November 2003 arXiv papers — page 2

The NA49 Collaboration, T. Anticic

Production of Lambda and Antilambda hyperons was measured in central Pb-Pb collisions at 40, 80, and 158 A$\cdot$GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The $Λ/π$ ratio at mid-rapidity and in full phase space shows a pronounced maximum between the highest AGS and 40 A$\cdot$GeV S

Holger F. Hofmann

It is shown that coherent superpositions of two oppositely polarized n-photon states can be created by post-selecting the transmission of n independently generated photons into a single mode transmission line. It is thus possible to generate highly non-classical n-photon polarization states using only the bunching effects associated with the bosonic nature o

H. L. Haroutyunyan, G. Nienhuis

The relative phase between two uncoupled BE condensates tends to attain a specific value when the phase is measured. This can be done by observing their decay products in interference. We discuss exactly solvable models for this process in cases where competing observation channels drive the phases to different sets of values. We treat the case of two modes

Tarun Biswas

The transition from microscopic to macroscopic in quantum mechanics can be seen from various points of view. It is often not merely a transition from quantum to classical mechanics in the sense of the Correspondence Principle. The fact that real macroscopic objects like baseballs are composites of an extremely large number of microscopic particles (electrons

F. Spineanu, M. Vlad, K. Itoh, S. -I. Itoh

We propose a new phenomenology of the generation of internal transport barriers, based on the exact periodic solution of the Flierl-Petvishvili equation. We examine the stability of this solution and compare the late stages of the flow with the ensemble of vortices.

Cyriaque Genet, Erwin Altewischer, Martin P. van Exter, J. P. Woerdman

We present a symmetry-based theory of the depolarization induced by subwavelength metal hole arrays. We derive the Mueller matrices of hole arrays with various symmetries (in particular square and hexagonal) when illuminated by a finite-diameter (e.g. gaussian) beam. The depolarization is due to a combination of two factors: (i) propagation of surface plasmo

D. K. Gramotnev, T. A. Nieminen

This paper analyses theoretically and numerically the effect of varying grating amplitude on the extremely asymmetrical scattering (EAS) of bulk and guided optical modes in non-uniform strip-like periodic Bragg arrays with stepwise and gradual variations in the grating amplitude across the array. A recently developed new approach based on allowance for the d

G. Orlandini

This talk contains a short review of some of the progresses made in the last three years in the calculations of electromagnetic cross sections of light nuclei up to A=7. Since many of them have been possible thanks to the use of the Lorentz Integral Transform (LIT) method, both for inclusive and exclusive reactions, I will first make a few remarks on the met

Victor D. Efros, Winfried Leidemann, Giuseppina Orlandini, Edward L. Tomusiak

Trinucleon longitudinal response functions R_L(q,omega) are calculated for q values up to 500 MeV/c. These are the first calculations beyond the threshold region in which both three-nucleon (3N) and Coulomb forces are fully included. We employ two realistic NN potentials (configuration space BonnA, AV18) and two 3N potentials (UrbanaIX, Tucson-Melbourne). Co

J. L. Egido, L. M. Robledo

The degrees of freedom associated with shape fluctuations and space orientation of atomic nuclei are analyzed with effective forces and large configuration spaces. A pedagogical theoretical introduction to the topic of symmetries restoration broken in the mean field approach as well as to the concept of generator coordinate is presented. We discuss global pr

J. L. Egido, L. M. Robledo, R. R. Rodriguez-Guzman

The shape coexistence in the nuclei $^{182-192}$Pb is analyzed within the Hartree-Fock-Bogoliubov approach with the effective Gogny force. A good agreement with the experimental energies is found for the coexisting spherical, oblate and prolate states. Contrary to the established interpretation, it is found that the low-lying prolate and oblate $0^+$ states

R. R. Rodriguez-Guzman, J. L. Egido, L. M. Robledo

The superdeformed band of $^{36}$Ar is studied with the Gogny force D1S and the angular momentum projected generator coordinate method for the quadrupole moment. The band head excitation energy, moments of inertia, $B(E2)$ transition probabilities and stability against quadrupole fluctuations at low spin are studied. The Self Consistent Cranking method is al

