August 1997 arXiv papers — page 14

W. -S. Hou, G. -L. Lin, C. -Y. Ma

We explore the possibility of detecting flavor changing neutral Higgs couplings at the Next Linear Collider (NLC) through $e^+e^-\to ν_e\bar{ν_e} t\bar{c}$. In the framework of a general two-Higgs doublet model, we perform a complete calculation and find that $σ(e^+e^-\to ν_eν_e t\bar{c}, ν_e\bar{ν_e} {\bar t}c)$ could reach $\sim 9$ fb for $\sqrt{s}=2 TeV$.

Kazuo Fujikawa, Kazumi Okuyama

A global supersymmetry (SUSY) in supersymmetric gauge theory is generally broken by gauge fixing. A prescription to extract physical information from such SUSY algebra broken by gauge fixing is analyzed in path integral framework. If $δ_{SUSY}δ_{BRST}Ψ= δ_{BRST}δ_{SUSY}Ψ$ for a gauge fixing ``fermion'' $Ψ$, the SUSY charge density is written as a sum

J. Hashiba, M. Kawasaki, T. Yanagida

The dilaton field in string theories (if exists) is expected to have a mass of the order of the gravitino mass $m_{3/2}$ which is in a range of $10^{-2}$keV--1GeV in gauge-mediated supersymmetry breaking models. If it is the case, the cosmic energy density of coherent dilaton oscillation easily exceeds the critical density of the present universe. We show th

Max Tegmark, Andrew Hamilton, Michael Strauss, Michael Vogeley

Precision measurements of the galaxy power spectrum P(k) require a data analysis pipeline that is both fast enough to be computationally feasible and accurate enough to take full advantage of high-quality data. We present a rigorous discussion of different methods of power spectrum estimation, with emphasis on the traditional Fourier method, the linear (Karh

A. Nagai, T. Tokihiro, J. Satsuma, R. Willox

A deautonomized version of the two-dimensional Toda lattice equation is presented. Its ultra-discrete analogue and soliton solutions are also discussed.

J. Steinbach, J. Twamley, P. L. Knight

We describe how two vibrational degrees of freedom of a single trapped ion can be coupled through the action of suitably-chosen laser excitation. We concentrate on a two-dimensional ion trap with dissimilar vibrational frequencies in the x- and y-directions of motion, and derive from first principles a variety of quantized two-mode couplings, concentrating o

Frank Hausser, Florian Nill

Let \G be a (weak) quasi-Hopf algebra. Using a two-sided \G-coaction on an algebra \M, we construct what we call the diagonal crossed product as a new associative algebra structure on \M\otimes \dG, where \dG is the dual of \G. This construction is largely motivated by the special case \M = \G, for which we obtain an explicit definition of the quantum double

Jonathan Gratus

The product of two Heisenberg-Weil algebras contains the Jordan-Schwinger representation of su(2). This Algebra is quotiented by the square-root of the Casimir to produce a non-associative algebra denoted by $Ψ$. This algebra may be viewed as the right-module over one of its associative subalgebras which corresponds to the algebra of scalar fields on the non

F. Jamitzky

A differential geometric approach to singular perturbation theory is presented. It is shown that singular perturbation problems such as multiple-scale and boundary layer problems can be treated more easily on a differential geometric basis. A general method is proposed based on differential forms and Lie-derivatives. Examples from multiple scale theory, boun

R. S. Mackintosh, S. G. Cooper

The iterative-perturbative (IP) procedure for S-matrix to potential inversion is applied to spin-one projectiles for the restricted case of vector spin-orbit interaction only. In order to evaluate this extension of IP inversion we have inverted the multi-channel RGM $S_{lj}$ of Kanada et al for deuterons scattering from $^4$He with deuteron distortion and th

The Dilepton Spectrometer, Collaboration, :, W. K. Wilson

Measurements of dielectron production in p+p and p+d collisions with beam kinetic energies from 1.04 to 4.88 GeV are presented. The differential cross section is presented as a function of invariant pair mass, transverse momentum, and rapidity. The shapes of the mass spectra and their evolution with beam energy provide information about the relative importan

