March 1999 arXiv papers — page 17

Israel Quiros

The $ω\to\infty$ limit of Brans-Dicke theory is studied with the help of the conformal transformation approach without resorting, however, to the conformal invariance property of this formalism, that is shown to be spurious.

S. R. Lau

We give an explicit expression for gravitational energy, written solely in terms of physical spacetime geometry, which in suitable limits agrees with the total Arnowitt-Deser-Misner and Trautman-Bondi-Sachs energies for asymptotically flat spacetimes and with the Abbot-Deser energy for asymptotically anti-de Sitter spacetimes. Our expression is a boundary va

Harry Buhrman, Jaap-Henk Hoepman, Paul Vitanyi

We use the incompressibility method based on Kolmogorov complexity to determine the total number of bits of routing information for almost all network topologies. In most models for routing, for almost all labeled graphs $Θ(n^2)$ bits are necessary and sufficient for shortest path routing. By `almost all graphs' we mean the Kolmogorov random graphs which

W. Prellier, Amlan Biswas, M. Rajeswari, T. Venkatesan

We report the synthesis and characterization of Nd_{0.5}Sr_{0.5}MnO_{3} thin films grown by the Pulsed Laser Deposition technique on 100 -oriented LaAlO_{3} substrates. X-ray diffraction (XRD) studies show that the films are 101 -oriented, with a strained and quasi-relaxed component, the latter increasing with film thickness. We observe that transport proper

Marco Fornari, David J. Singh

The prospects for high thermoelectric performance in phosphide skutterudites are investigated based on first principles calculations. We find that stoichiometric CoP_3 differs from the corresponding arsenide and antimonide in that it is metallic. As such the band structure must be modified if high thermopowers are to be achieved. In analogy to the antimonide

S. Pilla, J. A. Hamida, K. A. Muttalib, N. S. Sullivan

We report the first audio frequency dielectric constant measurements of CO and N_2 in their solid phases. We have observed several new features, including (1) strong hysteresis effects above an onset temperature $T_{h} \simeq 42 K$ in the β-phase of pure N_2, (2) absence of the expected short range antiferroelectric dipolar ordering in CO down to 4.2 K, and

S. P. Kou, J. Q. Liang, Y. B. Zhang, F. C. Pu

In this paper we study the Macroscopic Quantum Oscillation (MQO) effect in ferromagnetic single domain magnets with a magnetic field applied along the hard anistropy axis. The level splitting for the ground state, derived with the conventional instanton method, oscillates with the external field and is quenched at some field values. A formula for quantum tun

Lev I. Deych, A. Yamilov, A. A. Lisyansky

We consider tunneling of electromagnetic waves through a polariton band gap of a 1-D chain of atoms. We analytically show that a defect embedded in the structure gives rise to the resonance transmission at the frequency of a local polariton state associated with the defect. Numerical Monte-Carlo simulations are used to examine properties of the electromagnet

Alexandre M. Zagoskin

Unique properties of a ballistic DND or grain boundary D-D junction, including doubly degenerate ground state with tunable potential barrier between the "up" and "down" states and non-quantized spontaneous magnetic flux, make it a good candidate for a solid state qubit. The role of quantum "spin" variable is played by the sign of equi

A. V. Izyumov, B. D. Simons

Using the supersymmetry approach, we study spectral statistical properties of a two-dimensional quantum particle subject to a non-uniform magnetic field. We focus mainly on the problem of regularisation of the field theory. Our analysis begins with an investigation of the spectral properties of the purely classical evolution operator. We show that, although

D. C. Brody, A. Ritz

A model in statistical mechanics, characterised by the corresponding Gibbs measure, is a subset of the totality of probability distributions on the phase space. The shape of this subset, i.e., the geometry, then plays an important role in statistical analysis of the model. It is known that this subset has the structure of a manifold equipped with a Riemannia

Yupeng Wang, Jian-Hui Dai, Fu-Cho Pu, Ulrich Eckern

We propose an integrable model of one-dimensional (1D) interacting electrons coupled with the local orbitals arrayed periodically in the chain. Since the local orbitals are introduced in a way that double occupation is forbidden, the model keeps the main feature of the periodic Anderson model with an interacting host. For the attractive interaction, it is fo

E. G. Mishchenko

The inelastic light scattering in a 2-d electron gas is studied theoretically using the Boltzmann equation techniques. Electron-hole excitations produce the Raman spectrum essentially different from the one predicted for the 3-d case. In the clean limit it has the form of a strong non-symmetric resonance due to the square root singularity at the electron-hol