E. N. E. van Dalen, A. E. L. Dieperink

The contribution from hyperons to the bulk viscosity of neutron star matter is calculated. Compared to previous works we use for the weak interaction the one-pion exchange model rather than a current-current interaction, and include the neutral current $nn \leftrightarrow nΛ$ process. Also the sensitivity to details of the equation of state is examined. Comp

Abdelwaheb Charfi, Salah Horchani

We propose a model of "Fundamental Symmetries" leading to a dynamical origin of mass, based on the concept of "Historical Time" and described by a relativistic Schrodinger-type equation. In this framework, the matter spectrum is obtained by excitation, at the level of internal structure, of a fundamental system composed of two constituents, t

R G Shandil, Jagjit Singh

Howard's conjecture, which states that in the linear instability problem of inviscid heterogeneous parallel shear flow growth rate of an arbitrary unstable wave must approach zero as the wave length decreases to zero, is established in a mathematically rigorous fashion for plane parallel heterogeneous shear flows with negligible buoyancy force $gβ\ll 1$

Uwe Nagel, Roberto Notari, Maria Luisa Spreafico

We study families of ropes of any codimension that are supported on lines. In particular, this includes all non-reduced curves of degree two. We construct suitable smooth parameter spaces and conclude that all ropes of fixed degree and genus lie in the same component of the corresponding Hilbert scheme. We show that this component is generically smooth if th

Nadia Chiarli, Silvio Greco, Uwe Nagel]

This note is an attempt to relate explicitly the geometric and algebraic properties of a space curve that is contained in some double plane. We show in particular that the minimal generators of the homogeneous ideal of such a curve can be written in a very specific form. As applications we characterize the possible Hartshorne-Rao modules of curves in a doubl

Uwe Nagel

Castelnuovo-Mumford regularity and any extended degree function can be thought of as complexity measures for the structure of finitely generated graded modules. A recent result of Doering, Gunston, Vasconcelos shows that both can be compared in case of a graded algebra. We extend this result to modules and analyze when the estimate is in fact an equality. A

Alina Vdovina

Let $X$ be a compact Riemann surface of genus $\geq 2$ of constant negative curvature -1. An extremal disk is an embedded (resp. covering) disk of maximal (resp. minimal) radius. A surface containing an extremal disk is an {\em extremal surface}. This paper gives formulas enumerating extremal surfaces of genus $\geq 4$ up to isometry. We show also that the i

Carlos T. Simpson

For a standard path of connections going to a generic point at infinity in the moduli space $M_{DR}$ of connections on a compact Riemann surface, we show that the Laplace transform of the family of monodromy matrices has an analytic continuation with locally finite branching. In particular the convex subset representing the exponential growth rate of the mon

Shouchuan Zhang

The relations between the radical of crossed product $R #_σH$ and algebra $R$ are obtained. Using this theory, the author shows that if $H$ is a finite-dimensional semisimple, cosemisimle, and either commutative or cocommutative Hopf algebra, then $R$ is $H$-semiprime iff $R$ is semiprime iff $R#_σH$ is semiprime.

Niels Grønbæk

Let B be a unital Banach algebra. A projection in B which is equivalent to the identitity may give rise to a matrix-like structure on any two-sided ideal A in B. In this set-up we prove a theorem to the effect that the bounded Hochschild cohomology H^n(A,A^*) vanishes for all n>=1. The hypothesis of this theorem involve (i) strong H-unitality of A, (ii) a gr

Niels Grønbæk

A Banach algebra A is self-induced if the multiplication is an isomorphism from the A-balanced projective tensor-square of A to A. The class of self-induced Banach algebras is a natural generalization of unital Banach algebras, providing a fertile framework for developing homological aspects of unital Banach algebras. Elementary results with applictions to c

Ganesh C Gorain, Sujit K Bose

Here we are concerned about uniform stability of damped nonlinear transverse vibrations of an elastic string fixed at its two ends. The vibrations governed by nonlinear integro-differential equation of Kirchoff type, is shown to possess energy uniformly bounded by exponentially decaying function of time. The result is achieved by considering an energy-like L

Niels Grønbæk

We investigate weak amenability of the Banach algebra A(X) of approximable operators on a Banach space X and its relation to factorization properties of operators in A(X). We show that if A(X) is weakly amenable, then either A(X) is self-induced (a nice factorization property), or X is very special, combining some of the exotic properties of the spaces of Go

S. Buyalo, V. Schroeder

We show that for each n\ge 2 there is a quasi-isometric embedding of the hyperbolic space H^n in the product T^n=Tx...xT of n copies of a (simplicial) metric tree T. On the other hand, we prove that there is no quasi-isometric embedding H^2 --> TxR^m for any metric tree T and any m\ge 0.

