October 2006 arXiv papers — page 29

George Rupp, Eef van Beveren

The narrow $D_{s0}^{\ast}$(2317) and broad $D_0^{\ast}$(2300-2400) charmed scalar mesons and their radial excitations are described in a coupled-channel quark model that also reproduces the properties of the light scalar nonet. All two-meson channels containing ground-state pseudoscalars and vectors are included. The parameters are chosen fixed at published

S. V. Goloskokov

We analyse spin effects in diffractive vector meson leptoproduction at small $x$ on the basis of the generalized parton distribution (GPD) approach. We take into account quark transverse degrees of freedom in the hard subprocess. We calculate amplitudes for the longitudinally and transversely polarized photons and vector mesons. Our results on the cross sect

Abdelhak Djouadi, Gregory Moreau, Francois Richard

It is notorious that, contrary to all other precision electroweak data, the forward-backward asymmetry for b quarks $A_{FB}^b$ measured in Z decays at LEP1 is nearly three standard deviations away from the predicted value in the Standard Model; significant deviations also occur in measurements of the asymmetry off the Z pole. We show that these discrepancies

Brian Aa. Petersen

We report on several studies of charm baryon production and decays by the BaBar collaboration. We confirm previous observations of the $Ξ_c^{'0/+}$, $Ξ_c(2980)^+$ and $Ξ_c(3077)^+$ baryons, measure branching ratios for Cabibbo-suppressed $Λ_c^+$ decays and use baryon decays to study the properties of the light-quark baryons, $Ω^-$ and $Ξ(1690)^0$.

CDF Collaboration

Using 355 pb^-1 of data collected by the CDF II detector in \ppbar collisions at sqrt{s} = 1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B -> D pi and B -> D pi pi pi. We present the first measurement of the ratio of branching fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) = 1.05 pm 0.10 (stat) pm 0.22 (syst). We

Cristinel Diaconu, CPP Marseille, DESY

Events with isolated leptons and missing transverse momentum are searched for in electron- or positron-proton collisions at HERA by the H1 and ZEUS experiments. Such events may be explained within the Standard Model by W boson production, followed by leptonic decay. The analysis performed including HERA I and the recently collected data at HERA II results in

Harry I. Ringermacher, Lawrence R. Mead

We derive the phenomenological Milgrom square-law acceleration, describing the apparent behavior of dark matter, as the reaction to the Big Bang from a model based on the Lorentz-Dirac equation of motion traditionally describing radiation reaction in electromagnetism but proven applicable to expansion reaction in cosmology. The model is applied within the Ro

Dirk Puetzfeld

We report on a package of routines for the computer algebra system Maple which supports the explicit determination of the geometric quantities, field equations, equations of motion, and conserved quantities of General Relativity in the post-Newtonian approximation. The package structure is modular and allows for an easy modification by the user. The set of r

Gamal G. L. Nashed, Mohamed M. Mourad

We give an exact solution to the gravitational field in the new general relativity. The solution creates Bonnor spacetime. This spacetime describes the gravitational field of a stationary beam of light. The energy and momentum of this solution is calculated using the energy-momentum complex given by Møller in (1978) within the framework of the Weitzenb{\rm $

Zhao Ren, Li Huaifan, Zhang Shengli

Taking the horizon surface of the black hole as a compact membrane and solving the oscillation equation of this membrane by Klein-Gordon equation, we derive the frequencies of oscillation modes of the horizon surface, which are proportional to the radiation temperature of the black hole. However, the frequencies of oscillation modes are not equidistant. Usin

Joseph Y. Halpern, Yoram Moses

We show how solution concepts in games such as Nash equilibrium, correlated equilibrium, rationalizability, and sequential equilibrium can be given a uniform definition in terms of \emph{knowledge-based programs}. Intuitively, all solution concepts are implementations of two knowledge-based programs, one appropriate for games represented in normal form, the

Sandrine Blazy, Frédéric Gervais, Régine Laleau

This paper describes an approach for reusing specification patterns. Specification patterns are design patterns that are expressed in a formal specification language. Reusing a specification pattern means instantiating it or composing it with other specification patterns. Three levels of composition are defined: juxtaposition, composition with inter-patterns

Sandrine Blazy

Program comprehension is the most tedious and time consuming task of software maintenance, an important phase of the software life cycle. This is particularly true while maintaining scientific application programs that have been written in Fortran for decades and that are still vital in various domains even though more modern languages are used to implement

Omer Giménez

We show that solving planning domains on binary variables with polytree causal graph is \NP-complete. This is in contrast to a polynomial-time algorithm of Domshlak and Brafman that solves these planning domains for polytree causal graphs of bounded indegree.

