July 2000 arXiv papers — page 8
Showing 701–800 of 2,447 papers
B. M. Sabra, J. C. Shields, A. V. Filippenko
Extended nebular filaments are seen at optical wavelengths in NGC 1275, the central galaxy in the Perseus cluster. The agents responsible for the excitation of these filaments remain poorly understood. In this paper we investigate possible mechanisms for powering the filaments, using measurements from an extensive spectroscopic data set acquired at the Lick
William B. Sparks, Stefi A. Baum, John Biretta, F. Duccio Macchetto
The presence of optical synchrotron jets in radio galaxies is relatively rare. Here, we show that of the nearest five FR-I 3CR radio galaxies showing optical jets, {\it four} show evidence for almost circular, presumably face-on, dust disks. This is strong support for the two-fold idea that (\romannumeral1) jets emerge close to perpendicular to inner gas dis
E. C. Moran, A. J. Barth, L. E. Kay, A. V. Filippenko
We have discovered polarized broad emission lines in five type 2 Seyfert galaxies (NGC 424, NGC 591, NGC 2273, NGC 3081, and NGC 4507), establishing that these objects are type 1 Seyferts obscured by dense circumnuclear material. The galaxies are part of a distance-limited sample of 31 Seyfert 2s, for which spectropolarimetric observations are now complete.
K. Nandra
Iron K-alpha lines are key diagnostics of the central regions of AGN. Their profiles indicate that they are formed deep in the potential well of the central black hole, where extreme broadening and red shift occur. The profiles are most easily reproducible in an accretion disk: the lack of significant emission blue-ward of the rest energy is difficult produc
Niranjan Sambhus, S. Sridhar
We investigate the orbital structure of a model triaxial star cluster, centered around a supermassive black hole (BH), appropriate to galactic nuclei. Sridhar and Touma (1999) proved that the presence of the BH enforces some regularity in the dynamics within the radius of influence of the BH. We employ their averaging method to reduce the degrees of freedom
Li-Xin Li
A new scenario for extracting energy from a Kerr black hole is proposed. With magnetic field lines connecting plasma particles inside the ergosphere with remote loads, the frame dragging twists the field lines so that energy and angular momentum are extracted from the plasma particles. If the magnetic field is strong enough, the energy extracted from the par
Roy Maartens
Magnetic fields are observed not only in stars, but in galaxies, clusters, and even high redshift Lyman-alpha systems. In principle, these fields could play an important role in structure formation and also affect the anisotropies in the cosmic microwave background radiation (CMB). The study of cosmological magnetic fields aims not only to quantify these eff
B. Stelzer, R. Neuhaeuser
We report on X-ray emission from members of the recently discovered Tucanae association, a group of stars with youth signatures and similar space motion. The Tucanae association is the nearest known region of recent star formation (at 45 pc) far from molecular clouds. We have made use of the ROSAT Data Archive, and searched for X-rays from Tucanae stars in b
B. Mookerjea, S. K. Ghosh, T. N. Rengarajan, S. N. Tandon
Large scale far-infrared (FIR) observations of the Orion complex at 205 and 138 micron are presented with an aim of studying the distribution of cold (< 25 K) dust. The maps in these FIR bands extend over approximately 3600 sq. arcmin and cover regions around OMC-1, 2, 3 in Orion A and NGC 2023 and NGC 2024 in Orion B. Some limited regions have also been map
A simluated TCDM cosmology cluster catalogue: the NFW profile and the temperature-mass scaling relations
astro-phP. A. Thomas, O. Muanwong, F. R. Pearce, H. M. P. Couchman
We have extracted over 400 clusters, covering more than 2 decades in mass, from three simulations of the TCDM cosmology. This represents the largest, uniform catalogue of simulated clusters ever produced. The clusters exhibit a wide variety of density-profiles. Only a minority are well-fit in their outer regions by the widely used density profile of Navarro,
S. Frey, L. I. Gurvits, D. R. Altschuler, M. M. Davis
AO 0235+164 is a very compact, flat spectrum radio source identified as a BL Lac object at a redshift of z=0.94. It is one of the most violently variable extragalactic objects at both optical and radio wavelengths. The radio structure of the source revealed by various ground-based VLBI observations is dominated by a nearly unresolved compact component at alm
B. Lefloch, J. Cernicharo
