arXiv papers from February 2002

O. de la Pena, A. Aguayo, R. de Coss

We have studied the structural and electronic properties of Mg(1-x)Al(x)B2 within the Virtual Crystal Approximation (VCA) by means of first-principles total-energy calculations. Results for the lattice parameters, the electronic band structure, and the Fermi surface as a function of Al doping for 0<x<0.6 are presented. The ab initio VCA calculations are in e

Weiqiang Wang

The Jucys-Murphy elements for wreath products G_n associated to any finite group G are introduced and they play an important role in our study on the connections between class algebras of G_n for all n and vertex algebras. We construct an action of (a variant of) the W_{1+\infty} algebra acting irreducibly on the direct sum R_G of the class algebras of G_n f

Pavel Etingof, Adriano Moura

We study a quantum version of the Kazhdan-Lusztig functor. Namely, we prove that there exists a fully faithfull exact tensor functor from the category of finite dimensional representations of the quantum affine algebra Uq(sl(n)) (with extended scalars) to the category of finite dimensional representations of Felder's elliptic quantum group E_{\tau,\gamma2}(g

Shaffique Adam, Piet W. Brouwer, James P. Sethna, Xavier Waintal

In random-matrix ensembles that interpolate between the three basic ensembles (orthogonal, unitary, and symplectic), there exist correlations between elements of the same eigenvector and between different eigenvectors. We study such correlations, using a remarkable correspondence between the interpolating ensembles late in the crossover and a basic ensemble

A. M. Ghezelbash, R. B. Mann

We investigate vortex solutions to the Abelian Higgs field equations in a four dimensional de Sitter spacetime background. We obtain both static and dynamic solutions with axial symmetry that are generalizations of the Nielsen-Olesen gauge vortices in flat spacetime. The static solution is located in the static patch of de Sitter space. We numerically solve

Alexander Kusenko

Future detectors of cosmic rays, such as EUSO and OWL, can test the Standard Model predictions for the neutrino interactions at energies well beyond the reach of any terrestrial experiment. The relative rates of horizontal and upgoing air showers, combined with the angular distribution of upgoing air showers will allow one to measure the neutrino-nucleon cro

Alfredo Herrera-Aguilar, Oleg V. Kechkin

We present a new approach for generation of solutions in the four-dimensional heterotic string theory with one vector field and in the five-dimensional bosonic string theory starting from the static Einstein-Maxwell fields. Our approach allows one to construct the solution classes invariant with respect to the total subgroup of the three-dimensional charging

Jack Allen, Housila P. Singh, Sarjinder Singh, Florentin Smarandache

In this paper we have suggested two classes of estimators for population median M_Y of the study character Y using information on two auxiliary characters X and Z in double sampling. It has been shown that the suggested classes of estimators are more efficient than the one suggested by Singh et al (2001). Estimators based on estimated optimum values have bee

Alfredo Herrera-Aguilar, Oleg V. Kechkin

We present a new approach for generating solutions in heterotic string theory compactified down to three dimensions on a torus with d+n>2, where d and n stand for the number of compactified space--time dimensions and Abelian gauge fields, respectively. It is shown that in the case when d=2k+1 and n is arbitrary, one can apply a solution--generating procedure

Michael Gutperle, Andrew Strominger

Scalar field theories with appropriate potentials in Minkowski space can have time-dependent classical solutions containing topological defects which correspond to S-branes - i.e. branes all of whose tangential dimensions are spacelike. It is argued that such S-branes arise in string theory as time-dependent solutions of the worldvolume tachyon field of an u

Volker Runde

Let $A$ be a Banach algebra. The flip on $A \otimes A^\op$ is defined through $A \otimes A^\op \ni a \tensor b \mapsto b \tensor a$. If $A$ is ultraprime, $\El(A)$, the algebra of all elementary operators on $A$, can be algebraically identified with $A \otimes A^\op$, so that the flip is well defined on $\El(\A)$. We show that the flip on $\El(A)$ is discont

P. Zinn-Justin

The expression of the large $N$ Harish Chandra--Itzykson--Zuber (HCIZ) integral in terms of the moments of the two matrices is investigated using an auxiliary unitary two-matrix model, the associated biorthogonal polynomials and integrable hierarchy. We find that the large $N$ HCIZ integral is governed by the dispersionless Toda lattice hierarchy and derive

