January 1997 arXiv papers — page 2

Emanuele Manfredini

In this work I present a numerical study of the Finite Size Scaling (FSS) of a correlation length in the framework of the $CP ^{N-1}$ model by means of the 1/N expansion. This study has been thought as propedeutical to the application of FSS to the measure on the lattice of a new coupling constant $f_{x}(1/R)$, defined in terms or rectangular Wilson Loops. I

Takashi Dateki

We study the critical behavior of the D (2<D<4) dimensional Gross-Neveu model with a Thirring interaction, where a vector-vector type four-fermi interaction is on equal terms with a scalar-scalar type one. By using inversion method up to the next-to-leading order of 1/N expansion, we construct a gauge invariant effective potential. We show the existence of t

Frank Antonsen

A new non-perturbative approach to quantum theory in curved spacetime and to quantum gravity, based on a generalisation of the Wigner equation, is proposed. Our definition for a Wigner equation differs from what have otherwise been proposed, and does not imply any approximations. It is a completely exact equation, fully equivalent to the Heisenberg equations

Frank Antonsen, Karsten Bormann

We extend recent work by Elizalde et al. to incorporate curvatures which are not small and backgrounds which are not just $S^2\times R^2, S^1\times S^1 \times R^2$. Some possible problems in their paper is also pointed out.

H. Figueroa, J. M. Gracia-Bondia, F. Lizzi, J. C. Varilly

Using the formalism of superconnections, we show the existence of a bosonic action functional for the standard K-cycle in noncommutative geometry, giving rise, through the spectral action principle, only to the Einstein gravity and Standard Model Yang-Mills-Higgs terms. It provides an effective nonminimal coupling in the bosonic sector of the Lagrangian.

S. Yu. Khlebnikov, I. I. Tkachev

We show that gravitational radiation is produced quite efficiently in interactions of classical waves created by resonant decay of a coherently oscillating field. For simple models of chaotic inflation in which the inflaton interacts with another scalar field, we find that today&#39;s ratio of energy density in gravitational waves per octave to the critical

P. Post, K. Schilcher

We present the results of the first two-loop calculation of a form factor in full $SU(3) \times SU(3)$ Chiral Perturbation Theory. We choose a specific linear combination of $π^+, K^+, K^0$ and $Kπ$ form factors (the one appearing in Sirlin&#39;s theorem) which does not get contributions from order $p^6$ operators with unknown constants. For the charge radii

V. A. Khoze, W. Ochs

In this review we discuss the analytical perturbative approach, based on perturbative QCD and Local Parton Hadron Duality (LPHD), and its application to multiparticle production in jets in the semisoft region. Analytical formulae are presented for various observables within the accuracy of the Modified Leading Logarithmic Approximation (MLLA), i.e. with term

H. Nunokawa, V. B. Semikoz, A. Yu. Smirnov, J. W. F. Valle

Electron polarization induced by magnetic fields can modify the potentials relevant for describing neutrino conversions in media with magnetic fields. The magnitudes of polarization potentials are determined for different conditions. We show that variations of the electron polarization along the neutrino trajectory can induce resonant conversions in the acti

S. Peris, E. de Rafael

We discuss the contribution of ultraviolet (UV) renormalons in QCD to two-point functions of quark current operators. This explicitly includes effects due to the exchange of one renormalon chain as well as two chains. It is shown that, when the external euclidean momentum of the two-point functions becomes smaller than the scale $Λ_L$ associated with the Lan

Stefano Borgani, Antonio Masiero

We review the prospects for dark matter (DM) in two classes of supersymmetric (SUSY) models which are characterized by the different mechanism of SUSY breaking, namely the more common supergravity models with very large scale of SUSY breaking and the recent schemes where SUSY is broken at a relatively low scale and gravitinos are likely to be the lightest SU

Robert J. Scherrer, Alexander Vilenkin

We simulate the formation of cosmic strings at the zeros of a complex Gaussian field with a power spectrum $P(k) \propto k^n$, specifically addressing the issue of the fraction of length in infinite strings. We make two improvements over previous simulations: we include a non-zero random background field in our box to simulate the effect of long-wavelength m

K. Williams

A straightforward calculation reveals the essentially nonlocal character of the leading heavy $Q\bar{Q}$ interaction arising from nonperturbative gluon field correlations in the model of a fluctuating QCD vacuum. In light of this quarkonium spin splitting ratio predictions which have supported the scalar confinement ansatz are reconsidered as a specific exam

Burcu Ortakaya, Yiğit Gündüç, Meral Aydın, Tarık Çelik

The scaling behavior of fluctuations in cluster size is studied in q=5 and 7 state Potts models. This quantity exhibits scaling behavior on small lattices where the scaling of local operators like energy fluctuations and Binder cumulant can not be expected.

