October 2002 arXiv papers — page 9

Michael Beyer

Superconductivity, superfluidity, condensation, cluster formation, etc. are phenomena that might occur in many-particle systems. These are due to residual interactions between the particles. To explain these phenomena consistently in a microscopic approach, at some point, one needs to solve few-body equations that are modified because of the Pauli principle

Tapas Sil, S. K. Samaddar, J. N. De, S. Shlomo

The liquid-gas phase transition in finite nuclei is studied in a heated liquid-drop model where the drop is assumed to be in thermodynamic equilibrium with the vapour emanated from it. Changing pressure along the liquid-gas coexistence line of the systems, symmetric or asymmetric, suggests that the phase transition is a continuous one. This is further corrob

A. Degasperis, S. V. Manakov, P. M. Santini

To study initial-boundary value problems for linear PDEs we have recently proposed two alternative approaches in Fourier space: the "analyticity appoach" and the "elimination by restriction approach". In this paper we present the analyticity appoach and we illustrate its power in studying the well-posedness of initial - boundary value problem

Hidetsugu Sakaguchi

We study numerically stick slip motions in a model of blocks and springs being pulled slowly. The sliding friction is assumed to change dynamically with a state variable. The transition from steady sliding to stick-slip is subcritical in a single block and spring system. However, we find that the transition is continuous in a long chain of blocks and springs

Hidetsugu Sakaguchi

Cooperative effects of periodic force and noise in globally Cooperative effects of periodic force and noise in globally coupled systems are studied using a nonlinear diffusion equation for the number density. The amplitude of the order parameter oscillation is enhanced in an intermediate range of noise strength for a globally coupled bistable system, and the

Gerhard Rein

We construct steady states of the Euler-Poisson system with a barotropic equation of state as minimizers of a suitably defined energy functional. Their minimizing property implies the non-linear stability of such states against general, i.e., not necessarily spherically symmetric perturbations. The mathematical approach is based on previous stability results

Toshiaki Fujiwara, Hiroshi Fukuda, Hiroshi Ozaki

We show that choreographic three bodies {x(t), x(t+T/3), x(t-T/3)} of period T on the lemniscate, x(t) = (x-hat+y-hat cn(t))sn(t)/(1+cn^2(t)) parameterized by the Jacobi's elliptic functions sn and cn with modulus k^2 = (2+sqrt{3})/4, conserve the center of mass and the angular momentum, where x-hat and y-hat are the orthogonal unit vectors defining the

Jim Pitman

This paper presents some general formulas for random partitions of a finite set derived by Kingman's model of random sampling from an interval partition generated by subintervals whose lengths are the points of a Poisson point process. These lengths can be also interpreted as the jumps of a subordinator, that is an increasing process with stationary inde

Damien Roy

In 1969, H. Davenport and W. Schmidt established a measure of simultaneous approximation for a real number ξand its square by rational numbers with the same denominator, assuming only that ξis not rational nor quadratic over Q. Here, we show by an example, that this measure is optimal. We also indicate several properties of the numbers for which this measure

Tristan Hubsch, Abdul Rahman

We study certain mild degenerations of algebraic varieties which appear in the analysis of a large class of supersymmetric theories, including superstring theory. We analyze Witten's sigma-model and find that the non-transversality of the superpotential induces a singularization and stratification of the ground state variety. This stratified variety (the

Constantin Vernicos

Take a riemanniann nilmanifold, lift its metric on its universal cover. In that way one obtains a metric invariant under the action of some co-compact subgroup. We use it to define metric balls and then study the spectrum of the laplacian for the dirichlet problem on them. We describe the asymptotic behaviour of the spectrum when the radius of these balls go

Julio C. Rebelo

In this work, under a mild assumption, we give the classification of the complete polynomial vector fields in two variables up to algebraic automorphisms of $\C^2$. The general problem is also reduced to the study of the combinatorics of certain resolutions of singularities. Whereas we deal with $\C$-complete vector fields, our results also apply to $\R$-com

Chandrashekhar Khare

In this note we consider questions about parametrisations of elliptic curves defined over number fields by quotients of the upper half-plane by finite index subgroups of SL_2(Z). We ask if we can choose such a parametrisation of an elliptic curve to reflect the field over which it is defined: this can be viewed as a generalisation of the Shimura-Taniyama-Wei

