December 2004 arXiv papers — page 2

J. H. Debes, S. Sigurdsson, B. Woodgate

We present high contrast images of the hydrogen white dwarf G 29-38 taken in the near infrared with the Hubble Space Telescope and the Gemini North Telescope as part of a high contrast imaging search for substellar objects in orbit around nearby white dwarfs. We review the current limits on planetary companions for G29-38, the only nearby white dwarf with an

Benjamin Grinstein

I give a personal account of the development of the field of heavy quarks. After reviewing the experimental discovery of charm and bottom quarks, I describe how the field's focus shifted towards determination of CKM elements and how this has matured into a precision science.

Mladen Barbic, Axel Scherer

The achievement of three-dimensional atomic resolution magnetic resonance microscopy remains one of the main challenges in the visualization of biological molecules. The prospects for single spin microscopy have come tantalizingly close due to the recent developments in sensitive instrumentation. Despite the single spin detection capability in systems of spa

Marie Ericsson, Daryl Achilles, Julio T. Barreiro, David Branning

Geometric phase may enable inherently fault-tolerant quantum computation. However, due to potential decoherence effects, it is important to understand how such phases arise for {\it mixed} input states. We report the first experiment to measure mixed-state geometric phases in optics, using a Mach-Zehnder interferometer, and polarization mixed states that are

Katarzyna Miakisz, Edward W. Piotrowski, Jan Sladkowski

On grounds of the discussed material, we reason about possible future development of quantum game theory and its impact on information processing and the emerging information society. The idea of quantum artificial intelligence is explained.

Yun-Feng Xiao, Zheng-Fu Han, Jie Gao, Guang-Can Guo

We propose a scheme to create universal Dicke states of n largely detuned atoms through detecting the leaky photons from an optical cavity. The generation of entangled states in our scheme has quasi-unit success probability, so it has potential practicability based on current or near coming laboratory cavity QED technology.

Barak Dayan, Avi pe'er, Asher A. Friesem, Yaron Silberberg

We experimentally demonstrate sum-frequency generation (SFG) with entangled photon-pairs, generating as many as 40,000 SFG photons per second, visible even to the naked eye. The nonclassical nature of the interaction is exhibited by a linear intensity-dependence of the nonlinear process. The key element in our scheme is the generation of an ultrahigh flux of

Carlos Escudero

We study the effect of chemotactic signaling among mesenchymal cells. We show that the particular physiology of the mesenchymal cells allows one-dimensional collapse in contrast to the case of bacteria, and that the mesenchymal morphogenesis represents thus a more complex type of pattern formation than those found in bacterial colonies. We finally compare ou

Carlos Escudero

We study a master equation system modelling a population dynamics problem in a lattice. The problem is the calculation of the minimum size of a refuge that can protect a population from hostile external conditions, the so called critical patch size problem. We analize both cases in which the particles are considered fermions and bosons and show using exact a

V. M. Akulin, V. A. Dubovitskii, A. M. Dykhne, A. G. Rudavets

Globally optimal solution describing a phase conjugated field of Raman scattering on the resonant $B\gets X$ transition of iodine $I_2$ is studied. Maximum optical coherence is found as a top eigenvalue problem. A reversibility theorem has been stated. This provides sufficient conditions for a tightly localized waveform and molecular hologram to exist. A noi

Carlos Escudero

We study the extended hydrodynamics proposed by Philip Rosenau [Phys. Rev. A 40, 7193 (1989)] in the context of a regularization of the Chapman-Enskog expansion. We are able to prove that shock waves appear in finite time in Rosenau's extended Burgers' equation, and we discuss the physical implications of this fact and its connection with a possible

Grzegorz Litak, Arkadiusz Syta, Marek Borowiec

We examine the Mielnikov criterion for transition to chaos in case of one degree of freedom nonlinear oscillator with non symmetric potential. This system subjected to an external periodic force shows homoclinic transition from regular vibrations to chaos just before escape from the potential well. Especially we study the effect of a second resonant excitati

E. V. Ferapontov, K. R. Khusnutdinova, S. P. Tsarev

We characterize non-degenerate Lagrangians of the form $ \int f(u_x, u_y, u_t) dx dy dt $ such that the corresponding Euler-Lagrange equations $ (f_{u_x})_x+ (f_{u_y})_y+ (f_{u_t})_t=0 $ are integrable by the method of hydrodynamic reductions. The integrability conditions constitute an over-determined system of fourth order PDEs for the Lagrangian density $f