Angela S. Mellish, Niels Kjaergaard, Paul S. Julienne, Andrew C. Wilson

We describe a new implementation of magnetic collider for investigating cold collisions between ultracold atomic clouds in different spin states, and we use this to investigate scattering involving both even and odd order partial waves. Our method relies on the axial assymetry of a double-well magnetic trap to selectively prepare the spin state in each cloud

M. K. Dalai, P. Pal, B. R. Sekhar, N. L. Saini

We have investigated the temperature-dependent changes in the near-$E$$_F$ occupied and unoccupied states of Pr$_{0.67}$Ca$_{0.33}$MnO$_3$ which shows the presence of ferromagnetic and antiferromagnetic phases. The temperature-dependent changes in the charge and orbital degrees of freedom and associated changes in the Mn 3$d$ - O 2$p$ hybridization result in

W. Jiang, J. Huang, Y. Wang, M. Laradji

We analyzed extensively the dynamics of polymer chains in solutions simulated with dissipative particle dynamics (DPD), with a special focus on the potential influence of a low Schmidt number of a typical DPD fluid on the simulated polymer dynamics. It has been argued that a low Schmidt number in a DPD fluid can lead to underdevelopment of the hydrodynamic i

J. A. Millan, W. Jiang, M. Laradji, Y. Wang

Polymer solutions subject to pressure driven flow and in nanoscale slit pores are systematically investigated using the dissipative particle dynamics approach. We investigated the effect of molecular weight, polymer concentration and flow rate on the profiles across the channel of the fluid and polymer velocities, polymers density, and the three components o

R. Seguin, A. Schliwa, S. Rodt, K. Pötschke

A systematic variation of the exciton fine-structure splitting with quantum dot size in single InAs/GaAs quantum dots grown by metal-organic chemical vapor deposition is observed. The splitting increases from -80 to as much as 520 $μ$eV with quantum dot size. A change of sign is reported for small quantum dots. Model calculations within the framework of eigh

A. Corsi, A. Milchev, V. G. Rostiashvili, T. A. Vilgis

We propose a simple scaling theory describing the variation of the mean first passage time (MFPT) $τ(N,M)$ of a regular block copolymer of chain length $N$ and block size $M$ which is dragged through a selective liquid-liquid interface by an external field $B$. The theory predicts a non-Arrhenian $τ$ vs. $B$ relationship which depends strongly on the size of

J. J. Alonso, J. F. Fernandez

We study anisotropic antiferromagnetic one-layer films with dipolar and nearest-neighbor exchange interactions. We obtain a unified phase diagram as a function of effective uniaxial D_e and quadrupolar C anisotropy constants. We study in some detail how spins reorient continuously below a temperature T_s as T and D_e vary.

Iacopo Carusotto, Michiel Wouters, Cristiano Ciuti

Some recent results concerning nonlinear optics in semiconductor microcavities are reviewed from the point of view of the many-body physics of an interacting photon gas. Analogies with systems of cold atoms at thermal equilibrium are drawn, and the peculiar behaviours due to the non-equilibrium regime pointed out. The richness of the predicted behaviours sho

Christoph Lemell, Andres Arnau, Joachim Burgdörfer

Projected momentum distributions of electrons, i.e. Compton profiles above the topmost atomic layer have recently become experimentally accessible by kinetic electron emission in grazing-incidence scattering of atoms at atomically flat single crystal metal surfaces. Sub-threshold emission by slow projectiles was shown to be sensitive to high-momentum compone

CM Roland, R Casalini

Structural relaxation times and viscosities for non-associated liquids and polymers are a unique function of the product of temperature, T, times specific volume, V, with the latter raised to a constant, g_tau. Similarly, for both neat o-terphenyl (OTP) and a mixture the entropy for different T and pressures, P, collapse to a single curve when expressed vers

Kenichi Hachitani, Hideaki Amanuma, Hideto Fukazawa, Yoh Kohori

The 31P-NMR (nuclear magnetic resonance) measurements of the filled skutterudite SmRu4P12 have been carried out in several applied magnetic fields. The line width of the 31P-NMR spectrum rapidly increases below the metal-insulator transition temperature TMI, which indicates the appearance of an internal field below the temperature. Though no distinct anomaly

