March 2000 arXiv papers — page 9

Johannes Ruoff

We present a new derivation of the perturbation equations governing the oscillations of relativistic non-rotating neutron star models using the ADM-formalism. This formulation has the advantage that it immediately yields the evolution equations in a hyperbolic form, which is not the case for the Einstein field equations in their original form. We show that t

B. C. Allanach, A. Dedes

We propose a new scenario that solves the slepton negative mass squared problem of the minimal supersymmetric standard model with anomaly mediated supersymmetry breaking. The solution is achieved by including three trilinear R-parity violating operators in the superpotential. The soft supersymmetry breaking terms satisfy renormalisation group invariant relat

John Crisp, Luis Paris

It was conjectured by Tits that the only relations amongst the squares of the standard generators of an Artin group are the obvious ones, namely that a^2 and b^2 commute if ab=ba appears as one of the Artin relations. In this paper we prove Tits' conjecture for all Artin groups. More generally, we show that, given a number m(s)>1 for each Artin generator

Marc Lackenby

A taut ideal triangulation of a 3-manifold is a topological ideal triangulation with extra combinatorial structure: a choice of transverse orientation on each ideal 2-simplex, satisfying two simple conditions. The aim of this paper is to demonstrate that taut ideal triangulations are very common, and that their behaviour is very similar to that of a taut fol

Christophe Mayen, Genevieve Soucail

When the logarithmic slope of the galaxy counts is lower than 0.4 (this is the case in all filters at large magnitude), the magnification bias due to the lens makes the number density of objects decrease, and consequently, the radial distribution shows a typical depletion curve. In this paper, we present simulations of depletion curves obtained in different

James Binney, Nicolai Bissantz, Ortwin Gerhard

We generalize to elliptical models the argument of Kuijken (1997), which connects the microlensing optical depth towards the Galactic bulge to the Galactic rotation curve. When applied to the latest value from the MACHO collaboration for the optical depth for microlensing of bulge sources, the argument implies that the Galactic bar cannot plausibly reconcile

Stephan Dürr

The concept of simulating a variant of QCD with sea quarks which interact with the gluon configuration only via global gluonic quantities like $\int F\tilde F dx$ and $\int FF dx$ is tested for the case of the massive 2-flavour Schwinger model. It is found to amount to an importance sampling method which generates -at essentially the costs of a quenched run-

P. H. Damgaard, K. Splittorff

We describe a novel framework for partially quenched chiral perturbation theory based on the replica method. The computational rules are exceedingly simple. We illustrate these rules by computing the partially quenched chiral condensate to one-loop order. By considering arbitrary chiral $k$-point functions we show explicitly to one-loop order the equivalence

N. D. Lambert, G. W. Gibbons

We discuss the existance of smooth soliton solutions which interpolate between supersymmetric vacua in odd-dimensional theories. In particular we apply this analysis to a wide class of supergravities to argue against the existence of smooth domain walls interpolating between supersymmetric vacua. We find that if the superpotential changes sign then any Golds

M. Bando, T. Kugo, K. Yoshioka

We study a supersymmetric E6 grand unified model in which the SU(5) 5^* components are twisted in the third generation 27. Supplementing the adjoint Higgs field to a model analyzed previously, we calculate the mass matrices for the up and down quarks and charged leptons. Although the number of free parameters is less than that of observables, an overall fitt

Verena Schön, Michael Thies

We study two-dimensional, large $N$ field theoretic models (Gross-Neveu model, 't Hooft model) at finite baryon density near the chiral limit. The same mechanism which leads to massless baryons in these models induces a breakdown of translational invariance at any finite density. In the chiral limit baryonic matter is characterized by a spatially varying

H. V. Klapdor-Kleingrothaus, H. Päs, A. Y. Smirnov

The relations between the effective Majorana mass of the electron neutrino, $m_{ee}$, responsible for neutrinoless double beta decay, and the neutrino oscillation parameters are considered. We show that for any specific oscillation pattern $m_{ee}$ can take any value (from zero to the existing upper bound) for normal mass hierarchy and it can have a minimum

K. Takenaga

Supersymmetric ground state wave functions of a model of supersymmetric quantum mechanics on $S^1$ (supersymmetric simple pendulum) are studied. Supersymmetry can be broken due to the existence of an undetermined parameter, which is interpreted as a gauge field and appears as a firm consequence of quantization on a space with a nontrivial topology such as $S