Uffe Haagerup, Hanne Schultz, Steen Thorbjornsen

In 1982 Pimsner and Voiculescu computed the K_0- and K_1-groups of the reduced group C*-algebra C*_red(F_k) of the free group F_k on k generators and settled thereby a long standing conjecture: C*_red(F_k) has no projections except for the trivial projections 0 and 1. Later simpler proofs of this conjecture were found by methods from K-theory or from non-com

M. Sellier

The question of interest in the present study is: ``Given a body subject to mechanical loads, how to define the initial geometry so that the deformed one matches precisely a prescribed shape?'' This question is particularly relevant in forming processes where the tolerated mismatch between the deformed and desired geometries may be lower than a Micro

Kamran Divaani-Aazar, Mohammad Ali Esmkhani

This paper centers around Artinianness of the local cohomology of $ZD$-modules. Let $\fa$ be an ideal of a commutative Noetherian ring $R$. The notion of $\fa$-relative Goldie dimension of an $R$-module $M$, as a generalization of that of Goldie dimension is presented. Let $M$ be a $ZD$-module such that $\fa$-relative Goldie dimension of any quotient of $M$

A. Mudrov

Let $G$ be a simple complex classical group and $\g$ its Lie algebra. Let $\U_\hbar(\g)$ be the Drinfeld-Jimbo quantization of the universal enveloping algebra $\U(\g)$. We construct an explicit $\U_\hbar(\g)$-equivariant quantization of conjugacy classes of $G$ with Levi subgroups as the stabilizers.

Ph. Barbe, W. P. McCormick

We establish some asymptotic expansions for infinite weighted convolution of distributions having regular varying tails. Various applications to statistics and probability are developed.

Plamen Stefanov

For various compactly supported perturbations of the Laplacian in odd dimensions $n$, we prove a sharp upper bound of the resonance counting function $N(r)$ of the type $N(r) \le A_n r^n(1+o(1))$ with an explicit constant $A_n$. In a few special cases, we show that this estimate turns into an asymptotic.

Seth Sullivant

We provide a characterization of the compressed lattice polytopes in terms of their facet defining inequalities and we show that every compressed lattice polytope is affinely isomorphic to a 0/1-polytope. As an application, we characterize those graphs whose cut polytopes are compressed and discuss consequences for studying linear programming relaxations in

Joy Ko

We establish a framework to construct a global solution in the space of finite energy to a general form of the Landau-Lifshitz-Gilbert equation in $\mathbb{R}^2$. Our characterization yields a partially regular solution, smooth away from a 2-dimensional locally finite Hausdorff measure set. This construction relies on approximation by discretization, using t

Margaret I. Doig

We construct a one-dimensional deformation retract of the unordered k-point configuration space of a star S. This retract suggests an explicit set of free generators Beta_k for the corresponding braid group of the star B_k and shows that the natural map from B_k-1 to B_k sends Beta_k-1 to Beta_k injectively.

Zhi-Wei Sun

Let G be any group and $a_1G_1,...,a_kG_k (k>1)$ be left cosets in G. In 1974 Herzog and Schönheim conjectured that if $\Cal A=\{a_iG_i\}_{i=1}^k$ is a partition of G then the (finite) indices $n_1=[G:G_1],...,n_k=[G:G_k]$ cannot be distinct. In this paper we show that if $\Cal A$ covers all the elements of G the same times and $G_1,...,G_k$ are subnormal su

P. Marios. Petropoulos

I review some marginal deformations of SU(2) and SL(2,R) Wess-Zumino-Witten models, which are relevant for the investigation of the moduli space of NS5/F1 brane configurations. Particular emphasis is given to the asymmetric deformations, triggered by electric or magnetic fluxes. These exhibit critical values, where the target spaces become exact geometric co

J. M. Pawlowski, D. F. Litim, S. Nedelko, L. von Smekal

We summarise an analysis of the infrared regime of Landau gauge QCD by means of a flow equation approach. The infrared behaviour of gluon and ghost propagators is evaluated. The results provide further evidence for the Kugo-Ojima confinement scenario. We also discuss their relation to results obtained with other functional methods as well as the lattice.

