September 2001 arXiv papers — page 11

Scott Dodelson, Ewan Stewart

Recent observations suggest that the spectral index of the primordial perturbations is very close to unity, as expected in models of slow roll inflation. It is still possible for such models to produce spectra which are scale dependent. We present a formula for the spectrum produced by an arbitrary inflaton potential (within the context of slow roll models);

M. Ruderman

Modeling the dynamics of the quantum fluids within a spinning-down neutron star gives a description consistent with observed pulsar magnetic field evolution and spin-period "glitches." The long-standing problem of large predicted excesses in spin-down sustained pulsar heating from such models now see ms resolvable. However, the origin of some pulsar

Michael E. Jones

The Arcminute MicroKelvin Imager (AMI) is an instrument currently under construction in Cambridge designed to produce a survey of galaxy clusters via the Sunyaev-Zel'dovich effect. It consists of two interferometric arrays, both operating at 12-18 GHz; one of ten 3.7-m antennas to provide good temperature sensitivity to arcminute-scale structures, and on

David Polarski

The present paradigm in cosmology is the usual Big-Bang Cosmology in which two stages of accelerated expansion are incorporated: the inflationary phase in the very early universe which produces the classical inhomogeneities observed in the universe, and a second stage of acceleration at the present time as the latest Supernovae observations seem to imply. Bo

R. -D. Scholz, G. P. Szokoly, M. Andersen, R. Ibata

We report the discovery of a wide pair (93 arcsec angular separation) of extremely cool ($T_{eff}<4000$ K) white dwarfs with a very large common proper motion ($\sim1.9$ arcsec/yr). The objects were discovered in a high proper motion survey in the poorly investigated southern sky region with $δ<-60^{\circ}$ using SuperCOSMOS Sky Survey (SSS) data. Both objec

R. Benton Metcalf

I argue that the cold dark matter (CDM) model requires that even within a few kpc of the center of a galactic halo a significant fraction (greater than a few percent) of the surface density is contained in substructures with masses > 10^3 solar masses. These structures should be light enough to avoid dynamical friction and dense enough to avoid tidal disrupt

P. T. O&#39;Brien, K. Page, J. N. Reeves, K. Pounds

We present XMM-Newton observations of Mrk 359, the first Narrow Line Seyfert 1 galaxy discovered. Even among NLS1s, Mrk 359 is an extreme case with extraordinarily narrow optical emission lines. The XMM-Newton data show that Mrk 359 has a significant soft X-ray excess which displays only weak absorption and emission features. The (2-10) keV continuum, includ

M. Landgraf

Meteoroids originating from the local interstellar medium, traverse the solar system. This has been proven by in situ measurements by interplanetary spacecraft as well as highly sensitive radar measurements. Early attempts to detect interstellar meteoroids using the instruments on board the Pioneer 8 and 9 spacecraft failed. More sensitive detectors on board

W. A. Dziembowski, Philip R. Goode

We describe systematic changes in the centroid frequencies and the splitting coefficients as found using data from MDI on board SOHO, covering cycle 23. The data allow us to construct a seismic map of the evolving solar activity -- covering all latitudes. At lower latitudes, the temporal evolution closely tracks that of {\it butterfly diagram}. The additiona

Angela C. Taylor

The Very Small Array (VSA) is a fourteen-element interferometer designed to study the cosmic microwave background on angular scales of 2.4 to 0.2 degrees (angular multipoles l = 150 to 1800). It operates at frequencies between 26 and 36 GHz, with a bandwidth of 1.5 GHz, and is situated at the Teide Observatory, Tenerife. The instrument also incorporates a si

M. Paolillo, G. Fabbiano, G. Peres, D. -W. Kim

We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax cluster. Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple Beta model and suggests instead three distinct components. We use a multi-component

Gilles Bergond, Stephane Leon, Jean Guibert

We have investigated the 2-D stellar distribution in the outer parts of three nearby open clusters: NGC 2287 (=M41), NGC 2516, and NGC 2548 (=M48). Wide-field star counts have been performed in two colours on pairs of digitized ESO and SRC Schmidt plates, allowing us to select likely cluster members in the colour-magnitude diagrams. Cluster tidal extensions

