December 1999 arXiv papers — page 20

CDF Collaboration

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb-1 of p anti-p collisions at s**(1/2) = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transver

Scott A. Hughes

Space-based gravitational-wave interferometers such as LISA will be sensitive to the inspiral of stellar mass compact objects into black holes with masses in the range of roughly 10^5 solar masses to (a few) 10^7 solar masses. During the last year of inspiral, the compact body spends several hundred thousand orbits spiraling from several Schwarzschild radii

P. R. Williams, B. F. Schutz

We describe an efficient method of matched filtering over long (greater than 1 day) time baselines starting from Fourier transforms of short durations (roughly 30 minutes) of the data stream. This method plays a crucial role in the search algorithm developed by Schutz and Papa for the detection of continuous gravitational waves from pulsars. Also, we discuss

B. Mashhoon, F. Gronwald, H. I. M. Lichtenegger

The main theoretical aspects of gravitomagnetism are reviewed. It is shown that the gravitomagnetic precession of a gyroscope is intimately connected with the special temporal structure around a rotating mass that is revealed by the gravitomagnetic clock effect. This remarkable effect, which involves the difference in the proper periods of a standard clock i

William M. Pezzaglia

A solution to the 50 year old problem of a spinning particle in curved space has been recently derived using an extension of Clifford calculus in which each geometric element has its own coordinate. This leads us to propose that all the laws of physics should obey new polydimensional metaprinciples, for which Clifford algebra is the natural language of expre

Theodore G. Erler

We introduce an original approach to geometric calculus in which we define derivatives and integrals on functions which depend on extended bodies in space--that is, paths, surfaces, and volumes etc. Though this theory remains to be fully completed, we present it at its current stage of development, and discuss it's connection to physical research, in par

V. B. Braginsky, M. L. Gorodetsky, S. P. Vyatchanin

Thermodynamical fluctuations of temperature in mirrors of gravitational wave antennae are transformed through thermal expansion coefficient into additional noise. This source of noise, which may also be interpreted as fluctuations due to thermoelastic damping, may not be neglected and leads to the necessity to reexamine the choice of materials for the mirror

F. Pierre, H. Pothier, D. Esteve, M. H. Devoret

We have measured with a tunnel probe the energy distribution function of quasiparticles in silver diffusive wires connected to two large pads (``reservoirs''), between which a bias voltage was applied. From the dependence in energy and bias voltage of the distribution function we have inferred the energy exchange rate between quasiparticles. In contr

A. B. Gougam, F. Pierre, H. Pothier, D. Esteve

We have measured the phase coherence time, $τ_ϕ,$ in long, narrow wires of Au, Ag, and Cu, over the temperature range 40 mK-6 K. In the Cu and Au wires, $τ_ϕ$ saturates at low temperature. In the Ag wire, $τ_ϕ$ continues to increase down to the lowest temperatures measured; moreover, its temperature dependence below about 1 K is consistent with theoretical p

R. Mélin

We address the problem of antiferromagnetism in a two dimensional model of doped spin-Peierls system, at the classical and quantum levels. A Bethe-Peierls solution is derived for the classical model, with an ordering temperature proportional to the doping concentration. The quantum model is treated in a cluster renormalization group showing a finite randomne

B. Schmittmann, R. K. P. Zia, Wannapong Triampo

We consider the disordering dynamics of an interacting binary alloy with a small admixture of vacancies which mediate atom-atom exchanges. Starting from a perfectly phase-segregated state, the system is rapidly heated to a temperature in the disordered phase. A suitable disorder parameter, namely, the number of broken bonds, is monitored as a function of tim

Hiroshi Shimahara

We propose a mechanism of nodeless d-wave superconductivity in a quasi-one-dimensional organic superconductor under anion order. It is shown that split of the Fermi surfaces due to the anion order eliminates the line nodes of a d-wave gap function on the Fermi surfaces, and a small finite energy gap appears in the quasi-particle excitations of superconductiv

E. Cappelluti, R. Zeyher

Impurity substitution of Zn in La-214 and (Y,Ca)-123 high-T_c superconductors suppresses T_c but does not affect appreciably the onset of the pseudogap phase in the underdoped region nor optimal doping or the position of the inferred quantum critical point. Based on a 1/N expansion of the t-J model we explain these findings as well as the similar dependence

I. M. Suslov

Asymptotically exact results are obtained for the average Green function and the density of states in a Gaussian random potential for the space dimensionality d=4-epsilon over the entire energy range, including the vicinity of the mobility edge. For N\sim 1 (N is an order of the perturbation theory) only the parquet terms corresponding to the highest powers