John Baez, Urs Schreiber

Connections and curvings on gerbes are beginning to play a vital role in differential geometry and mathematical physics -- first abelian gerbes, and more recently nonabelian gerbes. These concepts can be elegantly understood using the concept of `2-bundle' recently introduced by Bartels. A 2-bundle is a generalization of a bundle in which the fibers are

Davide Gaiotto, Andrew Strominger, Xi Yin

In recent work, the superconformal quantum mechanics describing D0 branes in the AdS_2xS^2xCY_3 attractor geometry of a Calabi-Yau black hole with D4 brane charges p^A has been constructed and found to contain a large degeneracy of chiral primary bound states. In this paper it is shown that the asymptotic growth of chiral primaries for N D0 branes exactly ma

M. Loewe, S. Mendizabal, J. C. Rojas

We analyze the stability of different topological solutions in Quantum Field Theory when an isospin chemical potential $μ$ is included. We work in the limit when temperature vanishes. We find that static vortex solutions in $2+1D$ do exist. However, the 't Hooft-Polyakov monopole in $3+1D$ is no longer stable, as soon as the chemical potential acquires a

Nikolaos Kidonakis

I present a calculation of QCD radiative corrections to charged Higgs production via the process bg -> tH-. I show that the cross section is dominated by soft-gluon corrections, which are computed through next-to-next-to-leading order. Results for charged Higgs production at the LHC are presented, including the dependence of the cross section on the charged

A. J. Buchmann

The C2/M1 ratio of the electromagnetic N->Delta(1232) transition, which is important for determining the geometric shape of the nucleon, is shown to be related to the neutron elastic form factor ratio G_C^n/G_M^n. The proposed relation holds with good accuracy for the entire range of momentum transfers where data are available.

A. V. Efremov, K. Goeke, P. Schweitzer

A review is given on single spin asymmetries in deep inelastic semi-inclusive scattering (SIDIS) and their possible theoretical understanding in the framework of QCD-induced factorization approach, wherefore predictions for transversity from the chiral quark soliton model are used. Arising difficulties to interpret most recent SIDIS data, and the possibility

A. Bartl, S. Hesselbach

We first discuss the basic features of electroweak 1-loop corrections in the Standard Model. We also give a short and elementary review on Higgs boson searches, grand unification, supersymmetry and extra dimensions.

Benjamin Grinstein

Conference Summary at FPCP04

Benjamin Grinstein

We review the theory of the determination of the CKM elements Vcb and Vub. Particular attention is paid to the determination of Vcb through inclusive semileptonic B decays to charm using a moment analysis, since this has shown most progress recently. A precise method for the determination of Vub via exclusive decays is described.

M. H. Reno

Next-to-leading order QCD corrections, order 1 GeV mass corrections and the role of a strangeness asymmetry and isospin violation in the x dependence of the parton distribution functions are evaluated in the context of the neutrino-nucleon cross section. Their contributions to evaluations of the weak mixing angle using the Paschos-Wolfenstein relation are di

K. A. Bronnikov, E. A. Tagirov

Fock representations are constructed for a free scalar field in the closed and quasi-Euclidean isotropic cosmological models. Invariance of their cyclic vector (vacuum) under isometries and the correspondence principle single out a class of unitarily equivalent representations.

Giovanni Amelino-Camelia

After a brief review of the first phase of development of Quantum-Gravity Phenomenology, I argue that this research line is now ready to enter a more advanced phase: while at first it was legitimate to resort to heuristic order-of-magnitude estimates, which were sufficient to establish that sensitivity to Planck-scale effects can be achieved, we should now r

Douglas J. Shaw, John D. Barrow

We extend the theory of Kimberly and Magueijo for the spacetime variation of the electroweak couplings in the unified Glashow-Salam-Weinberg model of the electroweak interaction to include quantum corrections. We derive the effective quantum-corrected dilaton evolution equations in the presence of a background cosmological matter density that is composed of

M. Blagojevic, B. Cvetkovic

We study the canonical structure of the topological 3D gravity with torsion, assuming the anti-de Sitter asymptotic conditions. It is shown that the Poisson bracket algebra of the canonical generators has the form of two independent Virasoro algebras with classical central charges. In contrast to the case of general relativity with a cosmological constant, t