L. Del Debbio, S. J. Hands, J. C. Mehegan

We formulate the three dimensional Thirring model on a spacetime lattice and study it for various even numbers of fermion flavors N_f by Monte Carlo simulation. We find clear evidence for spontaneous chiral symmetry breaking at strong coupling, contradicting the predictions of the 1/N_f expansion. The critical point appears to correspond to an ultra-violet f

M. Paulini

We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and DO. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent BB= mixing results. An outlook of perspectives for top and B phys

Donald Marolf, José Mourão, Thomas Thiemann

This work addresses a specific technical question of relevance to canonical quantization of gravity using the so-called new variables and loop-based techniques of Ashtekar, Rovelli, and Smolin. In particular, certain `superselection laws&#39; that arise in current applications of these techniques to solving the diffeomorphism constraint are considered. Their

H. F. Goenner, G. Yu. Bogoslovsky

A particular Finsler-metric proposed in [1,2] and describing a geometry with a preferred null direction is characterized here as belonging to a subclass contained in a larger class of Finsler-metrics with one or more preferred directions (null, space- or timelike). The metrics are classified according to their group of isometries. These turn out to be isomor

David Hochberg, Arkadiy Popov, Sergey V. Sushkov

We present the first results of a self-consistent solution of the semiclassical Einstein field equations corresponding to a Lorentzian wormhole coupled to a quantum scalar field. The specific solution presented here represents a wormhole connecting two asymptotically spatially flat regions. In general, the diameter of the wormhole throat, in units of the Pla

Fabio Bagarello

We discuss the possibility of introducing a multi-resolution in a Hilbert space which is not necessarily a space of functions. We investigate which of the classical properties can be translated to this more general framework and the way in which this can be done. We comment on the procedure proposed by means of many examples.

Fabio Bagarello

In this paper we discuss some topics related to the general theory of frames. In particular we focus our attention to the existence of different &#39;reconstruction formulas&#39; for a given vector of a certain Hilbert space and to some refinement of the perturbative approach for the computation of the dual frame.

F. Simmel, T. Heinzel, D. A. Wharam

The fluctuations and the distribution of the conductance peak spacings of a quantum dot in the Coulomb-blockade regime are studied and compared with the predictions of random matrix theory (RMT). The experimental data were obtained in transport measurements performed on a semiconductor quantum dot fabricated in a GaAs-AlGaAs heterostructure. It is found that

S. Picozzi, A. Continenza, A. J. Freeman

The structural and electronic properties in common anion (GaSb)_1/(InSb)_1 and common cation (InAs)_1/(InSb)_1 [111] ordered superlattices have been determined using the local density total energy full potential linearized augmented plane wave method. The influence of the ordering direction, strain conditions and atomic substitution on the electronic propert

Kyungsun Moon, Kieran Mullen

Double-layer quantum Hall systems at total filling factor $ν_T=1$ can exhibit a commensurate-incommensurate phase transition driven by a magnetic field $B_{\parallel}$ oriented parallel to the layers. Within the commensurate phase, the lowest charge excitations are believed to be linearly-confined Meron pairs, which are energetically favored to align with $B

Ya. M. Blanter, Rosario Fazio, Gerd Schoen

Various properties of mesoscopic two-dimensional Josephson junction arrays are reviewed. Particular attention is paid to structure of the topological excitations, charges and vortices, which are shown to be dual to each other. This duality persists in the presence of external magnetic fields and offset charges, which influence vortices and charges in an equi

Henk van Beijeren, Enrico Carlon

Networks of steps, seen in STM observations of vicinal surfaces on Au and Pt (110), are analyzed. A simple model is introduced for the calculation of the free energy of the networks as function of the slope parameters, valid at low step densities. It predicts that the networks are unstable, or at least metastable, against faceting and gives an equilibrium cr

A. M. M. Pruisken, K. Schoutens

We address two fundamental issues in the physics of the quantum Hall effect: a unified description of scaling behavior of conductances in the integral and fractional regimes, and a quasi-particle formulation of the chiral Luttinger Liquids that describe the dynamics of edge excitations in the fractional regime.