The Trifid nebula is a young HII region undergoing a burst of star formation. In this article, we report on far-infrared and millimeter continuum and line observations of several massive and bright protostellar sources in the vicinity of the exciting star fo the nebula, just behind the ionization front. These objects are probably young protostars (Class 0) a
F. Frontera, N. Masetti, M. Orlandini, L. Amati
We report on results of BeppoSAX Target Of Opportunity (TOO) observations of the source MXB 1730-335, also called the Rapid Burster (RB), made during its outburst of February-March 1998. We monitored the evolution of the spectral properties of the RB from the outburst decay to quiescence. During the first TOO, the X-ray light curve of the RB showed many Type
Induced Scattering and Two-Photon Absorption of Alfven Waves with Arbitrary Propagation Angles
astro-phV. N. Zirakashvili
The equation for temporary evolution of spectral energy of collisionless Alfven waves is derived in framework of weak turbulence theory. The main nonlinear processes for such conditions are induced scattering and two quantum absorption of Alfven waves by thermal ions. The equation for velocity distribution of thermal particles is derived that describes diffu
Horst R. Beyer
The paper provides a new framework for the description of linearized adiabatic lagrangian perturbations and stability of differentially rotating newtonian stars. In doing so it overcomes problems in a previous framework by Dyson and Schutz and provides the basis of a rigorous analysis of the stability of such stars. For this the governing equation of the osc
J. Liske
We discuss the problem of how to calculate the distance between two cosmological objects given their redshifts and angular separation on the sky. Although of a fundamental nature, this problem and its solution seem to lack a detailed description in the literature. We present a new variant of its solution and quantitatively assess the most commonly used appro
Cosmological Density Perturbations in two fluid models on spin dominated inflation and the stability of Friedmann metric
astro-phL. C. Garcia de Andrade
A spinning fluid embedded in a space section flat Friedmann model is used to compute the cosmological density perturbation of the model.The spinning fluid obeys the Einstein-Cartan field equations while the Friedmann embedded model is assumed to obey the general the Friedmann equation in General Relativity.It is shown that at the early epochs of the Universe
P. Yock, I. Bond, N. Rattenbury, J. Skuljan
Recent work by the MOA gravitational microlensing group is briefly described, including (i) the current observing strategy, (ii) use of a high-speed parallel computer for analysis of results by inverse ray shooting, (iii) analysis of the light curve of event OGLE-2000-BUL12 in terms of extra-solar planets, and (iv) the MOA alert system using difference imagi
Farinaz Roshani, Mohammad Khorrami
A family of diffusion-annihilation processes is introduced, which is exactly solvable. This family contains parameters that control the diffusion- and annihilation- rates. The solution is based on the Bethe ansatz and using special boundary conditions to represent the reaction. The processes are investigated, both on the lattice and on the continuum. Special
J. W. Moffat
The possible role of gravity in a noncommutative geometry is investigated. Due to the Moyal *-product of fields in noncommutative geometry, it is necessary to complexify the metric tensor of gravity. We first consider the possibility of a complex Hermitian, nonsymmetric $g_{μν}$ and discuss the problems associated with such a theory. We then introduce a comp
Alexander Kusenko, Marieke Postma
Some of the proposed explanations for the origin of ultrahigh-energy cosmic rays invoke new sources of energetic photons (e.g., topological defects, relic particles, etc.). At high red shift, when the cosmic microwave background has a higher temperature but the radio background is low, the ultrahigh-energy photons can generate neutrinos through pair-producti
Karl Millar, Washington Taylor, Mark Van Raamsdonk
We study the polarization states of the D0-brane in type IIA string theory. In addition to states with angular momentum and magnetic dipole moments, there are polarization states of a single D0-brane with nonzero D2-brane dipole and magnetic H-dipole moments, as well as quadrupole and higher moments of various charges. These fundamental moments of the D0-bra
P. Levai, T. S. Biro, T. Csorgo, J. Zimanyi