C. Bizdadea, E. M. Cioroianu, S. O. Saliu

Consistent interactions among a set of two-form gauge fields in four dimensions are derived along a Hamiltonian cohomological procedure. It is shown that the deformation of the BRST charge and BRST-invariant Hamiltonian for the free model leads to the Freedman-Townsend interaction vertex. The resulting interaction deforms both the gauge transformations and r

V. Skalsky

The increase in mass of our observed expansive and isotropic relativistic Universe in the present relativistic cosmology is explained by the extensive assumption of the matter objects emerging on the horizon (of the most remote visibility). However, the physical analysis unambiguously shows that this assumption contradicts the theory of relativity, quantum m

A. Lazarian, B. T. Draine

We show that the energy-level splitting arising from grain rotation ensures that paramagnetic dissipation acts at its maximum rate, i.e., the conditions for paramagnetic resonance are automatically fulfilled. We refer to this process as ``resonance relaxation''. The differences between the predictions of classical Davis-Greenstein relaxation and reso

J. H. Samson

Numerical evaluation of functional integrals usually involves a finite (L-slice) discretization of the imaginary-time axis. In the auxiliary-field method, the L-slice approximant to the density matrix can be evaluated as a function of inverse temperature at any finite L as $ρ_L(β)=[ρ_1(β/L)]^L$, if the density matrix $ρ_1(β)$ in the static approximation is k

C. R. Hagen

The problem of calculating the Casimir force on two conducting planes by means of the stress tensor is examined. The evaluation of this quantity is carried out using an explicit regularization procedure which has its origin in the underlying (2+1) dimensional Poincaré invariance of the system. The force between the planes is found to depend on the ratio of t

Vernon Armitage, Alice Rogers

By adapting Feynman's sum over paths method to a quantum mechanical system whose phase space is a torus, a new proof of the Landsberg-Schaar identity for quadratic Gauss sums is given. In contrast to existing non-elementary proofs, which use infinite sums and a limiting process or contour integration, only finite sums are involved. The toroidal nature of

H. Schadwinkel, V. Gomer, U. Reiter, B. Ueberholz

Isolation of a single atomic particle and monitoring its resonance fluorescence is a powerful tool for studies of quantum effects in radiation-matter interaction. Here we present observations of quantum dynamics of an isolated neutral atom stored in a magneto-optical trap. By means of photon correlations in the atom's resonance fluorescence we demonstrat

Ph. Blanchard, R. Olkiewicz

Notions of robust and "classical" states for an open quantum system are introduced and discussed in the framework of the isometric-sweeping decomposition of trace class operators. Using the predictability sieve proposed by Zurek, ``quasi-classical'' states are defined. A number of examples illustrating how the ``quasi-classical'' stat

Michael Dickson

Bedard has argued that the 'minimalist' interpretation of Bohm's theory "do[es] not make sense", essentially because one cannot account for bonding properties in terms of particles cofigurations alone. I argue that while this point is correct, the minimalist interpretation never sought to provide such an explanation (nor is it incumbant u

Shi-Hai Dong

By applying an ansatz to the eigenfunction, an exact closed form solution of the Schrödinger equation in 2D is obtained with the potentials, $V(r)=ar^2+br^4+cr^6$, $V(r)=ar+br^2+cr^{-1}$ and $V(r)=ar^2+br^{-2}+cr^{-4}+dr^{-6}$, respectively. The restrictions on the parameters of the given potential and the angular momentum $m$ are obtained.

N. Garcia, A. Levanyuk, V. V. Osipov

We show that strong electric fields occurring in water near the surface of collapsing gas bubbles because of the flexoelectric effect can provoke dynamic electric breakdown in a micron-size region near the bubble and consider the scenario of the SBSL. The scenario is: (i) at the last stage of incomplete collapse of the bubble the gradient of pressure in wate

N. Garcia, V. V. Osipov

We show that very small-amplitude oscillations of a highly symmetric, spheric or cylindrical, interface (thin membrane) between two fluids can result in inhomogeneous instability and breaking of the interface symmetry: the frequency of the breathing vibration selects the spatial symmetry. This mechanism may govern morphogenesis.

