October 2008 arXiv papers — page 58

Wilson Wong, Wei Liu, Mohammed Bennamoun

Most research related to unithood were conducted as part of a larger effort for the determination of termhood. Consequently, novelties are rare in this small sub-field of term extraction. In addition, existing work were mostly empirically motivated and derived. We propose a new probabilistically-derived measure, independent of any influences of termhood, tha

M. Zamaninasab, A. Eckart, L. Meyer, R. Schoedel

Here we report on recent near-infrared observations of the Sgr A* counterpart associated with the super-massive ~ 4x10^6 M_sun black hole at the Galactic Center. We find that the May 2007 flare shows the highest sub-flare contrast observed until now, as well as evidence for variations in the profile of consecutive sub-flares. We modeled the flare profile var

Roland Jesseit, Michele Cappellari, Thorsten Naab, Eric Emsellem

We use two-dimensional kinematic maps of simulated binary disc mergers to investigate the $λ_R$-parameter, which is a luminosity weighted measure of projected angular momentum per unit mass. This parameter was introduced to subdivide the SAURON sample of early type galaxies in so called fast $λ_R > 0.1$ and slow rotators $λ_R < 0.1$. Tests on merger remnants

Murat Alanyali, Maxim Dashouk

We analyze opportunistic schemes for transmission scheduling from one of $n$ homogeneous queues whose channel states fluctuate independently. Considered schemes consist of the LCQ policy, which transmits from a longest connected queue in the entire system, and its low-complexity variants that transmit from a longest queue within a randomly chosen subset of c

F. Tavecchio, G. Ghisellini

Recent observations in the TeV band challenge the simplest models developed to describe the overall emission of blazars and radiogalaxies. In particular, the observation of variable TeV emission from M87 and the fast variability shown by PKS 2155-304 challenge the standard framework. We discuss how the existence of a radial structure in the sub-pc scale jet,

Bhaskar Sen Gupta, Shankar P. Das, Jean-Louis Barrat

We solve numerically the equations of nonlinear fluctuating hydrodynamics (NFH) for the supercooled liquid. The time correlation of the density fluctuations in equilibrium obtained here shows quantitative agreement with molecular dynamics(MD) simulation data. We demonstrate numerically that the 1/rho nonlinearity in the NFH equations of motion is essential i

J. -C. Lanfranchi, C. Ciemniak, C. Coppi, F. von Feilitzsch

CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) is an experiment located at the Gran Sasso underground laboratory and aimed at the direct detection of dark matter in the form of WIMPs. The setup has just completed a one year commissioning run in 2007 and is presently starting a physics run with an increased target mass. Scintillating $

T. N. Pham

The nonet symmetry scheme seems to describe rather well the masses and $η-η^{\prime}$ mixing angle of the ground state pseudo-scalar mesons and is thus expected to be also a good approximation for the matrix elements of the pseudo-scalar density operators which play an important role in charmless two-body B decays with $η$ or $η^{\prime}$ in the final state.

P. S. Negi

We show that the mass-radius $(M-R)$ relation corresponding to the MIT bag models of strange quark matter (SQM) and the models obtained by Day et al (1998) do not provide the necessary and sufficient condition for dynamical stability for the equilibrium configurations, since such configurations can not even fulfill the necessary condition of hydrostatic equi

G. Fiori, G. Iannaccone

We explore the device potential of tunable-gap bilayer graphene FET exploiting the possibility of opening a bandgap in bilayer graphene by applying a vertical electric field via independent gate operation. We evaluate device behavior using atomistic simulations based on the self-consistent solution of the Poisson and Schroedinger equations within the NEGF fo

Anton Yu. Menshutin, Lev N. Shchur, Valery M. Vinokour

A finite size effect in the probing of the harmonic measure in simulation of diffusion-limited aggregation (DLA) growth is investigated. We introduce a variable size of probe particles, to estimate harmonic measure and extract the fractal dimension of DLA clusters taking two limits, of vanishingly small probe particle size and of infinitely large size of a D

S. Cht. Mavrodiev, L. Pekevski, B. Vachev

The method is proposed for estimation of regional CO2 and other greenhouses and pollutants production responcibility. The comparison of CO2 local emissions reduction data with world CO2 atmosphere data will permit easy to judge for overall effect in curbing not only global warming but also chemical polution.