We study the production of charmed hadrons with the help of ALCOR_c, the algebraic coalescence model for rehadronisation of charmed quark matter. Mesonic ratios are introduced as factors connecting various antibaryon to baryon ratios. The resulting simple relations could serve as tests of quark matter formation and coalescence type rehadronization in heavy i
Tamath Rainsford
In this paper we explore how far the post-Newtonian theory goes in overcoming the difficulties associated with anisotropic homogeneous cosmologies in the Newtonian approximation. It will be shown that, unlike in the Newtonian case, the cosmological equations of the post-Newtonian approximation are much more in the spirit of general relativity with regard to
Lei-Han Tang, Hugues Chaté
Sequence heterogeneity broadens the binding transition of a polymer onto a linear or planar substrate. This effect is analyzed in a real-space renormalization group scheme designed to capture the statistics of rare events. In the strongly disordered regime, binding initiates at an exponentially rare set of ``good contacts''. Renormalization of the co
Max Bonamente, Richard Lieu, Jonathan P. D. Mittaz
The discovery of EUV and soft X-ray excess emission in clusters of galaxies (the cluster soft-excess phenomenon) challenged the notion of the hot ($\sim 10^{7-8}$ K) gas as the only dominant thermal component of the intracluster medium (ICM). The spatial analysis of ROSAT PSPC 1/4 keV images presented here reveals compelling evidence for substantial amounts
A. H. Jaffe, P. A. R. Ade, A. Balbi, J. J Bock
Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE-DMR, provide consistent and high signal-to-noise measurements of the CMB power spectrum at spherical harmonic multipole bands over $2<\ell\lta800$. Analysis of the combined data yields 68% (95%) confidence limits on the total density, $Ω_{\rm {tot}}\simeq 1.11 \pm 0.07 (^{+0.13}_{-0.12})
Ph. de Forcrand, M. D'Elia, M. Pepe
We study the behaviour of the spatial and temporal 't Hooft loop at zero and finite temperature in the 4D SU(2) Yang-Mills theory, using a new numerical method. In the deconfined phase $T>T_c$, the spatial 't Hooft loop exhibits a dual string tension, which vanishes at $T_c$ with 3D Ising-like critical exponent.
Lester Ingber, Radu Paul Mondescu
We describe an end-to-end real-time S&P futures trading system. Inner-shell stochastic nonlinear dynamic models are developed, and Canonical Momenta Indicators (CMI) are derived from a fitted Lagrangian used by outer-shell trading models dependent on these indicators. Recursive and adaptive optimization using Adaptive Simulated Annealing (ASA) is used for fi
Armando Babiano, Julyan H. E. Cartwright, Oreste Piro, Antonello Provenzale
We show that, even in the most favorable case, the motion of a small spherical tracer suspended in a fluid of the same density may differ from the corresponding motion of an ideal passive particle. We demonstrate furthermore how its dynamics may be applied to target trajectories in Hamiltonian systems.
Emergent global oscillations in heterogeneous excitable media: The example of pancreatic beta cells
nlin.CDJulyan H. E. Cartwright
Using the standard van der Pol-FitzHugh-Nagumo excitable medium model I demonstrate a novel generic mechanism, diversity, that provokes the emergence of global oscillations from individually quiescent elements in heterogeneous excitable media. This mechanism may be operating in the mammalian pancreas, where excitable beta cells, quiescent when isolated, are
Julyan H. E. Cartwright
I propose that stiffness may be defined and quantified for nonlinear systems using Lyapunov exponents, and demonstrate the relationship that exists between stiffness and the fractal dimension of a strange attractor: that stiff chaos is thin chaos.
O. Calvo, J. H. E. Cartwright, D. L. Gonzalez, O. Piro
We investigate numerically and experimentally dynamical systems having three interacting frequencies: a discrete mapping (a circle map), an exactly solvable model (a system of coupled ordinary differential equations), and an experimental device (an electronic oscillator). We compare the hierarchies of three-frequency resonances we find in each of these syste
Shoji Okumura
We study the anti-self-dual equation for non-diagonal SU(2)-invariant metrics and give an equivalent ninth-order system. This system reduce to a sixth-order system if the metric is in the conformal class of scalar-flat-Kaehler metric.
Edge Effects on Local Statistics in Lattice Dimers: A Study of the Aztec Diamond (Finite Case)
math.COHarald Helfgott
We compute the probability of any local pattern at an arbitrary position in a random dimer configuration in a square grid with an Aztec-diamond boundary.
