April 1996 arXiv papers — page 3

Jacques Bouaud, Bruno Bachimont, Pierre Zweigenbaum

We address here the treatment of metonymic expressions from a knowledge representation perspective, that is, in the context of a text understanding system which aims to build a conceptual representation from texts according to a domain model expressed in a knowledge representation formalism. We focus in this paper on the part of the semantic analyser which d

H. O. Jeschke, M. E. Garcia, K. H Bennemann

Combining an electronic theory with molecular dynamics simulations we present results for the ultrafast structural changes in small clusters. We determine the time scale for the change from the linear to a triangular structure after the photodetachment process Ag$_3^- \rightarrow {\rm Ag}_3$. We show that the time-dependent change of the ionization potential

Holger R. Dullin

We present a method to enlarge the phase space of a canonical Hamiltonian System in order to remove coordinate singularities arising from a nontrivial topology of the configuration space. This ``inflation'' preserves the canonical structure of the system and generates new constants of motion that realize the constraints. As a first illustrative examp

W. N. Brandt, J. P. Halpern, K. Iwasawa

The nearby barred spiral galaxy NGC 1672 is thought to have a weak Seyfert nucleus in addition to its strong starburst activity. Observations with the PSPC and HRI instruments on board the ROSAT X-ray satellite show that three X-ray sources with luminosities (1--2)\times 10^{40} erg/s are clearly identified with NGC 1672. The strongest X-ray source lies at t

Sidney van den Bergh, Roberto Abraham, Richard Ellis Nial Tanvir, Basilio Santiago

We present a catalog of morphological and color data for galaxies with $I < 25$ mag in the {\em Hubble Deep Field} (Williams et al. 1996). Galaxies have been inspected and (when possible) independently visually classified on the MDS and DDO systems. Measurements of central concentration and asymmetry are also included in the catalog. The fraction of interact

Thierry Foglizzo, Maximilian Ruffert

We prove that the sonic surface of axisymmetric meridional stationary flows is always attached to the accretor, however small, if the adiabatic index of the gas is gamma=5/3. Using local expansions near a point-like accretor, we extend Bondi&#39;s classification of spherically symmetric flows to axisymmetric flows, introducing the possibility of angular sect

T. J. Bridges, D. Carter, W. E. Harris, C. J. Pritchet

We have analysed new R-band photometry of globular clusters in NGC 6166, the cD galaxy in the cooling flow cluster A2199. In combination with the earlier B photometry of Pritchet \& Harris (1990), we obtain B$-$R colours for $\sim$ 40 globular clusters in NGC 6166. The mean B$-$R is 1.26 $\pm$ 0.11, corresponding to a mean [Fe/H] = $-$1 $\pm$ 0.4. Given that

J. J. Dalcanton, S. A. Shectman

Deep HST WFPC2 images have revealed a population of very narrow blue galaxies which Cowie et al. (1996) have interpreted as being a new morphological class of intrinsically linear star forming galaxies at $z=0.5-3$. We show that the same population exists in large numbers at low redshifts (z=0.03) and are actually the edge-on manifestation of low surface bri

Isaac L. Chuang, Yoshihisa Yamamoto

The construction of large, coherent quantum systems necessary for quantum computation remains an entreating but elusive goal, due to the ubiquitous nature of decoherence. Recent progress in quantum error correction schemes have given new hope to this field, but thus far, the codes presented in the literature assume a restricted number of errors and error fre

Stuart Samuel

An approximate vacuum wave functional $Ψ_0$ is proposed for $2+1$-dimensional Yang-Mills theories. Using $Ψ_0$, one can compute the $0^{++}$ glueball mass $M_G$ in terms of the string tension. By using the idea of dimensional reduction, a prediction for $M_G$ can be made in $3+1$ dimensions. One finds $M_G \approx 1.5$ GeV.

Robert D. Pisarski, Michel Tytgat

For an exact chiral symmetry which is spontaneously broken at zero temperature, we show that at nonzero temperature, generally pions travel at {\it less} than the speed of light. This effect first appears at next to leading order in an expansion about low temperature. When the chiral symmetry is approximate we obtain two formulas, like that of Gell-Mann, Oak

A. L. B. Ribeiro, R. R. de Carvalho, R. Coziol, H. V. Capelato

In the course of an extensive campaign to measure radial velocities of galaxies in a selected sample of compact groups photometrically studied by de Carvalho et al. (1994), we report the discovery of a system very rich in starburst galaxies and AGNs. This is the system HCG 16 of Hickson&#39;s (1982) catalog of CGs. The 7 brightest galaxies form a kinematical

Alexis Kouvidakis

In this note we examine the question of expressing the determinant of the push forward of a symmetric line bundle on an abelian fibration in terms of the pull back of the relative dualizing sheaf via the zero section.

