arXiv papers from June 1998

Donald Marolf

We show that the 1+1 dimensional reduction (i.e., the radial plane) of the Kruskal black hole can be embedded in 2+1 Minkowski spacetime and discuss how features of this spacetime can be seen from the embedding diagram. The purpose of this work is educational: The associated embedding diagrams may be useful for explaining aspects of black holes to students w

Rosa C. Orellana

We compute the weights, i.e. the values at the minimal idempotents, for the Markov trace on the Hecke algebra of type $B$ and type $D$. In order to prove the weight formula, we define representations of the Hecke algebra of type $B$ onto a reduced Hecke algebre of type $A$. To compute the weights for type $D$ we use the inclusion of the Hecke algebra of type

John R. Hiller, Stanley J. Brodsky

We study the physical electron in quantum electrodynamics expanded on the light-cone Fock space in order to address two problems: (1) the physics of the electron's anomalous magnetic moment $a_e$ in nonperturbative QED, and (2) the practical problems of ultraviolet regularization and renormalization in truncated nonperturbative light-cone Hamiltonian theory.

E. M. Henley

SU(3), baryon octets and a meson cloud model are compared for the flavor asymmetry of sea quarks in the $\Sigma^+$, as an example. Large differences are found, especially between SU(3) and the meson cloud model. We suggest Drell-Yan measurements of $\Sigma^{+}-p$ and $\Sigma^{+}- d$ to test the prediction of various models. We use the meson cloud model to pr

L. Vasiliu-Doloc, J. W. Lynn, A. H. Moudden, A. M. de Leon-Guevara

Neutron scattering has been used to study the structure and spin dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$. The magnetic structure of this system is ferromagnetic below T_C = 235 K. We see anomalies in the Bragg peak intensities and new superlattice peaks consistent with the onset of a spin-canted phase below T_{CA} = 205 K, which appears to be associated wi

V. Dmitrasinovic, T. Sato

We show the necessity of two-nucleon axial currents and associated pion emission/ absorption operators for the partial conservation of the axial current (PCAC) nuclear matrix elements with arbitrary nuclear dynamics described by a nonrelativistic Schroedinger equation. As examples we construct such nonrelativistic axial two-body currents in the linear- and h

Anthony J. Baltz, Alfred Scharff Goldhaber, Maurice Goldhaber

If, as suggested by the SuperKamiokande results, the mu neutrino and tau neutrino are maximally and ``rapidly'' mixed, this alone determines the mapping from current to mass eigenstates up to one rotation angle (theta) mixing the electron neutrino ``more slowly'', with an equal combination of the mu neutrino and tau neutrino. For sin 2 theta = 1, the resulti

Ulysses J. Sofia, Edward L. Fitzpatrick, David M. Meyer

We have reanalyzed the Goddard High Resolution Spectrograph data set presented by Snow et al. which contains the interstellar intersystem C II] 2325A line through the translucent cloud toward HD 24534 (X Persei). In contrast to the results of Snow et al., we clearly detect the C II] feature at the 3-sigma confidence level and measure a C^+ column density of

K. Bering

We consider a general formalism for treating a Hamiltonian (canonical) field theory with a spatial boundary. In this formalism essentially all functionals are differentiable from the very beginning and hence no improvement terms are needed. We introduce a new Poisson bracket which differs from the usual ``bulk'' Poisson bracket with a boundary term and show

E. J. Barton, R. R. de Carvalho, M. J. Geller

Redshift Survey Compact Groups (RSCGs) are tight knots of N >= 3 galaxies selected from the CfA2+SSRS2 redshift survey. The selection is based on physical extent and association in redshift space alone. We measured 300 new redshifts of fainter galaxies within 1 h^{-1} Mpc of 14 RSCGs to explore the relationship between RSCGs and their environments. 13 of 14

J. R. Pelaez

We study the temperature evolution of the quark-antiquark condensate below the chiral phase transition. The hadronic gas is described using a virial expansion within Generalized Chiral Perturbation Theory. In such way, we can implement both the large or small chiral condensate scenarios and analyze the condensate dependence on the values of the lightest quar