Rachid Choukri, El Hossein Illoussamen, Volker Runde

Let $A$ be a Banach algebra. We call a pair $(G, B)$ a Gelfand theory for $A$ if the following axioms are satisfied: (G 1) $B$ is a $C^\ast$-algebra, and $G : A \to B$ is a homomorphism; (G 2) the assignment $L \mapsto G^{-1}(L)$ is a bijection between the sets of maximal modularleft ideals of $B$ and $A$, respectively; (G 3) for each maximal modular left id

Pablo Laguna, Deirdre Shoemaker

There is strong evidence indicating that the particular form used to recast the Einstein equation as a 3+1 set of evolution equations has a fundamental impact on the stability properties of numerical evolutions involving black holes and/or neutron stars. Presently, the longest lived evolutions have been obtained using a parametrized hyperbolic system develop

Volker Runde

We give an example of an amenable, radical Banach algebra, relying on results from non-abelian harmonic analysis due to H. Leptin, D. Poguntke and J. Boidol.

Yu. G. Gurevich, G. N. Logvinov, A. F. Carballo-Sanchez, Yu. V. Drogobitskiy

Electron and phonon transient temperatures are analyzed in the case of nondegenerate semiconductors. An analytical solution is obtained for rectangular laser pulse absorption. It is shown that thermal diffusion is the main energy relaxation mechanism in the phonon subsystem. The mechanism depends on the correlation between the sample length and the electron

Yu. G. Gurevich, G. N. Logvinov, N. Munoz-Aguirre, L. Martinez-Perez

The dependence on chopper frequency of the effective thermal diffusivity and effective thermal conductivity in photoacoustic experiments is discussed. The theoretical model of a two-layer structure at rear-surface illumination in the high frequency limit is considered. It is shown that the effective thermal diffusivity presents ``resonance'' while the effect

Eric L. Sandquist, Jon J. Dokter, D. N. C. Lin, Rosemary A. Mardling

We examine the overall likelihood that the consumption of a giant planet could pollute its host star. First, we show that the detection of 6Li in SWPs could be used to distinguish between giant planet formation theories, and can be used to detect the consumption of giant planets independent of planet mass. Second, we examine the probability that giant planet

D. S. Kuzmenko, Yu. A. Simonov

Gauge invariant extended configurations are considered for the three fundamental (quarks) or adjoint (gluons) particles. For quarks it is shown that the Y-shaped configuration is the only possible. For adjoint sources both the Y-shaped and triangular configurations may realize. The corresponding static potentials are calculated in the Method of Field Correla

A. Kirchner, D. Müller

We consider hard leptoproduction of a photon on a spin-one target and give the general azimuthal angular dependence of the differential cross section. Furthermore, we estimate the beam spin asymmetry for an unpolarized deuteron target at HERMES.

T. J. Davidge, S. Courteau

J, H, and K' images obtained with the Canada-France-Hawaii Telescope adaptive optics system are used to investigate the star-forming histories of the central regions of the Sc galaxies NGC 247 and NGC 2403. The brightest resolved red stars within 15 arcsec of the nucleus of each galaxy are red supergiants, indicating that the central few hundred parsecs of t

F. Buccella, C. A. Savoy

We study the supersymmetric spontaneous symmetry breaking of SO(10) into SU(3)xSU(2)xU(1) for the most physically interesting cases of SU(5) or flipped SU(5)xU(1) intermediate symmetries. The first case is more easily realized while the second one requires a fine-tuning condition on the parameters of the superpotential. This is because in the case of SU(5) s

A. B. Kuklov, B. V. Svistunov

Conservation of the total isotopic spin S of a two-component Bose gas-like $^{87}$Rb-has a dramatic impact on the structure of the ground state. In the case when S is much smaller than the total number of particles N, the condensation of each of the two components occurs into two single-particle modes. The quantum wavefunction of such a groundstate is a Schr

D. H. Coule

Penrose [1] has emphasized how the initial big bang singularity requires a special low entropy state. We address how recent brane cosmological schemes address this problem and whether they offer any apparent resolution. Pushing the start time back to $t=-\infty$ or utilizing maximally symmetric AdS spaces simply exacerbates or transfers the problem. Because

