July 2002 arXiv papers — page 19

Torsten Schaub, Kewen Wang

We analyze the problem of defining well-founded semantics for ordered logic programs within a general framework based on alternating fixpoint theory. We start by showing that generalizations of existing answer set approaches to preference are too weak in the setting of well-founded semantics. We then specify some informal yet intuitive criteria and propose a

T. Bench-Capon

This paper introduces the notion of value-based argumentation frameworks, an extension of the standard argumentation frameworks proposed by Dung, which are able toshow how rational decision is possible in cases where arguments derive their force from the social values their acceptance would promote.

J. E. Hirsch

Optical experiments by Molegraaf et al reveal that the superconducting condensation energy of Bi_2Sr_2CaCu_2O_{8+δ} originates in lowering of kinetic energy of the carriers. A perspective on the significance of these results is given.

Tatiana Makarova

We present a collection of experimental evidence on UFOs: Unidentified Ferromagnetic Organic structures. Five types of carbon magnets have been obtained experimentally: 1. Chains of interacting radicals 2. Carbonaceous substances with a mixture of sp2 and sp3 coordinated atoms 3. Amorphous carbon structures containing trivalent elements like P, N. B. 4. Nano

Suzanne M. Fielding

We introduce a driven version of the 1D kinetically constrained spin chain. In its original undriven version, this model shows anomalous coarsening following a quench to a low temperature, with an equilibration time that diverges as exp(1/T^2) for T\to 0. We show that driving of constant rate gamma_dot interrupts coarsening and stabilises the chain in a stat

Ali Najafi, Ramin Golestanian

Dynamics of an array of line defects interacting with a background elastic medium is studied in the linear regime. It is shown that the inertial coupling between the defects and the ambient phonons leads to an anomalous response behavior for the deformation modes of a defect-lattice, in the form of anisotropic and anomalous mass and elastic constants, resona

J. C. Fenton, G. Yang, C. E. Gough

We report four-point IV measurements of the c-axis conductivity of mesa structures of 2212-BSCCO, using a system with sub-microsecond resolution along with multi-level pulses. These allow a test to be made for the presence of nonequilibrium effects. Our results suggest simple heating alone is important in measurements of this kind.

A. Capocci, F. Slanina, Y. -C. Zhang

We introduce a new kind of Information Theory. From a finite number of local, noisy comparisons, we want to design a robust filter such that the outcome is a high ranking number, Both analytical and numerical results are encouraging and we believe our toy model has wide ranging implications in the future Internet-based information selection mechanism.

Gabriel Vasile, Vidar Gudmundsson, Andrei Manolescu

In order to understand the orbital and spin magnetization of a confined electronic system we analyze these ground state properties in the transition from a quantum dot to a quantum ring of finite thickness. The Coulomb interaction between the electrons is treated in the Hartree and Hartree-Fock approximations and special care is taken to include also the con

Alex Hansen, Jean Schmittbuhl

We suggest that the observed large-scale universal roughness of brittle fracture surfaces is due to the fracture process being a correlated percolation process in a self-generated quadratic damage gradient. We use the quasi-static two-dimensional fuse model as a paradigm of a fracture model. We measure for this model, that exhibits a correlated percolation p

L. Turban

Scale-invariant universal crossing probabilities are studied for critical anisotropic systems in two dimensions. For weakly anisotropic standard percolation in a rectangular-shaped system, Cardy's exact formula is generalized using a length-rescaling procedure. For strongly anisotropic systems in 1+1 dimensions, exact results are obtained for the random

A. P. J. Jansen, S. V. Nedea, J. J. Lukkien

We derive analytical expressions for the reactivity of a Single-File System with fast diffusion and adsorption and desorption at one end. If the conversion reaction is fast, then the reactivity depends only very weakly on the system size, and the conversion is about 100%. If the reaction is slow, then the reactivity becomes proportional to the system size, t

David Djajaputra, Bernard R. Cooper

We have performed a systematic first-principles computational study of the effects of impurity atoms (boron, carbon, nitrogen, oxygen, silicon, phosporus, and sulfur) on the orbital hybridization and bonding properties in the intermetallic alloy NiAl using a full-potential linear muffin-tin orbital method. The matrix elements in momentum space were used to c

