November 2005 arXiv papers — page 44

T. Corbitt, Y. Chen, F. Khalili, D. Ottaway

We propose an experiment to extract ponderomotive squeezing from an interferometer with high circulating power and low mass mirrors. In this interferometer, optical resonances of the arm cavities are detuned from the laser frequency, creating a mechanical rigidity that dramatically suppresses displacement noise. After taking into account imperfection of opti

A. Brunini, R. G. Cionco

We have withdrawn this paper because we have presented the basic results in Brunini & Cionco (2005), Icarus 177, 264

Aguston E. Eiben, Marc Schoenauer

Evolutionary computing (EC) is an exciting development in Computer Science. It amounts to building, applying and studying algorithms based on the Darwinian principles of natural selection. In this paper we briefly introduce the main concepts behind evolutionary computing. We present the main components all evolutionary algorithms (EA), sketch the differences

Martin Kutz

Any planar graph has a crossing-free straight-line drawing in the plane. A simultaneous geometric embedding of two n-vertex graphs is a straight-line drawing of both graphs on a common set of n points, such that the edges withing each individual graph do not cross. We consider simultaneous embeddings of two labeled trees, with predescribed vertex corresponde

Sergey V. Buldyrev, John Ferrante, Fredy R. Zypman

This paper presents experimental evidence and theoretical models supporting that dry friction stick-slip is described by self-organized criticality. We use the data, obtained with a pin-on-disc tribometer set to measure lateral force to examine the variation of the friction force as a function of time. We study nominally flat surfaces of aluminum and steel.

Guangyu Zhang, David Mann, Li Zhang, Ali Javey

An oxygen assisted hydrocarbon chemical vapor deposition (CVD) method is developed to afford large-scale highly reproducible ultra high-yield growth of vertical single-walled carbon nanotubes (SWNT). It is revealed that reactive hydrogen (H)-species, inevitable in hydrocarbon-based growth, are damaging to the formation of sp2-like SWNTs. The addition of oxyg

Ramon Reigada, Javier Buceta, Katja Lindenberg

We present a nonequlibrium approach for the study of a flexible bilayer whose two components induce distinct curvatures. In turn, the two components are interconverted by an externally promoted reaction. Phase separation of the two species in the surface results in the growth of domains characterized by different local composition and curvature modulations.

Ramon Reigada, Javier Buceta, Katja Lindenberg

A simple kinetic model of a two-component deformable and reactive bilayer is presented. The two differently shaped components are interconverted by a nonequilibrium reaction, and a phenomenological coupling between local composition and curvature is proposed. When the two components are not miscible, linear stability analysis predicts, and numerical simulati

Sandipan Pramanik, Carmen Gabriela Stefanita, Supriyo Bandyopadhyay

We report experimental study of spin transport in all-metal nanowire spin valve structures. The nanowires have a diameter of 50 nm and consist of three layers - cobalt, copper and nickel. Based on the experimental observations, we conclude that the primary spin relxation mechanism in the paramagnet copper is the Elliott-Yafet mode associated with frequent in

Pierre Henry-Labordere

In this paper we provide an extensive classification of one and two dimensional diffusion processes which admit an exact solution to the Kolmogorov (and hence Black-Scholes) equation (in terms of hypergeometric functions). By identifying the one-dimensional solvable processes with the class of integrable superpotentials introduced recently in supersymmetric

Sandipan Pramanik, Supriyo Bandyopadhyay, Marc Cahay

The classical drift diffusion (DD) model of spin transport treats spin relaxation via an empirical parameter known as the ``spin diffusion length''. According to this model, the ensemble averaged spin of electrons drifting and diffusing in a solid decays exponentially with distance due to spin dephasing interactions. The characteristic length scale a

M. Mayr, G. Alvarez, C. Sen, E. Dagotto

We present a numerically exact solution for the BCS Hamiltonian at any temperature, including the degrees of freedom associated with classical phase, as well as amplitude, fluctuations via a Monte Carlo (MC) integration. This allows for an investigation over the whole range of couplings: from weak attraction, as in the well-known BCS limit, to the mainly une