R. Ortega, D. d'Enterria, F. Fernandez, G. Martinez

We present the results of the analysis of the hard photon production in the $^{129}${Xe}+$^{\rm nat}${Sn} at 50{\it A} MeV system studied in the GANIL E300 experiment. The energy and angular hard photon distributions confirm the existence of a thermal component which follows the recently measured thermal bremsstrahlung systematics. Exploiting the performance

A. Asselah, F. Castell

We show the existence of non-trivial quasi-stationary measures for conservative attractive particle systems on $\ZZ^d$ conditioned on avoiding an increasing local set $\A$. Moreover, we exhibit a sequence of measures $\{\nu_n\}$, whose $\omega$-limit set consists of quasi-stationary measures. For zero range processes, with stationary measure $\nur$, we prove

Neeti Parashar

The \d0 (DZERO) Detector at Fermilab is currently collecting data since March 1, 2001, called Run 2. The detector has undergone an extensive upgrade to participate in the Run 2 data taking. The design of the detector meets the requirements of the high luminosity environment provided by the accelerator. This paper describes the upgraded detector subsystems an

Masud Chaichian, Dimitri Polyakov

By considering the B-field dynamical and studying its interaction with Ramond-Ramond (RR) background we observe the breaking of the B-field gauge symmetry in the effective action. This effect takes place due to non-perturbative coupling of the B-field to membrane topological charge. As a result, the B-field is renormalized in the RR backgrounds, making it im

Eugen Radu

In this paper we look for static, purely magnetic, nonabelian solutions with unusual topology in the context of N=4 Freedman-Schwarz supergravity in four dimensions.Two new exact solutions satisfying first order Bogomol'nyi equations are discussed.The main characteristics of the general solutions are presented and differences with respect to the spherically

Emilio Elizalde, Sergi R. Hildebrandt

We find the general solution for the spacetimes describing the interior of static black holes with an equation of state of the type $ T^0_0 = T^1_1 $ ($T$ being the stress-energy tensor). This form is the one expected from taking into account different quantum effects associated with strong gravitational fields. We recover all the particular examples found i

M. Bregant, G. Cantatore, F. Della Valle, G. Ruoso

We report on the frequency locking of a frequency doubled Nd:YAG laser to a 45 000 finesse, 87-cm-long, Fabry-Perot cavity using a modified form of the Pound-Drever-Hall technique. Necessary signals, such as light phase modulation and frequency correction feedback, are fed direcly to the infrared pump laser. This is sufficient to achieve a stable locking of

V. Batagelj, M. Zaveršnik

Cores are, besides connectivity components, one among few concepts that provides us with efficient decompositions of large graphs and networks. In the paper a generalization of the notion of core of a graph based on vertex property function is presented. It is shown that for the local monotone vertex property functions the corresponding cores can be determin

Z. Bern, A. De Freitas, L. Dixon, H. L. Wong

We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme and is designed to be compatible with the use of helicity states for "observed" particles. It is similar to dimensional

Ansgar Freking, Wolfgang Kinzel, Ido Kanter

Artificial neural networks which are trained on a time series are supposed to achieve two abilities: firstly to predict the series many time steps ahead and secondly to learn the rule which has produced the series. It is shown that prediction and learning are not necessarily related to each other. Chaotic sequences can be learned but not predicted while quas

P. M. Ostrovsky, M. A. Skvortsov, M. V. Feigel'man

Semiclassical theory of proximity effect predicts a gap E_g \sim hD/L^2 in the excitation spectrum of a long diffusive SNS junction. Mesoscopic fluctuations lead to anomalously localized states in the normal part of the junction. As a result, a non-zero, yet exponentially small, density of states appears at energies below E_g. In the framework of the superma

Subrata Pal, C. M. Ko, Zi-wei Lin

Within a multiphase transport model we study phi meson production in relativistic heavy ion collisions from both superposition of initial multiple proton-proton interactions and the secondary collisions in the produced hadronic matter. The yield of phi mesons is then reconstructed from their decaying product of either the kaon-antikaon pairs or the dimuon pa

Bobby Acharya, Mina Aganagic, Kentaro Hori, Cumrun Vafa

We consider orientifolds of Calabi-Yau 3-folds in the context of Type IIA and Type IIB superstrings. We show how mirror symmetry can be used to sum up worldsheet instanton contributions to the superpotential for Type IIA superstrings. The relevant worldsheets have the topology of the disc and ${\bf RP^2}$.