Bernd Rosenow, Andreas Glatz, Thomas Nattermann

The temperature ($T$) and frequency ($ω$) dependent conductivity of weakly disordered Luttinger liquids is calculated in a systematic way both by perturbation theory and from a finite temperature renormalization group (RG) treatment to leading order in the disorder strength. Whereas perturbation theory results in $ω/T$ scaling of the conductivity such scalin

R. Seguin, S. Rodt, A. Strittmatter, L. Reißmann

Cathodoluminescence spectra employing a shadow mask technique of InGaN layers grown by metal organic chemical vapor deposition on Si(111) substrates are reported. Sharp lines originating from InGaN quantum dots are observed. Temperature dependent measurements reveal thermally induced carrier redistribution between the quantum dots. Spectral diffusion is obse

K. Noda, M. Akaki, F. Nakamura, D. Akahoshi

We have investigated orthorhombic $R$MnO$_{3}$ ($R$=(Gd$_{1-y}$Tb$_{y}$)) crystals near the phase boundary between the paraelectric $A$-type-antiferromagnetic (AF) phase (PA) and the ferroelectric transverse-spiral-AF one (FS). The spiral AF structure breaks inversion symmetry and induces the ferroelectric polarization through the inverse Dzyaloshinskii-Mori

K. Noda, M. Akaki, F. Nakamura, D. Akahoshi

We have investigated the role of the 4$f$ moment on the magnetoelectric (ME) effect of orthorhombic $R$MnO$_{3}$ ($R$=rare earth ions). In order to clarify the role of the 4$f$ moment, we prepared three samples: (Eu,Y)MnO$_{3}$ without the 4$f$ moment, TbMnO$_{3}$ with the anisotropic 4$f$ moment, and (Gd,Y)MnO$_{3}$ with the isotropic 4$f$ moment. The ferro

Sergey Nazarenko

Reconnections of quantum vortex filaments create sharp bends which degenerate into propagating Kelvin waves. These waves cascade their energy down-scale and their waveaction up-scale via weakly nonlinear interactions, and this is the main mechanism of turbulence at the scales less than the inter-vortex distance. In case of an idealised forcing concentrated a

N. Neel, J. Kroeger, L. Limot, K. Palotas

The tip of a low-temperature scanning tunneling microscope is brought into contact with individual Kondo impurities (cobalt atoms) adsorbed on a Cu(100) surface. A smooth transition from the tunneling regime to a point contact with a conductance of $G\approx\text{G}_0$ occurs. Spectroscopy in the contact regime, {\it i. e.}, at currents in a $μ\text{A}$ rang

J. J. Alonso, J. F. Fernandez

We simulate antiferromagnetic thin films. Dipole-dipole and antiferromagnetic exchange interactions as well as uniaxial and quadrupolar anisotropies are taken into account. Various phases unfold as the corresponding parameters, J, D and C, as well as the temperature T and the number n of film layers vary. We find (1) how the strength Delta_m of the anisotrop

R. A. Duine, P. M. Haney, A. S. Nunez, A. H. MacDonald

We use a ferromagnetic voltage probe model to study the influence of inelastic scattering on giant magnetoresistance and current-induced torques in ferromagnetic and antiferromagnetic metal spin valves. The model is based on the Green's function formulation of transport theory and represents spin-dependent and spin-independent inelastic scatterers by int

W. Vassen, T. Jeltes, J. M. McNamara, A. S. Tychkov

We give an overview of the experiments at the Laser Centre of the Vrije Universiteit in Amsterdam on ultracold gases of metastable helium-4 and helium-3 as well as mixtures of both isotopes. We describe our experimental setup and discuss our experiments on Bose-Einstein condensation of 4He* (more than 10 million atoms in a BEC) and sympathetic cooling of 3He

F. Evers, K. Burke

Recent progress in measuring the transport properties of individual molecules has triggered a substantial demand for {\it ab initio} transport calculations. Even though program packages are commercially available and placed on custom tailored to address this task, reliable information often is difficult and very time consuming to attain in the vast majority

L. M. Jensen, H. Mäkelä, C. J. Pethick

We consider the properties of a gas of bosonic diatomic molecules in the limit when few of the molecules are dissociated. Taking into account the effects of dissociation and scattering among molecules and atoms, we calculate the dispersion relation for a molecule, and the thermal depletion of the condensate. We calculate the dependence of the Bose-Einstein c