Nicole M. Lloyd-Ronning, Vahe&#39; Petrosian

In this paper, we explore time resolved Gamma-Ray Burst (GRB) spectra in the context of the synchrotron emission model presented in Lloyd and Petrosian (2000; LP00). First, we show that our model - which involves three distinct emission regimes - can provide excellent fits to the time resolved spectra of GRBs, and we present these results for a few bursts. W

J. Malzac, P. O. Petrucci

We consider the possibility that most of the reflection component, observed in the hard X-ray spectra of Seyfert galaxies, could be formed on an extended medium, at large distance from the central source of primary radiation (e.g. on a torus). Then, the reflector cannot respond to the rapid fluctuations of the primary source. The observed reflected flux is c

G. B. Taylor, A. C. Fabian, S. W. Allen

We present multi-frequency VLA observations of the radio galaxy PKS 1246-410 at the center of the Centaurus Cluster, and compare these results to recent Chandra observations. The unusual radio morphology of PKS 1246-410 probably results from interactions with the hot, X-ray emitting gas. This gas, along with cluster magnetic fields, also produces substantial

A. Lecavelier des Etangs, T. X. Thuan, Y. I. Izotov

FUSE far-UV spectroscopy of the nearby metal-deficient (Zo/8) cometary Blue Compact Dwarf galaxy Mrk59 have been used to investigate element abundances in its interstellar medium. The lack of diffuse H2 (N(H2)<10e15 cm-2) is due to the combined effect of a strong UV radiation field and a low metallicity. By fitting the line profiles with multiple components

Takuji Tsujimoto, Toshikazu Shigeyama, Yuzuru Yoshii

We investigate the chemical evolution of odd-numbered elements such as sodium (Na) and aluminum (Al) during the early epochs of the Galactic halo with the use of a model that reproduces the observed box-shaped distribution of extremely metal-poor stars in the [Na, Al/Mg] versus [Mg/H] plane. Our model is constructed under the assumptions that those stars ret

Takuji Tsujimoto, Toshikazu Shigeyama

The origin of nucleosynthesis products of rapid neutron capture reactions (the r-process) is a longstanding astrophysical problem. Recent analyses of elemental abundances for extremely metal-poor stars shed light on the elemental abundances of individual supernovae. Comparison of the abundance distributions of some extremely metal-poor stars with those of th

T. R. Geballe, G. R. Knapp, S. K. Leggett, X. Fan

We use new and published medium resolution 0.6--2.5 $μ$m spectra of L and T dwarfs to develop a unified classification system for both of these new spectral classes. Two indices of the system at 1.2 $μ$m and 1.5 $μ$m are based on nearby absorption bands of water vapor and two are associated with methane bands near 1.6 $μ$m and 2.2 $μ$m. The 1.5 $μ$m index is

Tsvi Piran, Pawan Kumar, Alin Panaitescu, Luigi Piro

The energy release in gamma-ray bursts is one of the most interesting clues on the nature of their &#34;inner engines&#34;. We show here that the total energy release in GRBs varies by less than one order of magnitude from one burst to another while the energy emitted in $γ$-ray photons varies by more than an order of magnitude. This result indicates that th

L. H. Li, S. Sofia

A magnetic flux tube may be considered both as a separate body and as a confined field. As a field, it is affected both by the cyclonic convection ($α$-effect) and differential rotation ($Ω$-effect). As a body, the tube experiences not only a buoyant force, but also a dynamic pressure due to downflows above the tube. When these two dynamic effects are incorp

E. L. Chapin, D. H. Hughes, B. D. Kelly, W. S. Holland

A robust measurement of the clustering amplitude of the sub-mm population of starburst galaxies requires large-area surveys (>> 1 deg^2). The largest-format arrays subtend only 10 arcmin^2 on the sky and hence scan-mapping is a necessary observing mode. Providing realistic representations of the extragalactic sky and atmosphere, as the input to a detailed si

B. C. Tiburzi, G. A. Miller

We explore skewed parton distributions for two-body, light-front wave functions. In order to access all kinematical regimes, we adopt a covariant Bethe-Salpeter approach, which makes use of the underlying equation of motion (here the Weinberg equation) and its Green&#39;s function. Such an approach allows for the consistent treatment of the non-wave function

Arif Babul, Michael L. Balogh, Geraint F. Lewis, Gregory B. Poole

Within the standard framework of structure formation, where clusters and groups of galaxies are built up from the merging of smaller systems, the physical properties of the intracluster medium, such as the gas temperature and the total X-ray luminosity, are predicted to possess well defined self-similar scaling relations. Observed clusters and groups, howeve