Edward Goldstein
In this paper we use structure preserving torus actions on Kahler-Einstein manifolds to construct minimal Lagrangian submanifolds. Our main result is: Let N^2n be a Kahler-Einstein manifold with positive scalar curvature with an effective T^n-action. Then precisely one regular orbit L of the T-action is a minimal Lagrangian submanifold of N. Moreover there i
Manfredi Maggiore, Kevin Passino
This paper introduces a new approach for output feedback stabilization of SISO systems which, unlike most of the techniques found in the literature, does not use high-gain observers and control input saturation to achieve separation between the state feedback and observer designs. Rather, we show that by using nonlinear observers, together with a projection
Green's Functions in Axial and Lorentz-type Gauges and Application to The Axial Pole Prescription and The Wilson Loop
hep-thSatish D. Joglekar
We summarize the work done in connecting Green's functions in a different classes of gauges and its applications to the problems in the axial gauges.The procedure adopted uses finite field-dependent BRS [FFBRS] transformations to connect axial and the Lorentz type gauges.These transformations preserve the vacuum expectation of gauge-invariant observables
M. Alimohammadi, Kh. Saaidi
By generalizing the auxiliary field term in the Lagrangian of simplicial chiral models on a (d-1)-dimensional simplex, the generalized simplicial chiral models has been introduced in \c{Ali}. These models can be solved analytically only in d=0 and d=2 cases at large-N limit. In d=0 case, we calculate the eigenvalue density function in strong regime and show
Measurements of the $Q^2$-Dependence of the Proton and Neutron Spin Structure Functions g1p and g1n
hep-phThe E155 Collaboration, P. L. Anthony
The structure functions g1p and g1n have been measured over the range 0.014 < x < 0.9 and 1 < Q2 < 40 GeV2 using deep-inelastic scattering of 48 GeV longitudinally polarized electrons from polarized protons and deuterons. We find that the Q2 dependence of g1p (g1n) at fixed x is very similar to that of the spin-averaged structure function F1p (F1n). From a N
Hirotaka Ochiai, Katsuhiko Sato
In the framework of the Hartle-Hawking no-boundary proposal, we investigate quantum creation of the multidimensional universe with the cosmological constant $Λ$ but without matter fields. In this paper we solved the Wheeler-de Witt equation numerically. We find that the universe in which both of the spaces expand exponentially is the most probable in this mo
Hirotaka Ochiai, Katsuhiko Sato
In the framework of the Hartle-Hawking no-boundary proposal, we investigated quantum creation of the multidimensional universe with a cosmological constant ($Λ$) but without matter fields. We have found that the classical solutions of the Euclidean Einstein equations in this model have ``quasi-attractors'', i.e., most trajectories on the a-b plane, w
S. L. Sondhi, Kun Yang
We show that three dimensional "sliding" analogs of the Kosterlitz-Thouless phase, in stacked classical two-dimensional XY models and quantum systems of coupled Luttinger Liquids, can be enlarged by the application of a parallel magnetic field, which has the effect of increasing the scaling dimensions of the most relevant operators that can perturb t
J. Gonzalez
The charge instabilities of electron systems in the square lattice are analyzed near the Van Hove singularity by means of a wilsonian renormalization group approach. We show that the method preserves the spin rotational invariance at all scales, allowing a rigorous determination of spin and charge instabilities of the $t-t'$ Hubbard model. For $t'$ a
Giorgio Parisi
In this talk I will introduce the principle of stochastic stability and discussing its consequences both at equilibrium and off-equilibrium.
V. Celebonovic, W. Dappen
Using a simple criterion proposed by Kirzhnitz,we have discussed the plasma-solid transition in two simple model cases: the Fermi-Dirac and Bose Einstein gas.Some possibilities of astrophysical applications of our results are also indicated.
