March 2006 arXiv papers — page 30

Matt Kerr

Starting from the candidate Bloch-Beilinson filtration on Chow groups of 0-cycles constructed by J. Lewis, we develop and describe geometrically a series of Hodge-theoretic invariants defined on the graded pieces. Explicit formulas (in terms of currents and membrane integrals) are given for certain quotients of the invariants, with applications to 0-cycles o

Eric C. Rowell

Modular tensor categories are generalizations of the representation categories of quantum groups at roots of unity axiomatizing the properties necessary to produce 3-dimensional TQFTs. Although other constructions have since been found, quantum groups remain the most prolific source. Recently proposed applications to quantum computing have provided an impetu

Susumu Oda

This article has been withdrown by the author.

J. Grabowski, D. Iglesias, J. C. Marrero, E. Padrón

We study affine Jacobi structures on an affine bundle $π:A\to M$, i.e. Jacobi brackets that close on affine functions. We prove that there is a one-to-one correspondence between affine Jacobi structures on $A$ and Lie algebroid structures on the vector bundle $A^+=\bigcup_{p\in M}Aff(A_p,\R)$ of affine functionals. Some examples and applications, also for th

Andrew Hodges

We study the scattering of eight gauge fields, and give all the tree-level amplitudes in the helicity-conserved sector. New symmetries are noted, suggesting that significant further simplification can be achieved.

K. Pohlmeyer

The purpose of the present paper is the communication of some results and observations which shed new light on the algebraic structure of the algebra of string observables both in the classical and in the quantum theory.

Christian Saemann

In this thesis, we report on results in non-anticommutative field theory and twistor string theory, trying to be self-contained. We first review the construction of non-anticommutative N=4 super Yang-Mills theory and discuss a Drinfeld-twist which allows to regain a twisted supersymmetry in the non-anticommutative setting. This symmetry then leads to twisted

Machiko Hatsuda, Shun'ya Mizoguchi

We obtain sets of infinite number of conserved nonlocal charges of strings in a flat space and pp-wave backgrounds, and compare them before and after T-duality transformation. In the flat background the set of nonlocal charges is the same before and after the T-duality transformation with interchanging odd and even-order charges. In the IIB pp-wave backgroun

A. Boulahoual, M. B. Sedra

We introduce in this short note some aspects of the Moyal momentum algebra that we call the Das-Popowicz Mm algebra. Our interest on this algebra is motivated by the central role that it can play in the formulation of integrable models and in higher conformal spin theories.

Alfonso R. Zerwekh

In this paper, we address the universality problem in the mass-mixing representation of vector meson dominance. First we stress the importance of using physical (mass eigenstate) fields in order to get the correct $q^2$ dependence of the pion form factor. Then we show that, when a direct coupling of the (proto-)photon to the pions is included, it is not nece

D. Cronin-Hennessy, CLEO Collaboration

Using the current world&#39;s largest data sample of psi(3770) decays, we present results of a search for the non-DDbar decay psi(3770) -> KsKl. We find no signal, and obtain an upper limit of Sigma(psi(3770) -> KsKl) < 0.07 pb at 90% confidence level (CL). Our result tests a theoretical prediction for the upper bound on B(psi(3770) -> KsKl) based on a charm

Chuanlei Liu

Recent results on the properties of the hadronic final state at the HERA collider are presented. Strangeness production and correlations have been studied in the laboratory system for deep inelastic scattering (DIS). Inclusive $K^0_S$, $Λ$ and $\barΛ$ production has been measured and compared to Monte Carlo model calculations. No significant $Λ$ to $\barΛ$ p

Gianluca Cruciani

Modelling the free fall (and radiative phenomenology) of a massive particle, charged or not, in a static and spherically symmetric black hole is a classic, good relativistic dare that produced a remarkable series of papers, mainly in the seventies of the past century. Some formal topics about the mathematical machinery required to perform the task are unfort

V. Bozza, M. Sereno

We investigate the strong deflection limit of gravitational lensing by a Schwarzschild black hole embedded in an external gravitational field. The study of this model, analogous to the Chang & Refsdal lens in the weak deflection limit, is important to evaluate the gravitational perturbations on the relativistic images that appear in proximity of supermassive

Samuel L. Braunstein, Arun K. Pati

The black-hole information paradox has fueled a fascinating effort to reconcile the predictions of general relativity and those of quantum mechanics. Gravitational considerations teach us that black holes must trap everything that falls into them. Quantum mechanically the mass of a black hole leaks away as featureless (Hawking) radiation, but if the black ho

