June 2000 arXiv papers — page 21

Willem T. H. van Oers

Several new proton-proton parity violation experiments are presently either being performed or are being prepared for execution in the near future. Similarly, a new measurement of the parity-violating gamma-ray asymmetry in polarized neutron capture on the proton is being developed with a ten-fold improvement over previous measurements. These experiments are

M. Ciuchini, G. Martinelli

We review the theory of epsilon'/epsilon and present an updated phenomenological analysis using hadronic matrix elements from lattice QCD. The present status of the computation of epsilon'/epsilon, considering various approaches to the matrix-element evaluation, is critically discussed.

S. Fajfer, S. Prelovsek, P. Singer, D. Wyler

We propose to investigate flavour changing neutral currents in the $c \to u γ$ transition through the measurement of the difference between $Γ(D^0 \to ρ^0 γ)$ and $Γ(D^0 \to ωγ)$. This is based on the observation that $D^0 \to (d \bar d) γ$ is due to long distance physics while $D^0 \to (u \bar u) γ$ arises from the $c \to u γ$ transition. The effect of $ρ-

S. Moch, J. A. M. Vermaseren

We summarize the method of calculating Mellin moments of deep-inelastic structure functions in perturbative QCD. We briefly discuss all steps to a complete analytical reconstruction of the perturbative corrrections in x-space.

Takahiro Tanaka

The asymptotic behavior of metric perturbations in Randall-Sundrum infinite brane world is carefully investigated. Perturbations generated by matter fields on the brane are shown to be regular even at the future Cauchy horizon.

P. Chen, N. Christ, G. Fleming, A. Kaehler

The domain wall formulation of lattice fermions is expected to support accurate chiral symmetry, even at finite lattice spacing. Here we attempt to use this new fermion formulation to simulate two-flavor, finite temperature QCD near the chiral phase transition. In this initial study, a variety of quark masses, domain wall heights and domain wall separations

T. Fujiwara, T. Hayashi, H. Suzuki, K. Wu

Block-spin transformations from a fine lattice to a coarse one are shown to give rise to a one-to-one correspondence between the zero-modes of the Ginsparg-Wilson Dirac operators. The index is then preserved under the blocking process. Such a one-to-one correspondence is violated and the block-spin transformation becomes necessarily ill-defined when the abso

P. Cea, L. Cosmai

We investigate the Abelian monopole condensation in finite temperature SU(2) and SU(3) pure lattice gauge theories. To this end we introduce a gauge invariant disorder parameter built up in terms of the lattice Schrödinger functional. Our numerical results show that the disorder parameter is different from zero and Abelian monopole condense in the confined p

The WA102 Collaboration, D. Barberis

A search for centrally produced charmonium states has been presented. There is no significant evidence for any charmonium production. An upper limit of 2 nb is found for the cross section of chic production using the decay chic(1P)-> J/psi gamma.

G. Z. Adunas, E. Rodriguez-Milla, D. V. Ahluwalia

The joint realm of quantum mechanics and the general-relativistic description of gravitation is becoming increasingly accessible to terrestrial experiments and observations. In this essay we study the emerging indications of the violation of equivalence principle (VEP). While the solar neutrino anomaly may find its natural explanation in a VEP, the statistic

E. N. Glass, J. P. Krisch

Recently, Glass and Krisch have extended the Vaidya radiating metric to include both a radiation fluid and a string fluid [1999 Class. Quantum Grav. vol 16, 1175]. Mass diffusion in the extended Schwarzschild atmosphere was studied. The continuous solutions of classical diffusive transport are believed to describe the envelope of underlying fractal behavior.

T. Padmanabhan, T. Roy Choudhury

Starting from an (unknown) quantum gravitational model, one can invoke a sequence of approximations to progressively arrive at quantum field theory (QFT) in curved spacetime, QFT in flat spacetime, nonrelativistic quantum mechanics and newtonian mechanics. The more exact theory can put restrictions on the range of possibilities allowed for the approximate th

R. J. Radwanski, Z. Ropka

On basis of analysis of experimental results for more than 200 compounds with 3d and 4f elements we conjecture that atoms with unfilled 3d and 4f shells preserve much of their atomic properties, manifested by the discrete electronic structure, even then when they become the part of a solid. As a consequence, electronic and magnetic properties of the 3d-ion c

Dimitry M. Gangardt, Shmuel Fishman

We study the localization in the Hilbert space of a modified Tomonaga-Luttinger model. For the standard version of this model, the states are found to be extended in the basis of Slater determinants, representing the eigenstates of the non-interacting system. The linear dispersion which leads to the fact that these eigenstates are extended in the modified mo

A. Mourachkine

Tunneling and inelastic neutron scattering (INS) measurements in cuprates are discussed. There is a clear discrepancy among energy-gap values for different 90 K cuprates, inferred from tunneling measurements. By using the phase diagram of hole-doped cuprates we interpret tunneling measurements in 90 K cuprates and INS data in YBCO.