K. Racka, I. Kuryliszyn, M. Arciszewska, W. Dobrowolski

The Anomalous Hall Effect was investigated in IV-VI ferromagnetic semimagnetic semiconductors of Sn1-xMnxTe codoped with either Eu or Er. The analysis of experimental data: Hall resisitivity and magnetization showed that AHE coefficient RS depends on temperature, its value decreases with the temperature increase. We observe that above ferromagnet-paramagnet

I. Kuryliszyn, T. Wojtowicz, X. Liu, J. K. Furdyna

High- and low-field magneto-transport measurements, as well as SQUID measurements of magnetization, were carried out on Ga1-xMnxAs epilayers grown by low temperature molecular beam epitaxy, and subsequently annealed under various conditions. We observe a large enhancement of ferromagnetism when the samples are annealed at an optimal temperature, typically ab

A. Lavagno

Starting from the basic prescriptions of the Tsallis' nonextensive thermostatistics, i.e. generalized entropy and normalized q-expectation values, we study the relativistic nonextensive thermodynamics and derive a Boltzmann transport equation that implies the validity of the H-theorem where a local nonextensive four-entropy density is considered. Macrosc

H. -J. Stoeckmann

The density of states for a chaotic billiard with randomly distributed point-like scatterers is calculated, doubly averaged over the positions of the impurities and the shape of the billiard. Truncating the billiard Hamiltonian to a N x N matrix, an explicit analytic expression is obtained for the case of broken time-reversal symmetry, depending on rank N of

Debasis Dan, A. M. Jayannavar

We investigate the dynamics of an overdamped Brownian particle moving in a washboard potential with space dependent friction coefficient. Analytical expressions have been obtained for current and diffusion coefficient. We show that the effective diffusion coefficient can be enhanced or suppressed compared to that of the uniform friction case. The diffusion c

S. Kolesnik, B. Dabrowski, J. Mais

ac susceptibility has been studied for polycrystalline Zn$_{1-x}$Mn$_x$O. Stoichiometric samples demonstrate Curie-Weiss behavior, which indicates mostly antiferromagnetic interactions. Magnetic susceptibility can be described by a diluted Heisenberg magnet model developed for semimagnetic semiconductors. High-pressure oxygen annealing induces spin-glass lik

Y. Tanuma, Y. Tanaka, K. Kuroki, S. Kashiwaya

As a probe to determine the pairing symmetry of quasi-two-dimensional anisotropic superconductors, we propose tunneling spectroscopy in the presence of magnetic field, where the magnetic field is parallel to the two dimensional planes and rotated. As a case study, we apply this idea to the models of high-$T_{C}$ cuprates and organic superconductors $κ$-(ET)$

Suzanne M. Fielding, Peter D. Olmsted

We study the early stages of the shear banding instability in semidilute wormlike micelles using the non-local Johnson-Segalman model with a two-fluid coupling of the concentration (phi) to the shear rate (gamma_dot) and micellar strain (tensor{W}). We calculate the ``spinodal'' limit of stability for sweeps along the homogeneous intrinsic flow curve

W. Coburn, W. A. Heindl, R. E. Rothschild, D. E. Gruber

Using a consistent set of models, we parameterized the X-ray spectra of all accreting pulsars in the Rossi X-ray Timing Explorer database which exhibit Cyclotron Resonance Scattering Features (CRSFs, or cyclotron lines). These sources in our sample are Her X-1, 4U 0115+63, Cen X-3, 4U 1626-67, XTE J1946-274, Vela X-1, 4U 1907+09, 4U 1538-52, GX 301-2, and 4U

Kaisa E. Mueller, Yancy L. Shirley, Neal J. Evans, Heather R. Jacobson

Fifty-one dense cores associated with water masers were mapped at 350 micron. These cores are very luminous, 10^3 < Lbol/Lsun < 10^6, indicative of the formation of massive stars. Dust continuum contour maps and photometry are presented for these sources. The spectral energy distributions and normalized radial profiles of dust continuum emission were modeled

Stefanie Komossa, Guenther Hasinger

(Abridged) Cold and warm absorbers have beeen detected in all types of active galaxies (AGN) from low to high redshift. This gas, located in the black hole region of AGN, is thought to play an important role in AGN unification scenarios, in explaining the X-ray background, in black hole growth and AGN evolution. We provide a review of the observations of dus