K. -H. Han, A. Talyzin, A. Dzwilewski, T. L. Makarova

Two sets of samples were synthesized at 3.5 GPa near the point of C60 cage collapse at different annealing times. A clear structural transformation from mixture of C60 polymeric phases to graphite-like hard carbon phase was confirmed by X-ray diffraction and Raman spectroscopy. Magnetic force microscopy and superconducting quantum interference device were us

P. Abbamonte, A. Rusydi, S. Smadici, G. D. Gu

Stripe phases were predicted to arise in doped antiferromagnets through competition between magnetism and the kinetic energy of mobile carriers (typically holes). In copper-oxides the main experimental evidence for stripes is neutron scattering from La1.48Nd0.4Sr0.12CuO4 (LNSCO) and La1.875Ba0.125CuO4 (LBCO) which reveals coexisting static spin and charge or

O. Zobay, Georgios M. Nikolopoulos

We study superradiant scattering off Bose-Einstein condensates by solving the semiclassical Maxwell-Schroedinger equations describing the coupled dynamics of matter-wave and optical fields. Taking the spatial dependence of these fields along the condensate axis into account, we are able to reproduce and explain many of the characteristic features observed in

A. B. Beznosov, E. L. Fertman, P. P. Pal-Val, L. N. Pal-Val

The structural phase transformation in the La2/3Ba1/3MnO3 perovskite manganite was studied by ultrasound, neutron diffraction and electron microscopy techniques. Minima of the velocity and maxima of the decrement of the ultrasound point out the structural transition temperature Ts=200 K. The hysteretic temperature behavior and giant alteration of the ultraso

A. Scherz, E. K. U. Gross, H. Appel, C. Sorg

The 2p-3d core hole interaction in the L2,3 absorption spectra of the 3d transition metals is treated within time-dependent density functional theory (TDDFT). A simple three-level model explains the origin of the strong deviations from the one-particle branching ratio and yields matrix elements of the unknown exchange-correlation (XC) kernel directly from ex

Hiroshi Kontani

We study optical conductivities for high-Tc superconductors under the magnetic field on the basis of the microscopic Fermi liquid theory. Current vertex corrections (CVC's) are correctly taken into account to satisfy the conservation laws, which has been performed for the first time for optical conductivities based on the fluctuation-exchange (FLEX) appr

H. Casini, M. Huerta

We find the analytic expression of the trace of powers of the reduced density matrix on an interval of length L, for a massive boson field in 1+1 dimensions. This is given exactly (except for a non universal factor) in terms of a finite sum of solutions of non linear differential equations of the Painlevé V type. Our method is a generalization of one introdu

T. Ishikawa, H. Nagara, K. Kusakabe, N. Suzuki

We have explored the unknown structure of the phosphorus in the phase IV (P-IV phase) based on the first-principles calculations using the metadynamics simulation method. Starting from the simple cubic structure, we found a new modulated structure of a monoclinic lattice. The modulation is crucial to the stability of the structure. Refining further the struc

J. E. Williams, N. Nygaard, C. W. Clark

Starting with coupled atom-molecule Boltzmann equations, we develop a simplified model to understand molecule formation observed in recent experiments. Our theory predicts several key features: (1) the effective adiabatic rate constant is proportional to density; (2) in an adiabatic ramp, the dependence of molecular fraction on magnetic field resembles an er

L. Schweitzer, P. Markoš

The sample averaged longitudinal two-terminal conductance and the respective Kubo-conductivity are calculated at quantum critical points in the integer quantum Hall regime. In the limit of large system size, both transport quantities are found to be the same within numerical uncertainty in the lowest Landau band, $0.60\pm 0.02 e^2/h$ and $0.58\pm 0.03 e^2/h$

Nobukatsu Yoshida, Mikael Fogelstrom

We report on mutual proximity effects in d-wave superconductor/half-metal heterostructures which correspond to systems composed of high-Tc cuprates and manganite materials. In our study, proximity effects are induced by the interplay of two separate interface effects: spin-mixing (or rotation) surface scattering and spin-flip scattering. The surface spin-mix

Isao Endo, Hiroshi Koibuchi

A tethered surface model is investigated by using the canonical Monte Carlo simulation technique on a torus with an intrinsic curvature. We find that the model undergoes a first-order phase transition between the smooth phase and the crumpled one.

