January 1996 arXiv papers — page 11

Adel Bilal

These are notes from introductory lectures given at the Ecole Normale in Paris and at the Strasbourg meeting dedicated to the memory of Claude Itzykson. I review in considerable detail and in a hopefully pedagogical way the work of Seiberg and Witten on $N=2$ supersymmetric $SU(2)$ gauge theory without extra matter. This presentation basically follows their

Giampiero Esposito, Alexander Yu. Kamenshchik, Giuseppe Pollifrone

This paper applies $ζ$-function regularization to evaluate the 1-loop effective action for scalar field theories and Euclidean Maxwell theory in the presence of boundaries. After a comparison of two techniques developed in the recent literature, vacuum Maxwell theory is studied and the contribution of all perturbative modes to $ζ'(0)$ is derived: transve

M. A. Soloviev

We show that a considerable part of the theory of (ultra)distributions and hyperfunctions can be extended to more singular generalized functions, starting from an angular localizability notion introduced previously. Such an extension is needed to treat gauge quantum field theories with indefinite metric in a generic covariant gauge. Prime attention is paid t

J. Lopez

The physics of supersymmetry is reviewed from the perspective of physics at ever increasing energies. Starting from the minimal supersymmetric extension of the Standard Model at the electroweak scale, we proceed to higher energies seeking to understand the origin of the many model parameters. Supersymmetric grand unification, supergravity, and superstrings a

Rolf Dahm

A classification of hadrons and their interactions at low energies according to SU(4) allows to identify combinations of the fifteen mesons $π$, $ω$ and $ρ$ within the spin-isospin decomposition of the regular representation \rhdmulti{15}. Chirally symmetric SU(2)$\times$SU(2) hadron interactions are then associated with transformations of a subgroup of SU(4

C. R. Munz

We present a relativistic calculation of two-photon decays for heavy and light mesons in the framework of the Salpeter equation for quark-antiquark states. The meson-photon-photon vertex is computed by reconstructing the Bethe-Salpeter vertex function and evaluating the four-dimensional Feynman diagram with off-shell quark amplitudes. The two-photon width fo

Jean-Paul Blaizot, Edmond Iancu

The calculation of the lifetime of quasiparticles in a QED plasma at high temperature remains plagued with infrared divergences, even after one has taken into account the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of very soft, unscreened, magnetic photons, whose contribution is e

Andrei Linde, Dmitri Linde, Arthur Mezhlumian

We investigate the distribution of energy density in a stationary self-reproducing inflationary universe. We show that the main fraction of volume of the universe in a state with a given density at any given moment of proper time t is concentrated near the centers of deep exponentially wide spherically symmetric wells in the density distribution. Since this

Maximo Banados, Ricardo Troncoso, Jorge Zanelli

A Chern-Simons action for supergravity in odd-dimensional spacetimes is proposed. For all odd dimensions, the local symmetry group is a non trivial supersymmetric extension of the Poincaré group. In $2+1$ dimensions the gauge group reduces to super-Poincaré, while for $D=5$ it is super-Poincaré with a central charge. In general, the extension is obtained by

H. C. Lee

In this note we study the electron spectral weight of doped Mott insulators based on the 2D slave boson gauge field theory. The vertex correction with static gauge field is calculated in the second order perturbation theory. The vertex correction is found to be singular at low energy and requires non-perturbative treatments.

K. Lin, R. L. Jaffe

We study the solutions to the wave equation in a two-dimensional tube of unit width comprised of two straight regions connected by a region of constant curvature. We introduce a numerical method which permits high accuracy at high curvature. We determine the bound state energies as well as the transmission and reflection matrices, ${\cal T}$ and ${\cal R}$ a

Victor L'vov, Evgenii Podivilov, Itamar Procaccia

It is shown that the generalization of the Navier-Stokes equations to a theory with $N$ ``internal state" copies of the velocity fields is a step in a wrong direction: the $N\to\infty$ limit has no physical sense and produces wrong results, whereas the treatment of the first order terms in $1/N$ is even more complicated than the initial problem of descri

Daniel Segel, Victor L'vov, Itamar Procaccia

In turbulent flows the $n$'th order structure functions $S_n(R)$ scale like $R^{ζ_n}$ when $R$ is in the "inertial range". Extended Self-Similarity refers to the substantial increase in the range of power law behaviour of $S_n(R)$ when they are plotted as a function of $S_2(R)$ or $S_3(R)$. In this Letter we demonstrate this phenomenon analytical

Victor L'vov, Evgenii Podivilov, Itamar Procaccia

It is shown that the description of anomalous scaling in turbulent systems requires the simultaneous use of two normalization scales. This phenomenon stems from the existence of two independent (infinite) sets of anomalous scaling exponents that appear in leading order, one set due to infrared anomalies, and the other due to ultraviolet anomalies. To expose

I. V. Artemova, G. S. Bisnovatyi-Kogan, G. Bjornsson, I. Novikov

We present solutions to the accretion disk structure equations in which advective cooling is accounted for in a self-consistent way. It is shown that for high rates of accretion, above a critical value, when without advection there are no solutions extending continuously from large to small radii, there exist global solutions with self-consistent advective c

