April 2003 arXiv papers — page 8

Gregory Lawler

This paper describes joint work with Oded Schramm and Wendelin Werner establishing the values of the planar Brownian intersection exponents from which one derives the Hausdorff dimension of certain exceptional sets of planar Brownian motion. In particular, we proof a conjecture of Mandelbrot that the dimension of the frontier is 4/3. The proof uses a univers

Kurt Johansson

We summarize some of the recent developments which link certain problems in combinatorial theory related to random growth to random matrix theory.

Mu-Fa Chen

This paper consists of four parts. In the first part, we explain what eigenvalues we are interested in and show the difficulties of the study on the first (non-trivial) eigenvalue through examples. In the second part, we present some (dual) variational formulas and explicit bounds for the first eigenvalue of Laplacian on Riemannian manifolds or Jacobi matric

Erwin Bolthausen

We consider d-dimensional random surface models which for d=1 are the standard (tied-down) random walks (considered as a random ``string''). In higher dimensions, the one-dimensional (discrete) time parameter of the random walk is replaced by the d-dimensional lattice \Z^d, or a finite subset of it. The random surface is represented by real-valued ra

Jean Bertoin

We present some aspects of the so-called additive coalescence, with a focus on its connections with random trees, Brownian excursion, certain bridges with exchangeable increments, Lévy processes, and sticky particle systems.

Gérard Ben-Arous

We survey the recent mathematical results about aging in certain simple disordered models. We start by the Bouchaud trap model. We then survey the results obtained for simple models of spin-glass dynamics, like the REM (the Random Energy Model, which is well approximated by the Bouchaud model on the complete graph), then the spherical Sherrington-Kirkpatrick

Yuqing Chen, Henry Glover, Craig Jensen

If $G$ is a free product of finite groups, let $ΣAut_1(G)$ denote all (necessarily symmetric) automorphisms of $G$ that do not permute factors in the free product. We show that a McCullough-Miller [D. McCullough and A. Miller, {\em Symmetric Automorphisms of Free Products}, Mem. Amer. Math. Soc. 122 (1996), no. 582] and Gutiérrez-Krstić [M. Gutiérrez and S.

Joaquim Gomis, Toni Mateos, Pedro J. Silva, Antoine Van Proeyen

We show that the supertube configurations exist in all supersymmetric type IIA backgrounds which are purely geometrical and which have, at least, one flat direction. In other words, they exist in any spacetime of the form R^{1,1} x M_8, with M_8 any of the usual reduced holonomy manifolds. These generalised supertubes preserve 1/4 of the supersymmetries pres

Aalok Misra

We study the gauged sigma model and its mirror Landau-Ginsburg model corresponding to type IIA on the Fermat degree-24 hypersurface in WCP^4[1,1,2,8,12] (whose blow-up gives the smooth CY_3(3,243)) away from the orbifold singularities, and its orientifold by a freely-acting antiholomorphic involution. We derive the Picard-Fuchs equation obeyed by the period

Nemani V. Suryanarayana

We describe a supersymmetric example of the holographic duality between 3 dimensional vector models and higher spin gauge theories in AdS_4, first proposed in a bosonic context by Klebanov and Polyakov. We argue that a particular Fradkin-Vasiliev type supersymmetric higher spin gauge theory in AdS_4 with 16 supersymmetries is dual to the singlet sector of bi

Takeshi Oota

In the framework of the quantum inverse scattering method, we consider a problem of constructing local operators for two-dimensional quantum integrable models, especially for the lattice versions of the nonlinear Schrodinger and sine-Gordon models. We show that a certain class of local operators can be constructed from the matrix elements of the monodromy ma

Khaled Saaidi, Mohammad Khorrami

The large-group behavior of the nonlocal YM$_2$'s and gYM$_2$'s on a cylinder or a disk is investigated. It is shown that this behavior is similar to that of the corresponding local theory, but with the area of the cylinder replaced by an effective area depending on the dominant representation. The critical areas for nonlocal YM$_2$'s on a cylind

Soonkeon Nam, Heeyong Park, Yunseok Seo

Quantum mechanical fluctuations in an interval give rise to the Casimir effect, which destabilizes the size of the interval. This can be problematic in constructing Kaluza-Klein theories. We consider the possibility that a breakdown of the Poincar\'e symmetry in an extra dimension can solve this instability problem. As a specific example, we consider the spa

