January 2004 arXiv papers — page 10

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

In an attempt to increase the number of known microquasars, Paredes et al. (2002) have presented a long-term project focused on the search for new objects of this type. They performed a cross-identification between X-ray and radio catalogs under very restrictive selection criteria for sources with |b|<5 degrees, and obtained a sample of 13 radio-emitting X-r

J. M. Paredes, M. Ribo, J. Marti

Recent studies of relativistic jet sources in the Galaxy, also known as microquasars, have been very useful in trying to understand the accretion/ejection processes that take place near compact objects. However, the number of sources involved in such studies is still small. In an attempt to increase the number of known microquasars we have carried out a sear

W. M. Wood-Vasey, G. Aldering, B. C. Lee, S. Loken

The Nearby Supernova Factory (SNfactory) is an ambitious project to find and study in detail approximately 300 nearby Type Ia supernovae (SNe~Ia) at redshifts 0.03<z<0.08. This program will provide an exceptional data set of well-studied SNe in the nearby smooth Hubble flow that can be used as calibration for the current and future programs designed to use S

Francisco Prada, Anatoly Klypin, J. Flix, M. Martinez

If dark matter (DM), which is considered to constitute most of the mass of galaxies, is made of supersymmetric (SUSY) particles, the centers of galaxies should emit gamma-rays produced by their self-annihilation. We present accurate estimates of continuum gamma-ray fluxes due to neutralino annihilation in the central regions of the Milky Way. We use detailed

J. Flix, M. Martinez, F. Prada

Neutralinos are the natural well-motivated candidates to provide the non-baryonic dark matter of the universe which may produce detectable signals through their annihilation into neutrinos, photons or positrons. Due to its high flux sensitivity and low energy threshold, the MAGIC Cherenkov telescope could potentially detect the neutralino annihilation high e

U. J. Sofia, J. T. Lauroesch, D. M. Meyer, S. I. B. Cartledge

We report interstellar C II column densities or upper limits determined from weak absorption of the 2325.4029 A intersystem transition observed in six translucent sightlines with STIS. The sightlines sample a wide range of interstellar characteristics including total-to-selective extinction, R_{V} = 2.6 - 5.1; average hydrogen density along the sightline, <n

Paola Mazzei

In this review we outline the major points of ab-initio cosmological models focusing on some galaxy evolution unresolved problems. In particular our knowledge of the star formation rate which leads galaxy evolution, i.e. luminosity, colors and dust enrichment, is still very poor. Smoothed particle hydrodynamic simulations including chemo-photometric evolutio

Jun-Hui Zhao, R. M. Herrnstein, G. C. Bower, W. M. Goss

A large radio outburst from Sgr A* was observed during the VLA weekly monitoring program at 2 cm, 1.3 cm and 7 mm, nearly coincident with the brightest X-ray flare detected to date with the XMM-Newton X-ray Observatory on 2002-10-03. The flux density of 1.9$\pm$0.2 Jy measured at 7 mm exceeds the mean value (1.00$\pm$0.01 Jy) by a factor of $\sim 2$, one of

Frazer Pearce

By utilising the inbuilt citation counts from NASA&#39;s astrophysics data system (ADS) I derive how many citations refereed articles receive as a function of time since publication. After five years, one paper in a hundred has accumulated 91 or more citations, a figure which rises to 145 citations after ten years. By adding up the number of citations active

R. G. Sharp, D. Crampton, I. M. Hook, R. G. McMahon

We present the results of a multi-colour (VIZ) survey for low luminosity (M_B<-23.5) quasars with z~5 using the 12K CCD mosaic camera on CFHT. The survey covers 1.8deg^2 to a limiting magnitude of m_z=22.5(Vega), about two magnitudes fainter than the SDSS quasar survey. 20 candidates were selected by their VIZ colours and spectra for 15 of these were obtaine

Avishai Dekel

Recent data, e.g. from SDSS and 2dF, reveal a robust bi-modality in the distribution of galaxy properties, with a characteristic transition scale at stellar mass M_*~3x10^{10} Msun (near L_*), corresponding to virial velocity V~100 km/s. Smaller galaxies tend to be blue disks of young populations. They define a &#34;fundamental line&#34; of decreasing surfac