Anne Schilling, S. Ole Warnaar

We propose a generalization of Bailey&#39;s lemma, useful for proving $q$-series identities. As an application, generalizations of Euler&#39;s identity, the Rogers-Ramanujan identities, and the Andrews-Gordon identities are derived. This generalized Bailey lemma also allows one to derive identities for the branching functions of higher-level $A^{(1)}_1$ cose

L. Bonora, S. Krivonos, A. Sorin

We formulate a conjecture for the three different Lax operators that describe the bosonic sectors of the three possible $N=2$ supersymmetric integrable hierarchies with $N=2$ super $W_n$ second hamiltonian structure. We check this conjecture in the simplest cases, then we verify it in general in one of the three possible supersymmetric extensions. To this en

Martin Z. Bazant, Efthimios Kaxiras

We provide a systematic test of empirical theories of covalent bonding in solids using an exact procedure to invert ab initio cohesive energy curves. By considering multiple structures of the same material, it is possible for the first time to test competing angular functions, expose inconsistencies in the basic assumption of a cluster expansion, and extract

J. Balog, M. Niedermaier, T. Hauer

The two-point functions of the energy-momentum tensor and the Noether current are used to probe the O(3) nonlinear sigma model in an energy range below 10^4 in units of the mass gap $m$. We argue that the form factor approach, with the form factor series trunctated at the 6-particle level, provides an almost exact solution of the model in this energy range.

Frederick T. Hawes, Anthony G. Williams, Craig D. Roberts

We extend a previous Landau-gauge study of subtractive renormalization of the fermion propagator Dyson-Schwinger equation (DSE) in strong-coupling, quenched QED_4 to arbitrary covariant gauges. We use the fermion-photon proper vertex proposed by Curtis and Pennington with an additional correction term included to compensate for the small gauge-dependence ind

Alok Kumar, Koushik Ray

Compactifications of M-theory to two dimensional space-time on ${(K3\times \T^5)}/ \Z_2$ and ${(K3\times K3\times §^1)}/ \Z_2$ orientifolds are presented. These orientifolds provide examples of anomaly free chiral supergravity models in two dimensions with (8, 0) and (4, 0) supersymmetries. Anomaly free spectra at the enhanced symmetry points are also obtain

ZEUS Collaboration

The production of $ϕ$ mesons in the reaction $e^{+}p \rightarrow e^{+} ϕp$ ($ϕ\rightarrow K^{+}K^{-}$), for $7 < Q^2 < 25$ GeV$^2$ and for virtual photon-proton centre of mass energies ($W$) in the range 42-134 GeV, has been studied with the ZEUS detector at HERA. When compared to lower energy data at similar $Q^2$, the results show that the $γ^*p \rightarro

Ram Brustein

Models of string cosmology predict a stochastic background of gravitational waves with a spectrum that is strongly tilted towards high frequencies. I give simple approximate expressions for spectral densities of the cosmic background which can be directly compared with sensitivities of gravitational wave detectors.

I. L. Buchbinder, A. Yu. Petrov

A new $N=1$ superfield model in $D=4$ flat superspace is suggested. This model describes dynamics of chiral compensator and can be treated as a low-energy limit of $D=4$, $N=1$ quantum superfield supergravity. Renormalization structure of this model is studied and one-loop counterterms are calculated. It is shown that the theory is infrared free. An effectiv

Fabian H. L. Essler, Holger Frahm, Alexander R. Its, Vladimir E. Korepin

We consider quantum correlation functions of the antiferromagnetic spin-$\frac{1}{2}$ Heisenberg XXZ spin chain in a magnetic field. We show that for a magnetic field close to the critical field $h_c$ (for the critical magnetic field the ground state is ferromagnetic) certain correlation functions can be expressed in terms of the solution of the Painlevé V t

Isaac L. Chuang, Yoshihisa Yamamoto

Decoherence and loss will limit the practicality of quantum cryptography and computing unless successful error correction techniques are developed. To this end, we have discovered a new scheme for perfectly detecting and rejecting the error caused by loss (amplitude damping to a reservoir at T=0), based on using a dual-rail representation of a quantum bit. T

Lior Goldenberg, Lev Vaidman

This is our Reply to Peres&#39; Comment [quant-ph/9509003] to &#34;Quantum Cryptography Based on Orthogonal States&#34; [Phys. Rev. Lett. 75, 1239 (1995)].