B. F. O. Costa, J. Cieslak, S. M. Dubiel

Debye temperature, $\Theta_D$, of Fe-rich Fe$_{100-x}$Cr$_x$ disordered alloys with $0\le x \le 22.3$ was determined from the temperature dependence of the central shift of M\"ossbauer spectra recorded in the temperature range of 60 -- 300 K. Its compositional dependence shows a maximum at $x \approx 5$ with a relative increase of $\sim 30$% compared to a pu

S. Fournais, A. Kachmar

We provide a leading order semiclassical asymptotics of the energy of bound states for magnetic Neumann Schrödinger operators in two dimensional (exterior) domains with smooth boundaries. The asymptotics is valid all the way up to the bottom of the essential spectrum. When the spectral parameter is varied near the value where bound states become allowed in t

Gordon I. Ogilvie, Barbara T. Ferreira

Accretion discs around black holes in X-ray binary stars are warped if the spin axis of the black hole is not perpendicular to the binary orbital plane. They can also become eccentric through an instability involving a resonance with the binary orbit. Depending on the thickness of the disc and the efficiency of dissipative processes, these global deformation

Siegfried Echterhoff, Ryszard Nest, Herve Oyono-Oyono

We study an analogue of fibrations of topological spaces with the homotopy lifting property in the setting of C*-algebra bundles. We then derive an analogue of the Leray-Serre spectral sequence to compute the K-theory of the fibration in terms of the cohomology of the base and the K-theory of the fibres. We present many examples which show that fibrations wi

Barbara T. Ferreira, Gordon I. Ogilvie

High-frequency quasi-periodic oscillations detected in the light curves of black hole candidates can, according to one model, be identified with hydrodynamic oscillations of the accretion disc. We describe a non-linear coupling mechanism, suggested by Kato, through which inertial waves trapped in the inner regions of accretion discs around black holes are ex

Giovanni Alessandrini, Antonino Morassi, Edi Rosset, Sergio Vessella

We prove doubling inequalities for solutions of elliptic systems with an iterated Laplacian as diagonal principal part and for solutions of the Lame&#39; system of isotropic linearized elasticity. These inequalities depend on global properties of the solutions.

Valentin Ovsienko

We describe the main algebraic and geometric properties of the class of algebras introduced in [arXiv:0705.1629]. We discuss their origins in symplectic geometry and associative algebra, and the notions of cohomology and representations. We formulate classification theorems and give a number of examples.

Daniel Boer, Andre Utermann, Erik Wessels

We demonstrate that the RHIC data for hadron production in d-Au collisions for all available rapidities are compatible with geometric scaling. In order to establish the presence of scaling violations expected from small-x evolution a much larger range in transverse momentum and rapidity needs to be probed. We show that the fall-off of the transverse momentum

Siegfried Echterhoff, Ryszard Nest, Herve Oyono-Oyono

In this paper we study continuous bundles of C*-algebras which are non-commutative analogues of principal torus bundles. We show that all such bundles, although in general being very far away from being locally trivial bundles, are at least locally trivial with respect to a suitable bundle version of bivariant K-theory (denoted RKK-theory) due to Kasparov. U

H. Cao, A. Gukasov, I. Mirebeau, P. Bonville

We have studied the field induced magnetic structures in the spin liquid Tb$_2$Ti$_2$O$_7$, in a wide temperature (0.3$<$$T$$<$270 K) and field (0$<$$H$$<$7 T) range, by single crystal neutron diffraction with $\bf{H}$ // [110] axis. We combined unpolarized neutron data with polarized ones, analyzed within the local susceptibility model. A ferromagnetic-like

M. V. Feigel&#39;man, M. A. Skvortsov, K. S. Tikhonov

We propose a way of making graphene superconductive by putting on it small superconductive islands which cover a tiny fraction of graphene area. We show that the critical temperature, T_c, can reach several Kelvins at the experimentally accessible range of parameters. At low temperatures, T<<T_c, and zero magnetic field, the density of states is characterize

C. Foellmi, P. -O. Petrucci, J. Ferreira, G. Henri

Based on a dynamical model describing how stationary, powerful and self-collimated jets are being launched from a magnetized disk, we build a consistent disk+jet microquasar picture. Our disk is a new type of disk solution called the Jet Emitting Disk (JED), and whose characteristics are directly constrained by the presence of a jet. We assume a one-temperat

V. N. Mantsevich, N. S. Maslova

We report the results of theoretical investigations of tunneling current noise spectra in a wide range of applied bias voltage. Localized states of individual impurity atoms play an important role in tunneling current noise formation. It was found that switching &#34;on&#34; and &#34;off&#34; of Coulomb interaction of conduction electrons with two charged lo

E. J. Copeland, D. J. Mulryne, N. J. Nunes, M. Shaeri

We investigate the behaviour of tensor fluctuations in Loop Quantum Cosmology, focusing on a class of scaling solutions which admit a near scale-invariant scalar field power spectrum. We obtain the spectral index of the gravitational field perturbations, and find a strong blue tilt in the power spectrum with $n_t \approx 2$. The amplitude of tensor modes are

Valentina Forini, Matteo Beccaria

In this contribution it is shown how closed formulas for anomalous dimensions of two classes of operators in N=4 SYM can be derived, either by investigating the numerics or on the basis of QCD-inspired assumptions. We discuss the case of twist three "gauge" operators in which a complete proof of reciprocity can be carried out.