Melvyn B. Davies, Giampaolo Piotto, Francesca De Angeli

Recent HST observations of a large sample of globular clusters reveal that every cluster contains between 40 and 400 blue stragglers. The population does not correlate with either stellar collision rate (as would be expected if all blue stragglers were formed via collisions) or total mass (as would be expected if all blue stragglers were formed via the unhin

Silvia Zane, Gavin Ramsay, Mario A. Jimenez-Garate, Jan Willem den Herder

We present the results of a series of XMM-Newton EPIC and OM observations of Her X-1, spread over a wide range of the 35 day precession period. We confirm that the spin modulation of the neutron star is weak or absent in the low state - in marked contrast to the main or short-on states. During the states of higher intensity, we observe a substructure in the

Renzo Ramelli, Michele Bianda

Spectro-polarimetric measurements of the D3-HeI 5876 A line profile in 35 prominences have been performed in 2003 with the Gregory-Coudé Telescope in Locarno. Two different experimental techniques (ZIMPOL and Beam-exchange method) have been successfully employed to determine all four Stokes components. Both give compatible results. The preliminary results as

J. E. Smith, A. Robinson, D. M. Alexander, S. Young

We have identified 12 Seyfert 1 galaxies that exhibit optical polarization spectra similar to those of Seyfert 2 galaxies in which polarized broad-lines are detected. We present new spectropolarimetric observations of 3 of them: Was 45, Mrk 231 and NGC 3227. These objects appear to be polarized as a result of far-field scattering in the polar illumination co

C. P. Dullemond, C. Dominik

Isolated Herbig Ae stars can be divided into two groups (Meeus et al. 2001): those with an almost flat spectral energy distribution in the mid-infrared (`group I&#39;), and those with a strong decline towards the far-infrared (`group II&#39;). In this paper we show that the group I vs. II distinction can be understood as arising from flaring vs. self-shadowe

U. Munari, T. Zwitter, E. F. Milone

The expected performance of GAIA satellite on eclipsing binaries is reviewed on the basis of (a) combined Hipparcos and ground-based observations mimicking GAIA data harvest, and (b) accurate simulations using the latest instrument model. It is found that for a large majority of the 16000 SB2 eclipsing binaries that GAIA will discover at magnitudes V<13, the

D. Pourbaix, S. Jancart, A. Jorissen

Among the 120 000 objects in the Hipparcos catalogue, only 235 were fitted with an orbital model. Besides these 235 original astrometric binaries, most Hipparcos entries with a known spectroscopic orbit (extrasolar planet or stellar companion) have now been re-processed, as part of the on-going construction of the 9th Catalogue of Spectroscopic Binary Orbits

Sandro Villanova, Gustavo Baume, Giovanni Carraro, Anna Geminale

We present and discuss broad band CCD $UBV(I)_C$ photometry and low resolution spectroscopy for stars in the region of the open cluster NGC 6996, located in the North America Nebula. The new data allow us to tightly constrain the basic properties of this object. We revise the cluster size, which in the past has been significantly underestimated. The width of

S. M. Saad, J. Kubat, P. Koubsky, P. Harmanec

We present an analysis of new spectroscopic observations of the bright Be star kappa Dra obtained at the Ondrejov observatory during 1992 - 2003 and UBV photometric observations secured at several observatories. The fundamental stellar parameters have been obtained from a comparison with a grid of NLTE model atmospheres. The best fit was found for Teff=14000

M. H. Montgomery, F. Kupka

We present results of a fully non-local model of convection for white dwarf envelopes. We show that this model is able to reproduce the results of numerical simulations for convective efficiencies ranging from very inefficient to moderately efficient; this agreement is made more impressive given that no closure parameters have been adjusted in going from the

G. Chabrier, T. Barman, I. Baraffe, F. Allard

Extending the theory we derived recently for HD209458b to different cases of strongly irradiated gaseous exoplanets, we have calculated the consistent evolution of the new transiting planet, OGLE-TR-56b, for its recently revised mass determination. The theory is shown to successfully reproduce the observed radius, for the proper age of the system. We also ex

Alyssa A. Goodman, Hector G. Arce

Three independent lines of evidence imply that the young star PV Ceph is moving at roughly 20 km/s through the interstellar medium. The first, and strongest, suggestion of motion comes from the geometry of the HH knots in the &#34;giant&#34; Herbig-Haro (HH) flow associated with PV Ceph. Bisectors of lines drawn between pairs of knots at nearly equal distanc