Adriano Barenco, Andre` Berthiaume, David Deutsch, Artur Ekert

We propose a method for the stabilisation of quantum computations (including quantum state storage). The method is based on the operation of projection into $\cal SYM$, the symmetric subspace of the full state space of $R$ redundant copies of the computer. We describe an efficient algorithm and quantum network effecting $\cal SYM$--projection and discuss the

Carsten Greiner, Dirk-Hermann Rischke

The particle density distribution emerging from the solution of the Vlasov equation for relativistic, non-interacting particles with spherically symmetric initial conditions is shown to exhibit a shell-like structure for late fixed times in the center-of-mass (CM) frame of the system. A similar phenomenon was recently observed employing the test-particle met

M. Batinic, A. Svarc, T. -S. H. Lee

The total cross section for the near threshold eta production in proton-proton collisions has been investigated with the assumption that the production mechanism is due to the emission of a meson x (pi, eta, sigma) from one of the nucleons followed by a x N --> eta N transition on the second one. The x N --> eta N amplitudes are generated from the unitary mu

V. S. Uma Maheswari, D. N. Basu, J. N. De, S. K. Samaddar

An equation of state(EOS) of nuclear matter with explicit inclusion of a spin-isospin dependent force is constructed from a finite range, momentum and density dependent effective interaction. This EOS is found to be in good agreement with those obtained from more sophisticated models for unpolarised nuclear matter. Introducing spin degrees of freedom, it is

Oe. Elgaroey, L. Engvik, M. Hjorth-Jensen, E. Osnes

In this work we present results for pairing gaps in $β$--stable neutron star matter with electrons and muons using a relativistic Dirac--Brueckner--Hartree--Fock approach, starting with modern meson--exchange models for the nucleon--nucleon interaction. Results are given for superconducting $^1S_0$ protons and $^3P_2$ and $^1D_2$ neutron superfluids. A compa

D. M. Gitman, S. D. Odintsov, Yu. I. Shil&#39;nov

The phase structure of $d=3$ Nambu-Jona-Lasinio model in curved spacetime with magnetic field is investigated in the leading order of the $1/N$-expansion and in linear curvature approximation (an external magnetic field is treated exactly). The possibility of the chiral symmetry breaking under the combined action of the external gravitational and magnetic fi

Romuald A. Janik

In this talk we present some links of the theory of the odderon with elliptic curves. These results were obtained in an earlier work \cite{RJ}. The natural degrees of freedom of the odderon turn out to coincide with conformal invariants of elliptic curves with a fixed `sign&#39;. This leads to a formulation of the odderon which is modular invariant with resp

Ivan G. Avramidi

We study the effective action in Euclidean Yang-Mills theory with a compact simple gauge group in one-loop approximation assuming a covariantly constant gauge field strength as a background. For groups of higher rank and spacetimes of higher dimensions such field configurations have many independent color components taking values in Cartan subalgebra and man

Howard Baer, Chih-hao Chen, Frank Paige, Xerxes tata

We use ISAJET to perform a detailed comparison of the supersymmetry reach of the current Tevatron (100~pb$^{-1}$) with that of the Main Injector (2~fb$^{-1}$) and the proposed TeV33 upgrade designed to yield an integrated luminosity of 25~fb$^{-1}$. Our analysis is performed within the framework of the minimal supergravity model with gauge coupling unificati

Dardo Píriz, Mou Roy, José Wudka

Neutrino oscillations in the presence of strong gravitational fields are studied. We look at very high energy neutrinos ($\sim $1 TeV) emanating from Active Galactic Nuclei (AGN). It is observed that spin flavor resonant transitions of such neutrinos may occur in the vicinity of AGN due to {\it gravitational} effects and due to the presence of a large magnet

Wojciech Slominski, Jerzy Szwed

The QCD structure of the electroweak bosons is reviewed and the lepton structure function is defined and calculated. The leading order splitting functions of electron into quarks are extracted, showing an important contribution from $γ$-$Z$ interference. Leading logarithmic QCD evolution equations are constructed and solved in the asymptotic region where log