Chandrashekhar Khare

We prove a reciprocity law for one-dimensional compatible systems of mod p representations of absolute Galois groups of number fields. We prove that these arise from Hecke characters, and in particular recover by purely algebraic means the classical result (that is usually proven using deep results of Waldschmidt in transcendental number theory) that one-dim

Claudio Arezzo, Gang Tian

In this paper we explore the connection between special degenerations of algebraic manifolds and geodesics in the space of Kahler metrics. We provide a new and general geometric construction of nontrivial solutions for the geodesic equation. We show how to associate to any special nontrivial degeneration a geodesic of inifite length.

Kai Bruennler, Alessio Guglielmi

In this note we will show how to get consistency for first order classical logic, in a purely syntactic way, without going through cut elimination. The procedure is very simple and it uses the calculus of structures in an essential way. It also shows how finitaryness (in the sense of finite choice of premises for each rule) is actually a triviality (contrari

K. C. H. Mackenzie

The canonical involution of a double (=iterated) tangent bundle may be dualized in different ways to yield relations between the Tulczyjew diffeomorphism, the Poisson anchor associated with the standard symplectic structure on the cotangent space,and the reversal diffeomorphism. We show that the constructions which yield these maps extend very generally to t

Takeo Kojima, Hitoshi Konno

By using the elliptic analogue of the Drinfeld currents in the elliptic algebra U_{q,p}(\hat{sl}_N), we construct a L-operator, which satisfies the RLL-relations characterizing the face type elliptic quantum group B_{q,λ}(\hat{sl}_N). For this purpose, we introduce a set of new currents K_j(v) (1\leq j\leq N) in U_{q,p}(\hat{sl}_N). As in the N=2 case, we fi

Saeed Zakeri

This paper investigates the set of angles of the parameter rays which land on the real slice $[-2,1/4]$ of the Mandelbrot set. We prove that this set has zero length but Hausdorff dimension 1. We obtain the corresponding results for the tuned images of the real slice. Applications of these estimates in the study of critically non-recurrent real quadratics as

A. V. Jayanthan, J. K. Verma

Formulas are obtained in terms of complete reductions for the bigraded components of local cohomology modules of bigraded Rees algebras of 0-dimensional ideals in 2-dimensional Cohen-Macaulay local rings. As a consequence, cohomological expressions for the coefficients of the Bhattacharya polynomial of such ideals are obtained.

Peeter Puusemp

A {\it Schmidt group} is a non-nilpotent finite group in which each proper subgroup is nilpotent. Each Schmidt group G can be described by three parameters p, q and v, where p and q are different primes and v is a natural number, $v\ge 1$. Denote by ${\mathcal{S}}$ the class of all Schmidt groups which have the same parameters p, q and v. It is shown in this

Stefano Galatolo

In a topological dynamical system the complexity of an orbit is a measure of the amount of information (algorithmic information content) that is necessary to describe the orbit. This indicator is invariant up to topological conjugation. We consider this indicator of local complexity of the dynamics and provide different examples of its behavior, showing how

Dosang Joe, Bumsig Kim

We found an explicit description of all $GL(n,\RR)$-Whittaker functions as oscillatory integrals and thus constructed equivariant mirrors of flag manifolds. As a consequence we proved the Virasoro conjecture for flag manifolds.

Edward Swartz

Let K be the face ring of the independence complex of a matroid. We show that if T is a generic linear system of parameters, then K/T satisfies a weak form of the Hard Lefschetz Theorem. As a result, the first half of the h-vector of the complex satisfies inequalities similar to the g-theorem for simplicial polytopes.

Hsin-Ju Wang

In this paper, we derive several formulas of counting families of non-intersecting paths for two-sided ladder-shaped regions. As an application, we give a new proof to a combinatorial interpretation of Fibonacci numbers obtained by G. Andrews in 1974.