S. K. Lamoreaux

In 1968, F.L. Shapiro published the suggestion that one could search for an electron EDM by applying a strong electric field to a substance that has an unpaired electron spin; at low temperature, the EDM interaction would lead to a net sample magnetization that can be detected with a SQUID magnetometer. One experimental EDM search based on this technique was

A. Schwenk, G. E. Brown, B. Friman

We use the induced interaction of Babu and Brown to derive two novel relations between the quasiparticle interaction in nuclear matter and the unique low momentum nucleon-nucleon interaction V_low k in vacuum. These relations provide two independent constraints on the Fermi liquid parameters of nuclear matter. We derive the full renormalization group equatio

Thierry Giordano, Vladimir Pestov

A topological group $G$ is extremely amenable if every continuous action of $G$ on a compact space has a fixed point. Using the concentration of measure techniques developed by Gromov and Milman, we prove that the group of automorphisms of a Lebesgue space with a non-atomic measure is extremely amenable with the weak topology but not with the uniform one. St

C. Bernard, P. Williams, S. Datta, Steven Gottlieb

We compute the leptonic decay constants of heavy-light vector mesons in the quenched approximation. The reliability of lattice computations for heavy quarks is checked by comparing the ratio of vector to pseudoscalar decay constant with the prediction of Heavy Quark Effective Theory in the limit of infinitely heavy quark mass. Good agreement is found. We the

Andrei Mudrov, Konstantin Varnashev

Within the four-loop $\ve$ expansion, we study the critical behavior of certain antiferromagnets with complicated ordering. We show that an anisotropic stable fixed point governs the phase transitions with new critical exponents. This is supported by the estimate of critical dimensionality $N_c^C=1.445(20)$ obtained from six loops via the exact relation $N_c

Sven Soff, Steffen A. Bass, David H. Hardtke, Sergey Y. Panitkin

We calculate the kaon HBT radius parameters for high energy heavy ion collisions, assuming a first order phase transition from a thermalized Quark-Gluon-Plasma to a gas of hadrons. At high transverse momenta K_T ~ 1 GeV/c direct emission from the phase boundary becomes important, the emission duration signal, i.e., the R_out/R_side ratio, and its sensitivity

Andrei Parnachev, David A. Sahakyan

We investigate the relation between the algebraic construction of boundary states in AdS_3 and the target space analysis of D-branes and show the consistency of the two descriptions. We compute, in the semiclassical regime, the overlap of a localized closed string state with boundary states and identify the latter with D-branes wrapping conjugacy classes in

Edward A. Baltz, Joakim Edsjo, Katherine Freese, Paolo Gondolo

Using a new instrument, the HEAT collaboration has confirmed the excess of cosmic ray positrons that they first detected in 1994. We explore the possibility that this excess is due to the annihilation of neutralino dark matter in the galactic halo. We confirm that neutralino annihilation can produce enough positrons to make up the measured excess only if the

T. A. Costi, N. Manini

We solve the $S=1/2$ Kondo lattice model within the dynamical mean field theory. Detailed predictions are made for the dependence of the lattice Kondo resonance and the conduction electron spectral density on temperature and band filling $n_{c}$. Two low-energy scales are identified in the spectra: a renormalized hybridization pseudogap scale $T^{*}$, which

P. Monaco, T. Theuns, G. Taffoni

PINOCCHIO (PINpointing Orbit-Crossing Collapsed Hierarchical Objects) is a new algorithm for identifying dark matter halos in a given numerical realisation of the linear density field in a hierarchical universe (Monaco et al. 2001). It is shown that Lagrangian perturbation theory, and in particular its ellipsoidal truncation, is able to predict accurately th

Moncy V. John

A modified de Broglie-Bohm (dBB) approach to quantum mechanics is presented. In this new deterministic theory, which uses complex methods in an intermediate step, the problem of zero velocity for bound states encountered in the dBB formulation does not appear. Also this approach is equivalent to standard quantum mechanics when averages of dynamical variables

W. M. Lane, F. H. Briggs

As part of a larger program to identify low redshift radio analogues of the damped Lyman-alpha (DLA) absorbers seen in the spectra of high redshift quasars, Westerbork Synthesis Radio Telescope (WSRT) observations have discovered two new HI 21cm absorption lines at z=0.394 and z=0.437 in the spectra of the radio sources B 0248+430 and B 1243-072 respectively