Nobuchika Okada

We examine the `singlet majoron model&#39; first introduced by Chikashige, Mohapatra and Peccei as a simple extension of the standard model with massive Majorana neutrinos. We can explain both the solar and the atmospheric neutrino deficits by the oscillations between electroweak doublet and singlet neutrinos without flavor mixing. Furthermore, while some li

S. F. King

We suggest that the anomalous 4-jet events recently reported by ALEPH may be the first indication of low scale technicolour. According to our interpretation about half of the events are due to resonantly enhanced pair production of charged technipions, of mass around 55 GeV, each decaying into a pair of jets, the other half being due to standard processes. T

Iring Bender, Dieter Gromes

Embedding the lattice gauge theory into a continuum theory allows to use the continuum action as trial action in the variational calculation. Only originally divergent graphs contribute. This leads to a very simple scheme which makes it possible to write down explicit expressions for the plaquette energy $E$ for U(1) in arbitrary space time dimension for the

O. M. Bulashenko, V. A. Kochelap, L. L. Bonilla

Electron scattering on a thin layer where the potential depends self-consistently on the wave function has been studied. When the amplitude of the incident wave exceeds a certain threshold, a soliton-shaped brightening (darkening) appears on the layer causing diffraction of the wave. Thus the spontaneously formed transverse pattern can be viewed as a self-in

Susanne Klee, Alejandro Muramatsu

A field theory describing the low-energy, long-wavelength sector of an incommensurate, spiral magnetic phase is derived from a spin-fermion model that is commonly used as a microscopic model for high-temperature superconductors. After integrating out the fermions in a path-integral representation, a gradient expansion of the fermionic determinant is performe

A. E. Sikkema, W. J. L. Buyers, I. Affleck, J. Gan

We study the phase diagram of the Ising-Kondo lattice with transverse magnetic field as a possible model for the weak-moment heavy-fermion compound URu2Si2, in terms of two low-lying f singlets in which the uranium moment is coupled by on-site exchange to the conduction electron spins. In the mean-field approximation for an extended range of parameters, we s

George Anton Kiraz

This paper establishes a framework under which various aspects of prosodic morphology, such as templatic morphology and infixation, can be handled under two-level theory using an implemented multi-tape two-level model. The paper provides a new computational analysis of root-and-pattern morphology based on prosody.

Thilo Götz, Walt Detmar Meurers

Linguistic theories formulated in the architecture of {\sc hpsg} can be very precise and explicit since {\sc hpsg} provides a formally well-defined setup. However, when querying a faithful implementation of such an explicit theory, the large data structures specified can make it hard to see the relevant aspects of the reply given by the system. Furthermore,

H. C. Rosu, M. Reyes

We provide an analysis of the radial structure of TE and TM modes of the Maxwell fisheye lens, by means of Maxwell equations as applied to the fisheye case. Choosing a lens of size R = 1 cm, we plot some of the modes in the infrared range.

M. Hanasz, H. Sol

We investigate the Kelvin-Helmholtz instability of stratified jets. The internal component (core) is made of a relativistic gas moving with a relativistic bulk speed. The second component (sheath or envelope) flows between the core and external gas with a nonrelativistic speed. Such a two-component jet describes a variety of possible astrophysical jet config

M. S. Kowitt, E. S. Cheng, D. A. Cottingham, D. J. Fixsen

We report the characterization of bright, compact features in the cosmic microwave background radiation (CMBR) detected during the June 1992 and June 1994 balloon flights of the Medium Scale Anisotropy Measurement (MSAM1-92 and MSAM1-94, respectively). Spectral flux densities are determined for each feature at 5.7, 9.3, and 16.5 cm$^{-1}$. No viable counterp

Prasenjit Saha, Geoffrey V. Bicknell, Peter J. McGregor

We reanalyze published kinematic and photometric data for the cool star population in the central 10 pc (240 arcsec) of the Galaxy, while (a) isolating the photometric data appropriate to this population, and (b) properly allowing for projection effects. Under the assumptions that the system is spherical and isotropic, we find that M/L_K varies from <=1 outs

Kazuyuki Kanaya

I review the present status of nonperturbative studies on the nature of the finite temperature QCD transition on the lattice, with the special attention to the determination of the order of the transition. [Talk given at the International Symposium on {\it Origin of Matter and Evolution of Galaxies in the Universe}, Jan.\ 18 -- 20, 1996, Atami, Japan.]