Charles W. Misner

This is a study of the behavior of wave equations in conformally compactified spacetimes suited to the use of computational boundaries beyond Scri+. There light cones may be adjusted for computational convenience and/or Scri+ may be approximated by a &#34;proto-Scri&#34; spacelike hypersurface just outside a de Sitter horizon. One expects a numerical impleme

Nicolai Kuntze, Andreas U. Schmidt

Horizontal integration of access technologies to networks and services should be accompanied by some kind of convergence of authentication technologies. The missing link for the federation of user identities across the technological boundaries separating authentication methods can be provided by trusted computing platforms. The concept of establishing transi

Heide Gluesing-Luerssen, Gert Schneider

We will study convolutional codes with the help of state space realizations. It will be shown that two such minimal realizations belong to the same code if and only if they are equivalent under the full state feedback group. This result will be used in order to prove that two codes with positive Forney indices are monomially equivalent if and only if they sh

Binh Minh Bui Xuan, Michel Habib, Vincent Limouzy, Fabien De Montgolfier

In this paper, a new general decomposition theory inspired from modular graph decomposition is presented. Our main result shows that, within this general theory, most of the nice algorithmic tools developed for modular decomposition are still efficient. This theory not only unifies the usual modular decomposition generalisations such as modular decomposition

G. Gutin, A. Rafiey, S. Szeider, A. Yeo

A linear arrangement (LA) is an assignment of distinct integers to the vertices of a graph. The cost of an LA is the sum of lengths of the edges of the graph, where the length of an edge is defined as the absolute value of the difference of the integers assigned to its ends. For many application one hopes to find an LA with small cost. However, it is a class

A. A. Peña, R. García-Rojo, H. J. Herrmann

We study by means of molecular dynamics simulations of periodic shear cells, the influence of particle shape on the global mechanical behavior of dense granular media. Results at macro-mechanical level show that for large shear deformation samples with elongated particles, independent of their initial orientation, reach the same stationary value for both she

F. S. Bergeret, A. Levy Yeyati, A. Martin-Rodero

We analyze the magnetic and transport properties of a double quantum dot coupled to superconducting leads. In addition to the possible phase transition to a $π$ state, already present in the single dot case, this system exhibits a richer magnetic behavior due to the competition between Kondo and inter-dot antiferromagnetic coupling. We obtain results for the

J. C. Flores, Mauro Bologna, K. J. Chandía, Constantino A. Utreras Díaz

A wavefront solution for quantum (capacitively coupled) transmission lines with charge discreteness (PRB {\bf 64}, 235309 (2001)) is proposed for the first time. The nonlinearity of the system becomes deeply related to charge discreteness. The wavefront velocity is found to depend on a step discontinuity on the (pseudo) flux variable, $f$, displaying allowed

M. Sepliarksky, Z. Wu, A. Asthagiri, R. E. Cohen

We have developed a shell model potential to describe PbTiO3 and PbMg1/3Nb2/3O3 (PMN) by fitting to first-principles results. At zero pressure, the model reproduces the temperature behavior of PbTiO3, but with a smaller transition temperature than experimentally observed. We then fit a shell model potential for the complex PMN based on the transferability of

Manuel I. Marques, Carmen Arago, Julio A. Gonzalo

It has been known for a long time that the low temperature behavior shown by the dielectric constant of quantum paraelectric $SrTiO_{3}$ can not be fitted properly by Barrett&#39;s formula using a single zero point energy or saturation temperature ($T_{1}$). As it was originally shown [K. A. Müller and H. Burkard, Phys. Rev. B {\bf 19}, 3593 (1979)] a crosso

D. R. Otomar, I. L. Menezes-Sobrinho, M. S Couto

In this work, we present an experimental investigation of the fuse model. Our main goal was to study the influence of the disorder on the fracture process. The experimental apparatus used consisted of an $L\times L$ square lattice with fuses placed on each bond of the lattice. Two types of materials were used as fuses: copper and steel wool wires. The lattic

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

The localization kinetics of a regular block-copolymer of total length $N$ and block size $M$ at a selective liquid-liquid interface is studied in the limit of strong segregation between hydrophobic and polar segments in the chain. We propose a simple analytic theory based on scaling arguments which describes the relaxation of the initial coil into a flat-sh