Patrick B. Hall, Gordon T. Richards, Donald G. York, Charles R. Keeton

The Sloan Digital Sky Survey (SDSS) automatically targeted as a quasar candidate the recently discovered, gravitationally lensed, extremely reddened z=2.2 quasar PMN J0134-0931. The SDSS spectrum exhibits Ca II absorption at z=0.76451, which we identify as the redshift of a lensing galaxy. Hubble Space Telescope imaging shows that components CDE of the syste

G. W. Pratt, M. Arnaud

We present an XMM-Newton observation of A1413, a hot (kT = 6.5 keV) galaxy cluster at z=0.143. We construct gas and temperature profiles up to ~1700 kpc, equivalent to ~0.7 r_200. The gas distribution is well described by a beta model in the outer regions, but is more concentrated in the inner ~250 kpc. We introduce a new parameterisation for the inner regio

P. Papaderos, Y. I. Izotov, T. X. Thuan, K. G. Noeske

(abridged): Using HST and ground-based optical and NIR imaging data, we investigate whether the blue compact dwarf (BCD) galaxy I Zw 18 possesses an extended low-surface-brightness (LSB) old stellar population underlying its star-forming (SF) regions. We show that the exponential intensity decrease observed in the filamentary LSB envelope of the BCD out to 1

M. -A. Miville-Deschenes, G. Lagache, J. -L. Puget

Based on a power spectrum analysis of the IRAS ISSA maps, we present the first detection of the Cosmic far-Infrared Background (CIB) fluctuations at 60 and 100 microns. The power spectrum of 12 low cirrus emission regions is characterized by a power excess at spatial frequencies higher than k~0.02 arcmin^{-1}. Most of this excess is due to noise and to nearb

R. Vio, P. Andreani, L. Tenorio, W. Wamsteker

We provide theoretical procedures and practical recipes to simulate non-Gaussian correlated, homogeneous random fields with prescribed marginal distributions and cross-correlation structure, either in a N-dimensional Cartesian space or on the celestial sphere. We illustrate our methods using far-infrared maps obtained with the Infrared Space Observatory. How

Jorick S. Vink, Alex de Koter

We present radiation-driven wind models for Luminous Blue Variables (LBVs) and predict their mass-loss rates. A comparison between our predictions and the observations of AG Car shows that the variable mass loss behaviour of LBVs is due the recombination/ionisation of Fe IV/III and Fe III/II. We also derive a present-day mass of 35 Msun for AG Car.

Alex de Koter, Jorick S. Vink

We show that the stellar masses implied by our predictions of the wind properties of massive stars are in agreement with masses derived from evolution theory and from direct measurements using spectroscopic binaries, contrary to previous attempts to derive masses from wind theory.

Jens Woitas, Thomas P. Ray, Francesca Bacciotti, Christopher J. Davis

We have observed the bipolar jet from RW Aur A with STIS on board the HST. After continuum subtraction, morphological and kinematic properties of this outflow can be traced to within 0.&#34;1 from the source in forbidden emission lines. The jet appears well collimated, with typical FWHMs of 20 to 30 AU in the first 2&#34; and surprisingly does not show a sep

Oktay H. Guseinov, Efe Yazgan, Sevinc Tagieva, Aybuke Kupce Yoldas

We present the model for determination of pulsar distances or average electron distribution using a method similar to the widely used dependence of A$_V$ on distances in different directions. To have reliable pulsar distances, we have used several natural requirements and distances of pulsar-calibrators. We have constructed dispersion measure-distance relati

Jian-Min Wang, Ruediger Staubert, Luis Ho

We investigate the relationship between accretion rates and the spectral energy distributions (SEDs) of BL Lac objects, using a sample of objects for which published information on the host galaxies, emission-line luminosities, and peak frequencies and luminosities of their SEDs are available. The sample is composed of 43 BL Lac objects which have a relative

Michael Harvanek, John T. Stocke

Radio structure parameters were measured from the highest quality radio maps available for a sample of 3CR radio galaxies in the redshift range 0.15 < z < 0.65. Combined with similar data for quasars in the same redshift range, these morphology data are used in conjunction with a quantification of the richness of the cluster environment around these objects