Liu Lanzhe

In this paper, we obtain the continuity for some multilinear operators related to certain non-convolution operators on the Triebel--Lizorkin space. The operators include Littlewood--Paley operator and Marcinkiewicz operator.

Shouchuan Zhang

The characterization of $H$-prime radical is given in many ways. Meantime, the relations between the radical of smash product $R # H$ and the $H$-radical of Hopf module algebra $R$ are obtained.

Shouchuan Zhang

T. Shudo and H. Miyamito \cite{SM78} showed that $C$ can be decomposed into a direct sum of its indecomposable subcoalgebras of $C$. Y.H. Xu \cite {XF92} showed that the decomposition was unique. He also showed that $M$ can uniquely be decomposed into a direct sum of the weak-closed indecomposable subcomodules of $M$(we call the decomposition the weak-closed

Shouchuan Zhang

We obtain that the global dimensions of $R$ and the crossed product $R # _σH$ are the same; meantime, their weak dimensions are also the same, when $H$ is finite-dimensional semisimple and cosemisimple Hopf algebra.

Shouchuan Zhang

We construct the $H$-von Neumann regular radical for $H$-module algebras and show that it is an $H$-radical property. We obtain that the Jacobson radical of twisted graded algebra is a graded ideal. For twisted $H$-module algebra $R$, we also show that $r_{j}(R#_σH)= r_{Hj}(R)#_σH$ and the Jacobson radical of $R$ is stable, when $k$ is an algebraically close

Shouchuan Zhang

It is shown that all strongly symmetric elements are solutions of constant classical Yang-Baxter equation in Lie algebra, or of quantum Yang-Baxter equation in algebra. Otherwise, all solutions of constant classical Yang-Baxter equation (CYBE) in Lie algebra $L$ with dim $L \le 3$ over field $k$ of characteristic 2 are obtained

Shouchuan Zhang

All solutions of constant classical Yang-Baxter equation (CYBE) in Lie algebra $L$ with dim $L \le 3$ are obtained and the sufficient and necessary conditions which $(L, \hbox {[ ]}, Δ_r, r)$ is a coboundary (or triangular) Lie bialgebra are given. The strongly symmetric elements in $L\otimes L $ are found and they all are solutions of CYBE in $L$ with $dim

Aleksandar Ivić

Sums of squares of $|ζ(1/2+it)|$ over short intervals are investigated. Known upper bounds for the fourth and twelfth moment of $|ζ(1/2+it)|$ are derived. A discussion concerning other possibilities for the estimation of higher power moments of $|ζ(1/2+it)|$ is given.

YoungAe Han

This proposal relates to the design, analysis and application of a novel numerical scheme for the solution of axisymmetric scattering problems. To this end, a procedure is introduced to iteratively evaluate the solution of the Lippmann-Schwinger integral equation in $O(N\log^2 N)$ operations, where $N$ is the number of the discretization points. The method a

Q. Feng, T. Jech, J. Zapletal

We isolate several classes of stationary sets of kappa^omega and investigate implications among them. Under a large cardinal assumption, we prove a structure theorem for stationary sets.

Y. Nikolayevsky

A Riemannian manifold is called IP, if the eigenvalues of its skew-symmetric curvature operator are pointwise constant. It was previously shown that for all n\ge 4, except n=7, any IP manifold either has constant curvature, or is a warped product, with some specific function, of a line and a space of constant curvature. We extend this result to the case n =

D. Kaledin

This is a write-up of my talk at the Conference on algebraic structures in Montreal, July 2003. I try to give a brief informal introduction to the proof of Y. Ruan's conjecture on orbifold cohomology multiplication for symplectic quotient singularities given in V. Ginzburg and D. Kaledin, math.AG/0212279. Version 2: minor changes, added some references.