Damien Roy

It has been conjectured for some time that, for any integer n\ge 2, any real number ε>0 and any transcendental real number ξ, there would exist infinitely many algebraic integers αof degree at most n with the property that |ξ-α| < H(α)^{-n+ε}, where H(α) denotes the height of α. Although this is true for n=2, we show here that, for n=3, the optimal exponent

Y. Kosmann-Schwarzbach, K. C. H. Mackenzie

We demonstrate that the notions of derivative representation of a Lie algebra on a vector bundle, of semi-linear representations of a Lie group on a vector bundle, and related concepts, may be understood in terms of representations of Lie algebroids and Lie groupoids, and we indicate how these notions extend to derivative representations of Lie algebroids an

Linus Kramer, Katrin Tent

In this paper, we give a general group-theoretic construction of affine $\RR$-buildings, and more generally, of affine $Λ$-buildings, associated to semisimple Lie groups over nonarchimedean real closed fields. The construction of Kleiner-Leeb using the asymptotic cone of a Riemannian symmetric space appears as a special case. The explicit knowledge of the bu

Martin Grötschel, Martin Henk

A beautiful result of Bröcker and Scheiderer on the stability index of basic closed semi-algebraic sets implies, as a very special case, that every $d$-dimensional polyhedron admits a representation as the set of solutions of at most $d(d+1)/2$ polynomial inequalities. Even in this polyhedral case, however, no constructive proof is known, even if the quadrat

Yves André

We develop a $p$-adic version of the so-called Grothendieck-Teichmüller theory (which studies $Gal(\bar{\bf Q}/{\bf Q})$ by means of its action on profinite braid groups or mapping class groups). For every place $v$ of $\bar{\bf Q}$, we give some geometrico-combinatorial descriptions of the local Galois group $Gal(\bar{\bf Q}_v/{\bf Q}_v)$ inside $Gal(\bar{\

Gerald V. Dunne, Holger Gies, Christian Schubert

We analyze the relation between the short-distance behavior of quantum field theory and the strong-field limit of the background field formalism, for QED effective Lagrangians in self-dual backgrounds, at both one and two loop. The self-duality of the background leads to zero modes in the case of spinor QED, and these zero modes must be taken into account be

Robbert Dijkgraaf, Sergei Gukov, Vladimir A. Kazakov, Cumrun Vafa

We analyze perturbative aspects of gauged matrix models, including those where classically the gauge symmetry is partially broken. Ghost fields play a crucial role in the Feynman rules for these vacua. We use this formalism to elucidate the fact that non-perturbative aspects of N=1 gauge theories can be computed systematically using perturbative techniques o

P. Aschieri, L. Castellani, A. P. Isaev

Discretized nonabelian gauge theories living on finite group spaces G are defined by means of a geometric action \int Tr F\wedge *F . This technique is extended to obtain a discrete version of the Born-Infeld action.

Eugenio R. Bezerra de Mello, Yves Brihaye, Betti Hartmann

We study the direct interaction between global and local monopoles. While in two previous papers, the coupling between the two sectors was only indirect through the coupling to gravity, we here introduce a new term in the potential that couples the Goldstone field and the Higgs field directly. We investigate the influence of this term in curved space and com

A. Sugamoto

An exotic scenario of our universe is proposed in which our universe starts from zero space-time dimensions (0d), namely, a set of discrete points, it increases the (continuous) dimensionality during the cooling down of it, and finally arrives at the present four space-time dimensions (4d). This scenario may be called asymptotic disappearance (or discretizat

Veronika E Hubeny, Mukund Rangamani

We argue that pp-wave backgrounds can not admit event horizons. We also comment on pp-wave generalizations which would admit horizons and show that there exists a black string solution which asymptotes to a five dimensional plane wave background.

Latifa Elouadrhiri

Recent results from the Deeply Virtual Compton Scattering (DVCS) program at Jefferson Lab will be presented. Approved dedicated DVCS experiments at 6 GeV and plans for the 12 GeV upgrade will be discussed.

Ian Hinchliffe

At the LHC, new particles can be expected that decay to final states involving taus. Examples are given from simulations by the ATLAS experiment showing how such final states can be exploited.