Janusz Jedrzejewski, Jacek Miekisz

To our best knowledge there is only one example of a lattice system with long-range two-body interactions whose ground states have been determined exactly: the one-dimensional lattice gas with purely repulsive and strictly convex interactions. Its ground-state particle configurations do not depend on the rate of decay of the interactions and are known as the

I. Terasaki, Y. Sasago, K. Uchinokura

A transition-metal oxide NaCo_2O_4 is a layered oxide in which CoO_2 and Na alternately stack along the c axis. Recently we have found that this compound shows unusually large thermopower with low resistivity, which is comparable to those of Bi_2Te_3. The negative transverse magnetoresistance and the strongly temperature-dependent Hall coefficient suggest th

J. Hooyberghs, C. Vanderzande

The stationary state of stochastic processes such as reaction-diffusion systems can be related to the ground state of a suitably defined quantum Hamiltonian. Using this analogy, we investigate the applicability of a real space renormalisation group approach, originally developped for quantum spin systems, to interacting particle systems. We apply the techniq

W. Pan, R. R. Du, H. L. Stormer, D. C. Tsui

We have investigated the influence of an increasing in-plane magnetic field on the states at half-filling of Landau levels ($ν$ = 11/2, 9/2, 7/2, and 5/2) of a two-dimensional electron system. In the electrically anisotropic phase at $ν$ = 9/2 and 11/2 an in-plane magnetic field of $\sim$ 1-2 T overcomes its initial pinning to the crystal lattice and {\it re

Sul-Ah Ahn, Kwangyl Park, Sung-Ho Suck Salk

We present functional Schrödinger representations of Holstein-Primakoff boson and slave-boson theories for the Heisenberg Hamiltonian and the $t-J$ Hamiltonian respectively. Based on these representations we obtain the dispersion relations of magnons for two dimensional antiferromagnets. By applying the functional Schrödinger representation of the Holstein-P

Ruslan L. Davidchack, Brian. B. Laird

In order to construct a general density-functional theory for nonuniform fluid mixtures, we propose an extension to multicomponent systems of the weighted-density approximation (WDA) of Curtin and Ashcroft [Phys. Rev. A 32, 2909 (1985)]. This extension corrects a deficiency in a similar extension proposed earlier by Denton and Ashcroft [Phys. Rev. A 42, 7312

Ruslan L. Davidchack, Brian. B. Laird

We examine, using molecular dynamics simulation, the structure and thermodynamics of the (100) and (111) disordered face-centered cubic (FCC) crystal/melt interfaces for a binary hard-sphere system. This study is an extension of our previous work, [Phys. Rev. E 54, R5905 (1996)], in which preliminary data for the (100) interface were reported. Density and di

X. Jehl, P. Payet-Burin, C. Baraduc, R. Calemczuk

We present a resistance bridge which uses a SQUID to measure the shot noise in low impedance samples. The experimental requirements are high DC bias currents (typically 10mA) together with high AC sensitivity (pA/VHz). This system is used to investigate the shot noise in Superconductor/Normal/Superconductor junctions where Andreev reflection enhanced shot no

Juan L. Cabrera, J. Gorro~nogoitia, F. J. de la Rubia

We investigate the behavior of the residence times density function for different nonlinear dynamical systems with limit cycle behavior and perturbed parametrically with a colored noise. We present evidence that underlying the stochastic resonancelike behavior with the noise correlation time, there is an effect of optimal localization of the system trajector

John W. Bieber, R. A. Burger, Ralph Engel, Thomas K. Gaisser

New measurements with good statistics will make it possible to observe the time variation of cosmic antiprotons at 1 AU through the approaching peak of solar activity. We report a new computation of the interstellar antiproton spectrum expected from collisions between cosmic protons and the interstellar gas. This spectrum is then used as input to a steady-st

Paolo S. Coppi

I present a general overview of the results discussed during the Cracow 1997 workshop on ``Relativistic Jets in AGNs.'' My emphasis will be on showing the significant progress made in several areas over the last few years, pointing out what I feel are some of the more important issues still facing us today, and suggesting where progress is likely to

Paolo S. Coppi Felix A. Aharonian

With the arrival of powerful, ground-based gamma-ray detectors, we can now begin to seriously probe, via simultaneous X-ray/TeV observations, the origin of the gamma-ray emission in the blazars Mrk 421 and 501. If the synchrotron-Compton emission model turns out to work, then we know that the same electrons are responsible for both the X-ray and the gamma-ra