B. Enriquez, P. Etingof

We construct some classes of dynamical $r$-matrices over a nonabelian base, and quantize some of them by constructing dynamical (pseudo)twists in the sense of Xu. This way, we obtain quantizations of $r$-matrices obtained in earlier work of the second author with Schiffmann and Varchenko. A part of our construction may be viewed as a generalization of the Do

Wadim Zudilin

The idea to use classical hypergeometric series and, in particular, well-poised hypergeometric series in diophantine problems of the values of the polylogarithms has led to several novelties in number theory and neighbouring areas of mathematics. Here we present a systematic approach to derive second-order polynomial recursions for approximations to some val

P. Gibilisco, T. Isola

Hasegawa and Petz introduced the notion of dual statistically monotone metrics. They also gave a characterisation theorem showing that Wigner-Yanase-Dyson metrics are the only members of the dual family. In this paper we show that the characterisation theorem holds true under more general hypotheses.

Mian Wang

Recent observations confirm that our universe is flat and consists of a dark energy component $Ω_{DE}\simeq 0.7$. This dark energy is responsible for the cosmic acceleration as well as determines the feature of future evolution of the universe. In this paper, we discuss the dark energy of universe in the framework of scalar-tensor cosmology. It is shown that

Alexey A. Petrov

We review recent developments in charm physics, focusing on the physics of charmed mesons. We discuss charm spectroscopy, decay constants, as well as searches for new physics with charmed mesons. We discuss D0-anti-D0 mixing and CP-violation in charm decays. We also present the modified Nelson plot of charm mixing predictions.

J. P. B. C. de Melo, T. Frederico, E. Pace, G. Salme`

The pion electromagnetic form factor is calculated in the space- and time-like regions from -10 $(GeV/c)^2$ up to 10 $(GeV/c)^2$, within a front-form model. The dressed photon vertex where a photon decays in a quark-antiquark pair is depicted generalizing the vector meson dominance ansatz, by means of the vector meson vertex functions. An important feature o

S. Dalley, B. van de Sande

We review recent progress of field theory on a transverse lattice including: realistic calculations of pion structure in large-N_c QCD; fermion doubling and chiral symmetry; a new strong coupling limit; supersymmetry on the transverse lattice; lightcone zero-mode analysis.

S. Eidelman, L. Lukaszuk

New precise data on the low energy electron-positron annihilation into hadrons from Novosibirsk are used to obtain bounds on the elasticity parameter and the difference between the phase of the pion form factor and that of pion pion scattering

E. Perez

Searches for R-parity violating supersymmetry performed at the H1 experiment are presented. Emphasis is put on searches for squarks, which may be resonantly produced at the HERA $ep$ collider in supersymmetry where R-parity is violated. The preliminary results presented here were obtained using data collected at a centre-of-mass energy of 320 GeV and corresp

M. K. Suleymanov, O. B. Abdinnov, N. S. Angelov, B. Z. Belashev

The experimental results on some centrality depending characteristics of hadron-nuclear and nuclear-nuclear interactions at high energies demonstrate the regime changes. Appearance of strong interaction matter's mixed states is considered as a cause of it and the effect of a cluster formation is discussed as one of the phenomena connected with the mixed

T. L. Boyadjiev, P. P. Fiziev

In this paper the static, spherically symmetric and electrically charged black hole solutions in Einstein-Born-Infeld gravity with massive dilaton are investigated numerically. The Continuous Analog of Newton Method (CANM) is used to solve the corresponding nonlinear multipoint boundary value problems (BVPs). The linearized BVPs are solved numerically by mea

Yuri N. Obukhov

There is a number of completely integrable gravity theories in two dimensions. We study the metric-affine approach on a 2-dimensional spacetime and display a new integrable model. Its properties are described and compared with the known results of Poincare gauge gravity.