L. C. Garcia de Andrade

The Riemannian geometry of elastica in one and two dimensions is considered. An example is given of the deflexion or Frenet curvature of the elastic filament rod where the Riemannian curvature vanishes, since the curve is one dimensional. However the Frenet curvature scalar appears on the Levi-Civita-Christoffel symbol of the Riemannian geometry. A second ex

Malay Bandyopadhyay

We have studied the transport process in the two dimensional electron gas (2DEG) in presence of a magnetic field and a dissipative environment at temperature T. By means of imaginary time series functional integral method we calculate the decay rates at finite temperature and in the presence of dissipation. We have studied decay rates for wide range of tempe

M. Hagiwara, H. Tsujii, C. R. Rotundu, B. Andraka

Specific heat experiments on single crystals of the S=1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C_9H_24N_4)(NO_2)ClO_4, alias NTENP, have been performed in magnetic fields applied both parallel and perpendicular to the spin chains. We have found for the parallel field configuration that the magnetic specific heat (C_mag) is proportional to

Robert L. Jack, Juan. P. Garrahan

We consider two systems of Ising spins with plaquette interactions. They are simple models of glasses which have dual representations as kinetically constrained systems. These models allow an explicit analysis using the mosaic, or entropic droplet, approach of the random first-order transition theory of the glass transition. We show that the low temperature

Bradley A. Foreman

This paper examines the properties of the self-energy operator in lattice-matched semiconductor heterostructures, focusing on nonanalytic behavior at small values of the crystal momentum, which gives rise to long-range Coulomb potentials. A nonlinear response theory is developed for nonlocal spin-dependent perturbing potentials. The ionic pseudopotential of

Bradley A. Foreman

In this paper a multi-band envelope-function Hamiltonian for lattice-matched semiconductor heterostructures is derived from first-principles norm-conserving pseudopotentials. The theory is applicable to isovalent or heterovalent heterostructures with macroscopically neutral interfaces and no spontaneous bulk polarization. The key assumption -- proved in earl

Jonathan M. Gelbord, Kimberly A. Weaver, Tahir Yaqoob

We have discovered a correlation between the X-ray absorbing column densities within Seyfert galaxies and the relative alignment between the central engines and their host galactic disks. This correlation carries several implications for Seyfert unification models. (1) In addition to small-scale circumnuclear absorbers, there are absorbing systems associated

Alison J. Farmer, Peter Goldreich

We revisit the dynamics of Prometheus and Pandora, two small moons flanking Saturn's F ring. Departures of their orbits from freely precessing ellipses result from mutual interactions via their 121:118 mean motion resonance. Motions are chaotic because the resonance is split into four overlapping components. Orbital longitudes were observed to drift away

Ohad Shemmer, Niel Brandt

In the two parts of this contribution we describe two related XMM-Newton programs. The first part summarizes our study of the X-ray spectral properties and variability of z>4 quasars (Shemmer et al. 2005). The second part presents preliminary results from our ongoing XMM-Newton program to investigate the X-ray spectral properties and variability of luminous,

Adrián Brunini, Rodolfo G. Cionco

The sample of known exoplanets is strongly biased to masses larger than the ones of the giant gaseous planets of the solar system. Recently, the discovery of two extrasolar planets of considerably lower masses around the nearby stars GJ 436 and $ρ$ Cancri was reported. They are like our outermost icy giants, Uranus and Neptune, but in contrast, these new pla