A. Comtet, P. Leboeuf, Satya N. Majumdar

We establish a connection between the level density of a gas of non-interacting bosons and the theory of extreme value statistics. Depending on the exponent that characterizes the growth of the underlying single-particle spectrum, we show that at a given excitation energy the limiting distribution function for the number of excited particles follows the thre

Pierre-Henri Chavanis, Clement Sire

In all spatial dimensions $d$, we study the static and dynamical properties of a generalized Smoluchowski equation which describes the evolution of a gas obeying a logotropic equation of state, $p=A\lnρ$. A logotrope can be viewed as a limiting form of polytrope ($p=Kρ^γ$, $γ=1+1/n$), with index $γ=0$ or $n=-1$. In the language of generalized thermodynamics,

Michael Bortz

An asymptotic low-temperature expansion is performed for an integrable bosonic lattice model and for the critical spin-1/2 Heisenberg chain in a magnetic field. The results apply to the integrable Bose gas as well. We also comment on a high-temperature expansion of the bosonic lattice model.

Xiaoming Mao, Paul M. Goldbart, Xiangjun Xing, Annette Zippelius

Spatial heterogeneity in the elastic properties of soft random solids is investigated via a two-pronged approach. First, a nonlocal phenomenological model for the elastic free energy is examined. This features a quenched random kernel, which induces randomness in the residual stress and Lame coefficients. Second, a semi-microscopic model network is explored

C. C. Silva, H. W. Leite Alves, L. M. R. Scolfaro

We present, in this work, our theoretical results for the phonon dispersions and the frequency dependence of the reflectivities and the dielectric constants of ZrO2 and HfO2 in the monoclinic phase. The results show the importance of the lattice contribution for the evaluation of the static dielectric constant. Also, besides the anisotropy shown by these mat

S. C. Badescu, T. L. Reinecke

We show that the low lying spin states of two electrons in a semiconductor quantum dot can be strongly mixed by electron-electron asymmetric exchange. This mixing is generated by the coupling of electron spin to its orbital motion and to the relative orbital motion of the two electrons. The asymmetric exchange can be as large as 50% of the isotropic exchange

Debasish Chaudhuri

Systems under external confinement and constraints often show interesting properties. In this thesis, we study some systems under external confinement. We begin by finding out the probability distribution of end-to-end separation of a Worm Like Chain (WLC) polymer whose ends are positionally (and orientationally) constrained. We use Monte-Carlo simulations (

C. Oleyar, J. Talbot

We examine the reversible adsorption of hard spheres on a random site surface in which the adsorption sites are uniformly and randomly distributed on a plane. Each site can be occupied by one solute provided that the nearest occupied site is at least one diameter away. We use a numerical method to obtain the adsorption isotherm, i.e. the number of adsorbed p

J. Finjord, A. Hiorth, U. H. a Lad, S. M. Skjaeveland

We consider analytical and numerical solution of NMR relaxation under the condition of surface relaxation in an equilateral triangular geometry. We present an analytical expression for the Green's function in this geometry. We calculate the transverse magnetic relaxation without magnetic gradients present, single-phase, both analytically and numerically.

Jonathan C. Tan

I review the status of massive star formation theories: accretion from collapsing, massive, turbulent cores; competitive accretion; and stellar collisions. I conclude the observational and theoretical evidence favors the first of these models. I then discuss: the initial conditions of star cluster formation as traced by infrared dark clouds; the cluster form

P. C. Frisch

The heliosphere serves as a probe of interstellar material (ISM) close to the Sun. Measurements of ISM inside and outside of the heliosphere show that we reside in typical warm partially ionized ISM that can be successfully modeled using equilibrium photoionization models. The heliosphere wake leaves a ~200 X 1000 AU trail in space of low density, n<0.05 /cc

M. Long, M. M. Romanova, R. V. E. Lovelace

Disc accretion to a rotating star with a non-dipole magnetic field is investigated for the first time in full three-dimensional (3D) magnetohydrodynamic (MHD) simulations. We investigated the cases of (1) pure dipole, (2) pure quadrupole, and (3) dipole plus quadrupole fields. Simulations have shown that in each case the structure of the funnel streams and a

Baojiu Li, Ming-Chung Chu

We calculate in this article the CMB and matter power spectra of a class of early $f(R)$ cosmologies, which takes the form of $f(R) = R + λ_1 H_0^2\text{exp}[R/(λ_2 H_0^2)]$. Unlike the late-time $f(R)$ cosmologies such as $f(R) = R + α(-R)^β$ ($β<0$), the deviation from $Λ\text{CDM}$ of this model occurs at a higher redshift (thus the name \emph{Early $f(R)

Michael Seiffert, Colin Borys, Douglas Scott, Mark Halpern

We report the results of pointed observations of the prototypical ultra-luminous infrared galaxy (ULIRG) Arp 220 at 850 microns using the polarimeter on the SCUBA instrument on the James Clerk Maxwell Telescope. We find a Bayesian 99 per cent confidence upper limit on the polarized emission for Arp 220 of 1.54 per cent, averaged over the 15 arcsec beam-size.