Robert D. Klauber

The persistent, second order, anomalous signal found in the Brillet and Hall experiment is derived by applying 4D differential geometry in the rotating earth frame. By incorporating the off diagonal time-space components of the rotating frame metric directly into the analysis, rather than arbitrarily transforming them away, one finds a signal dependence on t

Douglas A. Galbi

The history of the occupations "author" and "photographer" provides an insightful perspective on copyright and creativity. The concept of the romantic author, associated with personal creative genius, gained prominence in the eighteenth century. However, in the U.S. in 1900 only about three thousand persons professed their occupation to be &#

Dima Grigoriev

Let $\{w_{i,j}\}_{1\leq i\leq n, 1\leq j\leq s} \subset L_m=F(X_1,...,X_m)[{\partial \over \partial X_1},..., {\partial \over \partial X_m}]$ be linear partial differential operators of orders with respect to ${\partial \over \partial X_1},..., {\partial \over \partial X_m}$ at most $d$. We prove an upper bound n(4m^2d\min\{n,s\})^{4^{m-t-1}(2(m-t))} on the

Amar Isli

We consider the integration of existing cone-shaped and projection-based calculi of cardinal direction relations, well-known in QSR. The more general, integrating language we consider is based on convex constraints of the qualitative form $r(x,y)$, $r$ being a cone-shaped or projection-based cardinal direction atomic relation, or of the quantitative form $(α

Max Voskob, Nuck Punin

The public sector comprises government agencies, ministries, education institutions, health providers and other types of government, commercial and not-for-profit organisations. Unlike commercial enterprises, this environment is highly heterogeneous in all aspects. This forms a complex network which is not always optimised. A lack of optimisation and communi

C. R. da Silva, U. L. Fulco, M. L. Lyra, G. M. Viswanathan

In this work, we study the critical behavior of an epidemic propagation model that considers individuals that can develop drug resistance. In our lattice model, each site can be found in one of four states: empty, healthy, normally infected (not drug resistant) and strain infected (drug resistant) states. The most relevant parameters in our model are related

V. C. Aguilera-Navarro, M. Fortes, M. de Llano, F. J. Sevilla

We recall the fundamental fact that Cooper pairs defined without ignoring two- hole pairs along with two-particle ones leads to a purely imaginary pair energy when the problem is based on the ideal Fermi gas sea. However, bound finite- lifetime pairs are recovered when it is based on the BCS ground-state Fermi sea. Their excitation energy is gapped at zero t

S. Kobe

Exact ground states are calculated for the Sherrington-Kirkpatrick (SK) spin-glass containing up to N=90 spins. A ground-state energy per spin $e^{\infty}_0 = - 0.7637 \pm 0.0004$ is found from the $N$ dependence of the misfit parameter, which is a measure of frustration of the system. The results are compared with those of two related models, which can be i

Natalya A. Zimbovskaya

Within a quasiclassical transport theory for 2D electron system we analyze a recently observed effect of microwave rectification at the boundary between two 2D metals of different carrier densities. Nonlinear response is employed to explain the effect. It is shown that the effect of rectification arises due to inhomogeneity of the electron density which brea

Clément Daniel, Laura M. Herz, Carlos Silva, Freek J. M. Hoeben

We present femtosecond transient absorption measurements on $π$-conjugated supramolecular assemblies in a high pump fluence regime. Oligo(\emph{p}-phenylenevinylene) monofunctionalized with ureido-\emph{s}-triazine (MOPV) self-assembles into chiral stacks in dodecane solution below 75$^{\circ}$C at a concentration of $4\times 10^{-4}$ M. We observe exciton b

V. Ballenegger, J. P. Hansen

The strengths and short-comings of the point-dipole model for polar fluids of spherical molecules are illustrated by considering the physically more relevant case of extended dipoles formed by two opposite charges $\pm q$ separated by a distance $d$ (dipole moment $μ=q d$). Extensive Molecular Dynamics simulations on a high density dipolar fluid are used to

Aranya B. Bhattacherjee, E. Courtade, E. Arimondo

We investigate the possibility of inducing a bosonic current which is rotational in a pseudo 1D quasi-condensate confined in an optical toroidal trap. The stability of such a current is also analyzed using hydrodynamics approach. We find that such a current is uniform when the circular symmetry is preserved and energetically stable when the modes of elementa

R. A. Duine, B. W. A. Leurs, H. T. C. Stoof

We study the dynamics of a straight vortex line in a partially Bose-Einstein condensed atomic gas. Using a variational approach to the stochastic field equation that describes the dynamics of the condensate at nonzero temperature, we derive the stochastic equations of motion for the position of the vortex core. Using these results, we calculate the time it t

G. Sheet, S. Mukhopadhyay, P. Raychaudhuri

The point contact spectrum between a normal metal and a superconductor often shows unexpected sharp dips in the conductance at voltage values larger than the superconducting energy gap. These dips are not predicted in the Blonder-Tinkham-Klapwizk (BTK) theory, commonly used to analyse these contacts. We present here a systematic study of these dips in a vari