R. P. Thun, S. McKee

We suggest that the atmospheric neutrino anomaly observed in the Super-Kamiokande (and other) experiments results from the combined effects of muon-neutrino to tau-neutrino oscillations with a Delta m^2 value of approximately 0.4 eV^2 and oscillations between muon neutrinos and electron neutrinos (and vice-versa) with 0.0001 < Delta m^2 < 0.001 eV^2. With an

Richard A. Wade, Ivan Hubeny

We present a large grid of computed far- and mid-ultraviolet spectra (850 Angstroms to 2000 Angstroms) of the integrated light from steady-state accretion disks in luminous cataclysmic variables. The spectra are tabulated at 0.25 Angstrom intervals with an adopted FWHM resolution of 1.0 Angstrom, so they are suitable for use with observed spectra from a vari

Adam F. Falk

I discuss the effect of final state interactions on the determination of the CKM angle \gamma from B -> K + pi decays. Using a simple Regge-based model for rescattering processes, I argue that such effects could be substantial enough to make it problematic to obtain reliable limits on \gamma in this way. Fortunately, an analysis of B -> K + K decays may prov

A. Vidiella-Barranco, J. A. Roversi

We construct a Hamiltonian for the generation of arbitrary pure states of the quantized electromagnetic field. The proposition is based upon the fact that a unitary transformation for the generation of number states has been already found. The general unitary transformation here obtained, would allow the use of nonlinear interactions for the production of pu

Klaus Geiger, Ron Longacre, Dinesh K. Srivastava

VNI is a general-purpose Monte-Carlo event-generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme, as well as the development of hadron cascades after h

G. P. Korchemsky

We show that the leading power corrections to the event shape distributions can be resummed into nonperturbative shape functions that do not depend on the center-of-mass energy and measure the energy flow in the final state. In the case of the thrust variable, the distribution is given by the convolution of the perturbative spectrum with the shape function.

Ganpathy Murthy, R. Shankar

We analytically calculate gaps for the 1/3, 2/5, and 3/7 polarized and partially polarized Fractional Quantum Hall states based on the Hamiltonian Chern-Simons theory we have developed. For a class of potentials that are soft at high momenta (due to the finite thickness of the sample) we find good agreement with numerical and experimental results.

L. Frankfurt, M. Strikman

We outline theoretical ideas on the soft and hard dynamics of strong high-energy interactions and discuss promising directions for future high-energy experimental investigations including the ones which would allow one to reveal the three-dimensional structure of QCD bound states, investigate the onset of regime of large parton densities, and observe the vio

Daniel W. Weedman, Jeffrey B. Wolovitz, Matthew A. Bershady, Donald P. Schneider

Observations in the rest frame ultraviolet from various space missions are used to define the nearby starburst regions having the highest surface brightness on scales of several hundred pc. The bright limit is found to be 6x10^-16 ergs/cm^2-s-A-arcsec^2 for rest frame wavelength of 1830 A. Surface brightness in the brightest pixel is measured for 18 galaxies

L. Frankfurt, A. Freund, M. Strikman

We demonstrate that the measurement of an azimuthal angle asymmetry in deeply virtual Compton scattering (DVCS) at HERA energies, is experimentally feasible and allows one to determine for the first time the ratio $\eta$, of the real to imaginary part of the DIS amplitude. We further show that such a measurement would discriminate between different scenarios

P. M. Garnavich, S. Jha, P. Challis, A. Clocchiatti

We use Type Ia supernovae studied by the High-Z Supernova Search Team to constrain the properties of an energy component which may have contributed to accelerating the cosmic expansion. We find that for a flat geometry the equation of state parameter for the unknown component, alpha_x=P_x/rho_x, must be less than -0.55 (95% confidence) for any value of Omega

J. Kisker, H. Rieger

We study the three-dimensional gauge glass model in the limit of strong screening by using a minimum cost flow algorithm, enabling us to obtain EXACT ground states for systems of linear size L<=48. By calculating the domain-wall energy, we obtain the stiffness exponent theta = -0.95+/-0.03, indicating the absence of a finite temperature phase transition, and

Zhaohui Shang, Zhongyuan Zheng, Elias Brinks, Jiansheng Chen

The edge-on, nearby spiral galaxy NGC5907 has long been used as the prototype of a ``non-interacting'' warped galaxy. We report here the discovery of two interactions with companion dwarf galaxies that substantially change this picture. First, a faint ring structure is discovered around this galaxy that is likely due to the tidal disruption of a companion dw

A. I. Davydychev, R. Delbourgo

A connection between one-loop $N$-point Feynman diagrams and certain geometrical quantities in non-Euclidean geometry is discussed. A geometrical way to calculate the corresponding Feynman integrals is considered. (This paper contains a brief review of the results presented in hep-th/9709216).