Plamen Fiziev

Utilizing various gauges of the radial coordinate we give a description of static spherically symmetric space-times with point singularity at the center and vacuum outside the singularity. We show that in general relativity (GR) there exist a two-parameters family of such solutions to the Einstein equations which are physically distinguishable but only some

J. Hwang, H. Noh

We present cosmological perturbation theory based on generalized gravity theories including string theory correction terms and a tachyonic complication. The classical evolution as well as the quantum generation processes in these variety of gravity theories are presented in unified forms. These apply both to the scalar- and tensor-type perturbations. Analyse

P. P. Fiziev

We show that Einstein equations are compatible with the presence of massive point particles and find corresponding two parameter family of their solutions which depends on the bare mechanical mass $M_0>0$ and the Keplerian mass $M<M_0$ of the point source of gravity. The global analytical properties of these solutions in the complex plane define a unique pre

Shmuel Vagner

The rapid growth of the internet in general and of bandwidth capacity at internet clients in particular poses increasing computation and bandwidth demands on internet servers. Internet access technologies like ADSL [DSL], Cable Modem and Wireless modem allow internet clients to access the internet with orders of magnitude more bandwidth than using traditiona

Chiranjeeb Buragohain, Divyakant Agrawal, Subhash Suri

Wireless sensor networks offer the potential to span and monitor large geographical areas inexpensively. Sensor network databases like TinyDB are the dominant architectures to extract and manage data in such networks. Since sensors have significant power constraints (battery life), and high communication costs, design of energy efficient communication algori

Pierre Andrews, Martin Rajman

Contrarily to standard approaches to topic annotation, the technique used in this work does not centrally rely on some sort of -- possibly statistical -- keyword extraction. In fact, the proposed annotation algorithm uses a large scale semantic database -- the EDR Electronic Dictionary -- that provides a concept hierarchy based on hyponym and hypernym relati

P. D. Gujrati, F. Semerianov

Configurational states that are to be associated, according to Goldstein, with the basins in the potential energy landscape cannot be characterized by any particular basin identifier such as the basin minima, the lowest barrier, the most probable energy barrier, etc. since the basin free energy turns out to be independent of the energies of these identifiers

P. D. Gujrati

We introduce the concept of stationary metastable states (SMS&#39;s) in the presence of another more stable state. The stationary nature allows us to study SMS&#39;s by using a restricted partition function formalism as advocated by Penrose and Lebowitz and requires continuing the free energy. The formalism ensures that SMS free energy satisfies the requirem

Zhaohui Zhong, Ying Fang, Wei Lu, Charles M. Lieber

We report low-temperature electrical transport studies of molecule-scale silicon nanowires. Individual nanowires exhibit well-defined Coulomb blockade oscillations characteristic of charge addition to a single nanostructure with length scales up to at least 400 nm. Further studies demonstrate coherent charge transport through discrete single particle quantum

V. I. Zubov

Using the correlative method of unsymmetrized self-consistent field for strongly anharmonic crystals, the thermodynamic stability and the mechanism its loss is studied for crystals with various types of the chemical bond. The following interaction potentials are utilized: the Lennard-Jones pairwise potential together with Axilrod - Teller three-body one for

Krzysztof Urbanowicz, Janusz A. Holyst

Using a recently developed method of noise level estimation that makes use of properties of the coarse grained-entropy we have analyzed the noise level for the Dow Jones index and a few stocks from the New York Stock Exchange. We have found that the noise level ranges from 40 to 80 percent of the signal variance. The condition of a minimal noise level has be

J. Q. Li, H. X. Yang, R. J. Xiao, Y. G. Shi

Electron energy loss (EEL) spectra have been obtained on materials with the nominal compositions of Na0.33CoO2_yH2O (y = 0, 0.6 and 1.3). Spectral analyses revealed systematic changes in the low-loss energy region (< 10eV) and the core losses(O-K, Co-L3,2) along with the water intercalation. The inter (intra)-band transitions and the relevant plasmon resonan

H. Hong

We investigate the effects of quenched disorder on the coherent response in a driven system of coupled oscillators. In particular, the interplay between quenched noise and periodic driving is explored, with particular attention to the possibility of resonance. The phase velocity is examined as the response of the system; revealed is the enhancement of the fr