I. Wetzorke

Pseudo-scalar and vector meson correlation functions were calculated at temperatures below and above the deconfinement transition using ${\cal O}(a)$ improved Wilson fermions in quenched lattice QCD. The spectral functions were reconstructed from the correlator given only at discrete points in Euclidean time by means of the Maximum Entropy Method without a p

Z. Fodor, S. D. Katz, G. Papp

We study the feasibility of a PC-based parallel computer for medium to large scale lattice QCD simulations. The E\"otv\"os Univ., Inst. Theor. Phys. cluster consists of 137 Intel P4-1.7GHz nodes with 512 MB RDRAM. The 32-bit, single precision sustained performance for dynamical QCD without communication is 1510 Mflops/node with Wilson and 970 Mflops/node wit

Volker Runde

We give a popular account of the Banach-Tarski paradox and its connections with the axiom of choice.

R. Quian Quiroga, T. Kreuz, P. Grassberger

We propose a simple method to measure synchronization and time delay patterns between signals. It is based on the relative timings of events in the time series, defined e.g. as local maxima. The degree of synchronization is obtained from the number of quasi-simultaneous appearances of events, and the delay is calculated from the precedence of events in one s

Volker Runde

We give a short biographical sketch of Karl Weierstrass.

A. Grigoriev, A. Lobanov, A. Studenikin

The Lorentz invariant formalism for description of neutrino flavor oscillation in moving and polarized matter is developed. It is shown that the neutrino effective potential, which determines the effective mass difference between neutrinos in matter can be sufficiently changed by relativistic motion of matter. In the case of matter motion parallel to neutrin

Utpal Chattopadhyay, Achille Corsetti, Pran Nath

The theoretical status of the muon anomaly is reviewed including the recent change in the light by light hadronic correction. Specific attention is given to the implications of the shift in the difference between the BNL experimental result and the standard model prediction for sparticle mass limits. The implication of the BNL data for Yukawa unification is

Holger Gies

The effective average action of Yang-Mills theory is analyzed in the framework of exact renormalization group flow equations. Employing the background-field method and using a cutoff that is adjusted to the spectral flow, the running of the gauge coupling is obtained on all scales. In four dimensions and for the gauge groups SU(2) and SU(3), the coupling app

F. A. Grunbaum, I. Pacharoni, J. Tirao

We present a friendly introduction to the very detailed results in [9,10,11] and as an illustration we discuss here the issue of {\em linearization of products}. We find some interesting new phenomena.

J. D. Frankland, A. Chbihi, S. Hudan, A. Mignon

Fragment production in central collisions of Xe+Sn has been systematically studied with the INDRA multidetector from 25 to 150 AMeV. The predominant role of collision dynamics is evidenced in multiple intermediate mass fragment production even at the lowest energies, around the so-called "multifragmentation threshold". For beam energies 50 AMeV and above, a

Lawrence Ein, Robert Lazarsfeld, Karen E. Smith

In this paper we use the theory of multiplier ideals to show that the valuation ideals of a rank one Abhyankar valuation centered at a smooth point of a complex algebraic variety are approximated, in a quite strong sense, by sequences of powers of fixed ideals. Fix a rank one valuation v centered at a smooth point x on an algebraic variety over a field of ch

K. Vaninsky

The dynamics of finite nonperiodic Toda lattice is an isospectral deformation of the finite three--diagonal Jacobi matrix. It is known since the work of Stieltjes that such matrices are in one--to--one correspondence with their Weyl functions. These are rational functions mapping the upper half--plane into itself. We consider representations of the Weyl func

C. Bona, C. Palenzuela

New numerical methods have been applied in relativity to obtain a numerical evolution of Einstein equations much more robust and stable. Starting from 3+1 formalism and with the evolution equations written as a FOFCH (first-order flux conservative hyperbolic) system, advanced numerical methods from CFD (Computational Fluid Dynamics) have been successfully ap

Frank Ferrari

Recently, the author has proposed a generalization of the matrix and vector models approach to the theory of random surfaces and polymers. The idea is to replace the simple matrix or vector (path) integrals by gauge theory or non-linear sigma model (path) integrals. We explain how this solves one of the most fundamental limitation of the classic approach: we

