Y. Goto, N. Saito

We describe the foreseen spin physics of the polarized proton-proton collider at RHIC. The study of the spin structure of the nucleon at RHIC is unique and complementary to the traditional polarized DIS experiments. The sensitivities of the gluon polarization measurement via prompt photon production and anti-quark polarization measurement using W production

The MACRO Collaboration, M. Ambrosio et al

An experimental study of the production of up-going charged particles in inelastic interactions of down-going underground muons is reported, using data obtained from the MACRO detector at the Gran Sasso Laboratory. In a sample of 12.2 10^6 single muons, corresponding to a detector livetime of 1.55 y, 243 events are observed having an up-going particle associ

Elad Shopen, Yigal Meir

The fluctuations in the spacing of the tunneling resonances through a quantum dot have been studied in the quantum Hall regime. Using the fact that the ground-state of the system is described very well by the Laughlin wavefunction, we were able to determine accurately, via classical Monte Carlo calculations, the amplitude and distribution of the peak-spacing

R. Folk, Yu. Holovatch

We study the phase transition to the superconducting state taking into account the fluctuations of the order parameter and of the vector magnetic field and discuss the question of the order of transition occuring in this model. We use the field-theoretical renormalization group approach and consider in two-loop approximation the gauge model for a superconduc

Marc Mezard, Giorgio Parisi

We propose a first principle computation of the thermodynamics of simple fragile glasses starting from the two body interatomic potential. A replica formulation translates this problem into that of a gas of interacting molecules, each molecule being built of $m$ atoms, and having a gyration radius (related to the cage size) which vanishes at zero temperature

P. Hadley, E. Delvigne, E. H. Visscher, S. Lahteenmaki

A current due to a tunneling event that involves three times the charge of an electron was observed in the current - voltage characteristics of a superconducting single-electron tunneling transistor. In this tunnel event, a Cooper pair tunnels through one tunnel barrier simultaneously with a quasiparticle that tunnels through a second tunnel barrier which is

Martin Fuchs, Matthias Scheffler

The package fhi98PP allows one to generate norm-conserving pseudopotentials adapted to density-functional theory total-energy calculations for a multitude of elements throughout the periodic table, including first-row and transition metal elements. The package also facilitates a first assessment of the pseudopotentials' transferability, either in semiloc

Zvonko Glumac, Katarina Uzelac

The first-order phase transition in the three-state Potts model with long-range interactions decaying as $1/r^{1+σ}$ has been examined by numerical simulations using recently proposed Luijten-Blöte algorithm. By applying scaling arguments to the interface free energy, the Binder's fourth-order cumulant, and the specific heat maximum, the change in the ch

K. Uzelac, Z. Glumac

The first-order phase transition in the one-dimensional $q$-state Potts model with long-range interactions decaying with distance as $1/r^{1+σ}$ has been studied by Monte Carlo numerical simulations for $0 < σ\le 1$ and integer values of $q > 2$. On the basis of finite-size scaling analysis of interface free energy $ΔF_L$, specific heat and Binder&#39;s four

Erik Luijten, Kurt Binder

We present an accurate numerical determination of the crossover from classical to Ising-like critical behavior upon approach of the critical point in three-dimensional systems. The possibility to vary the Ginzburg number in our simulations allows us to cover the entire crossover region. We employ these results to scrutinize several semi-phenomenological cros

Qijin Chen, Ioan Kosztin, Boldizsar Janko, K. Levin

We propose a theoretical description of the superconducting state of under- to overdoped cuprates, based on the short coherence length of these materials and the associated strong pairing fluctuations. The calculated $T_c$ and the zero temperature excitation gap $Δ(0)$, as a function of hole concentration $x$, are in semi-quantitative agreement with experime

Y. Alhassid, M. Gokcedag, A. D. Stone

We derive the finite temperature conductance peak distributions and peak-to-peak correlations for quantum dots in the Coulomb blockade regime assuming the validity of random matrix theory. The distributions are universal, depending only on the symmetry class and the temperature measured in units of the mean level spacing, $Δ$. When the temperature is compara

Maxim Olshanii

We derive a simple formula for the finite-temperature shifts of the collective excitations of a Bose-Einstein condensate. To test the validity of our treatment we apply it to explain the anomalous behavior of the ``m=2&#39;&#39; excitation frequency in the recent JILA experiments (D. S. Jin et al, PRL, 78 (1997) 764), where this frequency does not approach i