Andrej Gendiar, Anton Surda

A modified density matrix renormalization group (DMRG) method is introduced and applied to classical two-dimensional models: the anisotropic triangular nearest- neighbor Ising (ATNNI) model and the anisotropic triangular next-nearest-neighbor Ising (ANNNI) model. Phase diagrams of both models have complex structures and exhibit incommensurate phases. It was

Masaru Onoda, Takahiro Mizusaki, Takaharu Otsuka, Hideo Aoki

To probe the nature of the even-fraction quantum Hall system, we have investigated the low-lying excitation spectrum by means of exact diagonalization for finite systems. We have found (i) a striking one-to-one correspondence (i.e., a shell structure) between the spectrum and those for free (composite) fermions, (ii) a surprisingly straight scaling plot for

Kazuhiro Sano

We study the Luttinger-liquid parameter $K_ρ$ of the Hubbard chain and the Hubbard ladder models by the ordinary perturbation method combined with the Luttinger-liquid relation. According to the Luttinger-liquid relation, the critical exponent $K_ρ$ is related to the charge susceptibility $χ_c$ and the Drude weight D by $ K\sbρ={1/2}(πχ_c D)^{1/2}$. By calcu

Sanghamitra Mukhopadhyay, K. C. Rustagi

We have calculated the contribution of intersubband transitions to the third order optical nonlinear susceptibility, $χ^{(3)}(ω,ω,ω)$ for nonresonant as well as resonant third harmonic generation and $χ^{(3)}(ω,-ω,ω)$ for nonlinear refraction and absorption. As examples, we consider InAs/AlSb and GaAs/GaAlAs quantum wells. The effects of finite barrier heigh

Jeroen M. Elzerman, Silvano De Franceschi, David Goldhaber-Gordon, Wilfred G. van der Wiel

We have studied the influence of microwave radiation on the transport properties of a semiconductor quantum dot in the Kondo regime. In the entire frequency range tested (10--50 GHz), the Kondo resonance vanishes by increasing the microwave power. This suppression of the Kondo resonance shows an unexpected scaling behavior. No evidence for photon-sideband fo

Kikuo Harigaya

Effects of the superconducting pair potential on the impurity scattering processes in metallic carbon nanotubes are studied theoretically. The backward scattering of electrons vanishes in the normal state. In the presence of the superconducting pair correlations, the backward scatterings of electron- and hole-like quasiparticles vanish, too. The impurity giv

S. N. Gurbatov

The present work is devoted to the evolution of random solutions of the unforced Burgers and KPZ equations in d-dimensions in the limit of vanishing viscosity. We consider a cellular model and as initial condition assign a value for the velocity potential chosen independently within each cell. We show that the asymptotic behavior of the turbulence at large t

Ranjeev Misra

We reanalyze the ASCA and BeppoSAX data of MCG-6-30-15, using a double zone model for the Iron line profile. In this model, the X-ray source is located around $\approx 10$ Schwarzschild radius and the regions interior and exterior to the X-ray source produce the line emission. We find that this model fits the data with similar reduced $χ^2$ as the standard s

Ranjeev Misra

We show that waves propagating in a transition disk can explain the short term temporal behavior of Cygnus X-1. In the transition disk model the spectrum is produced by saturated Comptonization within the inner region of the accretion disk where the temperature varies rapidly with radius. Recently, the spectrum from such a disk has been shown to fit the aver

Sylvie F. Beaulieu, Gerard F. Gilmore, Rachel A. Johnson, Stephen J. Smartt

As part of a large HST project to study the formation and evolution of rich star clusters in the Large Magellanic Cloud, we present results for the Galactic bulge metal-rich globular cluster NGC6553. HST observations using WFPC2, NICMOS and STIS were obtained for this cluster. The primarily reason for studying NGC6553 is to allow the possibility to transform

Bhaskar Datta, Arun V. Thampan, Ignazio Bombaci

Kilohertz quasi-periodic brightness oscillations (kHz QPOs) observed in certain X-ray burst sources may represent Keplerian frequencies in the inner regions of the accretion disk in such systems. If this assumption is strictly adhered to, we show here that if the central accretor in stellar X-ray burst sources is a strange star (made up of u, d and s quarks

