September 1999 arXiv papers — page 24

Giovanni Gallavotti, Fabio Perroni

An experimental test of a large fluctuation theorem is performed on a chain of coupled ``cat maps''. Our interest is focused on the behavior of a subsystem of this chain. A local entropy creation rate is defined and we show that the local fluctuation theorem derived in [G1] is experimentally observable already for small subsystems.

J. E. Larkin, T. M. Glassman

This paper presents a new strategy for observing faint galaxies with high order natural guide star systems. We have imaged 5 high galactic latitude fields within the isoplanatic patch of bright stars (8.5 < R < 10.3 mag). The fields provide a rich set of faint field galaxies that are observable with a natural guide star adaptive optics system on a large tele

Alejandro Clocchiatti, Mark M. Phillips, Nicholas B. Suntzeff, Massimo DellaValle

We present spectroscopic and photometric observations of SN1992ar, the more distant SN in the Calan/Tololo Survey. We compare its spectrum with those of nearby Type Ia and Ic SNe and conclude that the latter type is a better match to SN 1992ar. Using K-corrections based on the spectra of well observed Type Ic and Ia SNe we compute different possible rest fra

D. M. Goldberg, D. N. Spergel

In this report, we present a new method for reconstructing N body initial conditions from a proscribed final density field. This method, Perturbative Least Action (PLA) is similar to traditional least action approaches, except that orbits of particles are found as expansions around previously determined and physically motivated orbits.

L. Verdes-Montenegro, M. S. Yun, B. A. Williams, W. K. Huchtmeier

We present a global study of HI spectral line mapping for 16 Hickson Compact Groups (HCGs) combining new and unpublished VLA data, plus the analysis of the HI content of individual galaxies. Sixty percent of the groups show morphological and kinematical signs of perturbations (from multiple tidal features to concentration of the HI in a single enveloping clo

Oliver Czoske, Genevieve Soucail, Jean-Paul Kneib, Terry Bridges

We present a detailed velocity histogram from a wide-field spectroscopic survey in the field of the cluster lens Cl0024 showing an unrelaxed foreground structure in addition to the relaxed main cluster. This finding reduces the velocity dispersion of the main cluster compared to previous studies by a factor of about 2 and thus resolves the discrepancy betwee

T. Cline, D. D. Frederiks, S. Golenetskii, K. Hurley

We report on two observations of a soft bursting source in 1997 June, whose time histories and energy spectra are consistent with those of the soft gamma repeaters. The source can only be localized to an ~3.8 degree long error box in the direction of the Galactic center, whose area is ~ 80 sq. arcmin. The location of the source, while not consistent with tha

G. A. Kriss, A. F. Davidsen, W. Zheng, G. Lee

We present absolutely calibrated FUV spectra of the quasar 3C~273 covering 900- 1800 A. Our ~3 A resolution spectra were obtained with the Hopkins Ultraviolet Telescope during the Astro-1 mission in December 1990 and during the Astro-2 mission in March 1995. Both spectra exhibit a change in slope near the Lyman limit in the quasar rest frame. At longer UV wa

M. Hanauske, D. Zschiesche, S. Pal, S. Schramm

We investigate various properties of neutron star matter within an effective chiral $SU(3)_L \times SU(3)_R$ model. The predictions of this model are compared with a Walecka-type model. It is demonstrated that the importance of hyperon degrees are strongly depending on the interaction used, even if the equation of state near saturation density is nearly the

D. L. Khokhlov

The fractal structure with a power index of 2 is considered within the framework of the universe with the linear law of evolution. The fractal structure arises due to the linear evolution of the scale of mass. Potential fluctuations connect two scales and thus define the preferred scales. The hierarchy of the preferred scales is developed which includes univ

R. Asiain, F. Figueras, J. Torra

The disruption of stellar systems, such as open clusters or stellar complexes, stands out as one of the most reasonable physical processes accounting for the young moving groups observed in the solar neighbourhood. In the present study we analyse some of the mechanisms that are important in the kinematic evolution of a group of unbound stars, such as the foc

M. R. Burleigh, R. A. Saffer, G. F. Gilmore, R. Napiwotzki

An optical spectrum of the Elson et al. (1998) candidate luminous white dwarf in the young LMC cluster NGC1818 shows conclusively that it is not a degenerate star. A model atmosphere fit gives T=31,500K and log g=4.4, typical of a garden-variety main sequence B star. However, if it is a true LMC member then the star is under-luminous by almost three magnitud

