August 2005 arXiv papers — page 6
Showing 501–600 of 3,714 papers
Nigel Goldenfeld, Badrinarayan P. Athreya, Jonathan A. Dantzig
Dendritic growth, and the formation of material microstructure in general, necessarily involves a wide range of length scales from the atomic up to sample dimensions. The phase field approach of Langer, enhanced by optimal asymptotic methods and adaptive mesh refinement, copes with this range of scales, and provides an effective way to move phase boundaries.
Haibing Peng, Jene A. Golovchenko
Carbon nanotube field-effect transistors (FETs) with passivated coaxial gate structures have been fabricated after growth of contacted suspended single wall nanotubes (SWNTs) and subsequent coating with gate dielectrics. Electron Fabry-Perot interferences are observed in the FETs indicating ballistic transport in the coated structures. Reliable production of
Juan Colmenero, Angel J. Moreno, Angel Alegria
Among the different dynamical processes that take place in polymers, methyl group rotation is perhaps the simplest one, since all the relevant interactions on the methyl group can be condensed in an effective mean-field one-dimensional potential. Recent experimental neutron scattering results have stimulated a new revival of the interest on methyl group dyna
V. Cvetkovic, Z. Nussinov, J. Zaanen
Topological defects play an important role in physics of elastic media and liquid crystals. Their kinematics is determined by constraints of topological origin. An example is the glide motion of dislocations which has been extensively studied by metallurgists. In a recent theoretical study dealing with quantum dualities associated with the quantum melting of
Creation, detection and decoherence of Schrodinger cat states in Bose-Einstein condensates
cond-mat.otherY. P. Huang, M. G. Moore
We study the possibility to create many-particle Schrödinger cat-like states by using a Feshbach resonance to reverse the sign of the scattering length of a Bose-Einstein condensate trapped in a double-well potential. To address the issue of experimental verification of coherence in the cat-like state, we study the revival of the initial condensate state in
Transition pressures and enthalpy barriers for the cd->beta-tin transition in Si and Ge under non-hydrostatic conditions
cond-mat.mtrl-sciKatalin Gaal-Nagy, Dieter Strauch
We present an ab-initio study of the phase transition cd->beta-tin in Si and Ge under hydrostatic and non-hydrostatic pressure. For this purpose we have developed a new method to calculate the influence of non-hydrostatic pressure components not only on the transition pressure but also on the enthalpy barriers between the phases. We find good agreement with
Radiation-induced magnetotransport in high-mobility two-dimensional systems: Role of electron heating
cond-mat.mes-hallX. L. Lei, S. Y. Liu
Effects of microwave radiation on magnetoresistance are analyzed in a balance-equation scheme that covers regimes of inter- and intra-Landau level processes and takes account of photon-asissted electron transitions as well as radiation-induced change of the electron distribution for high mobility two-dimensional systems. Short-range scatterings due to backgr
S. Wuester, T. E. Argue, C. M. Savage
We show that the stability of three-dimensional Skyrmions in trapped Bose-Einstein condensates depends critically on scattering lengths, atom numbers, trap rotation and trap anisotropy. In particular, for the $^{87}$Rb $|F=1,m_{f}=-1>$, $|F=2,m_{f}=1>$ hyperfine states stability is sensitive to the scattering lengths at the level of their present experimenta
F. Ye, J. A. Fernandez-Baca, Pengcheng Dai, J. W. Lynn
We use neutron scattering to study the spin and charge/orbital ordering (CO-OO) in the nearly half-doped perovskite manganite $Pr_{0.55}(Ca_{0.8}Sr_{0.2})_{0.45}MnO_3$ (PCSMO). On cooling from room temperature, PCSMO first enters into a CO-OO state below $T_{CO}$ and then becomes a CE-type long-range ordered antiferromagnet below $T_N$. At temperatures above
M. Kollar, M. Eckstein, K. Byczuk, N. Blümer
We calculate the local Green function for a quantum-mechanical particle with hopping between nearest and next-nearest neighbors on the Bethe lattice, where the on-site energies may alternate on sublattices. For infinite connectivity the renormalized perturbation expansion is carried out by counting all non-self-intersecting paths, leading to an implicit equa
Topological approach to phase transitions and inequivalence of statistical ensembles
cond-mat.stat-mechMichael Kastner
The relation between thermodynamic phase transitions in classical systems and topology changes in their state space is discussed for systems in which equivalence of statistical ensembles does not hold. As an example, the spherical model with mean field-type interactions is considered. Exact results for microcanonical and canonical quantities are compared wit