Karl Gebhardt, Carlton Pryor, R. D. O'Connell, T. B. Williams

We have used an Imaging Fabry-Perot Spectrophotometer with the Adaptive Optics Bonnette on the Canada-France-Hawaii Telescope to measure stellar radial velocities in the globular cluster M15. An average seeing of 0.15" full-width at half maximum, with the best-seeing image having 0.09", allowed us to measure accurately the velocities for five stars w

D. A. Frail, S. R. Kulkarni, M. H. Wieringa, G. B. Taylor

We describe a ground-based effort to find and study afterglows at centimeter and millimeter wavelengths. We have observed all well-localized gamma-ray bursts in the Northern and Southern sky since BeppoSAX first started providing rapid positions in early 1997. Of the 23 GRBs for which X-ray afterglows have been detected, 10 have optical afterglows and 9 have

Igor V. Igumenshchev

Using two-dimensional simulations of non-radiative viscous rotating black hole accretion flows, we show that the flows with alpha~0.1-0.3 self-organize to form stationary unipolar or bipolar outflows accompanied by global meridional circulations. The required energy comes, with efficiency \~0.001-0.01, from the matter directly accreted onto black hole. Obser

S. Mereghetti, A. Tiengo, G. L. Israel, L. Stella

We report XTE and SAX observations of the X-ray pulsar RX J0146.9+612, the neutron star/Be binary system with the longest known spin period. Data obtained one month after the most recent outburst (July 1997), show that the source has returned to its normal luminosity of a few 10^34 erg/s while spin down continued at an average rate of about 5x10e-8 s/s.

C. Murali

The properties of the Magellanic Stream constrain the density of coronal gas in the distant Galactic halo. We show that motion through ambient gas can strongly heat Stream clouds, driving mass loss and causing evaporation. If the ambient gas density is too high, then evaporation occurs on unreasonably short timescales. Since heating dominates drag, tidal str

J. P. Gardner, S. A. Baum, T. M. Brown, C. M. Carollo

We present the imaging observations made with the Space Telescope Imaging Spectrograph of the Hubble Deep Field - South. The field was imaged in 4 bandpasses: a clear CCD bandpass for 156 ksec, a long-pass filter for 22-25 ksec per pixel typical exposure, a near-UV bandpass for 23 ksec, and a far-UV bandpass for 52 ksec. The clear visible image is the deepes

D. L. Clements

I present results from a deep 12 micron extragalactic survey conducted with the ISOCAM instrument. The survey covers about 0.1 sq. deg. in four fields and reaches a 5 sigma flux limit of about 500 microJy. 50 sources are identified to this flux limit. Of these, 37 are classified as galaxies on the basis of optical/mid-IR colours using identifications from th

Charles D. Dermer, James Chiang

Gamma-ray burst (GRB) engines are probed most intimately during the prompt gamma-ray luminous phase when the expanding blast wave is closest to the explosion center. Using GRBs 990123 and 940217 as guides, we briefly review observations of high-energy emission from GRBs and summarize some problems in GRB physics. γγtransparency arguments imply relativistic b

Bruce Elmegreen

The turnover in the stellar initial mass function (IMF) at low mass suggests the presence of two independent mass functions that combine in different ways above and below a characteristic mass given by the thermal Jeans mass in the cloud. In the random sampling model introduced earlier, the Salpeter IMF at intermediate to high mass follows primarily from the

D. Montes

Stellar kinematic groups (SKG) are kinematically coherent groups of stars that share a common origin. We have compiled (Montes et al. 1999; 2000) a sample of late-type stars of previously established members and possible new candidates to different young SKG (Local Association (20 - 150 Myr), Ursa Mayor group (300 Myr), Hyades supercluster (600 Myr), IC 2391

D. Montes, M. J. Fernandez-Figueroa, E. De Castro, M. Cornide

We present a kinematic study of a large sample of chromospherically active binaries (CAB) in order to determine their membership to representative young disk stellar kinematic groups: the Local Association (Pleiades moving group, 20 - 150 Myr), Ursa Mayor group (Sirius supercluster, 300 Myr), Hyades supercluster (800 Myr), IC 2391 supercluster (35 Myr) and C

A. Latorre, D. Montes, M. J. Fernandez-Figueroa

We have analysed several multiwavelength optical observations (H_alpha, H_beta, H_epsilon, Ca II H & K, Ca II IRT lines) of chromospherically active binary system OU Gem, taken in three observation runs: March 1996, April 1998 (using the SOFIN spectrograph and the Nordic Optical Telescope) and January 1999 (using the ESA-MUSICOS spectrograph and the Isaac Ne