D. H. E. Gross

Traditionally, phase transitions are defined in the thermodynamic limit only. We propose a new formulation of equilibrium thermo-dynamics that is based entirely on mechanics and reflects just the {\em geometry and topology} of the N-body phase-space as function of the conserved quantities, energy, particle number and others. This allows to define thermo-stat

P. Bourges, Y. Sidis, H. F. Fong, L. P. Regnault

A comprehensive inelastic neutron scattering study of magnetic excitations in the near-optimally doped high-temperature superconductor ${\rm YBa_{2}Cu_{3}O_{6.85}}$ is presented. The spin correlations in the normal state are commensurate with the crystal lattice, and the intensity is peaked around the wave vector characterizing the antiferromagnetic state of

Feng Yuan, Shiping Feng

The anomalous momentum and doping dependence of the electron spectral function and electron dispersion for copper oxide materials in the underdoped regime are studied within the t-J model. It is shown that the electron spectrum is changed with dopings, and the electron dispersion exhibits a flat band around ($π$,0) point in the Brillouin zone, which leads to

C. Villagonzalo, R. A. Römer, M. Schreiber, A. MacKinnon

We study the thermal transport properties in three-dimensional disordered systems close to the metal-insulator transition within linear response. Using a suitable form for the energy-dependent conductivity $σ$, we show that the value of the dynamical scaling exponent for noninteracting disordered systems such as the Anderson model of localization can be repr

T. Bickel, C. Jeppesen, C. M. Marques

In this paper, we study the equilibrium properties of polymer chains end-tethered to a fluid membrane. The loss of conformational entropy of the polymer results in an inhomogeneous pressure field that we calculate for gaussian chains. We estimate the effects of excluded volume through a relation between pressure and concentration. Under the polymer pressure,

Xianglin Le, Feng Yuan, Shiping Feng

The effect of the additional second neighbor hopping t' on the spin dynamics in the t-J model is studied within the fermion-spin theory. Although the additional second neighbor hopping t' is systematically accompanied with the reduction of the dynamical spin structure factor and susceptibility, the qualitative behaviors of the dynamical spin structur

Avinash Singh

The spectral function of transverse spin fluctuations, including the contributions from both the single-particle and the collective (magnon) excitations in an antiferromagnet, is evaluated for the Hubbard model with NN and NNN hoppings in the full U-range from weak coupling to strong coupling. For the NN hopping model, the magnon excitations are dominant for

L. L. Kiss, K. Szatmary, Gy. Szabo, J. A. Mattei

We present a detailed lightcurve analysis for a sample of bright semiregular variables based on long-term (70--90 years) visual magnitude estimates carried out by amateur astronomers. Fundamental changes of the physical state (amplitude and/or frequency modulations, mode change and switching) are studied with the conventional Fourier- and wavelet analysis. T

Gordon Garmire, Eric D. Feigelson, Patrick Broos, Lynne A. Hillenbrand

About 1000 X-ray emitting young pre-main sequence (PMS) stars distributed in mass from 0.05 to 50 solar masses are detected in an image of the Orion Nebula obtained with the Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory. This is the richest field of sources ever obtained in X-ray astronomy. ACIS sources include 85-90% of V<20 stars

E. Mason, W. Skidmore, S. B. Howell, D. R. Ciardi

We present our second paper describing multi-wave-band, time-resolved spectroscopy of WZ Sge. We analyze the evolution of both optical and IR emission lines throughout the orbital period and find evidence, in the Balmer lines, for an optically thin accretion disk and an optically thick hot-spot. Optical and IR emission lines are used to compute radial veloci