Paolo S. Coppi

Models of the continuum radiation from accreting hot plasmas typically assume that the plasma heating mechanism produces energetic particles distributed in energy either as a Maxwellian (the ``thermal'' models) or as an extended power law (the ``non-thermal'' models). The reality, however, is that neither description is probably accurate. In

Simon Lilly, Stephen Eales, Walter Gear, Tracy Webb

Deep surveys of the sky at millimeter wavelengths have revealed a population of ultra-luminous infrared galaxies (ULIRGs) at high redshifts. These appear similar to local objects of similar luminosities (such as Arp220) but are much more ``important'' at high redshift than at low reshift, in the sense that they represent a much larger fraction of the

R. Fux

The gas dynamics in the Galactic disc is modeled by releasing an initially axisymmetric SPH component in a completely self-consistent and symmetry-free 3D N-body simulation of the Milky Way in which the stellar components display a COBE-like bar. The density centre of the stellar bar wanders around the centre of mass and the resulting gas flow is asymmetric

A. M. Beloborodov, J. Poutanen

Optical/UV radiation from accretion disks in quasars is likely to be partly scattered by a hot plasma enveloping the disk. We investigate whether the scattering may produce the steep rises in polarization observed blueward of the Lyman limit in some quasars. We suggest and assess two models. In the first model, primary disk radiation with a Lyman edge in abs

D. Lutz, S. Veilleux, R. Genzel

New tools from Infrared Space Observatory (ISO) mid-infrared spectroscopy have recently become available to determine the power sources of dust-obscured ultraluminous infrared galaxies (ULIRGs). We compare ISO classifications - starburst or active galactic nucleus (AGN) - with classifications from optical spectroscopy, and with optical/near-infrared searches

Martijn de Kool, Dayal T. Wickramasinghe

We investigate the thermal stability of the outer layers of accretion discs in which the local viscous energy dissipation rate scales with the pressure as for standard Shakura-Sunyaev discs. By solving for the accretion disc vertical structure using the grey two-stream approximation, we show that the thermal structure of the optically thin outer layers is in

Mercedes Molla, Angeles Diaz, Federico Ferrini

The distribution of element abundances with redshift in Damped Ly-alpha (DLA) systems can be adequately reproduced by the same model reproducing the halo and disk components of the Milky Way Galaxy at different galactocentric distances: DLA systems are well represented by normal spiral galaxies in their early evolutionary stages.

L. Cambresy

This paper presents large scale extinction maps of most nearby Giant Molecular Clouds of the Galaxy (Lupus, rho-Ophiuchus, Scorpius, Coalsack, Taurus, Chamaeleon, Musca, Corona Australis, Serpens, IC 5146, Vela, Orion, Monoceros R1 and R2, Rosette, Carina) derived from a star count method using an adaptive grid and a wavelet decomposition applied to the opti

Jeroen Homan, Peter G. Jonker, Rudy Wijnands, Michiel van der Klis

We report the discovery of a quasi-periodic oscillation (QPO) in data obtained with the Rossi X-ray Timing Explorer of the dipping and eclipsing low-mass X-ray binary EXO 0748-676. The QPO had a frequency between 0.58 and 2.44 Hz changing on time scales of a few days, an rms amplitude between 8% and 12%, and was detected in the persistent emission, during di

H. Krüger, E. Grün, A. Heck, S. Lammers

The Dust Detector System onboard Galileo records dust impacts in the Jupiter system. Impact events are classified into four quality classes. Class 3 -- our highest quality class -- has always been noise-free and, therefore, contains only true dust impacts. Depending on the noise environment, class 2 are dust impacts or noise. Within $20 R_J$ from Jupiter (Ju

Mercedes Molla, Jean-Rene Roy

We show that the multiphase chemical evolution model reproduces the correlations obtained along the spiral sequence, dwarf galaxies included. However the apparent spatial chemical uniformity observed in some irregular galaxies cannot be reproduced with it. An evolutionary model has been developed and tested to explain flat gradients. Preliminary results, obt

D. Friedli

The life of disk galaxies is likely punctuated with the birth (spontaneous or induced), the aging (quick or slow), and the death (sudden or progressive) of bars. These events are responsible for various major changes of the galaxy which occur both on dynamical ($\sim$0.1 Gyr) and cosmological ($\sim$10 Gyr) time-scales, as well as both on large- ($\ga$10 kpc