Kee-Tae Kim, Bon-Chul Koo

We have carried out high-resolution (~3&#39;) HI and CO line observations of GW46.4+5.5 and analyzed available IR and radio emission survey data. GW46.4+5.5 appears as a long filamentary structure extending vertically from the Galactic plane in both far-IR and radio continuum maps. The I_60/I_100 ratio in the worm is estimated to be 0.29+-0.05, which is sign

Ignasi Ribas, Edward F. Guinan, Edward L. Fitzpatrick, Laurence E. DeWarf

We are carrying out an international, multi-wavelength program to determine the fundamental properties and independent distance estimates of selected eclipsing binaries in the LMC and SMC. Eclipsing binaries with well-defined double-line radial velocity curves and light curves provide valuable information on orbital and physical properties of their component

D. L. Clements

We apply both a traditional `dropout&#39; approach and a photometric redshift estimation technique to the Hubble Deep Field South data. We give a list of dropout selected z$\sim$3 objects, and show their images. We then discuss our photometric redshift estimation technique, demonstrate both its effectiveness and the role played by near-IR data, and then appl

Ian R. Stevens, David K. Strickland, Karen A. Wills

We investigate the X-ray emission from the central regions of the prototypical starburst galaxy M82. Previous observations had shown a bright central X-ray point source, with suggestions as to its nature including a low-luminosity AGN or an X-ray binary. A new analysis of ROSAT HRI observations find 4 X-ray point sources in the central kpc of M82 and we iden

K. Beuermann, F. V. Hessman, K. Reinsch, H. Nicklas

We present BVRI photometry and spectrophotometry of GRB990510 obtained with the ESO VLT/Antu telescope during the late decline phase. Between days 8 and 29 after the burst, the afterglow faded from R=24.2 to ~26.4. The spectral flux distribution and the light curve support the interpretation of the afterglow as synchrotron emission from a jet. The light curv

Sabine Schindler

Clusters of galaxies are large gravitationally bound systems which consist of several observable components: hundreds of galaxies, hot gas between the galaxies and sometimes relativistic particles. These components are emitting in different wavelengths from radio to X-rays. We show that the combination of observations at different frequencies and also theore

F. Favata, J. H. M. M. Schmitt

We present an X-ray observation of the eclipsing binary Algol, obtained with the BeppoSAX observatory. During the observation a huge flare was observed, exceptional both in duration as well as in peak plasma temperature and total energy release. The wide spectral response of the different BeppoSAX instruments, together with the long decay time scale of the f

J. H. M. M. Schmitt, F. Favata

Giant flares can release large amounts of energy within a few days: X-ray emission alone can be up to ten percent of the star&#39;s bolometric luminosity. These flares exceed the luminosities of the largest solar flares by many orders of magnitude, which suggests that the underlying physical mechanisms supplying the energy are different from those on the Sun

A. N. Parmar, T. Oosterbroek, D. Dal Fiume, M. Orlandini

Results of a 1999 July 8-10 BeppoSAX observation during an anomalous low-state of Her X-1 are presented. The standard on-state power-law and blackbody continuum model is excluded at high confidence unless partial covering is included. This gives a power-law photon index of 0.63 +/- 0.02 and implies that 0.28 +/- 0.03 of the flux undergoes additional absorpti

John P. Ralston, Pankaj Jain, George M. Frichter

We report on the feasibility of using an isotropic flux of cosmic neutrinos in the energy range of 10 to 10,000 TeV to study the interior geophysical structure of the Earth. The angular distribution of events in a $\sim {\rm km}^3$-scale neutrino telescope can be inverted to yield the Earth&#39;s nucleon density distribution. The approach is independent of p

John S. Carr, K. Sellgren, Suchitra C. Balachandran

The first measurement of the photospheric abundances in a star at the Galactic Center are presented. A detailed abundance analysis of the Galactic Center M2 supergiant IRS 7 was carried out using high-resolution near-infrared echelle spectra. The Fe abundance for IRS 7 was found to be close to solar, [Fe/H] = -0.02 +/- 0.13, and nearly identical to the Fe ab