M. R. Pestalozzi, A. O. Benz, J. E. Conway, M. Guedel

We report on 3.6 cm VLA and VLBA observations of YZ CMi and AD Leo, two nearby dMe stars. We resolve YZ CMi and can fit a circular symmetrical gaussian component of FWHP of 0.98 +/-0.2 mas, corresponding to an extent of the corona above the photosphere of 1.77 x 10^{10} +/-8.8 x 10^{9} cm or 0.7 +/-0.3 Rstar (Rstar refers to the photospheric radius). We obta

D. Montes, R. Lachaume, M. J. Fernandez-Figueroa

We present simultaneous spectroscopic observations taken during four observing runs (1996 to 1999) of H_alpha, H_beta, H_epsilon, Ca II H & K, and Ca II IRT lines of the chromospherically active binary BF Lyn. Both components have strong emission in the H_epsilon, Ca II H & K and Ca II IRT lines and a strong filling-in of the H_alpha and H_beta lines have be

C. Morisset, R. Gruenwald, S. M. Viegas

We present a new modeling tool for planetary nebulae, based on 3D photoionization calculations. Our goal is to show that all the information provided by observations, regarding kinematics and morphology, have to be consistently accounted for, in order to get a real insight of the object. Only 3D simulations offer this possibility. From models for two theoret

K. Sumiyoshi, H. Suzuki, K. Otsuki, M. Terasawa

We study the neutrino-driven wind from the proto-neutron star by the general relativistic hydrodynamical simulations. We examine the properties of the neutrino-driven wind to explore the possibility of the r-process nucleosynthesis. The numerical simulations with the neutrino heating and cooling processes are performed with the assumption of the constant neu

M. Juvela, P. Padoan

The high resolution and sensitivity provided by proposed Atacama Large Millimeter Array will reveal new small scale structures in many sources, e.g. star forming regions. Such inhomogeneities may not have been considered in the analysis of past observations but they will be essential to the understanding of future data. Radiative transfer methods are needed

K. L. Adelberger

The advent of 8m-class telescopes has made galaxies at 1 < z < 4 relatively easy to detect and study. This is a brief and incomplete review of some of the recent results to emerge from surveys at these redshifts. After describing different strategies for finding galaxies at z >~ 1, and the differences (and similarities) in the resulting galaxy samples, I sum

V. I. Dokuchaev, Yu. N. Eroshenko, L. M. Ozernoy

Non-steady and eruptive phenomena in quasars are thought to be associated with the Eddington or super-Eddington luminous stage. Although there is no lack in hypotheses about the total duration of such a stage, the latter remains essentially unknown. We calculate the duration of quasar luminous phase in dependence upon the initial mass of a newborn massive bl

C. -H. Rosie Chen, You-Hua Chu, Robert A. Gruendl, Sean D. Points

Bright X-ray emission has been detected in superbubbles in the Large Magellanic Cloud (LMC), and it is suggested that supernova remnants (SNRs) near the inner shell walls are responsible for this X-ray emission. To identify SNR shocks in superbubble interiors, we have obtained HST WFPC2 emission-line images of the X-ray-bright superbubbles DEM L 152 and DEM

Daniel J. Eisenstein, Matias Zaldarriaga

We reconsider the inference of spatial power spectra from angular clustering data and show how to include correlations in both the angular correlation function and the spatial power spectrum. Inclusion of the full covariance matrices loosens the constraints on large-scale structure inferred from the APM survey by over a factor of two. We present a new invers

J. B. Hutchings, L. Edwards

This paper discusses the galaxy populations of three rich clusters, with redshift 0.19 (0839+29), 0.24 (1231+15), and 0.32 (1224+20), from the database of the CNOC1 consortium. The data consist of spectra of 52 cluster members for 0839+29, 30 members for 1224+15, and 82 members for 1231+15, and there are comparable numbers of field galaxy spectra. 0839+29 is

Philip J. Armitage, Brad M. S. Hansen

Recent discoveries of extrasolar planets at small orbital radii, or with significant eccentricities, indicate that interactions between massive planets and the disks of gas and dust from which they formed are vital for determining the final shape of planetary systems. We show that if this interaction occurs at an early epoch, when the protoplanetary disc was

J. Doyne Farmer, Andrew W. Lo

In this review article we explore several recent advances in the quantitative modeling of financial markets. We begin with the Efficient Markets Hypothesis and describe how this controversial idea has stimulated a number of new directions of research, some focusing on more elaborate mathematical models that are captable of rationalizing the empirical facrts,