T. W. Connors, S. Johnston, R. N. Manchester, D. McConnell

We report here on a sequence of 28 observations of the binary pulsar system PSR B1259-63/SS2883 at four radio frequencies made with the Australia Telescope Compact Array around the time of the 2000 periastron passage. Observations made on 2000 Sep 1 show that the pulsar&#39;s apparent rotation measure (RM) reached a maximum of $-14800 \pm 1800$ rad m$^{-2}$,

James E. Taylor, Joseph Silk

We examine the expected signal from annihilation events in realistic cold dark matter halos. If the WIMP is a neutralino, with an annihilation cross-section predicted in minimal SUSY models for the lightest stable relic particle, the central cusps and dense substructure seen in simulated halos may produce a substantial flux of energetic gamma rays. We derive

Makoto Sasaki, Yoichi Asaoka, Masashi Jobashi

We present the cosmic neutrino detecting potential of the Telescope Array for quasihorizontally downward and upward air showers initiated by very high energy neutrinos penetrating the air and the Earth respectively. We adopted model predictions for extraterrestrial neutrino fluxes from active galactic nuclei, gamma-ray bursters, Greisen photo production, the

L. Martinovic

A semiclassical picture of spontaneous symmetry breaking in light front field theory is formulated. It is based on a finite-volume quantization of self-interacting scalar fields obeying antiperiodic boundary conditions. This choice avoids a necessity to solve the zero mode constraint and enables one to define unitary operators which shift scalar field by a c

Hidekazu Yokomakura, Keiichi Kimura, Akira Takamura

We study the CP dependence of neutrino oscillation probability for all channels in arbitrary matter profile within three generations. We show that an oscillation probability for ν_e \to ν_μcan be written in the form P(ν_e \to ν_μ) =A_{eμ} cos δ+ B_{eμ} sin δ+ C_{eμ} without any approximation using the CP phase δ. This result holds not only in constant matter

Samson Abramsky, Bob Coecke

Within the Geometry of Interaction (GoI) paradigm, we present a setting that enables qualitative differences between classical and quantum processes to be explored. The key construction is the physical interpretation/realization of the traced monoidal categories of finite-dimensional vector spaces with tensor product as monoidal structure and of finite sets

David Mateos, Selena Ng, Paul K. Townsend

The AdS/dCFT correspondence is used to show that a planar q-dimensional superconformal CFT defect expands, under the addition of electric charge and angular momentum, to a supersymmetric higher-dimensional defect of geometry R^q x C, where C is an arbitrary curve. The dual string theory process is the expansion of D-branes and fundamental strings into a supe

S. Mereghetti, A. De Luca, P. A. Caraveo, W. Becker

We present the results of an XMM-Newton observation of the radio-quiet X-ray pulsar 1E 1207-5209 located at the center of the shell-like supernova remnant G296.5+10.0. The X-ray spectrum is characterized by the presence of two phase-dependent absorption lines at energies ~0.7 keV and ~1.4 keV. Moreover, these broad spectral features have significant substruc

Chuan-Feng Li, Guang-Can Guo

This paper has been withdrawn by the author(s).The scheme presented is insecure.

E. Widmann, R. S. Hayano, T. Ishikawa, J. Sakaguchi

Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the $(n,L)=(37,35)$ state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure due to the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as pr

L. Lukaszuk

Sum rules for parity violating spin polarizabilities are derived and discussed. They hold both for hadron and nuclear stable targets of arbitrary spin and are exact in strong interactions. Examples of applications to the cases of proton and deuteron targets are given. The legitimacy of the dispersive approach in the Standard Model is discussed.

Olaf Post

We consider a non-compact Riemannian periodic manifold such that the corresponding Laplacian has a spectral gap. By continuously perturbing the periodic metric locally we can prove the existence of eigenvalues in a gap. A lower bound on the number of eigenvalue branches crossing a fixed level is established in terms of a discrete eigenvalue problem. Furtherm

Olaf Post

We investigate spectral properties of the Laplace operator on a class of non-compact Riemannian manifolds. For a given number $N$ we construct periodic (i.e. covering) manifolds such that the essential spectrum of the corresponding Laplacian has at least $N$ open gaps. We use two different methods. First, we construct a periodic manifold starting from an inf

Michael K. Kinyon, J. D. Phillips

In this note we show that the commutant of a Bol loop of odd order is a subloop.