J. Bezecourt, G. Soucail, R. S. Ellis, J. -P. Kneib

We discuss the statistical properties of faint background galaxies detected in a deep Hubble Space Telescope ultraviolet (F336W) Wide Field Planetary Camera 2 image of the lensing cluster Abell 370 (z=0.37). By combining modelled field galaxy counts at this wavelength with a detailed mass model for the cluster, we develop techniques for predicting the expect

Thomas H. Reiprich, Hans Boehringer

A sample of one hundred and six X-ray galaxy clusters has been analysed in detail. Here we give the observed X-ray luminosity - gravitational mass relation. Possible future applications include conversion of empirical cluster luminosity functions to mass functions and conversion of simulated mass functions to luminosity functions.

S. E. Woosley, A. I. MacFadyen, A. Heger

A diverse range of phenomena is possible when a black hole experiences very rapid accretion from a disk due to the incomplete explosion of a massive presupernova star endowed with rotation. In the most extreme case, the outgoing shock fails promptly in a rotating helium star, a black hole and an accretion disk form, and a strong gamma-ray burst (GRB) results

Hyunju Jeong, Dongsu Ryu, T. W. Jones, Adam Frank

We have carried out simulations of the nonlinear evolution of the magnetohydrodynamic (MHD) Kelvin-Helmholtz (KH) instability for compressible fluids in $2\frac{1}{2}$-dimensions, extending our previous work by Frank et al (1996) and Jones \etal (1997). In the present work we have simulated flows in the x-y plane in which a ``sheared&#39;&#39; magnetic field

Paul Martini, Richard W. Pogge

We present an investigation of possible fueling mechanisms operating in the inner kiloparsec of Seyfert galaxies. We analyze visible and near-infrared Hubble Space Telescope images of 24 Seyfert 2s from the CfA Redshift Survey sample. In particular, we are searching for the morphological signatures of dynamical processes reponsible for transporting gas from

Jonathan E. Baker, Marc Davis, Huan Lin

The pair-weighted relative velocity dispersion of galaxies provides a measure of the thermal energy of fluctuations of the observed galaxy distribution, but the measure is difficult to interpret and is very sensitive to the existence of rare, rich clusters of galaxies. Several alternative statistical procedures have recently been suggested to relieve these p

A. Udalski, M. Szymanski, M. Kubiak, G. Pietrzynski

We present Period-Luminosity-Color and Period-Luminosity relations of classical Cepheids constructed for about 1280 Cepheids from the LMC and 2140 from the SMC. High quality BVI observations (120-360 epochs in the I-band and 15-40 in the BV-bands) were collected during the OGLE-II microlensing experiment. The I-band diagrams of the LMC show very small scatte

Phillip Helbig

I present constraints on cosmological parameters in the lambda_0-Omega_0 plane from a joint analysis of gravitational lensing statistics (astro-ph/9904175) and the magnitude-redshift relation for Type Ia supernovae (astro-ph/9812133 and astro-ph/9805201). I discuss reasons why this particular combination of tests is important and how the constraints can be i

Bohdan Paczynski

A toy model of a disk undergoing steady state accretion onto a black hole is presented. The disk is in a hydrostatic equilibrium for all radii r > r_{in}, with the inner disk radius located between the marginally stable and marginally bound orbits: r_{ms} > r_{in} > r_{mb}. Matter flows from the disk through a narrow cusp at r_{ms} and falls freely into the

Donald Q. Lamb, Daniel E. Reichart

The recent evidence that the light curves and the spectra of the afterglows of GRB 970228 and GRB 980326 appear to contain a SN component, in addition to a relativistic shock wave component, provide direct clues that at least the long GRBs detected by BeppoSAX are a result of the collapse of massive stars. We show that, if this is indeed the case, GRBs and t

Tatsuya Ueno

We discuss a (10+2)D N=(1,1) superalgebra and its projections to M-theory, type IIA and IIB algebras. From the complete classification of a second-rank central term valued in the so(10,2) algebra, we find all possible BPS states coming from this term. We show that, among them, there are two types of 1/2-susy BPS configurations; one corresponds to a super (2+

E. Kh. Akhmedov

We consider phenomenologically allowed structures of the neutrino mass matrix in the case of three light neutrino species. Constraints from the solar, atmospheric and reactor neutrino experiments as well as those from the neutrinoless double beta decay are taken into account. Both hierarchical and quasi-degenerate neutrino mass cases are studied. Assuming ma

Ann E Nelson

I construct solutions to Einstein&#39;s equations in 6 dimensions with bulk cosmological constant and intersecting 4-branes. Solutions exist for a continuous range of 4-brane tension, with long distance gravity localized to a 3+1 dimensional Minkowski intersection, provided that the additional tension of the intersection satisfies one condition.