V. Tsurkan, J. Hemberger, A. Krimmel, H. -A. Krug von Nidda

A detailed study of poly- and single crystalline samples of the normal spinel HgCr2S4 is reported. The structural refinement reveals enhanced values of the atomic displacements suggesting closeness to a structural instability. Magnetization, electron-spin resonance and specific-heat studies document strong ferromagnetic fluctuations close to 50 K and the occ

Filippo Radicchi, Hildegard Meyer-Ortmanns

We study Kuramoto oscillators, driven by one pacemaker, on $d$-dimensional regular topologies with nearest neighbor interactions. We derive the analytical expressions for the common frequency in the case of phase-locked motion and for the critical frequency of the pacemaker, placed at an arbitrary position in the lattice, so that above the critical frequency

Lucia Canova, Jozef Strecka, Michal Jascur

Ground-state and finite-temperature properties of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains are examined within an exact analytical approach based on the generalized decoration-iteration map. A particular emphasis is laid on the investigation of the effect of geometric frustration, which is generated by the competition between Heisenberg-

T. K. Kopec

The concept of topological excitations and the related ground state degeneracy are employed to establish an effective theory of the superconducting state evolving from the Mott insulator for high-Tc cuprates. Casting the Coulomb interaction in terms of composite-fermions via the gauge flux attachment facility, we show that instanton events in the Matsubara &

K. Okazaki, S. Sugai, Y. Muraoka, Z. Hiroi

We have investigated the charge dynamics of VO2 by optical reflectivity measurements. Optical conductivity clearly shows a metal-insulator transition. In the metallic phase, a broad Drude-like structure is observed. On the other hand, in the insulating phase, a broad peak structure around 1.3 eV is observed. It is found that this broad structure observed in

Junko Takahashi, Shuichi Tasaki

Electron transport through a strongly correlated quantum dot (QD) embedded in an Aharonov-Bohm (AB) ring is investigated with the aid of the finite-U slave-boson mean-field (SBMF) approach extended to nonequilibrium regime. A nonequilibrium steady state (NESS) of the mean-field Hamiltonian is constructed with the aid of the C*-algebraic approach for studying

Sijmen Gerritsen, Gerrit E. W. Bauer

We describe the effect of interfaces on classical wave propagation through diffusing layered media. A series resistor model for wave energy transport is introduced and we derive a microscopic expression for the interface resistance.

Hikaru Kawamura

Statistical properties of earthquakes are studied both by the analysis of real earthquake catalog of Japan and by numerical computer simulations of the spring-block model in both one and two dimensions. Particular attention is paid to the spatiotemporal correlations of earthquakes, e.g., the recurrence-time distribution or the time evolution before and after

H. Wadati, A. Chikamatsu, M. Takizawa, R. Hashimoto

We have performed an angle-resolved photoemission spectroscopy study of La$_{0.6}$Sr$_{0.4}$FeO$_3$ using {\it in situ} prepared thin films and determined its band structure. The experimental band dispersions could be well explained by an empirical band structure assuming the G-type antiferromagnetic state. However, the Fe 3d bands were found to be shifted d

Yu. G. Pogorelov

A Green function analysis has been developed for quasiparticle spectrum and localized states of a 2D graphene sheet in presence of different types of substitutional disorder, including vacancies. The anomalous character of impurity effects in this system is demonstrated, compared to those in well known doped semiconductors, and explained in terms of conical

Christian Klinke, Jia Chen, Ali Afzali, Phaedon Avouris

We probed the charge transfer interaction between the amine-containing molecules: hydrazine, polyaniline and aminobutyl phosphonic acid, and carbon nanotube field effect transistors (CNTFETs). We successfully converted p-type CNTFETs to n-type and drastically improved the device performance in both the ON- and OFF- transistor states utilizing hydrazine as do

Allan D. Boardman, Larry Velasco, Neil King, Yuriy Rapoport

A vectorial FDTD method is used to present a numerical study of very narrow spatial solitons interacting with the surface of what has become known as a left-handed medium. After a comprehensive discussion of the background and the family of surface modes to be expected on a left-handed material, bounded by dispersion-free right-handed material, it is demonst

Achim Kempf

It is proposed that the Casimir energy of the electromagnetic field in between the layers of cuprate superconductors could significantly contribute to the energy balance in these materials. Since the Casimir energy is strongly dependent on the distance between the layers a corresponding dependence is predicted for the superconducting transition temperatures.