R. Arnowitt, B. Dutta

We consider here the constraints in SUGRA models on the SUSY parameter space due to current experimental bounds on the light Higgs mass m_h, the b-> s gamma decay, the amount of neutralino cold dark matter Omega h^2, and the muon magnetic moment. Models with universal soft breaking (mSUGRA) and non-universal gaugino or Higgs masses at M_G are examined. For m

S. Groot Nibbelink, H. P. Nilles

In this talk we discus some properties of supersymmetric theories on orbifolds in five dimensions. The structure of FI--tadpoles may lead to (strong) localization of charged bulk scalars. Orbifold theories may suffer from various kinds of anomalies. The parity anomaly may render the construction of the orbifold theory ill--defined. The gauge anomaly on the o

Charanjit S. Aulakh

Using a simple Asymptotically Strong N=1 Susy SU(2) Gauge theory coupled to a {\bf{5}}-plet Chiral superfield we demonstrate the plausibility of the `` truly minimal &#39;&#39; Asymptotically Strong Grand Unification scenario proposed by us recently. Assuming a dynamical superpotential consistent with the symmetries and anomalies is actually induced non-pert

Stefano Laporta

In this paper we calculate at high-precision the expansions in e=(4-D)/2 of the master integrals of 4-loop vacuum bubble diagrams with equal masses, using a method based on the solution of systems of difference equations. We also show that the analytical expression of a related on-shell 3-loop self-mass master integral contains new transcendental constants m

R. Kaminski, L. Lesniak, B. Loiseau

Roy&#39;s equations, which incorporate crossing symmetry of the pion-pion scattering amplitudes, are used to resolve the present ambiguity between two solutions for the scalar-isoscalar phase shifts below 1 GeV. It is shown that the &#34;down-flat&#34; solution satisfies well Roy&#39;s equations and consequently crossing symmetry while the other solution cal

H. Eberl, W. Majerotto, V. C. Spanos

For energies relevant to future linear colliders, \sqrt{s} >~ 500 GeV, the WW fusion channel dominates the Higgs boson production cross section e+e- -> \barννh^0. We have calculated the one-loop corrections to this process due to fermion and sfermion loops in the context of the MSSM. As a special case, the contribution of the fermion loops in the SM has also

O. V. Utyuzh, G. Wilk, Z. Wlodarczyk

The limitations of the recently proposed new method of numerical modelling of Bose-Einstein correlations (BEC) are explicitly demonstrated. It is then argued that BEC should still be considered as emerging from the correlations of fluctuations, however they have to be modelled first in any Monte Carlo event generator (MCEG) and not added {\it a posteriori} t

W. Porod, W. Majerotto

We study lepton flavour violating signals at a future e+ e- linear collider within the general MSSM, allowing for the most general flavour structure. We demonstrate that there is a large region in parameter space with large signals, while being consistent with present experimental bounds on rare lepton decays such as mu -> e gamma. In our analysis, we includ

Roberto Ugoccioni

Forward-backward correlations are explored within the two-component clan model of multiparticle production. It is found that existing data are well described, and, in hh collisions, that clans must be allowed to leak particles from one hemisphere to the other. General formulae given for the symmetric case are then extended to the asymmetric one, which is rel

Youichi Yamada

Renormalization of two-loop divergent corrections to the vacuum expectation values (v_1, v_2) of the two Higgs doublets in the minimal supersymmetric standard model, and their ratio $\tanβ=v_2/v_1$, is discussed for general R_ξ gauge fixings. When the renormalized (v_1, v_2) are defined to give the minimum of the loop-corrected effective potential, it is sho

James D. Wells

Precision electroweak data suggests the existence of a light Standard Model Higgs boson. Its width is very narrow by an accident of the fermion mass hierarchies, and so slight perturbations to the theory induce dramatic changes in the phenomenology of direct Higgs boson production. Several theory ideas motivated by low-scale extra dimensions lead to a univer

Silas R. Beane, Martin J. Savage

Nucleon-nucleon scattering is studied to next-to-leading order in a partially-quenched extension of an effective field theory used to describe multi-nucleon systems in QCD. The partially-quenched nucleon-nucleon amplitudes will play an important role in relating lattice simulations of the two-nucleon sector to nature.

F. Palumbo

It is shown that starting from one and the same transfer matrix formulation of QCD on a lattice, it is possible to obtain both the action of Hasenfratz and Karsch as well as an action where the chemical potential is not coupled to the temporal links.