M. R. Corbin, W. D. Vacca, E. O&#39;Neil, R. I. Thompson

We present positions, magnitudes, sizes and morphological classifications for 111 galaxies discovered in the Hubble Space Telescope NICMOS Camera 1 and Camera 2 parallel fields. We combine the magnitudes measured in the JHK-analog filters with those from deep ground-based images in V and/or R to measure photometric redshifts for 71 objects using Bruzual-Char

Eugene A. Mirabelli, Martin Schmaltz

We explore a mechanism for generating the Yukawa hierarchies by displacing the left- and right-handed components of the Standard Model fermions in a higher-dimensional space. We find a unique configuration of displacements which fits all quark and lepton masses and mixing angles, with a prediction for the strange quark mass m_s = 120 MeV.

G. Clement, A. Fabbri

We derive and analyze exact static solutions to the gravitating O(3) $σ$ model with cosmological constant in (2+1) dimensions. Both signs of the gravitational and cosmological constants are considered. Our solutions include geodesically complete spacetimes, and two classes of black holes.

Erik Verlinde

The AdS/CFT correspondence implies that the effective action of certain strongly coupled large $N$ gauge theories satisfy the Hamilton-Jacobi equation of 5d gravity. Using an analogy with the relativistic point particle, I construct a low energy effective action that includes the Einstein action and obeys a Callan-Symanzik-type RG-flow equation. It follows f

Ruben L. Pakman

Duality symmetric electromagnetic action a la Schwarz-Sen is shown to appear naturally in a chain of equivalent actions which interchange equations of motion with Bianchi identities. Full symmetry of the electromagnetic stress tensor is exploited by generalizing this duality symmetric action to allow for a space-time dependent mixing angle between electric a

R. J. Nicholas, K. Takashina, M. Lakrimi, B. Kardynal

The electrical transport properties of a bipolar InAs/GaSb system have been studied in magnetic field. The resistivity oscillates between insulating and metallic behaviour while the quantum Hall effect shows a digital character oscillating from 0 to 1 conducatance quantum e^2/h. The insulating behaviour is attributed to the formation of a total energy gap in

J. Brachmann, A. Dumitru, H. Stöcker, W. Greiner

We investigate the excitation function of quark-gluon plasma formation and of directed in-plane flow of nucleons in the energy range of the BNL-AGS and for the E(Lab)=40AGeV Pb+Pb collisions performed recently at the CERN-SPS. We employ the three-fluid model with dynamical unification of kinetically equilibrated fluid elements. Within our model with first-or

Amir H. Abbassi

A more rigorous treatment of the Schwarzschild metric by making use of the energy-momentum tensor of a single point particle as source term shows that $g_{00}=-\{1-\frac{2GM}{c^2r}-\frac{8G^2 M^2}{c^4 r^2}(θ(r)-1)\}\exp [2(θ(r)-1)]$ $g_{rr}=\{1-\frac{2GM}{c^2r}-\frac{8G^2 M^2}{c^4 r^2}(θ(r)-1)\}^{-1}$ The existence of a discontinuity at r=0 leads to an infin

J. M. Carmona, A. Pelissetto, E. Vicari

We consider the Ginzburg-Landau Hamiltonian with a cubic-symmetric quartic interaction and compute the renormalization-group functions to six-loop order in d=3. We analyze the stability of the fixed points using a Borel transformation and a conformal mapping that takes into account the singularities of the Borel transform. We find that the cubic fixed point

Antonaldo Diaferio, Rashid A. Sunyaev, Adi Nusser

We identify high density regions of supercluster size in high resolution N-body simulations of a representative volume of three Cold Dark Matter Universes. By assuming that (1) the density and peculiar velocities of baryons trace those of the dark matter, and (2) the temperature of plasma is proportional to the velocity dispersion of the dark matter particle

U. Heber, I. N. Reid, K. Werner

Four members of the new class of pulsating sdB stars are analysed from Keck HIRES spectra using NLTE and LTE model atmospheres. Atmospheric parameters (Teff, log g, log(He/H)), metal abundances and rotational velocities are determined. Balmer line fitting is found to be consistent with the helium ionization equilibrium for PG1605+072 but not so for PG1219+53

Blas Echebarria, Hermann Riecke

Using coupled Ginzburg-Landau equations, the dynamics of hexagonal patterns with broken chiral symmetry are investigated, as they appear in rotating non-Boussinesq or surface-tension-driven convection. We find that close to the secondary Hopf bifurcation to oscillating hexagons the dynamics are well described by a single complex Ginzburg-Landau equation (CGL