A. J. Barger, L. L. Cowie, I. Smail, R. J. Ivison

We present a Keck II LRIS spectroscopic follow-up study of the possible optical counterparts to a flux-limited sample of galaxies selected from an 850-micron survey of massive lensing clusters using the SCUBA bolometer array on the JCMT. These sources represent a population of luminous dusty galaxies responsible for the bulk of the 850-micron background dete

Greg M. Madejski

This paper summarizes the observations which provide the best evidence for the presence of black holes in active galactic nuclei. This includes: X-ray variability; kinematical studies using optical emission lines as well as the distribution of megamaser spots; and the shape of the Fe K$α$ X-ray emission line. It also presents the current status of our unders

A. V. Kopylov

The comparison of magnetic moment of neutron and proton enables to outline qualitatively the structure of nucleon by using a model similar to the one suggested by Ida and Kobayashi that "baryons consist of a qq pair (or a diquark) and another quark moving around it with orbital angular momentum L".

Abhas Mitra

We exploit the fact that General Theory of Relativity (GTR) predicts the existence of compact objects having surface gravitational redshift z_s < =z_c=0.615 when the Equation of State (EOS) has the stringest general constraint that the speed of sound c_s < = 0.57 c. This z_c can be occur if a Neutron Star (NS) has a mass of ~2 M (solar) and radius ~8 Km, as

M. Stephanov, K. Rajagopal, E. Shuryak

The event-by-event fluctuations of suitably chosen observables in heavy ion collisions at SPS, RHIC and LHC can tell us about the thermodynamic properties of the hadronic system at freeze-out. By studying these fluctuations as a function of varying control parameters, it is possible to learn much about the phase diagram of QCD. As a timely example, we stress

Valeri N. Kotov, J. Oitmaa, Oleg P. Sushkov, Zheng Weihong

We analyze the stability of the spontaneously dimerized spin-liquid phase of the frustrated Heisenberg antiferromagnet - the J1-J2 model. The lowest triplet excitation, corresponding to breaking of a singlet bond, is found to be stable in the region 0.38 < J2/J1 < 0.62. In addition we find a stable low-energy collective singlet mode, which is closely related

G. I. Gomero, M. J. Reboucas, A. F. F. Teixeira, A. Bernui

We study the role played by multiply-connectedness in the time evolution of the energy E(t) of a radiating system that lies in static flat space-time manifolds M_4 whose t=const spacelike sections M_3 are compact in at least one spatial direction. The radiation reaction equation of the radiating source is derived for the case where M_3 has any non-trivial fl

Paolo Tozzi, Piero Madau, Avery Meiksin, Martin J. Rees

The emission of 21-cm radiation from a neutral intergalactic medium (IGM) at high redshift is discussed in connection with the thermal and ionization history of the universe. The physical mechanisms that make such radiation detectable against the cosmic microwave background include Ly_alpha coupling of the hydrogen spin temperature to the kinetic temperature

J. L. Diaz-Cruz, M. A. Perez, G. Tavares-Velasco, J . J. Toscano

We discuss the Flavor-Changing Neutral Current (FCNC) decays of the top quark t -> c Vi Vj (Vi=gamma, Z, g) in the framework of the Standard Model (SM) and in a two-higgs doublet model (2HDM) with tree-level FCNC couplings. While in the SM the expected branching ratios are extremelly small, in the 2HDM they may be sizable, of order 10^(-5) - 10^(-5), and thu

Marco M. Caldarelli, Dietmar Klemm

We consider black holes in anti-de Sitter space AdS_{p+2} (p = 2,3,5), which have hyperbolic, flat or spherical event horizons. The $O(α&#39;^3)$ corrections (or the leading corrections in powers of the eleven-dimensional Planck length) to the black hole metrics are computed for the various topologies and dimensions. We investigate the consequences of the st

F. Grundahl, M. Catelan, W. B. Landsman, P. B. Stetson

A &#34;jump&#34; in the BHB distribution in the V, u-y CMD was recently detected in the GC M13. It is morphologically best characterized as a discontinuity in u, u-y, with stars in the range 11,500<Teff(K)<20,000 deviating systematically from (in the sense of appearing brighter and/or hotter than) canonical ZAHBs. We present u, y photometry of 14 GCs obtaine

