August 2000 arXiv papers — page 24

E. Buks, M. L. Roukes

We measure the adhesion energy of gold using a micromachined doubly-clamped beam. The stress and stiffness of the beam are characterized by measuring the spectrum of mechanical vibrations and the deflection due to an external force. To determine the adhesion energy we induce stiction between the beam and a nearby surface by capillary forces. Subsequent analy

V. Pascalutsa

The Rarita-Schwinger theory of free massive spin-3/2 field obeys the physical degrees of freedom counting, and one can distinguish ``consistent'' couplings which maintain this property and ``inconsistent'' couplings which destroy it. We show how one can obtain consistent couplings from inconsistent ones by a redefinition of the spin-3/2 field

Gernot Alber, Aldo Delgado, Nicolas Gisin, Igor Jex

A generalization of the quantum XOR-gate is presented which operates in arbitrary dimensional Hilbert spaces. Together with one-particle Fourier transforms this gate is capable of performing a variety of tasks which are important for quantum information processing in arbitrary dimensional Hilbert spaces. Among these tasks are the preparation of Bell states,

Bob Coecke, David Moore

We present a detailed synthetic overview of the utilisation of categorical techniques in the study of order structures together with their applications in operational quantum theory. First, after reviewing the notion of residuation and its implementation at the level of quantaloids we consider some standard universal constructions and the extension of adjunc

Bob Coecke, Isar Stubbe

We define a category with as objects operational resolutions and with as morphisms - not necessarily deterministic - state transitions. We study connections with closure spaces and join-complete lattices and sketch physical applications related to evolution and compoundness. An appendix with preliminaries on quantaloids is included.

Bob Coecke, Sonja Smets

We reconsider the description for property transitions due to perfect measurements, viewing them as a special case of general transitions that are due to an externally imposed change. We propose a corresponding syntax involving operational quantum logic and a fragment of non-commutative linear logic.

Gaston Garcia-Calderon, Jorge Villavicencio

Exact analytical solutions of the time-dependent Schrödinger equation with the initial condition of an incident cutoff wave are used to investigate the traversal time for tunneling. The probability density starts from a vanishing value along the tunneling and transmitted regions of the potential. At the barrier width it exhibits, at early times, a distributi

G. V. Stupakov

Interaction between the bunches in the NLC main linac via long range wakefields can cause a beam breakup instability. Although the magnitude of the long range wakefields for an ideal NLC structure is below the instability threshold, the wake increases when structure manufacturing errors are taken into account. In case of large errors, the developing instabil

G. V. Stupakov

We present a study of orbit jitter and emittance growth in a long linac caused by misalignment of quadrupoles. First, assuming a FODO lattice, we derive analytical formulae for the RMS deviation of the orbit and the emittance growth caused by random uncorrelated misalignments of all quadrupoles. We then consider an alignment algorithm based on minimization o

Giuseppe Giuliani

A general law for electromagnetic induction phenomena is derived from Lorentz force and Maxwell equation connecting electric field and time variation of magnetic field. The derivation provides with a unified mathematical treatment the statement according to which electromagnetic induction is the product of two independent phenomena: time variation of magneti

Rainer Wanzenberg

In the present design of the TESLA Linear Collider with integrated X-ray Laser Facility it is necessary that 1 ms long bunch trains with about 10000 bunches are generated and distributed to several free electron laser (FEL) beam lines. The different scientific applications of the X-ray FELs need specific filling patterns of the bunches in the bunch train. It

O. Teodorescu, A. K. Dutt-Mazumder, C. Gale

The effect of scalar and vector meson mixing on the dilepton radiation from hot and dense hadronic matter is estimated in different isospin channels. In particular, we study the effect of $\sigma$-$\omega$ and $\rho-a_0$ mixing and calculate the corresponding rates. Effects are found to be significant compared to standard $\pi$-$\pi$ and $K$-${\bar K}$ annih

Yoshifumi R. Shimizu, Kenichi Matsuyanagi

Diabatic description of rotational bands provides a clear-cut picture for understanding the back-bending phenomena, where the internal structure of the yrast band changes dramatically as a function of angular momentum. A microscopic framework to obtain the diabatic bands within the mean-field approximation is presented by making use of the selfconsistent col