Hans van Halteren, Jakub Zavrel, Walter Daelemans

In this paper we examine how the differences in modelling between different data driven systems performing the same NLP task can be exploited to yield a higher accuracy than the best individual system. We do this by means of an experiment involving the task of morpho-syntactic wordclass tagging. Four well-known tagger generators (Hidden Markov Model, Memory-

Kim Binsted

In this paper we present early work on an animated talking head commentary system called {\bf Byrne}\footnote{David Byrne is the lead singer of the Talking Heads.}. The goal of this project is to develop a system which can take the output from the RoboCup soccer simulator, and generate appropriate affective speech and facial expressions, based on the charact

A. Gamba, I. V. Kolokolov

We compute analytically the probability distribution function ${\cal P}(ε)$ of the dissipation field $ε=(\nabla θ)^{2}$ of a passive scalar $θ$ advected by a $d$-dimensional random flow, in the limit of large Peclet and Prandtl numbers (Batchelor-Kraichnan regime). The tail of the distribution is a stretched exponential: for $ε\to \infty$, $\ln {\cal P}(ε)\s

Andrew Gould

One of the major limitations of microlensing observations toward the Large Magellanic Cloud (LMC) is the low rate of event detection. What can be done to improve this rate? Is it better to invest telescope time in more frequent observations of the inner high surface-brightness fields, or in covering new, less populated outer fields? How would a factor 2 impr

T. Yaqoob, I. M. George, T. J. Turner, K. Nandra

We report the results from an ASCA observation of the high-luminosity, radio-loud quasar PKS 0637-752 (redshift 0.654), covering the 0.8-15 keV band in the quasar-frame. We find the source to have a luminosity ~10^46 erg/s in the 2-10 keV band, a factor of ~3 lower than during a previous GINGA observation. The continuum appears to be well modeled by a simple

Paolo Gondolo

A sophisticated analysis of EGRET data has found evidence for gamma-ray emission from the galactic halo. I entertain the possibility that part of the EGRET signal is due to WIMP annihilations in the halo. I show that a viable candidate with the required properties exists in a model with an extended Higgs sector. The candidate has a mass of 2--4 GeV, a relic

Heinz Andernach

A subjective overview of Internet resources for radio-astronomical information is presented. Basic observing techniques and their implications for the interpretation of publicly available radio data are described, followed by a discussion of existing radio surveys, their level of optical identification, and nomenclature of radio sources. Various collections

P. Hoeflich, J. C. Wheeler, L. Wang

The recent discovery of the unusual supernova SN1998bw and its apparent correlation with the gamma-ray burst GRB 980425 has raised new issues concerning both the GRB and SNe. SN1998bw was unusually bright at maximum light and expansion velocities were large making SN1998bw a possible candidate for a &#34;hypernova&#34; with explosion energies exceeding 10^{5

Gustavo Medina Tanco

The possibility that the magnetic field is strongly correlated with the large-scale structure of the universe has been recently proposed in the literature. In this scenario the intergalactic magnetic field has a strong (m Gauss) regular component spanning tens of Mpc. This could have severe consequences on the propagation of ultra-high energy cosmic rays, an

Paolo Padovani, Tim Kimball

We describe a new WWW interface that allows the cross-correlation of an Active Galactic Nuclei catalog with various archives (HST, IUE, EUVE) available at the Multimission Archive at the Space Telescope Science Institute. Details of the catalog and the interface are provided.

HEGRA collaboration, L. Padilla, B. Funk, H. Krawczynski

A search for gamma-ray bursts (GRBs) above 20 TeV within the field of view (1 sr) of the HEGRA AIROBICC Cherenkov array (29N, 18W, 2200 m a.s.l.) has been performed using data taken between March 1992 and March 1993. The search is based on an all-sky survey using four time scales, 10 seconds, 1 minute, 4 minutes and 1 hour. No evidence for TeV-emission has b

H. J. Mo, Shude Mao, Simon D. M. White

The number density and clustering properties of Lyman-break galaxies (LBGs) are consistent with them being the central galaxies of the most massive dark halos present at z~3. This conclusion holds in all currently popular hierarchical models for structure formation, and is almost independent of the global cosmological parameters. We examine whether the sizes

Yoshiaki Sofue, Akihiko Tomita, Yoshinori Tutui, Mareki Honma

We have obtained optical CCD spectroscopy along the major axes of 22 nearby spiral galaxies of Sb and Sc types in order to analyze their rotation curves. By subtracting the stellar continuum emission, we have obtained position velocity (PV) diagrams of the H alpha and [NII] lines. We point out that the H alphaline is often superposed by a broad stellar absor