Adrienne L. Erickcek, Tristan L. Smith, Marc Kamionkowski

Shortly after the addition of a 1/R term to the Einstein-Hilbert action was proposed as a solution to the cosmic-acceleration puzzle, Chiba showed that such a theory violates Solar System tests of gravity. A flurry of recent papers have called Chiba&#39;s result into question. They argue that the spherically-symmetric vacuum spacetime in this theory is the S

C. Goddi, L. Moscadelli, A. Sanna, R. Cesaroni

Most previous high-angular (<0.1 arcsec) resolution studies of molecular masers in high-mass star forming regions (SFRs) have concentrated mainly on either water or methanol masers. While high-angular resolution observations have clarified that water masers originate from shocks associated with protostellar jets, different environments have been proposed in

Pau Amaro-Seoane

HST observations reveal that young massive star clusters form in gas-rich environments like the Antennæ galaxy which will merge in collisional processes to form larger structures. These clusters amalgamate and if some of these clusters harbour a massive black hole in their centres, they can become a strong source of gravitational waves when they coalesce. In

Pau Amaro-Seoane, Marc Freitag

Observations suggest that star clusters often form in binaries or larger bound groups. Therefore, mergers between two clusters are likely to occur. If these clusters both harbor an intermediate-mass black hole (IMBH; 10^{2-4} Msun) in their center, they can become a strong source of gravitational waves when the black holes merge with each other. In order to

Padelis P. Papadopoulos

It has been recently argued that the HCN J=1--0 line emission may not be an unbiased tracer of dense molecular gas ($\rm n\ga 10^4 cm^{-3}$) in Luminous Infrared Galaxies (LIRGs: $\rm L_{FIR}> 10^{11} L_{\odot}$) and HCO$^+$ J=1--0 may constitute a better tracer instead (Graciá-Carpio et al. 2006), casting doubt into earlier claims supporting the former as a

S. Tsygankov, A. Lutovinov, E. Churazov, R. Sunyaev

We present the results of broad band (3-100 keV) observations of several X-ray pulsars with the INTEGRAL and RXTE observatories. We concentrate on the luminosity and energy dependence of the pulse profile and the variations of the cyclotron line energy. In V0332+53 the line energy changes nearly linearly with the source luminosity, while in 4U0115+63 its beh

John B. Stephen, A. Malizia, L. Bassani

In order to help in the identification of INTEGRAL/ISGRI sources, we have developed a software package which allows a rapid and detailed cross-correlation to be performed between various source catalogues. It allows subsets of catalogues to be constructed at a selected level of probability of association, which can then be used to construct multi-waveband co

Eunwoo Choi, Paul J. Wiita, Dongsu Ryu

We have studied three-dimensional hydrodynamic interactions of relativistic extragalactic jets with two-phase ambient media. These jets propagate through a denser homogeneous gas and then impact clouds with densities 100 to 1000 times higher than the initial beam density. The deflection angle of the jet is influenced more by the density contrast of the cloud

S. Recchi, G. Hensler

Due to their low gravitational energies, dwarf galaxies are greatly exposed to energetical influences from internal and external sources. By means of chemodynamical models we show that their star formation is inherently self-regulated, that peculiar abundance ratios can only be achieved assuming different star-formation episodes and that evaporation of inter

A. Miglio, J. Montalban, C. Maceroni, J. De Ridder

12 Bootis is a double-lined spectroscopic binary whose orbit has been resolved by interferometry. We present a detailed modelling of the system and show that the available observational constraints can be reproduced by models at different evolutionary stages, depending on the details of extra-mixing processes acting in the central regions. In order to discri

Chris Clarkson, Sanjeev S. Seahra

We report on the possibility of detecting a submillimetre-sized extra dimension by observing gravitational waves (GWs) emitted by pointlike objects orbiting a braneworld black hole. Matter in the `visible&#39; universe can generate a discrete spectrum of high frequency GWs with amplitudes moderately weaker than the predictions of general relativity (GR), whi