Sangeeta Malhotra, David N Spergel, James E Rhoads, Jing Li

Using the near infrared fluxes of local galaxies derived from COBE/DIRBE J(1.25 $μ$m) K (2.2 $μ$m) \& L (3.5 $μ$m) band maps and published Cepheid distances, we construct Tully-Fisher (TF) diagrams for the nearby galaxies. The measured dispersions in these luminosity-linewidth diagrams are remarkably small: $σ_J = 0.09$ magnitudes, $σ_K = 0.13$ magnitudes, a

Mark Henriksen, Maxim Markevitch

We have analyzed spatially resolved spectra of A754 obtained with ASCA. The combination of spectral and imaging capabilities of ASCA has set unprecedented constraints on the hydrodynamical effects of a cluster merger. We find significant gas temperature variations over the cluster face, indicating shock heating of the atmosphere during the merger. The hottes

Maxim Markevitch

ASCA data are used to obtain two-dimensional gas temperature maps of A2256, A2319, A2163 and A665. In all four, the temperature decreases significantly at off-center distances of ~1 h^{-1} Mpc. Central regions of the two nearer clusters A2256 and A2319 appear largely isothermal except for the cooler spots coincident with the subunits in their X-ray surface b

Tetsu Kitayama, Yasushi Suto

Temperature and luminosity functions of X-ray clusters are computed semi-analytically, combining a simple model for the cluster gas properties with the distribution functions of halo formation epochs proposed by Lacey & Cole (1993) and Kitayama & Suto (1996). In contrast to several previous approaches which apply the Press--Schechter mass function in a strai

Patrick M. Gilmer

We show how one may sometimes perform singular ambient surgery on the complex locus of a real algebraic curve and obtain what we call a floppy curve. A floppy curve is a certain kind of singular surface in CP(2), more general than the complex locus of a real nodal curve. We derive analogs for floppy curves of known restrictions on real nodal curves. In parti

Gilad Lifschytz

We calculate the potential between two different stationary D-branes and the velocity dependent potential between two different moving D-branes. We identify configurations with some unbroken supersymmetry, using a zero force condition. The potentials are compared with an eleven dimensional calculation of the scattering of a zero black-brane from the $0,2,4$

S. Aid

A search for squarks of R-parity violating supersymmetry is performed in $ep$ collisions at HERA using H1 1994 $e^+$ data. Direct single production of squarks of each generation by $e^+$-quark fusion via a Yukawa coupling $λ&#39;$ is considered. All possible R-parity violating decays and gauge decays of the squarks are taken into account. No significant devi

Satya N. Majumdar, Clément Sire

We study the decay of the probability for a non-Markovian stationary Gaussian walker not to cross the origin up to time $t$. This result is then used to evaluate the fraction of spins that do not flip up to time $t$ in the zero temperature Monte-Carlo spin flip dynamics of the Ising model. Our results are compared to extensive numerical simulations.

D. Ebert, M. K. Volkov

Using recent data for the decays $f_0 \to γγ$, $f_0 \to ππ$, we determine the mixing angle of scalar mesons in a chiral quark $σ$-model. This value is employed to analyze of the kaon polarizability. It is shown that pole diagrams from intermediate scalar mesons and their mixing angle significantly affect the electromagnetic polarizability of charged and neut

Alexey A. Kadeishvili

Vertex operators for the deformed Virasoro algebra are defined, their bosonic representation is constructed and difference equation for the simplest vertex operators is described.

Takahiko Matsubara, Yasushi Suto

We propose cosmological redshift-space distortion of correlation functions of galaxies and quasars as a probe of both the density parameter $Ω_0$ and the cosmological constant $λ_0$. In particular, we show that redshift-space distortion of quasar correlation functions at $z\sim2$ can in principle set a constraint on the value of $λ_0$. This is in contrast to

Sanjay Jhingan, P. S. Joshi, T. P. Singh

Further to results in [9], pointing out the role of initial density and velocity distributions towards determining the final outcome of spherical dust collapse, the causal structure of singularity is examined here in terms of evolution of the apparent horizon. We also bring out several related features which throw some useful light towards understanding the