Marco Chiaberge, Gabriele Ghisellini

Blazars are characterized by large amplitude and fast variability, indicating that the electron distribution is rapidly changing, often on time scales shorter than the light crossing time. We study the time dependent behavior of the electron distribution after episodic electron injection phases, and calculate the observed synchrotron and self Compton radiati

Claudia Maraston

A new tool for the Evolutionary Synthesis of Stellar Populations (EPS) is presented, which is based on three independent matrices, giving respectively: 1) the fuel consumption during each evolutionary phase as a function of stellar mass; 2) the typical temperatures and gravities during such phases; 3) colours and bolometric corrections as functions of gravit

G. Ramsay, P. J. Wheatley

We present low--medium resolution optical spectroscopy of the eclipsing AM Her system MN Hya (RX J0929--24). We determine the magnetic field strength at the primary accretion region of the white dwarf to be 42MG from the spacing of cyclotron features visible during ~0.4--0.7. From spectra taken during the eclipse we find that the secondary has a M3--4 spectr

M. Scodeggio, L. F. Olsen, L. da Costa, R. Slijkhuis

In this paper the list of candidate clusters identified from the I-band data of the ESO Imaging Survey (EIS) is completed using the images obtained over a total area of about 12 square degrees. Together with the data reported earlier the total I-band coverage of EIS is 17 square degrees, which has yielded a sample of 252 cluster candidates in the redshift ra

S. Schindler, P. Belloni, Y. Ikebe, M. Hattori

Recent X-ray observations of the rich galaxy cluster CL 0939+4713 at z = 0.41 with the ROSAT/HRI as well as with the ASCA/GIS and ASCA/SIS are presented and analysed. With the high resolution imaging data we confirm and extend the earlier impression that the cluster has a lot of substructure. Two maxima of the cluster emission are obvious in the images, each

C. Benoist, L. da Costa, L. F. Olsen, E. Deul

This paper presents the I-band data obtained by the ESO Imaging Survey (EIS) over two patches of the sky, 6 square degrees each, centered at $α\sim 5^h40^m$, $δ\sim -24^\circ50^m$, and $α\sim 9^h50^m$, $δ\sim -21^\circ 00^m$. The data are being made public in the form of object catalogs and, photometrically and astrometrically calibrated pixel maps. These pr

Raka D. Ray

Making use of the possibility that gluon condensate can be formed in neutron star core, we study the vortex pinning force between the crust and the interior of the neutron star. Our estimations indicate an increase in pinning strength with the age of the neutron star. This helps in explaining observed pulsar glitches and removes some difficulties faced by vo

A. C. Goncalves, P. Veron, M. -P. Veron-Cetty

We present results based on the analysis of optical spectra of the Narrow-Line Seyfert 1 (NLS1) galaxy KUG 1031+398, for which evidence was reported of a line-emitting region &#34;intermediate&#34; (both in terms of velocity and density) between the conventional Broad and Narrow Line Regions (BLR and NLR, respectively). From our observations and modeling of

Feng Ma, Beverley J. Wills

Assuming there is a blazar type continuum in every radio-loud quasar, we find that the free-free heating due to the beamed infrared continuum can greatly enhance collisionally excited lines, and thus explain the stronger CIV $λ$1549 line emission observed in radio loud quasars. We further predict that the CIV line should show variability {\it not} associated

Feng Ma

This is a comment on a paper by Glendenning, Pei, and Weber (Phys. Rev. Lett., 79, 1603, 1997), where the authors gave an incorrect estimate of the event rate and neglected the important gravitational energy release. Previous work on the same subject is reviewed, and a new suggestion is made to link quark-hadron phase transitions with soft gamma-ray repeater

Eric Gawiser

Cosmological models predict transfer functions by which primordial density perturbations develop into CMB anisotropy and Large-Scale Structure. We use the current set of observations to reconstruct the primordial power spectrum for standard CDM, CDM with a cosmological constant, open CDM, and standard CDM with a high baryon content.