Evgueni Kochetov, Vladimir Yarunin

We show that the t-J Hamiltonian is not in general reduced to H(S,f), where S and f stand for independent ([S,f]=0) SU(2) (spin) generators and spinless fermionic (hole) field, respectively. The proof is based upon an identification of the Hubbard operators with the generators of the su(2|1) superalgebra in the degenerate fundamental representation and ensui

Yvon Georgelin, Thierry Masson, Jean-Christophe Wallet

We consider the action of the modular group $Γ(2)$ on the set of positive rational fractions. From this, we derive a model for a classification of fractional (as well as integer) Hall states which can be visualized on two ``visibility&#34; diagrams, the first one being associated with even denominator fractions whereas the second one is linked to odd denomin

T. J. Hagenaars, E. H. Brandt, R. E. Hetzel, W. Hanke

We study the vortex-line lattice and liquid phases of a clean type-II superconductor by means of Monte Carlo simulations of the lattice London model. Motivated by a recent controversy regarding the presence, within this model, of a vortex-liquid regime with longitudinal superconducting coherence over long length scales, we directly compare two different ways

Stefan Meixner, Werner Hanke, Eugene Demler, Shou-Cheng Zhang

We present numerical evidence for the approximate SO(5) symmetry of the Hubbard model on a 10 site cluster. Various dynamic correlation functions involving the $π$ operators, the generators of the SO(5) algebra, are studied using exact diagonalisation, and are found to possess sharp collective peaks. Our numerical results also lend support on the interpretat

D. N. Aristov, D. R. Grempel

We study the spin fluctuation of the oxygen deficient planes of YBa(2)Cu(3)O(6+x). The Cu-O chains that constitute these planes are described by a model that includes antiferromagnetic interactions between spins and Kondo-like scattering of oxygen holes. The spectrum of magnetic excitations shows the presence of incommensurate dynamic fluctuations along the

Zheng Weihong

Various series expansions have been developed for the two-layer, S=1/2, square lattice Heisenberg antiferromagnet. High temperature expansions are used to calculate the temperature dependence of the susceptibility and specific heat. At T=0, Ising expansions are used to study the properties of the Néel-ordered phase, while dimer expansions are used to calcula

D. V. Averin, A. N. Korotkov, A. J. Manninen, J. P. Pekola

We predict theoretically and observe in experiment that the differential conductance of a superconducting SET transistor exhibits a peak which is a complete analogue in a macroscopic system of a standard resonant tunneling peak associated with tunneling through a single quantum state. In particular, in a symmetric transistor, the peak height is universal and

Yoshiki Kuramoto, Hiroya Nakao

Large assemblies of nonlinear dynamical units driven by a long-wave fluctuating external field are found to generate strong turbulence with scaling properties. This type of turbulence is so robust that it persists over a finite parameter range with parameter-dependent exponents of singularity, and is insensitive to the specific nature of the dynamical units

Hans Henrik Rugh

We present a new dynamical approach for measuring the temperature of a Hamiltonian dynamical system in the micro canonical ensemble of thermodynamics. We show that under the hypothesis of ergodicity the temperature can be computed as a time-average of the functional, div(grad H/|grad H|^2), on the energy-surface. Our method not only yields an efficient compu

G. Zoeller, R. Engbert, S. Hainzl, J. Kurths

We present a new technique in order to quantify the dynamics of spatially extended systems. Using a test on the existence of unstable periodic orbits, we identify intermediate spatial scales, wherein the dynamics is characterized by maximum nontrivial determinism. This method is applied to earthquake catalogues containing time, coordinates and magnitude. As