R. A. Barankov, L. S. Levitov

Fermi gas with time-dependent pairing interaction hosts several different dynamical states. Coupling between the collective BCS pairing mode and individual Cooper pair states can make the latter either synchronize or dephase. We describe transition from phase-locked undamped oscillations to Landau-damped dephased oscillations in the collisionless, dissipatio

D. Klauser, W. A. Coish, Daniel Loss

We study spin dynamics for two electrons confined to a double quantum dot under the influence of an oscillating exchange interaction. This leads to driven Rabi oscillations between the $\ket{\uparrow\downarrow}$--state and the $\ket{\downarrow\uparrow}$--state of the two--electron system. The width of the Rabi resonance is proportional to the amplitude of th

Ioana Bena, Francois Coppex, Michel Droz, Paolo Visco

We consider the characterization of the nonequilibrium stationary state of a randomly-driven granular gas in terms of an entropy-production based variational formulation. Enforcing spatial homogeneity, we first consider the temporal stability of the stationary state reached after a transient. In connection, two heuristic albeit physically motivated candidate

Hui Hu, Xia-Ji Liu, Peter D. Drummond

We present theoretical predictions for the equation of state of a harmonically-trapped Fermi gas in the unitary limit. Our calculations rest on a study of the equation of state of a uniform gas using three distinct perturbation schemes, compared to Monte-Carlo results. We show that in experiments the temperature can be usefully calibrated by making use of th

M. A. Reid, C. D. Wilson

We have mapped an approximately 5.5 by 5.5 pc portion of the M17 massive star-forming region in both 850 and 450 micron dust continuum emission using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). The maps reveal more than 100 dusty clumps with deconvolved linear sizes of 0.05--0.2 pc and masses of 0.8--120

Kandis Lea Jessup, John R. Spencer, Roger Yelle

In February 2003, March 2003 and January 2004 Pele plume transmission spectra were obtained during Jupiter transit with Hubble&#39;s Space Telescope Imaging Spectrograph (STIS), using the 0.1 arcsec long slit and the G230LB grating. The STIS spectra covered the 2100-3100 A wavelength region and extended spatially along Io&#39;s limb both northward of Pele. T

Kaori Otsuki, Satoshi Honda, Wako Aoki, Toshitaka Kajino

We report on observations of six giants in the globular cluster M15 (NGC 7078) using the Subaru Telescope to measure neutron-capture elemental abundances. Our abundance analyses based on high-quality blue spectra confirm the star-to-star scatter in the abundances of heavy neutron-capture elements (e.g., Eu), and no significant s-process contribution to them,

J. P. Aufdenberg, A. Merand, V. Coude du Foresto, O. Absil

We have obtained high-precision interferometric measurements of Vega with the CHARA Array and FLUOR beam combiner in the K&#39; band at projected baselines between 103m and 273m. The measured visibility amplitudes beyond the first lobe are significantly weaker than expected for a slowly rotating star characterized by a single effective temperature and surfac

V. V. Neustroev, S. V. Zharikov, R. Michel

We report simultaneous photometric and echelle-spectroscopic observations of the dwarf nova BZ UMa during which we were lucky to catch the system at the onset of an outburst, the development of which we traced in detail from quiescence to early decline. The outburst had a precursor, and was of a short duration (~5 days) with a highly asymmetrical light curve

Clovis Hopman, Tal Alexander

Gravitational waves (GWs) from the inspiral of compact remnants (CRs) into massive black holes (MBHs) will be observable to cosmological distances. While a CR spirals in, 2-body scattering by field stars may cause it to fall into the MBH before reaching a short period orbit that would give an observable signal. As a result, only CRs very near (~0.01 pc) the

John M. O&#39;Meara, Hsiao-Wen Chen, David L. Kaplan

We present initial results from a Magellan telescope program to image galaxies that give rise to damped Lyman absorbers (DLAs) at 1.63 < z_DLA < 2.37. Our program differs from previous efforts in that we target quasars with intervening Lyman limit systems (LLS) along the line of sight at redshift z_LLS > 3.5. The higher-redshift LLS is applied as a blocking

Martin Cohen, Jessica M. Chapman, Rachel M. Deacon, Robert J. Sault

We present radio observations of the unique, recently formed, planetary nebula (PN) associated with a very long-period OH/IR variable star V1018 Sco that is unequivocally still in its asymptoticgiant branch phase. Two regions within the optical nebula are clearly detected in nonthermal radio continuum emission, with radio spectral indices comparable to those