O. J. Ganor, J. Sonnenschein

We study the strong coupling dynamics of the heterotic E_8 x E_8 string theory on the orbifolds T^6/Z_3 and C^3/Z_3 using the duality with the Horava-Witten M-theory picture. This leads us to a conjecture about the low energy description of the five dimensional E_0-theory (the CFT that describes the the singularity region of M-theory on C^3/Z_3) compactified

A. N. Pechen, I. V. Volovich

A notion of quantum multipole (in particular, dipole) noise is considered. Quantum dipole noise is an analogue of quantum white noise but it acts in a Fock space with indefinite metric. Quantum {\it white} noise describes the leading term in the stochastic limit approximation to quantum dynamics while quantum {\it multipole} noise describes the corrections t

UKQCD Collaboration, K. C. Bowler, G. Douglas, R. D. Kenway

The form factors for the semi-leptonic B->D and B->D* decays are evaluated in quenched lattice QCD at two different values of the coupling, beta=6.0 and 6.2. The action and the operators are fully O(a) non-perturbatively improved. The slope of the Isgur-Wise function is evaluated, and found to be rho^2=0.83^{+15+24}_{-11-1} (quoted errors are statistical and

A. Dobrzycki, P. J. Groot, L. M. Macri, K. Z. Stanek

We present the discovery of four X-ray quasars (z_em = 0.26, 0.53, 0.61, 1.63) located behind the Large Magellanic Cloud; three of them are located behind the bar of the LMC. The quasars were identified via spectroscopy of optical counterparts to X-ray sources found serendipitously by the Chandra X-ray Observatory satellite. All four quasars have archival VI

Iain Gordon

Symplectic reflection algebras arise in many different mathematical disciplines: integrable systems, Lie theory, representation theory, differential operators, symplectic geometry. In this paper, we introduce baby Verma modules for symplectic reflection algebras of complex reflection groups at parameter t=0 (the so--called rational Cherednik algebras at para

L. V. Toth, Cs. Kiss, M. Juvela, M. Stickel

A faint $I_{\rm 170}=4$ MJysr$^{-1}$ bipolar globule was discovered with the ISOPHOT 170 $\mu$m Serendipity Survey (ISOSS). ISOSS J 20246+6541 is a cold ($T_{\rm d}\approx 14.5$ K) FIR source without an IRAS pointsource counterpart. In the Digitized Sky Survey B band it is seen as a 3\arcmin size bipolar nebulosity with an average excess surface brightness o

S. L. Danilishin, F. Ya. Khalili

A new procedure of the linear position measurement which allows to obtain sensitivity better than the Standard Quantum Limit and close to the Energetic Quantum Limit is proposed and analyzed in details. Proposed method is based on the principles of stroboscopic quantum measurement and variation quantum measurement and allows to avoid main disadvantages of bo

S. Akamatsu, M. Plapp, G. Faivre, A. Karma

We demonstrate by both experiments and phase-field simulations that lamellar eutectic growth can be stable for a wide range of spacings below the point of minimum undercooling at low velocity, contrary to what is predicted by existing stability analyses. This overstabilization can be explained by relaxing Cahn's assumption that lamellae grow locally normal t

A. Covello, A. Gargano, N. Itaco

We investigate the role of the tensor force in the description of doubly odd deformed nuclei within the framework of the particle-rotor model. We study the rare-earth nuclei 174Lu, 180Ta, 182Ta, and 188Re using a finite-range interaction, with and without tensor terms. Attention is focused on the lowest K=0 and K=1 bands, where the effects of the residual ne

H. Nikolic

A new approach to the concept of particles and their production in quantum field theory is developed. A local operator describing the current of particle density is constructed for scalar and spinor fields in arbitrary gravitational and electromagnetic backgrounds. This enables one to describe particles in a local, general-covariant and gauge-invariant way.

F. T. Brandt, J. Frenkel, D. G. C. McKeon

We study the behaviour of the two- and three-point thermal Green functions, to one loop order in noncommutative U(N) Yang-Mills theory, at temperatures $T$ much higher than the external momenta $p$. We evaluate the amplitudes for small and large values of the variable $\theta p T$ ($\theta$ is the noncommutative parameter) and exactly compute the static gluo

C. M. Gutierrez, M. Lopez-Corredoira, F. Prada, M. C. Eliche

We present deep broad-band R and narrow-band Halpha images of Stephan's Quintet. The observations in the R band show that the diffuse halo of the Stephan's Quintet is larger than previously thought and extends out to NGC 7320C. However, we have not found emission connecting NGC 7331 and NGC 7320 to R ~ 26.7 mag/arcsec^2 (at more than 3-sigma level), so there

E. Ivanov

We give a brief account of supersymmetric Born-Infeld theories with extended supersymmetry, including those with partially broken supersymmetry. Some latest developments in this area are presented. One of them is N=3 supersymmetric Born-Infeld theory which admits a natural off-shell formulation in N=3 harmonic superspace.