L. Chkhaidze, T. Djobava, L. Kharkhelauri

The transverse momentum technique is used to analyse charged-particle exclusive data in central C-Ne and C-Cu interactions at energy of 3.7 GeV per nucleon. Clear evidence of in-plane and out-of-plane (squeeze-out) flow effects for protons and pi^{-} mesons have been obtained. In C-Ne interactions in-plane flow of pi^{-} mesons is in the same direction as fo

Yuri S. Kivshar, Andrey A. Sukhorukov

We present a brief overview of the basic concepts of the soliton stability theory and discuss some characteristic examples of the instability-induced soliton dynamics, in application to spatial optical solitons described by the NLS-type nonlinear models and their generalizations. In particular, we demonstrate that the soliton internal modes are responsible f

Vladimir Gol'dshtein, Alexander G. Ramm

New classes of non-smooth bounded domains D, for which the embedding operator from H^1(D) into L^2(D) is compact are introduced. Examples are given and applications to scattering by rough obstacles are mentioned.

Alexander G. Ramm

A review of the author's results is given. Inversion formulas and stability estimates for the solutions to 3D inverse scattering problems with fixed-energy data are obtained. Inversions of exact and noisy data are stidied. The inverse potential scattering problem is discussed in detail, inversion formulas are derived and error estimates are obtained. Inv

Vladimir Dragovic

A relationship between two old mathematical subjects is observed: the theory of hypergeometric functions and the separability in classical mechanics. Separable potential perturbations of the integrable billiard systems and the Jacobi problem for geodesics on an ellipsoid are expressed through the Appell hypergeometric functions $F_4$ of two variables. Even w

Edward Goldstein

In this paper we investigate the geometry of Calibrated submanifolds and study relations between their moduli-space and geometry of the ambient manifold. In particular for a Calabi-Yau manifold we define Special Lagrangian submanifolds for any Kahler metric on it. We show that for a choice of Kahler metric the Borcea-Voisin threefold has a fibration structur

C. C. Briggs

An enumeration is given of certain equivalence classes of directed multigraphs having 0 to 5 nodes with each node having 2 incoming and 2 outgoing arcs.

Jim Bryan

In his paper "Hodge integrals and degenerate contributions", Pandharipande studied the relationship between the enumerative geometry of certain 3-folds and the Gromov-Witten invariants. In some good cases, enumerative invariants (which are manifestly integers) can be expressed as a rational combination of Gromov-Witten invariants. Pandharipande specu

Geanina Tudose

We give a combinatorial description of sl(n)-fusion coefficients in the case where one partition has at most two columns and establih other properties for this case.

H. Alexander, John Wermer

The intersection index at a common point of two analytic varieties of complementary dimensions in $\Bbb C^n$ is positive. This observation, which has been called a ``cornerstone'' of algebraic geometry ([GH, p.~62]), is a simple consequence of the fact that analytic varieties carry a natural orientation. Recast in terms of linking numbers, it is our

Edward G. Effros, Marius Junge, Zhong-Jin Ruan

The operator space analogue of the {\em strong form} of the principle of local reflexivity is shown to hold for any von Neumann algebra predual, and thus for any $C^{*}$-algebraic dual. This is in striking contrast to the situation for $C^{*}$-algebras, since, for example, $K(H)$ does not have that property. The proof uses the Kaplansky density theorem toget

J. Marshall Ash, Gang Wang

We prove that if a multiple trigonometric series is spherically Abel summable everywhere to an everywhere finite function $f(x)$ which is bounded below by an integrable function, then the series is the Fourier series of $f(x)$ if the coefficients of the multiple trigonometric series satisfy a mild growth condition. As a consequence, we show that if a multipl

S. Gersten, T. Riley

Filling length measures the length of the contracting closed loops in a null-homotopy. The filling length function of Gromov for a finitely presented group measures the filling length as a function of length of edge-loops in the Cayley 2-complex. We give a bound on the filling length function in terms of the log of an isoperimetric function multiplied by a (

Hitoshi Murakami

I follow Y. Yokota to explain how to obtain a tetrahedron decomposition of the complement of a hyperbolic knot and compare it with the asymptotic behavior of Kashaev's link invariant using the figure-eight knot as an example.