Alessandro Strumia, Francesco Vissani

We estimate how well we will know the parameters of solar neutrino oscillations after KamLAND and Borexino. The expected error on Delta m^2 is few per-mille in the VO and QVO regions, few per-cent in the LMA region, and around 10% in the LOW region. The expected error on sin^2 2theta is around 5%. KamLAND and Borexino will tell unambiguously which specific n

P. Thalmeier, K. Maki

There are now many nodal superconductors in heavy fermion (HF) systems, charge conjugated organic metals, high Tc cuprates and ruthenates. On the other hand only few of them have a well established gap function. We present here a study of the angular dependent thermal conductivity in the vortex state of some of the nodal superconductors. We hope it will help

L. Feher, B. G. Pusztai

A dynamical $r$-matrix is associated with every self-dual Lie algebra $\A$ which is graded by finite-dimensional subspaces as $\A=\oplus_{n \in \cZ} \A_n$, where $\A_n$ is dual to $\A_{-n}$ with respect to the invariant scalar product on $\A$, and $\A_0$ admits a nonempty open subset $\check \A_0$ for which $\ad κ$ is invertible on $\A_n$ if $n\neq 0$ and $κ

G. N. Ord, J. A. Gualtieri

We show that it is possible to construct the Feynman Propagator in one dimension, without quantization, from a single continuous space-time path.

B. Derrida, J. L. Lebowitz, E. R. Speer

We consider an open one dimensional lattice gas on sites $i=1,...,N$, with particles jumping independently with rate 1 to neighboring interior empty sites, the {\it simple symmetric exclusion process}. The particle fluxes at the left and right boundaries, corresponding to exchanges with reservoirs at different chemical potentials, create a stationary nonequi

M. Grasso, N. Sandulescu, Nguyen Van Giai, R. J. Liotta

The Hartree-Fock-Bogoliubov (HFB) equations in coordinate representation are solved exactly, i.e., with correct asymptotic boundary conditions for the continuous spectrum. The calculations are preformed with effective Skyrme interactions. The exact HFB solutions are compared with HFB calculations based on box boundary conditions and with resonant continuum H

G. Amoros, S. Noguera, J. Portoles

Within the framework of phenomenological Lagrangians we construct the effective action of QCD relevant for the study of semileptonic decays of charmed mesons. Hence we evaluate the form factors of D -> P(0^-) l^+ nu_l at leading order in the 1/N_C expansion and, by demanding their QCD-ruled asymptotic behaviour, we constrain the couplings of the Lagrangian.

Harvendra Singh

We study $T^2$ compactification of massive type IIA supergravity in presence of possible Ramond-Ramond (RR) background fluxes. The resulting theory in D=8 is shown to possess full $SL(2,R)\times SL(2,R)$ T-duality symmetry similar to the massless case. It is shown that elements of duality symmetry interpolate between massive type IIA compactified on $T^2$ an

Ricardo Amorim, Franz A. Farias

We implement the Hamiltonian treatment of a nonAbelian noncommutative gauge theory, considering with some detail the algebraic structure of the noncommutative symmetry group. The first class constraints and Hamiltonian are obtained and their algebra derived, as well as the form of the gauge invariance they impose on the first order action.

Enrico Calloni, Luciano Di Fiore, Giampiero Esposito, Leopoldo Milano

We discuss the possibility of verifying the equivalence principle for the zero-point energy of quantum electrodynamics, by evaluating the force, produced by vacuum fluctuations, acting on a rigid Casimir cavity in a weak gravitational field. The resulting force has opposite direction with respect to the gravitational acceleration; the order of magnitude for

Johannes Ruoff, Adamantios Stavridis, Kostas D. Kokkotas

We present a new derivation of the equations governing the oscillations of slowly rotating relativistic stars. Previous investigations have been mostly carried out in the Regge-Wheeler gauge. However, in this gauge the process of linearizing the Einstein field equations leads to perturbation equations which as such cannot be used to perform numerical time ev

R. Guyon, P. Devillard, T. Martin, I. Safi

A fractional quantum Hall liquid with multiple edges is considered. The computation of transport quantities such as current, noise and noise cross correlations in such multiple edge samples requires the implementation of so called Klein factors, which insure the correct quasiparticle exchange properties. The commutation relations of these factors are obtaine

Nobuyuki Motoyui, Shogo Tominaga, Mitsuru Yamada

We will show that 2-dimensional N=2-extended supersymmetric theory can have solitonic solution using the Hamilton-Jacobi method of classical mechanics. Then it is shown that the Bogomol&#39;nyi mass bound is saturated by these solutions and triangular mass inequality is satisfied. At the end, we will mention domain-wall structure in 3-dimensional spacetime.