Alex Krasnitz, Raju Venugopalan

In very high energy nuclear collisions, the initial energy of produced gluons per unit area per unit rapidity, $dE/L^2/dη$, is equal to $f(g^2μL) (g^2μ)^3/g^2$, where $μ^2$ is proportional to the gluon density per unit area of the colliding nuclei. For an SU(2) gauge theory, we perform a non--perturbative numerical computation of the function $f(g^2μL)$. It

C. S. Kochanek, E. E. Falco, C. D. Impey, J. Lehar

Most gravitational lenses are early-type galaxies in relatively low density environments -- a ``field&#39;&#39; rather than a ``cluster&#39;&#39; population. We show that field early-type galaxies with 0 < z < 1, as represented by the lens galaxies, lie on the same fundamental plane as those in rich clusters at similar redshifts. We then use the fundamental

V. C. de Andrade, L. C. T. Guillen, J. G. Pereira

Relying upon the equivalence between a gauge theory for the translation group and general relativity, a teleparallel version of the original Kaluza-Klein theory is developed. In this model, only the internal space (fiber) turns out to be five dimensional, spacetime being kept always four dimensional. A five-dimensional translational gauge theory is obtained

A. Montanari, N. Sourlas

The &#34;turbo codes&#34;, recently proposed by Berrou et. al. are written as a disordered spin Hamiltonian. It is shown that there is a threshold Theta such that for signal to noise ratios v^2 / w^2 > Theta, the error probability per bit vanishes in the thermodynamic limit, i.e. the limit of infinitly long sequences. The value of the threshold has been comp

Zhilin Qu, Fagen Xie, Alan Garfinkel

We studied the stability of linear vortex filaments in 3-dimensional (3D) excitable media, using both analytical and numerical methods. We found an intrinsic 3D instability of vortex filaments that is diffusion-induced, and is due to the slower diffusion of the inhibitor. This instability can result either in a single helical filament or in chaotic scroll br

E. V. Deviatov, A. A. Shashkin, V. T. Dolgopolov, W. Hansen

We study the Coulomb pseudogap for tunneling into the two-dimensional electron system of high-mobility (Al,Ga)As/GaAs heterojunctions subjected to a quantizing magnetic field at filling factor $ν\leq 1$. Tunnel current-voltage characteristics show that for the double maximum observed in the tunnel resistance at $ν\approx 1$ the pseudogap is linear in energy

Oliver Jahn

A relation between the total instanton number and the quantum-numbers of magnetic monopoles that arise in general Abelian gauges in SU(2) Yang-Mills theory is established. The instanton number is expressed as the sum of the `twists&#39; of all monopoles, where the twist is related to a generalized Hopf invariant. The origin of a stronger relation between ins

J. K. Kowalczynski

An exact solution of the current-free Einstein-Maxwell equations with the cosmological constant is presented. It is of Petrov type II, and its double principal null vector is geodesic, shear-free, expanding, and twisting. The solution contains five constants. Its electromagnetic field is non-null and aligned. The solution admits only one Killing vector and i

Mikhail Titov, Yan Fyodorov

The frequency dependent time delay correlation function $K(Ω)$ is studied analytically for a particle reflected from a finite one-dimensional disordered system. In the long sample limit $K(Ω)$ can be used to extract the resonance width distribution $ρ(Γ)$. Both quantities are found to decay algebraically as $Γ^{-ν}$, and $Ω^{-ν}$, $ν\simeq 1.25$ in a large r

Geza Levai, Pinaki Roy

A general procedure is presented to construct conditionally solvable (CES) potentials using the techniques of supersymmetric quantum mechanics.The method is illustrated with potentials related to the harmonic oscillator problem.Besides recovering known results,new CES potentials are also obtained within the framework of this general approach.The conditions u