T. Sasaki, M. Yoshida

The relation between the uniformizing equation of the complex hyperbolic structure on the moduli space of marked cubic surfaces and an Appell-Lauricella hypergeometric system in nine variables is clarified.

K. Matsumoto

Let $ψ$ be the period map for a family of the cyclic triple coverings of the complex projective line branching at six points. The symmetric group $S_6$ acts on this family and on its image under $ψ.$ In this paper, we give an $S_6$-equivariant expression of $ψ^{-1}$ in terms of fifteen theta constants.

K. Matsumoto, T. Terasoma

For a cubic surface X, by considering the intermediate Jacobian J(Y) of the triple covering Y of the 3-dimensional projective space branching along X, Allcock, Carlson and Toledo constructed a period map per from the family of marked cubic surfaces to the four dimensional complex ball embedded in the Siegel upper half space of degree 5. We give an expression

Gary McCartor

In this paper I shall discuss the way in which vacuum structure and condensates occur in the light-cone representation. I shall particularly emphasize the mechanism by which the mass squared of a composite such as the pion comes to depend linearly on the bare mass of its Fermion constituents. I shall give details in two dimensions then discuss the case of fo

Dmitri Diakonov, Victor Petrov

We recall the non-Abelian Stokes theorem for the Wilson loop in the Yang-Mills theory and discuss its meaning. Then we move to `gravitational Wilson loops', i.e. to holonomies in curved d=2,3,4 spaces and derive non-Abelian Stokes theorems for these quantities as well, which are similar to our formula in the Yang-Mills theory. In particular we derive an

B. Kleihaus, J. Kunz

We construct static axially symmetric black holes in SU(2) Einstein-Yang-Mills-Higgs theory. Located in between a monopole-antimonopole pair, these black holes possess magnetic dipole hair. The difference of their mass and their horizon mass equals the mass of the regular monopole-antimonopole solution, as expected from the isolated horizon framework.

R. L. Jaffe

I discuss two topics of current interest in the study of the spin structure of the nucleon. First, I discuss whether there is a sum rule for the components of the nucleon's angular moments. Second, I discuss the measurement of the nucleon's transversity distribution in light of recent results reported by the HERMES collaboration at DESY.

Thomas G. Rizzo

The complementarity of $e^+e^-$ and $γγ$ colliders to discover and explore new physics beyond the Standard Model(SM) is discussed. After briefly surveying a number of various new physics scenarios we concentrate in detail on signatures for Large Extra Dimensions via the process $γγ\to WW$.

A. C. Aguilar, A. A. Natale, R. Rosenfeld

We determine the critical coupling constant above which dynamical chiral symmetry breaking occurs in a class of QCD motivated models where the gluon propagator has an enhanced infrared behavior. Using methods of bifurcation theory we find that the critical value of the coupling constant is always smaller than the one obtained for QCD.

V. M. Mostepanenko, M. Novello

The recent ideas that the gravitational and gauge interactions become united at the weak scale lead to Yukawa-type corrections to the Newtonian gravitational law at small distances. We briefly summarize the best constraints on these corrections obtained recently from the experiments on the measurement of the Casimir force. The new constraints on the Yukawa-t

J. Nieves, E. Ruiz Arriola

Heavy Baryon Chiral Perturbation Theory (HBChPT) to leading order provides a kernel to solve the Bethe-Salpeter equation for the $P_{33}$ ($Δ(1232)$-channel) $π-N$ system, in the infinite nucleon mass limit. Crossed Born terms include, when iterated within the Bethe-Salpeter equation, both {\it all} one- and {\it some} two-pion intermediate states, hence pre

M. Roth

The complete O(alpha) electroweak radiative corrections to e+e- --> WW --> 4f in the electroweak Standard Model are presented in the double-pole approximation. We give analytical and numerical results for the non-factorizable corrections and express the factorizable virtual corrections in terms of the known corrections to on-shell W-pair production and W dec