Nakhlé Asmar, Stephen J. Montgomery-Smith, Sadahiro Saeki

The transference theory for Lp spaces of Calderon, Coifman, and Weiss is a powerful tool with many applications to singular integrals, ergodic theory, and spectral theory of operators. Transference methods afford a unified approach to many problems in diverse areas, which before were proved by a variety of methods. The purpose of this paper is to bring about

Stefano Liberati, Giuseppe Pollifrone

In this work a relation between topology and thermodynamical features of gravitational instantons is shown. The expression for the Euler characteristic, through the Gauss-Bonnet integral, and the one for the entropy of gravitational instantons are proposed in a form that makes the relation between them self-evident. A new formulation of the Bekenstein-Hawkin

Michael R. Douglas, Akishi Kato, Hirosi Ooguri

We consider actions for N D-branes at points in a general Kahler manifold, which satisfy the axioms of D-geometry, and could be used as starting points for defining Matrix theory in curved space. We show that the axioms cannot be satisfied unless the metric is Ricci flat, and argue that such actions do exist when the metric is Ricci flat. This may provide an

G. Curio

We review aspects of N=2 duality between the heterotic and the type IIA string. After a description of string duality intended for the non-specialist the computation of the heterotic prepotential and the $F_1$ function for the ST, STU and STUV model (V a Wilson line) and the matching with the Calabi-Yau instanton expansions are given in detail. Relations wit

Z. Bern, L. Dixon, D. A. Kosower

We present the first explicit formulae for the complete set of one-loop helicity amplitudes necessary for computing next-to-leading order corrections for e^+ e^- annihilation into four jets, for W, Z or Drell-Yan production in association with two jets at hadron colliders, and for three-jet production in deeply inelastic scattering experiments. We include a

I. G. Aznauryan

Within the dispersion relation approach, solutions of integral equations for the multipoles M_{1+}^{3/2},E_{1+}^{3/2},S_{1+}^{3/2} are found at 0 < Q^2 < 3 GeV^2. These solutions should be used as input for the resonance and nonresonance contributions in the analyses of pion electroproduction data in the P_{33}(1232) resonance region. It is shown that the tr

W. Roberts, A. Rakotovao

We present a brief discussion of the general form of the amplitude that describes the two-pion photoproduction process. We outline an effective Lagrangian method that we are using to calculate this amplitude, and comment briefly on a few aspects of the calculation.

W. Roberts, B. Silvestre-Brac

A recent model of hadron states is extended to include meson decays. We find that the overall success of the model is quite good. Possible improvements to the model are suggested.

C. A. Dominguez

Three different ways of determining the strange quark mass using QCD sum rules are reviewed. First, from a QCD sum rule determination of the up and down quark masses, together with the current algebra ratio $ m_{s}/(m_{u}+m_{d})$. Second and third, from QCD sum rules involving the strangeness changing vector and axial-vector current divergences, respectively

Giorgio Calucci, Daniele Treleani

The negative binomial distribution is self similar: If the spectrum over the whole rapidity range gives rise to a negative binomial, in absence of correlation and if the source is unique, also a partial range in rapidity gives rise to the same distribution. The property is not seen in experimental data, which are rather consistent with the presence of a numb

J. Bijnens, P. Gosdzinsky, P. Talavera

We show how to obtain a ``heavy'' meson effective lagrangian for the case where the number of heavy particles is not conserved. We apply the method in a simple example at tree level and perform then the reduction for the case of vector mesons in Chiral Perturbation Theory in a manifestly chiral invariant fashion. Some examples showing that ``heavy'' meson ef

Erwin Mirkes, Stefan Willfahrt

A Monte Carlo study of the azimuthal angular distribution around the virtual boson-proton beam axis for dijet events in DIS at HERA is presented. In the presence of typical acceptance cuts on the jets in the laboratory frame, the azimuthal distribution is dominated by kinematic effects rather than the typical $\cosϕ$ and $\cos 2ϕ$ dependence predicted by the

S. V. Molodtsov

The problem of two nonrelativistic chromoelectric and chromomagnetic charges in a Higgs vacuum is considered in classical field theory. An approximation of interaction potential is constructed on the basis of a numerical solution to the equations of gluostatics. The concept of a non-Abelian Abrikosov vortex is discussed. It is shown that the results of Ginzb