J. Nakashima, S. Deguchi, N. Kuno

IRAS 19312+1950 is an SiO maser source that exhibits a prominent bipolar nebulosity. Mapping observations of this object were made in the CO J=1--0, 13CO J=1--0, C18O J=1--0, CS J=2--1, and HCN J=1--0 lines and in the 150 GHz continuum band. Near-infrared imaging observations were also made in the J, H, and K-bands. The line profiles of the 12CO and HCN spec

Christopher W. Mauche

I provide a review of observations in the optical, UV (HST), and EUV (EUVE and Chandra LETG) of the rapid periodic oscillations of nonmagnetic, disk-accreting, high mass-accretion rate cataclysmic variables (CVs), with particular emphasis on the dwarf nova SS Cyg in outburst. In addition, I drawn attention to a correlation, valid over nearly six orders of ma

Cesar Meirelles Filho, Celso Luiz Lima, Hideaki Miyake

Total and internal energy requirements set constraints on the allowable temperature on the disk. In a gas pressure dominated disk, they lead to a cooling rate that decreases with temperature. These findings are used to show that the flow is mildly supersonic, with the azimuthal Mach number moderately exceeding one in a large extent of the disk. Only in the n

Yukio Tomozawa

A spherically symmetric and static metric that describes physical coordinates is introduced. It is defined to be a metric that gives coordinate independent results for physically observable quantities without a further coordinate transformation. The suggested metric also makes a prediction for the second order gravitational red shift effect that can be utili

S. Ravindranath, H. C. Ferguson, C. Conselice, M. Giavalisco

We examine the evolution of the sizes and number densities of disk galaxies using the high resolution images obtained by the Great Observatories Origins Deep Survey (GOODS) with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). The multiwavelength (B,V,i,z) images allow us to classify galaxies based on their rest-frame B-band morphol

E D Belokolos, V Z Enolskii, M Salerno

Wannier functions of the one dimensional Schroedinger equation with elliptic one gap potentials are explicitly constructed. Properties of these functions are analytically and numerically investigated. In particular we derive an expression for the amplitude of the Wannier function in the origin, a power series expansion valid in the vicinity of the origin and

H. C. Rosu, O. Cornejo-Perez

We show how one can obtain kink solutions of ordinary differential equations with polynomial nonlinearities by an efficient factorization procedure directly related to the factorization of their nonlinear polynomial part. We focus on reaction-diffusion equations in the travelling frame and damped-anharmonic-oscillator equations. We also report an interesting

D. K. Galloway, E. H. Morgan, A. M. Levine

Frequency glitches have been observed so far only in radio pulsars and anomalous X-ray pulsars. Here we present evidence of a glitch in a neutron star accreting from a Be companion. The transient KS 1947+300 reappeared in 2000 October as a moderately strong X-ray source that exhibited 18.7 s pulsations, leading to an identification with the BATSE source GRO

D. J. Croton, E. Gaztanaga, C. M. Baugh, P. Norberg

We measure moments of the galaxy count probability distribution function in the two-degree field galaxy redshift survey (2dFGRS). The survey is divided into volume limited subsamples in order to examine the dependence of the higher order clustering on galaxy luminosity. We demonstrate the hierarchical scaling of the averaged p-point galaxy correlation functi

R. M. Sambruna, J. K. Gambill, L. Maraschi, F. Tavecchio

We present the results from an X-ray and optical survey of a sample of 17 radio jets in AGN performed with Chandra and HST. The sample was selected from the radio and is unbiased toward detection at shorter wavelengths, but preferentially it includes beamed sources. We find that X-ray emission is common on kpc-scales, with over half radio jets exhibiting at

Sen Zhou, Ziqiang Wang

We study the t-J-V model of a doped Mott insulator in connection to high-T_c superconductors. The nearest neighbor Coulomb interaction (V) is treated quantum mechanically on equal footing as the antiferromagnetic exchange interaction (J). Motivated by the SU(2) symmetry at half-filling, we construct a large-N theory which allows a systematic study of the int

George M. Bergman, Saharon Shelah

Let S=Sym(\Omega) be the group of all permutations of a countably infinite set \Omega, and for subgroups G_1, G_2\leq S let us write G_1\approx G_2 if there exists a finite set U\subseteq S such that < G_1\cup U > = < G_2\cup U >. It is shown that the subgroups closed in the function topology on S lie in precisely four equivalence classes under this relation