J. -M. Gerard, Y. Wiaux

We investigate the possibility of generating sizeable dipole radiations in relativistic theories of gravity. Optimal parameters to observe their effects through the orbital period decay of binary star systems are discussed. Constraints on gravitational couplings beyond general relativity are derived.

E. Pazy, E. Biolatti, T. Calarco, I. D&#39;Amico

We present a solid-state implementation of ultrafast conditional quantum gates. Our proposal for a quantum-computing device is based on the spin degrees of freedom of electrons confined in semiconductor quantum dots, thus benefiting from relatively long decoherence times. More specifically, combining Pauli blocking effects with properly tailored ultrafast la

Sergey A. Cherkis, Anton Kapustin

Relative moduli spaces of periodic monopoles provide novel examples of Asymptotically Locally Flat hyperkahler manifolds. By considering the interactions between well-separated periodic monopoles, we infer the asymptotic behavior of their metrics. When the monopole moduli space is four-dimensional, this construction yields interesting examples of metrics wit

Arvind Borde, L. H. Ford, Thomas A. Roman

This paper initiates a program which seeks to study the allowed spatial distributions of negative energy density in quantum field theory. Here we deal with free fields in Minkowski spacetime. Known restrictions on time integrals of the energy density along geodesics, the averaged weak energy condition and quantum inequalities are reviewed. These restrictions

Masato Ito

Based on the assumption that the warp factor of four-dimensional spacetime and the one of fifth dimension are tied through a parameter $α$, we consider five-dimensional gravity with a 3-brane coupled to a bulk scalar field. For arbitrary value of $α$, the form of the warp factor is implicitly determined by hypergeometric function. Concretely, we show that th

S. S. Avancini, J. R. Marinelli, C. E. de O. Rodrigues

In this work we present a method to build in a systematic way a many-body quon basis state. In particular, we show a closed expression for a given number N of quons, restricted to the permutational symmetric subspace, which belongs to the whole quonic space. The method is applied to two simple problems: the three-dimensional harmonic oscillator and the rotor

Elena R. Loubenets

In the present paper we consider the problem of description of an arbitrary generalized quantum measurement with outcomes in a measurable space. Analyzing the unitary invariants of a measuring process, we present the most general form of a possible integral representation of an instrument, which differs from the representations of an instrument available in

Andrew D. Greentree, T. B. Smith, S. R. de Echaniz, A. V. Durrant

This paper presents a wide-ranging theoretical and experimental study of non-adiabatic transient phenomena in a $Λ$ EIT system when a strong coupling field is rapidly switched on or off. The theoretical treatment uses a Laplace transform approach to solve the time-dependent density matrix equation. The experiments are carried out in a Rb$^{87}$ MOT. The resu

Sergio Albeverio, Shao-Ming Fei, Debashish Goswami

Explicit sufficient and necessary conditions for separability of higher dimensional quantum systems with rank two density matrices are given. A nonseparability inequality is also presented, for the case where one of the eigenvectors corresponding to nonzero eigenvalues is a maximally entangled state.

M. A. Korshunov

The mixed crystal of a para-dibromobenzene with a para-chloronitrobenzene is investigated at concentration of components from 0% up to 60% of a para-chloronitrobenzene by the method of Low-Frequency Raman spectroscopy. It is shown, that in range of concentrations from 25% up to 50% of a para-chloronitrobenzene the spectrum of the mixed crystal would consist

E. Hernandez

An extended Hamiltonian approach to conduct isothermal-isobaric molecular dynamics simulations with full cell flexibility is presented. The components of the metric tensor are used as the fictitious degrees of freedom for the cell, thus avoiding the problem of spurious cell rotations and artificial symmetry breaking effects present in the original Parrinello