R. Staubert, M. Maisack

We report the detection of the bright radio quiet quasar PG 1416-129 by the OSSE instrument on the Compton Gamma Ray Observatory (CGRO). This object had the hardest spectral index of all known AGN in the energy range 2-20 keV (Gamma=1.1 +- 0.1) when observed by Ginga. We find that the source is variable at energies >50 keV during the OSSE observation, and th

Xiao-Gang He

The decay modes $B$ to $ππ$, $ψK_S$, $K^- D$, $πK$ and $ηK$ are promising channels to study the unitarity triangle of the CP violating CKM matrix. In this paper I study the consequences of these measurements in the Weinberg model. I show that using the same set of measurements, the following different mechanisms for CP violation can be distinguished: 1) CP i

Christof Schmidhuber

Effective world-brane actions for solitons of ten-dimensional type IIA and IIB superstring theory are derived using the formulation of solitons as Dirichlet branes. The one-brane actions are used to recover predictions of SL(2,Z) strong-weak coupling duality. The two-brane action, which contains a hidden eleventh target space coordinate, is shown to be the e

Thang T. Q. Le

In [LMO] a 3-manifold invariant $Ω(M)$ is constructed using a modification of the Kontsevich integral and the Kirby calculus. The invariant $Ω$ takes values in a graded Hopf algebra of Feynman 3-valent graphs. Here we show that for homology 3-spheres the invariant $Ω$ is {\em universal} for all finite type invariants, i.e. $Ω_n$ is an invariant of order $3n$

A. Pich

These lectures provide an introductory overview of the dynamics of flavour-changing transitions. The main emphasis is put on present tests of the quark-mixing matrix structure and the phenomenological determination of its parameters. The interplay of strong interactions in weak decays and the important role of flavour symmetries for controlling the size of Q

B. Abdesselam, J. Beckers, A. Chakrabarti, N. Debergh

Nonlinear $sl(2)$ algebras subtending generalized angular momentum theories are studied in terms of undeformed generators and bases. We construct their unitary irreducible representations in such a general context. The linear $sl(2)$-case as well as its $q$-deformation are easily recovered as specific examples. Two other physically interesting applications c

C. R. Hagen

It has recently been suggested that an Aharonov-Bohm phase should be capable of detection using beams of neutral polarizable particles. A more careful analysis of the proposed experiment suffices to show, however, that it cannot be performed regardless of the strength of the external electric and magnetic fields.

W. Siegel

We introduce a random lattice corresponding to ordinary Feynman diagrams, with 1/p-squared propagators instead of the Gaussians used in the usual strings. The continuum limit defines a new type of string action with two worldsheet metrics, one Minkowskian and one Euclidean. The propagators correspond to curved lightlike paths with respect to the Minkowskian

G. von Gehlen

The McCoy-Roan integral representation for gaps of the integrable Z_n- symmetric Chiral Potts quantum chain is used to calculate the boundary of the incommensurable phase for various n. In the limit n -> \infty an analytic formula for this phase boundary is obtained. The McCoy-Roan formula gives the gaps in terms of a rapidity. For the lowest gap we conjectu

R. N. Mohapatra

A new supersymmetric grand unified model based on the gauge group $SU(5)\times SU(5)$ is discussed. The model has the feature that the conventional seesaw mechanism for neutrino masses is implemented using the $(15, 1)+(1,\bar{15)}$ representation. This multiplet may have a better chance of arising from level two compactification of superstring theories than

J. Bartels, J. R. Forshaw, H. Lotter, M. Wusthoff

The cross section for elastic vector meson production in photon-proton interactions at large $t$ is considered using the exact analytic solution of the BFKL equation in the azimuthally symmetric $n=0$ limit. We use a non-relativistic model for the vector meson production and find a small shrinkage in the $t$-distribution with increasing energy.

Efstratios Tsantilis, Roland A. Puntigam, Friedrich W. Hehl

Recently Pawłowski and Rcaczka proposed a unified model for the fundamental interactions which does not contain a physical Higgs field. The gravitational field equation of their model is rederived under heavy use of the computer algebra system Mathematica and its package MathTensor.

Michael P. Lamoureux

A set of meet-irreducible ideals is described for a class of maximal triangular almost finite algebras. This set forms a topological space under the hull-kernel closure, and there is a one-to-one correspondence between closed sets in this space and ideals in the AF algebra. Some connections with nest representations and nest-primitive ideals are also describ

Derek K. K. Lee, Don H. Kim, Patrick A. Lee

We study the effect of a strongly fluctuating gauge field on a degenerate Bose liquid, relevant to the charge degrees of freedom in doped Mott insulators. We find that the superfluidity is destroyed. The resulting metallic phase is studied using quantum Monte Carlo methods. Gauge fluctuations cause the boson world lines to retrace themselves. We examine how