Luis P. Chimento, Alejandro S. Jakubi, Diego Pavon

In this paper the second Lyapunov method is used to study the stability of the de Sitter phase of cosmic expansion when the source of the gravitational field is a viscous fluid. Different inflationary scenarios related with reheating and decay of mini-blackholes into radiation are investigated using an effective fluid described by time--varying thermodynamic

M. Effenberger, E. L. Bratkovskaya, U. Mosel

We present a calculation of e^+e^- production in $γA$ reactions at MAMI and TJNAF energies within a semi-classical BUU transport model. Dilepton invariant mass spectra for $γ$C, $γ$Ca and $γ$Pb are calculated at 0.8, 1.5 and 2.2 GeV. We focus on observable effects of medium modifications of the $ρ$ and $ω$ mesons. The in-medium widths of these mesons are tak

Y. C. Huang, Xi-Guo Lee, Ming-Xue Shao

In terms of the quantitative causal principle, this paper obtains a general variational principle, gives unified expressions of the general, Hamilton, Voss, Hölder, Maupertuis-Lagrange variational principles of integral style, the invariant quantities of the general, Voss, Hölder, Maupertuis-Lagrange variational principles are given, finally the Noether cons

Arkadiusz Wojs, John J. Quinn

The mean field composite Fermion (CF) picture successfully predicts angular momenta of multiplets forming the lowest energy band in fractional quantum Hall (FQH) systems. This success cannot be attributed to a cancellation between Coulomb and Chern-Simons interactions beyond the mean field, because these interactions have totally different energy scales. Rat

C. P. Martin, D. Sanchez-Ruiz

We show that U(1) Yang-Mills theory on noncommutative R^4 can be renormalized at the one-loop level by multiplicative dimensional renormalization of the coupling constant and fields of the theory. We compute the beta function of the theory and conclude that the theory is asymptotically free. We also show that the Weyl-Moyal matrix defining the deformed produ

KTeV Collaboration

The branching ratio of the rare decay pi^0 -> e^+e^- has been measured in E799-II, a rare kaon decay experiment using the KTeV detector at Fermilab. The pi^0&#39;s were produced in fully-reconstructed K_L -> 3 pi^0 decays in flight. We observed 275 candidate pi^0 -> e^+e^- events, with an expected background of 21.4 +- 6.2 events which includes the contribut

R. D. Pisarski, D. H. Rischke

We study superfluidity in a model of massless fermions coupled to a massive scalar field through a Yukawa interaction. Gap equations for a condensate with total spin J=0 are solved in the mean-field approximation. For the Yukawa interaction, the gaps for right- and left-handed fermions are equal in magnitude and opposite in sign, so that condensation occurs

D. Bruss, L. Faoro, C. Macchiavello, M. Palma

We analyse the role of entanglement for transmission of classical information through a memoryless depolarising channel. Using the isotropic character of this channel we prove analytically that the mutual information cannot be increased by encoding classical bits into entangled states of two qubits.

A. Y. Potekhin, D. A. Baiko, P. Haensel, D. G. Yakovlev

New calculations of the thermal and electrical electron conductivities are performed for a broad range of physical parameters typical for envelopes of neutron stars and cores of white dwarfs. We consider stellar matter composed of astrophysically important chemical elements from H to Fe in the density range from 10^2-10^4 g/ccm up to 10^7-10^{10} g/ccm, wher

G. Mussardo, P. Simon

We consider the simplest bosonic-type S-matrix which is usually regarded as unphysical due to the complex values of the finite volume ground state energy. While a standard quantum field theory interpretation of such a scattering theory is precluded, we argue that the physical situation described by this S-matrix is of a massive Ising model perturbed by a par

Kingman Cheung, Wai-yee Keung

Gravity can become strong at the TeV scale in the theory of extra dimensions. An effective Lagrangian can be used to describe the gravitational interactions below a cut-off scale. In this work, we study the associated production of the gravitons with a $Z$ boson or a photon at $e^+ e^-$ colliders of energies of LEPII to the Next Linear Colliders (NLC) ($\sqr

S. Arunagiri

Using the relation between the harmonic oscillator wave function and the light quark scattering form factor, the expectation values of colour-straight four-quark operators are evaluated and found to be directly proportional to the cubic power of the oscillator strength. It is predicted that the ratio τ(Λ_b)/τ(B) \approx 0.79(0.84) due to the factorizable (no