J. M. Zanotti, S. Choe, D. B. Leinweber, W. Melnitchouk

We present first results for masses of spin-3/2 baryons in lattice QCD, using a novel fat-link clover fermion action in which only the irrelevant operators are constructed using fat links. In the isospin-1/2 sector, we observe, after appropriate spin and parity projection, a strong signal for the J^P=3/2^- state, and find good agreement between the 1/2^+ mas

W. Melnitchouk, J. N. Hedditch, D. B. Leinweber, A. G. Williams

Masses of positive and negative parity excited nucleons and hyperons are calculated in quenched lattice QCD using an O(a^2) improved gluon action and a fat-link clover fermion action in which only the irrelevant operators are constructed with fat links. The results are in agreement with earlier N* simulations with improved actions, and exhibit a clear mass s

J. M. Zanotti, D. B. Leinweber, W. Melnitchouk, A. G. Williams

Hadron masses are calculated in quenched lattice QCD in order to probe the scaling behavior of a novel fat-link clover fermion action in which only the irrelevant operators of the fermion action are constructed using APE-smeared links. Light quark masses corresponding to an m_pi / m_rho ratio of 0.35 are considered to assess the exceptional configuration pro

Alan Weinstein

We review many of the contributions of the CLEO experiment to tau physics. Topics discussed are: branching fractions for major decay modes and tests of lepton universality; rare decays; forbidden decays; Michel parameters and spin physics; hadronic sub-structure and resonance parameters; the tau mass, tau lifetime, and tau neutrino mass; searches for CP viol

V. Daniel Elvira, P. Lebrun, P. Spentzouris

Geant4 is a tool kit developed by a collaboration of physicists and computer professionals in the High Energy Physics field for simulation of the passage of particles through matter. The motivation for the development of the Beam Tools is to extend the Geant4 applications to accelerator physics. Although there are many computer programs for beam physics simu

KTeV Collaboration, A. Alavi-Harati

The recent discovery of a large CP violating asymmetry in K(L) --> PI+ PI- E+ E- mode has prompted us to seach for the associated K(L) --> PI0 PI0 E+ E- decay mode in the KTeV-E799 experiment at Fermilab. In 2.7E+11 K(L) decays, one candidate event has been observed with an expected background of 0.3 event, resulting in an upper limit for the K(L) --> PI0 PI

Mark D. Goodsell, Carl E. Dolby, Stephen F. Gull

A coordinate system is set up for a general accelerating observer and is used to determine the particle content of the Dirac vacuum for that observer. Equations are obtained for the spatial distribution and total number of particles for massless fermions as seen by this observer, generalising previous work.

V. A. Berezin, A. L. Smirnov

In the case of crossing thin dust shells the momentum conservation law is found. For two crossing isotropic shells it coincides with the &#39;t Hooft-Dray formula. The system of one isotropic and one time-like shell is considered. In this case we found a very simple formula which relate velocities of dust shell before and after crossing.

G. Cella, E. Cuoco, G. M. Guidi

The standard procedure for detection of gravitational wave coalescing binaries signals is based on Wiener filtering with an appropriate bank of template filters. This is the optimal procedure in the hypothesis of addictive Gaussian and stationary noise. We study the possibility of improving the detection efficiency with a class of adaptive spectral identific

Anna Chame, Fabio D. A. Aarao Reis

We simulated a growth model in 1+1 dimensions in which particles are aggregated according to the rules of ballistic deposition with probability p or according to the rules of random deposition with surface relaxation (Family model) with probability 1-p. For any p>0, this system is in the Kardar-Parisi-Zhang (KPZ) universality class, but it presents a slow cr

J. Röhler

We discuss the static deformations of the doped CuO_2 lattices in YBa_2Cu_3O_x. Intrinsic lattice effects driven by the strong correlations of the electron system are separated from extrinsic chemical and bandstructure effects. c-axis displacements of the planar copper atoms seem to be a generic property of the metallic CuO_2 lattices.