Vladimir Ammosov, Guennadi Volkov

We conjecture that the topological structure of the gauge symmetries required by the Calabi-Yau vacuum and the dualities in string/D-branes considered in the world with some additional dimensions can lead to an extension of the main principles of the Special Theory of Relativity. The link between the topological structure of the vacuum and the, hierarchy of

David E. Miller

We consider various special cases of gluon condensates at finite temperature. The gluon condensate for an ideal gas of gluons with a given vacuum expectation value is introduced for the sake of comparison with that calculated using the recent finite temperature lattice gauge simulations for a pure Yang-Mills SU(3) gauge theory at the known critical temperatu

Fabio Siringo

The possible existence of Higgs-Higgs bound states in the Higgs sector of the Standard Model is explored using the |hh>+|hhh> variational ansatz of Di Leo and Darewych. The resulting integral equations can be decoupled exactly, yielding a one-dimensional integral equation, solved numerically. We thereby avoid the extra approximations employed by Di Leo and D

O-Kab Kwon, Choonkyu Lee, Hyunsoo Min

For the one-loop contribution to the QCD vacuum tunneling amplitude by quarks of generic mass value, we make use of a calculational scheme exploiting a large mass expansion together with a small mass expansion. The large mass expansion for the effective action is given by a series involving higher-order Seeley-DeWitt coefficients, and we carry this expansion

Jens O. Andersen

The conventional weak-coupling expansion for the pressure of a hot plasma shows no sign of convergence unless the the coupling constant $g$ is tiny. In this talk, I discuss screened perturbation theory (SPT) which is a reorganization of the perturbative expansion by adding and subtracting a local mass term in the Lagrangian. We consider several different mas

Sh. Matsumoto, M. Yoshimura

Time evolution of tunneling phenomena in medium is studied using a standard model of environment interaction. A semiclassical formula valid at low, but finite temperatures is derived in the form of integral transform for the reduced Wigner function, and the tunneling probability in thermal medium is calculated for a general tunneling potential of one dimensi

K. Kimura, A. Takamura

Within the framework of three generations of leptons the schematical method for estimating CP asymmetry in neutrino oscillations is considered. We introduce a unitarity triangle corresponding to ν_e-ν_μ oscillation, in addition, we show that it is convenient for the estimation to define another new triangle. CP asymmetry is determined by the difference betwe

Biswajoy Brahmachari

We construct a scalar potential of supersymmetric left-right model in the limit when supersymmetry is valid.

TARO Collaboration, Ph. de Forcrand, M. Garcia Perez, T. Hashimoto

We analyze temporal and spatial meson correlators in quenched lattice QCD at T>0. Below T_c we observe little change in the meson properties as compared with T=0. Above T_c we observe new features: chiral symmetry restoration and signals of plasma formation, but also indication of persisting mesonic (metastable) states and different temporal and spatial mass

Dmitri Diakonov, Victor Petrov

We present the non-Abelian Stokes theorem for the Wilson loop in various forms and discuss its meaning. Its validity has been recently questioned by Faber, Ivanov, Troitskaya and Zach. We demonstrate that all points of their criticism are based on mistakes in mathematics. Finally, we derive a variant of our formula for the Wilson loop in lattice regularizati

K. Rabbertz, U. Wollmer

Deep-inelastic ep scattering data, taken with the H1 and ZEUS detectors at HERA, are used to study the means and distributions of the event shape variables thrust, jet broadening, jet mass, C-parameter and two kinds of differential two-jet rate. The data cover a range of the four-momentum transfer Q, taken to be the relevant energy scale, between 7 GeV and 1

ALEPH Collaboration

The data collected at centre-of-mass energies of 188.6 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 176.2 pb-1, are analysed in a search for pair-produced charged Higgs bosons H+/-. Three analyses are employed to select the taunutaunu, taunucs and cscs final states. No evidence for a signal is found. Upper limits are set on the productio

ALEPH Collaboration

A serach for gamma gamma decays of Higgs boson is performed in the data sample collected at LEP with the ALEPH detector between 1991 and 1999. This corresponds to an integrated luminosity of 672 pb-1 centre-of-mass energies ranging from 88 to 202 GeV. The search is based on topologies arising from a Higgs boson produced in association with a fermion pair via

C. C. Briggs

This paper presents some possible features of general expressions for Lovelock tensors and for the coefficients of Lovelock Lagrangians up to the 15th order in curvature (and beyond) in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection.