D. J. Pinfield, H. R. A. Jones, P. W. Lucas, T. R. Kendall

Using a simulated disk brown dwarf (BD) population, we find that new large area infrared surveys are expected to identify enough BDs covering wide enough mass--age ranges to potentially measure the mass function down to ~0.03Mo, and the BD formation history out to 10 Gyr, at a level capable of establishing if BD formation follows star formation. We suggest t

Merav Opher, Edward C. Stone, Paulett C. Liewer

We show that that an interstellar magnetic field can produce a north/south asymmetry in solar wind termination shock. Using Voyager 1 and 2 measurements, we suggest that the angle $α$ between the interstellar wind velocity and magnetic field is $30^{\circ} < α< 60^{\circ}$. The distortion of the shock is such that termination shock particles could stream out

Peregrine M. McGehee

The stellar group surrounding the Be (B1Vpe) star 25 Orionis was discovered to be a pre-main-sequence population by the Centro de Investigaciones de Astronomia (CIDA) Orion Variability Survey and subsequent spectroscopy. We analyze Sloan Digital Sky Survey multi-epoch photometry to map the southern extent of the 25 Ori group and to characterize its pre-main-

Bruno Letarte, Vanessa Hill, Pascale Jablonka, Eline Tolstoy

We present a high resolution (R ~ 43000) abundance analysis of a total of nine stars in three of the five globular clusters associated with the nearby Fornax dwarf spheroidal galaxy. These three clusters (1, 2 and 3) trace the oldest, most metal-poor stellar populations in Fornax. We determine abundances of O, Mg, Ca, Ti, Cr, Mn, Fe, Ni, Zn, Y, Ba, La, Nd an

P. D. Dobbie, R. Napiwotzki, M. R. Burleigh, M. A. Barstow

We report the spectroscopic confirmation of four further white dwarf members of Praesepe. This brings the total number of confirmed white dwarf members to eleven making this the second largest collection of these objects in an open cluster identified to date. This number is consistent with the high mass end of the initial mass function of Praesepe being Salp

J. R. Rigby, G. H. Rieke, J. L. Donley, A. Alonso-Herrero

We investigate why half of X-ray--selected active galactic nuclei (AGN) in deep surveys lack signs of accretion in their optical spectra. The majority of these ``optically--dull&#39;&#39; AGN are no more than 6 times fainter than their host galaxies in rest-frame R-band; as such, AGN lines are unlikely to be overwhelmed by stellar continuum in at least half

Paul M. O&#39;Neill, Shai Kaspi, Ari Laor, Kirpal Nandra

We report on two Chandra observations, and a simultaneous Hubble Space Telescope ultraviolet observation, of the dwarf Seyfert 1 galaxy NGC 4395. Each Chandra observation had a duration of ~30 ks, with a separation of ~50 ks. The spectrum was observed to harden between these observations via a scaling down of the soft-band flux. The inter-observation variabi

W. F. Kao

Modified Newtonian dynamics can be considered as an effect derived from a squeezable extra dimension space. The third law of Newtonian dynamics can be managed to remain valid in the 5-space. The critical acceleration parameter $a_0$ appears naturally as the bulk acceleration that has to do with the expanding universe in this setup. A simple toy model is pres

R. S. Schnerr, E. Verdugo, H. F. Henrichs, C. Neiner

We report on attempts to measure the magnetic field of the pulsating B star $ν$ Eridani with the Musicos spectropolarimeter attached to the 2m telescope at the Pic du Midi, France. This object is one of the most extensively studied stars for pulsation modes, and the existence of a magnetic field was suggested from the inequality of the frequency separations

F. E. Schunck, B. Fuchs, E. W. Mielke

A non-topological soliton model with a repulsive scalar self-interaction of the Emden type provides a constant density core,similarly as the empirical Burkert profile of dark matter haloes. As a further test, we derive the gravitational lens properties of our model, in particular, the demarcation curves between `weak&#39; and `strong&#39; lensing. Accordingl

F. K. Hansen, A. J. Banday, H. K. Eriksen, K. M. Gorski

We present a new approach to foreground removal for Cosmic Microwave Background (CMB) maps. Rather than relying on prior knowledge about the foreground components, we first extract the necessary information about them directly from the microwave sky maps by taking differences of temperature maps at different frequencies. These difference maps, which we refer

M. Axelsson, L. Borgonovo, S. Larsson

Building on results from previous studies of Cygnus~X-1, we analyze Rossi X-ray Timing Explorer (RXTE) data taken when the source was in the soft and transitional spectral states. We look at the power spectrum in the 0.01 -- 50 Hz range, using a model consisting of a cut-off power-law and two Lorentzian components. We are able to constrain the relation betwe