S. J. L. Billinge

Recent atomic pair distribution function results from our group from manganites and cuprate systems are reviewed in light of the presence of multi-scale structures. These structures have a profound effect on the material properties

Volker Eyert

The results of first principles electronic structure calculations for the metallic rutile and the insulating monoclinic M1 phase of vanadium dioxide are presented. In addition, the insulating M2 phase is investigated for the first time. The density functional calculations allow for a consistent understanding of all three phases. In the rutile phase metallic

V. Podzorov, V. M. Pudalov, M. E. Gershenson

We report on fabrication and characterization of the organic field effect transistors (OFETs) on the surface of single crystals of rubrene. The parylene polymer film has been used as the gate insulator. At room temperature, these OFETs exhibit the p-type conductivity with the field effect mobility up to 1 cm^2/Vs and the on/off ratio ~ 10^4. The temperature

J. Fortagh, H. Ott, S. Kraft, A. Guenther

In this article, we describe an experimental system for generating Bose-Einstein condensates and controlling the shape and motion of the condensate by using miniaturised magnetic potentials. In particular, we describe the magnetic trap setup, the vacuum system, the use of dispenser sources for loading a high number of atoms into the magneto-optical trap, the

M. Arlego, D. C. Cabra, J. E. Drut, M. D. Grynberg

We study the interplay between a XY anisotropy $γ$, exchange modulations and an external magnetic field along the z direction in the XYZ chain using bosonization and Lanczos diagonalization techniques. We find an Ising critical line in the space of couplings which occur due to competing relevant perturbations which are present. More general situations are al

R. A. Duine, H. T. C. Stoof

A Feshbach resonance in the s-wave scattering length occurs if the energy of the two atoms in the incoming open channel is close to the energy of a bound state in a coupled closed channel. Starting from the microscopic hamiltonian that describes this situation, we derive the effective atom-molecule theory for a Bose gas near a Feshbach resonance. In order to

M. Calandra, O. Gunnarsson

We demonstrate that the resistivity data of a number of high Tc cuprates, in particular La(2-x)SrxCuO4, are consistent with resistivity saturation, although the Ioffe-Regel condition is strongly violated. By using the f-sum rule together with calculations of the kinetic energy in the t-J model, we show that the saturation resistivity is unusually large. This

Konstantin Klemm, Victor M. Eguiluz, Raul Toral, Maxi San Miguel

We analyze the non-equilibrium order-disorder transition of Axelrod&#39;s model of social interaction in several complex networks. In a small world network, we find a transition between an ordered homogeneous state and a disordered state. The transition point is shifted by the degree of spatial disorder of the underlying network, the network disorder favorin

J. L. Gavilano, D. Rau, S. Mushkolaj, H. R. Ott

We report the results of measurements of the dc-susceptibility and the 23Na-NMR response of Na2V2O7, a recently synthesized, non metallic low dimensional spin system. Our results indicate that upon reducing the temperature to below 100 K, the V^{4+} moments are gradually quenched, leaving only one moment out of 9 active. The NMR data reveal a phase transitio

ACC Coolen, C Perez-Vicente

We have studied two specific models of frustrated and disordered coupled Kuramoto oscillators, all driven with the same natural frequency, in the presence of random external pinning fields. Our models are structurally similar, but differ in their degree of bond frustration and in their finite size ground state properties (one has random ferro- and anti-ferro

Goran Johansson

We show how population inversion (PI) occurs in a two-level system (TLS) while measuring its charge using a capacitively coupled superconducting single-electron transistor (SSET), biased in the subgap regime, where the current through the SSET is carried by different cycles involving tunneling of both Cooper pairs and quasiparticles. The PI is directly assoc

Bikas K. Chakrabarti, Omjyoti Dutta

A simple electrical network model, having logical gate capacities, is proposed here for computations in plant cells. It is compared and contrasted with the animal brain network structure and functions.

K. Yamada, K. Kurahashi, T. Uefuji, M. Fujita

We report neutron scattering studies on single crystals of the electron-doped (n-type) superconducting cuprate Nd2-xCexCuO4 (x=0.15) with Tc = 18 K and 25 K. Unlike the hole-doped (p-type) superconducting cuprates where incommensurate magnetic fluctuations commonly exist, the n-type cuprate shows commensurate magnetic fluctuations at the tetragonal (1/2 1/2

Yoshiyuki Kabashima

The task of CDMA multiuser detection is to simultaneously estimate binary symbols of $K$ synchronous users from the received $N$ base-band CDMA signals. Mathematically, this can be formulated as an inference problem on a complete bipartite graph. In the research on graphically represented statistical models, it is known that the belief propagation (BP) can e

Joern Beckmann, Juergen Neuhaus

At FRM-II the installation of a user office software is under consideration, supporting tasks like proposal handling, beam time allocation, data handling and report creation. Although there are several software systems in use at major facilities, most of them are not portable to other institutes. In this paper the requirements for a modular and extendable us