Pablo Ordejon, Emilio Artacho, Jose M. Soler

We present a method to perform fully selfconsistent density-functional calculations, which scales linearly with the system size and which is well suited for very large systems. It uses strictly localized pseudoatomic orbitals as basis functions. The sparse Hamiltonian and overlap matrices are calculated with an $O(N)$ effort. The long range selfconsistent po

David Branch, Peter Nugent, Adam Fisher

Because Type Ia supernovae (SNe Ia) are not perfect standard candles, it is important to be able to use distance-independent observables (DIOs) to define subsets of SNe Ia that are ``nearly standard candles'' or to correct SN Ia absolute magnitudes to make them nearly homogeneous (``standardized candles''). This is not crucial for the measure

Roelof S. de Jong

The statistics of the fundamental bulge and disk parameters of galaxies and their relation to the Hubble sequence were investigated by an analysis of optical and near-infrared observations of 86 face-on spiral galaxies. The availability of near-infrared K-passband data made it possible for the first time to trace fundamental parameters related to the luminou

Andrei Linde

We discuss two important modifications of inflationary paradigm. Until very recently we believed that inflation automatically leads to flatness of the universe, Omega = 1. We also thought that post-inflationary phase transitions in GUTs may occur only after thermalization, which made it very difficult to have baryogenesis in GUTs and to obtain superheavy top

Fernando Cukierman

Let $X \subset \Bbb P^r$ be a smooth algebraic curve in projective space, over an algebraically closed field of characteristic zero. For each $m \in \Bbb N$, the $m$-flexes of $X$ are defined as the points where the osculating hypersurface of degree $m$ has higher contact than expected, and a hypersurface $H \subset \Bbb P^r$ is called a $m$-Hessian if it cu

S. Chaudhuri, D. A. Lowe

We analyze the general class of supersymmetry preserving orbifolds of strong/weak Type IIA/heterotic dual pairs in six dimensions and below. A unified treatment is given by considering compactification to two spacetime dimensions and constructing orbifolds by subgroups of the Fischer-Greiss monster, utilizing the moonshine results of Conway and Norton. Duali

Andreas Seeger, Stephen Wainger, James Wright

Let $A_tf(x)=\int f(x+ty)dσ(y)$ denote the spherical means in $\Bbb R^d$ ($dσ$ is surface measure on $S^{d-1}$, normalized to $1$). We prove sharp estimates for the maximal function $M_E f(x)=\sup_{t\in E}|A_tf(x)|$ where $E$ is a fixed set in $\Bbb R^+$ and $f$ is a {\it radial} function $\in L^p(\Bbb R^d)$. Let $p_d=d/(d-1)$ (the critical exponent of Stein

M. Carena, H. E. Haber, C. E. M. Wagner

A supersymmetric model with four generations is proposed, in which the top quark is approximately degenerate in mass with the $W^{\pm}$ gauge boson, $m_t\simeq m_W$, leading to values of $R_b$ in better agreement with the present experimental data than in the Standard Model. The model shares many of the good features of the minimal supersymmetric extension o

Masaru Siino

Quantum fields are investigated in the (2+1)-open-universes with non-trivial topologies by the method of images. The universes are locally de Sitter spacetime and anti-de Sitter spacetime. In the present article we study spacetimes whose spatial topologies are a torus with a cusp and a sphere with three cusps as a step toward the more general case. A quantum

P. vanBeek, D. W. Manchak

Many applications -- from planning and scheduling to problems in molecular biology -- rely heavily on a temporal reasoning component. In this paper, we discuss the design and empirical analysis of algorithms for a temporal reasoning system based on Allen's influential interval-based framework for representing temporal information. At the core of the syst

A. V. Andreev, O. Agam, B. D. Simons, B. L. Altshuler

The Bohigas--Giannoni--Schmit conjecture stating that the statistical spectral properties of systems which are chaotic in their classical limit coincide with random matrix theory is proved. For this purpose a new semiclassical field theory for individual chaotic systems is constructed in the framework of the non--linear $σ$-model. The low lying modes are sho

J. Craig Wheeler, S. -W. Kim, M. D. Moscoso, M. Kusunose

The most plausible mechanism for triggering the outburst of black hole candidate X-ray transients is the ionization thermal instability. The disk instability models can give the observed mass flow in quiescence, but not the X-ray spectrum. Self-irradiation of the disk in outburst may not lead to X-ray reprocessing as the dominant source of optical light, but

Roelof S. de Jong

In this paper I present a new two-dimensional decomposition technique, which models the surface photometry of a galaxy with an exponential light profile for both bulge and disk and, when necessary, with a Freeman bar. The new technique was tested for systematic errors on both artificial and real data and compared with widely used one-dimensional decompositio

Y. D. Mayya, T. P. Prabhu

A study of star formation is carried out on 35 giant extragalactic HII regions (GEHRs) in seven galaxies using optical photometric data in BVR broad bands and in the emission line of H alpha. Interstellar extinction, metallicity and nebular contributions to the broad bands are estimated using spectroscopic data on these objects. Dimensionless diagrams involv