George M. Bergman

Let S=Sym(\Omega) be the group of all permutations of an infinite set \Omega. Extending an argument of Macpherson and Neumann, it is shown that if U is a generating set for S as a group, respectively as a monoid, then there exists a positive integer n such that every element of S may be written as a group word, respectively a monoid word, of length \leq n in

G. V. Prakash, L. Besombes, T. Kelf, P. N. Bartlett

Micron-scale optical cavities are produced using a combination of template sphere self-assembly and electrochemical growth. Transmission measurements of the tunable microcavities show sharp resonant modes with a Q-factor>300, and 25-fold local enhancement of light intensity. The presence of transverse optical modes confirms the lateral confinement of photons

Tomaz Prosen, Marko Znidaric

We show that the mechanism of quantum freeze of fidelity decay for perturbations with zero time-average, recently discovered for a specific case of integrable dynamics [New J. Phys. 5 (2003) 109], can be generalized to arbitrary quantum dynamics. We work out explicitly the case of chaotic classical counterpart, for which we find semi-classical expressions fo

V. I. Marconi, E. A. Jagla

We present a continuum model for the propagation of cracks and fractures in brittle materials. The components of the strain tensor $ε$ are the fundamental variables. The evolution equations are based on a free energy that reduces to that of linear elasticity for small $ε$, and accounts for cracks through energy saturation at large values of $ε$. We regulariz

R. D&#39;Auria, Sergio Ferrara, M. Trigiante

We show that for all very special quaternionic manifolds a different N=1 reduction exists, defining a Kaehler Geometry which is ``dual&#39;&#39; to the original very special Kaehler geometry with metric G_{a\bar{b}}= - \partial_a \partial_b \ln V (V={1/6}d_{abc}λ^a λ^b λ^c). The dual metric g^{ab}=V^{-2} (G^{-1})^{ab} is Kaehler and it also defines a flat po

M. F. Bode

In this review, I concentrate on describing observations of spatially resolved emission in symbiotic stars at sub-arcsecond scales. In some of the closer objects, the highest resolutions discussed here correspond to linear dimensions similar to the supposed binary separation. A total of 17 stars well accepted as symbiotics are now observed to show sub-arcsec

Andreas Bredthauer, Ulf Lindstrom, Jonas Persson, Linus Wulff

We solve the tensionless string in a constant plane wave background and obtain a hugely degenerate spectrum. This is the case for a large class of plane wave backgrounds. We show that the solution can also be derived as a consistent limit of the quantized tensile theory of IIB strings in a pp-wave. This is in contrast to the situation for several other backg

Masafumi Fukuma, Yuji Kono, Akitsugu Miwa

We show that a certain class of short-distance cutoff can give rise to large suppression on the CMB anisotropies at large angular scales.

F. Calura, F. Matteucci

By means of detailed chemo-photometric models for elliptical, spiral and irregular galaxies, we evaluate the cosmic history of the production of chemical elements as well as the metal mass density of the present-day universe. We then calculate the mean metal abundances for galaxies of different morphological types, along with the average metallicity of galac

Gopal-Krishna, Peter L. Biermann, Paul J. Wiita

Although the possibility of a low energy cut-off (LEC) of the relativistic electron population (E_{min} ~ 0.1 GeV) in the different components of radio galaxies has been discussed in the literature, from both theoretical and observational viewpoints, its possible role in causing a distinct spectral flattening, and thus reducing the apparent brightness temper

T. Schaefer, V. Zetocha

Motivated by measurements of the flavor singlet axial coupling constant of the nucleon in polarized deep inelastic scattering we study the contribution of instantons to OZI violation in the axial-vector channel. We consider, in particular, the f_1-a_1 meson splitting, the flavor singlet and triplet axial coupling of a constituent quark, and the axial couplin

Dieter Lust

In this review we describe the general geometrical framework of brane world constructions in orientifolds of type IIA string theory with D6-branes wrapping 3-cycles in a Calabi-Yau 3-fold. These branes generically intersect in points on the internal space, and the patterns of intersections govern the chiral fermion spectra. We discuss how the open string spe

Rodolfo Russo, Alessandro Tanzini

The aim of this report is to give an overview of the duality between type IIB string theory on the maximally supersymmetric PP-wave and the BMN sector of N=4 Super Yang-Mills theory. The general features of the string and the field theory descriptions are reviewed, but the main focus of this report is on the comparison between the two sides of the duality. I