F. -R. Carminati, M. Schiavoni, L. Sanchez-Palencia, F. Renzoni

We present a detailed experimental study of a three-dimensional lin$\perp$lin bright optical lattice. Measurements of the atomic temperature and spatial diffusion coefficients are reported for different angles between the lattice beams, i.e. for different lattice constants. The experimental findings are interpretated with the help of numerical simulations. I

Jorge G. Hirsch, Victoria E. Ceron, Octavio Castanos, Peter O. Hess

The pseudo SU(3) approach has been used to describe many low-lying rotational bands, as well as BE(2) and B(M1) intensities in rare earth and actinide nuclei, both with even-even and odd-mass numbers . The double beta half lives of some of these parent nuclei to the ground and excited states of the daughter ones were evaluated for the two and zero neutrino e

J. Terasaki, F. Barranco, P. -F. Bortignon, R. A. Broglia

The influence of particle-phonon coupling on pairing correlations in nuclei is studied by solving the Dyson equation including the anomalous (pairing) Green function. We develop the formalism for solving the equation with the minimum of approximations. The solution of the Dyson equation is compared with the diagonalization of particle-phonon coupled Hamilton

S. Wolf, V. Lisin, R. Kondratiev, A. M. Massone

Compton scattering by the proton has been measured using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new data are interpreted in terms of dispersion theory based on the SAID-SM99K parameterization of photo-meson amplitudes. It is found that two-pion exchange in the t-channel is needed for a description of the dat

Damian H. Zanette

Statistical properties of the taxonomic classification of human languages are studied. It is shown that, at the highest levels of the taxonomic hierarchy, the frequency of taxon members as a function of the number of languages belonging to each member decays as a power law. This feature reveals that a self-similar structure underlies the taxonomy of language

Takeo Kojima

We study the affine $A_{n-1}^{(1)}$ Toda fields with boundary reflection. Our approach is based on the free field approach. We construct free field realizations of the boundary state and its dual. For an application of these realizations, we present integral representations for the form factors of the local operators. In a limiting case $ρ\to \infty$, our in

Oleg Yu. Shvedov

Essential properties of semiclassical approximation for quantum mechanics are viewed as axioms of an abstract semiclassical mechanics. Its symmetry properties are discussed. Semiclassical systems being invariant under Lie groups are considered. An infinitesimal analog of group relation is written. Sufficient conditions for reconstructing semiclassical group

Laszlo Erdos, Vitali Vougalter

We define the two dimensional Pauli operator and identify its core for magnetic fields that are regular Borel measures. The magnetic field is generated by a scalar potential hence we bypass the usual $\bA\in L^2_{loc}$ condition on the vector potential which does not allow to consider such singular fields. We extend the Aharonov-Casher theorem for magnetic f

Jan Snellman

The aim of this paper is sketch a theory of divisibility and factorisation in topological monoids, where finite products are replaced by convergent products. The algebraic case can then be viewed as the special case of discretely topologised topological monoids. In particular, we define the topological factorisation monoid, a generalisation of the factorisat

S. Berman, J. Morita, Y. Yoshii

We introduce the notion of Lie algebras with plus-minus pairs as well as regular plus-minus pairs. These notions deal with certain factorizations in universal enveloping algebras. We show that many important Lie algebras have such pairs and we classify, and give a full treatment of, the three dimensional Lie algebras with plus-minus pairs.

Siegfried Echterhoff, S. Kaliszewski, John Quigg

A coaction d of a locally compact group G on a C*-algebra A is maximal if a certain natural map from A times_d G times_{d hat} G onto A otimes K(L^2(G)) is an isomorphism. All dual coactions on full crossed products by group actions are maximal; a discrete coaction is maximal if and only if A is the full cross-sectional algebra of the corresponding Fell bund

Jae Choon Cha

We study the effect of mutation on link concordance and 3-manifolds. We show that the set of links concordant to sublinks of homology boundary links is not closed under positive mutation. We show that mutation does not preserve homology cobordism classes of 3-manifolds. A significant consequence is that there exist 3-manifolds which have the same quantum SU(

Linus Kramer

We classify compact 2-connected homogeneous spaces with the same rational cohomology as a product of spheres. This classification relies on spectral sequences, homotopy theory, and representation theory. We then apply this classification to two geometric problems. The first problem is the classification of all isoparametric hypersurfaces which admit a transi

Rostyslav O. Hryniv, Yaroslav V. Mykytyuk

Singular Gordon potentials are defined to be distributions from the space W^{-1}_{2,unif}(R) that are sufficiently fast approximated by periodic ones. We prove that Schrödinger operators with singular Gordon potentials have no point spectrum and show that a rich class of quasiperiodic distributions consists of singular Gordon potentials.