Antal Jakovac

It is shown that in a scalar quantum field theory at high temperatures we can compute even time dependent observables from an effective theory, which can be interpreted as a (nonlocal) classical statistical field theory. We examine the retarded Greens function in the local approximation, and define the classical self energy. Its imaginary part agrees with th

Jisuke Kubo, Myriam Mondragon, George Zoupanos

Unification of Gauge and Yukawa sectors of GUTs is obtained by searching for renormalization group invariant relations among the couplings of the both sectors which hold beyond the unification scale. This procedure singled out two supersymmetric GUTs, the finite and the minimal SU(5) models which, among others, were predicting successfully the top quark mass

D. J. Miller

A partisan review of some of the most important $γγ$ channels accessible at LEP 2, with special stress on the measurement of the photon structure function $F_{2}^γ$ and on associated problems with Monte Carlo modelling.

Inyong Cho, Alexander Vilenkin

The evolution of a global monopole with an inflating core is investigated. An analytic expression for the exterior metric at large distances from the core is obtained. The overall spacetime structure is studied numerically, both in vacuum and in a radiation background.

C. W. M. Castleton, M. W. Long

The need for suitable many or infinite fermion correlation functions to describe some low dimensional strongly correlated systems is discussed. This is linked to the need for a correlated basis, in which the ground state may be postive definite, and in which single particle correlations may suffice. A particular trial basis is proposed, and applied to a cert

A. Damascelli, D. van der Marel, F. Parmigiani, G. Dhalenne

We investigated the infrared reflectivity of several Mg- and Si-substituted CuGeO3 single crystals. The temperature dependent b-axis and c-axis optical response is reported. For T<Tsp we detected the activation of zone-boundary phonons along the b axis of the crystal on the pure sample and for 1% Mg and 0.7% Si concentrations. From a detailed analysis of the

M. E. Foglio, M. S. Figueira

The diagrammatic cumulant expansion for the periodic Anderson model with infinite Coulomb repulsion ($U=\infty $) is considered here for an hypercubic lattice of infinite dimension ($d=\infty $). The same type of simplifications obtained by Metzner for the cumulant expansion of the Hubbard model in the limit of $d=\infty $, are shown to be also valid for the

A. Lusakowski, L. A. Turski

We consider two-dimensional degenerate electron gas in the presence of perpendicular random magnetic field. The magnetic field disorder which is assumed to be gaussian is characterized by two parameters. The first is proportional to the amplitude of local magnetic field fluctuations. The second one characterizes the disorder on the longer scale - we call it

M. A. N. Araujo, M. Dzierzawa, C. Aebischer, D. Baeriswyl

We discuss the effect of disorder on the coherent propagation of the bound state of two attracting particles. It is shown that a result analogous to the Anderson theorem for dirty superconductors is also valid for the Cooper problem, namely, that the pair wave function is extended beyond the single-particle localization length if the latter is large. A physi

G. Goldoni, F. Rossi, E. Molinari

We propose that the recently realized T-shaped semiconductor quantum wires (T-wires) could be exploited as three-terminal quantum interference devices. T-wires are formed by intersecting two quantum wells (QWs). By use of a scattering matrix approach and the Landauer-Büttiker theory, we calculate the conductance for ballistic transport in the parent QWs and

W. Wonneberger, R. Lamche

The coupled non-radiative excitations of the electromagnetic field and phasons in films with a quasi one-dimensional charge density wave (CDW) are evaluated for P--polarization and CDW conducting axis inside the film. The prominent features are two surface phason-polariton branches extending from the CDW pinning frequency to the frequency of the longitudinal

James Chiang, Charles D. Dermer

The flaring and fading radio, optical, and X-ray afterglows from GRB 970508 are modeled by a highly relativistic plasma sphere which decelerates by sweeping up ambient gas. The afterglow emission is assumed to be synchrotron radiation emitted by nonthermal electrons in the magnetized plasmoid. The temporal behavior of the delayed emission is controlled by th