Durmus A. Demir

That the scalar field theories with no dimensional couplings possess local scale invariance (LSI) via the curvature gauging is utilized to show that the Goldstone boson, released by the spontaneous LSI breakdown, is swallowed by the spacetime curvature in order to generate Newton&#39;s constant in the same spirit as the induction of vector boson masses via s

Mohsen Shadmehri

A self-similar solution for time evolution of quasi-spherical, self-gravitating accretion flows is obtained under the assumption that the generated heat by viscosity is retained in the flow. The solutions are parameterized by the ratio of the mass of the accreting gas to the central object mass and the viscosity coefficient. While the density and the pressur

A. Vidal-Madjar, J. -M. Désert, A. Lecavelier des Etangs, G. Hébrard

Four transits of the planet orbiting the star HD209458 were observed with the STIS spectrograph on board HST. The wavelength domain (1180-1710A) includes HI as well as CI, CII, CIV, NV, OI, SI, SiII, SiIII and SiIV lines. During the transits, absorptions are detected in HI, OI and CII (5+/-2%, 13+/-4.5% and 7.5+/-3.5%, respectively). No absorptions are detec

S. K. Yi, E. Peng, H. Ford, S. Kaviraj

We present the results of our analysis of the photometric data of globular clusters in the elliptical galaxy NGC 5128 (Cen A). We show that the integrated colour U-B can be an effective metallicity indicator for simple stellar populations. This is because it is sensitive to metallicity via the opacity effect but relatively insensitive to the effective main s

G. S. Agarwal, G. O. Ariunbold, J. von Zanthier, H. Walther

We discuss a simple search problem which can be pursued with different methods, either on a classical or on a quantum basis. The system is represented by a chain of trapped ions. The ion to be searched is a member of that chain, consists, however, of an isotopic species different to the others. It is shown that the classical imaging may lead as fast to the f

G. O. Ariunbold, G. S. Agarwal, Z. Wang, H. Walther

Motivated by recent experiments on photon statistics from individual dye pairs planted on biomolecules and coupled by fluorescence resonance energy transfer (FRET), we show here that the FRET dynamics can be modelled by Gaussian random processes with colored noise. Using Monte-Carlo numerical simulations, the photon intensity correlations from the FRET pairs

Dennis D. Dietrich, Lester L. Hirst

Expressions for the absorption spectrum of a nucleus in a three- and a two-dimensional crystal respectively are obtained analytically at zero and at finite temperature respectively. It is found that for finite temperature in two dimensions the Moessbauer effect vanishes but is replaced by what we call a Quasi-Moessbauer effect. Possibilities to identify two-

Banibrata Mukhopadhyay

Propagation of fermions in curved space-time generates a gravitational interaction due to the coupling between spin of the fermion and space-time curvature. This gravitational interaction, which is an axial-vector appears as the CPT violating term in the Lagrangian, can generate the neutrino asymmetry in Universe. If the back-ground metric is spherically asy

Nicolas Laflorencie, Didier Poilblanc

The role of various magnetic inter-chain couplings has been investigated recently by numerical methods in doped frustrated quantum spin chains. A non-magnetic dopant introduced in a gapped spin chain releases a free spin-1/2 soliton. The formation of a local magnetic moment has been analyzed in term of soliton confinement. A four-spin coupling which might or

Satoshi Fujimoto

We analyze an asymptotically exact solution for the transition temperature of p-wave superconductivity near ferromagnetic criticality on the basis of the three-dimensional electron systems in which scattering processes are dominated by exchange interactions with small momentum transfers. Taking into account all Feynman diagrams in the gap equation, we show t

Catalin D. Spataru, Lorin X. Benedict, Steven G. Louie

We present ab initio quasiparticle self-energy calculations in crystalline GaAs for cases of intense electronic excitation (~ 10% of valence electrons excited into conduction band), relevant for high-intensity ultra-short pulsed laser experiments. Calculations are performed using an out-of-equilibrium generalization of the GW approximation based on the Keldy

V. I. Yukalov, K. -P. Marzlin, E. P. Yukalova

Trapped Bose atoms cooled down to temperatures below the Bose-Einstein condensation temperature are considered. Stationary solutions to the Gross-Pitaevskii equation (GPE) define the topological coherent modes, representing nonground-state Bose-Einstein condensates. These modes can be generated by means of alternating fields whose frequencies are in resonanc

David Goldberg

We show that principal series representations of the real split odd orthogonal group have non-vanishing rank one bessel models of a very particular type.