Slavek Rucinski

Cross-correlation function (CCF) has become the standard tool for extraction of radial-velocity and broadening information from high resolution spectra. It permits integration of information which is common to many spectral lines into one function which is easy to calculate, visualize and interpret. However, CCF is not the best tool for many applications whe

Joseph B. Jensen, John L. Tonry, Gerard A. Luppino

We present IR surface brightness fluctuation (SBF) distance measurements to NGC 4889 in the Coma cluster and to NGC 3309 and NGC 3311 in the Hydra cluster. We explicitly corrected for the contributions to the fluctuations from globular clusters, background galaxies, and residual background variance. We measured a distance of 85 +/- 10 Mpc to NGC 4889 and a d

Heinz Andernach

A (subjective) overview of Internet resources relevant to professional astronomers is given. Special emphasis is put on databases of astronomical objects and servers providing general information, e.g. on astronomical catalogues, finding charts from sky surveys, bibliographies, directories, browsers through multi-wavelength observational archives, etc. Archi

Helio V. Fagundes

Universes with multiconnected spatial sections predict multiple images of cosmic sources. A confusing terminology exists in the naming of these images as real ones vs. ghosts. Here an attempt is made to clarify the situation.

M. G. Moore, P. Meystre

We develop a fully quantized model of a Bose-Einstein condensate driven by a far off-resonant pump laser which interacts with a single mode of an optical ring cavity. In the linear regime, the cavity mode exhibits spontaneous exponential gain correlated with the appearance of two atomic field side-modes. These side-modes and the cavity field are generated in

Jonathan R. Friedman, M. P. Sarachik, R. Ziolo

We present the results of a detailed study of the thermally-assisted-resonant-tunneling relaxation rate of Mn12 acetate as a function of an external, longitudinal magnetic field and find that the data can be fit extremely well to a Lorentzian function. No hint of inhomogeneous broadening is found, even though some is expected from the Mn nuclear hyperfine in

B. Holdom, T. Torma

We consider a heavy fourth family with masses lying in the symmetry breaking channel of a new strong gauge interaction. This interaction generates a heavy quark axial-type operator, whose effects can be enhanced through multiple insertions. In terms of the strength of this operator we can express new negative contributions to the S and T parameters and the s

R. Ehrlich

The hypothesis that the electron neutrino is a tachyon with |m|=sqrt(-m^2) = 0.5 eV/c^2 is consistent with certain properties of the cosmic ray spectrum, including: the existence of a change in power law (the &#34;knee&#34;) at E = 10^15 eV, the E^-3 power law after the knee, another change in power law (the &#34;ankle&#34;) at E = 10^19 eV, the changes in c

O. G. Balev, P. Vasilopoulos

Based on a microscopic evaluation of the local current density, a treatment of edge magnetoplasmons (EMP) is presented for confining potentials that allow Landau level (LL) flattening to be neglected. Mode damping due to electron-phonon interaction is evaluated. For nu=1, 2 there exist independent modes spatially symmetric or antisymmetric with respect to th

A. M. Gavrilik, N. Z. Iorgov

The use, for flavor symmetries, of the quantum (or q-) analogs of unitary groups SU(n_f) yields new, very accurate, baryon mass sum rules. We show, in the 3-flavor case, that such approach accounts for nonpolynomial SU(3)-breaking effects in the octet and decuplet baryon masses. A version of this approach with manifestly q-covariant mass operator is given. T

G. Bonelli, L. Bonora, F. Nesti

The Matrix String Theory, i.e. the two dimensional U(N) SYM with N=(8,8) supersymmetry, has classical BPS solutions that interpolate between an initial and a final string configuration via a bordered Riemann surface. The Matrix String Theory amplitudes around such a classical BPS background, in the strong Yang--Mills coupling, are therefore candidates to be

M. Brack, P. Meier, K. Tanaka

We develop uniform approximations for the trace formula for non-integrable systems in which SU(2) symmetry is broken by a non-linear term of the Hamiltonian. As specific examples, we investigate Hénon-Heiles type potentials. Our formalism can also be applied to the breaking of SO(3) symmetry in a three-dimensional cavity with axially-symmetric quadrupole def

M. Schultheis, Y. K. Ng, J. Hron, F. Kerschbaum

Near-infrared photometry (JHKL&#39;M) was obtained for 78 semiregular variables (SRVs) in field #3 of the Palomar-Groningen survey (PG3, l=0, b=-10). Together with a sample of Miras in this field a comparison is made with a sample of field SRVs and Miras. The PG3 SRVs form a sequence (period-luminosity & period-colour) with the PG3 Miras, in which the SRVs a

S. Kondratyuk, O. Scholten

We present a consistent calculation of half-off-shell form factors in the pion-nucleon vertex and the nucleon self-energy. Numerical results are presented. Near the on-shell point the pion-nucleon vertex is dominated by the pseudovector coupling, while at large nucleon invariant masses we find a sizable pseudoscalar admixture.