Carlos Escudero

The problem of velocity selection of reaction-diffusion fronts has been widely investigated. While the mean field limit results are well known theoretically, there is a lack of analytic progress in those cases in which fluctuations are to be taken into account. Here, we construct an analytic theory connecting the first principles of the reaction-diffusion pr

Jens Dreger, Axel Pelster, Bodo Hamprecht

We develop a recursive method for perturbative solutions of the Fokker-Planck equation with nonlinear drift. The series expansion of the time-dependent probability density in terms of powers of the coupling constant is obtained by solving a set of first-order linear ordinary differential equations. Resumming the series in the spirit of variational perturbati

J. G. Dash, J. S. Wettlaufer

The observation of reduced rotational inertia in a cell containing solid helium 4 has been interpreted as evidence for superfluidity of the solid. An alternative explanation is slippage of the solid at the container wall due to grain boundary premelting between the solid and dense adsorbed layers at the container wall. We calculate the range of film thicknes

L. Benatov, J. S. Wettlaufer

The effect of impurities on the grain boundary melting of ice is investigated through an extension of Derjaguin-Landau-Verwey-Overbeek theory, in which we include retarded potential effects in a calculation of the full frequency dependent van der Waals and Coulombic interactions within a grain boundary. At high dopant concentrations the classical solutal eff

A. E. Koshelev, A. A. Varlamov, V. M. Vinokur

A theory of fluctuations in two-band superconductor MgB$_{2}$ is developed. Since the standard Ginzburg-Landau (GL) approach fails in description of its properties, we generalize it basing on the microscopic theory of a two-band superconductor. Calculating the microscopic fluctuation propagator, we build up the nonlocal two-band GL functional and the corresp

Eric Brunet, Daniel ben-Avraham

The close similarity between the hierarchies of multiple-point correlation functions for the diffusion-limited coalescence and annihilation processes has caused some recent confusion, raising doubts as to whether such hierarchies uniquely determine an infinite particle system. We elucidate the precise relations between the two processes, arriving at the conc

Ya. V. Fominov, A. A. Golubov

We consider the effect of the finite size in the ab-plane on the surface density of states (DoS) in clean d-wave superconductors. In the bulk, the DoS is gapless along the nodal directions, while the presence of a surface leads to formation of another type of the low-energy states, the midgap states with zero energy. We demonstrate that finiteness of the sup

J. C. B. Papaloizou

We study and review disk protoplanet interactions using local shearing box simulations. These suffer the disadvantage of having potential artefacts arising from periodic boundary conditions but the advantage, when compared to global simulations, of being able to capture much of the dynamics close to the protoplanet at high resolution for low computational co

M. H. Siegel, S. R. Majewski, C. Gallart, S. Sohn

We report the results of a photometric search for giant stars associated with the cores of four high velocity clouds (HVCs) -- two of which are compact HVCs -- using the Las Campanas Du Pont 2.5 meter and Cerro Tololo Blanco 4 meter telescopes in combination with a system of filters (Washington M, T_2 + DDO51) useful for identifying low surface gravity, evol

S. Vaughan

We demonstrate a simple method for testing the significance of peaks in the periodogram of red noise data. The procedure was designed to test for spurious periodicities in X-ray light curves of active galaxies, but can be used quite generally to test for periodic components against a background noise spectrum assumed to have a power law shape. The method pro

M. B. Nechaeva, V. G. Gavrilenko, Y. N. Gorshenkov, . B. N. Lipatov

This work devotes to investigations of solar corona and solar wind plasma by the method of radio probing with using of very long baseline interferometry (VLBI). We performed the theoretical calculation of power spectrum of interferometric response to radio source emission, passed through the turbulent medium. Data of theoretical analysis are compared with re

S. Vaughan, A. C. Fabian, K. Iwasawa

The rapid and seemingly random fluctuations in X-ray luminosity of Seyfert galaxies provided early support for the standard model in which Seyferts are powered by a supermassive black hole fed from an accretion disc. However, since EXOSAT there has been little opportunity to advance our understanding of the most rapid X-ray variability. Observations with XMM

I. Molotov, G. Tuccari, M. Nechaeva, N. Dugin

Since 1999 we carried out seven trial VLBI radar experiments under LFVN project. The aim of this work is to adjust new research technique for investigating the Solar system bodies (planets, asteroids, space debris). It is planned to obtain the information on their movement parameters, proper rotation and structure of surface. The transmitter of Evpatoria RT-