Antonis Georgakakis, Duncan A. Forbes, Ray P. Norris

We explore the evolution of the cold gas and star-formation activity during galaxy interactions, using a merging galaxy sequence comprising both pre- and post-mergers. Data for this study come from the literature but supplemented by new radio observations presented here. Firstly, we confirm that the star-formation efficiency (SFE) increases close to nuclear

Nazeem Mustapha, Charles Hellaby

We consider a spherically symmetric distribution of dust and show that it is possible, under general physically reasonable conditions, for an overdensity to evolve to an underdensity (and vice versa). We find the conditions under which this occurs and illustrate it on a class of regular Lemaitre-Tolman-Bondi solutions. The existence of this phenomenon, if ve

Matt J. Jarvis, Steve Rawlings

We use data from the Parkes Half-Jansky Flat-Spectrum (PHJFS) sample (Drinkwater et al. 1997) to constrain the cosmic evolution in the co-moving space density of radio sources in the top decade of the flat-spectrum radio luminosity function (RLF). A consistent picture for the high-redshift evolution is achieved using both simple parametric models, which are

A. Fassia, W. P. S. Meikle, W. D. Vacca, S. N. Kemp

We present contemporaneous optical and infrared photometric observations of the type IIn SN 1998S covering the period between 11 and 146 days after discovery. The infrared data constitute the first ever infrared light curves of a type IIn supernova. We use blackbody and spline fits to the photometry to examine the luminosity evolution. During the first 2--3

Toshitaka Kajino, Kaori Otsuki, Shin-ya Wanajo, Manabu Orito

We study the few body reactions in explosive nucleosynthesis of light-to-heavy mass elements in various astrophysical conditions. In neutrino-driven winds of gravitational core collapse of SNeII, several light nuclei as well as heavy unstable nuclei paly significant roles in producing r-process elements. We discuss how the three-body reaction $^4$He$(αn, γ)^

J. M. Diego, E. Martinez-Gonzalez, J. L. Sanz, L. Cayon

In this work we show that combining different cluster data sets is a powerful tool to constrain both, the cosmology and cluster properties. We assume a model with 9 parameters and fit them to 5 cluster data sets. From that fit, we conclude that only low density universes are compatible with the previous data and we also get some interesting conclusions on th

Alberto Carraminana, Andrej Cadez, Tomaz Zwitter

A dedicated stroboscopic device was used to obtain optical spectra of the Crab main-pulse and inter-pulse as well as the spectrum of the underlying nebula when the pulsar is turned off. As the nebular emission is very inhomogeneous, our ability to effectively subtract the nebular background signal is crucial. No spectral lines intrinsic to the pulsar are det

F. Zagury

In 1986 Witt & Schild studied the optical emission of selected bright nebulae. Comparison of the data to a model led the authors to conclude the nebulae have too high a level of I-band emission to be explained solely by the scattering of starlight. The excess is explained as a broad band I emission which originates in the nebulae. This phenomenum is known as

Leo C. Brewin, Adrian P. Gentle

Motivated by a recent study casting doubt on the correspondence between Regge calculus and general relativity in the continuum limit, we explore a mechanism by which the simplicial solutions can converge whilst the residual of the Regge equations evaluated on the continuum solutions does not. By directly constructing simplicial solutions for the Kasner cosmo

Frank C. van den Bosch, Rob A. Swaters

The standard cold dark matter (CDM) model has recently been challenged by the claim that dwarf galaxies have dark matter halos with constant density cores. Consequently, numerous alternative dark matter candidates have recently been proposed. In this paper, we scrutinize the observational evidence for the incongruity between dwarf galaxies and the CDM model.

Michael N. Leuenberger, Daniel Loss

We present topological interference effects for the tunneling of a single large spin, which are caused by the symmetry of a general class of magnetic anisotropies. The interference originates from spin Berry phases associated with different tunneling paths exposed to the same dynamics. Introducing a generalized path integral for coherent spin states, we eval

L. Baulieu, P. A. Grassi, D. Zwanziger

A gauge theory with 4 physical dimensions can be consistently expressed as a renormalizable topological quantum field theory in 5 dimensions. We extend the symmetries in the 5-dimensional framework to include not only a topological BRST operator S that encodes the invisibility of the &#34;bulk&#34; (the fifth dimension), but also a gauge BRST operator W that

Y. G. Yi

An optical approach begins by interpreting the gravitational redshift resulting to a change in the relative velocity of light due to the medium of propagation in the gravitational field. The discussion continues by pointing out an agreement in structure between the equation for rays in geometrical optics and the geodesic equation of general relativity. From