C. P. Burgess, K. Zuber

The recently-discovered, nearby young supernova remnant in the southeast corner of the older Vela supernova remnant may have been seen in measurements of nitrate abundances in Antarctic ice cores. Such an interpretation of this twenty-year-old ice-core data would provide a more accurate dating of this supernova than is possible purely using astrophysical tec

J. Hashida, T. Morozumi, A. Purwanto

We study the neutrino mixing matrix (the MNS matrix) in the seesaw model. By assuming a large mass hierarchy for the heavy right-handed Majorana mass, we show that, in the diagonal Majorana base, the MNS matrix is determined by a unitary matrix, $S$, which transforms the neutrino Yukawa matrix, $y_ν$, into a triangular form, $y_{\triangle}$. The mixing matri

Sungho Lee, Changbom Park

We have measured the correlation functions of the optically selected clusters of galaxies in the Abell and the APM catalogs, and of the X-ray clusters in the X-ray-Brightest Abell-type Clusters of galaxies (XBACs) catalog and the Brightest Clusters Sample (BCS). The same analysis method and the same method of characterizing the resulting correlation function

D. Falcone

Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate the heavy neutrino masses under the hypotheses that the mixing in the Dirac leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that $M_ν \sim M_u$ or $M_e$, where $M_ν$ is the Dirac mass matrix of neutrinos. As a result we find that for $M_ν \sim M_u$ the vacuum

Yasumasa Tsukamoto, Norio Kawakami

We study the critical properties of one-dimensional electron systems with the $1/r^α$-type long-range interaction ($α\ge 1$). Using bosonization methods, we discuss how the 1D system exhibits a crossover from the Tomonaga-Luttinger liquid to the Wigner crystal when $α\to 1$. In particular, a detailed analysis is given to the Fermi-edge singularity phenomena

B. S. Zou, G. X. Peng, R. G. Ping, H. C. Chiang

For $J/Ψ\to\bar pp π^0$ and $\bar ppπ^+π^-$, the $π^0p$ and $pπ^+π^-$ systems are limited to be pure isospin 1/2 due to isospin conservation. This is a big advantage in studying $N^*$ resonances from $J/Ψ$ decays, compared with $πN$ and $γN$ experiments. The process $J/Ψ\to\bar pN^*$ or $p\bar N^*$ provides a new way to probe the internal structure of the $N

Fuqiang Wang, N. Xu

The baryon phase-space density at mid-rapidity from central heavy-ion collisions is estimated from proton spectra with interferometry and deuteron coalescence measurements. It is found that the mid-rapidity phase-space density of baryons is significantly lower at the SPS than the AGS, while those of total particles (pion + baryon) are comparable. Thermal and

S. Gardner, G. Valencia

In the analysis of ε^\prime/εit has been traditional to consider the isospin-breaking effects arising from electroweak-penguin contributions and from π^0-ηand π^0-η^\prime mixing, yet additional isospin-violating effects exist. In particular, we study the isospin violation which arises from the u-d quark mass difference in the hadronization of the gluonic pe

Philip R. Page

We provide an overview of theoretical developments on hybrid mesons and glueballs in the last year at this turn of the millenium conference. Cracks in potential models of conventional mesons are developing. Hybrid meson adiabatic surfaces have been calculated and interpreted, experimental J^PC exotics have hybrid meson, four-quark state or non-resonant inter

F. Wang, H. Liu, H. Sorge, N. Xu

We present a systematic study of the kaon to pion multiplicity ratios (K+/pi+ and K-/pi-) in heavy-ion collisions from AGS to RHIC energy using the Relativistic Quantum Molecular Dynamics (RQMD) model. The model satisfactorily describes the available experimental data on K+/pi+ and K-/pi-. Within the model, we find that the strong increase of the ratios with

Sergey I. Agafonov, Alexander I. Bobenko

A discrete analogue of the holomorphic map z^a is studied. It is given by a Schramm&#39;s circle pattern with the combinatorics of the square grid. It is shown that the corresponding immersed circle patterns lead to special separatrix solutions of a discrete Painleve equation. Global properties of these solutions, as well as of the discrete $z^a$ are establi

Mark Hillery

A quantum key distribution scheme based on the use of displaced squeezed vacuum states is presented. The states are squeezed in one of two field quadrature components, and the value of the squeezed component is used to encode a character from an alphabet. The uncertainty relation between quadrature components prevents an eavesdropper from determining both wi