Y. C. Chen, A. H. Castro Neto

We propose an effective two-dimensional quantum non-linear sigma model combined with classical percolation theory to study the magnetic properties of site diluted layered quantum antiferromagnets like La$_{2}$Cu$_{1-x}$M$_x$O$_{4}$ (M$=$Zn, Mg). We calculate the staggered magnetization at zero temperature, $M_s(x)$, the magnetic correlation length, $ξ(x,T)$,

Almut Beige, Gerhard C. Hegerfeldt

If an atom is able to exhibit macroscopic dark periods, or electron shelving, then a driven system of two atoms has three types of fluorescence periods (dark, single and double intensity). We propose to use the average durations of these fluorescence types as a simple and easily accessible indicator of cooperative effects. As an example we study two dipole-i

M. Dineykhan, R. G. Nazmitdinov

The oscillator representation method is presented and used to calculate the energy spectra for a superposition of Coulomb and power-law potentials and for Coulomb and Yukawa potentials. The method provides an efficient way to obtain analytic results for arbitrary values of the parameters specifying the above-type potentials. The calculated energies of the gr

Yoel Tikochinsky

A carefully written paper by A. Caticha [Phys. Rev. A57, 1572 (1998)] applies consistency arguments to derive the quantum mechanical rules for compounding probability amplitudes in much the same way as earlier work by the present author [J. Math. Phys. 29, 398 (1988) and Int. J. Theor. Phys. 27, 543 (1998)]. These works are examined together to find the mini

A. C. Doherty, S. M. Tan, A. S. Parkins, D. F. Walls

The possibility of determining the state of a quantum system after a continuous measurement of position is discussed in the framework of quantum trajectory theory. Initial lack of knowledge of the system and external noises are accounted for by considering the evolution of conditioned density matrices under a stochastic master equation. It is shown that afte

J. C. Pupin, M. R. Robilotta

The leading contribution to the three-pion exchange nucleon-nucleon potential is calculated in the framework of chiral symmetry. It has pseudoscalar and axial components and is dominated by the former, which has a range of about 1.5 fm and tends to enhance the OPEP. The strength of this force does not depend on the pion mass and hence it survives in the chir

S. E. Massen, H. C. Moustakidis

Analytical expressions of the one- and two-body terms in the cluster expansion of the charge form factors and densities of the s-p and s-d shell nuclei with N=Z are derived. They depend on the harmonic oscillator parameter b and the parameter $β$ which originates from the Jastrow correlation function. These expressions are used for the systematic study of th

Takashi Nakatsukasa, Niels R. Walet, Giu Do Dang

We investigate the RPA normal-mode coordinates in the pairing-plus-quadrupole model, with an eye on simplifying the application of large amplitude collective motion techniques. At the Hartree-Bogoliubov minimum, the RPA modes are exactly the cranking operators of the collective coordinate approach. We examine the possibility of representing the self-consiste

E. Kolbe, K. Langanke, P. Vogel

We extend our previous studies of the neutrino-induced reactions on 12C and muon capture to include partial occupation of nuclear subshells in the framework of the continuum random phase approximation. We find, in contrast to the work by Auerbach et al., that a partial occupation of the p1/2 subshell reduces the inclusive cross sections only slightly. The ex

A. Ohnishi, Y. Hirata, Y. Nara, S. Shinmura

We analyze the invariant mass spectrum of Lambda-Lambda in $^{12}C(K^-,K^+ Lambda Lambda)$ reaction at P(K^+)=1.65 GeV/c by using a combined framework of IntraNuclear Cascade (INC) model and the correlation function technique. The observed enhancement at low-invariant masses can be well reproduced with attractive Lambda-Lambda interactions with the scatterin

F. Hibou, O. Bing, M. Boivin, P. Courtat

The total cross section for omega production in the pp -> pp omega reaction has been measured at five c.m. excess energies from 3.8 to 30 MeV. The energy dependence is easily understood in terms of a strong proton-proton final state interaction combined with a smearing over the width of the state. The ratio of near-threshold phi and omega production is consi

O. A. Chalykh, M. V. Feigin, A. P. Veselov

A notion of rational Baker-Akhiezer (BA) function related to a configuration of hyperplanes in C^n is introduced. It is proved that BA function exists only for very special configurations (locus configurations), which satisfy certain overdetermined algebraic system. The BA functions satisfy some algebraically integrable Schrodinger equations, so any locus co