P. Bouyer, V. Boyer, S. G. Murdoch, G. Delannoy

We present the design of our iron-core electromagnet for BEC, and how to solve the specific experimental problems raised by this technique. After presenting the experimental set-up, we address the interruption of runaway evaporative cooling when the Zeeman effect is not linear. We present the ways to circumvent this problem, use of multiple RF frequencies, s

K. M. O'Hara, S. R. Granade, M. E. Gehm, T. A. Savard

We demonstrate an ultrastable CO2 laser trap that provides tight confinement of neutral atoms with negligible optical scattering and minimal laser-noise- induced heating. Using this method, fermionic 6Li atoms are stored in a 0.4 mK deep well with a 1/e trap lifetime of 300 sec, consistent with a background pressure of 10^(-11) Torr. To our knowledge, this i

A. L. Lin, A. Hagberg, A. Ardelea, M. Bertram

We investigate pattern formation in self-oscillating systems forced by an external periodic perturbation. Experimental observations and numerical studies of reaction-diffusion systems and an analysis of an amplitude equation are presented. The oscillations in each of these systems entrain to rational multiples of the perturbation frequency for certain values

Michael Blank

By means of a novel variational approach and using dual maps techniques and general ideas of dynamical system theory we derive exact results about several models of transport flows, for which we also obtain a complete description of their limit (in time) behavior in the space of configurations. Using these results we study the motion of a speedy passive part

Guillermo J. Ortega, Enrique Louis

Statistical differentiability of the measure along the reconstructed trajectory is a good candidate to quantify determinism in time series. The procedure is based upon a formula that explicitly shows the sensitivity of the measure to stochasticity. Numerical results for partially surrogated time series and series derived from several stochastic models, illus

C. Quesne, N. Vansteenkiste

$C_λ$-extended oscillator algebras generalizing the Calogero-Vasiliev algebra, where $C_λ$ is the cyclic group of order $λ$, are studied both from mathematical and applied viewpoints. Casimir operators of the algebras are obtained, and used to provide a complete classification of their unitary irreducible representations under the assumption that the number

J. Guerrero, V. Aldaya

We provide an explicit construction of quasi-invariant measures on polarized coadjoint orbits of a Lie group G. The use of specific (trivial) central extensions of G by the multiplicative group ${R}^+$ allows us to restore the strict invariance of the measures and, accordingly, the unitarity of the quantization of coadjoint orbits. As an example, the represe

Laszlo Erdos

We establish the exact low-energy asymptotics of the integrated density of states (Lifschitz tail) in a homogeneous magnetic field and Poissonian impurities with a repulsive single-site potential of Gaussian decay. It has been known that the Gaussian potential tail discriminates between the so-called "classical" and "quantum" regimes, and pre

M. Bramson, J. L. Lebowitz

Consider the system of particles on ${\Bbb Z}^d$ where particles are of two types, $A$ and $B$, and execute simple random walks in continuous time. Particles do not interact with their own type, but when a type $A$ particle meets a type $B$ particle, both disappear. Initially, particles are assumed to be distributed according to homogeneous Poisson random fi

Anne Heyworth

This thesis concentrates on the development and application of rewriting and Groebner basis methods to a range of combinatorial problems. Chapter Two contains the most important result, which is the application of Knuth-Bendix procedures to Kan extensions, showing how rewriting provides a useful method for attempting to solve a variety of combinatorial probl

Alexander Shnirelman

The author studies the flows of an ideal incompressible fluid in a 2-dimensional domain, and in particular questions of instability and controllability.

Weiping Li

To an integral homology 3-sphere $Y$, we assign a well-defined $\Z$-graded (monopole) homology $MH_*(Y, I_{\e}(\T; \e_0))$ whose construction in principle follows from the instanton Floer theory with the dependence of the spectral flow $I_{\e}(\T; \e_0)$, where $\T$ is the unique U(1)-reducible monopole of the Seiberg-Witten equation on $Y$ and $\e_0$ is a r

G. Laumon

This is the text of a Bourbaki lecture that I gave on March 12, 2000.