George Sterman

I give a pedagogical introduction to resummation and power corrections, using the thrust variable in electron-positron annihilation as an example, followed by an discussion of issues of predictability in perturbative QCD.

I. I. Mazin, D. J. Singh, Claudia Ambrosch-Draxl

The electronic structure of CrO_2 is critically discussed in terms of the relation of existing experimental data and well converged LSDA and GGA calculations of the electronic structure and transport properties of this half metal magnet, with a particular emphasis on optical properties. We find only moderate manifestations of many body effects. Renormalizati

C. G. Torre

A midi-superspace model is a field theory obtained by symmetry reduction of a parent gravitational theory. Such models have proven useful for exploring the classical and quantum dynamics of the gravitational field. I present 3 recent classes of results pertinent to canonical quantization of vacuum general relativity in the context of midi-superspace models.

T. J. Turner, I. M. George, K. Nandra

We discuss the hard X-ray properties of the Seyfert galaxy Ton S 180, based upon the analysis of ASCA data. We find the X-ray flux varied by a factor ~2 on a time scale of a few thousand seconds. The source showed significantly higher amplitude of variability in the 0.5-2 keV band than in the 2-10 keV band. The continuum is adequately parameterized as a Gamm

Alfredo Herrera-Aguilar, Oleg Kechkin

We derive a set of complex potentials which linearize the action of charging symmetries of the stationary Einstein-Maxwell dilaton-axion theory.

Joseph A. Minahan

We construct the duality groups for N=2 Supersymmetric QCD with gauge group SU(2n+1) and N_f=4n+2 hypermultiplets in the fundamental representation. The groups are generated by two elements $S$ and $T$ that satisfy a relation $(STS^{-1}T)^{2n+1}=1$. Thus, the groups are not subgroups of $SL(2,Z)$. We also construct automorphic functions that map the fundamen

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

Ab-initio calculations have been used to study the influence of the interface morphology and, notably, of the exchange reaction on the electronic properties of Al/GaN (100) interfaces. In particular, the effects of interface structure (i.e. interfacial bond lengths, semiconductor surface polarity, and reacted intralayers) on the SBH at the Al/GaN (001) junct

Carlo Rovelli

We construct the operator that projects on the physical states in loop quantum gravity. To this aim, we consider a diffeomorphism invariant functional integral over scalar functions. The construction defines a covariant, Feynman-like, spacetime formalism for quantum gravity and relates this theory to the spin foam models. We also discuss how expectation valu

I. M. George, R. F. Mushotzky, T. J. Turner, T. Yaqoob

(Abridged) We present the results from {\it ASCA} observations of NGC 3227 along with those from a {\it ROSAT} observation. The 0.6--10 keV continuum is consistent with a powerlaw with $\Gamma \sim 1.6$, flatter than that typically observed in Seyfert galaxies. Fe $K$-shell emission is observed with an EW and profile typical of Seyfert 1 galaxies. The {\it A

Alexander Kusenko

MSSM predicts the existence of Q-balls, some of which can be entirely stable. Both stable and unstable Q-balls can play an important role in cosmology. In particular, Affleck-Dine baryogenesis can result in a copious production of stable baryonic Q-balls, which can presently exist as a form of dark matter.

Wayne A. Tokaruk, T. C. A. Molteno, Stephen W. Morris

We describe experiments on B{\'e}nard-Marangoni convection in horizontal layers of two immiscible liquids. Unlike previous experiments, which used gases as the upper fluid, we find a square planform close to onset which undergoes a secondary bifurcation to rolls at higher temperature differences. The scale of the convection pattern is that of the thinner low

P. Mazzotta, G. Mazzitelli, S. Colafrancesco, N. Vittorio

We present in this paper new and updated calculations of the ionization equilibrium for all the elements from H to Ni. We collected for these elements all the data available in the literature for the ionization and radiative plus dielectronic recombination rates. In particular, the dielectronic rates have been fitted with a single formula and the related coe

Mrinal Dasgupta

This talk discusses the power behaved corrections to fragmentation functions for the current jet in non-singlet deep inelastic scattering. These corrections are estimated by means of a renormalon model using a dispersive approach. The assumption of a universal infrared finite coupling enables us to provide quantitative estimates.