R. Guo, L. E. Cross, S-E. Park, B. Noheda

High resolution x-ray powder diffraction measurements on poled PbZr(1-x)TixO3 (PZT) ceramic samples close to the rhombohedral-tetragonal phase boundary (the so-called morphotropic phase boundary, MPB) have shown that for both rhombohedral and tetragonal compositions, the piezoelectric elongation of the unit cell does not occur along the polar directions but

D. H. Tchrakian, F. Zimmerschied

The Kalb-Ramond monopole, as discussed by Nepomechie, is identical with the (singular) Dirac monopole in d=3 dimensions. The latter can be described by the (regular) &#39;t Hooft-Polyakov monopole, via the &#39;t Hooft tensor construction. This construction is extended to arbitrary odd dimensions by performing the d=5 case explicitly, exploiting the (regular

A. C. Aguiar Pinto, M. C. Nemes, J. G. Peixoto de Faria, M. T. Thomaz

The experimental observation of effects due to Berry&#39;s phase in quantum systems is certainly one of the most impressive demonstrations of the correctness of the superposition principle in quantum mechanics. Since Berry&#39;s original paper in 1984, the spin 1/2 coupled with rotating external magnetic field has been one of the most studied models where th

R. Brustein, G. Veneziano

The identification of a causal-connection scale motivates us to propose a new covariant bound on entropy within a generic space-like region. This &#34;causal entropy bound&#34;, scaling as the square root of EV, and thus lying around the geometric mean of Bekenstein&#39;s S/ER and holographic S/A bounds, is checked in various &#34;critical&#34; situations. I

Mai Dinh, Nicolas Borghini, Jean-Yves Ollitrault

The methods currently used to measure collective flow in nucleus--nucleus collisions assume that the only azimuthal correlations between particles are those arising from their correlation with the reaction plane. However, quantum HBT correlations also produce short range azimuthal correlations between identical particles. This creates apparent azimuthal anis

Miloslav Znojil

Version 1: The well known Eckart&#39;s singular s-wave potential is PT-symmetrically regularized and continued to the whole real line. The new model remains exactly solvable and its bound states remain proportional to Jacobi polynomials. Its real and discrete spectrum exhibits several unusual features. Version 2: Parity times time-reversal symmetry of comple

U. Frisch, J. Bec, B. Villone

We are interested in the tail behavior of the pdf of mass density within the one and $d$-dimensional Burgers/adhesion model used, e.g., to model the formation of large-scale structures in the Universe after baryon-photon decoupling. We show that large densities are localized near ``kurtoparabolic&#39;&#39; singularities residing on space-time manifolds of co

Gi-Chol Cho, Kaoru Hagiwara

We study constraints on the supersymmetric standard model from the updated electroweak precision measurements --- the Z-pole experiments and the $W$-boson mass measurements. The supersymmetric-particle contributions to the universal gauge-boson-propagator corrections are parametrized by the three oblique parameters Sz, Tz and mw. The oblique corrections, the

Marc Henneaux, Bernard Knaepen

The complete proof of a theorem announced in [1] on the consistent interactions for (non-chiral) exterior form gauge fields is given. The theorem can be easily generalized to the analysis of anomalies. Its proof amounts to computing the local BRST cohomology H^0(s|d) in the space of local n-forms depending on the fields, the ghosts, the antifields and their

Peter Presnajder

We describe the scalar and spinor fields on noncommutative sphere starting from canonical realizations of the enveloping algebra ${\cal A}={\cal U}{u(2))}$. The gauge extension of a free spinor model, the Schwinger model on a noncommutative sphere, is defined and the model is quantized. The noncommutative version of the model contains only a finite number of

Laura Andrianopoli, Martijn Derix, Gary W. Gibbons, Carlos Herdeiro

We show how non-near horizon p-brane theories can be obtained from two embedding constraints in a flat higher dimensional space with 2 time directions. In particular this includes the construction of D3 branes from a flat 12-dimensional action, and M2 and M5 branes from 13 dimensions. The worldvolume actions are determined by constant forms in the higher dim

Lars Kjaergaard, Paul Mansfield

We describe a general method for calculating the infra-red limit of physical quantities in unitary quantum field theories. Using analyticity of Green functions in a complex scale parameter, the infra-red limit is expressed as a contour integral entirely in the ultra-violet region. The infra-red limit is shown to be the limit of the Borel transform of the phy