Francesca Catino, Matteo Beccaria

The long range Bethe Ansatz solution of the mixing problem in N=4 SYM allows to compute in a very efficient way multiloop anomalous dimensions of various composite operators. In the case of sl(2) twist operators it is important to obtain closed expressions for the anomalous dimensions in terms of the Lorentz spin. Conjectures are available altough analytical

B. Goldman, H. Bouy, M. R. Zapatero Osorio, M. B. Stumpf

Current atmospheric models cannot reproduce some of the characteristics of the transition between the L dwarfs with cloudy atmospheres and the T dwarfs with dust-depleted photospheres. It has been proposed that a majority of the L/T transition brown dwarfs could actually be a combinaison of a cloudy L dwarf and a clear T dwarf. Indeed binarity seems to occur

Adrian S. Lewis, C. H. Jeffrey Pang

To minimize or upper-bound the value of a function &#34;robustly&#34;, we might instead minimize or upper-bound the &#34;epsilon-robust regularization&#34;, defined as the map from a point to the maximum value of the function within an epsilon-radius. This regularization may be easy to compute: convex quadratics lead to semidefinite-representable regularizat

Shi Huang

Numbers (positive integers) are the most fundamental creatures of the human mind and the foundation to the scientific understanding of nature. Some mathematicians have suspected a link between prime numbers and secrets of creation. Understanding creativity may help resolve the deepest mysteries of primes. The algorithm that programs the mind and makes the mi

G. Morlino, E. Amato, P. Blasi

We calculate the flux of non-thermal radiations from the supernova remnant RX J1713.7-3946 in the context of the non-linear theory of particle acceleration at shocks, which allows us to take into account self-consistently the dynamical reaction of the accelerated particles, the generation of magnetic fields in the shock proximity and the dynamical reaction o

Samuel N. Cohen, Robert J. Elliott, Charles E. M. Pearce

This paper studies the set of $n\times n$ matrices for which all row and column sums equal zero. By representing these matrices in a lower dimensional space, it is shown that this set is closed under addition and multiplication, and furthermore is isomorphic to the set of arbitrary $(n-1)\times (n-1)$ matrices. The Moore-Penrose pseudoinverse corresponds wit

Jonathan Reynolds

Given a rational point on a curve in a rational isogeny class, a natural question concerns the field of definition of its pre-images. The multiplication by m endomorphism is a powerful and much-used tool. The pre-images for this map are found by factorizing a monic polynomial of degree m^2. For m = 2, Everest and King gave examples where the existence of a q

Vladimir Baranovsky

Let X be a proper scheme over a field k which satisfies Serre&#39;s condition S2 and G a reductive group over k. We prove that the functor of principal G-bundles defined away from a non-fixed closed subset in X of codimension at least 3, is an algebraic stack in the sense of Artin.

R. N. Bhowmik, Asok Poddar, R. Ranganathan, Chandan Majumdar

We study the ferromagnetism of La0.67Ca0.33MnO3 in bulk polycrystalline, nanocrystalline and amorphous phase. The structural change from crystalline phase to amorphous phase exhibited a systematic decrease of TC(paramagnetic to ferromagnetic transition temperature) and spontaneous magnetization (MS). The experimental results suggested few more features, e.g.

Margaret Beck, C. Eugene Wayne

The large-time behavior of solutions to Burgers equation with small viscosity is described using invariant manifolds. In particular, a geometric explanation is provided for a phenomenon known as metastability, which in the present context means that solutions spend a very long time near the family of solutions known as diffusive N-waves before finally conver

Shahar Hod

The influential theorems of Hawking and Penrose demonstrate that spacetime singularities are ubiquitous features of general relativity, Einstein&#39;s theory of gravity. The utility of classical general relativity in describing gravitational phenomena is maintained by the cosmic censorship principle. This conjecture, whose validity is still one of the most i

J. Yang, L. I. Gurvits, A. P. Lobanov, S. Frey

We investigate the frequency-dependent radio properties of the jet of the luminous high-redshift (z = 3.2) radio quasar PKS 1402+044 (J1405+0415) by means of radio interferometric observations. The observational data were obtained with the VLBI Space Observatory Programme (VSOP) at 1.6 and 5 GHz, supplemented by other multi-frequency observations with the Ve

Scott Simon

We explore the convergence of Kergin interpolation polynomials of holomorphic functions in Banach spaces, which need not be of bounded type. We also investigate a case where the Kergin series diverges.