A. K. Mohanty, A. V. S. S. Narayana Rao

The so called long range correlation properties of DNA sequences are studied using the variance analyses of the density distribution of a single or a group of nucleotides in a model independent way. This new method which was suggested earlier has been applied to extract slope parameters that characterize the correlation properties for several intron containi

K. D. Usadel, A. Hucht

The influence of uniaxial anisotropy and the dipole interaction on the direction of the magnetization of ultra-thin ferromagnetic films in the ground-state is studied. The ground-state energy can be expressed in terms of anisotropy constants which are calculated in detail as function of the system parameters and the film thickness. In particular non-collinea

G. Giardino, A. J. Banday, K. M. Gorski, K. Bennett

We have analysed the angular power spectra of the Parkes radio continuum and polarisation survey of the Southern galactic plane at 2.4 GHz. We have found that in the multipole range l=40-250 the angular power spectrum of the polarised intensity is well described by a power-law spectrum with fitted spectral index alpha_L = 2.37 +- 0.21. In the same multipole

Joachim Krug

Codeposition of impurities during the growth of a vicinal surface leads to an impurity concentration gradient on the terraces, which induces corresponding gradients in the mobility and the chemical potential of the adatoms. Here it is shown that the two types of gradients have opposing effects on the stability of the surface: Step bunching can be caused by i

Manoj K. Samal, Partha Ghose

It is suggested that the individual outcomes of a measurement process can be understood within standard quantum mechanics in terms of the measuring apparatus, treated as a quantum computer, executing Grover's search algorithm.

G S Khadekar, Vrishali Patki

Exact solution are obtained for a homogeneous spacially isotropic cosmological model in a matter free space with or without cosmological consant for a n-dimensional Kaluza-Klein type of metric in the rest mass varying theory of gravity proposed by Wesson[1983]. The behavior of the model is discussed.

E. A. Ivanov, B. M. Zupnik

We elaborate on a new representation of Lagrangians of 4D nonlinear electrodynamics including the Born-Infeld theory as a particular case. In this new formulation, in parallel with the standard Maxwell field strength $F_{\alpha\beta}, \bar{F}_{\dot\alpha\dot\beta}$, an auxiliary bispinor field $V_{\alpha\beta}, \bar{V}_{\dot\alpha\dot\beta}$ is introduced. T

Timothy J. Hollowood

In the context of softly-broken N=4 to N=2 supersymmetric SU(N) gauge theory, we calculate using semi-classical instanton methods, the lowest order non-trivial terms in the mass expansion of the prepotential for all instanton number. We find exact agreement with Seiberg-Witten theory and thereby achieve the most powerful test yet of this theory. We also calc

Daniele Tommasini

Einstein, Podolsky and Rosen (EPR) argued that the quantum-mechanical probabilistic description of physical reality had to be incomplete, in order to avoid an instantaneous action between distant measurements. This suggested the need for additional "hidden variables", allowing for the recovery of determinism and locality, but such a solution has been disprov

Michael Schröder

Averaging problems are ubiquitous in Finance with the valuation of the so-called Asian options on arithmetic averages as their most conspicuous form. There is an abundance of numerical work on them, and their stochastic structure has been extensively studied by Yor and his school. However, the analytical structure of these problems is largely unstudied. Our

Constantin Vernicos

Take a torus with a Riemannian metric. Lift the metric on its universal cover. You get a distance which in turn yields balls. On these balls you can look at the Laplacian. Focus on the spectrum for the Dirichlet or Neumann problem. We describe the asymptotic behaviour of the eigenvalues as the radius of the balls goes to infinity, and characterise the flat t

Michael Schröder

This note re-addresses the Paris barrier options proposed by Yor and collaborators and their valuation using the Laplace transform approach. The notion of Paris barrier options, based on excursion theory and using the Brownian meander, is extended such that their valuation is now possible at any point during their lifespan. The pertinent Laplace transforms a