Andrew N. Jordan, Markus Buttiker

We show how many-body ground state entanglement information may be extracted from sub-system energy measurements at zero temperature. Generically, the larger the measured energy fluctuations are, the larger the entanglement is. Examples are given with the two-state system and the harmonic oscillator. Comparisons made with recent qubit experiments show this t

James P. Gleeson

A new model for stock price fluctuations is proposed, based upon an analogy with the motion of tracers in Gaussian random fields, as used in turbulent dispersion models and in studies of transport in dynamically disordered media. Analytical and numerical results for this model in a special limiting case of a single-scale field show characteristics similar to

B. Gao, A. Komnik, R. Egger, D. C. Glattli

Experimental and theoretical results for transport through crossed metallic single-wall nanotubes are presented. We observe a zero-bias anomaly in one tube which is suppressed by a current flowing through the other nanotube. The phenomenon is shown to be consistent with the picture of strongly correlated electrons within the Luttinger liquid model. The most

G. Medeiros-Ribeiro, E. Ribeiro, H. Westfahl

The knowledge of electron and hole g-factors, their control and engineering are key for the usage of the spin degree of freedom for information processing in solid state systems. The electronic g-factor will be materials dependent, the effect being larger for materials with large spin-orbit coupling. Since electrons can be individually trapped into quantum d

A S Arnold

We theoretically investigate an adjustable-radius magnetic storage ring for laser-cooled and Bose-condensed atoms. Additionally, we discuss a novel time-dependent variant of this and other ring traps. Time-orbiting ring traps provide a high optical access method for spin-flip loss prevention near a storage ring's circular magnetic field zero. Our scalabl

J. Marciak-Kozlowska, M. Kozlowski

In this paper the superheating of electron plasma by femtosecond laser pulses is investigated. With Heaviside thermal equation (Lasers in Engineering, 12, (2002), p.17) the generation of superhot electrons is described. It is shown that in hot electron plasma (i.e. with electron energies >5MeV) the thermal shock waves can be generated. Key words: Femtosecond

R. Grochowski, P. Walzel, M. Rouijaa, C. A. Kruelle

Experimental results are presented on the transport properties of granular materials on a vibratory conveyor. For circular oscillations of the shaking trough a non-monotonous dependence of the transport velocity on the normalized acceleration is observed. Two maxima are separated by a regime, where the granular flow is much slower and, in a certain driving r

F. P. Mancini, P. Sodano, A. Trombettoni

We review the self-consistent mean-field theory for charge-frustrated Josephson junction arrays. Using <cos(ϕ)> (ϕis the phase of the superconducting wavefunction) as order parameter and imposing the self-consistency condition, we compute the phase boundary line between the superconducting region (<cos(ϕ)> not equal to zero) and the insulating one (<cos(ϕ)>

E. Räsänen, A. Harju, M. J. Puska, R. M. Nieminen

We use density-functional methods to study the effects of an external magnetic field on two-dimensional quantum dots with a rectangular hard-wall confining potential. The increasing magnetic field leads to spin polarization and formation of a highly inhomogeneous maximum-density droplet at the predicted magnetic field strength. At higher fields, we find an o

L. M. Jonsson, T. Nord, S. Viefers, J. M. Kinaret

We have performed a theoretical analysis of the operational characteristics of a carbon-nanotube-based three-terminal nanorelay. We show that short range and van der Waals forces have a significant impact on the characteristics of the relay and introduce design constraints. We also investigate the effects of dissipation due to phonon excitation in the drain

Mauro S. Ferreira, Stefano Sanvito

Motivated by the possibility of combining spintronics with molecular structures, we investigate the conditions for the appearance of spin-polarization in low-dimensional tubular systems by contacting them to a magnetic substrate. We derive a set of general expressions describing the charge transfer between the tube and the substrate and the relative energy c

Lionel Bureau, Liliane Leger

We study the friction of a poly(dimethylsiloxane) (PDMS) rubber network sliding, at low velocity, on a substrate on which PDMS chains are end-tethered. We thus clearly evidence the contribution to friction of the pull-out mechanism of chain-ends that penetrate into the network. This interfacial dissipative process is systematically investigated by probing th