W. Schluter, N. Vandenberg

VLBI plays a unique and fundamental role in the maintenance of global reference frames which are required for precise positioning in many research areas related e.g to the understanding and monitoring of global changes, to geodesy, to space missions etc. The International VLBI Service for Geodesy and Astrometry coordinates internationally the VLBI components

T. Pisanu, M. Morsiani, C. Pernechele, F. Buffa

The SRT (Sardinia Radio Telescope) is a general purpose, fully steerable, active surface equipped, 64 meters antenna, which is in an advanced construction state near Cagliari (Sardinia - Italy). It will be an antenna which could improve a lot the performances of the EVN network, particularly at frequencies higher than 22 GHz. The main antenna geometry consis

D. Lapsley, A. Whitney

As broadband access to high speed research and education networks has become increasingly available to radio telescopes around the world the use of e-VLBI has also increased. High bandwidth e-VLBI experiments have been achieved across wide areas (Whitney et al., 2003). e-VLBI has also been used for the transfer of data from &#34;production&#34; experiments.

Y. Murata, H. Hirabayashi, Next Generation Space VLBI Working Group

As presented by Hirabayashi et al. (2004) these proceedings, the VSOP-2 mission is currently being planned. Various kinds of developments are being made for the misson, and here we introduce the large antenna, fast switching scheme using CMG, low noise receivers, gigabit data transmission, and high data rate sampling on-board. We are also studying the system

H. -G. Kim, S. -T. Han, B. W. Sohn, S. -J. Oh

Korea&#39;s new VLBI project to construct the Korean VLBI Network (KVN) started in 2001, as a 7-year project that is fully funded by our government. We plan to build 3 new high-precision radio telescopes of 21-m diameter in 3 places in Korea, which will be exclusively used for VLBI observations. We will install the 2/8, 22 and 43 GHz HEMT receivers within 20

M. Inoue

The VLBI activities in the East Asia region are planning to coordinate among VLBI groups and institutes in China, Japan, and Korea. In these countries, some new projects are going to start or discussed, and some types of collaboration have been already done individually. These new projects are briefly introduced. Under these circumstances, an organization ha

R. G. Strom

The EVN stations encompass elements with a range of diameters, even including an interferometer (the Westerbork Telescope, with up to 14 elements used together as a tied array). In combination, the various station pairs will each produce their own primary beam envelopes, with which the interferometer pattern is modulated. People sometimes forget that in the

A. Szomoru, A. Biggs, M. A. Garrett, H. J. van Langevelde

Spurred by the advent of disk-based recording systems and the nearly explosive increase of internet bandwidth, eVLBI (Parsley et al. 2004) has undergone a remarkable development over the past two years. From ftp-based transfers of small amounts of astronomical data, through near real-time correlation (disk-buffered at the correlator), it has culminated this

R. Dodson, S. Tingay, C. West, C. Phillips

We report on our experiences using the Metsahovi Radio Observatory&#39;s (MRO) VLBI Standard Interface (VSI, Whitney 2002) recorder in a number of astronomical applications. The PC-EVN device is a direct memory access (DMA) interface which allows 512 megabit per second (Mbps) or better recording to &#34;off the shelf&#34; PC components. We have used this set

R. M. Campbell

Recent achievements at the EVN MkIV data processor at JIVE include decreasing the read-out time for the whole correlator to 0.25 seconds (or 0.125 s for half the correlator), improving the end quality of user data (e.g., applying an improved 2-bit van Vleck correction), developing new astronomical capabilities (e.g., oversampling to x 4, wider-field mapping)

I. K. Brown

A series of observations of microquasar GRS1915+105 were made by the MERLIN telescope array in the spring of 2003 at 18 cm. The images show polarization in the jet components, with two epochs displaying Faraday rotation of about 2500 rad/m2. This effect is a demonstration of the similarities between microquasars and extragalactic jets.