E. Jehin, J. Manfroid, D. Hutsemekers, A. L. Cochran

We report on observations of comet 9P/Tempel 1 carried out before, during, and after the NASA DEEP IMPACT event (UT July 4), with the optical spectrometers UVES and HIRES mounted on the telescopes Kueyen of the ESO VLT (Chile) and Keck 1 on Mauna Kea (Hawaii), respectively. A total observing time of about 60 hours, distributed over 15 nights around the impac

Svetozar A. Zhekov, Richard McCray, Kazimierz J. Borkowski, David N. Burrows

We discuss the results from deep Chandra LETG observations of the supernova remnant 1987A (SNR 1987A). We find that a distribution of shocks, spanning the same range of velocities (from 300 to 1700 km/s) as deduced in the first part of our analysis (Zhekov et al. 2005, ApJL, 628, L127), can account for the entire X-ray spectrum of this object. The post-shock

S. Fischer, C. Iserlohe, J. Zuther, T. Bertram

We present near infrared ISAAC VLT observations of nine (0.01<z<0.06) Active Galactic Nuclei selected from the Hamburg/ESO Survey and the Veron-Cetty & Veron catalog. Hydrogen recombination lines Pa$α$ and Br$γ$ are observed in seven of the nine sources of which five show a broad component. In three sources, extended 1-0S(1) rotational-vibrational molecular

S. A. Petrova

Pulsar radio emission is modelled as a sum of two completely polarized non-orthogonal modes with the randomly varying Stokes parameters and intensity ratio. The modes are the result of polarization evolution of the original natural waves in the hot magnetized weakly inhomogeneous plasma of pulsar magnetosphere. In the course of wave mode coupling, the linear

Cécile Barbachoux, Jérome Gariel, Gérard Le Denmat

In a thermodynamical model of cosmological FLRW event horizons for the dark energy (DE), we consider a logarithmic corrective term in the entropy to which corresponds a new term in the DE density. This model of $Λ(t)$ in an interacting two-component cosmology with cold dark matter (DM) as second component leads to a system of coupled equations, yielding, aft

Masaru Ajiki, Yoshiaki Taniguchi, Takashi Murayama, Yasuhiro Shioya

Recently, Zheng et al. (2005) found evidence for an overdensity of galaxies around a radio-loud quasar, SDSS J0836+0054, at z=5.8 (a five arcmin$^2$ region). We have examined our deep optical imaging data (B, V, r&#39;, i&#39;, z&#39;, and NB816) taken with the Suprime-Cam on the Subaru Telescope. The NB816 narrow-band filter (lambda_c = 815 nm and $Δλ= 12$

Douglas C. Leonard, Alexei V. Filippenko, Mohan Ganeshalingam, Franklin J. D. Serduke

An important and perhaps critical clue to the mechanism driving the explosion of massive stars as supernovae is provided by the accumulating evidence for asymmetry in the explosion. Indirect evidence comes from high pulsar velocities, associations of supernovae with long-soft gamma-ray bursts, and asymmetries in late-time emission-line profiles. Spectropolar

M. A. Smith, G. W. Henry, E. Vishniac

We report results of a nine-year monitoring effort on the unusual classical Be with a robotic ground-based (APT) B,V-filtered telescope as well as simultaneous observations in 2004 November with this instrument and the RXTE (X-ray) telescope. Our observations disclosed no correlated optical response to the rapid X-ray flares in this star, nor did the star sh

Matts Roos

Our procedure to obtain best values for cosmological parameters from five recent multiparameter fits is as follows. We first study the values quoted for $r, α_s, w+1 (w_0+1), w_1$ and $Ω_k$, arriving at the conclusion that they do not differ significantly from zero, and their correlations to other parameters are insignificant. In what follows they can be the

H. Andernach, R. Coziol

We use various samples of compact groups (CGs) to examine the types of association CGs have with rich and poor clusters of galaxies at low (z~0.04) and intermediate (z~0.1) redshifts. We find that ~10-20 % of CGs are associated with rich clusters and a much larger fraction with poorer clusters or loose groups. Considering the incompleteness of catalogs of po

François Germinet, Peter D. Hislop, Abel Klein

We prove exponential and dynamical localization for the Schrödinger operator with a nonnegative Poisson random potential at the bottom of the spectrum in any dimension. We also conclude that the eigenvalues in that spectral region of localization have finite multiplicity. We prove similar localization results in a prescribed energy interval at the bottom of