Scott C. Porter, Somak Raychaudhury

The Pisces-Cetus supercluster (redshift z~0.06) is one of the richest nearby (z<0.1) superclusters of galaxies, and emerges as a remarkable filament of galaxies at the edges of the two-degree-field galaxy redshift survey and the ongoing Sloan Digital Sky Survey. We explore the extent of the supercluster on the sky and in redshift space, and map the distribut

Jonathan Granot, Pawan Kumar

The early X-ray afterglow for a significant number of gamma-ray bursts detected by the Swift satellite is observed to have a phase of very slow flux decline with time ($F_ν\propto t^{-α}$ with $0.2 \lesssim α\lesssim 0.8$) for $10^{2.5} s \lesssim t \lesssim 10^4$ s, while the subsequent decline is the usual $1 \lesssim α_3 \lesssim 1.5$ behavior, that was s

Jorick S. Vink

The amount of mass loss is of fundamental importance to the lives and deaths of very massive stars, the input of chemical elements and momentum into the interstellar and intergalactic media, as well as the emitted ionizing radiation. I review mass-loss predictions for hot massive stars as a function of metal content for groups of OB stars, Luminous Blue Vari

Shangli Ou

We introduce a new technique for constructing three-dimensional (3D) models of incompressible Riemann S-type ellipsoids and compressible triaxial configurations that share the same velocity field as that of Riemann S-type ellipsoids. Our incompressible models are exact steady-state configurations; our compressible models represent approximate steady-state eq

Ignasi Ribas, Carme Jordi, Francesc Vilardell, Edward L. Fitzpatrick

We present the first detailed spectroscopic and photometric analysis of an eclipsing binary in the Andromeda Galaxy (M31). This is a 19.3-mag semi-detached system with components of late-O and early-B spectral types. From the light and radial velocity curves we have carried out an accurate determination of the masses and radii of the components. Their effect

O. Kotov, A. Vikhlinin

We present spatially-resolved analysis of the temperature and gas density profiles in 6 relaxed galaxy clusters at z = 0.4-0.54 using long-exposure Chandra observations. We derived the total cluster masses within the radius r_500 assuming hydrostatic equilibrium but without assuming isothermality of the intracluster gas. Together with a similar study based o

Jonathan L. Feng

Recent breakthroughs in cosmology reveal that a quarter of the Universe is composed of dark matter, but the microscopic identity of dark matter remains a deep mystery. I review recent progress in resolving this puzzle, focusing on two well-motivated classes of dark matter candidates: WIMPs and superWIMPs. These possibilities have similar motivations: they ex

David N. Burrows, P. Romano, O. Godet, A. Falcone

The Swift XRT has been observing GRB afterglows since December 23, 2004. Three-quarters of these observations begin within 300 s of the burst onset, providing an unprecendented look at the behavior of X-ray emission from GRB afterglows in the first few hours after the burst. While most of the early afterglows have smoothly declining lightcurves, a substantia

C. Schoenaers, A. E. Lynas-Gray

In previous attempts to perform seismic modelling of pulsating subdwarf-B stars, various mode identification techniques are used with uncertain results. We investigated a method so far neglected in sdB stars, but very successful for Main Sequence pulsators, that is, mode identification from the line-profile variations caused by stellar pulsation. We report t

I. Minchev, A. C. Quillen

We consider a differentially rotating, 2D stellar disk perturbed by two steady state spiral density waves moving at different patterns speeds. Our investigation is based on direct numerical integration of initially circular test-particle orbits. We examine a range of spiral strengths and spiral speeds and show that stars in this time dependent gravitational

Nuria P. F. Lorente, Alistair C. H. Glasse, Gillian S. Wright

MIRI, the Mid-InfraRed Instrument, is one of four instruments being built for the James Webb Space Telescope. It is being developed jointly between an European Consortium (21 institutes from 10 countries, under the auspices of ESA), and the US. MIRI consists of an imager, a coronograph, a low-resolution spectrograph, and an Integral Field Unit (IFU) Medium R