Jinho Baik, Eric Rains

The purpose of this paper is to investigate the limiting distribution functions for a polynuclear growth model with two external sources, which was considered by Prähofer and Spohn. Depending on the strength of the sources, the limiting distribution functions are either the Tracy-Widom functions of random matrix theory, or a new explicit function which has t

Inna Sysoeva

In 1996 E. Formanek classified all the irreducible complex representations of $B_n$ of dimension at most $n-1,$ where $B_n$ is the Artin braid group on $n$ strings. In this paper we extend this classification to the representations of dimension $n,$ for $n\geq 9$. We prove that all such representations are equivalent to a tensor product of a one-dimensional

Meike Akveld, Dietmar Salamon

The main theorem of this paper asserts that the inclusion of the space of projective Lagrangian planes into the space of Lagrangian submanifolds of complex projective space induces an injective homomorphism of fundamental groups. We introduce three invariants of exact loops of Lagrangian submanifolds that are modelled on invariants introduced by Polterovich

M. Bianchi, S. Kovacs, G. C. Rossi, Ya. S. Stanev

We compute four-point correlation functions of scalar composite operators in the N=4 supercurrent multiplet at order g^4 using the N=1 superfield formalism. We confirm the interpretation of short-distance logarithmic behaviours in terms of anomalous dimensions of unprotected operators exchanged in the intermediate channels and we determine the two-loop contr

Christian Brouder, Alessandra Frabetti

The renormalized photon and electron propagators are expanded over planar binary trees. Explicit recurrence solutions are given for the terms of these expansions. In the case of massless Quantum Electrodynamics (QED), the relation between renormalized and bare expansions is given in terms of a Hopf algebra structure. For massive quenched QED, the relation be

E. J. Beggs, P. R. Johnson

We compute the braiding for the `principal gradation' of $U_q(\hat{{\it sl}_2})$ for $|q|=1$ from first principles, starting from the idea of a rigid braided tensor category. It is not necessary to assume either the crossing or the unitarity condition from S-matrix theory. We demonstrate the uniqueness of the normalisation of the braiding under certain a

G. Bertoldi, J. M. Isidro, M. Matone, P. Pasti

We consider the compactification M(atrix) theory on a Riemann surface Sigma of genus g>1. A natural generalization of the case of the torus leads to construct a projective unitary representation of pi_1(Σ), realized on the Hilbert space of square integrable functions on the upper half--plane. A uniquely determined gauge connection, which in turn defines a ga

C. Bizdadea

A Hamiltonian BRST deformation procedure for obtaining consistent interactions among fields with gauge freedom is proposed. The general theory is exemplified on the three-dimensional Chern-Simons model.

C. Bizdadea, M. G. Mocioaca, S. O. Saliu

An irreducible cohomological derivation of the Freedman-Townsend vertex in four dimensions is given.

C. Bizdadea, L. Saliu, S. O. Saliu

Consistent interactions between Yang-Mills gauge fields and an abelian 2-form are investigated by using a Hamiltonian cohomological procedure. It is shown that the deformation of the BRST charge and the BRST-invariant Hamiltonian of the uncoupled model generates the Yang-Mills Chern-Simons interaction term. The resulting interactions deform both the gauge tr

C. J. Efthimiou, D. A. Spector

This document is an introduction to and review of two-dimensional mathematical physics. The reader is introduced to the subject matter primarily through problems, which are presented along with detailed worked solutions. For each chapter, there is a brief summary of important results and ideas that precedes the problems and the solutions. This document can b

Laurent Lellouch

I present quenched, lattice QCD calculations of the hadronic matrix elements relevant for B^0_{d(s)}-\bar B^0_{d(s)} and K^0-\bar K^0 mixing and briefly review the status of lattice predictions.

M. M. Block, F. Halzen, G. Pancheri, T. Stanev

We make a QCD-inspired parameterization of all accelerator data on forward proton-proton and antiproton-proton scattering amplitudes. Using vector dominance and the additive quark model, we show that the same parameters also fit gamma p and gamma gamma interactions. Using the high energy predictions of our model, along with Glauber theory, we calculate proto

Robert Bluhm, V. Alan Kostelecky, Neil Russell

A theoretical analysis is made of experiments in hydrogen and antihydrogen that test CPT. We show that these experiments also provide sensitive tests of Lorentz symmetry for protons and electrons. Both 1S-2S transitions and Zeeman hyperfine splittings in the ground state are examined. We find that sensitivity to CPT and Lorentz violation at the level of $10^