Lucian-Cornel Crasovan, Gabriel Molina-Terriza, Juan P. Torres, Lluis Torner

We put forward the existence of a rich variety of fully stationary vortex structures, termed H-clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopola

Ye. S. Golubeva, W. Cassing, L. A. Kondratyuk

We study the perspectives of resonant and nonresonant charmed meson production in $\bar{p} + A$ reactions within the Multiple Scattering Monte Carlo (MSMC) approach. We calculate the production of the resonances $\Psi(3770), \Psi(4040)$ and $\Psi(4160)$ on various nuclei, their propagation and decay to $D, \bar{D}, D^*, \bar{D}^*, D_s, \bar{D}_s$ in the medi

P. Facchi

The evolution of a quantum system undergoing very frequent measurements takes place in a proper subspace of the total Hilbert space (quantum Zeno effect). When the measuring apparatus is included in the quantum description, the Zeno effect becomes a pure consequence of the dynamics. We show that for continuous measurement processes the quantum Zeno evolution

M. S. Laad, L. Craco, E. Müller-Hartmann

Motivated by the heavy fermion Fermi liquid (HFFL) features observed at low-$T$ in the pyrochlore $LiV_{2}O_{4}$, we consider a material-specific model that includes aspects of the local quantum chemistry, the geometrically frustrated lattice structure, and strong correlations in a {\it single} approach. In particular, we show how geometrical frustration (GF

Sang-Hyeon Ahn

Among a number of gamma-ray bursts whose host galaxies are known, GRB971214 stands out for its high redshift(z=3.25) and the Lya emission line having a P-Cygni type profile. which is interpreted to be a direct consequence of the expanding supershell. From a simple Voigt-fitting analysis, we estimate the expansion velocity of the supershell and the neutral co

Andrew S. Dancer, Ian A. B. Strachan

We give an elementary treatment of the existence of complete Kahler-Einstein metrics with nonpositive Einstein constant and underlying manifold diffeomorphic to the tangent bundle of the (n+1)-sphere.

D. R. Bowler, J. H. G. Owen

We describe how we have used tight binding calculations as a quick, efficient tool to search for possible structures of Bi nanolines on Si(001). After identifying promising candidate structures, we have concentrated on these with \textit{ab initio} electronic structure techniques. The energetics of the tight binding are shown to be in good agreement with the

J. H. G. Owen, K. Miki, H. Koh, H. W. Yeom

Stress resulting from mismatch between a substrate and an adsorbed material has often been thought to be the driving force for the self-assembly of nanoscale structures. Bi nanolines self-assemble on Si(001), and are remarkable for their straightness and length -- they are often more than 400 nm long, and a kink in a nanoline has never been observed. Through

A. Sibirtsev, K. Tsushima, S. Krewald

Within the meson exchange model we study $\omega$ meson photoproduction at energies above the s channel resonance region. Different model prescriptions for the $\omega{NN}$ vertex function are investigated imposing gauge invariance as well as crossing symmetry. The calculations reproduce the energy dependence of the differential $\omega$ photoproduction cros

L. Magrini, R. L. M. Corradi, N. A. Walton, A. A. Zijlstra

Five planetary nebulae (PNe) have been discovered in the nearby dwarf irregular galaxy. Emission line images were obtained using the Wide Field Camera of the 2.5m Isaac Newton Telescope (INT) at La Palma (Spain). The candidate PNe were identified by their point-like appearance and relatively strong [OIII] emission-line fluxes. They are located within a galac

J-L. Atteia, M. Boer, F. Cotin, J. Couteret

The gamma-ray detector of HETE-2, called FREGATE, has been designed to detect gamma-ray bursts in the energy range [6-400] keV. Its main task is to alert the other instruments of the occurrence of a gamma-ray burst (GRB) and to provide the spectral coverage of the GRB prompt emission in hard X-rays and soft gamma-rays. FREGATE was switched on on October 16,

A. R. Lima, G. Sauermann, H. J. Herrmann, K. Kroy

We present a model to describe the collective motion of barchan dunes in a field. Our model is able to reproduce the observation that a typical dune stays confined within a stripe. We also obtain some of the pattern structures which ressemble those observed from aerial photos which we do analyse and compare with the specific field of La\^ayounne.