Marc Vanderhaeghen

A short overview is given on how generalized parton distributions (GPDs) enter in a variety of hard exclusive processes such as deeply virtual Compton scattering (DVCS) and hard meson electroproduction reactions on the nucleon. We firstly discuss the links between GPDs and elastic nucleon form factors which represent powerful constraints on parametrizations

Robert Foot

One of the most fascinating ideas coming from particle physics is the concept of mirror matter. Mirror matter is a new form of matter which is predicted to exist if mirror symmetry is respected by nature. At the preset time evidence that mirror matter actually exists is in abundance, coming from a range of observations and experiments in astronomy, particle

J. Bartels, M. G. Ryskin, G. P. Vacca

We estimate the size of the triple Pomeron vertex in perturbative QCD and compare with the phenomenological value extracted from Regge fits to experimental data. For simplicity, the results of the QCD analysis are taken in the large-N_c limit. We find that the perturbative triple Pomeron coupling is of the same order of magnitude as the observed one. We also

Paolo Lipari

The present uncertainties in the knowledge of the neutrino cross sections for E_nu \sim 1 GeV, that is in the energy range most important for atmospheric and long baseline accelerator neutrinos, are large. These uncertainties do not play a significant role in the interpretation of existing data, however they could become a limiting factor in future studies t

B. Dutta, C. S. Kim, Sechul Oh

In light of the recent experimental data from $B$ factories, We try to explain the large branching ratio (compared to the Standard Model prediction) of the decay $B^{\pm}\to η&#39; K^{\pm}$ in the context of R-parity violating ($\rpv$) supersymmetry. We investigate other observed $η^{(\prime)}$ modes and find that only two pairs of $\rpv$ coupling can satisf

C. S. Kim, Jake Lee, Sechul Oh

We study semi-inclusive charmless decays $B \to πX$, where $X$ does not contain a charm (anti)quark. The mode $\bar B^0 \to π^- X$ turns out to be be particularly useful for determination of the CKM matrix element $|V_{ub}|$. We present the branching ratio (BR) of $\bar B^0 \to π^- X$ as a function of $|V_{ub}|$, with an estimation of possible uncertainty. T

M. I. Kotsky, L. N. Lipatov, A. Principe, M. I. Vyazovsky

This paper is devoted to the calculation of the quark-gluon-Reggeized quark effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massive quarks is considered. This vertex has a number of applications, in particular, the result can be used for determination of the next-to-leading correction to the massive Reggeized quark tra

Alexander Bochman

An extension of an abstract argumentation framework, called collective argumentation, is introduced in which the attack relation is defined directly among sets of arguments. The extension turns out to be suitable, in particular, for representing semantics of disjunctive logic programs. Two special kinds of collective argumentation are considered in which the

Alexander Bochman

We address a general representation problem for belief change, and describe two interrelated representations for iterative non-prioritized change: a logical representation in terms of persistent epistemic states, and a constructive representation in terms of flocks of bases.

Alexander Z. Patashinski, Mark A. Ratner

Thermodynamic effects of local structure fluctuations in glassformers are analyzed in terms of energy basins and inter-basin hopping. Depending on the time-scale of measurement, one observes short-time thermodynamic properties related to a narrow set of basins, or equilibrium properties that include structural relaxation. The inter-basin hopping is manifeste

B. I. Belevtsev, V. B. Krasovitsky, A. S. Panfilov, I. N. Chukanova

The magnetic and transport properties of La$_{0.5}$Sr$_{0.5}$CoO$_{3-δ}$ film grown on a LaAlO$_3$ substrate by pulsed-laser deposition are studied. The properties are found to be influenced by a combined influence of the magnetic anisotropy and inhomogeneity. Magnetoresistance anisotropy is determined by the shape anisotropy and the strain-induced magnetic

Seong Gyoon Kim, Won Tae Kim, Toshio Suzuki

We minimized the interface diffuseness in the phase-field models by introducing the parabolic double-well potential and localizing the solute redistribution (or latent heat release) into a narrow region within the phase-field interface. In spite of the parabolic potential with cusps, highly localized solute redistribution and discontinuous diffusivity functi