Douglas C. Heggie
We consider both observational and theoretical issues related to dynamical mass loss from the old globular star clusters of the Galaxy. On the observational side the evidence includes tidal tails and extratidal extensions, kinematic effects, effects on the mass function, and influences on the statistical properties of surviving objects. Even for isolated clu
Maciej Konacki, Andrzej J. Maciejewski, Alex Wolszczan
We present a new analysis of the dynamics of the planetary system around the pulsar B1257+12. A semi-analytical theory of perturbation between terrestrial-mass planets B and C is developed and applied to improve multi-orbit timing formula for this object. We use numerical simulations of the pulse arrival times for PSR B1257+12 to demonstrate that our new tim
D. T. Frayer
I discuss our ongoing Owens Valley Millimeter Array observations and Keck near-infrared wavelength observations of the high-redshift sub-mm population of galaxies. These observations are important for our understanding of the distant universe since the sub-mm population accounts for a large fraction of the extragalactic background at mm/sub-mm wavelengths an
Clifford V. Johnson
Following is a collection of lecture notes on D-branes, which may be used by the reader as preparation for applications to modern research applications such as: the AdS/CFT and other gauge theory/geometry correspondences, Matrix Theory and stringy non-commutative geometry, etc. In attempting to be reasonably self-contained, the notes start from classical poi
Superconductivity from Undressing. II. Single Particle Green's Function and Photoemission in Cuprates
cond-mat.supr-conJ. E. Hirsch
Experimental evidence indicates that the superconducting transition in high $T_c$ cuprates is an 'undressing' transition. Microscopic mechanisms giving rise to this physics were discussed in the first paper of this series. Here we discuss the calculation of the single particle Green's function and spectral function for Hamiltonians describing und
Alan Chodos, Fred Cooper, Anupam Singh, Wenjin Mao
We study the dynamics of the chiral phase transition at finite chemical potential in the Gross-Neveu model in the leading order in large-N approximation. We consider evolutions starting in local thermal equilibrium in the massless unbroken phase for conditions pertaining to traversing a first or second order phase transition. We assume boost invariant kinema
J. Alvarez-Muniz, F. Halzen
We show that a kilometer-scale neutrino observatory, though optimized for TeV to PeV energy, is sensitive to the neutrinos associated with super-EeV sources. These include super-heavy relics, neutrinos associated with the Greisen cutoff, and topological defects which are remnant cosmic structures associated with phase transitions in grand unified gauge theor
S. F. King, N. Nimai Singh
We study models of neutrino masses which naturally give rise to an inverted mass hierarchy and bi-maximal mixing. The models are based on the see-saw mechanism with three right-handed neutrinos, which generates a single mass term of the form $ν_e(ν_μ+ν_τ)$ corresponding to two degenerate neutrinos $ν_e$ and $ν_μ+ν_τ$, and one massless neutrino $ν_μ-ν_τ$. Atm
Jozef H. Przytycki, Adam S. Sikora
L. Kauffman conjectured that a particular solution of the Chinese Rings puzzle is the simplest possible. We prove his conjecture by using low-dimensional topology and group theory. We notice also a surprising connection between the Chinese Rings and Habiro moves (related to Vassiliev invariants).
Satellite non-gravitational orbital perturbations and the detection of the gravitomagnetic clock effect
gr-qcLorenzo Iorio
The general relativistic gravitomagnetic clock effect consists in the fact that two massive test bodies orbiting a central spinning mass in its equatorial plane along two identical circular trajectories, but in opposite directions, take different times in describing a full revolution with respect to an asymptotically inertial observer. In the field of the Ea
Gautam Bhattacharyya, Darwin Chang, Chung-Hsien Chou, Wai-Yee Keung
We demonstrate that the R-parity breaking interactions within their current experimental upper bounds can give rise to large mixing-induced CP asymmetry in exclusive radiative B decays that may be detectable in the upcoming B factories.
Marcello Ciafaloni, Dimitri Colferai, Gavin P. Salam
We investigate factorisation at small x using a variety of analytical and numerical techniques. Previous results on factorisation in collinear models are generalised to the case of the full BFKL equation, and illustrated in the example of a collinear model which includes higher twist terms. Unlike the simplest collinear model, the BFKL equation leads to effe
Peter Bowcock, Christos Charmousis, Ruth Gregory
Starting from a completely general standpoint, we find the most general brane-Universe solutions for a three-brane in a five dimensional spacetime. The brane can border regions of spacetime with or without a cosmological constant. Making no assumptions other than the usual cosmological symmetries of the metric, we prove that the equations of motion form an i
V. Pasquier
It has been recently shown that solitons are fundamental classical solutions of non-commutative field theories. We reconsider this issue from the standpoint of the Hall effect and identify some solutions with known solutions in the integer Hall effect with no Zeeman coupling.