Carlos Barcelo, Matt Visser

Taking the Randall-Sundrum models as background scenario, we derive generalized Israel-Lanczos-Sen thin-shell junction conditions for systems in which several bulk scalar fields are non-minimally coupled to gravity. We demonstrate that the form of the junction conditions (though arguably not the physics) depends on the choice of frame. We show that generally

A. Gorlitz, A. P. Chikkatur, W. Ketterle

Quantum degeneracy modifies light scattering and spontaneous emission. For fermions, Pauli blocking leads to a suppression of both processes. In contrast, in a weakly interacting Bose-Einstein condensate, we find spontaneous emission to be enhanced, while light scattering is suppressed. This difference is attributed to many-body effects and quantum interfere

Andrei Lopatin, Antoine Georges, T. Giamarchi

We consider the Hall effect in a system of weakly coupled Luttinger chains. We obtain the full conductivity tensor in the absence of dissipation along the chains. We show that while the dependence of the Hall and transverse conductivities on temperature and frequency are affected by the Luttinger interaction very strongly, the Hall resistivity is given by a

Reka Albert, Hawoong Jeong, Albert-Laszlo Barabasi

Many complex systems, such as communication networks, display a surprising degree of robustness: while key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these complex systems is often attributed to the redundant wiring of the functional web defined by the s

B. Bernu, Ladir Candido, D. M. Ceperley

Using Path Integral Monte Carlo we have calculated exchange frequencies as electrons undergo ring exchanges in a ``clean'' 2d Wigner crystal as a function of density. The results show agreement with WKB calculations at very low density, but show a more rapid increase with density near melting. Remarkably, the exchange Hamiltonian closely resembles th

B. Giovannini, C. Berthod

A theory of superconductivity based on the two-body Cooperon propagator is presented. This theory takes the form of a modified Gorkov equation for the Green's function and allows one to model the effect of local superconducting correlations and long range phase fluctuations on the spectral properties of high temperature superconductors, both above and be

Ulrich Hohenester, Giovanna Panzarini, Filippo Troiani, Elisa Molinari

We propose a solid-state implementation of stimulated Raman adiabatic passage in two coupled semiconductor quantum dots. Proper combination of two pulsed laser fields allows the coherent carrier transfer between the two nanostructures without suffering significant losses due to environment coupling. By use of a general solution scheme for the carrier states

I. K. Yanson, V. V. Fisun, J. A. Mydosh, J. M. van Ruitenbeek

Point-contact spectroscopy is applied to study the energy dependence of paramagnetic impurities in noble metals. The samples are in the form of the so-called "mechanically controllable break-junctions" where the investigated piece of alloy makes a nanowire connecting two bulk electrodes.The lateral dimensions of the bridge are of the order of a few n

J. L. de Boer, G. Maris, A. Meetsma, J. Baas

This response on a Comment on Reference 2 discusses the space group Fmm2 determination of the low temperature structure of NaV2O5. We show that while conventional crystallography is consistent with 'zig-zag' charge ordering of half of the ladders, recent spectroscopic measurements suggest that the symmetry is lower than Fmm2. We suggest space group C

Benny Davidovitch, Anders Levermann, Itamar Procaccia

Diffusion Limited Aggregation (DLA) is a model of fractal growth that had attained a paradigmatic status due to its simplicity and its underlying role for a variety of pattern forming processes. We present a convergent calculation of the fractal dimension D of DLA based on a renormalization scheme for the first Laurent coefficient of the conformal map from t

N. S. Skantzos, A. C. C. Coolen

We extend a recently introduced class of exactly solvable models for recurrent neural networks with competition between 1D nearest neighbour and infinite range information processing. We increase the potential for further frustration and competition in these models, as well as their biological relevance, by adding next-nearest neighbour couplings, and we all

Roelof S. de Jong, Cedric Lacey

We investigate the dependence of the local space density of spiral galaxies on luminosity, scalesize and surface brightness. We derive bivariate space density distributions in these quantities from a sample of about 1000 Sb-Sdm spiral galaxies, corrected for selection effects in luminosity and surface brightness. The structural parameters of the galaxies wer