Density dependent spin susceptibility and effective mass in interacting quasi-two dimensional electron systems
cond-mat.str-elYing Zhang, S. Das Sarma
Motivated by recent experimental reports, we carry out a Fermi liquid many-body calculation of the interaction induced renormalization of the spin susceptibility and effective mass in realistic two dimensional (2D) electron systems as a function of carrier density using the leading-order `ladder-bubble' expansion in the dynamically screened Coulomb inter
Stellar Kinematics and Populations of Early-Type Galaxies with the SAURON and OASIS Integral-Field Spectrographs
astro-phR. M. McDermid, R. Bacon, H. Kuntschner, E. Emsellem
We summarise the results and achievements of integral-field spectroscopy of early-type galaxies, observed as part of a survey using both the SAURON and OASIS spectrographs. From the perspective of integral-field spectroscopy, these otherwise smooth and featureless objects show a wealth of structure, both in their stellar kinematics and populations. We focus
Peggy Varniere, J. E. Bjorkman, Adam Frank Alice C. Quillen, A. C. Carciofi
We study the effects of an annular gap induced by an embedded proto-planet on disk scattered light images and the infrared spectral energy distribution. We find that the outer edge of a gap is brighter in the scattered light images than a similar location in a gap-free disk. The stellar radiation that would have been scattered by material within in the gap i
A Complete Survey of the Transient Radio Sky and Implications for Gamma-Ray Bursts, Supernovae, and other Relativistic Explosions
astro-phAvishay Gal-Yam, Eran O. Ofek, Dovi Poznanski, Amir Levinson
We had previously reported on a survey for radio transients, used to set an upper limit on the number of orphan gamma-ray burst (GRB) radio afterglows, and thus a lower limit on the typical GRB beaming factor. Here we report radio and optical follow-up observations of these possible transients, achieving the first full characterization of the transient radio
Sara L. Ellison, Lisa J. Kewley
We calculate the oxygen abundances for ~45,000 star-forming galaxies selected from the SDSS using nine popular `strong-line' metallicity diagnostics. We find that individual galaxies can have metallicities which differ by factors of up to ~4, depending on the choice of abundance diagnostic. The resulting mass-metallicity relations subsequently exhibit si
Ralf Lehnert
Many theoretical approaches to quantum gravity predict the breakdown of Lorentz symmetry at Planck energies. Kinematical cosmic-ray studies are a sensitive tool in the search for such effects. This talk discusses the construction of test dispersion relations for such analyses.
I. Jung, M. Groza, J. Perkins, H. Krawczynski
Cadmium Zinc Telluride (CZT) achieves excellent spatial resolution and good energy resolution over the broad energy range from several keV into the MeV energy range. In this paper we present the results of a systematic study of the performance of CZT detectors manufacturered by Orbotech (before IMARAD) depending on surface preparation, contact materials and
L. Piro, A. De Rosa, G. Matt, G. C. Perola
The Seyfert 1 galaxy NGC4151 is characterized by complex X-ray absorption, well described by a dual absorber, composed of a uniform mildly ionized gas and a cold system that partially covers the central source. However, in one of the 5 BeppoSAX observations, the spectrum shows two peculiar features. An absorption feature is detected around 8.5-9 keV with a s
P. Favre, T. J. -L. Courvoisier, S. Paltani
We analyse the ultraviolet variability time scales in a sample of 15 Type 1 Active Galactic Nuclei (AGN) observed by IUE. Using a structure function analysis, we demonstrate the existence in most objects of a maximum variability time scale of the order of 0.02-1.00 year. We do not find any significant dependence of these maximum variability time scales on th
Probing the formation of intermediate- to high-mass stars in protoclusters: A detailed millimeter study of the NGC 2264 clumps
astro-phN. Peretto, Ph. Andre, A. Belloche
We present the results of dust continuum and molecular line observations of two massive cluster-forming clumps, NGC 2264-C and NGC 2264-D, including extensive mapping performed with the MAMBO bolometer array and the HERA heterodyne array on the IRAM 30m telescope. Both NGC 2264 clumps are located in the Mon OB1 giant molecular cloud complex, adjacent to one
J. Snigula, C. A. Goessl, U. Hopp