A. Smida, M. Hachemane, A. H. Hamici, R. Djelid

A (M4 x M4) x Z4 model, describing an extended particle composed of two local modes and represented by a field psi(x, xi ;z), is formulated in its most general form (x, xi ; z) belong to (M4 x M4) x Z4. The 'z' argument specifies whether the particle is observable, unobservable, or partially observable (the latter case appears in two forms). In this

B. Grzadkowski, J. F. Gunion

Generalizations of the Randall-Sundrum model containing a bulk scalar field $Φ$ interacting with the curvature $R$ through the general coupling $R f(Φ)$ are considered. We derive the general form of the effective 4D potential for the spin-zero fields and show that in the mass matrix the radion mixes with the Kaluza-Klein modes of the bulk scalar fluctuations

Michael Gronau

While the Kobayashi--Maskawa model of CP violation passed its first crucial precision test in $B\to J/ψK_S$, other CP asymmetries in $B$ and $B_s$ decays will have to be measured in order to critically test and overconstrain the model in an unambiguous way. On another front, the chirality of weak $b$-quark couplings has not yet been carefully tested. We disc

Hiroyuki Hagura

We propose a hybrid model of simplicial quantum gravity by performing at once dynamical triangulations and Regge calculus. A motive for the hybridization is to give a dynamical description of topology-changing processes of Euclidean spacetime. In addition, lattice diffeomorphisms as invariance of the simplicial geometry are generated by certain elementary mo

Y. Unno, K. Suzuki

We report an improved measurement of the partial-rate CP asymmetry in B+ => K0pi+ and B- => K0bar pi- decays. The analysis is based on a data sample of 85 million BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e+ e- storage ring. We measure Acp(K0pi+-) = 0.07^{+0.09 +0.01}_{-0.08 -0.03}, where the first and second erro

M. Ripani, V. D. Burkert, V. Mokeev, M. Battaglieri

The cross section for the reaction $ e p \to e^{\prime} p π^{+} π^{-}$ was measured in the resonance region for 1.4$<$W$<$2.1 GeV and 0.5$<Q^{2}<$1.5 GeV$^{2}$/c$^{2}$ using the CLAS detector at Jefferson Laboratory. The data show resonant structures not visible in previous experiments. The comparison of our data to a phenomenological prediction using availa

U. Husemann, M. Adams, M. Bocker, M. Bruggemann

We present the design and commissioning of a new multiplicity veto for the HERA-B detector, a fixed-target spectrometer originally designed to study the physics of B mesons in proton-nucleus interactions. The HERA-B trigger is a message-driven multi-level track trigger. The first level trigger (FLT) consists of custom-made electronics, and the higher trigger

G. Mavromanolakis

We present a signal-from-background separation study based on neural networks technique applied to a W/quartz fiber calorimeter. Performance results in terms of signal efficiency and improvement of the signal-to-background ratio are presented. We conclude that by using neural networks we can efficiently separate signal from background and achieve a signal en

S. Deser

We consider Bel-Robinson-like higher derivative conserved two-index tensors $H_\mn$ in simple matter models, following a recently suggested Maxwell field version. In flat space, we show that they are essentially equivalent to the true stress-tensors. In curved Ricci-flat backgrounds it is possible to redefine $H_\mn$ so as to overcome non-commutativity of co

G. Zocchi, A. Omerzu, T. Kuriabova, J. Rudnick

We have measured the temperature driven denaturing, or melting transition in poly d(A)-poly d(T) DNA oligomers of various lengths in different buffer conditions. Our findings are in clear disagreement with two state, reaction kinetics model, and we find that the so-called zipper model, where denaturing proceeds through opening of the duplex at the ends descr

D. D. Shivagan, P. M. Shirage, L. A. Ekal, S. H. Pawar

In the present investigation, the novel two-step electrochemical process of room temperature synthesis of Hg-1212 superconducting films has been developed and reported first time. Electrochemical parameters were optimized by studying cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) for the deposition of Hg-Ba-Ca-Cu alloy at

Cz. Oleksy

The lattice gas model for adsorption of alkaline elements on W(112) surface is studied by Monte Carlo simulations. The model includes dipole--dipole interaction as well as long-range indirect interaction. The numerical results show that truncation of the indirect interaction even at 200$Å$ may change a phase diagram, i.e., new phases containing domain walls