R. C. Telfer, G. A. Kriss, W. Zheng, A. F. Davidsen

We create stacked composite absorption spectra from Hubble Space Telescope Faint Object Spectrograph data from four quasi-stellar objects to search for absorption lines in the extreme ultraviolet wavelength region associated with LyA forest absorbers in the redshift range 1.6 < z < 2.9. We successfully detect O V 630 in LyA absorbers throughout the 10^13 to

Donald F. Figer

Our Galactic Center hosts over 10% of the known massive stars in the Galaxy. The majority of these stars are located in three particularly massive clusters that formed within the past 5 Myr. While these clusters are extraordinary, their formation repesents about half of the total inferred star formation rate in the Galactic Center. There is mounting evidence

Judith G. Cohen

I am currently analyzing the emission line spectra of the approximately 600 galaxies from the sample of Cohen et al. (2000) and Cohen (2001) in the region of the HDF-North with z<1.5. A progress report on this effort of the Caltech Faint Galaxy Redshift Survey is presented.

Michael S. Turner

Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% +/- 1% baryons; 29% +/- 4% cold dark matter; and 66% +/- 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand i

Dan Maoz

In a recent paper, McLure & Jarvis (2002, astro-ph/0204473, v.1) reanalyze AGN broad-line reverberation measurements presented in Kaspi et al. (2000). They find the broad-line region size and the AGN luminosity at 5100 Ang can be related by R_{BLR} ~ L_{5100}^{0.5}. This differs from the result of Kaspi et al., who found R_{BLR} ~ L_{5100}^{0.7}, a departure

Geoffrey W. Marcy, R. Paul Butler, Debra A. Fischer, Greg Laughlin

We report precise Doppler shift measurements of 55 Cancri (G8V) obtained from 1989 to 2002 at Lick Observatory. The velocities reveal evidence for an outer planetary companion to 55 Cancri orbiting at 5.5 AU. The velocities also confirm a second, inner planet at 0.11 AU. The outer planet is the first extrasolar planet found that orbits near or beyond the orb

Pawel Pietrukowicz

Comparison of the old observations of Cepheids in the Small Magellanic Cloud from the Harvard data archive, with the recent OGLE and ASAS observations allows an estimate of their period changes. All of matched 557 Cepheids are still pulsating in the same mode. One of the Harvard Cepheid, HV 11289, has been tentatively matched to a star which is now apparentl

D. Blaschke, H. Grigorian, G. Poghosyan

Neutron star configurations are considered as thermodynamical systems for which a phase diagram in the angular velocity (Omega) - baryon number (N) plane is obtained with a dividing line N_{crit}(Omega) for quark core configurations. Trajectories of neutron star evolution in this diagram are studied for different scenarios defined by the external torque acti

Jörg Rottler, Mark O. Robbins

Molecular dynamics simulations are used to study a unique expanded jammed state. Tension transforms many glassy polymers from a dense glass to a network of fibrils and voids called a craze. Entanglements between polymers and interchain friction jam the system after a fixed increase in volume. As in dense jammed systems, the distribution of forces is exponent

David Atwood, Alexey A. Petrov

Heavy meson pairs produced in the decays of heavy quarkonium resonances at e+ e- machines (beauty and tau-charm factories) have the useful property that the two mesons are in the CP-correlated states. By tagging one of the mesons as a CP eigenstate, a lifetime difference of heavy neutral meson mass eigenstates width difference may be determined by measuring

S. Ferrara, M. Porrati

We describe the low-energy effective theory of N=1 spontaneously broken supegravity obtained by flux-induced breaking in the presence of n D3 branes. This theory can be obtained by integrating out three massive gravitino multiplets in the hierarchical breaking N=4 to N=3 to N=2 to N=1. This integration also eliminates the IIB complex dilaton. The resulting t

O. K. Vorov, M. S. Hussein, P. Van Isacker

In a k-dimensional system of weakly interacting Bose atoms trapped by a spherically symmetric and harmonic external potential, an exact expression is obtained for the rotating ground states at a fixed angular momentum. The result is valid for arbitrary interactions obeying minimal physical requirements. Depending on the sign of a modified scattering length,

D. M. Gangardt, G. V. Shlyapnikov

We discuss stability and phase coherence of 1D trapped Bose gases and find that inelastic decay processes, such as 3-body recombination, are suppressed in the strongly interacting (Tonks-Girardeau) and intermediate regimes. This is promising for achieving these regimes with a large number of particles. &#34;Fermionization&#34; of the system reduces the phase