Utpal Chattopadhyay, Dilip Kumar Ghosh, Sourov Roy

The ongoing high precision E821 Brookhaven National Laboratory experiment on muon g-2 is promising to probe a theory involving supersymmetry. We have studied the constraints on the minimal Anomaly Mediated Supersymmetry Breaking (AMSB) model using the current data of muon g-2 from Brookhaven. A scenario of seeing no deviation from the Standard Model is also

P. K. Panda, T. Csorgo, Y. Hama, G. Krein

Large back-to-back correlations of observable fermion -- anti-fermion pairs are predicted to appear, if the mass of the fermions is modified in a thermalized medium. The back-to-back correlations of protons and anti-protons are experimentally observable in ultra-relativistic heavy ion collisions, similarly to the Andreev reflection of electrons off the bound

Y. G. Yi

A phenomenological explanation is presented for the physics of aberration, which is in contrast with special relativity physics. The effect of relativity is identified with an effect due to the velocity of observation being affected by the velocity of a moving particle. In contrast with the currently accepted view, it is demonstrated that the classical conce

K. H. Michel, A. V. Nikolaev

The polymer phases of AC60 form distinct crystal structures characterized by the mutual orientations of the (C60-)n chains. We show that the direct electric quadrupole interaction between chains always favors the orthorhombic structure Pmnn with alternating chain orientations. However the specific quadrupolar polarizability of the alkali metal ions leads to

Ernest Ma, Martti Raidal, Utpal Sarkar

We propose a new scenario of neutrino masses with a Higgs triplet $(ξ^{++},ξ^+,ξ^0)$ in a theory of large extra dimensions. Lepton number violation in a distant brane acts as the source of a very small trilinear coupling of $ξ$ to the standard Higgs doublet in our brane. Small realistic Majorana neutrino masses are \underline{naturally} obtained with the fun

Jan-Åke Larsson, Jason Semitecolos

An analysis of detector-efficiency in many-site Clauser-Horne inequalities is presented, for the case of perfect visibility. It is shown that there is a violation of the presented n-site Clauser-Horne inequalities if and only if the efficiency is greater than n/(2n-1). Thus, for a two-site two-setting experiment there are no quantum-mechanical predictions th

A. Fabbri, D. J. Navarro, J. Navarro-Salas

We study the near-horizon AdS_2\timesS^2 geometry of evaporating near-extremal Reissner-Nordstrom black holes interacting with null matter. The non-local (boundary) terms t_{\pm}, coming from the effective theory corrected with the quantum Polyakov-Liouville action, are treated as dynamical variables. We describe analytically the evaporation process which tu

Carlo Angelantonj, Ralph Blumenhagen, Matthias R. Gaberdiel

A new class of six-dimensional asymmetric orientifolds is considered where the orientifold operation is combined with T-duality. The models are supersymmetric in the bulk, but the cancellation of the tadpoles requires the introduction of brane configurations that break supersymmetry. These can be described by D7-brane anti-brane pairs, non-BPS D8-branes or D

A. A. Deriglazov

We study string action with multiplet of $Θ$-terms added, which turns out to be closely related with the bosonic sector of D=11 superstring action [3,4]. Alternatively, the model can be considered as describing class of special solutions of the membrane. An appropriate set of variables is find, in which the light-cone quantization turns out to be possible. I

D. Ward-Thompson, J. M. Kirk, R. M. Crutcher, J. S. Greaves

We present the first published maps of magnetic fields in pre-stellar cores, to test theoretical ideas about the way in which the magnetic field geometry affects the star formation process. The observations are JCMT-SCUBA maps of 850 micron thermal emission from dust. Linear polarizations at typically ten or more independent positions in each of three object

Ian I. Kogan, Stavros Mouslopoulos, Antonios Papazoglou, Graham G. Ross

We discuss the implications of multi-brane constructions involving combinations of positive and negative tension brane and show how anomalously light KK states emerge when negative tension &#39;&#39;-&#39;&#39; branes are sandwiched between &#39;&#39;+&#39;&#39; branes. We present a detailed study of a &#39;&#39;+--+&#39;&#39; brane assignment which interpol

M. Maul, D. Diakonov

In the two-dimensional CP(N-1) model one can parametrize exact many-instanton solutions via N `constituents&#39; (called `zindons&#39;). This parameterization allows, in principle, a complete `melting&#39; of individual instantons. The model is therefore well suited to study whether dynamics prefers a dilute or a strongly overlapping ensemble of instantons.