A. Kuzmich, T. A. B. Kennedy

The entanglement of multi-atom quantum states is considered. In order to cancel noise due to inhomogeneous light atom coupling, the concept of matched multi-atom observables is proposed. As a means to eliminate an important form of decoherence this idea should be of broad relevance for quantum information processing with atomic ensembles. The general approac

Nevena Ilieva, Heide Narnhofer, Walter Thirring

We investigate simple examples of supersymmetry algebras with real and Grassmann parameters. Special attention is payed to the finite supertransformations and their probability interpretation. Furthermore we look for combinations of bosons and fermions which are invariant under supertransformations. These combinations correspond to states that are highly ent

V. B. Bezerra, G. L. Klimchitskaya, V. M. Mostepanenko, C. Romero

We give a rigorous analytical derivation of low-temperature behavior of the Casimir entropy in the framework of the Lifshitz formula combined with the Drude dielectric function. An earlier result that the Casimir entropy at zero temperature is not equal to zero and depends on the parameters of the system is confirmed, i.e. the third law of thermodynamics (th

J. P. Barjaktarevic, G. J. Milburn, Ross H. McKenzie

We demonstrate a method of exploring the quantum critical point of the Ising universality class using unitary maps that have recently been demonstrated in ion trap quantum gates. We reverse the idea with which Feynman conceived quantum computing, and ask whether a realisable simulation corresponds to a physical system. We proceed to show that a specific simu

Hiroshi Fujisaki

A nonadiabatic-transition system which exhibits ``quantum chaotic&#39;&#39; behavior [Phys. Rev. E {\bf 63}, 066221 (2001)] is investigated from quasi-classical aspects. Since such a system does not have a naive classical limit, we take the mapping approach by Stock and Thoss [Phys. Rev. Lett. {\bf 78}, 578 (1997)] to represent the quasi-classical dynamics o

F. Benatti, V. Cappellini, M. De Cock, M. Fannes

Two non-commutative dynamical entropies are studied in connection with the classical limit. For systems with a strongly chaotic classical limit, the Kolmogorov-Sinai invariant is recovered on time scales that are logarithmic in the quantisation parameter. The model of the quantised hyperbolic automorphisms of the 2-torus is examined in detail.

John Proos, Christof Zalka

We show in some detail how to implement Shor&#39;s efficient quantum algorithm for discrete logarithms for the particular case of elliptic curve groups. It turns out that for this problem a smaller quantum computer can solve problems further beyond current computing than for integer factorisation. A 160 bit elliptic curve cryptographic key could be broken on

S. Bumble

Theoretical physics is used for a toy model of molecular biology to assess conditions that lead to the edge of chaos (EOC) in a network of biomolecules. Results can enhance our ability to understand complex diseases and their treatment or cure.

Hideo Hasegawa

Effects of distractions such as noises and parameter heterogeneity have been studied on the firing activity of ensemble neurons, each of which is described by the extended Morris-Lecar model showing the graded persisting firings with the aid of an included ${\rm Ca}^{2+}$-dependent cation current. Although the sustained activity of {\it single} neurons is ra

Lorin Swint Matthews, T. W. Hyde

A numerical model with broad applications to complex (dusty) plasmas is presented. The self-consistent N-body code allows simulation of the coagulation of fractal aggregates, including the charge-dipole interaction of the clusters due to the spatial arrangement of charge on the aggregate. It is shown that not only does a population of oppositely charged part

Susan Z. Hua, Harsh Deep Chopra

In the present study, a prototypical reaction in biochemistry involving a well-known bio-molecule called imidazole (C3H4N2) and its known affinity towards transition metals (such as Co, Ni, Cu, Fe, etc.) has been used to illustrate and exemplify the use of ballistic conductors as probes for molecular reactions at the quantum level. Atomic point contacts of t

J. Sapirstein

High accuracy helium wave functions based on exponentials with random coefficients are transformed into momentum space. The utility of the wave functions is demonstrated through calculation of the expectation value of various operators needed to evaluate relativistic and QED corrections.