Z. Paragi, R. C. Vermeulen, D. C. Homan, J. F. C. Wardle

We present a status report of dedicated circular polarization (CP) global VLBI observations of SS433. The total intensity image of the source is presented. We do not detect linear polarization in the core region of the source. We estimate the errors in D-terms for the EVN, and its effect on the final right-left circular polarization gain calibration. The dat

Mareki Honma

We present the results of multi-epoch VERA observations of W49N - OH43.8-0.1 water maser pair. Based on the dual-beam VLBI observation with VERA, we successfully obtained the phase-referenced maps of OH43.8-0.1 with respect to the W49N reference spot for 3 epochs with a time span of 6 months. The maps were in good agreement with previous studies obtained wit

T. Hirota, VERA project team

We present results of phase-referencing VLBI observations of water maser sources in Orion-Monoceros Molecular Clouds with VERA (VLBI Exploration of Radio Astrometry), which is newly constructed Japanese VLBI network. Main topics of this poster are (1) the aim of one of the first scientific projects for VERA &#34;3-Dimensional Structure and Kinematics of Orio

S. Etoka, R. J. Cohen, M. D. Gray

We present the preliminary results of the first alignment to milliarsecond accuracy of the 6 GHz maser emission in OH and methanol maser lines toward W3(OH). The identifications of Zeeman pairs allowed us to infer the actual velocity of the OH material and the magnetic field strength at the location where 6.7 GHz methanol maser emission arises.

R. Mittal, R. Porcas, O. Wucknitz, A. Biggs

We present the results of phase-referenced VLBA+Effelsberg observations at five frequencies of the gravitational lens B0218+357 to establish the precise registration of the A and B lensed image positions.

A. D. Biggs

Previous VLBI observations of the lens system CLASS B0128+437 showed that the lensed source had a triple sub-component structure. However, one of the images looked very different to the others and it has been suggested that this is due to scatter-broadening in the ISM of the lensing galaxy. We present a new 21-cm EVN map of this system, the low frequency com

A. Pushkarev, I. Molotov, M. Nechaeva, Yu. Gorshenkov

In November 1999 we carried out VLBI observations of several quasars and BL Lacertae objects at 1.66 GHz. Six antennas participated in the experiment (Bear Lakes, Svetloe, Pushchino, Noto, HartRAO, and Seshan). The results for six sources (0420+022, 0420-014, 1308+326, 1345+125, 1803+784, and DA193) are presented and discussed.

T. An, J. -H. Zhao, X. -Y. Hong, Z. -Q. Shen

We present a spectrum of Sgr A* observed simultaneously on June 17, 2003 at wavelengths from 90 to 0.7 cm with the VLA. In the spectrum, we also include the measurements of Sgr A* observed on the same day with the GMRT at 49 cm, the SMA at 0.89 mm and the Keck II at 3.8 $μ$m. The spectrum at the centimeter wavelengths suggests the presence of a break wavelen

S. Kameno, M. Inoue, Z. -Q. Shen, S. Sawada-Satoh

We report results of pentachromatic VLBI survey for 18 GHz-peaked spectrum sources. Spectral fitting at every pixel across five frequencies allows us to illustrate distribution of optical depth in terms of free-free absorption or synchrotron self absorption. Quasars and Seyfert 1 sources show one-sided morphology with a core at the end where the optical dept

M. K. Argo, A. Pedlar, T. W. B. Muxlow, R. J. Beswick

Several new main line OH masers have been detected in the nearby starburst galaxy M82. Eight masers have been detected to 5 sigma, six of which are new detections. Observations covering both the 1665 and 1667 MHz lines with both the Very Large Array (VLA) and the Multi-Element Radio Linked Interferometer Network (MERLIN) have been used to accurately measure

Jonathan E. Grindlay

The high resolution X-ray imaging and broad-band moderate resolution spectra enabled by the ACIS cameras on the Chandra X-ray Observatory have opened a new window in our study of millisecond pulsars (MSPs). Given the large excess of MSPs in globular clusters vs. the field, globular clusters are the favored sites for MSP study. Globular clusters (GCs) offer a

Andrew Gould, Juna A. Kollmeier, Julio Chaname, Samir Salim

We calibrate the photographic photometry of the revised New Luyten Two-Tenths catalog (rNLTT) by matching 3448 rNLTT stars to the Sloan Digital Sky Survey (SDSS). The correction is linear in magnitude and goes from zero at V ~ 14 to 0.32 mag at V=19, in the sense that rNLTT was previously too bright. The correction implies that the underlying USNO-A2.0 photo