P. M. Zerwas

The physics potential is briefly summarized for an e+e- linear collider operating at center-of-mass energies up to \sqrt{s} = 1 TeV and delivering integrated luminosities up to \int L = 0.5 ab^(-1) in one to two years. This machine will allow us to perform precision studies of the top quark and the electroweak gauge bosons at the per-mille level. It will be

X. -J. Wang, M. -L. Yan

We study $ω\toπ^+π^-$ decay up to including all orders of the chiral expansion and one-loop level of mesons in formlism of chiral constituent quark model. This G-parity forbidden decay is caused by $m_u\neq m_d$ and electromagnetic interaction of mesons. We illustrate that in the formlism both nonresonant contact interaction and $ρ$ resonance exchange contri

A. V. Kuznetsov, N. V. Mikheev, D. A. Rumyantsev

The process of the lepton pair production by a neutrino propagating in an external electromagnetic field is investigated in the framework of the Standard Model. Relatively simple exact expression for the probability as the single integral is obtained, which is suitable for a quantitative analysis.

Deog Ki Hong

In this talk, I discuss the recent development in color superconductivity in terms of effective field theory. By investigating the Cooper pair gap equations at high density, we see that the effective theory simplifies the gap analysis very much, especially in finding the ground state, the precise form of the gap, and the critical temperature. Furthermore, th

Shailesh Chandrasekharan, Uwe-Jens Wiese

Motivated by the SO(5) theory of high-temperature superconductivity and antiferromagnetism, we ask if an SO(10) theory unifies color superconductivity and chiral symmetry breaking in QCD. The transition to the color superconducting phase would then be analogous to a spin flop transition. While the spin flop transition generically has a unified SO(3) descript

J. M. Laget

At forward angles, the cross-sections of photoproduction of vector mesons ($ρ$, $ω$, and $ϕ$) are well accounted for by the exchange of the Pomeron at high energies, while contributions of $t$ channel exchange of Reggeons are significant at low energies. At large angles, the impact parameter becomes small enough to prevent their constituents to build up the

S. V. Krasnikov

In this talk I discuss pertinence of the wormholes to the problem of circumventing the light speed barrier and present a specific class of wormholes. The wormholes of this class are static and have arbitrarily wide throats, which makes them traversable. The matter necessary for these spacetimes to be solutions of the Einstein equations is shown to consist of

Bin Wang, Elcio Abdalla

General geodesic equations of the motion of spinning systems around the (3+1)-dimensional and (2+1)-dimensional rotating anti-de Sitter black holes have been obtained. Based upon these equations, we derived the entropy bound for a rotating system from Kerr-Anti de Sitter black holes and BTZ black holes, respectively. Our result coincides with that of Hod&#39

Remo Garattini

The entropy for a black hole in a de Sitter space is approached within the framework of spacetime foam. A simple model, made by $N$ wormholes in a semiclassical approximation, is taken under examination to compute the entropy for such a case. An extension to the extreme case when the black hole and cosmological horizons are equal is discussed.

S. Capozziello, A. Feoli, G. Lambiase, G. Papini

Massive, spinless bosons have vanishing probability of reaching the sphere r=2M from the region r>2M when the original Schwarzschild metric is modified by maximal acceleration corrections.

S. Capozziello, G. Lambiase

The Berry phase of mixed states, as neutrino oscillations, is calculated in a accelerating and rotating reference frame. It turns out to be depending on the vacuum mixing angle, the mass--squared difference and on the coupling between the momentum of the neutrino and the spinorial connection. Berry's phase for solar neutrinos and its geometrical aspects

Chitta Baral, Miroslaw Truszczynski

The papers gathered in this collection were presented at the 8th International Workshop on Nonmonotonic Reasoning, NMR2000. The series was started by John McCarthy in 1978. The first international NMR workshop was held at Mohonk Mountain House, New Paltz, New York in June, 1984, and was organized by Ray Reiter and Bonnie Webber. In the last 10 years the area

Jason W. H. Lee, Y. C. Tay, Anthony K. H. Tung

Ports, warehouses and courier services have to decide online how an arriving task is to be served in order that cost is minimized (or profit maximized). These operators have a wealth of historical data on task assignments; can these data be mined for knowledge or rules that can help the decision-making? MOO is a novel application of data mining to online opt