Jeremy Butterfield

This paper is about the metaphysical debate whether objects persist over time by the selfsame object existing at different times (nowadays called `endurance&#39; by metaphysicians), or by different temporal parts, or stages, existing at different times (called ` perdurance&#39;). I aim to illuminate the debate by using some elementary kinematics and real ana

Jean-Marc Sparenberg, Byron Jennings

Two types of one-body functions extracted from microscpic models of the 8B ground state are compared with one another and with a potential-model wave function. The one-body overlap function seems to have the strongest physical meaning.

W. D. Ramsay

I start by reviewing existing $\vec{p}p$ measurements with particular emphasis on the recent 221 MeV $\vec{p}p$ measurement at TRIUMF which permitted the weak meson-nucleon coupling constants $h^{pp}_ρ$ and $h^{pp}_ω$ to be determined separately for the first time. I then review $\vec{n}p$ experiments, with specific details of the $\vec{n}p \to dγ$ experimen

R. Reifarth, R. C. Haight, M. Heil, F. Kaeppeler

Neutron capture cross sections of unstable isotopes are important for neutron induced nucleosynthesis as well as for technological applications. The Rare Isotope Accelerator (RIA) or comparable facilities will be able to produce radioactive ion beams up to 10**12 particles/s and would therefore be a suitable place for (n,g) studies on radioactive isotopes wi

C. Anteneodo, A. M. Batista, R. L. Viana

We investigate the synchronization phenomenon in coupled chaotic map lattices where the couplings decay with distance following a power-law. Depending on the lattice size, the coupling strength and the range of the interactions, complete chaos synchronization may be attained. The synchronization domain in parameter space can be analytically delimited by mean

Fatihcan M. Atay

Networks of weakly nonlinear oscillators are considered with diffusive and time-delayed coupling. Averaging theory is used to determine parameter ranges for which the network experiences amplitude death, whereby oscillations are quenched and the equilibrium solution has a large domain of attraction. The amplitude death is shown to be a common phenomenon, whi

Ioana Bena, Avinash Khare, Avadh Saxena

We obtain the exact nontopological soliton lattice solutions of the Associated Lamé equation in different parameter regimes and compute the corresponding energy for each of these solutions. We show that in specific limits these solutions give rise to nontopological (pulse-like) single solitons, as well as to different types of topological (kink-like) single

Anna De Simone, Mirko Navara, Pavel Pták

In this note we collect several observations on state extensions. They may be instrumental to anyone who pursues the theory of quantum logics. In particular, we find out when extensions (resp. signed extensions) exist in the &#34;concrete&#34; concrete logic of all even-element subsets of an even-element set. We also mildly add to the study of difference-clo

Alberto Corso, Craig Huneke, Daniel Katz, Wolmer Vasconcelos

This article outgrew from an effort to understand our basic question: Are the annihilators of the non-zero Koszul homology modules $H_i$ of an unmixed ideal $I$ contained in the integral closure $\bar{I}$ of $I$? We also obtain some variations on a result of Burch, which continue the theme of the paper in that they deal with annihilators of homology and inte

B. Zilber

The paper is an extended version of the talk in the Logic Colloquium-2000 at Paris. We discuss a series of results and problems around Hrushovski&#39;s construction of counter-examples to the Trichotomy conjecture.

B. Zilber

We study the universal cover of the complex one-dimensional torus as a model-theoretic structure in a natural language. We consider also abstract covers of one-dimensional tori over algebraically closed fields of characteristic zero. The main result states that the structures can be described uniquely up to isomorphism by a simple (non-first order) sentence,

Ilia Krasikov

We use Turan type inequalities to give new non-asymptotic bounds on the extreme zeros of orthogonal polynomials in terms of the coefficients of their three term recurrence. Most of our results deal with symmetric polynomials satisfying the three term recurrence $p_{k+1}=x p_k-c_k p_{k-1},$ with a nondecreasing sequence $\{c_k\}$. As a special case they inclu

Kendra Nelsen, Arun Ram

Generalized Hall-Littlewood polynomials (Macdonald spherical functions) and generalized Kostka-Foulkes polynomials ($q$-weight multiplicities) arise in many places in combinatorics, representation theory, geometry, and mathematical physics. This paper attempts to organize the different definitions of these objects and prove the fundamental combinatorial resu

Jorge Cortes, Sonia Martinez, Francesco Bullo

This paper presents coordination algorithms for groups of mobile agents performing deployment and coverage tasks. As an important modeling constraint, we assume that each mobile agent has a limited sensing/communication radius. Based on the geometry of Voronoi partitions and proximity graphs, we analyze a class of aggregate objective functions and propose co

Adrian Andrada, Isabel Dotti

In this paper we give a procedure to construct hypersymplectic structures on $R^{4n}$ beginning with affine-symplectic data on $R^{2n}$. These structures are shown to be invariant by a 3-step nilpotent double Lie group and the resulting metrics are complete and not necessarily flat. Explicit examples of this construction are exhibited.