Anu Venugopalan

We consider the interaction of a quantum system (spin-1/2) with a macroscopic quantum apparatus (harmonic oscillator) which in turn is coupled to a bath of harmonic oscillators. Exact solutions of the Markovian Master equation show that the reduced density matrix of the system-apparatus combine decoheres to a statistical mixture where up and down spins event

Miloslav Znojil

The recently proposed PT-symmetric quantum mechanics works with complex potentials which possess, roughly speaking, a symmetric real part and an anti-symmetric imaginary part. We propose and describe a new exactly solvable model of this type. It is defined as a specific analytic continuation of the shape-invariant potential of Morse. In contrast to the latte

Dennis Bonatsos, N. Karoussos, P. P. Raychev, R. P. Roussev

Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal clusters, as well as to theoretical predictions of jellium models, Woods--Saxon and wine bottle potentials, and to the classification scheme using the 3n+l pseudo quantum number. The 3-dimensional q-deforme

Dennis Bonatsos, C. Daskaloyannis

Various applications of quantum algebraic techniques in nuclear structure physics and in molecular physics are briefly reviewed and a recent application of these techniques to the structure of atomic clusters is discussed in more detail.

C. H. Woo

A distinction is made between two kinds of consistent histories: (1) robust histories consistent by virtue of decoherence, and (2) verifiable histories consistent through the existence of accessible records. It is events in verifiable histories which describe amplified quantum fluctuations. If the consistent-histories formalism is to improve on the Copenhage

Edward R. Floyd

We present a parabolic approximation that incorporates reflection. With this approximation, there is no need to solve the parabolic equation for a coupled pair of solutions consisting of the incident and reflected waves. Rather, this approximation uses a synthetic wave whose spectral components manifest the incident and reflected waves.

Hanns Walter Müller, Andreas Engel

Part of the field dependent dissipation in ferrofluids occurs due to the rotational motion of the ferromagnetic grains relative to the viscous flow of the carrier fluid. The classical theoretical description due to Shliomis uses a mesoscopic treatment of the particle motion to derive a relaxation equation for the non-equilibrium part of the magnetization. Co

Soon-Tae Hong, Dong-Pil Min

Treating perturbatively the flavor symmetry breaking effects resided in the wave function as well as in the SU(3) Lagrangian, we calculate the strange form factors of decuplet baryons. The higher dimensional representation mixing components in the baryon wave function of the deccuplet baryons are found to yield the important contributions to the strange form

Dennis Bonatsos, C. Daskaloyannis

Quantum algebras are a mathematical tool which provides us with a class of symmetries wider than that of Lie algebras, which are contained in the former as a special case. After a self-contained introduction to the necessary mathematical tools (q-numbers, q-analysis, q-oscillators, q-algebras), the SUq(2) rotator model and its extensions, the construction of

Manfred Salmhofer, Christian Wieczerkowski

We derive norm bounds that imply the convergence of perturbation theory in fermionic quantum field theory if the propagator is summable and has a finite Gram constant. These bounds are sufficient for an application in renormalization group studies. Our proof is conceptually simple and technically elementary; it clarifies how the applicability of Gram bounds

Gerald Kaiser

An extension of potential theory in R^n is obtained by continuing the Euclidean distance function holomorphically to C^n. The resulting Newtonian potential is generated by an extended source distribution D(z) in C^n whose restriction to R^n is the delta function. This provides a natural model for extended particles in physics. In C^n, interpreted as complex

Neil S. Trudinger, Xu-Jia Wang

In our previous paper on this topic, we introduced the notion of k-Hessian measure associated with a continuous k-convex function in a domain \Om in Euclidean n-space, k=1,...,n, and proved a weak continuity result with respect to local uniform convergence. In this paper, we consider k-convex functions, not necessarily continuous, and prove the weak continui

Henry H. Kim, Freydoon Shahidi

The purpose of this paper is to prove the long awaited holomorphy of the third symmetric power L-functions attached to nonmonomial cusp forms of GL_2 over an arbitrary number field on the whole complex plane.