Rostyslav O. Hryniv, Yaroslav V. Mykytyuk

We show that formal Schrödinger operators with singular potentials from the space W^{-1}_{2,unif}(R) can be naturally defined to give selfadjoint and bounded below operators, which depend continuously in the uniform resolvent sense on the potential in the W^{-1}_{2,unif}(R)-norm. In the case of periodic singular potentials we also establish pure absolute con

Linus Kramer

We describe some buildings related to complex Kac-Moody groups. First we describe the spherical building of SLn(C) (i.e. the projective geometry PG(Cn)) and its Veronese representation. Next we recall the construction of the affine building associated to a discrete valuation on the rational function field $C(z)$. Then we describe the same building in terms o

Andrew Granville, Izabella Laba, Yang Wang

We consider the problem of characterizing finite sets which tile the integers by translations. Coven and Meyerowitz (J. Algebra 1999) found necessary and sufficient conditions for a finite set A to tile the integers under the assumption that |A| has at most 2 distinct prime factors. The purpose of this article is to settle, for the first time, certain three-

Izabella Laba, Yang Wang

A probability measure in R^d is called a spectral measure if it has an orthonormal basis consisting of exponentials. In this paper we study spectral Cantor measures. We establish a large class of such measures and give a necessary and sufficient condition on the spectrum of a spectral Cantor measure. This extends the earlier results of Jorgensen-Pedersen and

R. Friedman, J. W. Morgan

Let G be a simple and simply connected complex linear algebraic group. In this paper, we discuss the generalization of the parabolic construction of holomorphic principal G-bundles over a smooth elliptic curve to the case of a singular curve of arithmetic genus one and to a fibration of Weierstrass cubics over a base B. Except for G of type E_8, the method g

L. S. Boulton, M. P. Garcia del Moral, I. Martin, A. Restuccia

The spectrum of the Hamiltonian of the double compactified D=11 supermembrane with non-trivial central charge or equivalently the non-commutative symplectic super Maxwell theory is analyzed. In distinction to what occurs for the D=11 supermembrane in Minkowski target space where the bosonic potential presents string-like spikes which render the spectrum of t

Bobby Acharya, Edward Witten

M-theory compactification on a manifold X of $G_2$ holonomy can give chiral fermions in four dimensions only if X is singular. A number of examples of conical singularities that give chiral fermions are known; the present paper is devoted to describing some additional examples. In some of them, the physics can be determined but the metric is not known explic

Chiang-Mei Chen, Dmitri V. Gal&#39;tsov, Sergei A. Sharakin

We investigate non-local dualities between suitably compactified higher-dimensional Einstein gravity and supergravities which can be revealed if one reinterprets the dualised Kaluza-Klein two-forms in $D>4$ as antisymmetric forms belonging to supergravities. We find several examples of such a correspondence including one between the six-dimensional Einstein

Lubos Motl

After a short introduction to Matrix theory, we explain how can one generalize matrix models to describe toroidal compactifications of M-theory and the heterotic vacua with 16 supercharges. This allows us, for the first time in history, to derive the conventional perturbative type IIA string theory known in the 80s within a complete and consistent nonperturb

Pierre van Baal

This talk discusses two topological features in non-abelian gauge theories, related by the notion of abelian projection and the Hopf invariant. Minimising the energy of the non-linear sigma model with a Skyrme-like term (the Faddeev-Niemi model), can be identified with a non-linear maximal abelian gauge fixing of the SU(2) gauge vacua with a winding number e

A. Aste

It is shown that the alternative Klein-Gordon equation with positive definite probability density proposed in a letter by M.D. Kostin does not meet the requirements of relativistic (quantum) field theory and therefore does not allow for a meaningful physical interpretation.