Dwarf galaxies in the local group provide a unique astrophysical laboratory. In particular, they allow us to probe pulsating (and other) variable stars in low-metallicity environments with abundances below that of the SMC. Our observing program, described in detail by C. Gössl's contribution, yields a large number of intrinsically bright variable stars t
W. de Boer, C. Sander, V. Zhukov, A. V. Gladyshev
The public data from the EGRET space telescope on diffuse Galactic gamma rays in the energy range from 0.1 to 10 GeV are reanalyzed with the purpose of searching for signals of Dark Matter annihilation (DMA). The analysis confirms the previously observed excess for energies above 1 GeV in comparison with the expectations from conventional Galactic models. In
M. Bureau, G. Aronica, E. Athanassoula
Kn-band imaging of a sample of 30 edge-on spiral galaxies with a boxy or peanut-shaped (B/PS) bulge is discussed. Galaxies with a B/PS bulge tend to have a more complex morphology than galaxies with other bulge types, unsharp-masked images revealing structures that trace the major orbit families of three-dimensional bars. Their surface brightness profiles ar
Two years of INTEGRAL monitoring of the Soft Gamma-Ray Repeater SGR 1806-20: from quiescence to frenzy
astro-phD. Gotz, S. Mereghetti, S. Molkov, K. Hurley
SGR 1806-20 has been observed for more than 2 years with the INTEGRAL satellite. In this period the source went from a quiescent state into a very active one culminating in a giant flare on December 27 2004. Here we report on the properties of all the short bursts detected with INTEGRAL before the giant flare. We derive their number-intensity distribution an
M. Falanga, L. Kuiper, J. Poutanen, E. W. Bonning
Simultaneous observations of the accretion-powered millisecond pulsar IGR J00291+5934 by International Gamma-Ray Astrophysics Laboratory and Rossi X-ray Timing Explorer during the 2004 December outburst are analysed. The average spectrum is well described by thermal Comptonization with an electron temperature of 50 keV and Thomson optical depth tau_T ~ 1 in
A. Mirizzi, G. G. Raffelt
We analyze the neutrino events from the supernova (SN) 1987A detected by the Kamiokande II (KII) and Irvine-Michigan-Brookhaven (IMB) experiments. For the time-integrated flux we assume a quasi-thermal spectrum of the form $(E/E_0)^αe^{-(α+1)E/E_0}$ where $α$ plays the role of a spectral index. This simple representation not only allows one to fit the total
FUSE determination of a low deuterium abundance along an extended sight line in the Galactic disk
astro-phG. Hebrard, T. M. Tripp, P. Chayer, S. D. Friedman
We present a study of the deuterium abundance along the extended sight line (2.7kpc) toward HD 90087 with FUSE. Both in terms of distance and column densities, HD 90087 has the longest and densest sight line observed in the Galactic disk for which a deuterium abundance has been measured from UV absorption lines. Because many interstellar clouds are probed al
A. C. Gonzalez-Garcia, J. A. L. Aguerri, M. Balcells
We have run high resolution N-body models simulating the encounter of a dwarf galaxy with a bright elliptical galaxy. The dwarf absorbs orbital angular momentum and shows counter-rotating features in the external regions of the galaxy. To explain the core-envelope kinematic decoupling observed in some dwarf galaxies in high-density environments requires near
Hans Kjeldsen, Timothy R. Bedding, R. Paul Butler, Joergen Christensen-Dalsgaard
We have made velocity observations of the star alpha Cen B from two sites, allowing us to identify 37 oscillation modes with l=0-3. Fitting to these modes gives the large and small frequency separations as a function of frequency. The mode lifetime, as measured from the scatter of the oscillation frequencies about a smooth trend, is similar to that in the Su
G. Risaliti, S. Bianchi, G. Matt, A. Baldi
We present the discovery of four absorption lines in the X-ray spectrum of the Seyfert Galaxy NGC 1365, at energies between 6.7 and 8.3 keV. The lines are detected with high statistical confidence (from >20sigma for the strongest to \~4sigma for the weakest) in two XMM-Newton observations 60 ksec long. We also detect the same lines, with lower signal-to-nois
F. Eisenhauer, G. Perrin, S. Rabien, A. Eckart
We present the proposal for the infrared adaptive optics (AO) assisted, two-object, high-throughput, multiple-beam-combiner GRAVITY for the VLTI. This instrument will be optimized for phase-referenced interferometric imaging and narrow-angle astrometry of faint, red objects. Following the scientific drivers, we analyze the VLTI infrastructure, and subsequent
A. Ford, R. D. Jeffries, B. Smalley