Lesya Bodnarchuk, Igor Burban, Yuriy Drozd, Gert-Martin Greuel

In this paper we give a survey about the classification of vector bundles and torsion free sheaves on degenerations of elliptic curves. Coherent sheaves on singular curves of arithmetic genus one can be studied using the technique of matrix problems or via Fourier-Mukai transforms, both methods are discussed here. Moreover, we include new proofs of some clas

Phung Ho Hai

For a rigid tensor abelian category $T$ over a field $k$ we introduce a notion of a normal quotient $q:T\to Q$. In case $T$ is a Tannaka category, our notion is equivalent to Milne&#39;s notion of a normal quotient. More precisely, if $T$ is the category of finite dimensional representations of a groupoid scheme $G$ over $k$, then $Q$ is equivalent to the re

Bakir Farhi

We present here quantitative versions in 1 dimension of Faltings&#39;theorem according to which the set of the K-rational points (where K is a given number field) of an abelian variety A definied over K, which are close (with respect to a v-adic distance on K) to some K-subvariety X of A, but not belonging to X, is finite. We treat more exactly the case wher

G. V. Vereshchagin, G. Yegorian

The dark energy formula derived by Gurzadyan and Xue which leads to a value fitting the SN data, provides a scaling relation between the physical constants and cosmological parameters and defines a set of cosmological models. In previous works we have considered several of those models and derived the cosmological equations for each case. In this letter, we

M. Asakawa, S. A. Bass, B. Müller

We argue that an expanding quark-gluon plasma has an anomalous viscosity, which arises from interactions with dynamically generated color fields. We derive an expression for the anomalous viscosity in the turbulent plasma domain and apply it to the hydrodynamic expansion phase, when the quark-gluon plasma is near equilibrium. The anomalous viscosity dominate

Stefano Mancini, Simone Severini

Determining whether a quantum state is separable or entangled is a problem of fundamental importance in quantum information science. This is a brief review in which we consider the problem for states in infinite dimensional Hilbert spaces. We show how the problem becomes tractable for a class of Gaussian states.

F. Beukers

We give a proof of the irrationality of the $p$-adic zeta-values $ζ_p(k)$ for $p=2,3$ and $k=2,3$. Such results were recently obtained by F.Calegari as an application of overconvergent $p$-adic modular forms. In this paper we present an approach using classical continued fractions discovered by Stieltjes. In addition we show irrationality of some other $p$-a

Huai-yang Cui

According to the theory of relativity, the 4-vector force acting on a particle is orthogonal to the 4-vector velocity of the particle, but we found that the electromagnetic force of the Maxwell&#39;s theory can not completely satisfy this orthogonality, this incompletion leads us to find that the electromagnetic force has two independent components in the 4

Shu Luo, Zhi-zhong Xing

Taking the standard parametrization of three-flavor neutrino mixing, we carefully examine the evolution of three CP-violating phases $(δ, α^{}_1, α^{}_2)$ with energy scales in the realistic limit $θ^{}_{13} \to 0$. If $m^{}_3$ vanishes, we find that the one-loop renormalization-group equation (RGE) of $δ$ does not diverge and its running has no quasi-fixed

Pablo Mora

In this paper I present an action principle for odd dimensional AdS gravity which consists of introducing another manifold with the same boundary and a very specific boundary term. This new action allows and alternative approach to the regularization of the theory, yielding a finite euclidean action and finite conserved charges. The choice of the boundary te

Benjamin McKay

We prove rigidity of various types of holomorphic parabolic geometry on smooth complex projective varieties.

D. V. Bugg

Ratios of coupling constants for these decays are compared with q-qbar predictions and Jaffe&#39;s 4-quark model. In both models, the predicted ratio g^2(kappa -> K-pi)/ g^2(sigma -> pi-pi) is much too small. Also, for q-qbar, the predicted ratio g^2(kappa -> K-eta &#39;)/g^2(kappa -> K-pi) is much larger than observed. Both models fail for g^2(fo -> KK)/g^2

D. V. Bugg

Data for phi -> gamma (eta-pizero) are analysed using the KK loop model and compared with parameters of a0(980) derived from Crystal Barrel data. The eta-pi mass spectrum agrees closely and the absolute normalisation lies just within errors. However, BES parameters for fo(980) predict a normalisation for phi -> gamma (pizero-pizero) at least a factor 2 lower