E. A. Kochetov, V. A. Osipov

A variant of a gauge theory is formulated to describe disclinations on Riemannian surfaces that may change both the Gaussian (intrinsic) and mean (extrinsic) curvatures, which implies that both internal strains and a location of the surface in R^3 may vary. Besides, originally distributed disclinations are taken into account. For the flat surface, an extende

Stefan Waldmann

In the framework of deformation quantization we apply the formal GNS construction to find representations of the deformed algebras in pre-Hilbert spaces over $\mathbb C[[λ]]$ and establish the notion of local operators in these pre-Hilbert spaces. The commutant within the local operators is used to distinguish `thermal&#39; from `pure&#39; representations. T

Anton Alekseev, Eckhard Meinrenken

Let G be a connected Lie group with Lie algebra g. The Duflo map is a vector space isomorphism between the symmetric algebra S(g) and the universal enveloping algebra U(g) which, as proved by Duflo, restricts to a ring isomorphism from invariant polynomials onto the center of the universal enveloping algebra. The Duflo map extends to a linear map from compac

Charles Frohman, Joanna Kania-Bartoszynska

We use topological quantum field theory to derive an invariant of a three-manifold with boundary. We then show how to use this invariant as an obstruction to embedding one three-manifold in another.

Kevin Keating

Let T be a tile in the Cartesian plane made up of finitely many rectangles whose corners have rational coordinates and whose sides are parallel to the coordinate axes. This paper gives necessary and sufficient conditions for a square to be tilable by finitely many \Q-weighted tiles with the same shape as T, and necessary and sufficient conditions for a squar

A. T. Suzuki, A. G. M. Schmidt

Negative dimensional integration method (NDIM) is revealing itself as a very useful technique for computing Feynman integrals, massless and/or massive, covariant and non-covariant alike. Up to now, however, the illustrative calculations done using such method are mostly covariant scalar integrals, without numerator factors. Here we show how those integrals w

Takao Koikawa

We formulate the soliton equations on the lattice in terms of the reduced Moyal algebra which includes one parameter. The vanishing limit of the parameter leads to the continuous soliton equations.

A. Kuiroukidis, D. B. Papadopoulos, J. E. Paschalis

We study the evolution, the transverse spreading and the subsequent thermalization of string states in the Weyl static axisymmetric spacetime. This possesses a singular event horizon on the symmetry axis and a naked singularity along the other directions. The branching diffusion process of string bits approaching the singular event horizon provides the notio

D. V. Shirkov

This text follows the line of a talk on Ringberg symposium dedicated to Wolfhart Zimmermann 70th birthday. The historical overview (Part 1) partially overlaps with corresponding text of my previous commemorative paper. At the same time second part includes some recent results in QFT and summarize an impressive progress of the &#34;QFT renormalization group&#

Jouko Mickelsson

The current algebra generated by fermions coupled to external gauge potentials and metrics on a manifold with boundary is discussed. It is shown that the previous methods, based on index theory arguments and used in the case without boundaries, carry over to the present problem. The resulting current algebra is the same as obtained from a quantization of bos

Soo-Young Lee, Hungsoo Kim, D. K. Park, Jae Kwan Kim

We investigate a relationship between the number of the negative modes around periodic instanton solution and the type of the decay-rate transition. It is shown that for the case of first-order decay-rate transition the lowest positive mode at low energy periodic instanton becomes additional negative mode at high energy regime, while in the second-order case

Mu-In Park, Young-Jai Park

Recently proposed new gauge invariant formulation of the Chern-Simons gauge theory is considered in detail. This formulation is consistent with the gauge fixed formulation. Furthermore it is found that the canonical (Noether) Poincaré generators are not gauge invariant even on the constraints surface and do not satisfy the Poincaré algebra contrast to usual

E. D&#39;Hoker, D. H. Phong

We summarize recent results on the resolution of two intimately related problems, one physical, the other mathematical. The first deals with the resolution of the non-perturbative low energy dynamics of certain N=2 supersymmetric Yang-Mills theories. We concentrate on the theories with one massive hypermultiplet in the adjoint representation of an arbitrary

R. Parthasarathy

The finite gauge transformation, in the submanifold of su(3) introduced in hep-th/9902027, is found to be linear in the gauge functions $ω^a$&#39;s. In this manner, a parameterization of SU(3) in terms of a single real octet vector $ω^a$ is achieved. Under this finite transformation, those gauge fields satisfying $D^{ab}_μω^b = 0$, remain unchanged. A geomet