Kaj Roland, Haru-Tada Sato

We show how the multiloop bosonic Green function of closed string theory reduces to the world-line Green function as defined by Schmidt and Schubert in the limit where the string world-sheet degenerates into a $Φ^3$ particle diagram. To obtain this correspondence we have to make an appropriate choice of the local coordinates defined on the degenerate string

Eue Jin Jeong

The anomalous, energy dependent shift of the center of mass of an idealized, perfectly rigid, uniformly rotating hemispherical shell which is caused by the relativistic mass increase effect is investigated in detail. It is shown that a classical object on impact which has the harmonic binding force between the adjacent constituent particles has the similar e

Arthur Jabs

Einstein-Podolsky-Rosen correlations have so far been measured only between pairs of photons and between pairs of protons. It is proposed to measure these correlations between the proton and the neutron emerging from breakup of the deuteron induced by gamma rays near threshold. The feasibility of the experiment is discussed. Polarimeters with substantially h

A. Ohnishi, J. Randrup

We discuss a method by which quantum fluctuations can be included in microscopic transport models based on wave packets that are not energy eigenstates. By including the next-to-leading order term in the cumulant expansion of the statistical weight, which corresponds to the wave packets having Poisson energy distributions, we obtain a much improved global de

G. Martínez-Pinedo, A. Poves, L. M. Robledo, E. Caurier

The collective yrast band and the high spin states of the nucleus 50Cr are studied using the spherical shell model and the HFB method. The two descriptions lead to nearly the same values for the relevant observables. A first backbending is predicted at I=10\hbar corresponding to a collective to non-collective transition. At I=16\hbar a second backbending occ

A. M. Green, J. A. Niskanen, S. Wycech

Eta-deuteron scattering lengths are calculated. A summation of the multiple scattering series is carried out and the result is checked against more involved calculations. The necessity to go beyond the fixed nucleon approximation is emphasized. It is shown that a quasibound or virtual state in the $η$-deuteron system may occur within the range of $η$-nucleon

Naoki Tajima, Satoshi Takahara, Naoki Onishi

We have performed deformed Hartree-Fock+BCS calculations with the Skyrme SIII force for the ground states of even-even nuclei with 2 <= Z <= 114 and N ranging from outside the proton drip line to beyond the experimental frontier in the neutron-rich side. We obtained spatially localized solutions for 1029 nuclei, together with the second minima for 758 nuclei

K. L. Haglin

Vector mesons containing light quarks are thought to have their masses reduced in dense nuclear matter, sacrificing some of their energy to the scalar field which becomes appreciable at finite baryon density. Model calculations find masses which fall by a couple tens of percents in normal nuclear matter, and by several hundred MeV in dense matter. We estimat

Kevin L. Haglin

The low-mass dielectron signal from heavy-ion collisions at the CERN--SPS reported by the {\em CERES} collaboration is in excess of estimated hadronic decays suggestive of possible contribution from two-pion annihilation or other hadronic reactions. In the absence of dramatic medium modifications, annihilation alone is unable to account for the data. We expl

R. W. Nunes, J. Bennetto, David Vanderbilt

Kink defects in the 90-degree partial dislocation in silicon are studied using a linear-scaling density-matrix technique. The asymmetric core reconstruction plays a crucial role, generating at least four distinct kink species as well as soliton defects. The energies and migration barriers of these entities are calculated and compared with experiment. As a re

Frank Oertel

Given an arbitrary $p$-Banach ideal $(0 < p \leq 1)$, we ask for geometrical properties of this ideal which are sufficient (and necessary) to allow a transfer of the principle of local reflexivity to this operator class.

Frank Oertel

Given two quasi-Banach ideals \oid{A}{}{} and \oid{B}{}{} we investigate the regular hull of their composition - $(\oid{A}{}{} \circ \oid{B}{}{})^{reg}$. In concrete situations this regular hull appears more often than the composition itself. As a first example we obtain a description for the regular hull of the nuclear operators which is a &#34;reflected&#3

Frank Oertel

In addition to Pisier&#39;s counterexample of a non-accessible maximal Banach ideal, we will give a large class of maximal Banach ideals which {\it{are accessible}}. The first step is implied by the observation that a &#34;good behaviour&#34; of trace duality, which is canonically induced by conjugate operator ideals can be extended to adjoint Banach ideals,

R. Jin, Saharon Shelah

In this paper we show that the compactness of a Loeb space depends on its cardinality, the nonstandard universe it belongs to and the underlying model of set theory we live in. In section 1 we prove that Loeb spaces are compact under various assumptions, and in section 2 we prove that Loeb spaces are not compact under various other assumptions. The results i

R. Jin

Type two cuts, bad cuts and very bad cuts are introduced by Keisler and Leth for studying the relationship between Loeb measure and U-topology of a hyperfinite time line in an $ω_1$-saturated nonstandard universe. The questions concerning the existence of those cuts are asked there. In this paper we answer, fully or partially, some of those questions by show

Arnold W. Miller

This is an update of my problem list.