Tom Theuns, H. J. Mo, Joop Schaye

Models for the formation of galaxies and clusters of galaxies require strong feedback in order to explain the observed properties of these systems. We investigate whether such feedback has observational consequences for the intergalactic medium, as probed in absorption towards background quasars. A typical quasar sight-line intersects one proto-cluster per u

Johan Bijnens, Martin Maul

The prospect of experimental verification of the large extra dimension scenario in rare decays is discussed. The case of J/Ψand Υto photon + missing energy is calculated in detail, and it is shown that the limit on the compactification scale M_S lies at present in the ten GeV range. In contrast to the quarkonium systems, signals in Kaon and Pion decays will

V. Dzhunushaliev

An approximate model of the spacetime foam is offered in which a quantum handle (wormhole) is a 5D wormhole-like solution. Neglecting the linear sizes of the wormhole throat we can introduce a spinor field for an approximate and effective description of the foam. The definition of the spinor field can be made by a dynamic and non-dynamic ways. In the first c

Krishna Bhuvalka, Pankaj Jain

We study the polarization of light emitted by spatially correlated sources. We show that in general polarization acquires nontrivial spectral dependence due to spatial correlations. The spectral dependence is found to be absent only for a special class of sources where the correlation length scales as the wavelength of light. We further study the cross corre

Masa-Hiko Saito, Taro Takebe, Hitomi Terajima

In this paper, we introduce the notion of generalized rational Okamoto-Painlevé pair (S, Y) by generalizing the notion of the spaces of initial conditions of Painlevé equations. After classifying those pairs, we will establish an algebro-geometric approach to derive the Painlevé differential equations from the deformation of Okamoto-Painlevé pairs by using t

H. D. Zeh

Epistemological consequences of quantum nonlocality (entanglement) are discussed under the assumption of a universally valid Schrödinger equation in the absence of hidden variables. This leads inevitably to a {\it many-minds interpretation}. The recent foundation of quasi-classical neural states in the brain (based on environmental decoherence) permits in pr

Jaromir Fiurasek

We derive various sampling functions for multimode homodyne tomography with a single local oscillator. These functions allow us to sample multimode s-parametrized quasidistributions, density matrix elements in Fock basis, and s-ordered moments of arbitrary order directly from the measured quadrature statistics. The inevitable experimental losses can be compe

J H Samson

We consider a set of operators hat{x}=(hat{x}_1,..., hat{x}_N) with diagonal representatives P(n) in the space of generalized coherent states |n>; hat{x}=int dn P(n) |n><n|. We regularize the coherent-state path integral as a limit of a sequence of averages <.>_L over polygonal paths with L vertices {n_1...L}. The distribution of the path centroid bar{P}=(1/

Michael Stone

I consider the time evolution of generalized coherent states based on non-standard fiducial vectors, and show that only for a restricted class of fiducial vectors does the associated classical motion determine the quantum evolution of the states. I discuss some consequences of this for path integral representations.

Toshiki Shimbori, Tsunehiro Kobayashi

In the two-dimensional isotropic parabolic potential barrier $V(x, y)=V_0 -mγ^2 (x^2+y^2)/2$, though it is a model of an unstable system in quantum mechanics, we can obtain the stationary states corresponding to the real energy eigenvalue $V_0$. Further, they are infinitely degenerate. For the first few eigenstates, we will find the stationary flows round a

Robert Alicki

A theoretical model of a quantum device which can factorize any number N in two steps i.e. by preparing an input state and performing a measurement is discussed. The analysis reveals that the duration of state preparation and measurement is proportional to N while the energy consumption grows like log N. These results suggest the existence of Heisenberg-type

Georg H. Hoffstaetter

Single particle dynamics in electron microscopes, ion or electron lithographic instruments, particle accelerators, and particle spectrographs is described by weakly nonlinear ordinary differential equations. Therefore, the linear part of the equation of motion is usually solved and the nonlinear effects are then found in successive order by iteration methods

Georg H. Hoffstaetter

Polarized proton beams at HERA can currently only be produced by extracting a beam from a polarized source and then accelerating it in the three synchrotrons at DESY. In this paper, the processes which can depolarize a proton beam in circular accelerators are explained, devices which could avoid this depolarization in the DESY accelerator chain are described