Carlos E. Kenig, Tatiana Toro

One of the basic aims of this paper is to study the relationship between the geometry of ``hypersurface like&#39;&#39; subsets of Euclidean space and the properties of the measures they support. In this context we show that certain doubling properties of a measure determine the geometry of its support. A Radon measure is said to be doubling with constant C i

Vadim Yu. Kaloshin

Let M be a compact manifold. We call a mapping f in C^r(M,M) an Artin-Mazur mapping if the number of isolated periodic points of f^n grows at most exponentially in n. Artin and Mazur posed the following problem: What can be said about the set of Artin-Mazur mappings with only transversal periodic orbits? Recall that a periodic orbit of period n is called tra

Velimir Jurdjevic

The contributions of Sophya Kowalewski to the integrability theory of the equations for the heavy top extend to a larger class of Hamiltonian systems on Lie groups; this paper explains these extensions, and along the way reveals further geometric significance of her work in the theory of elliptic curves. Specifically, in this paper we shall be concerned with

Vincent Franjou, Eric M. Friedlander, Alexander Scorichenko, Andrei Suslin

In recent years, there has been considerable success in computing Ext-groups of modular representations associated to the general linear group by relating this problem to one of computing Ext-groups in functor categories. In this paper, we extend our ability to make such Ext-group calculations by establishing several fundamental results. Throughout this pape

Michael Christ, Alexander Nagel, Elias M. Stein, Stephen Wainger

The purpose of this paper is to prove the L^p boundedness of singular Radon transforms and their maximal analogues. These operators differ from the traditional singular integrals and maximal functions in that their definition at any point x in R^n involves integration over a k-dimensional submanifold of R^n, depending on x, with k < n. The role of the underl

Luchezar L. Avramov

Classical definitions of locally complete intersection (l.c.i.) homomorphisms of commutative rings are limited to maps that are essentially of finite type, or flat. The concept introduced in this paper is meaningful for homomorphisms phi : R \longrightarrow S of commutative noetherian rings. It is defined in terms of the structure of phi in a formal neighbor

Alan Adolphson, Steven Sperber

We prove a vanishing theorem for the p-adic cohomology of exponential sums on affine space. In particular, we obtain new classes of exponential sums on affine space that have a single nonvanishing p-adic cohomology group. The dimension of this cohomology group equals a sum of Milnor numbers.

Fouad Elzein, András Némethi

Let Y be a normal crossing divisor in the smooth projective algebraic variety X (defined over ${\mathbb C}$) and let U be a tubular neighbourhood of Y in X. We construct homological cycles generating $H_*(A,B)$, where (A,B) is one of the following pairs $(Y,\emptyset)$, (X,Y), (X,X-Y), $(X-Y,\emptyset)$ and $(\partial U,\emptyset)$. The construction is compa

Sheon-Young Kang, Israel Koltracht, George Rawitscher

A new highly accurate numerical approximation scheme based on a Gauss type Clenshaw-Curtis Quadrature for Fredholm integral equations of the second kind, whose kernel is either discontinuous or not smooth along the main diagonal, is presented. This scheme is of spectral accuracy when the kernel is infinitely differentiable away from the main diagonal, and is

Sam Evens, Jiang-Hua Lu

We study Lagrangian subalgebras of a semisimple Lie algebra with respect to the imaginary part of the Killing form. We show that the variety $\Lagr$ of Lagrangian subalgebras carries a natural Poisson structure $Π$. We determine the irreducible components of $\Lagr$, and we show that each irreducible component is a smooth fiber bundle over a generalized flag

Jiang-Hua Lu

Let G be a finite dimensional simple complex group equipped with the standard Poisson Lie group structure. We show that all G-homogeneous (holomorphic) Poisson structures on $G/H$, where $H \subset G$ is a Cartan subgroup, come from solutions to the Classical Dynamical Yang-Baxter equations which are classified by Etingof and Varchenko. A similar result hold

Alexander I. Bobenko

A generic surface in Euclidean 3-space is determined uniquely by its metric and curvature. Classification of all special surfaces where this is not the case, i.e. of surfaces possessing isometries which preserve the mean curvature, is known as the Bonnet problem. Regarding the Bonnet problem, we show how analytic methods of the theory of integrable systems -

Nigel Hitchin

A result of Jost and Zuo is used to show that for a large class of finite-dimensional hyperkähler quotients, the only L2 harmonic forms lie in the middle dimension, and are of type (k,k) with respect to all complex structures. The argument is extended to some moduli spaces which appear as infinite-dimensional quotients such as Higgs bundle and SU(2) monopole

Deepak Parashar, Roger J. McDermott

The quantum group GL_p,q(2) is known to be related to the Jordanian GL_h,h&#39;(2) via a contraction procedure. It can also be realised using the generators of the Hopf algebra G_r,s. We contract the G_r,s quantum group to obtain its Jordanian analogue G_m,k, which provides a realisation of GL_h,h&#39;(2) in a manner similar to the q-deformed case.