Graca Rocha, Joao Magueijo, Mike Hobson, Anthony Lasenby

We propose a rigorous, non-perturbative, Bayesian framework which enables one jointly to test Gaussianity and estimate the power spectrum of CMB anisotropies. It makes use of the Hilbert space of an harmonic oscillator to set up an exact likelihood function, dependent on the power spectrum and on a set of parameters $α_i$, which are zero for Gaussian process

Daniel J. Mortlock, Rachel L. Webster, Paul J. Francis

Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a population of objects that have not yet been successfully classified. Building on the arguments of Kochanek, Falco & Munoz (1999), it is shown that there are no objectiv

J. P. Willis, P. C. Hewett, S. J. Warren, G. F. Lewis

We present a spectroscopic survey for strong galaxy-galaxy lenses. Exploiting optimal sight-lines to massive, bulge-dominated galaxies at redshifts $z \sim 0.4$ with wide-field, multifibre spectroscopy, we anticipate the detection of 10-20 lensed Lyman-$α$ emitting galaxies at redshifts $z \simgreat 3$ from a sample of 2000 deflectors. Initial spectroscopic

Steve Rawlings

I review some recent cosmological studies based on redshift surveys of radio sources selected at low frequencies. The accretion rate onto the central black hole is identified as the basis of a crude physical division of the low-frequency population into two sub-populations: the first comprises `Eddington-tuned' (high accretion rate) quasars and their tor

K. J. Borkowski, W. J. Lyerly, S. P. Reynolds

Improved calculations of X-ray spectra for supernova remnants (SNRs) in the Sedov-Taylor phase are reported, which for the first time include reliable atomic data for Fe L-shell lines. This new set of Sedov models also allows for a partial collisionless heating of electrons at the blast wave and for energy transfer from ions to electrons through Coulomb coll

A. Efstathiou, S. Oliver, M. Rowan-Robinson, C. Surace

We present results and source counts at 90micron extracted from the Preliminary Analysis of the European Large Area ISO Survey (ELAIS). The survey covered about 11.6 square degrees of the sky in four main areas and was carried out with the PHOT instrument onboard the Infrared Space Observatory (ISO). The survey is at least an order of magnitude deeper than t

Martin Elvis

This paper proposes a simple, empirically derived, unifying structure for the inner regions of quasars. This structure is constructed to explain the broad absorption line (BAL) regions, the narrow `associated' ultraviolet and X-ray warm absorbers (NALs); and is also found to explain the broad emission line regions (BELR), and several scattering features,

P. L. Biermann, E. -J. Ahn, G. Medina Tanco, T. Stanev

Introducing a simple Galactic wind model patterned after the solar wind we show that back-tracing the orbits of the highest energy cosmic events suggests that they may all come from the Virgo cluster, and so probably from the active radio galaxy M87. This confirms a long standing expectation. Those powerful radio galaxies that have their relativistic jets st

P. Battinelli, S. Demers

We present the latest results of our ongoing four filter photometric survey of C stars in Local Group dwarf irregular galaxies. Observations of the two low luminosity dwarf irregular galaxies, Pegasus and DDO 210, revealed respectively 40 and 3 C stars, assuming that the reddening of Pegasus is negligible. No C stars were identified in Tucana. Our observatio

Pier Luigi Selvelli, Piercarlo Bonifacio

We present here the first results of UVES observations of RR Tel. The exceptional performances of the instrument have allowed the detection of new spectral features and have led to an improvement in the identifications of several emission lines. A direct comparison with the IUE observations in the range 3045-3300 A has revealed the appearance of many weak an

T. Tsuji

We report a detection of water in emission in the spectrum of the M2 supergiant atar mu Cep (M2Ia) observed by the Short Wavelength Spectrometer (SWS) aboard Infrared Space Observatory (ISO) and now released as the ISO Archives. The emission first appears in the 6 micron region (nu2 fundamental) and then in the 40 micron region (pure rotation lines) despite