D. I. Khomskii, U. Löw

In many transition metal compounds, in particular those containing Fe^{2+} and Co^{3+}, there occur spin-state transitions between low-spin and high-spin (or intermediate-spin) states. We show that typical interactions between similar spin-state ions are short-range repulsion, and long-range interaction which can have different sign depending on the elastic

Liliya L. R. Williams, Arif Babul, Julianne J. Dalcanton

Although high-resolution N-body simulations make robust empirical predictions for the density distribution within cold dark matter halos, these studies have yielded little physical insight into the origins of the distribution. We investigate the problem using analytic and semi-analytic approaches. Simple analytic considerations suggest that the inner slope o

Christian Marinoni, Federico Piazza

In a previous paper we have proposed a non--Newtonian, phenomenological description of the effective gravitational force acting between exotic dark matter and baryons, which was shown to fit well the kinematics in the inner regions of low surface brightness, gas--rich galaxies. The Gravitational Suppression (GraS) scheme is, admittedly, an ad-hoc model; it d

W. C. Keel

I present two-band HST STIS imaging, and WIYN spectral mapping, of ongoing mass transfer in the interacting galaxy pair NGC 1409/10 (where NGC 1410 is the Seyfert galaxy also catalogued as III Zw 55). Archival snapshot WFPC2 imaging from the survey by Malkan et al. showed a dust feature stretching between the galaxies, apparently being captured by NGC 1409.

V. Charmandaris, E. Le Floc&#39;h, I. F. Mirabel

We present evidence for the dramatically different morphology between the rest frame UV and 7micron mid-IR emission of VV114 and Arp299, two nearby (z~0) violently interacting infrared luminous galaxies (LIRGs). Nearly all LIRGs are interacting systems and it is currently accepted that they dominate the IR emission at z>1. Luminous IR galaxies located at z=1

James E. Taylor, Arif Babul, Joseph Silk

We describe our recent attempts to model substructure in dark matter halos down to very small masses, using a semi-analytic model of halo formation. The results suggest that numerical simulations of halo formation may still be missing substructure in the central regions of halos due to purely numerical effects. If confirmed, this central &#39;overmerging&#39

C. Barraud, the HETE-2 team

FREGATE, the gamma-ray detector of HETE-2 is entirely dedicated to the study of GRBs. Its main characteristic is its broad energy range, from 7 keV to 400 keV. This energy range can be further extended down to 2 keV using the data from the WXM, the X-ray detector of HETE-2. Such a large energy range allows to study in details the prompt emission of GRBs, det

M. Jura

When a main sequence star evolves into a red giant and its Kuiper Belt Object&#39;s (KBO&#39;s) reach a temperature of about 170 K, the dust released during the rapid ice-sublimation of these cometary bodies may lead to a detectable infrared excess at 25 microns, depending upon the mass of the KBO&#39;s. Analysis of IRAS data for 66 first ascent red giants w

Trilce Estrada-Piedra, Juan Pablo Torres-Papaqui, Roberto Terlevich, Olac Fuentes

We present a new technique to segregate old and young stellar populations in galactic spectra using machine learning methods. We used an ensemble of classifiers, each classifier in the ensemble specializes in young or old populations and was trained with locally weighted regression and tested using ten-fold cross-validation. Since the relevant information co

Sebastien C. Vauclair, Alain Blanchard, the XMM-Omega project collaboration

The evolution of the temperature distribution function (TDF) of X-ray clusters is kn own to be a powerful cosmological test of the density parameter of the Universe. Recent XMM observations allows us to measure accurately the L - T relation of high redshift X-ray clusters. In order to investigate cosmological implication of this recent results, we have deriv

M. Takami, A. Chrysostomou, T. P. Ray, C. Davis

We detect near-infrared H2 emission in DG Tau using the Infrared Camera and Spectrograph (IRCS) on the 8.2-m SUBARU telescope. The spectra obtained along the jet axis show that the centroidal position of the 1-0 S(1) emission is offset by 0.2&#34; from the star towards the jet, while those obtained perpendicular to the jet axis show a marginal extension, ind