N. A. Zabotin, Yu. V. Chugunov, E. A. Mareev, A. G. Bronin

The influence of random irregularities of electron density on quasi-thermal noise spectra in plasma is considered in the paper. Quasi-thermal noise spectrum of plasma in state near the thermal equilibrium is determined by effective dielectric constant tensor. Presence of random irregularities change dispersion law in plasma what cause the change in the shape

L. E. Marcucci, R. Schiavilla, M. Viviani, A. Kievsky

The astrophysical S-factor for the proton weak capture on 3He is calculated with correlated-hyperspherical-harmonics bound and continuum wave functions corresponding to realistic Hamiltonians consisting of the Argonne v14 or Argonne v18 two-nucleon and Urbana-VIII or Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vec

Tamanna Rumin, Kouichi Hagino, Noboru Takigawa

In heavy-ion fusion reactions involving a well deformed nucleus, one often assumes that the orientation of the target nucleus does not change during the reaction. We discuss the accuracy of this procedure by analyzing the excitation function of the fusion cross section and the fusion barrier distribution in the reactions of $^{154}$Sm target with various pro

V. M. Castillo, Wm. G. Hoover

Computer simulations of a compressible fluid, convecting heat in two dimensions, suggest that, within a range of Rayleigh numbers, two distinctly different, but stable, time-dependent flow morphologies are possible. The simpler of the flows has two characteristic frequencies: the rotation frequency of the convecting rolls, and the vertical oscillation freque

Sergey Gavrilets

Using a weak migration and weak mutation approximation, I study the average waiting time to and the average duration of parapatric speciation. The description of reproductive isolation used is based on the classical Dobzhansky model and its recently proposed multilocus generalizations. The dynamics of parapatric speciation is modeled as a biased random walk

Denis Perrot

We consider the mixed gravitational-Yang-Mills anomaly as the coupling between the $K$-theory and $K$-homology of a $C^*$-algebra crossed product. The index theorem of Connes-Moscovici allows to compute the Chern character of the $K$-cycle by local formulae involving connections and curvatures. It gives a topological interpretation to the anomaly, in the sen

Robert Seiringer

We give upper bounds for the number of spin 1/2 particles that can be bound to a nucleus of charge Z in the presence of a magnetic field B, including the spin-field coupling. We use Lieb&#39;s strategy, which is known to yield N_c<2Z+1 for magnetic fields that go to zero at infinity, ignoring the spin-field interaction. For particles with fermionic statistic

Klaus-Detlef Kuersten, Elmar Wagner

A generalization of the GNS-representation is investigated that represents partial ^*-algebras as systems of operators acting on a partial inner product space (PIP-space). It is based on possibly indefinite B-weights which are closely related to the positive B-weights introduced by J.-P. Antoine, Y. Soulet and C. Trapani. Some additional assumptions had to b

Xavier Tolsa

Let $μ$ be a Borel measure on $R^d$ which may be non doubling. The only condition that $μ$ must satisfy is $μ(B(x,r))\leq C r^n$ for all $x\in R^d$, $r>0$, and for some fixed $0<n\leq d$. In this paper, we develop Littlewood-Paley theory for functions in $L^p(μ)$. One of the main difficulties is the construction of reasonable approximations of the identity f

Kenji Matsuki

This is an erratum to math.AG/9803126, Tohoku 51 (1999) 489-537. This erratum describes: 1. the failure of the algorithm in [AMR] and [Morelli1] for the strong factorization pointed out by Kalle Karu, 2. the statement of a refined weak factorization theorem for toroidal birational morphisms in [AMR], in the form utilized in [AKMR] for the proof of the weak f

Levent Tuncel, Michel X. Goemans

We study the lift-and-project procedures of Lovász and Schrijver for 0-1 integer programming problems. We prove that the procedure using the positive semidefiniteness constraint is not better than the one without it, in the worst case. Various examples are considered. We also provide geometric conditions characterizing when the positive semidefiniteness cons

Steven Shin-Yi Lu, Gregery T. Buzzard

As is well-known, there exist nonconstant holomorphic maps from the plane into the Riemann sphere $\PP^1$ minus two points, the simplest example of which is an explicit realization of the uniformization map given by applying the exponential map and then composing with a Mobius transformation taking 0 and $\infty$ to the two given punctures. Likewise, we can