K. Odagiri

The colour connection structure of QCD ($2\to2$) processes is discussed, with emphasis on its application to the supersymmetric 2 parton $\to$ 2 sparton processes, which are currently being implemented in the HERWIG Monte Carlo event generator. The procedure described by Marchesini and Webber is found to be inadequate, and a new method is proposed. However,

A. N. Schellekens

For each $N$ an infinite number of Conformal Field Theories is presented that has the same fusion rules as SO(N) level 2. These new theories are obtained as extensions of the chiral algebra of $SO(NM^2)$ level 2, and correspond to new modular invariant partition functions of these theories.

Gianluca Oderda, George Sterman

When rapidity gaps in high-$p_T$ dijet events are identified by energy flow in the central region, they may be calculated from factorized cross sections in perturbative QCD, up to corrections that behave as inverse powers of the central region energy. Although power-suppressed corrections may be important, a perturbative calculation of dijet rapidity gaps in

Merced Montesinos, Carlo Rovelli

The role of fermionic matter in the spectrum of the area operator is analyzed using the Baez--Krasnov framework for quantum fermions and gravity. The result is that the fermionic contribution to the area of a surface $S$ is equivalent to the contribution of purely gravitational spin network's edges tangent to $S$. Therefore, the spectrum of the area operator

Jens O. Andersen, Eric Braaten

In the mean-field approximation, a trapped Bose-Einstein condensate at zero temperature is described by the Gross-Pitaevskii equation for the condensate, or equivalently, by the hydrodynamic equations for the number density and the current density. These equations receive corrections from quantum field fluctuations around the mean field. We calculate the sem

Jorge Pullin

This is a summary of a talk delivered at the workshop ``Quantum gravity in the Southern Cone II''. We present a very brief review of current results on canonical quantization of general relativity using Ashtekar's variables and loop quantization.

Michael Creutz

I discuss a simple numerical algorithm for the direct evaluation of multiple Grassmann integrals. The approach is exact, suffers no Fermion sign problems, and allows arbitrarily complicated interactions. Memory requirements grow exponentially with the interaction range and the transverse size of the system. Low dimensional systems of order a thousand Grassma

S. A. Grigera, E. Morre, E. Osquiguil, C. Balseiro

Using an extensive scaling analysis of the transport properties in twinned YBaCuO(123) crystals we have experimentally found the predicted change in the universality class of the Bose-glass to liquid transition when the magnetic field is applied at small angles away from the direction of the correlated defects. The new dynamical critical exponent is s'=1.1 +

G. L. H. Harris, G. B. Poole, W. E. Harris

The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for a large sample of stars in the outer halo of the giant elliptical NGC 5128 (d = 4 Mpc). The globular cluster N5128-C44, at the center of the Planetary Camera field, is well enough resolved to permit the construction of a color-magnitude diagram (CMD) for it which covers the brighte

S. A. Rinehart, T. L. Hayward, J. R. Houck

We have imaged the M2Iab supergiant star Alpha Ori at 11.7 micron and 17.9 micron using the Hale 5-m telescope and an array camera with sub-arcsecond angular resolution. Our images reveal the circumstellar dust shell extending out to approximately 5" from the star. By fitting two multi-parameter models to the data, we find values for the dust shell inner rad

Jeongwon Ho, Gungwon Kang

We have considered the divergence structure in the brick-wall model for the statistical mechanical entropy of a quantum field in thermal equilibrium with a black hole which {\it rotates}. Especially, the contribution to entropy from superradiant modes is carefully incorporated, leading to a result for this contribution which corrects some previous errors in

K. Iwamoto, P. A. Mazzali, K. Nomoto, H. Umeda

The discovery of the peculiar supernova (SN) 1998bw and its possible association with the gamma-ray burst (GRB) 980425$^{1,2,3}$ provide new clues to the understanding of the explosion mechanism of very massive stars and to the origin of some classes of gamma-ray bursts. Its spectra indicate that SN~1998bw is a type Ic supernova$^{3,4}$, but its peak luminos