Joern Beckmann, Joerg Pulz

A choice of wireless technologies is available today. Not all of them are suitable to be used in a instrument control network at a neutron scattering facility. This paper will start with an overview of the wireless communication protocols IrDA, IEEE 802.11 WLAN, Bluetooth and protocols used by cellular phones. Afterwards some thoughts on network layout and t

H. Kleines, M. Drochner, H. Loevenich, M. Wagener

In Forschungszentrum Juelich the control and data acquisition systems for several neutron spectrometers are being built. Because some of these spectrometers will be commissioned to the new research reactor FRM-II at the technical university of Munich, there was a joint effort with the instrumentation group of the FRM-II to establish the &#34;Juelich-Munich s

Antonio Di Lorenzo, Luigi Amico, Kazuhiro Hikami, Andreas Osterloh

We study descendants of inhomogeneous vertex models with boundary reflections when the spin-spin scattering is assumed to be quasi--classical. This corresponds to consider certain power expansion of the boundary-Yang-Baxter equation (or reflection equation). As final product, integrable $su(2)$-spin chains interacting with a long range with $XXZ$ anisotropy

R. T. Clay, S. Mazumdar, D. K. Campbell

We examine critically two different recently proposed models of charge ordering in the nominally 1/4-filled organic charge transfer solids (CTS). In one dimension, the two models are characterized by site charge densities of the form ...1010... and ...1100..., respectively. We establish the following theoretical results: 1) there exists a critical nearest-ne

Oleg Y. Gnedin

Despite the rapid observational progress in the study of young massive star clusters, the formation of globular clusters still remains poorly understood. Yet, it is emerging that globular cluster formation is intimately linked to the formation of the Galaxy. I discuss a generic scenario of the cluster formation within progenitor galaxies, based on the availa

D. S. Shepherd, L. Testi, D. P. Stark

We present 2&#34; to 7&#34; resolution 3 mm continuum and CO(J=1-0) line emission and near infrared Ks, H2, and [FeII] images toward the massive star forming region W75 N. The CO emission uncovers a complex morphology of multiple, overlapping outflows. A total flow mass of greater than 255 Msun extends 3 pc from end-to-end and is being driven by at least fou

Kailash C. Sahu, Ronald L. Gilliland

In this paper, we explore the astrophysical implications of near-field microlensing and its effects on stellar transit observations, with a special emphasis on the Kepler mission. Kepler is a NASA-approved mission whose goal is to detect a large number of extrasolar, earth-like planets by obtaining near-continuous photometry of > 100,000 F, G, and K dwarfs f

Joydeep Bagchi

New multi-wavelength (radio, optical & X-rays) observational evidences are presented which show that the nearby (z=0.046), rich cluster of galaxies Abell 3376 is experiencing a major event of binary subcluster merger. The key evidence is the discovery of a pair of large, optically unidentified diffuse radio sources (`arcs&#39;), symmetrically located about 2

C. Vignali, F. E. Bauer, D. M. Alexander, W. N. Brandt

We present X-ray spectral analyses of the three z>4 Active Galactic Nuclei (AGNs) thus far spectroscopically identified in the Chandra Deep Field-North Survey, at redshifts of 5.186, 4.424, and 4.137. These analyses are made possible by the extremely deep exposure (2 Ms) and the low Chandra background. The rest-frame 2.5-40 keV spectra are the first for opti

Robert Williams, Edward B. Jenkins, Jack A. Baldwin, Brian Sharpee

Recent analyses of nebular spectra have resulted in discrepant abundances from CNO forbidden and recombination lines. We consider independent methods of determining ion abundances for emission nebulae, comparing ion emission measures with column densities derived from resonance absorption lines viewed against the central star continuum. Separate analyses of

J. M. Paredes, M. Ribo, E. Ros, J. Marti

We present here new observations conducted with the EVN and MERLIN of the persistent microquasar LS 5039 discovered by Paredes et al. (2000) with the VLBA. The new observations confirm the presence of an asymmetric two-sided jet reaching up to 1000 AU on the longest jet arm. The results suggest a bending of the jets with increasing distance from the core and