Andreas Defant, Mieczysław Mastyło, Carsten Michels

We prove a substantial extension of a well-known result due to Bennett and Carl: The inclusion of a 2-concave symmetric Banach sequence space E into l_2 is (E,1)-summing, i.e. for every unconditionally summable sequence (x_n) in E the scalar sequence (||x_n||_2) is contained in E. Various applications are given, e.g. to the theory of eigenvalue distribution

Jesper Mygind

We show that the Elliott invariant is a classifying invariant for the class of $C^*$-algebras that are simple unital infinite dimensional inductive limits of sequences of finite direct sums of building blocks of the form $$ \{f\in C(\T)\otimes M_n: f(x_i)\in M_{d_i}, i=1,2,...,N\}, $$ where $x_1,x_2,...,x_N\in\T$, $d_1,d_2,...,d_N$ are integers dividing $n$,

Maria Giovanna Mora, Massimiliano Morini

We deal with a family of functionals depending on curvatures and we prove for them compactness and semicontinuity properties in the class of closed and bounded sets which satisfy a uniform exterior and interior sphere condition. We apply the results to state an existence theorem for the Nitzberg and Mumford problem under this additional constraint.

Masa-Hiko Saito, Taro Takebe

In this paper, we introduce the notion of an Okamoto-Painlevé pair (S, Y) which consists of a compact smooth complex surface S and an effective divisor Y on S satisfying certain conditions. Though spaces of initial values of Painlevé equations introduced by K. Okamoto give examples of Okamoto-Painleve pairs, we find a new example of Okamoto-Painlevé pairs no

Hitomi Terajima

In the theory of deformation of Okamoto-Painlevé pair (S,Y), a local cohomology group $H^1_D(Θ_S(-\log D))$ plays an important role. In this paper, we estimate the local cohomology group of pair (S,Y) for several types, and obtain the following results. For a pair (S,Y) corresponding to the space of initial conditions of the Painlevé equations, we show that

Atsushi Moriwaki

In our previous paper, we established Northcott&#39;s theorem for height functions over finitely generated fields. Unfortunately, Northcott&#39;s theorem on finitely generated fields does not hold in general. Actually, it depends on the choice of a polarization. In this short note, we will propose a weaker condition of the polarization to guarantee Northcott

Marijan Ribaric, Luka Sustersic

Generalizing the &#39;t Hooft and Veltman method of unitary regulators, we demonstrate for the first time the existence of local, Lorentz-invariant, physically motivated Lagrangians of quantum-electrodynamic phenomena such that: (i) Feynman diagrams are finite and equal the diagrams of QED but with regularized propagators. (ii) N-point Green functions are ca

K. Koepsell, H. Nicolai, H. Samtleben

We analyze the algebraic constraints of the generalized vielbein in SO(1,2) x SO(16) invariant d=11 supergravity, and show that the bosonic degrees of freedom of d=11 supergravity, which become the physical ones upon reduction to d=3, can be assembled into an E_8-valued vielbein already in eleven dimensions. A crucial role in the construction is played by th

M. Blagojevic

This is a review of the constrained dynamical structure of Poincare gauge theory which concentrates on the basic canonical and gauge properties of the theory, including the identification of constraints, gauge symmetries and conservation laws. As an interesting example of the general approach we discuss the teleparallel formulation of general relativity.

Miao Li

In addition to briefly reviewing recent progress in studying black hole physics in string/M theory, we describe several robust features pertaining to spacetime physics that one can glean by studying quantum physics of black holes. In particular, we review &#39;t Hooft&#39;s S-matrix ansatz which results in a noncommutative horizon. A recent construction of f

Amir H. Fatollahi

The possibility of using the quantum mechanics of D0-branes for the bound-states of quarks and QCD strings is investigated. Issues such as the inter D0-branes potential, the whiteness of the D0-branes bound-states and the large-N limit of D0-branes effective theory are studied. A possible role of the non-commutativity of relative distances of D0-branes in a

P. K. Townsend

Field theories that describe {\sl small} fluctuations of branes are limits of `brane theories&#39; that describe {\sl large} fluctuations. In particular, supersymmetric sigma-models arise in this way. These lectures discuss the soliton solutions of the associated `brane theories&#39; and their relation to calibrations.