Marco Laucelli Meana, Jesús Puente Peñalba

We study the microcanonical description of string gases in the presence of D-branes. We obtain exact expressions for the single string density of states and draw the regions in phase space where asymptotic approximations are valid. We are able to describe the whole range of energies including the SYM phase of the D-branes and we remark the importance of the

Steven S. Gubser

We derive a solution of type IIB supergravity which is asymptotic to AdS_5 x S^5, has SO(6) symmetry, and exhibits some of the features expected of geometries dual to confining gauge theories. At the linearized level, the solution differs from pure AdS_5 x S^5 only by a dilaton profile. It has a naked singularity in the interior. Wilson loops follow area law

E. Kh. Akhmedov

Neutrino oscillations in matter can exhibit a specific resonance enhancement -- parametric resonance, which is different from the MSW resonance. Recently it has been shown that the oscillations of atmospheric and solar neutrinos inside the earth can undergo parametric enhancement when neutrino trajectories cross the core of the earth. In this paper we contin

P. Osland

When Higgs boson candidates will be found at future colliders, it becomes imperative to determine their properties, beyond the mass, production cross section and decay rates. Other crucial properties are those related to the behaviour under CP transformations, and the self-couplings. This paper addresses the question of measurability of some of the trilinear

S. Carlier, J. -M. Frère, F. -S. Ling

In this paper, we examine how gauge interactions can dilute the lepton asymmetry in lepton induced baryogenesis. Constraints imposed on Majorana masses keep this dilution at an acceptable level.

Pran Nath, Masahiro Yamaguchi

An analysis of the effects associated with the Kaluza-Klein excitations of the photon and of the W and Z bosons on g_μ-2 for d number of extra dimensions with large radius compactifications is given. The Kaluza-Klein effects on g_μ-2 are found to be very sensitive to the number of extra dimensions. For models where the quark-lepton generations live on the 4D

E. V. Shuryak

Because too many interesting things are going on now, I have tried to squeeze three different subjects into one talk. The first is a brief summary of the color super-conductivity. During the last year we learned that instanton-induced forces can not only break chiral symmetry in the QCD vacuum, but also create correlated scalar diquarks and form new phases,s

H. J. Drescher, M. Hladik, S. Ostapchenko, K. Werner

It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, we construct a model for all these interactions, which relies on the fundamental hypothesis that the beha

Dirk Graudenz

I review the status of next-to-leading-order calculations for hadronic final states in deeply-inelastic lepton--nucleon scattering. In more detail, I focus on calculations of (2+1)-jet-type cross sections, describe recent progress in extending the perturbative description into the transition region between deeply inelastic scattering and photoproduction, and

J. Raufeisen, A. V. Tarasov, O. O. Voskresenskaya

In the rest frame of the nucleus, shadowing is due to hadronic fluctuations of the incoming virtual photon, which interact with the nucleons. We expand these fluctuations in a basis of eigenstates of interaction and take only the $q\bar q$ component of the hadronic structure of the photon into account. We use a representation in which the $q\bar q$-pair has

O. Biebel, P. A. Movilla Fernández, S. Bethke, the JADE Collaboration

e^+e^- annihilation data recorded by the JADE detector at PETRA were used to measure the C-parameter for the first time at \sqrt{s}= 35 and 44 GeV. The distributions were compared to a resummed QCD calculation. In addition, we applied extended resummed calculations to the total and wide jet broadening variables, B_T and B_W. We combined the results on α_s wi

C. Adloff

The electroproduction of J/psi and psi(2S) mesons is studied in elastic, quasi-elastic and inclusive reactions for four momentum transfers 2 < Q^2 < 80 GeV^2 and photon-proton centre of mass energies 25 < W < 180 GeV. The data were taken with the H1 detector at the electron proton collider HERA in the years 1995 to 1997. The total virtual photon-proton cross

Kamiokade Collaboration, Y. Takeuchi et al

Radioactivity from radon is a major background for observing solar neutrinos at Super-Kamiokande. In this paper, we describe the measurement of radon concentrations at Super-Kamiokande, the method of radon reduction, and the radon monitoring system. The measurement shows that the current low-energy event rate between 5.0 MeV and 6.5 MeV implies a radon conce

N. Arnaud, F. Cavalier, M. Davier, P. Hello

We present several filtering methods which can be used as triggers for the detection of gravitational wave bursts in interferometric detectors. All the methods are compared to matched filtering with the help of a figure of merit based on the detection of supernovae signals simulated by Zwerger and Muller.