Alvaro Salas

In this paper we prove the correctness of Dijkstra&#39;s algorithm. We also discuss it and at the end we show an application.

A. M. Sukhovoj, V. A. Khitrov, B. E. Crawford, S. L. Stephenson

To further study the &#34;pygmy&#34; resonance phenomena in the photon strength function, we reanalyzed the two-step cascade data for the target nucleus $^{197}$Au using the Dubna group approach. The range of obtained values allows for meaningful conclusions: the level density at low excitation energy shows a step-like behavior; the electric dipole photon st

Yong S. Joe, Vanik E. Mkrtchian, Sun H. Lee

We analyze bound states of an electron in the field of a positively charged nanoshell. We find that the binding and excitation energies of the system decrease when the radius of the nanoshell increases. We also show that the ground and the first excited states of this system have remarkably the same properties of the highly excited Rydberg states of a hydrog

Shona Yu

----- Please see the pdf file for the actual abstract and important remarks, which could not be put here due to the arXiv length restrictions. ----- This thesis presents a study of the cyclotomic BMW (Birman-Murakami-Wenzl) algebras, introduced by Haring-Oldenburg as a generalization of the BMW algebras associated with the cyclotomic Hecke algebras of type G

Salim Y. El Rouayheb, Alex Sprintson, Costas N. Georghiades

The \emph{index coding} problem has recently attracted a significant attention from the research community due to its theoretical significance and applications in wireless ad-hoc networks. An instance of the index coding problem includes a sender that holds a set of information messages $X=\{x_1,...,x_k\}$ and a set of receivers $R$. Each receiver $ρ=(x,H)\i

Daniel Chan, Rajesh Kulkarni

Maximal orders of rank 4 on the projective plane, ramified on a smooth plane quartic are examples of exotic del Pezzo orders. We compute the possible Chern classes for line bundles on such orders and show the moduli space of line bundles with minimal second Chern class is either a point or a smooth genus two curve.

Kwanghyun Jo, Youngman Kim, Hyun Kyu Lee, Sang-Jin Sin

We study the quark number susceptibility, an indicator of QCD phase transition, in the hard wall and soft wall models of hQCD. We find that the susceptibilities in both models are the same, jumping up at the deconfinement phase transition temperature. We also find that the diffusion constant in the soft wall model is enhanced compared to the one in the hard

Andrew A. West, Gibor Basri

We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most are inactive at a spectral type where H-alpha emission has previously seen to be very common. We used the cross-correlation technique

Adriano Garsia, Gregg Musiker, Nolan Wallach, Guoce Xin

This work lies across three areas (in the title) of investigation that are by themselves of independent interest. A problem that arose in quantum computing led us to a link that tied these areas together. This link consists of a single formal power series with a multifaced interpretation. The deeper exploration of this link yielded results as well as methods

Evans M. Harrell, Selma Yildirim Yolcu

We consider the pseudodifferential operators $H_{m,Ω}$ associated by the prescriptions of quantum mechanics to the Klein-Gordon Hamiltonian $\sqrt{|{\bf P}|^2+m^2}$ when restricted to a compact domain $Ω$ in ${\mathbb R}^d$. When the mass $m$ is 0 the operator $H_{0,Ω}$ coincides with the generator of the Cauchy stochastic process with a killing condition on

Mikio Murata

All $q$-Painlevé equations which are obtained from the $q$-analog of the sixth Painlevé equation are expressed in a Lax formalism. They are characterized by the data of the associated linear $q$-difference equations. The degeneration pattern from the $q$-Painlevé equation of type $A_2$ is also presented.