Oleg Yu. Shvedov

Semiclassical Hamiltonian field theory is investigated from the axiomatic point of view. A notion of a semiclassical state is introduced. An &#34;elementary&#34; semiclassical state is specified by a set of classical field configuration and quantum state in this external field. &#34;Composed&#34; semiclassical states viewed as formal superpositions of &#34;e

H. Nicolai, D. I. Olive

The analog of the principal SO(3) subalgebra of a finite dimensional simple Lie algebra can be defined for any hyperbolic Kac Moody algebra g(A) associated with a symmetrizable Cartan matrix A, and coincides with the non-compact group SO(1,2). We exhibit the decomposition of g(A) into representations of SO(1,2); with the exception of the adjoint SO(1,2) alge

Michael McNeil Forbes, Ariel R. Zhitnitsky

We show that several types of global strings occur in colour superconducting quark matter due to the spontaneous violation of relevant U(1) symmetries. These include the baryon U(1)_B, and approximate axial U(1)_A symmetries as well as an approximate U(1)_S arising from kaon condensation. We discuss some general properties of these strings and their interact

D. Schildknecht

The scaling in $σ_{γ^*p}$ cross sections (for $Q^2/W^2 << 1$) in terms of the scaling variable $η= (Q^2 + m^2_0)/Λ^2 (W^2)$ is interpreted in the generalized vector dominance/color-dipole picture (GVD/CDP). The quantity $Λ^2 (W^2)$ is identified as the average gluon transverse momentum absorbed by the $q \bar q$ state, $<\vec l^{~2}> = (1/6) Λ^2 (W^2)$. At a

J. Berges

I review the use of the 2PI effective action in nonequilibrium quantum field theory. The approach enables one to find approximation schemes which circumvent long-standing problems of non-thermal or secular (unbounded) late-time evolutions encountered in standard loop or 1/N expansions of the 1PI effective action. It is shown that late-time thermalization can

Lorenzo Magnea

Dimensional continuation is applied to resummed expressions for the DIS and Drell-Yan partonic cross sections, to regularize the Landau pole. Simple analytic expression are obtained, encoding information about nonperturbative power--suppressed effects.

G. Kramer, H. Spiesberger

The next-to-leading order cross section for the inclusive production of charm quarks in gamma-gamma collisions is calculated as a function of the transverse momentum pT and the rapidity y in approaches using massive or massless charm quarks. For the direct cross section we derive the massless limit from the massive theory with the result that this limit diff

ACFA Linear Collider Working Group

ACFA Linear Collider Working Group report

Wolfgang Lucha, F. F. Schoberl

Studying the Bethe-Salpeter formalism for interactions instantaneous in the rest frame of the bound states described, we show that, for bound-state constituents of arbitrary masses, the mass of the ground state of a given spin may be calculated almost entirely analytically with high accuracy, without the (numerical) diagonalization of the matrix representati

A. V. Berezhnoy, V. V. Kiselev, I. A. Korzhavina, A. K. Likhoded

The cross section of the $D^*$-meson diffractive photoproduction at the HERA collider has been calculated in the framework of perturbatively motivated model for the different kinematic regions. The camparison between the different Pomeron models has been performed.

Konstantin Zyablyuk

This paper has been withdrawn by the author, since most of the results have been published before.

Randy Lewis, Nilmani Mathur, R. M. Woloshyn

The mass differences between spin-1/2 and spin-3/2 baryons are compared to the mass differences between spin-0 and spin-1 mesons. Results of simulations for charmed hadrons in the quenched approximation from a tadpole-improved anisotropic action are discussed in the context of other lattice calculations, quark model predictions, heavy quark symmetry predicti

S. Holtmann, J. Engels, T. Schulze

We investigate the three-dimensional O(2) model on lattices of size 8^3 to 160^3 close to the critical point at zero magnetic field. We confirm explicitly the value of the critical coupling J_c found by Ballesteros et al. and estimate there the universal values of g_r and xi/L. At the critical point we study the finite size dependencies of the energy density

ZEUS Collaboration

Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range $10 < \Q2 < 10^4$ GeV$^2$ with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb$^{-1}$. The cross sections, measured in the Breit frame using the $\kt$ jet algorithm, are compared with next-to-leading-order perturbative QCD calculations usi

Naresh Dadhich, Sayan Kar, Sailajananda Mukherji, Matt Visser

A two-parameter family of spherically symmetric, static Lorentzian wormholes is obtained as the general solution of the equation $ρ=ρ_t=0$, where $ρ= T_{ij} u^iu^j$, $ρ_t = (T_{ij} - {1\over2} T g_{ij}) u^iu^j$, and $u^i u_i =- 1$. This equation characterizes a class of spacetimes which are ``self dual&#39;&#39; (in the sense of electrogravity duality). The