C. D. Wilson, C. E. Walker, M. D. Thornley

We have observed the $^{12}$CO J=2-1, J=3-2, and $^{13}$CO J=2-1 lines in a sample of seven giant molecular clouds in the Local Group spiral galaxy M33. The $^{12}$CO/$^{13}$CO J=2-1 line ratio is constant across the entire sample, while the observed $^{12}$CO J=3-2/J=2-1 line ratio has a weak dependence on the star formation environment of the cloud, with l

F. X. Timmes, J. W. Truran, J. T. Lauroesch, D. G. York

Plausible ratios of deuterium to hydrogen D/H as a function of metallicity, time, and redshift are investigated. Guided by the heavy element abundance patterns observed locally in Galactic dwarf stars and at large redshift in quasi-stellar object absorption line systems, empirical evolution of the relative abundance ratios Li/D, B/D, N/D, O/D, and F/D for QS

F. X. Timmes, R. Diehl, D. H. Hartmann

Gamma-rays from the decay of $^{26}$Al offer a stringent constraint on the Galaxy&#39;s global star formation rate over the past million years, supplementing other methods for quantifying the recent Galactic star formation rate, such as equivalent widths of H$α$ emission. Advantages and disadvantages of using $^{26}$Al gamma-ray measurements as a tracer of t

Limin Lu, Wallace L. W. Sargent, Thomas A. Barlow

We present evidence that damped Lyman-alpha galaxies detected in spectra of quasars may not have started forming stars until the redshift z~3. If damped Lyman-alpha absorbers are the progenitors of disk galaxies, then the above result may indicate that star formation in galactic disks first began at z~3.

F. X. Timmes, D. D. Clayton

We examine the consequences and implications of the possibility that the best-fit $m$=4/3 line of the silicon isotopic ratios measured in mainstream SiC grains is identical or parallel to to the mean ISM evolution line of the silicon isotopes. Even though the mean ISM evolution proceeds along a line of unity slope when deviations are expressed in terms of th

Zoltan Haiman, Abraham Loeb

We use a spherical hydrodynamics code to show that in cold dark matter cosmologies, the first stars form at z=50 through the direct collapse of gas in low-mass systems (approx 10^4 solar masses). Photons from the first stars easily photodissociate the molecular hydrogen throughout the universe and so molecular cooling does not affect the subsequent fragmenta

Sujan Sengupta

The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating the effect of space-time curvature produced by the intense gravitational field of the star. It is shown that general relativistic effect reduces the magnetic field decay rate substaintially and specially at the late time of the evolution the decay rat

Rene A. Ong, the STACEE Collaboration

STACEE is a proposed atmospheric Cherenkov telescope for ground-based gamma-ray astrophysics between 25 and 500 GeV. The telescope will make use of the large solar mirrors (heliostats) available at a solar research facility to achieve an energy threshold lower than any existing ground-based instrument. This paper describes the development of STACEE, includin

T. M. Brown, H. C. Ferguson, A. F. Davidsen, B. Dorman

We have analyzed the far-ultraviolet (FUV) spectra of six elliptical and S0 galaxies in order to characterize their hot stellar populations. The spectra were obtained using the Hopkins Ultraviolet Telescope (HUT) in March 1995. These data, together with the spectra of two galaxies observed with HUT in 1990, represent the only FUV spectra of early type galaxi

S. Campana, S. Mereghetti, L. Stella, M. Colpi

We report on a ROSAT-HRI observation of the soft X-ray transient Cen X-4 during quiescence. We discover a variation in the flux by a factor of 3 in less than four days. This relatively fast variation, the first observed from a quiescent soft X-ray transient, rules out some of the emission mechanisms that have been proposed for the quiescent flux. Accretion e

A. K. Romer, R. C. Nichol, C. A. Collins, D. J. Burke

In contrast to claims of strong negative evolution by other groups, we find no evidence for evolution of the X-ray cluster luminosity function out to z=0.7

Gianni Fiorentini, Camillo Acerbi

We perform an extensive investigation of the sensitivity to non-vanishing tau-neutrino mass in a large water Cherenkov detector, developing an analysis method for neutrino events originated by a supernova explosion. This approach, based on directional considerations, provides informations almost undepending on the supernova model. We analyze several theoreti