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

We present results on the X-ray spectrum of the quasar PG 1114+445 from an ASCA observation performed in 1996 June, and a ROSAT observation performed 3 years earlier. We show good agreement between all the datasets can be obtained if the underlying continuum in the 0.2--10 keV band is assumed to be a powerlaw (photon index Gamma approx 1.8) absorbed by photo

C. J. Benesh, C. J. Horowitz

The potential enhancement of the cross section $ν\barν\to e^+e^-$ in the presence of a magnetic field is of critical interest for the study of supernovae and as a possible mechanism for gamma ray bursts. While parity violation(PV) in this reaction in free space is forbidden by CP, the presence of a CP non-invariant background gas of electrons creates an asym

Bob Mann, John Peacock, Alan Heavens

We investigate the effects on cosmological clustering statistics of empirical biasing, where the galaxy distribution is a local transformation of the present-day Eulerian density field. The effects of the suppression of galaxy numbers in voids, and their enhancement in regions of high density, are considered, independently and in combination. We compare resu

K. Nandra, I. M. George, R. F. Mushotzky, T. J. Turner

We present evidence for changes in the strength and profile of the iron K-alpha line in Active Galactic Nuclei (AGN), based on X-ray observations with ASCA. There is a clear decrease in the strength of the line with increasing luminosity. This relation is is not due solely to radio power, as it persists when only radio-quiet AGN are considered and therefore

Burkhard Fuchs

Using recent observations of the kinematics of the disk stars the dynamical state of the disk of NGC 488 is discussed. The disk is shown to be dynamically `cool&#39;, so that NGC 488 cannot have experienced many -- even minor -- mergers in the past.

B. Fuchs, S. von Linden

We examine the local stability of galactic discs against axisymmetric density perturbations with special attention to the different dynamics of the stellar and gaseous components. In particular the discs of the Milky Way and of NGC 6946 are studied. The Milky Way is shown to be stable, whereas the inner parts of NGC 6946, a typical Sc galaxy from the Kennicu

Frank C. van den Bosch, Walter Jaffe, Roeland P. van der Marel

We present multi-colour (U, V and I) photometry obtained with the second Wide Field and Planetary Camera (WFPC2) on the Hubble Space Telescope (HST), and spectra taken with the William Herschel Telescope (WHT) and the HST Faint Object Spectrograph (FOS), for the early-type galaxies NGC 4342 and NGC 4570. These galaxies are intermediate between ellipticals an

Henry E. Kandrup

This paper proposes a geometric interpretation of flows generated by the collisionless Boltzmann equation (CBE), focusing on the coarse-grained approach towards equilibrium. The CBE is a noncanonical Hamiltonian system with the distribution function f the fundamental dynamical variable, the mean field energy H[f] playing the role of the Hamiltonian and the n

Duncan Forbes, Carl Grillmair, Gerard Williger, R. Elson

The Fornax cluster galaxies NGC 1399 and NGC 1404 are ideal for studying the effects of a cluster environment on globular cluster systems. Here we present new optical imaging of these two galaxies from both the Hubble Space Telescope&#39;s Wide Field and Planetary Camera 2 and the Cerro Tololo Inter-American Observatory&#39;s 1.5m telescope. The combination

James Binney, Ing-Guey Jiang, Suvendra Dutta

We study the persistence of warps in galactic discs in the presence of massive halos. A disc is approximated by a set of massive rings, while a halo is represented by a conventional n-body simulation. We confirm the conclusion of Nelson & Tremaine (1995) that a halo responds strongly to an embedded precessing disc. This response invalidates the approximation

R. Alvarez, M-O. Mennessier, D. Barthes, X. luri

HIPPARCOS astrometric and kinematical data of oxygen-rich Mira variables are used to calibrate absolute near-infrared magnitudes and kinematic parameters. Two sets of near-infrared magnitudes compiled from different authors are used: broad-band K and narrow-band photometric measurements at 1.04 micron (104 filter). Three distinct classes of stars with differ

J. P. Halpern, M. Eracleous, K. Forster

We obtained new ROSAT HRI and optical observations in the field of the Einstein X-ray source E 0336-248, which we use to identify it as a 19th magnitude BL Lacertae object at z=0.251 with an X-ray luminosity of 10^45 erg/s. It is also a 14 mJy radio source at 20 cm. An emission-line galaxy at z=0.043 that was previously considered a Seyfert identification fo