Charlie Volkstorf

We introduce a set of eight universal Rules of Inference by which computer programs with known properties (axioms) are transformed into new programs with known properties (theorems). Axioms are presented to formalize a segment of Number Theory, DataBase retrieval and Computability Theory. The resulting Program Calculus is used to generate programs to (1) Det

G. Tarjus, D. Kivelson

The viscous slowing down of supercooled liquids that leads to glass formation can be considered as a classical, and is assuredly a thoroughly studied, example of a "jamming process". In this review, we stress the distinctive features characterizing the phenomenon. We also discuss the main theoretical approaches, with an emphasis on the concepts (free

R. S. Mendes, C. Anteneodo

A family of wave packets with power law tails are employed to analyze the long time dependence of the corresponding probability density. The densities, associated to packets for free particles in the one-dimensional space, with sufficiently long tails decay asymptotically in time following a $t^{-β}$ law (with $β<1$), slower than the usual $t^{-1}$ one, incl

Renio S. Mendes, Constantino Tsallis

We analyze a simple classical Hamiltonian system within the hypothesis of renormalizability and isotropy that essentially led Maxwell to his ubiquitous Gaussian distribution of velocities. We show that the equilibrium-like power-law energy distribution emerging within nonextensive statistical mechanics satisfies these hypothesis, in spite of not being factor

M. L. Chiofalo, M. P. Tosi

We present numerical studies of atomic transport in 3D and 1D models for a mode-locked, pulsed atom laser as realized by Anderson and Kasevich [Science 281 (1998) 1686] using an elongated Bose condensate of ${}^{87}$Rb atoms poured into a vertical optical lattice. From our 3D results we ascertain in a quantitative manner the role of mean-field interactions i

M. E. S. Borelli, H. Kleinert

The phase diagram of an incompressible fluid membrane subject to quantum and thermal fluctuations is calculated exactly in a large number of dimensions of configuration space. At zero temperature, a crumpling transition is found at a critical bending rigidity $1/α_{\rm c}$. For membranes of fixed lateral size, a crumpling transition occurs at nonzero tempera

H. Mayaffre, M. Horvatic, C. Berthier, M. -H. Julien

The magnetic field-induced 3D ordered phase of the two-leg spin-ladder Cu2(C5N2H12)2Cl4 has been probed through measurements of 1H NMR spectra and 1/T1 in the temperature range 70~mK - 1.2 K. The second order transition line Tc(H) has been determined between Hc1 = 7.52 T and Hc2 = 13 T and varies as (H-Hc1)^(2/3) close to Hc1. From the observation of anomalo

G. Gyorgyi, P. Reimann

A single McCulloch-Pitts neuron, that is, the simple perceptron is studied, with focus on the region beyond storage capacity. It is shown that Parisi&#39;s hierarchical ansatz for the overlap matrix of the synaptic couplings with so called continuous replica symmetry breaking is a solution, and as we propose it is the exact one, to the equilibrium problem. W

W. Gotze, A. P. Singh, Th. Voigtmann

Within the mode-coupling theory (MCT) for the evolution of structural relaxation in glass-forming liquids, correlation functions and susceptibility spectra are calculated characterizing the rotational dynamics of a top-down symmetric dumbbell molecule, consisting of two fused hard spheres immersed in a hard-sphere system. It is found that for sufficiently la

Mariusz Krawiec, Karol I. Wysokinski

The calculation of the charge present in central region of the double barrier structure at non-equilibrium conditions is discussed. We propose here a simple method to calculate non equilibrium Green&#39;s functions which allows consistent calculations of retarded and distribution functions. To illustrate the approach we calculate the charge on the quantum do

Jaume Masoliver, Miquel Montero, Josep M. Porra

High frequency data in finance have led to a deeper understanding on probability distributions of market prices. Several facts seem to be well stablished by empirical evidence. Specifically, probability distributions have the following properties: (i) They are not Gaussian and their center is well adjusted by Levy distributions. (ii) They are long-tailed but

J. Schumacher, J. C. Martinez, F. Martin, M. Maier

In this work we investigate the influence of the use of YSZ and CeO2/YSZ as insulators for Metal- Ferroelectric-Insulator-Semiconductor (MFIS) structures made with SrBi2Ta2O9 (SBT). We show that by using YSZ only the a-axis oriented Pyrochlore phase could be obtained. On the other hand the use of a CeO2/YSZ double-buffer layer gave a c-axis oriented SBT with

F. Ferrari, H. Kleinert, I. Lazzizzera

We set up a Chern-Simons theory for the entanglement of two polymers P_1 and P_2, and calculate the second topological moment <m^2>, where m is the linking number. The result applies approximately to a polymer in an ensemble of many others, if these are considered as a single very long effective polymer.