Michael Creutz
I explore the non-perturbative issues entwining lattice gauge theory, anomalies, and chiral symmetry. After briefly reviewing the importance of chiral symmetry in particle physics, I discuss how anomalies complicate lattice formulations. Considerable information can be deduced from effective chiral Lagrangians, helping interpret the expectations for lattice
Thermal relaxation in charge ordered Pr$_{0.63}$ Ca$_{0.37}$ MnO$_3$ in presence of a magnetic field
cond-mat.str-elA. K. Raychaudhuri, Ayan Guha, I. Das, R. Rawat
We report observation of substantial thermal relaxation in single crystal of charge ordered system Pr$_{0.63}$Ca$_{0.37}$MnO$_3$ in an applied magnetic field of H = 8T. The relaxation is observed when the temperature is scanned in presence of a magnetic field in the temperature interval $T_{MH}<T<T_{CO}$ where $T_{CO}$ is the charge ordering temperature and
J. Fuchs, L. R. Huiszoon, A. N. Schellekens, C. Schweigert
Universal formulas for the boundary and crosscap coefficients are presented, which are valid for all symmetric simple current modifications of the charge conjugation invariant of any rational conformal field theory.
Yang Ji, M. Heiblum, D. Sprinzak, D. Mahalu
The coherence and phase evolution of electrons in a mesoscopic system in the Kondo correlated regime were studied. The Kondo effect, in turn, is one of the most fundamental many-body effects where a localized spin interacts with conduction electrons in a conductor. Results were obtained by embedding a quantum dot (QD) in a double path electronic interferomet
T. S. Sinegovskaya, S. I. Sinegovsky
We present high energy spectra and zenith-angle distributions of the atmospheric muons computed for the depths of the locations of the underwater neutrino telescopes. We compare the calculations with the data obtained in the Baikal and the AMANDA muon experiments. The prompt muon contribution to the muon flux underwater due to recent perturbative QCD-based m
J. Eisert, H. -J. Briegel
We present a measure of quantum entanglement which is capable of quantifying the degree of entanglement of a multi-partite quantum system. This measure, which is based on a generalization of the Schmidt rank of a pure state, is defined on the full state space and is shown to be an entanglement monotone, that is, it cannot increase under local quantum operati
P. Astone, M. Bassan, P. Bonifazi, P. Carelli
Coincidences are searched with the cryogenic resonant gravitational wave detectors EXPLORER and NAUTILUS, during a period of about six months (2 June-14 December 1998) for a total measuring time of 94.5 days, with the purpose to study new algorithms of analysis, based on the physical characteristics of the detectors.
O. P. Sushkov, J. Oitmaa, Zheng Weihong
We analyze the phase diagram of the frustrated Heisenberg antiferromagnet, the J1-J2 model, in two dimensions. Two quantum phase transitions in the model are already known: the second order transition from the Neel state to the spin liquid state at (J_2/J_1)_{c2}=0.38, and the first order transition from the spin liquid state to the collinear state at (J_2/J
Donald Marolf
Two subtle aspects of brane intersections are investigated. The first concerns the `half-branes' that arise in discussions of the Hanany-Witten effect, often in the D0/D8 setting. The second involves the validity of seemingly singular classical BPS brane intersections. A study of holomorphic curves in the background of a Kaluza-Klein monopole and the ass
Robert L. Bryant
A second order family of special Lagrangian submanifolds of complex m-space is a family characterized by the satisfaction of a set of pointwise conditions on the second fundamental form. For example, the set of ruled special Lagrangian submanifolds of complex 3-space is characterized by a single algebraic equation on the second fundamental form. While the `g
C. Henkel, S. Potting
A transport theory for atomic matter waves in low-dimensional waveguides is outlined. The thermal fluctuation spectrum of magnetic near fields leaking out of metallic microstructures is estimated. The corresponding scattering rate for paramagnetic atoms turns out to be quite large in micrometer-sized waveguides (approx. 100/s). Analytical estimates for the h
A. Beige, S. Bose, D. Braun, S. F. Huelga
Quantum information processing rests on our ability to manipulate quantum superpositions through coherent unitary transformations, and to establish entanglement between constituent quantum components of the processor. The quantum information processor (a linear ion trap, or a cavity confining the radiation field for example) exists in a dissipative environme
Cs. Benedek, M. G. Benedict, T. Serenyi
Instead of using frequency dependent refractive index, we propose to use the extinction theorem to describe reflection and transmission of an ultrashort pulse passing through the boundary. When the duration of the pulse is comparable with the relaxation time, the results differ significantly from those given by the traditional method, especially if the carri
Hiraku Nishimori, Hirohisa Tanaka
A simple model for the dynamics of dunes associated with vegetation is proposed. Using the model, formation processes of transverse dunes, parabolic dunes and elongated parabolic dunes according to two environmental factors: i)the amount of sand at the source, ii)the wind force, are simulated. The results have qualitative correspondence to the real counterpa
C. P. Dettmann, E. G. D. Cohen
We investigate the connections between microscopic chaos, defined on a dynamical level and arising from collisions between molecules, and diffusion, characterized by a mean square displacement proportional to the time. We use a number of models involving a single particle moving in two dimensions and colliding with fixed scatterers. We find that a number of
Y. Polatoglu, M. Bolcal
The purpose of this paper is to give exact value of the radius of starlikeness and distortion theorem, Koebe domain for the class of Janowski's starlike functions of complex order. We note that the class of Janowski's starlike functions of complex order contain many interesting subclasses of univalent functions.