Andrew King

Recent observations of young galaxies at redshifts z ~ 3 have revealed simultaneous AGN and starburst activity, as well as galaxy-wide superwinds. I show that there is probably a close connection between these phenomena by extending an earlier treatment of the M_BH - sigma relation (King, 2003). As the black hole grows, an outflow drives a shell into the sur

N. Bastian, R. P. Saglia, P. Goudfrooij, M. Kissler-Patig

We present high-dispersion spectra of two extremely massive star clusters in galactic merger remnants. One cluster, W30, is located in the ~500 Myr old merger remnant NGC 7252 and has a velocity dispersion and effective radius of sigma=27.5+-2.5 km/s and R_eff=9.3+-1.7 pc, respectively. The other cluster, G114, located in the ~3 Gyr old merger remnant NGC 13

C. Guidorzi, A. Monfardini, A. Gomboc, C. J. Mottram

The 2-m Liverpool Telescope (LT), owned by Liverpool John Moores University, is located in La Palma (Canary Islands) and operates in fully robotic mode. In 2005, the LT began conducting an automatic GRB follow-up program. On receiving an automatic GRB alert from a Gamma-Ray Observatory (Swift, INTEGRAL, HETE-II, IPN) the LT initiates a special override mode

M. Dessauges-Zavadsky, J. X. Prochaska, S. D&#39;Odorico, F. Calura

We present new elemental abundance studies of seven damped Lyman-alpha systems (DLAs). Together with the four DLAs analyzed in Dessauges-Zavadsky et al. (2004), we have a sample of eleven DLA galaxies with uniquely comprehensive and homogeneous abundance measurements. These observations allow one to study the abundance patterns of 22 elements and the chemica

D. Dravins, C. Barbieri, R. A. E. Fosbury, G. Naletto

QuantEYE is designed to be the highest time-resolution instrument on ESO:s planned Overwhelmingly Large Telescope, devised to explore astrophysical variability on microsecond and nanosecond scales, down to the quantum-optical limit. Expected phenomena include instabilities of photon-gas bubbles in accretion flows, p-mode oscillations in neutron stars, and qu

Vincent Desjacques, Martin G. Haehnelt, Adi Nusser

An excess of sight-lines close to Lyman-break galaxies (LBGs) with little or no absorption in QSO absorption spectra has been reported and has been interpreted as the effect of galactic winds on the Intergalactic Medium. We use here numerical simulations to investigate the flux probability function close to plausible sites of LBGs. We show that the flux dist

Yoshifusa Ita, Shuji Deguchi, Noriyuki Matsunaga, Hinako Fukushi

We studied the period-K magnitude (P-K) relations of nearby Mira and Mira-like variables with relatively good Hipparcos parallaxes. They form at least two prominent sequences on the P-K plane, corresponding to the sequences C (Mira variables pulsating in the fundamental mode) and C&#39;(Mira variables pulsating in the 1st overtone mode), that were found in t

W. Liu, X. P. Zhao, S. T. Wu, P. H. Scherrer

White-light observations of the solar corona show that there are two characteristic types of Coronal Mass Ejections (CMEs) in terms of speed-height profiles: so-called fast CMEs that attain high speeds low in the corona and slow CMEs that gradually accelerate from low initial speeds. Low and Zhang (2002) have recently proposed that fast and slow CMEs result

W. Pietsch

XMM-Newton EPIC observations reveal the population of X-ray sources of the bright Local Group spiral galaxy M 31, a low-star-formation-rate galaxy like the Milky Way, down to a 0.2-4.5 keV luminosity of 4.4E34 erg/s. With the help of X-ray hardness ratios and optical and radio information different source classes can be distinguished. The survey detected 856

Piero Ranalli, Andrea Comastri, Livia Origlia, Roberto Maiolino

We present the preliminary analysis of a deep (100ks) XMM-Newton observation of M82. The spatial distribution of the abundances of chemical elements (Fe, O, Ne, Mg, Si, S) is investigated through narrow-band imaging analisys and spatially-resolved spectroscopy. We find that the abundances of alpha-elements follow a bipolar distribution, these elements being