Vincenzo Testa, Marcella Marconi, Ilaria Musella, Vincenzo Ripepi

Near infrared (IR) studies of Cepheid variables in the LMC take advantage of the reduced light curve amplitude and metallicity dependence at these wavelengths. This work presents such photometry for two young clusters known to contain sizeable Cepheid populations: NGC 1866 and NGC 2031. Our goal is to determine light curves and period-luminosity (PL) relatio

S. Geier, C. Karl, H. Edelmann, U. Heber

The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with unseen compact companions to derive their masses and clarify their nature. Radial velocity curves were obtained from time

Stefano Ettori

I discuss the role of the sedimentation of helium in galaxy cluster cores on the observed X-ray properties and present a history of the metal accumulation in the ICM, with new calculations with respect to my previous work following the recent evidence of a bi-modal distribution of the delay time in Supernovae Type Ia.

V. Konyves, Cs. Kiss, A. Moor, Z. Kiss

Aims: An all-sky survey of loop- and arc-like intensity enhancements has been performed in order to investigate the large-scale structure of the diffuse far-infrared emission. Methods: We used maps made of 60 and 100 micrometer processed IRAS data (Sky Survey Atlas and dust infrared emission maps) to identify large-scale structures: loops, arcs or cavities,

M. Lugaro, A. I. Karakas, L. R. Nittler, C. M. O&#39;D. Alexander

Microscopic presolar grains extracted from primitive meteorites have extremely anomalous isotopic compositions revealing the stellar origin of these grains. The composition of presolar spinel grain OC2 is different from that of all other presolar spinel grains. Large excesses of the heavy Mg isotopes are present and thus an origin from an intermediate-mass (

C. Le Poncin-Lafitte, S. Lambert

The new generation of atomic clocks will reach unprecedented uncertainties in frequency of $10^{-18}$. In order to prepare space missions such as ACES, we compute all relativistic frequency shifts detectable during this mission in the case of a clock aboard the International Space Station.

P. Teyssandier, C. Le Poncin-Lafitte

Almost all of the studies devoted to relativistic astrometry are based on the integration of the null geodesic differential equations. However, the gravitational deflection of light rays can be calculated by a different method, based on the determination of the bifunction giving half the squared geodesic distance between two arbitrary points-events, the so-c

John Lee Grenfell, Barbara Stracke, Philip von Paris, Beate Patzer

One of the prime goals of future investigations of extrasolar planets is to search for life as we know it. The Earth&#39;s biosphere is adapted to current conditions. How would the atmospheric chemistry of the Earth respond if we moved it to different orbital distances or changed its host star? This question is central to astrobiology and aids our understand

E. Poretti, A. F. Lanza, C. Maceroni, I. Pagano

The space mission CoRoT (COnvection, ROtation and planetary Transits) will offer the possibility to detect extrasolar planets by means of the transit method. The satellite will observe about 60000 targets in the range 11.0<V<16.0, located in five fields near the equator. The parts of the preparatory work in which the Italian community has been involved are d

A. Telleschi, M. Guedel, K. R. Briggs, S. L. Skinner

We present the first high-resolution X-ray spectrum of a prototypical Herbig star (AB Aurigae), measure and interpret various spectral features, and compare our results with model predictions. We use X-ray spectroscopy data from XMM-Newton. The spectra are interpreted using thermal, optically thin emission models with variable element abundances and a photoe

M. Vigelius, A. Melatos, S. Chatterjee, B. M. Gaensler

We present three-dimensional, nonrelativistic, hydrodynamic simulations of bow shocks in pulsar wind nebulae. The simulations are performed for a range of initial and boundary conditions to quantify the degree of asymmetry produced by latitudinal variations in the momentum flux of the pulsar wind, radiative cooling in the postshock flow, and density gradient

I. Prandoni, R. A. Laing, P. Parma, H. R. de Ruiter

We discuss CO spectral line data of a volume-limited sample of 23 nearby (z<0.03) low luminosity radio galaxies, selected from the B2 catalogue. We investigate whether the CO properties of our sample are correlated with the properties of the host galaxy, and in particular with the dust component. We find strong evidences for a physical link between the dust

Andrew King, Emma Olsson, Melvyn B. Davies

We consider gamma--ray bursts produced by the merger of a massive white dwarf with a neutron star. We show that these are likely to produce long--duration GRBs, in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation, and occur close to the host galaxy. However