Christian Baer
The theme is the influence of the spin structure on the Dirac spectrum of a spin manifold. We survey examples and results related to this question.
Denis Auroux
After reviewing recent results on symplectic Lefschetz pencils and symplectic branched covers of CP^2, we describe a new construction of maps from symplectic manifolds of any dimension to CP^2 and the associated monodromy invariants. We also show that a dimensional induction process makes it possible to describe any compact symplectic manifold by a series of
Pierre Albarede
Using game and probability theories, I study the French popular game 421, a perfect information stochastic stage game. The problem is to find strategies maximizing the probability of some expected utility. I only solve a player's round against providence, a problem of fate stochastic management: beyond the backward induction solution, bounded complexity
Emmanuel Ferrand
It is proved in this note that the analogues of the Bennequin inequality which provide an upper bound for the Bennequin invariant of a Legendrian knot in the standard contact three dimensional space in terms of the lower degree in the framing variable of the HOMFLY and the Kauffman polynomials are not sharp. Furthermore, the relationships between these restr
Edward Witten
K-theory provides a framework for classifying Ramond-Ramond (RR) charges and fields. K-theory of manifolds has a natural extension to K-theory of noncommutative algebras, such as the algebra considered in noncommutative Yang-Mills theory or in open string field theory. In a number of concrete problems, the K-theory analysis proceeds most naturally if one sta
Angel M. Uranga
Recent scenarios of phenomenologically realistic string compactifications involve the existence of gauge sectors localized on D-branes at singular points of Calabi-Yau threefolds. The spectrum and interactions in these gauge sectors are determined by the local geometry of the singularity, and can be encoded in quiver diagrams. We discuss the physical models
Maja Buric, Voja Radovanovic
In this paper we analyse the quantum correction for Schwarzschild black hole in the Unruh state in the framework of spherically symmetric gravity (SSG) model. SSG is a two-dimensional dilaton model which is obtained by spherically symmetric reduction from the four-dimensional theory. We find the one-loop geometry of the (anti)-evaporating black hole and corr
Luca Mezincescu
We outline the description of Quantum Mechanics with noncommuting coordinates within the framework of star operation. We discuss simple cases of integrability.