High resolution spectroscopy is used to determine the detailed chemical abundances of a group of eight F- and G-type stars in the young open cluster Blanco 1. An average [Fe/H] of +0.04 +/- 0.02 (internal error) +/- 0.04 (external error) is found, considerably lower than a previous spectroscopic estimate for this cluster. The difference is due mainly to our
D. Pourbaix, G. R. Knapp, P. Szkody, Z. Ivezic
We have examined the radial velocity data for stars spectroscopically observed by the Sloan Digital Sky Survey (SDSS) more than once to investigate the incidence of spectroscopic binaries, and to evaluate the accuracy of the SDSS stellar radial velocities. We find agreement between the fraction of stars with significant velocity variations and the expected f
Philip Yock
Earth-like extra-solar planets may be detected with 1-2m class telescopes using the gravitational microlensing technique. The essential requirement is the ability to be able to carry out continuous observations of the galactic bulge. A telescope situated at Dome A or Dome C in Antarctica would be eminently suitable. Two possible observing strategies are desc
Y. C. Zou, X. F. Wu, Z. G. Dai
When a cold shell sweeps up the ambient medium, a forward shock and a reverse shock will form. We analyze the reverse-forward shocks in a wind environment, including their dynamics and emission. An early afterglow is emitted from the shocked shell, e.g., an optical flash may emerge. The reverse shock behaves differently in two approximations: relativistic an
Puxun Wu, Hongwei Yu
The effects of the gravitational back reaction of cosmological perturbations are investigated in a cosmological model where the universe is dominated by phantom energy. We assume a COBE normalized spectrum of cosmological fluctuations at the present time and calculate the effective energy-momentum tensor of the gravitational back-reactions of cosmological pe
Olivier Schiffmann
This paper is a sequel to math.AG/0505148, where the Hall algebra U^+_E of the category of coherent sheaves on an elliptic curve E defined over a finite field was explicitly described, and shown to be a two-parameter deformation of the ring of diagonal invariants R^+=C[x_1^{\pm 1}, ..., y_1,...]^{S_{\infty}} (in infinitely many variables). In the present wor
L. Clavelli
In the string landscape picture, the effective potential is characterized by an enormous number of local minima of which only a minuscule fraction are suitable for the evolution of life. In this "multiverse", random transitions are continually made between the various minima with the most likely transitions being to minima of lower vacuum energy. The
Takeshi Nihei
We study pair annihilations of the neutralino dark matter in the minimal supersymmetric standard model with CP violation. We consider the case that the higgsino mass and the trilinear scalar couplings have CP-violating phases of order unity, taking a scenario that the scalar fermions in the first two generations are much heavier than those in the third gener
Claude Sabbah
We show that the Fourier-Laplace transform of a regular holonomic module over the Weyl algebra of one variable, which generically underlies a variation of polarized Hodge structure, underlies itself an integrable variation of polarized twistor structure.
Frans Pretorius, Matthew W. Choptuik
We present a modification to the Berger and Oliger adaptive mesh refinement algorithm designed to solve systems of coupled, non-linear, hyperbolic and elliptic partial differential equations. Such systems typically arise during constrained evolution of the field equations of general relativity. The novel aspect of this algorithm is a technique of "extrap
Francisco S. N. Lobo
The gravastar picture is an alternative model to the concept of a black hole, where there is an effective phase transition at or near where the event horizon is expected to form, and the interior is replaced by a de Sitter condensate. In this work, a generalization of the gravastar picture is explored, by considering a matching of an interior solution govern
Richard A. Brown, Roy Maartens, Eleftherios Papantonopoulos, Vassilis Zamarias
Brane-world models offer the possibility of explaining the late acceleration of the universe via infra-red modifications to General Relativity, rather than a dark energy field. However, one also expects ultra-violet modifications to General Relativity, when high-energy stringy effects in the early universe begin to grow. We generalize the DGP brane-world mod
Ulrich Bunke, Thomas Schick
We study the topology of T-duality for pairs of U(1)-bundles and three-dimensional integral cohomology classes over orbispaces. In particular, our results apply to U(1)-spaces with finite isotropy. We generalize the theory developed in our previous paper math.GT/0405132 from spaces to orbispaces.