Claudio M. G. de Sousa

Considering plane gravitational waves propagating through flat spacetime, it is shown that curvatures experienced both in the starting point and during their arrival at the earth can cause a considerable shift in the frequencies as measured by earth and space-based detectors. Particularly for the case of resonant bar detectors this shift can cause noise-filt

V. K. Dobrev, H. -D. Doebner, R. Twarock

A formulation of quantum mechanics with additive and multiplicative (q-)difference operators instead of differential operators is studied from first principles. Borel-quantisation on smooth configuration spaces is used as guiding quantisation method. After a short discussion this method is translated step-by-step to a framework based on difference operators.

Andrei O. Starinets

We find quasinormal modes of near extremal black branes by solving a singular boundary value problem for the Heun equation. The corresponding eigenvalues determine the dispersion law for the collective excitations in the dual strongly coupled N=4 SYM at finite temperature.

Arkady Kaplan, Boris A. Malomed

A modification of the usual Type-II second-harmonic-generation model is proposed, which includes two additional features: linear conversion and walkoff (group-velocity difference) between two components of the fundamental-frequency (FF) wave. Physical interpretations of the model are possible in both temporal and spatial domains. In the absence of the intrin

Washington Taylor

A general algorithm is presented which gives a closed-form expression for an arbitrary perturbative diagram of cubic string field theory at any loop order. For any diagram, the resulting expression is given by an integral of a function of several infinite matrices, each built from a finite number of blocks containing the Neumann coefficients of Witten&#39;s

G. L. Kane, J. Lykken, Brent D. Nelson, Lian-Tao Wang

We examine arguments that could avoid light superpartners as an implication of supersymmetric radiative electroweak symmetry breaking. We argue that, from the point of view of string theory and standard approaches to generating the mu-term, cancellations among parameters are not a generic feature. While the coefficients relating the Z-mass to parameters in t

S. Moch, P. Uwer, S. Weinzierl

We discuss the calculation of the nf-contributions to the two-loop amplitude for e+ e- -> q qbar g. The calculation uses an efficient method based on nested sums. The result is presented in terms of multiple polylogarithms with simple arguments, which allow for analytic continuation in a straightforward manner.

Antonis Kakas, Loizos Michael

This paper studies the problem of modeling complex domains of actions and change within high-level action description languages. We investigate two main issues of concern: (a) can we represent complex domains that capture together different problems such as ramifications, non-determinism and concurrency of actions, at a high-level, close to the given natural

Javier Rodriguez-Laguna

Real Space Renormalization Group (RSRG) techniques and their applications, mainly to quantum mechanics and to partial differential equations, are discussed. Special emphasis is given to the theoretical insight and the reasons for the success of some techniques, specially DMRG. Applications to the spectrum of dendrimers and excitons on random media are consid

Francesco Giazotto, Kasper Grove-Rasmussen, Rosario Fazio, Fabio Beltram

Highly transmissive ballistic junctions are demonstrated between Nb and the two-dimensional electron gas formed at an InAs/AlSb heterojunction. A reproducible fabrication protocol is presented yielding high critical supercurrent values. Current-voltage characteristics were measured down to 0.4 K and the observed supercurrent behavior was analyzed within a ba

F. Shahbazi, S. Sobhanian, M. Reza Rahimi Tabar, S. Khorram

We investigate the average frequency of positive slope $ν_α^{+} $, crossing the height $α= h- \bar h$ in the surface growing processes. The exact level crossing analysis of the random deposition model and the Kardar-Parisi-Zhang equation in the strong coupling limit before creation of singularities are given.