Hagai Netzer

The empirical relationship between the broad line region size and the source luminosity in active galactic nuclei (AGNs) is used to obtain black holes (BH) masses for a large number of quasars in three samples. The largests BH masses found exceed 10^{10} Msun and are correlated, almost linearly, with the source luminosity. Such BH masses, when converted to g

M. Lemoine-Busserolle, T. Contini, R. Pello, J. -F. Le Borgne

We present VLT/ISAAC near-infrared spectroscopy of two gravitationally-lensed z ~ 1.9 galaxies, A2 and S2, located behind the cluster AC 114. Thanks to large magnification factors, we have been successful in detecting rest-frame optical emission lines in star-forming galaxies 1 to 2 magnitudes fainter than in previous studies of Lyman break galaxies (LBGs) a

J. Machalski, K. T. Chyzy, M. Jamrozy

A time evolution of giant lobe-dominated radio galaxies (with projected linear size $D>1$ Mpc) is analysed on the basis of dynamical evolution of the entire FRII-type population. Two basic physical parameters, namely the jet power $Q_{0}$ and central density of the galaxy nucleus $ρ_{0}$ are derived for a sample of giants with synchrotron ages reliably deter

Yulia Artemova, Igor Novikov

Gravity warps space and time into a funnel and generates a black hole when a cosmic body undergoes a catastrophic collapse. What can one say about the interior of a black hole? The important point is that inside a black hole the space radial direction becomes time, and time becomes a space direction. The path into the gravitational abyss of the interior of a

G. Aronica, E. Athanassoula, M. Bureau, A. Bosma

We present a near-infrared K_n-band photometric study of edge-on galaxies with a box/peanut-shaped `bulge&#39;. The morphology of the galaxies is analysed using unsharp masking and fits to the vertical surface brightness profiles, and the results are compared to N-body simulations and orbital calculations of barred galaxies. Both theoretical approaches repro

Bryan Gaensler, Heath Jones, Ben Stappers

We report the discovery of an H-alpha-emitting bow-shock nebula powered by the nearby millisecond pulsar J2124-3358. The bow shock is very broad, and is highly asymmetric about the pulsar&#39;s velocity vector. This shape is not consistent with that expected for the case of an isotropic wind interacting with a homogeneous ambient medium. Models which invoke

Antonio Pipino, Francesca Matteucci

We present a new model for the chemical evolution of elliptical galaxies taking into account SN feedback, detailed nucleosynthesis and galactic winds. We discuss the effect of galactic winds on the chemical enrichment of the ICM and compute the energy per particle injected by the galaxies into the ICM.

Timothy Fleming, James M. Stone

Using numerical MHD simulations, we have studied the evolution of the magnetorotational instability in stratified accretion disks in which the ionization fraction (and therefore resistivity) varies substantially with height. This model is appropriate to dense, cold disks around protostars or dwarf nova systems which are ionized by external irradiation of cos

Francesca Matteucci

We are briefly introducing the most important ingredients to study galactic evolution. In particular the roles of star formation, nucleosynthesis and gas flows. Then we are discussing the two different approaches to galactic evolution: the stellar population approach (chemical evolution models) and the hierarchical clustering scenario for galaxy formation. I

Keith Horne, Kirk T Korista, Michael R Goad

Reverberation mapping uses time-delayed variations in photoionised emission lines to map the geometry and kinematics of emission-line gas in active galactic nuclei. In previous work, the light travel time delay tau=R(1+cos(theta))/c and Doppler shift v give a 2-d map Psi(tau,v) for each emission line. Here we combine the velocity-delay information with photo

Sergey Kuznetsov

The RXTE observations of Scorpius X-1 in 1996-1999 are presented. The properties of its quasi-periodic X-ray oscillations are studied in detail. The results obtained are used for analysis in terms of the transition-layer model (TLM) and the relativistic-precession model (RPM) for a slowly rotating neutron star. Theoretical predictions of the two models are c

G. Fiorentini, C. Rolfs, F. L. Villante, B. Ricci

Experimental results for sub-barrier nuclear fusion reactions show cross section enhancements with respect to bare nuclei which are generally larger than those expected according to electron screening calculations. We point out that energy spread of target or projectile nuclei is a mechanism which generally provides fusion enhancement. We present a general f