J. Bonca, J. E. Gubernatis

We studied the effects of hole doping on spin correlations in the periodic Anderson model, mainly at the full and three-quarters-full lower bands cases. In the full lower band case, strong anti-ferromagnetic correlations develop when the on-site repulsive interaction strength $U$ becomes comparable to the quasi-particle band width. In the three-quarters full

Kamiokande Collaboration, S. Hatakeyama

The flux of upward through-going muons of minimum (mean) threshold energy > 1.6 (3.0) GeV is measured, based on a total of 372 events observed by the Kamiokande II+III detector during 2456 detector live days. The observed muon flux was (1.94+-0.10(stat.)+0.07-0.06(sys.))*10^-13 /cm^2/s/sr, which is compared to an expected value of (2.46+-0.54(theo.))*10^-13/

A. Hazareesing, M. Mezard

We reconsider the problem of the solid-liquid-vapour contact-line on a disordered substrate, in the collective pinning regime. We go beyond scaling arguments and perform an analytic computation, through the replica variational method, of the fluctuations of the line. We show how gravity effects must be included for a proper quantitative comparison with avail

A. Ringwald, F. Schrempp

We present our results for inclusive instanton-induced cross-sections in deep-inelastic scattering, paying in particular attention to the residual renormalization-scale dependencies. A ``fiducial'' kinematical region in the relevant Bjorken variables is extracted from recent lattice simulations of QCD. The integrated instanton-contribution to the cross-secti

S. Seide, C. Wetterich

We discuss first order transitions for systems in the Ising universality class. The critical long distance physics near the endpoint of the critical line is explicitly connected to microscopic properties of a given system. Information about the short distance physics can therefore be extracted from the precise location of the endpoint and non-universal ampli

L. Stanghellini, J. C. Blades, S. J. Osmer, M. J. Barlow

The morphology of planetary nebulae (PNe) provides an essential tool for understanding their origin and evolution, as it reflects both the dynamics of the gas ejected during the TP-AGB phase, and the central star energetics. Here we study the morphology of 27 Magellanic Cloud planetary nebulae (MCPNe) and present an analysis of their physical characteristics

Jean-Philippe Uzan

When the topology of the universe is non trivial, it has been shown that there are constraints on the network of domain walls, cosmic strings and monopoles. I generalize these results to textures and study the cosmological implications of such constraints. I conclude that a large class of multi-connected universes with topological defects accounting for stru

MP Hobson, AW Jones, AN Lasenby, FR Bouchet

A maximum entropy method (MEM) is presented for separating the emission due to different foreground components from simulated satellite observations of the cosmic microwave background radiation (CMBR). In particular, the method is applied to simulated observations by the proposed Planck Surveyor satellite. The simulations, performed by Bouchet and Gispert (1

A. M. Koekemoer, C. P. O'Dea, S. A. Baum, C. L. Sarazin

We present results from an extensive HST spectroscopic search for UV absorption lines in the spectrum of the quasar B2~1028+313, which is associated with the central dominant galaxy in the cluster Abell~1030 ($z=0.178$). This is one of the brightest known UV continuum sources located in a cluster, and therefore provides an ideal opportunity to obtain stringe

Alexander Gorokhovsky

In this article we construct explicit cocycles in the Alexander-Spanier cohomological complex, representing the Chern character of an element in K-theory.

T. Engeland, M. Hjorth-Jensen, A. Holt, E. Osnes

We describe the properties of complex nuclei, such as the Sn isotopes with mass numbers A = 100 - 132, in terms of the free nucleon--nucleon interaction as obtained from meson--exchange theory. This amounts to first calculating an effective interaction in which the free interaction is modified by the presence of the appropriate nuclear medium. The short--ran

R. Cassia-Moura, A. Popescu

The activation kinetics of the ion channels formed by colicin Ia incorporated into a planar bilayer lipid membrane (BLM) was investigated by the voltage clamp technique using different step voltage stimuli. The temporal behaviour of ion channels put in evidence a gain or a loss of memory, revealed by a specific sequence of electrical pulses used for stimulat