Kazuyuki Furuuchi

I carefully study noncommutative version of ADHM construction of instantons, which was proposed by Nekrasov and Schwarz. Noncommutative ${\bf R}^4$ is described as algebra of operators acting in Fock space. In ADHM construction of instantons, one looks for zero-modes of Dirac-like operator. The feature peculiar to noncommutative case is that these zero-modes

ChangSoo Park, D. K. Park

The role of Aharonov-Bohm effect in quantum tunneling is examined when a potential is defined on the $S^1$ and has $N$-fold symmetry. We show that the low-lying energy levels split from the $N$-fold degenerate ground state oscillate as a function of the Aharonov-Bohm phase, from which general degeneracy conditions depending on the magnetic flux is obtained.

Ikuo Ichinose, Keiichi Nagao

We investigate chiral properties of the overlap lattice fermion by using solvable model in two dimensions, the gauged Gross-Neveu model. In this model, the chiral symmetry is spontaneously broken in the presence of small but finite fermion mass. We calculate the quasi-Nambu-Goldstone(NG) boson mass as a function of the bare fermion mass and two parameters in

W. P. S. Meikle

The absolute luminosities and homogeneity of early-time infrared (IR) light curves of type Ia supernovae are examined. Eight supernovae are considered. These are selected to have accurately known epochs of maximum blue light as well as having reliable distance estimates and/or good light curve coverage. Two approaches to extinction correction are considered.

Rodrigo Aros, Mauricio Contreras, Rodrigo Olea, Ricardo Troncoso

Mass and other conserved Noether charges are discussed for solutions of gravity theories with locally Anti-de Sitter asymptotics in 2n dimensions. The action is supplemented with a boundary term whose purpose is to guarantee that it reaches an extremum on the classical solutions, provided the spacetime is locally AdS at the boundary. It is also shown that if

Xiao-Guang Wang, Shao-Hua Pan, Guo-Zhen Yang

Within the framework of mean field theory, we study the effects of multi-surface modification on Curie temperature of ferroelectric films using the transverse Ising model. The general nonlinear equations for Curie temperature of multi-surface ferroelectric films with arbitrary exchange constants and transverse fields are derived by the transfer matrix method

SDSS Collaboration, Fischer

(abridged) We present measurements of galaxy-galaxy lensing from early commissioning imaging data from the Sloan Digital Sky Survey (SDSS). We measure a mean tangential shear around a stacked sample of foreground galaxies in three bandpasses out to angular radii of 600&#39;&#39;, detecting the shear signal at very high statistical significance. The shear pro

C. S. Reynolds, J. Wilms

It has recently been suggested that Compton downscattering may give rise to the broad iron lines seen in the X-ray spectra of Seyfert 1 galaxies. This challenges the standard model in which these lines originate from the innermost regions of the black hole accretion disk with Doppler shifts and gravitational redshifts giving rise to the broadened line profil

S. Bose, V. Vedral

We show that on exceeding a certain degree of mixedness (as quantified by the von Neumann entropy), entangled states become useless for teleporatation. By increasing the dimension of the entangled systems, this entropy threshold can be made arbitrarily close to maximal. This entropy is found to exceed the entropy threshold sufficient to ensure the failure of

Richard L. Hall

Let E = F(v) be the ground-state eigenvalue of the Schroedinger Hamiltonian H = -Delta + vf(x), where the potential shape f(x) is symmetric and monotone increasing for x > 0, and the coupling parameter v is positive. If the &#39;kinetic potential&#39; bar{f}(s) associated with f(x) is defined by the transformation: bar{f}(s) = F&#39;(v), s = F(v)-vF&#39;(v),

Angelo Bassi, GianCarlo Ghirardi

We reconsider the Decoherent Histories approach to Quantum Mechanics and we analyze some problems related to its interpretation which, according to us, have not been adequately clarified by its proponents. We put forward some assumptions which, in our opinion, are necessary for a realistic interpretation of the probabilities that the formalism attaches to de

Marek Zukowski

The quantum teleportation process is composed of a joint measurement performed upon two subsystems A and B (uncorrelated), followed by a unitary transformation (parameters of which depend on the outcome of the measurement) performed upon a third subsystem C (EPR correlated with system B). The information about the outcome of the measurement is transferred by

G. A. Prataviera, J. Zapata, P. Meystre

We use an operational approach to discuss ways to measure the higher-order cross-correlations between optical and matter-wave fields. We pay particular attention to the fact that atomic fields actually consist of composite particles that can easily be separated into their basic constituents by a detection process such as photoionization. In the case of boson

P. V. Elyutin, A. N. Rogovenko

The studied model describes a particle that obeys a one-dimensional nonlinear Schrödinger equation in the potential of a double-well. Transitions between the two lowest self-trapped states of this system under the influence of the external time-dependent perturbation are studied in the two-mode approximation. If the perturbation dependence on time is harmoni

A. Farkas, N. Nicolaevici

We obtain the Casimir effect for the massless scalar field in one dimension based on the analogy between the quantum field and the continuum limit of an infinite set of coupled harmonical oscillators.