Konstantin G. Savvidy
In this note we obtain the discrete spectrum of the rotating ellipsoidal membrane, the solution to classical equations of motion in the matrix mechanics of N D0-branes. This solution has the interpretation of a closed D2-brane with the D0-branes bound to its surface. The semi-classical quantization is performed on the rotational modes with the result that bo
A. Denner, S. Dittmaier, M. Roth, D. Wackeroth
We present precise predictions for the processes e+ e- -> WW -> 4f(gamma) at LEP2 and future Linear-Collider (LC) energies obtained with the Monte Carlo generator RacoonWW. The program RacoonWW includes the complete O(alpha) electroweak radiative corrections to e+ e- -> WW -> 4f in the double-pole approximation (DPA). While the virtual corrections are treate
M. A. Braun, C. Pajares, V. V. Vechernin
It is demonstrated that in a two-stage scenario with elementary Poissonian emitters of particles (colour strings) arbitrarily distributed in their number and average multiplicities, the forward- backward correlations are completely determined by the final distribution of the forward particles. The observed linear form of the correlations then necessarily req
G. M. Shore
The gauge invariant operator formulation of the angular momentum sum rule ${1\over2} = J_q + J_g$ for the proton is presented and contrasted with the sum rule for the first moment of the polarised structure function $g_1^p$. The decoupling of the axial charge $a^0$ from the angular momentum sum rule is highlighted and the possible QCD field-theoretic basis f
Comparison of $k_T$-Factorization Approach and QCD Parton Model for Charm and Beauty Hadroproduction
hep-phM. G. Ryskin, Yu. M. Shabelski, A. G. Shuvaev
We compare the numerical predictions for heavy quark production in high energy hadron collisions of the conventional QCD parton model and the $k_T$-factorization approach (semihard theory). The total production cross sections, one-particle rapidity and $p_T$ distributions as well as two-particle correlations are considered. The difference in the predictions
K. Matsuda, N. Takeda, T. Fukuyama, H. Nishiura
We illustrate the graphical method that gives the constraints on the parameters appearing in the neutrino oscillation experiments and the neutrinoless double beta decay. This method is applicable in three and four generations. Though this method is valid for more general case, we examine explicitly the cases in which the CP violating factors take $\pm 1$ or
A. Capella, C. A. Salgado
We review the two sources of hyperon enhancement in the dual parton model: strings originating from diquark-antidiquark pairs in the nucleon sea and net baryons containing two or three sea quarks with a yield controlled by the observed stopping. We show that adding final state interactions (including strangeness exchange reactions as well as the inverse reac
X. -J. Wang, M. -L. Yan
We illustrate that both of massless pseudoscalar meson fields and constitutent quark fields are dynamical field degrees of freedom in energy region between chiral symmetry spontaneously broken scale and quark confinement scale. This physical configuration yields a renormalization running axial coupling constant $g_{_A}(μ)$. The one-loop renormalization predi
Quark Mass Matrices with Four and Five Texture Zeroes, and the CKM Matrix, in terms of Mass Eigenvalues
hep-phBipin R. Desai, Alexander R. Vaucher
Using the triangular matrix techniques of Kuo et al and Chiu et al for the four and five texture zero cases, with vanishing (11) elements for U and D matrices, it is shown, from the general eigenvalue equations and hierarchy conditions, that the quark mass matrices, and the CKM matrix can be expressed (except for the phases) entirely in terms of quark masses
Marc Vanderhaeghen
A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities of the nucleon. The real Compton scattering at large momentum transfer is discussed which is asymptotically a
Adil Belhaj
We present the basic ideas of geometric engineering of the supersymmetric quantum field theories viewed as a low energy limit of type II strings and F-theory on singular Calabi Yau manifolds. We first give the main lines of toric geometry as it is a powerful technique to deal compact complex manifolds. Then we introduce mirror symmetry which plays a crucial
C. J. Hamer, M. Samaras, R. J. Bursill
A 'forward walking' Green's Function Monte Carlo algorithm is used to obtain expectation values for SU(3) lattice Yang-Mills theory in (3+1) dimensions. The ground state energy and Wilson loops are calculated, and the finite-size scaling behaviour is explored. Crude estimates of the string tension are derived, which agree with previous results at
Studies of the Response of the Prototype CMS Hadron Calorimeter, Including Magnetic Field Effects, to Pion, Electron, and Muon Beams
hep-exV. V. Abramov, B. S. Acharya, N. Akchurin, I. Atanasov
We report on the response of a prototype CMS hadron calorimeter module to charged particle beams of pions, muons, and electrons with momenta up to 375 GeV/c. The data were taken at the H2 and H4 beamlines at CERN in 1995 and 1996. The prototype sampling calorimeter used copper absorber plates and scintillator tiles with wavelength shifting fibers for readout
A. G. Agnese, M. La Camera
We introduce, by means of the Brans-Dicke scalar field, space-time fluctuations at scale comparable to Planck length near the event horizon of a black hole and examine their dramatic effects.
S. Manoff
The Lagrangian formalism for tensor fields over differentiable manifolds with contravariant and covariant affine connections (whose components differ not only by sign) and metrics [$(\bar{L}_n,g)$-spaces] is considered. The functional variation and the Lie variation of a Lagrangian density, depending on components of tensor fields (with finite rank) and thei
Stuart Samuel
The question of a phase transition in exiting the Planck epoch of the early universe is addressed. An order parameter is proposed to help decide the issue, and estimates are made concerning its behavior. Our analysis is suggestive that a phase transition occurred.