Eli Waxman, John Bahcall

Observations suggest that $γ$-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. We show that a large fraction, $\ge 10%$, of the fireball energy is expected to be converted by photo-meson production to a burst of $\sim10^{14} eV$ neutrinos. A km^2 neutrino detector would observe at least several tens of event

Arnaud Beauville

The aim of these notes is to explain the remarkable formula found by Yau and Zaslow to express the number of rational curves on a K3 surface. Projective K3 surfaces fall into countably many families F(g) (g>0); a surface in F(g) admits a g-dimensional linear system of curves of genus g. Such a system contains a positive number, say n(g), of rational (highly

N. Redington

It is argued that the fifth coordinate should correspond to an intensive parameter rather than to rest-mass as originally proposed by Wesson.

Pavel Etingof, David Kazhdan

This paper is a continuation of &#34;Quantization of Lie bialgebras, I&#34; (q-alg/9606005). We show that the quantization procedure defined in &#34;Quantization of Lie bialgebras, I&#34; is given by universal acyclic formulas and defines a functor from the category of Lie bialgebras to the category of quantized universal enveloping algebras. We also show th

Sayan Kar, Swapna Mahapatra

A novel ansatz for solving the string equations of motion and constraints in generic curved backgrounds, namely the planetoid ansatz, was proposed recently by some authors. We construct several specific examples of planetoid strings in curved backgrounds which include Lorentzian wormholes, spherical Rindler spacetime and the 2+1 dimensional black hole. A sem

D. Müller, O. V. Teryaev

The generalization of the axial anomaly is considered. It is shown that bilocal axial quark operators on the light cone possess, beside the point-like anomaly, also a light-like anomaly. The consequences for the definition of anomaly-free quark distribution functions and the effect of both gluon coefficient function and splitting kernels in polarized deep in

Marco Ameduri, Costas J. Efthimiou

In this work we apply the Weiss, Tabor and Carnevale integrability criterion (Painlevé analysis) to the classical version of the two dimensional Bukhvostov-Lipatov model. We are led to the conclusion that the model is not integrable classically, except at a trivial point where the theory can be described in terms of two uncoupled sine-Gordon models.

Matthew J. Slater

We use the microscopic instanton calculus to determine the one-instanton contribution to the quantum modulus u_3=<Tr(ϕ^3)> in N=2 SU(N_c) supersymmetric QCD with N_f<2N_c fundamental flavors. This is compared with the corresponding prediction of the hyperelliptic curves which are expected to give exact solutions in this theory. The results agree up to certai

Rosalba Perna, Abraham Loeb

The damped Lyman alpha absorbers (DLAs) in quasar spectra are believed to be the progenitors of present-day disk galaxies. We examine the probability for microlensing of background quasars by stars in their DLAs. Microlensing by an individual star should magnify the continuum but not the broad emission lines of the quasars. Consequently, the equivalent width

P. A. Baikov, E. E. Boos, M. N. Dubinin, V. F. Edneral

The CompHEP package was developed for calculations of decay and high energy collision processes with, correspondingly, up to 5 and 4 final particles in the lowest order (tree) approximation. The main idea put into CompHEP was to make available passing from the Lagrangian to final distributions efficiently with high level automation what is extremely needed i

L. Sehn, C. Fuchs, Amand Faessler

The formalism of the relativistic (or Dirac-) Brueckner approach in infinite nuclear matter is described. As nucleon-nucleon interaction the one-boson exchange potentials Bonn A,B,C and for comparison the Walecka model are used. The T-matrix is determined from the Thompson equation and is projected onto five covariant amplitudes. By the restriction to positi

M. Gambera, A. Pagliaro, V. Antonuccio-Delogu, U. Becciani

Evidence for clustering within the Coma cluster is found by means of a multiscale analysis of the combined angular-redshift distribution. We have compiled a catalogue of 798 galaxy redshifts from published surveys from the region of the Coma cluster. We examine the presence of substructure and of voids at different scales ranging from $\sim 1 to \sim 16 h^{-

P. N. Pandita

We consider the neutralino mass matrix in a supersymmetric theory based on SU(2) $\times$ U(1) gauge group with arbitrary number of singlet, doublet and triplet Higgs superfields. We derive an upper bound on the mass of the lightest neutralino, and a lower bound on the mass of the heaviest neutralino, in such a theory. Assuming grand unification of the gauge