John S. Arabadjis, Joel N. Bregman

We study the column densities of neutral atomic, molecular, and warm ionized Galactic gas through their continuous absorption of extragalactic X-ray spectra at |b| > 25 degrees. For N(H,21cm) < 5x10^20 cm^-2 there is an extremely tight relationship between N(H,21cm) and the X-ray absorption column, N(xray), with a mean ratio along 26 lines of sight of N(xray

M. Fritz, T. Hezel, M. Homscheidt, H. O. Moser

A prototype of a novel superconductive undulator with a period length of 3.8 mm is described. The undulator is 100 periods long. In the first tests described in this paper the undulator was cooled in a helium bath and it was shown that it can be operated as expected with a maximum current of 1400 A. Afterwards the undulator field was measured with a miniatur

C. Martinez Ontalba, J. Munoz Masque, A. Valdes

The moduli space of jets of certain G-structures (basically those which admit a canonical linear connection) is shown to be isomorphic to the quotient of a natural G-module by G.

Philippe Eyssidieux

Inspired by some recent work of M. Farber, W. L\"uck and M. Shubin on L2 homotopy invariants of infinite Galois coverings of simplicial complexes (L2 Betti numbers and Novikov-Shubin invariants), this article extends Atiyah's L2 index theory to coherent analytic sheaves on complex analytic spaces. Let $X$ be a complex analytic space with a proper cocompact b

Qiang Zhao, Zhenping Li, C. Bennhold

A quark model approach to the photoproduction of vector mesons off nucleons is proposed. Its starting point is an effective Lagrangian of the interaction between the vector meson and the quarks inside the baryon, which generates the non-diffractive s- and u- channel resonance contributions. Additional t-channel $\pi^0$ and $\sigma$ exchanges are included for

Peter Fulde, Stefan Kettemann

The spin flip of the conduction electrons at the interface of a ferromagnetic and a nonmagnetic part of a metallic wire, suspended between two electrodes, is shown to tort the wire when a current is driven through it. In order to enhance the effect it is suggested to use an alternating current in resonance with the torsional oscillations. Thereby the magneti

G. Damm, W. Kerler

We investigate four-dimensional compact U(1) lattice gauge theory with a monopole term added to the Wilson action. First we consider the phase structure at negative $\beta$, revealing some properties of a third phase region there, in particular the existence of a number of different states. Then our present studies concentrate on larger values of the monopol

EROS collaboration

We report on intensive photometric monitoring on 18 June 1998 of MACHO SMC-98-1, a binary-lens microlensing event seen toward the Small Magellanic Cloud (SMC). The observations cover 5.3 hours (UT 5:17 -- 10:37), and show a sharp drop of 1.8 mag during the first 1.8 hours, followed by an abrupt flattening at UT 7:08 +- 0:02. We interpret the kink at 7:08 as

B. Ziaja

The structure of the QCD gluonic cascade in configuration space is investigated. The explicit form of the inclusive single particle density in configuration space transverse coordinates is derived in the double logarithmic approximation (DLA) of QCD. The possible simplification of the multiparton density matrix formalism for DLA approach is found and discuss

J. Ambjorn, J. L. Nielsen, J. Rolf, R. Loll

No theory of four-dimensional quantum gravity exists as yet. In this situation the two-dimensional theory, which can be analyzed by conventional field-theoretical methods, can serve as a toy model for studying some aspects of quantum gravity. It represents one of the rare settings in a quantum-gravitational context where one can calculate quantities truly in

A. Borowiec, M. Francaviglia

We shall use the variational decomposition technique in order to calculate equations of motion and Noether energy-momentum complex for some classes of non-linear gravitational Lagrangians within the first-order (Palatini) formalism. In particular, a complex space-time appears as a solution of our variational problem.

Yi-hong Gao, Wei Zhang

By using the D0-brane cluster picture, we consider the Hawking radiation of Schwarszchild black hole (SBH) in large N Matrix model. We get the correct formula for the the Hawing evaporation rate. Our results give some evidence on the Lorentz invariance of the physics of Matrix model.