Tsuyoshi Ito, Hiroshi Imai, David Avis
We show that some two-party Bell inequalities with two-valued observables are stronger than the CHSH inequality for 3 \otimes 3 isotropic states in the sense that they are violated by some isotropic states in the 3 \otimes 3 system that do not violate the CHSH inequality. These Bell inequalities are obtained by applying triangular elimination to the list of
Elsa Abreu, Pedro Bicudo
Lattice computations with excited SU(3) representations suggest that the confining gluon-gluon interaction complies with the Casimir scaling. The constituent gluon models have also been assuming the Casimir scaling. Inspired in type-II superconductors, we explore a new scenario for the gluon-gluon interaction where the adjoint string is replaced by a pair of
Takahiro Tanaka
We give a short personally-biased review on the recent progress in our understanding of gravitational radiation reaction acting on a point particle orbiting a black hole. The main motivation of this study is to obtain sufficiently precise gravitational waveforms from inspiraling binary compact stars with a large mass ratio. For this purpose, various new conc
Relationship between the rise width and the full width of gamma-ray burst pulses and its implications in terms of the fireball model
astro-phRui-Jing Lu, Yi-Ping Qin, Ting-Feng Yi
Kocevski et al. (2003) found that there is a linear relation between the rise width and the full width of gamma-ray burst pulses detected by the BATSE instrument based on their empirical functions. Motivated by this, we investigate the relationship based on Qin et al. (2004) model. Theoretical analysis shows that each of the two quantities, the rise width an
Ming-Shyang Chang, Wei Chen, Hsiu-Hau Lin
We studied the correlated quasi-one-dimensional systems by one-loop renormalization group techniques in weak coupling. In contrast to conventional g-ology approach, we formulate the theory in terms of bilinear currents and obtain all possible interaction vertices. Furthermore, the one-loop renormalization group equations are derived by operator product expan
Simultaneous amplitude and phase damping of a kind of Gaussian states and their separability
quant-phXiao-Yu Chen
We give out the time evolution solution of simultaneous amplitude and phase damping for any continuous variable state. For the simultaneous amplitude and phase damping of a wide class of two- mode entangled Gaussian states, two analytical conditions of the separability are given. One is the sufficient condition of separability. The other is the condition of
Ainslie Yuen, Plamen Ch. Ivanov
The NYSE and NASDAQ stock markets have very different structures and there is continuing controversy over whether differences in stock price behaviour are due to market structure or company characteristics. As the influence of market structure on stock prices may be obscured by exogenous factors such as demand and supply, we hypothesize that modulation of th
F. A. Barone, C. Farina
We show how the induction law is correctly used in the path integral computation of the free particle propagator. The way this primary path integral example is treated in most textbooks is a little bit missleading.
F. A. Barone, C. Farina
We show how the pre-exponential factor of the Feynman propagator for the harmonic oscillator can be computed by the generalized $ζ$-function method. Besides, we establish a direct equivalence between this method and Schwinger's propertime method.
Design of high-order short-time approximations as a problem of matching the covariance of a Brownian motion
math-phCristian Predescu
One of the outstanding problems in the numerical discretization of the Feynman-Kac formula calls for the design of arbitrary-order short-time approximations that are constructed in a stable way, yet only require knowledge of the potential function. In essence, the problem asks for the development of a functional analogue to the Gauss quadrature technique for
Matthew Daws
We investigate the notion of Connes-amenability for dual Banach algebras, as introduced by Runde, for bidual algebras and weighted semigroup algebras. We provide some simplifications to the notion of a $σWC$-virtual diagonal, as introduced by Runde, especially in the case of the bidual of an Arens regular Banach algebra. We apply these results to discrete, w
Michael Reissig, Jens Wirth
This expository article is intended to give an overview about recently achieved results on asymptotic properties of solutions to the Cauchy problem $u_{tt}-Δu+b(t)u_t =0,\qquad u(0,\cdot)=u_1,\quad \mathrm{D}_tu(0,\cdot)=u_2$ for a wave equation with time-dependent dissipation term. The results are based on structural properties of the Fourier multipliers re
D. Ring
The radiation rate of an evaporating black hole is calculated in a toy model in which the geometry outside the collapsing matter is described by a Vaidya metric. When back reaction consistency is imposed, the singularity in the blueshift factor near the horizon is softened, suppressing the evaporation rate in the Schwarzschild case by the fourth power of the
Eric Laenen, Lorenzo Magnea
We show that higher-order coefficients required to perform threshold resummation for electroweak annihilation processes, such as Drell-Yan or Higgs production via gluon fusion, can be computed using perturbative results derived in Deep Inelastic Scattering. As an example, we compute the three-loop coefficient D_3, generating most of the fourth tower of thres
Mitsuru Kakizaki, Shigeki Matsumoto, Yoshio Sato, Masato Senami
We reevaluate the thermal relic density of the Kaluza-Klein (KK) dark matter in universal extra dimension models. In particular, we consider the effect of the resonance caused by second KK particles on the density. We find that the annihilation cross sections relevant to the density are significantly enhanced due to the resonance when the Higgs boson mass is