Bernard J. Geurts

Buoyancy effects in unstably stratified mixing layers express themselves through gravity currents of heavy fluid which propagate in an ambient lighter fluid. These currents are encountered in numerous geophysical flows, industrial safety and environmental protection issues. During transition to turbulence a strong distortion of the separating interface betwe

Salvatore Micciche`, Giovanni Bonanno, Fabrizio Lillo, Rosario N. Mantegna

We investigate the historical volatility of the 100 most capitalized stocks traded in US equity markets. An empirical probability density function (pdf) of volatility is obtained and compared with the theoretical predictions of a lognormal model and of the Hull and White model. The lognormal model well describes the pdf in the region of low values of volatil

Masahide Sasaki, Alberto Carlini

Suppose that three kinds of quantum systems are given in some unknown states $\ket f^{\otimes N}$, $\ket{g_1}^{\otimes K}$, and $\ket{g_2}^{\otimes K}$, and we want to decide which \textit{template} state $\ket{g_1}$ or $\ket{g_2}$, each representing the feature of the pattern class ${\cal C}_1$ or ${\cal C}_2$, respectively, is closest to the input \textit{

A. D. Drozdov, J. deC. Christiansen

Tensile creep tests, tensile relaxation tests and a tensile test with a constant rate of strain are performed on injection-molded isotactic polypropylene at room temperature in the vicinity of the yield point. A constitutive model is derived for the time-dependent behavior of semi-crystalline polymers. A polymer is treated as an equivalent network of chains

C. Manwart, U. Aaltosalmi, A. Koponen, R. Hilfer

Numerical micropermeametry is performed on three dimensional porous samples having a linear size of approximately 3 mm and a resolution of 7.5 $\mu$m. One of the samples is a microtomographic image of Fontainebleau sandstone. Two of the samples are stochastic reconstructions with the same porosity, specific surface area, and two-point correlation function as

M. A. Perez-Torres, A. Alberdi, J. M. Marcaide, J. C. Guirado

We report here on 5 GHz global very-long-baseline interferometry (VLBI) observations of SN 1986J, 16 yr after its explosion. We obtained a high-resolution image of the supernova, which shows a distorted shell of radio emission, indicative of a deformation of the shock front. The angular size of the shell is $\sim4.7 {\rm mas}$, corresponding to a linear size

N. A. Mortensen, J. R. Folkenberg, P. M. W. Skovgaard, J. Broeng

We consider the problem of radiation into free space from the end-facet of a single-mode photonic crystal fiber (PCF). We calculate the numerical aperture NA=sin theta from the half-divergence angle theta ~ tan^{-1}(lambda/pi w) with pi w^2 being the effective area of the mode in the PCF. For the fiber first presented by Knight et al. we find a numerical ape

Masashi Ban, Masahide Sasaki, Masahiro Takeoka

A quantum channel is derived for continuous variable teleportation which is performed by means of an arbitrary entangled state and the standard protocol. When a Gaussian entangled state such as a two-mode squeezed-vacuum state is used, the continuous variable teleportation is equivalent to the thermalizing quantum channel. Continuous variable dense coding is

Roberto Casadio, Benjamin Harms, Octavian Micu

We investigate the idea that ultrahigh energy gamma-rays (E>10 TeV) can be produced when charged particles are accelerated by microscopic black holes. We begin by showing that microscopic black holes may exist as remnants of primordial black holes or as products of the collisions in the large extra dimensions scenario of high energy cosmic rays with atmosphe

T. P. Ilichova

A nonrelativistic decomposition for the quark energy by the ratio of the dispersion of quark momentum squared and the effective quark mass is investigated in the framework of the relativistic oscillator constituent quark model as bound systems of three valence quarks. It is shown that relativistic corrections are defined by dispersion of the squared absolute

T. P. Ilichova, S. G Shulga

The main statement of the nucleon constituent quark model with a fixed number of particles as basic ansatz are considered in a framework of the single-time (quasipotential) approach to the bound state problem. The scaling law breacking for the proton form factor is investigated for Q^2 = 0 -- 2 Gev^2.

Walter Dehnen

A novel code for the approximate computation of long-range forces between N mutually interacting bodies is presented. The code is based on a hierarchical tree of cubic cells and features mutual cell-cell interactions which are calculated via a Cartesian Taylor expansion in a symmetric way, such that total momentum is conserved. The code benefits from an impr