A. V. Filippenko, A. G. Riess

We review the use of Type Ia supernovae for cosmological distance determinations. Low-redshift SNe Ia (z < 0.1) demonstrate that the Hubble expansion is linear, that H_0 = 65 +/- 2 (statistical) km/s/Mpc, and that the properties of dust in other galaxies are similar to those of dust in the Milky Way. We find that the light curves of high-redshift (z = 0.3-1)

Roelof S. de Jong, Eric F. Bell

We use spiral galaxy evolution models to argue that there are substantial variations in stellar mass-to-light ratio (M/L) within and among galaxies. Our models show a strong correlation between stellar M/L and galaxy color. We compare the colors and maximum-disk M/L values of a sample of galaxies to the model color-M/L relation, finding that a Salpeter IMF i

Charles R. Cowley

As soon as Lyman or Balmer lines overlap, the net absorption cross section rapidly approaches the value at the series limit. Independent of the difficult question of the relative contributions of line and continuous opacity, we can get a good estimate of their sum.

H. J. Rocha-Pinto, John Scalo, W. J. Maciel, Chris Flynn

A chromospheric age distribution of 552 late-type dwarfs is transformed into a star formation history by the application of scale height corrections, stellar evolutionary corrections and volume corrections. We show that the disk of our Galaxy has experienced enhanced episodes of star formation at 0-1 Gyr, 2-5 Gyr and 7-9 Gyr ago, although the reality of the

H. J. Rocha-Pinto, W. J. Maciel, John Scalo, Chris Flynn

The age-metallicity relation of the solar neighbourhood is studied using a sample of 552 late-type dwarfs. This sample was built from the intersection of photometric catalogues with chromospheric activity surveys of the Mount Wilson group. For these stars, metallicities were estimated from uvby data, and ages were calculated from their chromospheric emission

Aaron Bergman, Ori J. Ganor

T-duality of gauge theories on a noncommutative $T^d$ can be extended to include fields with twisted boundary conditions. The resulting T-dual theories contain novel nonlocal fields. These fields represent dipoles of constant magnitude. Several unique properties of field theories on noncommutative spaces have simpler counterparts in the dipole-theories.

Onuttom Narayan, A. P. Young

We give two direct, elementary proofs that a Monte Carlo simulation converges to equilibrium provided that appropriate conditions are satisfied. The first proof requires detailed balance while the second is quite general.

V. P. Nair

We consider the quantum mechanics of a particle on a noncommutative two-sphere with the coordinates obeying an SU(2)-algebra. The momentum operator can be constructed in terms of an $SU(2)\times SU(2)$-extension and the Heisenberg algebra recovered in the smooth manifold limit. Similar considerations apply to the more general SU(n) case.

David Neuffer

A muon storage ring neutrino source uses an induction linac for muon capture, a 200 MHz copper cavity system for cooling, and 200 and 400 MHz superconducting rf systems for acceleration to a final energy of up to 50 GeV. These systems and their requirements are discussed in this paper.

M. W. Bautz, M. R. Malm, F. K. Baganoff, G. R. Ricker

We report the detection by Chandra of SMM J02399-0134 and SMM J02399-0136, two distant (z=1.06 and z=2.81, respectively) submillimeter sources gravitationally magnified by the galaxy cluster Abell 370. These are high-significance (> 7-sigma) X-ray detections of the high-redshift submillimeter source population. The X-ray positions are coincident with the opt

P. M. Garnavich, A. Loeb, K. Z. Stanek

The afterglow of the Gamma-Ray Burst (GRB) 000301C exhibited achromatic, short time-scale variability that is difficult to reconcile with the standard relativistic shock model. We interpret the observed light curves as a microlensing event superimposed on power-law flux decays typical of afterglows. In general, a relativistic GRB shock appears on the sky as

Lexie Davison, David Sherrington

In this article we study a simple, purely topological, cellular model which is allowed to evolve through a Glauber-Kawasaki process. We find a non-thermodynamic transition to a glassy phase in which the energy (defined as the square of the local cell topological charge) fails to reach the equilibrium value below a characteristic temperature which is dependen

Konstadinos Sfetsos

It was recently proposed that there exist stable supersymmetric phases for finite temperature superstings. This issue was investigated using an effective supergravity which takes into account massive winding modes. Such a theory admits BPS solutions that do not suffer from Hagedorn-type instabilities. We extend several aspects of this work. First we restrict