C. Henrique, G. Batrouni, D. Bideau

We present several numerical results on granular mixtures. In particular, we examine the efficiency of diffusion as a mixing mechanism in these systems. The collisions are inelastic and to compensate the energy loss, we thermalize the grains by adding a random force. Starting with a segregated system, we show that uniform agitation (heating) leads to a unifo

A. Kaminski, Yu. V. Nazarov, L. I. Glazman

We study the Kondo effect in a quantum dot driven out of equilibrium by an external ac field. The Kondo effect can be probed by measuring the dc current induced by an auxiliary dc bias $V_{dc}$ applied across the dot. In the absence of ac perturbation, the corresponding differential conductance $G(V_{dc})$ is known to exhibit a sharp peak at $V_{dc}=0$, whic

David S. Graff, Andrew P. Gould, Nicholas Suntzeff, Robert A. Schommer

We analyze the velocity residuals of 551 carbon stars relative to a rotating-disk model of the inner $\sim 70 \rm deg^2$ of the Large Magellanic Cloud (LMC). We find that the great majority of the stars in this sample are best fit as being due to two different populations, a young disk population containing 20% of the stars with a velocity dispersion of $8 \

J. Robert Buchler, Zoltan Kollath

The Fourier spectral techniques that are common in Astronomy for analyzing periodic or multi-periodic light-curves lose their usefulness when they are applied to unsteady light-curves. We review some of the novel techniques that have been developed for analyzing irregular stellar light or radial velocity variations, and we describe what useful physical and a

Yasushi Suto

We summarize a series of our recent work concerning the cosmological redshift-space distortion and light-cone effects. After briefly describing the theoretical formalism, we show how those effects are sensitive to the cosmological parameters. Then we apply this formalism to predict the two-point correlation functions and power spectra for the X-ray clusters,

Alain Riazuelo, David Langlois

The Cosmic Microwave Background (CMB) anisotropies measurements can provide many clues about the Universe. Although the common belief is that they will allow a very precise measurement of the cosmological parameters (that is, the current state of the Universe), they will alternatively give interesting informations about the state of the initial perturbations

Nick Kaiser, Gillian Wilson, Gerard A. Luppino

We present estimates of the gravitational lensing shear variance obtained from images taken at the CFHT using the UH8K CCD mosaic camera. Six fields were observed for a total of 1 hour each in V and I, resulting in catalogs containing approximately 20,000$ galaxies per field, with properly calibrated and optimally weighted shear estimates. These were average

C. Moss, M. Whittle

We have undertaken a survey of H alpha emission in a substantially complete sample of CGCG galaxies of types Sa and later within 1.5 Abell radii of the centres of 8 low-redshift Abell clusters. Some 320 galaxies were surveyed, of which 116 were detected in emission (39% of spirals, 75% of peculiars). Detected emission was classified as `compact&#39; or `diff

Garik Israelian, Ramon Garcia Lopez, Rafael Rebolo

We discuss the early evolution of beryllium and oxygen in our Galaxy by comparing abundances of these elements for halo and disk metal-poor stars. Both, O and Be rise as we go progressively to more metal-rich stars, showing a slope 0.41 +-0.09 ([Be/O] vs [Fe/H]) for stars with [Fe/H] < -1. This relationship provides an observational constraint to the actuall

Alejandro Gangui

For those angular multipoles where cosmic variance is an issue, non-Gaussianities in the Cosmic Microwave Background (CMB) anisotropies will be hard to detect. Here, we construct explicitly the best unbiased estimator for the CMB angular bispectrum.