Akinbo Ojo
Modifying the standard hot big bang model of cosmology with an inflationary event has been very successful in resolving most of the outstanding cosmological problems. The various inflationary mechanisms proposed depend on the production of expansion from exotic phenomena, false vacuum, scalar fields or other exotic particle behaviour within an environment of
Bruno Marnette, Viktor Kuncak, Martin Rinard
Typestate systems ensure many desirable properties of imperative programs, including initialization of object fields and correct use of stateful library interfaces. Abstract sets with cardinality constraints naturally generalize typestate properties: relationships between the typestates of objects can be expressed as subset and disjointness relations on sets
F. W. S. Lima
On directed Barabasi-Albert networks with two and seven neighbours selected by each added site, the Ising model does not seem to show a spontaneous magnetisation. Instead, the decay time for flipping of the magnetisation follows an Arrhenius law for Metropolis and Glauber algorithms, but for Wolff cluster flipping the magnetisation decays exponentially with
Jie Liu, Chuanwei Zhang, Mark G. Raizen, Qian Niu
A periodically kicked ring of a Bose-Einstein condensate is considered as a nonlinear generalization of the quantum kicked rotor, where the nonlinearity stems from the mean field interactions between the condensed atoms. For weak interactions, periodic motion (anti-resonance) becomes quasiperiodic (quantum beating) but remains stable. There exists a critical
Elisheva Cohen, David A. Kessler, Herbert Levine
We expand on a previous study of fronts in finite particle number reaction-diffusion systems in the presence of a reaction rate gradient in the direction of the front motion. We study the system via reaction-diffusion equations, using the expedient of a cutoff in the reaction rate below some critical density to capture the essential role of fl uctuations in
Analytical solution of the time evolution of an entangled electron spin pair in a double quantum dot nanostructure
cond-mat.mes-hallM. Blaauboer
Using master equations we present an analytical solution of the time evolution of an entangled electron spin pair which can occupy 36 different quantum states in a double quantum dot nanostructure. This solution is exact given a few realistic assumptions and takes into account relaxation and decoherence rates of the electron spins as phenomenological paramet
Kyaw Zin Win, Narayanan Menon
We assess the relative importance of spatial congestion and lowered temperature in the slowing dynamics of supercooled glycerol near the glass transition. We independently vary both volume, V, and temperature, T, by applying high pressure and monitor the dynamics by measuring the dielectric susceptibility. Our results demonstrate that both variables are cont
Global Perturbation Configurations in a Composite Disc System with an Isopedic Magnetic Field
astro-phY. -Q. Lou, Y. Wu
We construct stationary global configurations of both aligned and unaligned logarithmic spiral perturbations in a composite disc system of stellar and isopedically magnetized gaseous singular isothermal discs (SIDs) coupled by gravity. The thin gaseous SID is threaded across by a vertical magnetic field B_z with a constant ratio of the surface gas mass densi
A. Del Popolo
We use the model for the migration of planets introduced in Del Popolo, Yesilyurt & Ercan (2003) to calculate the observed mass and semimajor axis distribution of extra-solar planets. The assumption that the surface density in planetesimals is proportional to that of gas is relaxed, and in order to describe disc evolution we use a method which, using a serie
A. Doi, S. Kameno, K. Kohno, K. Nakanishi
We investigate the high-frequency radio spectra of twenty low-luminosity active galactic nuclei (LLAGNs) with compact radio cores. Our millimetre survey with the Nobeyama Millimetre Array (NMA) and analyses of submillimetre archival data that had been obtained with the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JC
Close Binary Interactions of Intermediate-Mass Black Holes: Possible Ultra-Luminous X-ray Sources?
astro-phL. Blecha, N. Ivanova, V. Kalogera, K. Belczynski
While many observed ultra-luminous X-ray sources (ULXs, Lx > 10^39 erg s^-1) could be extragalactic X-ray binaries (XRBs) emitting close to the Eddington limit, the highest-luminosity ULXs (Lx > 3x10^39 erg s^-1) exceed the isotropic Eddington luminosity for even high-stellar-mass accreting black hole XRBs. It has been suggested that these highest-luminosity
Rui-Jing Lu, Yi-Ping Qin
Qin et al. (2004) have derived a formula of count rates based on a model of highly symmetric expanding fireballs, where the Doppler effect is the key factor to be concerned. In this paper, we employ the formula to both the Qin model and the uniform jet model to study how the rising timescale, $Δτ_{θ,r}$, and the decay timescale, $Δτ_{θ,d}$, of a local pulse
Sudipto Guha, Andrew McGregor, Suresh Venkatasubramanian
In many problems in data mining and machine learning, data items that need to be clustered or classified are not points in a high-dimensional space, but are distributions (points on a high dimensional simplex). For distributions, natural measures of distance are not the $\ell_p$ norms and variants, but information-theoretic measures like the Kullback-Leibler
Masanori Hanada, Hikaru Kawai, Yusuke Kimura
It is shown that a covariant derivative on any d-dimensional manifold M can be mapped to a set of d operators acting on the space of functions on the principal Spin(d)-bundle over M. In other words, any d-dimensional manifold can be described in terms of d operators acting on an infinite dimensional space. Therefore it is natural to introduce a new interpret