Xianghong Gong

We shall prove that there are totally real and real analytic embeddings of $S^k$ in $\cc^n$ which are not biholomorphically equivalent if $k\geq 5$ and $n=k+2[\frac{k-1}{4}]$. We also show that a smooth manifold $M$ admits a totally real immersion in $\cc^n$ with a trivial complex normal bundle if and only if the complexified tangent bundle of $M$ is trivial

Vincenzo Marotta, Antonino Sciarrino

The correlation function of the product of N generalized vertex operators satisfies an infinite set of Ward identities, related to a W_{\infty} algebra, whose extention out of the mass shell gives rise to equations which can be considered as a generalization of the compactified Calogero-Sutherland (CS) hamiltonians. In particular the wave function of the gro

O. Coceal, W. A. Sabra, S. Thomas

We consider possible conformal field theory (CFT) descriptions of the various inertial ranges that exist in $2d$ duality invariant Magnetohydrodynamics. Such models arise as effective theories of dyonic plasmas in 3 dimensions in which all fields are independent of the third coordinate. We find new constraints on the allowed CFT&#39;s compared to those that

R. W. Gebert, K. Koepsell, H. Nicolai

We construct an explicit representation of the Sugawara generators for arbitrary level in terms of the homogeneous Heisenberg subalgebra, which generalizes the well-known expression at level 1. This is achieved by employing a physical vertex operator realization of the affine algebra at arbitrary level, in contrast to the Frenkel--Kac--Segal construction whi

Esko Keski-Vakkuri, Per Kraus

A standard approach to analyzing tunneling processes in various physical contexts is to use instanton or imaginary time path techniques. For systems in which the tunneling takes place in a time dependent setting, the standard methods are often applicable only in special cases, e.g. due to some additional symmetries. We consider a collection of time dependent

Kayoko Maeda, Makoto Sakamoto

We propose a renormalization prescription for the Wheeler-DeWitt equation of (3+1)-dimensional Einstein gravity and also propose a strong coupling expansion as an approximation scheme to probe quantum geometry at length scales much smaller than the Planck length. We solve the Wheeler-DeWitt equation to the second order in the expansion in a class of local so

Darius G. Gagne

For any worldline reformulation of a quantum field theory for Dirac fermions, this paper shows that worldline supersymmetry may generally be enforced by the vanishing of the commutator of the Dirac operator with the worldline Hamiltonian. The action of supersymmetry on the worldline Lagrangian may not, however, be written in terms of the variations on the fi

P. Aurenche, F. Gelis, R. Kobes, E. Petitgirard

Recent studies of the high temperature soft photon production rate on the light--cone using Braaten--Pisarski resummation techniques have found collinear divergences present. We show that there exist a class of terms outside the Braaten--Pisarski framework which, although also divergent, dominate over these previously considered terms. The divergences in the

Mauro Anselmino, M. Elena Boglione, Francesco Murgia

The general formalism to describe single spin asymmetries in hadron-hadron high energy and large $p_T$ inclusive production within the QCD-improved parton model and assuming the factorization theorem to hold for higher twist contributions is discussed. Non zero values of the single spin asymmetries originate from and reveal non perturbative universal propert

Xiang-Qian Luo, Qi-Zhou Chen

We obtain accurate result for the lightest glueball mass of QCD in 3 dimensions from lattice Hamiltonian field theory. Using the dimensional reduction argument, a good approximation for confining theories, we suggest that the $0^{++}$ glueball mass in 3+1 dimensional QCD be about $1.71$ GeV.