L. Bahmad, A. Benyoussef, H. Ez-Zahraouy

The magnetic order-disorder layering transitions of a spin-1 Ising model are investigated, under the effect of a variable surface crystal field $Δ_{s}$, using the mean field theory. Each layer $k$, of the film formed with $N$ layers, disorders at a finite surface crystal field distributed according to the law $Δ_k=Δ_s/k^α$, $k=1,2,...,N$ and $α$ being a posi

Mandar M. Deshmukh, D. C. Ralph

By measuring electron tunneling between a ferromagnet and individual energy levels in an aluminum quantum dot, we show how spin-resolved quantum states can be used as filters to determine spin-dependent tunneling rates. We also observe magnetic-field-dependent shifts in the magnet&#39;s electrochemical potential relative to the dot&#39;s energy levels. The s

S. E. Deustua, R. Caldwell, P. Garnavich, L. Hui

We review the current status of cosmological parameters, dark energy and large-scale structure, from a theoretical and observational perspective. We first present the basic cosmological parameters and discuss how they are measured with different observational techniques. We then describe the recent evidence for dark energy from Type Ia supernovae. Dynamical

J. D. Monnier, R. Millan-Gabet

Long-baseline optical interferometers can now detect and resolve hot dust emission thought to arise at the inner edge of circumstellar disks around young stellar objects (YSOs). We argue that the near-infrared sizes being measured are closely related to the radius at which dust is sublimated by the stellar radiation field. We consider how realistic dust opti

R. W. Schmidt, A. C. Fabian, J. S. Sanders

We present temperature and metallicity maps of the Perseus cluster core obtained with the Chandra X-ray Observatory. We find an overall temperature rise from ~3.0 keV in the core to ~5.5 keV at 120 kpc and a metallicity profile that rises slowly from ~0.5 solar to ~0.6 solar inside 60 kpc, but drops to \~0.4 solar at 120 kpc. Spatially resolved spectroscopy

Eckart Janknecht, Robert Baade, Dieter Reimers

Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515-4414 (z_em =1.73, B = 15.0) offers for the first time the opportunity to study the Lyman alpha forest in the redshift range 0.9 < z < 1.7 at a resolution ~ 10 km/s. The number density evolution of the Lyman alpha lines is well described by the power law approach dn/dz = (dn/dz)_0 (1+z)

C. D. Batista

I show that a spontaneous electric polarization is developed in the solution of the Falicov-Kimball model (FKM) by mapping the strong coupling limit of the model into an $xxz$ spin 1/2 model with a magnetic field. In this way, I can determine the phase diagram of the strongly interacting model that shows a transition to a mixed valence regime containing two

K. Tsushima, F. C. Khanna

Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark-meson coupling model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mi

Michael Gutperle

In this short note we compare the endpoint of tachyon condensation of twisted circles with the endpoint of nonpertubative brane nucleation in the Kaluza-Klein Melvin spacetime.

W. A. Sabra

We present a class of magnetically charged brane solutions for the theory of Einstein-Maxwell gravity with a negative cosmological constant in an arbitrary number of spacetime dimensions.

Yasuaki Hikida, Yuji Sugawara

We study the superstring vacua constructed from the conformal field theories of the type H_4 x M, where H_4 denotes the super Nappi-Witten model (super WZW model on the 4-dimensional Heisenberg group H_4) and M denotes an arbitrary N=2 rational superconformal field theory with c=9. We define (type II) superstring vacua with 8 supercharges, which are twice as

J. D. Edelstein, A. Paredes, A. V. Ramallo

We study the gravity dual of several wrapped D-brane configurations in presence of 4-form RR fluxes partially piercing the unwrapped directions. We present a systematic approach to obtain these solutions from those without fluxes. We use D=8 gauged supergravity as a starting point to build up these solutions. The configurations include (smeared) M2-branes at

Marta Volonteri, Francesco Haardt, Piero Madau

We assess models for the assembly of supermassive black holes (SMBHs) at the center of galaxies that trace their hierarchical build-up far up in the dark halo `merger tree&#39;. We assume that the first `seed&#39; black holes (BHs) formed in (mini)halos collapsing at z=20 from high-sigma density fluctuations. As these pregalactic holes become incorporated th

Carolina J. Odman, Alessandro Melchiorri, Michael P. Hobson, Anthony N. Lasenby

The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a class of models based on primordial adiabatic perturbations, cold dark matter and a cosmological constant. In this paper w

Hui Zhao, B. Dal Don, S. Moehl, H. Kalt

We investigate the lateral transport of excitons in ZnSe quantum wells by using time-resolved micro-photoluminescence enhanced by the introduction of a solid immersion lens. The spatial and temporal resolutions are 200 nm and 5 ps, respectively. Strong deviation from classical diffusion is observed up to 400 ps. This feature is attributed to the hot-exciton