Angela Bragaglia, Monica Tosi

We describe a long term project aimed at deriving information on the chemical evolution of the Galactic disk from a large sample of open clusters. The main property of this project is that all clusters are analyzed in a homogeneous way, to guarantee the robustness of the ranking in age, distance and metallicity. Special emphasis is devoted to the evolution o

L. M. Oskinova, A. Feldmeier, W. -R. Hamann

It is commonly adopted that X-rays from O stars are produced deep inside the stellar wind, and transported outwards through the bulk of the expanding matter which attenuates the radiation and affects the shape of emission line profiles. The ability of Chandra and XMM-Newton to resolve these lines spectroscopically provided a stringent test for the theory of

Arnab K. Ray, J. K. Bhattacharjee

Modelling the flow in a thin accretion disc like a dynamical system, we analyse the nature of the critical points of the steady solutions of the flow. For the simple inviscid disc there are two critical points, with the outer one being a saddle point and the inner one a centre type point. For the weakly viscous disc, there are four possible critical points,

Tamara M. Davis, Brian P. Schmidt, Alex G. Kim

To use type Ia supernovae as standard candles for cosmology we need accurate broadband magnitudes. In practice the observed magnitude may differ from the ideal magnitude-redshift relationship either through intrinsic inhomogeneities in the type Ia supernova population or through observational error. Here we investigate how we can choose filter bandpasses to

Fumitaka Nakamura, Christopher F. McKee, Richard I. Klein, Robert T. Fisher

The effect of smooth cloud boundaries on the interaction of steady planar shock waves with interstellar clouds is studied using a high-resolution local AMR technique with a second-order accurate axisymmetric Godunov hydrodynamic scheme. A 3D calculation is also done to confirm the results of the 2D ones. We consider an initially spherical cloud whose density

Christopher J. Conselice

We present the results of a Keck spectroscopic study of globular clusters associated with the Virgo Cluster dwarf elliptical VCC 1386. We analyze blue spectroscopic absorption lines from 3500-5500 A for 13 globular cluster candidates and confirm that five are associated with VCC 1386. By comparing metal and Balmer line indices of these globular clusters with

E. M. L. Humphreys, L. J. Greenhill, M. J. Reid, H. Beuther

We report the first detection of an extragalactic millimeter wavelength H2O maser at 183 GHz towards NGC 3079 using the Submillimeter Array (SMA), and a tentative submillimeter wave detection of the 439 GHz maser towards the same source using the James Clerk Maxwell Telescope (JCMT). These H2O transitions are known to exhibit maser emission in star-forming r

Shin-ya Nitta

This paper investigates Magnetic Reynolds number dependence of the ``self-similar evolution model&#39;&#39; (Nitta et al. 2001) of fast magnetic reconnection. I focused my attention on the flow structure inside and around the reconnection outflow, which is essential to determine the entire reconnection system (Nitta et al. 2002). The outflow is consist of se

R. W. Pike, Michael J. Hudson

We compare the peculiar velocity field within 65 $h^{-1}$ Mpc predicted from 2MASS photometry and public redshift data to three independent peculiar velocity surveys based on type Ia supernovae, surface brightness fluctuations in ellipticals, and Tully-Fisher distances to spirals. The three peculiar velocity samples are each in good agreement with the predic

O. Almaini, J. S. Dunlop, C. J. Conselice, T. A. Targett

We present high-resolution imaging of a sample of 10 SCUBA submillimetre galaxies, obtained using the ACS camera on the Hubble Space Telescope. We find that the majority show compact, disturbed morphologies. Using quantitative morphological classification, we find that at least 6 are classified as major mergers. Simulations suggest that the morphological par

Jonathan L. Rosner

Since ordinary matter constitutes about 4% of the closure density of the Universe while dark matter constitutes about six times as much, it is urged that searches for dark matter consider that it may exist in several forms. Implications for detection and hadron and $e^+ e^-$ colliders are discussed.