Raman spectroscopy and field emission measurements on catalytically grown carbon nanotubes
cond-mat.mtrl-sciChristian Klinke, Ralph Kurt, Jean-Marc Bonard, Klaus Kern
We used microcontact printing to pattern a silicon surface with an iron-containing catalytic solution. Multi-wall carbon nanotubes were subsequently grown on the patterned areas by chemical vapor deposition at temperatures between 650 and 1000C. We demonstrate that the diameter of the catalytically grown multi-wall nanotubes increases with the deposition tem
V. V. Gvaramadze
The supernova remnant S147 harbors the pulsar PSR J0538+2817 whose characteristic age is more than an order of magnitude greater than the kinematic age of the system (inferred from the angular offset of the pulsar from the geometric center of the supernova remnant and the pulsar proper motion). To reconcile this discrepancy we propose that PSR J0538+2817 cou
The Lense-Thirring effect in the Jovian system of the Galilean satellites and its measurability
gr-qcLorenzo Iorio, Valery Lainey
In this paper we investigate the possibility of measuring the post-Newtonian general relativistic gravitomagnetic Lense-Thirring effect in the Jovian system of its Galilean satellites Io, Europa, Ganymede and Callisto in view of recent developments in processing and modelling their optical observations spanning a large time interval (125 years). The present
Yu-Xiao Liu, Yi-Shi Duan, Li-Jie Zhang
In Randall-Sundrum models, by the use of general Noether theorem, the covariant angular momentum conservation law is obtained with the respect to the local Lorentz transformations. The angular momentum current has also superpotential and is therefore identically conserved. The space-like components $J_{ij}$ of the angular momentum for Randall-Sundrum models
Gongxian Xu, Cheng Shao, Zhilong Xiu
The presented previously indirect optimization method (IOM) developed within biochemical systems theory (BST) provides a versatile and mathematically tractable optimization strategy for biochemical systems. However, due to the local approximations nature of the BST formalism, the iterative version of this technique possibly does not yield the true optimum so
S. Sazonov, E. Churazov, M. Revnivtsev, A. Vikhlinin
We report the results of identification of 8 hard X-ray sources discovered by the INTEGRAL observatory during the ongoing all-sky survey. These sources have been observed by Chandra. In 6 cases a bright X-ray source was found within the INTEGRAL localization region, which permitted to unambigously identify 5 of the objects with nearby galaxies, implying that
Density Matrix in Quantum Mechanics and Distinctness of Ensembles Having the Same Compressed Density Matrix
quant-phGui Lu Long, Yi-Fan Zhou, Jia-Qi Jin, Yang Sun
We clarify different definitions of the density matrix by proposing the use of different names, the full density matrix for a single-closed quantum system, the compressed density matrix for the averaged single molecule state from an ensemble of molecules, and the reduced density matrix for a part of an entangled quantum system, respectively. We show that ens
Schwarzschild Tests of the Wahlquist-Estabrook-Buchman-Bardeen Tetrad Formulation for Numerical Relativity
gr-qcL. T. Buchman, J. M. Bardeen
A first order symmetric hyperbolic tetrad formulation of the Einstein equations developed by Estabrook and Wahlquist and put into a form suitable for numerical relativity by Buchman and Bardeen (the WEBB formulation) is adapted to explicit spherical symmetry and tested for accuracy and stability in the evolution of spherically symmetric black holes (the Schw
Kamiokande Collaboration
The details of Super--Kamiokande--I's solar neutrino analysis are given. Solar neutrino measurement in Super--Kamiokande is a high statistics collection of $^8$B solar neutrinos via neutrino-electron scattering. The analysis method and results of the 1496 day data sample are presented. The final oscillation results for the data are also presented.
Carlos M. Naón, Mariano J. Salvay, Marta L. Trobo
We investigate conformal properties of a one-dimensional quantum system with a long-range, Coulomb-like potential of the form $\frac{1}{|x|^σ}$, with $σ>0$. We compute the conformal anomaly $c$ as function of $σ$. We obtain $c=0$ for $σ<1$ (Wigner crystal) and $c=1$ for $σ>1$ (Luttinger liquid). By studying the scaling regime of the system when it is deforme
Hendrik van Hees, Vincenzo Greco, Ralf Rapp
Thermalization and collective flow of charm (c) and bottom (b) quarks in ultra-relativistic heavy-ion collisions are evaluated based on elastic parton rescattering in an expanding quark-gluon plasma (QGP). We show that resonant interactions in a strongly interacting QGP (sQGP), as well as the effects of parton coalescence, can play an essential role in the i
Zhe Sun, XiaoGuang Wang, AnZi Hu, You-Quan Li
By using the concept of negativity, we investigate entanglement in (1/2,1) mixed-spin Heisenberg systems. We obtain the analytical results of entanglement in small isotropic Heisenberg clusters with only nearest-neighbor (NN) interactions up to four spins and in the four-spin Heisenberg model with both NN and next-nearest-neighbor (NNN) interactions. For mor
Modified Bennett-Brassard 1984 Quantum Key Distribution With Two-way Classical Communications
quant-phKai Wen, Gui Lu Long
The quantum key distribution protocol without public announcement of bases is equipped with a two-way classical communication symmetric entanglement purification protocol. This modified key distribution protocol is unconditionally secure and has a higher tolerable error rate of 20%, which is higher than previous scheme without public announcement of bases.