Gunther Cornelissen

Let G be the separable Galois group of a finite field F of characteristic p, and X/F an imaginary hyperelliptic curve such that G acts transitively on its set W(X) of Weierstrass points. The existence of a G-invariant 2-torsion point on the Jacobian J(X) of X depends only on the parity of |W(X)|, but for large enough |F|, there exist two such curves X and X&

G. W. Patrick

An interesting situation occurs when the linearized dynamics of the shape of a formally stable Hamiltonian relative equilibrium at nongeneric momentum 1:1 resonates with a frequency of the relative equilibrium&#39;s generator. In this case some of the shape variables couple to the group variables to first order in the momentum perturbation, and the first ord

Laurent Baulieu, Daniel Zwanziger

We propose a 5-dimensional definition for the physical 4D-Yang-Mills theory. The fifth dimension corresponds to the Monte-Carlo time of numerical simulations of QCD_4. The 5-dimensional theory is a well-defined topological quantum field theory that can be renormalized at any given finite order of perturbation theory. The relation to non-perturbative physics

Joan Simón

The general criteria for finding bosonic supersymmetric worldvolume solitons is reviewed. We concentrate on D-branes, discussing in particular, bion/dyon solutions and D3 branes on NS5 backgrounds.

Carlo Angelantonj

In this short note we review the main features of open-string orbifolds with a quantised flux for the NS-NS antisymmetric tensor in the context of the open descendants of non-supersymmetric asymmetric orbifolds with a vanishing cosmological constant.

Dennis Bonatsos, C. Daskaloyannis, K. Kanakoglou

The general properties of the ordinary and generalized parafermionic algebras are discussed. The generalized parafermionic algebras are proved to be polynomial algebras. The ordinary parafermionic algebras are shown to be connected to the Arik-Coon oscillator algebras.

Jan B. Thomassen

There is a conceptual error in the main argument of this paper (essentially a regularization scheme is changed in the middle of a calculation), and therefore it is withdrawn. Interested readers are instead referred to hep-th/9811137.

Kingman Cheung, Greg Landsberg

In the model of Arkani-Hamed, Dimopoulos, and Dvali where gravity is allowed to propagate in the extra dimensions of very large size, virtual graviton exchange between the standard model particles can give rise to signatures that can be tested in collider experiments. We study these effects in dilepton and diphoton production at hadron colliders. Specificall

Frank E. Paige

The status of event generators for SUSY processes at future Linear Colliders is briefly reviewed.

Frank E. Paige

If SUSY exists at the TeV scale, finding it at the LHC should be quite easy. The more difficult problem is to separate the various SUSY channels and to measure masses and other parameters. Substantial progress on this has been made within the ATLAS and CMS Collaborations.

E. Boos, M. Dubinin

The process of single W-boson production at the energies of Next Linear Colliders is considered. We discuss in details the contributions from s and t channel diagrams, technical aspects of the complete tree level calculation with a finite W width, and the quark mass effects.

Nora Brambilla, Antonio Vairo

We discuss heavy quarkonium in the framework of pNRQCD, a QCD effective theory appropriate for the study of heavy quark bound systems.

Marco A. Diaz, Javier Ferrandis, Jose W. F. Valle

We study the predictions for M_top, tan(beta) and V_cb in a popular texture ansatze for the fermion mass matrices. We do this both for the Minimal Supersymmetric Standard Model (MSSM) and for the simplest model (MSSM-BRpV) where a bilinear R-Parity violating term is added to the superpotential. We find that taking the experimental values for M_top and V_cb a

Nora Brambilla

We present model independent predictions on the short range behavior of the energies of the gluonic excitations between static quarks (hybrid potentials) in an effective field theory framework (pNRQCD).

E. de Rafael

I report on recent progress in calculating electroweak processes within the framework of QCD in the 1/Nc expansion.