Yonatan Bilu, Nati Linial

We consider {\em monotone} embeddings of a finite metric space into low dimensional normed space. That is, embeddings that respect the order among the distances in the original space. Our main interest is in embeddings into Euclidean spaces. We observe that any metric on $n$ points can be embedded into $l_2^n$, while, (in a sense to be made precise later), f

Alessio Pomponio

In this paper we study the existence of solutions and their concentration phenomena of a singularly perturbed semilinear Schrodinger equation with the presence of the critical Sobolev exponent.

N. Ishii

Let E be an elliptic curve with complex multiplication by R, where R is an order of discriminant D<-4 of an imaginary quadratic field K . If a prime number p is decomposed completely in the ring class field associated with R, then E has good reduction at a prime ideal P of K dividing p and there exist positive integers u and v such that 4p=u^2-Dv^2. It is we

Michael Hitrik

For a class of non-selfadjoint semiclassical operators in dimension one, we get a complete asymptotic description of all eigenvalues near a critical value of the leading symbol of the operator on the boundary of the pseudospectrum.

David Goldberg

We examine the reducibility of induced from discrete series representations of $SU_n$ over a $p$--adic field of characteristic zero. Some results are given for groups sharing derived group. We give a relationship between the $R$-groups for $U)n$ and $SU_n.$ Nonabelian $R$-groups are discussed. Elliptic representations are examined and in the generic case we

Roberto Fernandez, Gregory Maillard

We introduce an statistical mechanical formalism for the study of discrete-time stochastic processes with which we prove: (i) General properties of extremal chains, including triviality on the tail $σ$-algebra, short-range correlations, realization via infinite-volume limits and ergodicity. (ii) Two new sufficient conditions for the uniqueness of the consist

Roberto Fernandez, Gregory Maillard

We discuss the relationship between discrete-time processes (chains) and one-dimensional Gibbs measures. We consider finite-alphabet (finite-spin) systems, possibly with a grammar (exclusion rule). We establish conditions for a stochastic process to define a Gibbs measure and vice versa. Our conditions generalize well known equivalence results between ergodi

Josep M. Pons, Pere Talavera

We discuss the mechanism of truncations driven by the imposition of constraints. We show how the consistency of such truncations is controlled, and give general theorems that establish conditions for the correct uplifting of solutions. We show in some particular examples how one can get correct upliftings from 7d supergravities to 10d type IIB supergravity,

Thibault Damour

After recalling the definition of black holes, and reviewing their energetics and their classical thermodynamics, one expounds the conjecture of Bekenstein, attributing an entropy to black holes, and the calculation by Hawking of the semi-classical radiation spectrum of a black hole, involving a thermal (Planckian) factor. One then discusses the attempts to

Olaf Lechtenfeld

I explain how to construct noncommutative BPS configurations in four and lower dimensions by solving linear matrix equations. Examples are instantons in D=4 Yang-Mills, monopoles in D=3 Yang-Mills-Higgs, and (moving) solitons in D=2+1 Yang-Mills-Higgs. Some emphasis is on the latter as a showcase for the dressing method.

F. Girelli, T. Krajewski, P. Martinetti

This paper aims at presenting the first steps towards a formulation of the Exact Renormalization Group Equation in the Hopf algebra setting of Connes and Kreimer. It mostly deals with some algebraic preliminaries allowing to formulate perturbative renormalization within the theory of differential equations. The relation between renormalization, formulated as

Alfred Scharff Goldhaber, Anton Rebhan, Peter van Nieuwenhuizen, Robert Wimmer

We review some recent developments in the subject of quantum corrections to soliton mass and central charge. We consider in particular approaches which use local densities for these corrections, as first discussed by Hidenaga Yamagishi. We then consider dimensional regularization of the supersymmetric kink in 1+1 dimensions and an extension of this method to