Jens Erler

I discuss supersymmetric extensions of the Standard Model containing an extra U(1)&#39; gauge symmetry which provide a solution to the mu-problem and at the same time protect the proton from decaying via dimension 4 operators. Moreover, all fields are protected by chirality and supersymmetry from acquiring high scale masses. The additional requirements of an

Howard Georgi, Aaron K. Grant

We discuss an alternative to the topcolor seesaw mechanism. In our scheme, all the light quarks carry topcolor, and there are many composite SU(2) doublets. This makes it possible to get the observed top quark mass and observed $SU(2) \times U(1)$ breaking in a way that is quite different from the classic seesaw mechanism. We discuss a model of this kind tha

Z. Chacko, M. Luty, E. Ponton, Y. Shadmi

We consider models of anomaly-mediated supersymmetry breaking (AMSB) in which the grand unification (GUT) scale is determined by the vacuum expectation value of a chiral superfield. If the anomaly-mediated contributions to the potential are balanced by gravitational-strength interactions, we find a model-independent prediction for the GUT scale of order $M_{

Matthias Jamin, Jose Antonio Oller, Antonio Pich

We present a detailed analysis of S-wave Kpi scattering up to 2 GeV, making use of the resonance chiral Lagrangian predictions together with a suitable unitarisation method. Our approach incorporates known theoretical constraints at low and high energies. The present experimental status, with partly conflicting data from different experiments, is discussed.

I. Royen

We study the helicity amplitudes describing the quasielastic production of vector mesons in deep inelastic scattering within the context of the model which we previously introduced to describe the ratio of longitudinal to transverse cross sections. We calculate here a full set of spin flip (and non-flip) amplitudes and naturally find a significant violation

A. Gómez Nicola, J. Nieves, J. R. Peláez, E. Ruiz Arriola

We show how the unitarized description of pion nucleon scattering within Heavy Baryon Chiral Perturbation Theory can be considerably improved, by a suitable reordering of the expansion over the nucleon mass. Within this framework, the $Δ$ resonance and its associated pole can be recovered from the chiral parameters obtained from low-energy determinations. In

H. Davoudiasl, J. L. Hewett, T. G. Rizzo

The phenomenology of the Randall-Sundrum model of localized gravity is analyzed in detail for the two scenarios where the Standard Model (SM) gauge and matter fields are either confined to a TeV scale 3-brane or may propagate in a slice of five dimensional anti-deSitter space. In the latter instance, we derive the interactions of the graviton, gauge, and fer

V. Börchers, J. Meyer, St. Gieseke, G. Martens

We present a new cascade-type microscopic simulation of nucleus-nucleus collisions at RHIC energies. The basic elements are partons (quarks and gluons) moving in 8N-dimensional phase space according to Poincare-covariant dynamics. The parton-parton scattering cross sections used in the model are computed within perturbative QCD in the tree-level approximatio

Hiroshi Suzuki

This paper has been withdrawn by the author.

John C. Henderson

The popularity of applying machine learning methods to computational linguistics problems has produced a large supply of trainable natural language processing systems. Most problems of interest have an array of off-the-shelf products or downloadable code implementing solutions using various techniques. Where these solutions are developed independently, it is

John C. Henderson, Eric Brill

Bagging and boosting, two effective machine learning techniques, are applied to natural language parsing. Experiments using these techniques with a trainable statistical parser are described. The best resulting system provides roughly as large of a gain in F-measure as doubling the corpus size. Error analysis of the result of the boosting technique reveals s

Andrea Asperti, Luca Roversi

This paper is a structured introduction to Light Affine Logic, and to its intuitionistic fragment. Light Affine Logic has a polynomially costing cut elimination (P-Time correctness), and encodes all P-Time Turing machines (P-Time completeness). P-Time correctness is proved by introducing the Proof nets for Intuitionistic Light Affine Logic. P-Time completene

Rajeev Gupta, Janhavi P. Joshi, S. V. Bhat, A. K. Sood

We report the first electron paramagnetic resonance studies of single crystals and powders of Pr_{0.6}Ca_{0.4}MnO_{3} in the 300-4.2 K range, covering the charge ordering transition at ~ 240 K and antiferromagnetic transition (T_N) at ~ 170 K. The asymmetry parameter for the Dysonian single crystal spectra shows anomalous increase at T_{co}. Below T_{co} the