A. Kwang-Hua Chu
We demonstrate the effects of an induced disorder (or a free-orientation : $θ$ which is related to the relative direction of scattering of particles w.r.t. to the normal of the propagating plane-wave front) upon the possible resonance of the plane (sound) wave propagating in Bose gases by using the quantum kinetic equations. We firstly present the diverse di
A. Kwang-Hua Chu
We define some physical variables associated with the traversing sequences of electrons along the orbit which is a 2D projection of 8$_{18}$-knot. The configuration is regular but the resulting contributions, which are related to the physical variable, of those combinations from all the possible states to the fixed spatial sites show certain irregular behavi
Monwhea Jeng
The beliefs of physicists can bias their results towards their expectations in a number of ways. We survey a variety of historical cases of expectation bias in observations, experiments, and calculations.
Yu. Chesnokov, V. Biryukov, V. Kryshkin
Calibration of the forward CMS hadron calorimeters in situ by the LHC beam is proposed. Simulations show that bent crystal channeling technique is feasible at the LHC, and report the experience of IHEP Protvino in bending 70 GeV protons by 9 degrees (150 mrad) during 10 years in 1994-2004 experiments. Practical realization of calibration scheme based on simu
Hermann Uys, John D. Perreault, Alexander D. Cronin
Decoherence due to scattering from background gas particles is observed for the first time in a Mach-Zehnder atom interferometer, and compared with decoherence due to scattering photons. A single theory is shown to describe decoherence due to scattering either atoms or photons. Predictions from this theory are tested by experiments with different species of
Dipole resonances in light neutron-rich nuclei studied with time-dependent calculations of antisymmetrized molecular dynamics
nucl-thY. Kanada-En'yo, M. Kimura
In order to study isovector dipole response of neutron-rich nuclei, we have applied a time-dependent method of antisymmetrized molecular dynamics. The dipole resonances in Be, B and C isotopes have been investigated. In $^{10}$Be, $^{15}$B, $^{16}$C, collective modes of the vibration between a core and valence neutrons cause soft resonances at the excitation
K. Kaneko, M. Hasegawa
Thermal behavior of isoscalar and isovector proton-neutron (pn) pairing energies at finite temperature are investigated by the shell model calculations. These pn pairing energies can be estimated by double differences of "thermal" energies which are extended from the double differences of binding energies as the indicators of pn pairing energies at z
Paolo Lipparini
We present a new and useful congruence identity satisfied by m-permutable varieties.
Noncommmutative Gelfand Duality for not necessarily unital $C^*$-algebras, Jordan Canonical form, and the existence of invariant subspaces
math.FAMukul S. Patel
Gelfand-Naimark duality (Commutative $C^*$-algebras $\equiv$ Locally compact Hausdorff spaces) is extended to $C^*$-algebras $\equiv$ Quotient maps on locally compact Hausdorff spaces. Using this duality, we give for an \emph{arbitrary} bounded operator on a complex Hilbert space of several dimensions, a functional calculus and the existence theorem for nont
F. Peherstorfer, A. Volberg, P. Yuditskii
First we give here a simple proof of a remarkable result of Videnskii and Shirokov: let $B$ be a Blaschke product with $n$ zeros, then there exists an outer function $ϕ, ϕ(0)=1$, such that $\|(Bϕ)'\| \leq C n$, where $C$ is an absolute constant. Then we apply this result to a certain problem of finding the asymptotic of orthogonal polynomials.
Detlef Müller, Marco M. Peloso, Fulvio Ricci
We prove that, if Δ_1 is the Hodge Laplacian acting on differential 1-forms on the (2n+1)-dimensional Heisenberg group, and if m is a Mihlin-Hörmander multiplier on the positive half-line, with L^2-order of smoothness greater than n+1/2, then m(Δ_1) is L^p-bounded for 1<p<\infty. Our approach leads to an explicit description of the spectral decomposition of
Connection between deriving bridges and radial parts from multidimensional Ornstein-Uhlenbeck processes
math.PRMatyas Barczy, Gyula Pap
First we give a construction of bridges derived from a general Markov process using only its transition densities. We give sufficient conditions for their existence and uniqueness (in law). Then we prove that the law of the radial part of the bridge with endpoints zero derived from a special multidimensional Ornstein-Uhlenbeck process equals the law of the b
Hao Pan, Hui-Qin Cao
In this paper we establish a $q$-analogue of a congruence of Sun concerning the products of binomial coefficients modulo the square of a prime.