Debajyoti Choudhury, Santosh Kumar Rai, Sreerup Raychaudhuri

Sneutrino resonances at a high energy linear e+e- collider may be one of the clearest signals of supersymmetry without R-parity, especially when the R-parity-violating coupling is too small to produce observable excesses in four-fermion processes. However, there is no guarantee that the sneutrino pole will lie anywhere near the machine energy. We show that a

J. Ross, R. P. Thomas

We make a systematic study of the Hilbert-Mumford criterion for different notions of stability for polarised algebraic varieties $(X,L)$; in particular for K- and Chow stability. For each type of stability this leads to a concept of slope $μ$ for varieties and their subschemes; if $(X,L)$ is semistable then $μ(Z)\leμ(X)$ for all $Z\subset X$. We give example

D. Fargion

The present gravitational wave detectors are reaching lowest metric deviation fields able to detect galactic and extra-galactic gravitational waves, related to Supernova explosions up to Virgo cluster. The same gravitational wave detector are nevertheless almost able to reveal, in principle, near field Newtonian gravitational perturbations due to fast huge m

Robert Bluhm, Alan Kostelecky

The fate of the Nambu-Goldstone modes arising from spontaneous Lorentz violation is investigated. Using the vierbein formalism, it is shown that up to 10 Lorentz and diffeomorphism Nambu-Goldstone modes can appear and that they are contained within the 10 modes of the vierbein associated with gauge degrees of freedom in a Lorentz-invariant theory. A general

Robert de Mello Koch, Antal Jevicki, Joao P. Rodrigues

Following the recent work of hep-th/0405076 we discuss the emergence of D-brane instanton solutions in c=0 noncritical string theory. Our emphasis is on finding the D-instanton effects in a field theoretic setting. Using the framework of single matrix collective field theory (CSFT) we exhibit the appearance of such solutions. Some subtle issues regarding the

Maxim Pavlov

We present three different linearizable extensions of the Gurevich-Zybin system. Their general solutions are found by reciprocal transformations. In this paper we rewrite the Gurevich-Zybin system as a Monge-Ampere equation. By application of reciprocal transformation this equation is linearized. Infinitely many local Hamiltonian structures, local Lagrangian

Lotfi Zekri

We analyze a random resistor-inductor-capacitor $(RLC)$ lattice model of 2-dimensional metal-insulator composites. The results are compared with Bruggeman&#39;s and Landauer&#39;s Effective Medium Approximations where a discrepancy was observed for some frequency zones. Such a discrepancy is mainly caused by the strong conductivity fluctuations. Indeed, a tw

Zhang Hongsheng, Guo Zongkuan

We investigate all the brane instanton solutions--an Einstein brane inhabiting at different positions in 5-dimensional negative curvature Einstein bulk. We construct a brane instanton model consisting of a brane with asymmetric bulk along two sides of the brane. And the junction condition of the resulting space-time is analyzed in the frame of induced gravit

M. V. Bondarko

This paper is a summary of author&#39;s results on finite flat commutative group schemes. The properties of the generic fibre functor are discussed. A complete classification of finite local flat commutative group schemes over mixed characteristic complete discrete valuation rings in terms of their Cartier modules (defined by Oort) is given. We also state se

Junji Hisano, Shigeki. Matsumoto, Mihoko M. Nojiri, Osamu Saito

Detection of gamma rays from dark matter annihilation in the galactic center is one of the feasible techniques to search for dark matter. We evaluate the gamma ray flux in the case that the dark matter has an electroweak SU(2)_L charge. Such dark matter is realized in the minimal supersymmetric standard model (MSSM) when the lightest SUSY particle is the Hig

P. Tzanavaris, J. K. Webb, M. T. Murphy, V. V. Flambaum

Quasar absorption spectra at 21-cm and UV rest-wavelengths are used to estimate the time variation of x=alpha^2 g_p mu, where alpha is the fine structure constant, g_p the proton g factor, and m_e/m_p=mu the electron/proton mass ratio. Over a redshift range 0.24 ~< z_abs ~< 2.04, <Delta x/x>_total_weighted=(1.17+-1.01) x 10^-5. A linear fit gives d/dt{x}/x=(

Munshi G. Mustafa

Considering the collisional energy loss rates of heavy quarks from hard light parton interactions the total energy loss of a charm quark for a static medium has been computed. For the energy range $E\sim (5-10)$ GeV of charm quark, it is found to be almost same order as that of radiative ones estimated to a first order opacity expansion. The collisional ener