Max Tegmark

Upcoming large redshift surveys potentially allow precision measurements of the galaxy power spectrum. To accurately measure P(k) on the largest scales, comparable to the depth of the survey, it is crucial that finite volume effects are accurately corrected for in the data analysis. Here we derive analytic expressions for the one such effect that has not pre

M. Asakawa, T. Csorgo

We discuss the possibility to observe hadron modification in hot and dense matter via the correlation of identical particles. We find that a modification of hadronic masses in medium leads to two-mode squeezing which signals itself in a back-to-back correlations of hadrons. This effect leads to a signal of a shift of $\phi$-meson mass.

I E Bulyzhenkov

Three variational vector equations are derived for the extended particle-field object located on the light cone. Point sources are excluded from the pure field equations and all physical magnitudes are free from divergences. Accepting 3D intersections of 4D cone-charges, vector electrogravity explains all observed phenomena under common flat 3D and 1D interv

Edward R. Floyd

The reflection time, during which a particle is in the classically forbidden region, is described by the trajectory representation for reflection by a semi-infinite rectangular barrier. The Schrödinger wave function has microstates for such reflection. The reflection time is a function of the microstate. For oblique reflection, the Goos-Hänchen displacement

M. Ciuchini, R. Contino, E. Franco, G. Martinelli

Long-distance contributions of operators of the effective non-leptonic weak Hamiltonian containing charmed currents have been recently studied. Penguin-like contractions of these operators, denoted as charming penguins, have been shown to be relevant for several B decays into two pseudoscalar mesons. In particular, they are expected to give large enhancement

Dong Pyo Chi, Jinsoo Kim

In this paper we give a quantum mechanical algorithm that can search a database by a single query, when the number of solutions is more than a quarter. It utilizes modified Grover operator of arbitrary phase.

P. Bamert

In this talk I summarize recent work done in collaboration with Cliff Burgess and Denis Michaud, in which we performed a detailed investigation of how solar neutrinos propagate through helioseismic waves. We find that the MSW solar neutrino spectrum is not modified at all in the presence of seismic waves. This finding differs from earlier estimates mainly be

A. I. Sanda, Zhi-zhong Xing

We consider three possible scenarios of new physics in B^0_d-\bar{B}^0_d mixing and propose a simple framework for analyzing their effects. This framework allows us to study the CP asymmetry in semileptonic B_d decays ({\cal A}_{SL}) and those in nonleptonic transitions such as B_d \to J/ψK_S and B_d \to π^+π^-. Numerically we find that new physics may enhan

R. Balasubramanian, S. V. Dhurandhar

The paper deals with the estimation of parameters of gravitational waves from coalescing binaries. It explains the discrepancy between the Monte carlo simulations and the covariance matrix. We include the post-Newtonian as well as the Newtonian case.

S. Ispolatov, P. L. Krapivsky, S. Redner

A dynamical model of capital exchange is introduced in which a specified amount of capital is exchanged between two individuals when they meet. The resulting time dependent wealth distributions are determined for a variety of exchange rules. For ``greedy&#39;&#39; exchange, an interaction between a rich and a poor individual results in the rich taking a spec

Eric G. Blackman, Tom Chou

We generalize the mean field magnetic dynamo to include local evolution of the mean vorticity in addition to the mean magnetic field. The coupled equations exhibit a general mean field dynamo instability that enables the transfer of turbulent energy to the magnetic field and vorticity on larger scales. The growth of the vorticity and magnetic field both requ

Rupert A. C. Croft, David H. Weinberg, Neal Katz, Lars Hernquist

We present a method to recover the shape and amplitude of the power spectrum of mass fluctuations, P(k), from observations of the high redshift \lya forest. The method is motivated by the physical picture of the \lya forest that has emerged from hydrodynamic cosmological simulations and related semi-analytic models, which predicts a tight correlation between

The MACHO Collaboration, K. H. Cook, C. Alcock, R. A. Allsman

The MACHO Project monitors millions of stars in the Large Magellanic Cloud, the Small Magellanic Cloud and the bulge of the Milky Way searching for the gravitational microlensing signature of baryonic dark matter. This Project has yielded surprising results. An analysis of two years of data monitoring the Large Magellanic Cloud points to {$\sim 50%$} of the

Vadim Schechtman

The aim of this note is to give a simple definition of genus zero virtual orientation classes (or fundamental classes) for projective complete intersections or, more generally, for complete intersections in convex varieties, and to prove a push forward formula for them.