Jun Pan

The fractional Brownian motion with index $α$ is introduced to construct the fractional excursion set model. A new mass function with single parameter $α$ is derived within the formalism, of which the Press-Schechter mass function (PS) is a special case when $α=1/2$. Although the new mass function is computed assuming spherical collapse, comparison with the

A. W. Zaharow

Jeans instability of finite massive bodies at hydrostatic equilibrium is studied. Differential equation governing the evolution of infinitesimal disturbances is derived. We take into account radial inhomogeneity of mass density and other fluid parameters at the equilibrium state. Dispersion relation and a simple analytical formula, generalizing the Jeans cri

S. A. Farrell, P. M. O&#39;Neill, R. K. Sood, S. Dieters

We report the results of radio and X-ray observations of the high mass X-ray binary 2S 0114+650, made with the Giant Meterwave Radio Telescope and the Rossi X-ray Timing Explorer respectively. No emission was detected at radio wavelengths. The neutral hydrogen column density was found to vary over the orbital period, while no variability over the the super-o

David Merritt, Stefan Harfst, Gianfranco Bertone

We show that the presence of a rho~1/r^{3/2} dark matter overdensity can be robustly predicted at the center of any galaxy old enough to have grown a power-law density cusp in the stars via the Bahcall-Wolf mechanism. Using both Fokker-Planck and direct N-body integrations, we demonstrate collisional generation of these dark matter &#34;crests&#34; (Collisio

Thomas M. Fiore, Igor Kriz

We define the Jacobian of a Riemann surface with analytically parametrized boundary components. These Jacobians belong to a moduli space of ``open abelian varieties&#39;&#39; which satisfies gluing axioms similar to those of Riemann surfaces, and therefore allows a notion of ``conformal field theory&#39;&#39; to be defined on this space. We further prove tha

Olimpia Lombardi, Mario Castagnino

The aim of this paper is to introduce a new member of the family of the modal interpretations of quantum mechanics. In this modal-Hamiltonian interpretation, the Hamiltonian of the quantum system plays a decisive role in the property-ascription rule that selects the definite-valued observables whose possible values become actual. We show that this interpreta

Itai Benjamini, Gady Kozma, Nicholas Wormald

We show that the total variation mixing time of the simple random walk on the giant component of supercritical Erdos-Renyi graphs is log^2 n. This statement was only recently proved, independently, by Fountoulakis and Reed. Our proof follows from a structure result for these graphs which is interesting in its own right. We show that these graphs are &#34;dec

J. Wosiek

After summarizing briefly some numerical results for four-dimensional supersymmetric SU(2) Yang-Mills quantum mechanics, we review a recent study of systems with an infinite number of colours. We study in detail a particular supersymmetric matrix model which exhibits a phase transition, strong-weak duality, and a rich structure of supersymmetric vacua. In th

N. G. Antoniou, F. K. Diakonos, E. N. Saridakis, G. A. Tsolias

We consider the classical evolution of a lattice of non-linear coupled oscillators for a special case of initial conditions resembling the equilibrium state of a macroscopic thermal system at the critical point. The displacements of the oscillators define initially a fractal measure on the lattice associated with the scaling properties of the order parameter

Yong Hou

In this paper we prove that there exists a positive number $λ>0$, such that any 2-generated Kleinian groups with limit set of Hausdorff dimension $<λ$ are classical Schottky groups.

Manjari Bagchi, Jishnu Dey, Sushan Konar, Gour Bhattacharya

One interesting method of constraining the dense matter Equations of State is to measure the advancement of the periastron of the orbit of a binary radio pulsar (when it belongs to a double neutron star system). There is a great deal of interest on applicability of this procedure to the double pulsar system PSR J0737-3039 (A/B). Although the above method can

Matthias Kuenzer

Suppose given functors A x A&#39; -F-> B -G-> C between abelian categories, an object X in A and an object X&#39; in A&#39; such that certain conditions hold. We show that, E_1-terms exempt, the Grothendieck spectral sequence of the composition of F(X,-) and G evaluated at X&#39; is isomorphic to the Grothendieck spectral sequence of the composition of F(-,X

Raoul Santachiara, Franck Stauffer, Daniel Cabra

We study the one-particle von Neumann entropy of a system of N hard-core anyons on a ring. The entropy is found to have a clear dependence on the anyonic parameter which characterizes the generalized fractional statistics described by the anyons. This confirms the entanglement as a valuable measure to investigate topological properties of quantum states. Fur