A. Natta, L. Testi, R. Neri, D. S. Shepherd

We present observations of six isolated, pre-main-sequence, intermediate mass stars selected for shallow spectra at submillimeter wavelengths at 1.3, 2.6, 7.0, and 36 millimeters from the IRAM PdBI and the VLA. We analyze the new observations of these stars (HD34282, HD35187, HD142666, HD143006, HD150193, HD163296) together with similar observations of three

Jonathan Ferreira

In the current paradigm of star formation magnetic fields play a very central role. Indeed, they probably help or even channel the initial gravitational collapse of the parent molecular cloud. But their most spectacular effect is certainly the production of ubiquitous, powerful, bipolar self-collimated jets. Also, in the last decade, evidence has come that i

Jonathan Ferreira

In this lecture I review the theory of magnetized accretion discs driving jets, with a focus on Young Stellar Objects (YSOs). I first introduce observational and theoretical arguments in favor of the ``disc wind&#39;&#39; paradigm. There, accretion and ejection are interdependent, requiring therefore to revisit the standard picture of accretion discs. A simp

Frederic Daigne, Jose A. Font

We present results from a comprehensive number of relativistic, time-dependent, axisymmetric simulations of the runaway instability of non-constant angular momentum thick discs around black holes. This second paper extends earlier results where only constant angular momentum discs were considered. All relevant aspects of the theory of stationary thick discs

F. A. van Broekhuizen, J. V. Keane, W. A. Schutte

The 4.62 micron absorption band, observed along the line-of-sight towards various young stellar objects, is generally used as a qualitative indicator for energetic processing of interstellar ice mantles. This interpretation is based on the excellent fit with OCN-, which is readily formed by ultraviolet (UV) or ion-irradiation of ices containing H2O, CO and N

I. Marquez, F. Durret, J. Masegosa, M. Moles

We present the kinematical data obtained for a sample of active (Seyfert) and non active isolated spiral galaxies, based on long slit spectra along several position angles in the Halpha line region and, in some cases, in the Ca triplet region as well. Gas velocity distributions are presented, together with a simple circular rotation model that allows to dete

S. L. Lumsden, D. M. Alexander, J. H. Hough

We present new spectropolarimetry of a sample of nearby Compton-thin Seyfert 2 galaxies (ie those with N_H<10^23 cm^-2). We show that the detection rate of scattered broad Halpha in this sample is considerably higher than in Seyfert 2 galaxies as a whole. Our results also show that in this low obscuration set it is possible to find scattered broad Halpha eve

Stuart P. D. Gill, Alexander Knebe, Brad K. Gibson

We present preliminary results from a series of high-resolution N-body simulations that focus on 8 dark matter halos each of order a million particles within the virial radius. We follow the time evolution of hundreds of individually tracked satellite galaxies and relate their physical properties to the differing halo environmental conditions. Our main scien

Jaron Kurk, Andrea Cimatti, Sperello di Serego Alighieri, Joel Vernet

We are carrying out a search for Lyman alpha emitting galaxies at z = 6.5 employing slitless spectroscopy at the VLT. In our 43 square arcminute field we find three isolated single emission lines with SEDs consistent with line emitting galaxies at z = 6.5.

Alexandre Girouard

Using Morse theory and a new relative homological linking of pairs, we prove a ``homological linking principle&#39;&#39;, thereby generalizing many well known results in critical point theory.

Philipp Treutlein, Peter Hommelhoff, Tilo Steinmetz, Theodor W. Hänsch

We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $5-130 μ$m from the microchip surface. The coherence lifetime in the chip trap is independent of atom-surface distance within our measurement accuracy, and agrees well with the results

Luis P. Chimento

We investigate a flat Friedmann-Robertson-Walker spacetime filled with k-essence and find the set of functions F which generate three different families of extended tachyon fields and Chaplygin gases. They lead to accelerated and superaccelerated expanding scenarios. For any function F, we find the first integral of the k-field equation when the k-field is d

Martin Kruczenski, David Mateos, Robert C. Myers, David J. Winters

We study N_f D6-brane probes in the supergravity background dual to N_c D4-branes compactified on a circle with supersymmetry-breaking boundary conditions. In the limit in which the resulting Kaluza--Klein modes decouple, the gauge theory reduces to non-supersymmetric, four-dimensional QCD with N_c colours and N_f << N_c flavours. As expected, this decouplin