G. Steigman, N. Hata, J. E. Felten

Because the baryon-to-photon ratio eta_{10} is in some doubt, we drop nucleosynthetic constraints on eta_{10} and fit the three cosmological parameters (h, Omega_M, eta_{10}) to four observational constraints: Hubble parameter h_o = 0.70+-0.15, age of the universe t_o = 14+7-2 Gyr, cluster gas fraction f_o \equiv f_G h^{3/2} = 0.060 +- 0.006, and effective s

Boris Kastening

Pad&#39;e approximants are used to improve the convergence behavior of perturbative results in massless scalar and gauge field theories at finite temperature.

Stavros Garoufalidis, Nathan Habegger

This is a revised version (replacing an older one) with typos fixed and the introduction expanded.

Mark Andrea A. de Cataldo

We prove a multiple-points higher-jets nonvanishing theorem by the use of local Seshadri constants. Applications are given to effectivity problems such as constructing rational and birational maps into Grassmannians, and the global generation of vector bundles.

Mark Andrea A. de Cataldo

We introduce a notion of singular hermitian metrics (s.h.m.) for holomorphic vector bundles and define positivity in view of $L^2$-estimates. Associated with a suitably positive s.h.m. there is a (coherent) sheaf 0-th kernel of a certain $d&#39;&#39;$-complex. We prove a vanishing theorem for the cohomology of this sheaf. All this generalizes to the case of

Yun Wang, David N. Spergel, Edwin L. Turner

Low amplitude (linear regime) cosmic density fluctuations lead to spatial variations in the locally measurable value of $H_0$ (denoted as $H_L$), $δ_H \equiv (H_L-H_0)/H_0$, which are of order 3-6% (95% confidence interval) in a sphere of 200$ h^{-1}$Mpc in diameter, and of order 1-2% in a sphere of 400$ h^{-1}$Mpc in diameter, for three currently viable str

Steven S. Gubser, Igor R. Klebanov

We study how coincident Dirichlet 3-branes absorb incident gravitons polarized along their world volume. We show that the absorption cross-section is determined by the central term in the correlator of two stress-energy tensors. The existence of a non-renormalization theorem for this central charge in four-dimensional N=4 supersymmetric Yang-Mills theories s

Conor Houghton, Paul Sutcliffe

We discuss the ADHMN construction for SU(N) monopoles and show that a particular simplification arises in studying charge N-1 monopoles with minimal symmetry breaking. Using this we construct families of tetrahedrally symmetric SU(4) and SU(5) monopoles. In the moduli space approximation, the SU(4) one-parameter family describes a novel dynamics where the mo

Dmitri Sorokin, Paul K. Townsend

The algebra of Noether supercharges of the M-5-brane effective action is shown to include both 2-form and 5-form central charges. Surprisingly, only the 5-form charge is entirely due to the Wess-Zumino term because the `naive&#39; algebra is the M-2-brane supertranslation algebra. The full structure of central charges is shown to be directly related to the p

Pran Nath

A review of the current status of SUSY/SUGRA/String phenomenology is given.

R. Szalapski

It is possible to place direct constraints on WW-photon and WWZ couplings by studying their tree-level contributions to the process e^+e^- ---> W^+W^-. However, these couplings also contribute at the loop level to e^+e^- ---> f fbar processes where `f&#39; is any Standard-Model fermion. In this paper the available LEP1.5 and LEP2 data, the anticipated LEP2 d

K. Goulianos

We compare results on diffractive W-boson production at the Tevatron with predictions based on the diffractive structure function measured in deep inelastic scattering at HERA assuming (a) conventional factorization or (b) hard factorization combined with a rapidity gap distribution scaled to the total gap probability. We find that conventional factorization

K. Goulianos

Results on hard diffraction from HERA and proton-antiproton Colliders are reviewed with emphasis on the factorization properties of the diffractive structure function of the proton and on the structure of the pomeron.