Do Minh Chi

We research the natural causality of the Universe. We find that the equation of causality provides very good results on physics. That is our first endeavour and success in describing a quantitative expression of the law of causality. Hence, our theoretical point suggests ideas to build other laws including the law of the Universe&#39;s evolution.

G. Chanfray, D. Davesne, J. Delorme, M. Ericson

This paper is devoted to the evaluation of the pionic scalar density at finite temperature and baryonic density. We express the latter effect in terms of the nuclear response evaluated in the random phase approxima- tion. We discuss the density and temperature evolution of the pionic density which governs the quark condensate evolution. Numerical evalua- tio

Itzhak Tserruya

The most recent results on dileptons obtained in the CERN heavy-ion programme are reviewed.

N. P. Landsman

Quantum groupoids are a joint generalization of groupoids and quantum groups. We propose a definition of a compact quantum groupoid that is based on the theory of C*-algebras and Hilbert bimodules. The essential point is that whenever one has a tensor product over the complex numbers in the theory of quantum groups, one now uses a certain tensor product over

Pieter Moree

Let a,f and g be integers, with a and f coprime. Under the generalized Riemann hypothesis it follows from work of Hooley and Lenstra that the set of primes p such that p=a(mod f) and g is primitive root mod p has a natural density. In this note we explicitly evaluate this density and give some applications of this result.

Valerio Talamanca

In this paper we prove a limit formula for heights on the endomorphism ring of a vector space over a number field. This limit formula can be considered as the analogue for both the Gelfand-Beurling formula for the spectral radius on a Banach Algebra and Tate&#39;s averaging procedure for constructing canonical heights on Abelian Varieties.

Shulim Kaliman

Suppose that X&#39; is a smooth affine algebraic variety of dimension 3 with H_3(X&#39;)=0 which is a UFD and whose invertible functions are constants. Suppose that Z is a Zariski open subset of X which has a morphism p : Z -> U into a curve U such that all fibers of p are isomorphic to C^2. We prove that X&#39; is isomorphic to C^3 iff none of irreducible c

Moussa Balde

Locally, isoperimetric problems on Riemannian surfaces are sub-Riemannian problems in dimension 3. The particular case of Dido problems corresponds to a class of singular contact sub-Riemannian metrics : metrics which have the charateristic vertor field as symmetry. We give a classification of the generic conjugate loci (i.e. classification of generic singul

A. Genestier

Borrowing a reduction principle to a recent preprint of G. Faltings (toroidal resolution of some matrix singularities, 1999), we use Lafforgue&#39;s compactification of PGL_r^{N+1}/PGL_r to construct a canonical log-smooth toroidal resolution for the bad reduction in a prime p of Shimura varieties of unitary and symplectic type with parahoric level structure

Mihai Ciucu, Theresia Eisenkölbl, C. Krattenthaler, D. Zare

We deal with unweighted and weighted enumerations of lozenge tilings of a hexagon with side lengths $a,b+m,c,a+m,b,c+m$, where an equilateral triangle of side length $m$ has been removed from the center. We give closed formulas for the plain enumeration and for a certain $(-1)$-enumeration of these lozenge tilings. In the case that $a=b=c$, we also provide c

Sa&#39;ar Hersonsky, Frederic Paulin

Let M be a geometrically finite pinched negatively curved Riemannian manifold with at least one cusp. We study the asymptotics of the number of geodesics in M starting from and returning to a given cusp, and of the number of horoballs at parabolic fixed points in the universal cover of M. In the appendix, due to K. Belabas, the case of SL(2,Z) and of Bianchi

Roger Alperin

We prove the following version of Milnor&#39;s theorem on solvable groups of exponential growth: A finitely generated solvable group which is not polycyclic contains an ascending HNN extension. Consequently, a finitely generated solvable group is ERF iff it is polycyclic.