Sayuri L Prior, G S Da Costa, Stefan C Keller, Simon J Murphy

A subset of the RR Lyrae (RRL) candidates identified from the Southern Edgeworth-Kuiper Belt Object (SEKBO) survey data has been followed up photometrically (n=106) and spectroscopically (n=51). Period and light curve fitting reveals a 24 +/_ 7% contamination of SEKBO survey data by non-RRLs. This paper focuses on the region of the Virgo Stellar Stream (VSS)

M. Kriener, T. Muranaka, J. Kato, Z. A. Ren

The discoveries of superconductivity in heavily boron-doped diamond (C:B) in 2004 and silicon (Si:B) in 2006 renew the interest in the superconducting state of semiconductors. Charge-carrier doping of wide-gap semiconductors leads to a metallic phase from which upon further doping superconductivity can emerge. Recently, we discovered superconductivity in a c

Jiangyong Jia

We review the di-hadron correlation results from RHIC. A consistent physical picture was constructed based on the correlation landscape in $p_T$, $Δϕ$, $Δη$ and particle species. We show that the data are consistent with competition between fragmentation of survived jets and response of the medium to quenched jets. At intermediate $p_T$ where the medium resp

T. Sasaki, N. Yoneyama, Y. Nakamura, N. Kobayashi

We investigated the infrared optical spectra of an organic dimer Mott insulator $κ$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Cl, which was irradiated with X-rays. We observed that the irradiation caused a large spectral weight transfer from the mid-infrared region, where interband transitions in the dimer and Mott-Hubbard bands take place, to a Drude part in a low-ene

F. Mehmood, A. Kara, T. S. Rahman, C. R. Henry

Our ab initio calculations of CO adsorption energies on low miller index (111), (100), stepped (211), and kinked (532) gold surfaces show a strong dependence on local coordination with a reduction in Au atom coordination leading to higher binding energies. We find trends in adsorption energies to be similar to those reported in experiments and calculations f

M. C. Martín, C. E. Cappa, G. A. Romero

In our search for interstellar bubbles around massive stars we analyze the environs of the O-type stars HD 38666, HD 124979, HD 163758, and HD 171589. The location of the stars, which are placed far from the galactic plane, favors the formation of large wind bubbles. We investigate the distribution of the neutral and ionized gas based on HI, CO, and radio co

Conrad Shyu, F. Marty Ytreberg

This report presents the application of polynomial regression for estimating free energy differences using thermodynamic integration. We employ linear regression to construct a polynomial that optimally fits the thermodynamic integration data, and thus reduces the bias and uncertainty of the resulting free energy estimate. Two test systems with analytical so

W. Liu, S. V. Lototsky

A parameter estimation problem is considered for a one-dimensional stochastic wave equation driven by additive space-time Gaussian white noise. The estimator is of spectral type and utilizes a finite number of the spatial Fourier coefficients of the solution. The asymptotic properties of the estimator are studied as the number of the Fourier coefficients inc

Gillian Wilson, Adam Muzzin, H. K. C. Yee, Mark Lacy

The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z&#39;-passband imaging survey, consisting of deep (z&#39; ~ 24 AB) observations made from both hemispheres using the CFHT 3.6m and CTIO 4m telescopes. The survey was designed with the primary aim of detecting galaxy clusters at z >~ 1. In tandem with pre-existing 3.6um observations from

Robert N. Hodgkinson

Higgs singlet superfields, usually present in extensions of the Minimal Supersymmetric Standard Model (MSSM) which address the $μ$-problem, such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and the Minimal Nonminimal Supersymmetric Standard Model (mnSSM), can have significant contributions to $B$-meson flavour-changing neutral current observa

Mike Jarvis, Paul Schechter, Bhuvnesh Jain

In weak lensing investigations, galaxy shapes are deconvolved for the effects of the point spread function (PSF) using stellar images. In this paper we use physical models of the telescope optics to understand the spatial variation of the PSF in the image plane. We introduce a set of parameters to model the key aberrations, which include defocus, focal plane

Mark Dijkstra, Zoltan Haiman, Andrei Mesinger, Stuart Wyithe

The earliest generation of stars and black holes must have established an early &#39;Lyman-Werner&#39; background (LWB) at high redshift, prior to the epoch of reionization. Because of the long mean free path of photons with energies E<13.6 eV, the LWB was nearly uniform. However, some variation in the LWB is expected due to the discrete nature of the source

Adam Muzzin, Gillian Wilson, H. K. C. Yee, Henk Hoekstra

The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z&#39;-band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large homogeneously-selected sample of massive clusters at z > 1 using an infrared adaptation of the cluster red-sequence method. We present an overview of the northern component of the

Anais Rassat, Adam Amara, Luca Amendola, Francisco J. Castander

The Baryon Acoustic Oscillations (BAOs) or baryon wiggles which are present in the galaxy power spectrum at scales 100-150Mpc/h are powerful features with which to constrain cosmology. The potential of these probes is such that these are now included as primary science goals in the planning of several future galaxy surveys. However, there is not a uniquely d