M. D. Thornley, N. M. Forster-Schreiber, D. Lutz, R. Genzel

We present new ISO-SWS data for a sample of 27 starburst galaxies, and with these data examine the issues of formation and evolution of the most massive stars in starburst galaxies. Using starburst models which incorporate time evolution, new stellar atmosphere models for massive stars, and a starburst model geometry derived from observations of the prototyp

M. Cocchi, A. Bazzano, L. Natalucci, P. Ubertini

During about 3 years wide field monitoring of the Galactic Center region by the WFC telescopes on board the BeppoSAX satellite, a total of 14 type-I X-ray bursts were detected from the burster 1E 1724-3045 located in the globular cluster Terzan 2. All the observed events showed evidence for photospheric radius expansion due to Eddington-limit burst luminosit

M. Cocchi, A. Bazzano, L. Natalucci, P. Ubertini

We report on the long term monitoring of the GINGA transient source GS 1826-238 performed with the BeppoSAX Wide Fiels Camera (WFC) instrument, during four different observing campaigns covering October 1996 - September 1999. WFC detection of type-I bursting activity from the source ruled out its proposed black hole candidacy and clearly suggested the compac

David R. Alves

The average near-infrared (K-band) luminosity of 238 Hipparcos red clump giants is derived and then used to measure the distance to the Galactic center. These Hipparcos red clump giants have been previously employed as I-band standard candles. The advantage of the K-band is a decreased sensitivity to reddening, and perhaps also a reduced systematic dependenc

R. Osterbart, Y. Balega, T. Bloecker, A. Men&#39;shchikov

We present high-resolution J-, H-, and K-band observations and the first H-K color image of the carbon star IRC +10216. The images were reconstructed from 6m telescope speckle interferograms using the bispectrum speckle interferometry method. The H and K images with resolutions between 70mas and 92mas consist of several compact components within a 0.2&#34; r

Joerg Sanner, Martin Altmann, Jens Brunzendorf, Michael Geffert

We present CCD photometry and proper motion studies of the two open star clusters NGC 1960 (M 36) and NGC 2194. Fitting isochrones to the colour magnitude diagrams, for NGC 1960 we found an age of t=16 Myr and a distance of roughly d=1300 pc and for NGC 2194 t=550 Myr and d=2900 pc, respectively. We combined membership determination by proper motions and sta

Bruno Leibundgut

Type Ia Supernovae are in many aspects still enigmatic objects. Recent years have witnessed a bonanza of supernova observations. The increased samples from dedicated searches have allowed the statistical investigation of Type Ia Supernovae as a class. The observational data on Type Ia Supernovae are very rich, and the uniform picture of a decade ago has been

B. T. Gaensicke, R. E. Fried, H. -J. Hagen, K. Beuermann

We report on follow-up spectroscopy and photometry of the cataclysmic variable candidate HS0907+1902 selected from the Hamburg Quasar Survey. B, V, and R photometry obtained during the first observed outburst of HS0907+1902 (V~13) reveals deep eclipses (DeltaV~2.1-2.8) and an orbital period Porb=4.2h with the eclipse depth decreasing to the red. The outburst

B. W. Fairley, L. R. Jones, C. Scharf, H. Ebeling

We present a measurement of the cluster X-ray luminosity-temperature relation out to high redshift (z~0.8). Combined ROSAT PSPC spectra of 91 galaxy clusters detected in the Wide Angle ROSAT Pointed Survey (WARPS) are simultaneously fit in redshift and luminosity bins. The resulting temperature and luminosity measurements of these bins, which occupy a region

Thomas Beckert

We present self-similar solutions for advection-dominated accretion flows with radial viscous force in the presence of outflows from the accretion flow or infall. The axisymmetric flow is treated in variables integrated over polar sections and the effects of infall and outflows on the accretion flow are parametrised for possible configurations compatible wit

Izumi Hachisu, Mariko Kato, Taichi Kato, Katsura Matsumoto

A theoretical light curve is constructed for the quiescent phase of the recurrent nova U Scorpii in order to resolve the existing distance discrepancy between the outbursts (6 kpc) and the quiescences (14 kpc). Our U Sco model consists of a very massive white dwarf (WD), an accretion disk (ACDK) with a flaring-up rim, and a lobe-filling, slightly evolved, ma

A. Y. Kniazev, S. A. Pustilnik, J. Masegosa, I. Marquez

We present the results of spectrophotometry and BVR CCD photometry, as well as integrated HI radio measurements of a new blue compact galaxy (BCG) HS 0822+3542 with extremely low oxygen abundance: 12+log(O/H) = 7.35, or 1/36 of solar value. The galaxy is the third most metal-deficient BCG after I Zw 18 and SBS 0335-052. Its very high mass fraction of gas (~9