Michael Stone

This is the text of a talk which is to be published in the proceedings of the Joint APCTP-ICTP conference (Seoul National University Korea, May 26th-30th 1997).

S. Roche, Guy Trambly de Laissardiere, D. Mayou

We present a review of some results concerning electronic transport properties of quasicrystals. After a short introduction to the basic concepts of quasiperiodicity, we consider the experimental transport properties of electrical conductivity with particular focus on the effect of temperature, magnetic field and defects. Then, we present some heuristic appr

R. R. Shcherbakov

The recently introduced self-organizing height-arrow (HA) model is numerically investigated on the square lattice and analytically on the Bethe lattice. The concentration of occupied sites and critical exponents of distributions of avalanches are evaluated for two slightly different versions of the model. The obtained exponents for distributions of avalanche

S. Roche, D. Mayou

We develop a new real-space method which allows to evaluate the Kubo-Greenwood conductivity of independent electrons in static aperiodic potentials. We apply it to a numerical study of propagation modes in 3 dimensional quasiperiodic systems. The effect of quenched disorder is analysed and for Fermi energies in pseudo-gaps, the conductivity can be stable or

Jian-Sheng Wang

Random sequential adsorption is an irreversible surface deposition of extended objects. In systems with continuous degrees of freedom coverage follows a power law, theta(t) = theta_J - c t^{-alpha}, where the exponent alpha depends on the geometric shape (symmetry) of the objects. Lattice models give typically exponential saturation to jamming coverage. We d

Somnath Bharadwaj, Dipak Munshi, Tarun Souradeep

In the context of inflationary scenarios, the observed large angle anisotropy of the Cosmic Microwave Background (CMB) temperature is believed to probe the primordial metric perturbations from inflation. Although the perturbations from inflation are expected to be gaussian random fields, there remains the possibility that nonlinear processes at later epochs

James A. Carlson, Domingo Toledo

We show that the kernel of the monodromy representation for hypersurfaces of degree d and dimension n is large for d at least three with the exception of the cases (d,n) = (3,0) and (3,1). For these the kernel is finite. By &#34;large&#34; we mean a group that admits a homomorphism to a semisimple Lie group of noncompact type with Zariski-dense image. By the

R. Mennicken, A. K. Motovilov

We consider operator matrices {\bf H}= (A_0 B_{01} \\ B_{10} A_{1}) with self-adjoint entries A_i, i=0,1, and bounded B_{01}=B_{10}^*, acting in the orthogonal sum {\cal H}={\cal H}_0\oplus{\cal H}_1 of Hilbert spaces {\cal H}_0 and {\cal H}_1. We are especially interested in the case where the spectrum of, say, A_1 is partly or totally embedded into the con

T. Graber, R. Pandharipande

We prove a localization formula for virtual fundamental classes in the context of torus equivariant perfect obstruction theories. As an application, the higher genus Gromov-Witten invariants of projective space are expressed as graph sums of tautological integrals over moduli spaces of stable pointed curves (generalizing Kontsevich&#39;s genus 0 formulas). A

Udo Hertrich-Jeromin

Classically, isothermic surfaces are characterized as those surfaces which are &#34;divisible into infinitesimal squares by their curvature lines&#34;. This characterization is the direct analogue to the definition of discrete isothermic nets. In order to understand the relations between the discrete and the smooth theory better, it is described how to give

F. A. Bais, B. J. Schroers

Magnetic monopoles in Yang-Mills-Higgs theory with a non-abelian unbroken gauge group are classified by holomorphic charges in addition to the topological charges familiar from the abelian case. As a result the moduli spaces of monopoles of given topological charge are stratified according to the holomorphic charges. Here the physical consequences of the str

A. Avella, F. Mancini, D. Villani, L. Siurakshina

The two-dimensional Hubbard model is analyzed in the framework of the two-pole expansion. It is demonstrated that several theoretical approaches, when considered at their lowest level, are all equivalent and share the property of satisfying the conservation of the first four spectral momenta. It emerges that the various methods differ only in the way of fixi