Z. H. Peng, H. F. Chu, Z. D. Wang, D. N. Zheng

We have developed an adiabatic Abelian geometric quantum computation strategy based on the non-degenerate energy eigenstates in (but not limited to) superconducting phase-qubit systems. The fidelity of the designed quantum gate was evaluated in the presence of simulated thermal fluctuation in superconducting phase qubits circuit and was found to be rather ro

I. L. Zhogin

Absolute Parallelism (AP) has many interesting features: large symmetry group of equations; field irreducibility with respect to this group; vast list of consistent second order equations not restricted to Lagrangian ones. There is the variant of AP which solutions are free of arising singularities if D=5; in this case AP acquires topological features of non

Geoffrey G. Potter, Gerhard Muller, Michael Karbach

We present exact and explicit results for the thermodynamic properties (isochores, isotherms, isobars, response functions, velocity of sound) of a quantum gas in dimensions D>=1 and with fractional exclusion statistics 0<=g<=1 connecting bosons (g=0) and fermions (g=1). In D=1 the results are equivalent to those of the Calogero-Sutherland model. Emphasis is

Lasse Rempe

Let f be an entire function with a bounded set of singular values, and suppose furthermore that the postsingular set of f is bounded. We show that every component of the escaping set I(f) is unbounded. This provides a partial answer to a question of Eremenko.

Suphot Musiri, George Siopsis

We calculate analytically the asymptotic form of quasi-normal modes of perturbations of arbitrary spin of a Schwarzschild black hole including first-order corrections. We use the Teukolsky equation which applies to both bosonic and fermionic modes. Remarkably, we arrive at explicit expressions which coincide with those derived using the Regge-Wheeler equatio

Stefan Groot Nibbelink, Marco Peloso, Matthew Sexton

We propose a non-linear extension of the Fierz-Pauli mass for the graviton through a functional of the vielbein and an external Minkowski background. The functional generalizes the notion of the measure, since it reduces to a cosmological constant if the external background is formally sent to zero. Such a term and the explicit external background, emerge dy

Pedro J. Silva

Using the general framework developed in hep-th/0607056, we study in detail the phase space of BPS Black Holes in AdS, for the case where all three electric charges are equal. Although these solitons are supersymmetric with zero Hawking temperature, it turns out that these Black Holes have rich phase structure with sharp phase transitions associated to a cor

G. Roux, E. Orignac, P. Pujol, D. Poilblanc

We review the properties of two coupled fermionic chains, or ladders, under a magnetic field parallel to the lattice plane. Results are computed by complementary analytical (bosonization) and numerical (density-matrix renormalization group) methods which allows a systematic comparison. Limiting cases such as coupled bands and coupled chains regimes are discu

S. Giagu

We report the observation of $\B_s^0-\bar{B}_s^0$ oscillations performed by the CDF II detector using a data sample of 1 $fb^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.96 \TeV$. We measure the probability as a function of proper decay time that the $B_s$ decays with the same, or opposite, flavor as the flavor at production, and we find a signal for $\B_s^

Arafa H Aly, Jamila Douari

The quantization of the current in a superconducting quantum point contact is reviewed and the critical current is discussed at different temperatures depending on the carrier concentration as well by suggesting a constant potential in the semiconductor and then a Maxwell potential. When the Fermi wave length is comparable with the constriction width we show

Ali Mesbah, Arie van Deursen

Recently, a new web development technique for creating interactive web applications, dubbed AJAX, has emerged. In this new model, the single-page web interface is composed of individual components which can be updated/replaced independently. With the rise of AJAX web applications classical multi-page web applications are becoming legacy systems. If until a y

N. S. Kardashev, I. D. Novikov, A. A. Shatskiy

We consider the hypothesis that some active galactic nuclei and other compact astrophysical objects may be current or former entrances to wormholes. A broad mass spectrum for astrophysical wormholes is possible. We consider various new models of the static wormholes including wormholes maintained mainly by an electromagnetic field. We also discuss observatio

Yoritoshi Adachi, Takashi Yamamoto, Masato Koashi, Nobuyuki Imoto

We propose an efficient quantum key distribution protocol based on the photon-pair generation from parametric down-conversion (PDC). It uses the same experimental setup as the conventional protocol, but a refined data analysis enables detection of photon-number splitting attacks by utilizing information from a built-in decoy state. Assuming the use of practi