Nikolaos Kidonakis, Ramona Vogt

We discuss the heavy quark production cross section near partonic threshold in hadronic collisions, including the resummation of leading and next-to-leading logarithms arising from soft gluon emission. We show how to handle the complications due to the non-universal non-leading logarithms. We give analytical results for the $q {\bar q}$ partonic subprocess a

Dan Radu Grigore

We generalise a result of Aste and Scharf saying that, under some reasonable assumptions, consistent with renormalisation theory, the non-Abelian gauge theories describes the only possibility of coupling the gluons. The proof is done using Epstein-Glaser approach to renormalisation theory.

P. A. Horváthy, J. -C. Yéra

The cubic non-linear Schr\"odinger equation (NLS), where the coefficient of the non-linear term can be a function $F(t,x)$, is shown to pass the Painlev\'e test of Weiss, Tabor, and Carnevale only for $F=(a+bt)^{-1}$, where $a$ and $b$ constants. This is explained by transforming the time-dependent system into the ordinary NLS (with $F=\const$.) by means of

J. Ambjorn, M. Carfora, D. Gabrielli, A. Marzuoli

This is an expanded and revised version of our geometrical analysis of the strong coupling phase of 4D simplicial quantum gravity. The main differences with respect to the former version is a full discussion of singular triangulations with singular vertices connected by a subsingular edge. In particular we provide analytical arguments which characterize the

Saumen Datta, Sourendu Gupta

We studied screening masses in the equilibrium thermodynamics of SU(2) and SU(3) pure gauge theories on the lattice. At a temperature of 2 Tc we found strong evidence for dimensional reduction in the non-perturbative spectrum of screening masses. Mass ratios in the high temperature SU(3) theory are consistent with those in the pure gauge theory in three dime

Chandrashekar Devchand, Jean Nuyts

Lorentz covariant generalisations of the notions of supersymmetry, superspace and self-duality are discussed. The essential idea is to extend standard constructions by allowing tangent vectors and coordinates which transform according to more general Lorentz representations than solely the spinorial and vectorial ones of standard lore. Such superspaces provi

Yi-hong Gao, Wei Zhang

D0-brane gas picture of Schwarzschild black hole (SBH) is considered in the large N regime of Matrix theory. An entropy formula, which reproduces the thermodynamics of SBH in the large N limit for all dimensions ($D\geq 6$), is proposed. The equations of states for low temperature are obtained. We also give a proof of the Newton gravitation law between two S

P. Azaria, P. Lecheminant, A. A. Nersesyan

We study a model of three $S=1/2$ antiferromagnetic Heisenberg spin chains weakly coupled by on-rung and plaquette-diagonal interchain interactions. It is shown that the model exhibits a critical phase with central charge C=2 and belongs to the class of ``chirally stabilized'' liquids recently introduced by Andrei, Douglas, and Jerez. By allowing anisotropic

Wladyslaw Marcinek

Some problems related to an algebraic approach to quantum statistics are discussed. Generalized quantum statistics is described as a result of interactions. The Fock space representation is discussed. The problem of existence of well--defined scalar product is considered. An example of physical effect in system with generalized statistics is also given.

Stefan Kettemann

The autocorrelation function of spectral determinants (ASD) is used to characterize the discrete spectrum of a phase coherent quasi- 1- dimensional, disordered wire as a function of its length L in a finite, weak magnetic field. An analytical function is obtained depending only on the dimensionless conductance g= xi/L where xi is the localization length, the

Tetsuya Shiromizu

We investigate phase transitions due to excited Q-balls. As excited Q-balls have angular momentum, a magnetic field can be generated if one considers gauged Q-balls. Based on the course of the phase transition we estimate the strength of the magnetic field and then we find that it might be the origin of observed magnetic fields of astrophysical objects such

H. Hirashita, T. T. Takeuchi, N. Tamura

We discuss a physical interpretation of the relation between $M_{\rm vir}/L$ and $M_{\rm vir}$ of dwarf spheroidal galaxies (dSphs), where $M_{\rm vir}$ and $L$ are the virial mass and the total luminosity of a dSph, respectively. We used 11 dSphs in the Local Group as the sample. We find two distinct sequences on the $M_{\rm vir}/L$--$M_{\rm vir}$ plane: $M

Marc-Thierry Jaekel, Serge Reynaud

We define quantum observables associated with Einstein localisation in space-time. These observables are built on Poincare' and dilatation generators. Their commutators are given by spin observables defined from the same symmetry generators. Their shifts under transformations to uniformly accelerated frames are evaluated through algebraic computations in con

Robert Harlander

Recent developments in the field of automatic computation of Feynman diagrams using asymptotic expansions are reviewed. The hadronic decay rate of the Z-boson is taken as an example for their physical application.