Steven C. Erwin, Hanno H. Weitering

First-principles electronic-structure methods are used to study a structural model for Ag/Si(111)3x1 recently proposed on the basis of transmission electron diffraction data. The fully relaxed geometry for this model is far more energetically favorable than any previously proposed, partly due to the unusual formation of a Si double bond in the surface layer.

J. I. Silva-Marcos

We give a procedure to construct a special class of symmetric quark mass matrices near the democratic limit of equal Yukawa couplings for each sector. It is shown that within appropriate weak-bases, the requirements of symmetry and arg(det[M])=0 are very strong conditions, that necessarily lead to a Cabibbo angle given by |V_us|=Sqrt[md/ms], and to |V_cb|~ms

Sergei Fedotov, Sergei Mikhailov

The problem of determining the European-style option price in the incomplete market has been examined within the framework of stochastic optimization. An analytic method based on the discrete dynamic programming equation (Bellman equation) has been developed that gives the general formalism for determining the option price and the optimal trading strategy (o

Marcus Keel, Terence Tao

We prove local and global existence from large, rough initial data for a wave map between 1+1 dimensional Minkowski space and an analytic manifold. Included here is global existence for large data in the scale-invariant norm $\dot L^{1,1}$, and in the Sobolev spaces $H^s$ for $s > 3/4$. This builds on previous work in 1+1 dimensions of Pohlmeyer, Gu, Ginibre

N. Hammon, L. Gerland, H. Stöcker, W. Greiner

The extend to which geometrical effects contribute to the production and suppression of the $J/ψ$ and $q\bar{q}$ minijet pairs in general is investigated for high energy heavy ion collisions at SPS, RHIC and LHC energies. For the energy range under investigation, the geometrical effects referred to are shadowing and anti-shadowing, respectively. Due to those

M. Kawasaki, T. Yanagida

We study a double inflation model (a preinflation + a new inflation) in supergravity and discuss the formation of primordial black holes which may be identified with massive compact halo objects (MACHOs) observed in the halo of our galaxy. The preinflation drives an inflaton for the new inflation close to the origin through supergravity effects and the new i

Matthias Troyer, Subir Sachdev

Recent experiments show that double layer quantum Hall systems may have a ground state with canted antiferromagnetic order. In the experimentally accessible vicinity of a quantum critical point, the order vanishes at a temperature T_{KT} = κH, where H is the magnetic field and κis a universal number determined by the interactions and Berry phases of the ther

A. Camacho, H. Dehnen

We analyze the role that the excited states of the Higgs field could play in a possible solution to the so called localization problem of Quantum Theory. We seek a solution to the aforementioned point without introducing additional fundamental constants or extra hypotheses, as has been done in previous works. The electron and Higgs field do indeed have solit

V. Buzek, M. Hillery, R. Bednik

We show that the distribution of information at the output of the quantum cloner can be efficiently controlled via preparation of the quantum cloner. We present a universal cloning network with the help of which asymmetric cloning can be performed.

B. Hladky, G. Drobny, V. Buzek

A universal algorithm for a deterministic preparation of arbitrary three--mode bosonic states is introduced. In particular, we consider preparation of entangled quantum states of a vibrational motion of an ion confined in a 3D trapping potential. The target states are established after a proper sequence of laser stimulated Raman transitions. Stability of the

V. Faraoni, F. I. Cooperstock

The definition of mass of a scalar field in a curved space has often been generalized by grouping coupling terms between the field and the Ricci curvature with non-curvature-related mass terms. In a broader point of view, one sees that a common misunderstanding resulting from such an identification leads one, in the case of the spin 2 field, to regard the co

David B. Kaplan, Martin J. Savage, Roxanne P. Springer, Mark B. Wise

Weak interactions are expected to induce a parity violating pion-nucleon coupling, h_{πNN}^{(1)}. This coupling should be measurable in a proposed experiment to study the parity violating asymmetry A_γin the process \vec n + p \to d+γ. We compute the leading dependence of A_γon the coupling h_{πNN}^{(1)} using recently developed effective field theory techni

G. Q. Li, R. Machleidt

Based upon the Bonn meson-exchange-model for the nucleon-nucleon ($NN$) interaction, we calculate the charge-independence breaking (CIB) of the $NN$ interaction due to pion-mass splitting. Besides the one-pion-exchange (OPE), we take into account the $2π$-exchange model and contributions from three and four irreducible pion exchanges. We calculate the CIB di