A. Bodek, U. K. Yang, T. Adams, A. Alton

We report on the extraction of the structure functions F_2 and Delta xF_3 = xF_3nu-xF_3nubar from CCFR neutrino-Fe and antineutrino-Fe differential cross sections. The extraction is performed in a physics model independent (PMI) way. This first measurement for Delta xF_3, which is useful in testing models of heavy charm production, is higher than current the

A. Mikovic, R. Picken

We study the moduli space of a super Chern-Simons theory on a manifold with the topology ${\bf R}\times §$, where $§$ is a compact surface. The moduli space is that of flat super connections modulo gauge transformations on $§$, and we study in detail the case when $§$ is atorus and the supergroup is $OSp(m|2n)$. The bosonic moduli space is determined by the

Zhi-zhong Xing

We argue that a small or large CP-violating asymmetry {\cal A}_{ψK_S} in B^0_d vs \bar{B}^0_d --> J/ψK_S decays, which seems to be favored by the recent BaBar or Belle data, might hint at the existence of new physics in B^0_d - \bar{B}^0_d mixing. We present a model-independent framework to show how new physics in B^0_d - \bar{B}^0_d mixing modifies the stan

M. Latapy

In this paper, we study two kinds of combinatorial objects, generalized integer partitions and tilings of two dimensional zonotopes, using dynamical systems and order theory. We show that the sets of partitions ordered with a simple dynamics, have the distributive lattice structure. Likewise, we show that the set of tilings of zonotopes, ordered with a simpl

Matthieu Latapy, Thi Ha Duong Phan

In this paper, we use a simple discrete dynamical model to study integer partitions and their lattice. The set of reachable configurations of the model, with the order induced by the transition rule defined on it, is the lattice of all partitions of an integer, equipped with a dominance ordering. We first explain how this lattice can be constructed by an alg

Yasuaki Hikida, Masatoshi Nozaki, Tadashi Takayanagi

We study a brane-antibrane system and a non-BPS D-brane in SU(2) WZW model. We first discuss the tachyon condensation using the vertex operator formalism and find the generation of codimension two D-branes after the condensation. Our result is consistent with the recent interpretation that a D2-brane is a bound state of D0-branes. Then we investigate the wor

A. S. Moskvin, Yu. D. Panov

Specific d-wave angular dependence of the in-plane magnetoresistence in antiferromagnetic tetragonal YBa_{2}Cu_{3}O_{6+x} (x~0.3) on orientation of the external magnetic field in (a,b) plane is assigned to the effective hole transport through low lying excited purely oxygen doublet O2pe_u state, not the ground b_{1g}(d_{x^2-y^2}) state. External magnetic fie

M. Baldicchi, G. M. Prosperi

We compute the c \bar{b} spectrum from a first principle Salpeter equation obtained in a preceding paper. For comparison we report also the heavy-light quarkonium spectrum and the hyperfine separations previously presented only in a graphical form. Notice that all results are parameter free.

Mark Gross, P. M. H. Wilson

Motivated by the picture of mirror symmetry suggested by Strominger, Yau and Zaslow, we made a conjecture concerning the Gromov-Hausdorff limits of Calabi-Yau n-folds (with Ricci-flat Kähler metric) as one approaches a large complex structure limit point in moduli; a similar conjecture was made independently by Kontsevich, Soibelman and Todorov. Roughly stat

M. Amenomori, S. Ayabe, Caidong

Since 1996, a hybrid experiment consisting of an emulsion chamber and a burst detector array and the Tibet-II air shower array has been operated at Yangbajing (4300 m above sea level) in Tibet. This experiment can detect air-shower cores, called burst events, accompanied by air showers in excess of about 100 TeV. Using the burst event data observed by this e

Davoud Kamani

In this paper we consider the worldsheet of superstring as a noncommutative space. Some additional terms can be added to the superstring action, such that for ordinary worldsheet they are zero. Expansion of this extended action up to the first order of the noncommutativity parameter, leads to the new supersymmetric action for string. For the closed superstri