A. D. Popov

It is well known that rational 2D conformal field theories are connected with Chern-Simons theories defined on 3D real manifolds. We consider holomorphic analogues of Chern-Simons theories defined on 3D complex manifolds (six real dimensions) and describe 4D conformal field theories connected with them. All these models are integrable. We describe analogues

C. J. Hamer, Zheng Weihong, J. Oitmaa

We study one and two hole properties of the t-J model at half-filling on the square lattice using series expansion methods at T=0. The dispersion curve for one hole excitations is calculated and found to be qualitatively similar to that obtained by other methods, but the bandwidth for small $t/J$ is some 20% larger than given previously. We also obtain the b

Miao Li, Tamiaki Yoneya

We briefly review the present status of string theory from the viewpoint of its implications on the short-distance space-time structure and black hole physics. Special emphases are given on two closely related issues in recent developments towards nonperturbative string theory, namely, the role of the space-time uncertainty relation as a qualitative but univ

Jung Kon Kim, Sang Pyo Kim

By using the invariant method we find one-parameter squeezed Gaussian states for both time-independent and time-dependent oscillators. The squeezing parameter is expressed in terms of energy expectation value for time-independent case and represents the degree of mixing positive and negative frequency solutions for time-dependent case. A {\it minimum uncerta

Mahn-Soo Choi, M. Y. Choi, Taeseung Choi, Sung-Ik Lee

We investigate the quantum phase transitions in two capacitively coupled chains of ultra-small Josephson-junctions, with emphasis on the external charge effects. The particle-hole symmetry of the system is broken by the gate voltage applied to each superconducting island, and the resulting induced charge introduces frustration to the system. Near the maximal

Mahn-Soo Choi, M. Y. Choi, Sung-Ik Lee

We consider arrays of Josephson junctions as well as single junctions in both the classical and quantum-mechanical regimes, and examine the generalized (frequency-dependent) resistance, which describes the dynamic responses of such Josephson-junction systems to external currents. It is shown that the generalized resistance and the power spectrum of voltage f

V. V. Kiselev

A model is constructed for a chiral abelian gauge-interaction of fermions and a potential of three higgses, so that the potential possesses a discrete symmetry of the vacuum state, which provides the introduction of three generations for the fermions. For the model including charged currents, a matrix of the flavor mixing is described, and a phase giving the

Daijiro Yoshioka

It has been clarified that charged excitation known as a skyrmion exists around the ferromagnetic ground state at the Landau level filling factor $\nu=1/q$, where $q$ is an odd integer. An infinite sized skyrmion is realized in the absence of the spin-Zeeman splitting or for double-layered systems. Analytical form of the wave function is identified at $\nu=1

Anton Kapustin

D-branes can end on orbifold planes if the action of the orbifold group includes (-1)^{F_L}. We consider configurations of D-branes ending on such orbifolds and study the low-energy theory on their worldvolume. We apply our results to gauge theories with eight supercharges in three and four dimensions. We explain how mirror symmetry for N=4 d=3 gauge theorie

Huai-Dong Cao, Jian Zhou

We define quantum exterior product wedge_h and quantum exterior differential d_h on Poisson manifolds, of which symplectic manifolds are an important class of examples. Quantum de Rham cohomology is defined as the cohomology of d_h. We also define quantum Dolbeault cohomology. Quantum hard Lefschetz theorem is proved. We also define a version of quantum inte

Alexander Gorokhovsky

We derive simple explicit formulas for the character of a cycle in the Connes' (b,B)-bicomplex of cyclic cohomology and give applications to the Fredholm modules and equivariant characteristic classes.

Wei-Jing Zhu, Christopher L. Henley

We have built an ab-initio LDA energy database with over 60 hypothetical extended structures of pure Boron, in each of which the coordination environment of each atom is equivalent. Focusing on eleven 6-coordinated structures, which are most relevant to the observed Boron phases, we deduce a nearest-neighbor-only 2-body interaction, refined by potentials tha