Xiao-Gang He, Bruce McKellar

It has been shown that CP violating electron-nucleon and nucleon-nucleon interactions can induce atomic electric dipole moments and are therefore constrained from experimental data. We show that using the experimental upper bounds on neutron and electron electric dipole moments, one can also obtain constraints, in some cases better ones, on these interaction

A. Pordt, T. Reisz

We generalize the technique of linked cluster expansions on hypercubic lattices to actions that couple fields at lattice sites which are not nearest neighbours. We show that in this case the graphical expansion can be arranged in such a way that the classes of graphs to be considered are identical to those of the pure nearest neighbour interaction. The only

O. Borisenko, M. Faber, G. Zinovjev

We study the phase structure of full QCD within the canonical ensemble with respect to triality in a lattice formulation. The procedure for the calculation of the effective potentials in this case is given. As an example we consider the three dimensional SU(2) gauge model at finite temperatures in the strong coupling region. The potential exhibits a deconfin

E. M. Aitala

From a sample of $2722 \pm 78$ $Λ_c^+$ decaying to the $pK^-π^+$ final state, we have observed, in the hadroproduction experiment E791 at Fermilab, $143 \pm 20$ $Σ_c^0$ and $122 \pm 18$ $Σ_c^{++}$ through their decays to $Λ_c^+ π^{\pm}$. The mass difference $M(Σ_c^0) - M(Λ_c^+$) is measured to be $(167.38\pm 0.29\pm 0.15) {MeV}$; for $M(Σ_c^{++}) - M(Λ_c^+)$

V. A. Korotky, Yu. N. Obukhov

We overview our recent studies of cosmological models with expansion and global rotation. Problems of the early rotating models are discussed, and the class of new viable cosmologies is described in detail. Particular attention is paid to the observational effects of the cosmic rotation.

Carl H. Brans

Recent discoveries in differential topology are reviewed in light of their possible implications for spacetime models and related subjects in theoretical physics. Although not often noted, a particular smoothness (differentiability) structure must be imposed on a topological manifold before geometric or other structures of physical interest can be discussed.

Yuval Ne&#39;eman, Friedrich W. Hehl

Examples in which spacetime might become non-Riemannian appear above Planck energies in string theory or, in the very early universe, in the inflationary model. The simplest such geometry is metric-affine geometry, in which {\it nonmetricity} appears as a field strength, side by side with curvature and torsion. In matter, the shear and dilation currents coup

P. V. Moniz

The purpose of this paper is to investigate a specific FRW model derived from the theory of N=1 supergravity with gauged supermatter. The supermatter content is restricted to a vector supermultiplet. This objective is particularly worthwhile. In fact, it was pointed in ref. ({\em Class. Quantum Grav. {\bf 12} {\rm (} {\rm 1995} {\rm )} {\rm 1343}}) that $Ψ=

Clare C. Yu

We have studied a Kondo hole in a one-dimensional Kondo insulator at half-filling using a density matrix formulation of the numerical renormalization group. The Kondo hole introduces midgap states. The spin density introduced by the hole is localized in the vicinity of the hole. It resides primarily in the f-spins for small exchange coupling $J$ and in the c

J. M. P. Carmelo, A. H. Castro Neto

We generalize the concept of quasiparticle for one-dimensional (1D) interacting electronic systems. The $\uparrow $ and $\downarrow $ quasiparticles recombine the pseudoparticle colors $c$ and $s$ (charge and spin at zero magnetic field) and are constituted by one many-pseudoparticle {\it topological momenton} and one or two pseudoparticles. These excitation

J. M. P. Carmelo, N. M. R. Peres

We consider the Hubbard chain in a magnetic field and chemical potential. We introduce a pseudohole basis where all states are generated from a single reference vacuum. This allows the evaluation for all sectors of Hamiltonian symmetry of the model of the expression of the $σ$ electron and hole operators at Fermi momentum $\pm k_{Fσ}$ and vanishing excitatio

I. V. Kukushkin, Vladimir I. Fal&#39;ko, R. J. Haug, K. v. Klitzing

We compare the results of the transport and time-resolved magneto-luminescence measurements in disordered 2D electron systems in GaAs-AlGaAs heterostructures in the extreme quantum limit, in particular, in the vicinity of the metal-insulator transition (MIT). At filling factors $ν<1$, the optical signal has two components: the single-rate exponentially decay

J. P. Rodriguez

The entropic corrections to the flux-line energy of extreme type-II superconductors are computed using a schematic dual Villain model description of the flux quanta. We find that the temperature profile of the lower-critical field vanishes polynomially at the transition with an exponent $ν\cong 2/3$ in the isotropic case, while it exhibits an inflection poin