A. Sorin

The discrete symmetry transformations of the N=2 supersymmetric (n,m)-GNLS hierarchy are constructed. Their bosonic limit is analyzed and new discrete symmetries of the modified GNLS hierarchy are derived. The explicit relations connecting the integrable hierarchy, produced by the junction of the Lax operators for the N=2 supersymmetric a=4 KdV and (n-1,m)-G

Mina Aganagic, Jaemo Park, Costin Popescu, John H. Schwarz

This paper presents a 6d world-volume action that describes the dynamics of the M theory five-brane in a flat 11d space-time background. The world-volume action has global 11d super-Poincare invariance, as well as 6d general coordinate invariance and kappa symmetry, which are realized as local symmetries. The paper mostly considers a formulation in which gen

Michael Bershadsky, Andrey Johansen, Tony Pantev, Vladimir Sadov

Branches of moduli space of F-theory in four dimensions are investigated. The transition between two branches is described as a 3-brane-instanton transition on a 7-brane. A dual heterotic picture of the transition is presented and the F-theory - heterotic theory map is given. The F-theory data - complex structure of the Calabi-Yau fourfold and the instanton

Ira Z. Rothstein, M. B. Wise

The Operator Product Expansion, in conjunction with the power counting of non-relativistic field theory, is used to examine the end-point region of the radiative decay of heavy quark bound states with $^3S_1$ quantum numbers, $Q\bar{Q}\rightarrow γ+X$. We identify an infinite class of operators that determine the shape of the photonic end-point spectrum. The

Girish S. Setlur

An attempt is made to generalise the ideas introduced by Haldane and others regarding Bosonizing the Fermi surface. The present attempt involves introduction of Bose fields that correspond to displacements of the Fermi sea rather than just the Fermi surface. This enables the study of short wavelength fluctuations of the Fermi surface and hence the dispersion

A. N. Leznov, A. Sorin

The integrability of the recently introduced N=2 supersymmetric f-Toda chain, under appropriate boundary conditions, is proven. The recurrent formulae for its general solutions are derived. As an example, the solution for the simplest case of boundary conditions is presented in explicit form.

A. S. Holevo

A survey of the probabilistic approaches to quantum dynamical semigroups with unbounded generators is given. An emphasis is made upon recent advances in the structural theory of covariant Markovian master equations. The relations with the classical Levy-Khinchin formula are elucidated. As an example, a complete characterizations of the Galilean covariant irr

S. Goedecker, O. V. Ivanov

The Coulomb problem for continuous charge distributions is a central problem in physics. Powerful methods, that scale linearly with system size and that allow us to use different resolutions in different regions of space are therefore highly desirable. Using wavelet based Multi Resolution Analysis we derive for the first time a method which has these propert

Augusto Gonzalez

The existence of radial solutions of a nonlinear Dirichlet problem in a ball is translated to the language of Mechanics, i.e. to requirements on the time of motion of a particle in an external potential and under the action of a viscosity force. This approach reproduces existing theorems and, in principle, provides a method for the analysis of the general ca

A. G. Khachatryan

One dimensional nonlinear plasma wake-fields excited by a single bunch and by series of bunches are considered. Essential differences are brought to light between negatively charged bunch case and positively one. The bunches with nonuniform distributions of density are investigated. The obtained results show dependence of excited potential electric fields on

S. S. Avancini, J. R. Marinelli, D. P. Menezes, M. M. Watanabe de Moraes

The quon algebra, which interpolates between the Bose and Fermi algebras and depends on a free paramenter $q$, is used to generate a deformed Dyson boson expansion of the quadrupole operator. Then we obtain a quadrupole-quadrupole hamiltonian, for a single j-shell, in terms of this deformed bosonic operator. The hamiltonian is diagonalized and its eigenvalue

Y. Dewulf, D. Van Neck, L. Van Daele, M. Waroquier

Long-range correlations, which are partially responsible for the observed fragmentation and depletion of low-lying single-particle strength, are studied in the Green&#39;s function formalism. The self-energy is expanded up to second order in the residual interaction. We compare two methods of implementing self-consistency in the solution of the Dyson equatio