N. E. Mavromatos, D. V. Nanopoulos

We discuss possible quantum mechanical aspects of MicroTubules (MT), based on recent developments in quantum physics.We focus on potential mechanisms for `energy-loss-free&#39; transport along the microtubules, which could be considered as realizations of Fröhlich&#39;s ideas on the rôle of solitons for superconductivity and/or biological matter. By represen

G. Barenboim, F. J. Botella

In this work we analyze a new piece present in the $ΔF = 2$ effective Lagrangian in models with extra vector-like quarks. This piece, which was not taken into account previously, is required in order to preserve gauge invariance once the unitarity of the CKM matrix is lost. We illustrate the effects of this new piece in both, CP conserving and CP violating p

C. Charmousis, B. Boisseau, B. Linet

We consider a self-gravitating string generated by a global vortex solution in general relativity. We investigate the Einstein and field equations of a global vortex in the region of its central line and at a distance from the centre of the order of the inverse of its Higgs boson mass. By combining the two we establish by a limiting process of large Higgs ma

Ashoke Sen

We study some aspects of the strong coupling dynamics of Dirichlet six branes, anti- six branes, and orientifold planes by using the equivalence of type IIA string theory and M-theory on S^1. In the strong coupling limit there exists static configuration of brane and anti-brane at arbitrary separation, suspended in an external magnetic field. The mass of the

Mark Hindmarsh, Allen Everett

The generation of primordial magnetic fields from cosmological phase transitions is discussed, paying particular attention to the electroweak transition and to the various definitions of the `average&#39; field that have been put forward. It is emphasised that only the volume average has dynamical significance as a seed for galactic dynamos. On rather genera

V. V. Kiselev

In the model with the spontaneous breaking of chiral gauge symmetry, the vacuum structure for the pair of Higgs fields can provide the introduction of two generations of fermions. The mixing matrix of charged currents is determined.

H. -W. Lee, Doochul Kim

We study a class of super-rough growth models whose structure factor satisfies the Family-Vicsek scaling. We demonstrate that a macroscopic background spontaneously develops in the local surface profile, which dominates the scaling of the local surface width and the height-difference. The shape of the macroscopic background takes a form of a finite-order pol

Wu Yue-Liang, Zhou Guang-Zhao

A unification model for strong, electromagnetic, weak and gravitational forces is proposed. The tangent space of ordinary coordinate 4-dimensional spacetime is a submanifold of an 14-dimensional internal spacetime spanned by four frame fields. The unification of the standard model with gravity is governed by gauge symmetry in the internal spacetime.

Guy F. de Teramond, Randall Espinoza, Manuel Ortega-Rodriguez

The anomalous behavior of the spin-spin correlation at large momentum transfer in pp elastic scattering is described in terms of the degrees of freedom associated with the onset of the charm threshold. A non-perturbative analysis based on the symmetries of QCD is used to extract the relevant dynamics of the charmonium-proton interaction. The enhancement to p

Machiko Hatsuda, Kiyoshi Kamimura

We present the covariant BRST quantization of the super-D-string. The non-vanishing supersymmetric U(1) field strength ${\cal F}$ is essential for the covariant quantization of the super-D-string as well as for its static picture. A SO(2) parameter parametrizes a family of local supersymmetric (kappa symmetric) systems including the super-D-string with ${\ca

S. Bose, V. Vedral, P. L. Knight

We generalize the procedure of entanglement swapping to obtain a scheme for manipulating entanglement in multiparticle systems. We describe how this scheme allows to establish multiparticle entanglement between particles belonging to distant users in a communication network through a prior distribution of singlets followed by only local measurements. We show

S. Bose, K. Jacobs, P. L. Knight

We describe how a quantum system composed of a cavity field interacting with a movable mirror can be utilized to generate a large variety of nonclassical states of both the cavity field and the mirror. First we consider state preparation of the cavity field. The system dynamics will prepare a single mode of the cavity field in a multicomponent Schrödinger ca

Karl-Peter Marzlin, J&#34;urgen Audretsch

We present a new theoretical method to study a trapped gas of bosonic two-level atoms interacting with a single mode of a microwave cavity. This interaction is described by a trilinear Hamiltonian which is formally completely equivalent to the one describing parametric down-conversion in quantum optics. A system of differential equations describing the evolu