Sze Kui Ng

In this paper we propose a quantum gauge system from which we construct generalized Wilson loops which will be as quantum knots. From quantum knots we give a classification table of knots where knots are one-to-one assigned with an integer such that prime knots are bijectively assigned with prime numbers and the prime number 2 corresponds to the trefoil knot

Rumin Wang, G. R. Lu, En-Ke Wang, Ya-Dong Yang

We study the branching ratios, the direct CP asymmetries in $B\to K^{(*)}\bar{K}^{(*)}$ decays and the polarization fractions of $B\to K^{*}\bar{K}^{*}$ decays by employing the QCD factorization in the minimal supersymmetric standard model with R-parity violation. We derive the new upper bounds on the relevant R-parity violating couplings from the latest exp

Jean Bertoin, Ronald A. Doney, Ross A. Maller

We wish to characterise when a Lévy process $X_t$ crosses boundaries like $t^κ$, $κ>0$, in a one or two-sided sense, for small times $t$; thus, we enquire when $\limsup_{t\downarrow 0}|X_t|/t^κ$, $\limsup_{t\downarrow 0}X_t/t^κ$ and/or $\liminf_{t\downarrow 0}X_t/t^κ$ are almost surely (a.s.) finite or infinite. Necessary and sufficient conditions are given

Hiroki Sayama

This essay aims to propose construction theory, a new domain of theoretical research on machine construction, and use it to shed light on a fundamental relationship between living and computational systems. Specifically, we argue that self-replication of von Neumann&#39;s universal constructors holds a close similarity to circular computational processes of

Alexander Woo, Alexander Yong

We present a combinatorial and computational commutative algebra methodology for studying singularities of Schubert varieties of flag manifolds. We define the combinatorial notion of *interval pattern avoidance*. For &#34;reasonable&#34; invariants P of singularities, we geometrically prove that this governs (1) the P-locus of a Schubert variety, and (2) whi

Yujiro Richard Yamada, Charles S. Peskin

A chemical kinetic model of the elongation dynamics of RNA polymerase along a DNA sequence is introduced. The proposed model governs the discrete movement of the RNA polymerase along a DNA template, with no consideration given to elastic effects. The model&#39;s novel concept is a ``look-ahead&#39;&#39; feature, in which nucleotides bind reversibly to the DN

E. A. Huerta, S. Mendoza

We construct a simple accretion model of a rotating pressureless gas sphere onto a Schwarzschild black hole. We show how to build analytic solutions in terms of Jacobi elliptic functions. This construction represents a general relativistic generalisation of the Newtonian accretion model first proposed by Ulrich (1976). In exactly the same form as it occurs f

Yueping Niu, Shangqing Gong

The second-order susceptibility which vanishes in the electric-dipole approximation for an atom is induced by the spontaneously generated coherence. The spontaneously generated coherence considered in a lambda-type atomic system causes an indirect coupling between the lower two levels which acts equivalently as a DC-field and therefore makes possible the exi

S. Y. Chang, V. R. Pandharipande

The ground state energy and pairing gap of the interacting Fermi gases calculated by the {\it ab initio} stochastic method are compared with those estimated from the Bardeen-Cooper-Schrieffer pairing Hamiltonian. We discuss the ingredients of this Hamiltonian in various regimes of interaction strength. In the weakly interacting ($1/ak_F <<0$) regime the BCS

Antonio Alvaro Ranha Neves, Adriana Fontes, Lazaro Aurelio Padilha, Eugenio Rodriguez

Using an analytical expression for an integral involving Bessel and Legendre functions we succeeded to obtain the partial wave decomposition of a general optical beam at an arbitrary location from the origin. We also showed that the solid angle integration will eliminate the radial dependence of the expansion coefficients. The beam shape coefficients obtaine

John W. Clark, Haochen Li

Advances in statistical learning theory present the opportunity to develop statistical models of quantum many-body systems exhibiting remarkable predictive power. The potential of such ``theory-thin&#39;&#39; approaches is illustrated with the application of Support Vector Machines (SVMs) to global prediction of nuclear properties as functions of proton and

G. von Gehlen, N. Iorgov, S. Pakuliak, V. Shadura

The Baxter-Bazhanov-Stroganov model (also known as the τ^(2) model) has attracted much interest because it provides a tool for solving the integrable chiral Z_N-Potts model. It can be formulated as a face spin model or via cyclic L-operators. Using the latter formulation and the Sklyanin-Kharchev-Lebedev approach, we give the explicit derivation of the eigen