Yong-Wan Kim, Mu-In Park, Young-Jai Park, Sean J. Yoon

The BRST quantization of the Abelian Proca model is performed using the Batalin-Fradkin-Tyutin and the Batalin-Fradkin-Vilkovisky formalism. First, the BFT Hamiltonian method is applied in order to systematically convert a second class constraint system of the model into an effectively first class one by introducing new fields. In finding the involutive Hami

Giampiero Esposito, Giuseppe Pollifrone

A gauge-averaging functional of the axial type is studied for simple supergravity at one loop about flat Euclidean four-space bounded by a three-sphere, or two concentric three-spheres. This is a generalization of recent work on the axial gauge in quantum supergravity on manifolds with boundary. Ghost modes obey nonlocal boundary conditions of the spectral t

M. Kreuzer, H. Skarke

We present a general scheme for identifying fibrations in the framework of toric geometry and provide a large list of weights for Calabi--Yau 4-folds. We find 914,164 weights with degree $d\le150$ whose maximal Newton polyhedra are reflexive and 525,572 weights with degree $d\le4000$ that give rise to weighted projective spaces such that the polynomial defin

Andrei Mikhailov

We discuss the algebraic structure of the spin chains related to high energy scattering in QCD. We study the sl(2) Yangian symmetry and possible generalizations to nonzero spin and anisotropy parameter.

D. -S. Lee, C. N. Leung, Y. J. Ng

Using the nonperturbative Schwinger-Dyson equation, we show that chiral symmetry is dynamically broken in QED at weak couplings when an external magnetic field is present, and that chiral symmetry is restored at temperatures above $T_c \simeq απ^2/\sqrt{2 π|eH|}$, where $α$ is the fine structure constant and $H$ is the magnetic field strength.

K. Bardakci, L. M. Bernardo

We propose a new approach for deriving the string field equations from a general sigma model on the world sheet. This approach leads to an equation which combines some of the attractive features of both the renormalization group method and the covariant beta function treatment of the massless excitations. It has the advantage of being covariant under a very

Bernard de Wit

We review models of supersymmetric quantum mechanics that are important in the description of supermembranes and of Dirichlet particles, which play a role in the context of M-theory.

Ansar Fayyazuddin, Douglas J. Smith

We find p-brane solutions to the recently proposed IKKT IIB matrix theory for all odd p. We also propose central charges for the p-branes.

A. V. Shurgaia

Euclidean field theory on 4-dimensional sphere is suggested for the study of high energy multiparticle production. The singular classical field configurations are found in scalar and SU(2)-gauge theories and the cross section of 2->n processes is calculated. It is shown,that the cross section has a maximum at the energy compared to the sphaleron mass.

Francois Gelis

In this paper, we review the set of rules specific to the calculation of the imaginary part of a Green&#39;s function at finite temperature in the real-time formalisms. Emphasis is put on the clarification of a recent controversy concerning these rules in the &#34;1/2&#34; formalism, more precisely on the issue related to the interpretation of these rules in

F. Boudjema

It is argued that the next linear colliders can serve as W factories that may be exploited for precision tests on the properties of the massive gauge bosons. The connection between the probing of the symmetry breaking sector and precise measurement of the self-couplings of the weak vector bosons is stressed. The discussion relies much on the impact of the pr

Michael C. Birse, Thomas D. Cohen, Judith A. McGovern

Group-theoretic arguments are used to determine the dependence of two-point correlators of quark bilinears on the current quark masses. The leading difference between $π$ and $δ$ correlators is found to be of order $m_s$ times a U(1)$_{\scriptscriptstyle A}$-violating correlator. These general arguments are consistent with Schaefer&#39;s observation that if

M. G. Ryskin, Yu. M. Shabelski

The background due to the direct diffractive dissociation of the photon into the $π^+π^-$-pair to the &#34;elastic&#34; diffractive $ρ^0$-meson production in electron-proton collisions is calculated. The amplitude for the background process $γp \to π^+ π^- p$ is proportional to the $π$-meson - proton cross section. Therefore, describing the HERA data, we can

Gongru Lu, Yigang Cao, Jinshu Huang, Junde Zhang

We calculate one-loop corrections to the single-top-quark production via $q\overline{q}&#39; \to t\overline b$ at the Fermilab Tevatron from the Pseudo-Goldstone bosons ( PGBs ) in the framework of one generation technicolor model. The maximum correction to the total cross section for the single-top-quark production is found to reach -2.4% relative to the tr

Gaitri Saini, Satish D. Joglekar

We consider the nonlocal version of the Weinberg Salam model (following Kleppe et al.) with a finite parameter $Λ$ signifying a fundamental length scale.We calculate the extra contributions to the anomalous magnetic moment of the muon coming from the nonlocal structure in this model.We find that the nonlocal contribution can be comparable to weak contributio

M. Rogalla, Th. Eich, N. Evans, R. Geppert

To investigate the trapping and detrapping in SI-GaAs particle detectors we analyzed the signals caused by 5.48 MeV alpha particles with a charge sensitive preamplifier. From the bias and temperature dependence of these signals we determine the activation energies of two electron traps. Additional simulation and measurements of the lifetime as a function of

N. Redington

The metric perturbation tensor corresponding to a transverse oscillation of spacetime is composed of products of cosines. When averaged over many wavelengths, such a metric may look either Minkowskian or Euclidean at large scales, depending on the amplitude and wavelength of the oscillation.

Marc A. Rieffel

The purpose of this note is to show that the construction of the C*-algebra for the space-time uncertainty relations which was introduced by Doplicher, Fredenhagen and Roberts fits comfortably into the strict deformation quantization construction introduced earlier by the author.

Angela Foerster

An integrable version of the supersymmetric t-J model which is quantum group invariant as well as periodic is introduced and analysed in detail. The model is solved through the algebraic nested Bethe ansatz method.

Carlos J. Camacho

In a recent Letter, Gutin, Abkevich, and Shakhnovich (GAS) reported on a series of dynamical Monte Carlo simulations on lattice models of proteins. Based on these highly simplified models, they found that four different potential energies lead to four different folding time scales tau_f, where tau_f scales with chain length as N^lambda (see, also, Refs. [2-4

Mikko Karttunen, Nikolas Provatas, Tapio Ala-Nissila, Martin Grant

We study the nucleation and growth of flame fronts in slow combustion. This is modeled by a set of reaction-diffusion equations for the temperature field, coupled to a background of reactants and augmented by a term describing random temperature fluctuations for ignition. We establish connections between this model and the classical theories of nucleation an

J. Röhler, P. W. Loeffen, S. Müllender, K. Conder

We have measured the extended x-ray absorption-fine-structure (EXAFS) at the Y-K edge of YBa_2Cu_3O_x for x=6.801, 6.947, 6.968, 6.984 at T=20-300 K. Across the underdoped-overdoped transition the Y-Cu2 pairs exhibit harmonic vibrations which freeze out in the superconducting phase, whereas the Y-O2,3 pairs exhibit strong anharmonicities with a singularity a

Ruihong Yue, Tetsuo Deguchi

We found the eigenvalues of the transfer matrix for the 2-D inhomogeneous statistical model with twisted boundary condition by using the analytic Bethe Ansatz method. In the uniform case, the derived hamiltonian generalizes the 1-D Hubbard model with the twisted boundary. We also give the energy spectra for the derived hamiltonian.

Richard Barvainis

The study of molecular gas in quasar host galaxies addresses a number of interesting questions pertaining to the hosts&#39; ISM, to unified schemes relating quasars and IR galaxies, and to the processes fueling nuclear activity. In this contribution I review observations of molecular gas in quasar hosts from z=0.06 to z=4.7. The Cloverleaf quasar at z=2.5 is

Li-Zhi Fang, Jesus Pando

We present a detailed review of large-scale structure (LSS) study using the discrete wavelet transform (DWT). After describing how one constructs a wavelet decomposition we show how this bases can be used as a complete statistical discription of LSS. Among the topics studied are the the DWT estimation of the probability distribution function; the reconstruct

A. Naim

The problem of automated separation of stars and galaxies on photographic plates is revisited with two goals in mind : First, to separate galaxies from everything else (as opposed to most previous work, in which galaxies were lumped together with all other non-stellar images). And second, to search optically for galaxies at low Galactic latitudes (an area th