Ph. Blanchard, A. Ruschhaupt, T. Krueger

We study graphs obtained by successive creation and destruction of edges into small neighborhoods of the vertices. Starting with a circle graph of large diameter we obtain small world graphs with logarithmic diameter, high clustering coefficients and a fat tail distribution for the degree. Only local edge formation processes are involved and no preferential

A. Wacker, S. -C. Lee, M. F. Pereira

Quantum cascade lasers can be modeled within a hierarchy of different approaches: Standard rate equations for the electron densities in the levels, semiclassical Boltzmann equation for the microscopic distribution functions, and quantum kinetics including the coherent evolution between the states. Here we present a quantum transport approach based on nonequi

V. N. Bogomolov

There exists a class of non-stoichiometric materials (berthollides) that can be considered as constituted by two sublattices, which have specific physicochemical properties. These properties can be essentially modified by even rather weak interaction between these components. One of them can be regarded as a rigid matrix, while another one as a filling in th

J. G. Rodrigo, H. Suderow, S. Vieira

We report on the study of superconducting nanotips and nanobridges of lead with a Scanning Tunnelling Microscope in tunnel and point contact regimes. We deal with three different structures. A nanotip that remains superconducting under a field of 2 T. For this case we present model calculations of the order parameter, which are in good agreement with the exp

Marcin Mierzejewski, Maciej M. Maska

We analyze the role of Zeeman and orbital pair breaking mechanisms in models appropriate for short coherence length superconductors. In particular, we investigate the attractive Hubbard and the pair hoping models. The orbital pair breaking mechanism dominates in the majority of models with $s$--wave and $d$--wave superconducting order parameters. On the othe

A. Braunstein, R. Mulet, A. Pagnani, M. Weigt

We study the graph coloring problem over random graphs of finite average connectivity $c$. Given a number $q$ of available colors, we find that graphs with low connectivity admit almost always a proper coloring whereas graphs with high connectivity are uncolorable. Depending on $q$, we find the precise value of the critical average connectivity $c_q$. Moreov

H. Takayama

We study numerically temperature-shift and field-shift aging protocols on the 3-dimensional (3D) Ising Edwards-Anderson (EA) spin-glass (SG) model focusing on respectively the temperature-chaos nature and the stability under a static field of the SG phase. The results of the latter strongly support the droplet theory which predicts the instability of the SG

M. -Carmen Miguel, Jose S. Andrade, Stefano Zapperi

A wide variety of interacting particle assemblies driven by an external force are characterized by a transition between a blocked and a moving phase. The origin of this deblocking transition can be traced back to the presence of either external quenched disorder, or of internal constraints. The first case belongs to the realm of the depinning transition, whi

R. Eder, Y. Ohta

The hole-doped 2D t-J model is studied by exact diagonalization on a 5 x 4 cluster which, unlike the standard tilted square clusters, can in principle accomodate an antiphase domain wall. For hole concentration 10% and J/t >= 0.5 the ground state energy/site is lower than the conventional tilted square 20-site-cluster. In the ground state two holes form a lo

D. Bolle, J. Busquets Blanco, G. M. Shim, T. Verbeiren

The parallel dynamics of the fully connected Blume-Emery-Griffiths neural network model is studied for arbitrary temperature. By employing a probabilistic signal-to-noise approach, a recursive scheme is found determining the time evolution of the distribution of the local fields and, hence, the evolution of the order parameters. A comparison of this approach

I. Felner, E. Galstyan

We have investigated the MoSr2R1.5Ce0.5Cu2O10-d (Mo-1222R, R=rare earth) system by several complementary experimental techniques. In contrast to the iso-structural RuSr2R1.5Ce0.5Cu2O10-d (Ru-1222) system, in which superconductivity (SC) in the CuO2 planes and weak-ferromagnetism in the Ru sub-lattice coexists, in Mo-1222, displays a competition between the t

Yukitoshi Motome, Nobuo Furukawa

Curie temperature and exponents are studied for the three-dimensional double-exchange model. Applying the O(N) Monte Carlo algorithm, we perform systematic finite-size scaling analyses on the data up to $20^3$ sites. The obtained values of the critical exponents are consistent with those of the Heisenberg universality class, and clearly distinct from the mea

Gerrit E. W. Bauer, Arne Brataas, Yaroslav Tserkovnyak, Bart J. van Wees

A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure-drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin-valve. The device can operate at room temperature, but in o

Nicolas Vernier, Dan A. Allwood, Del Atkinson, Michael D. Cooke

We demonstrate movement of a head-to-head domain wall through a magnetic nanowire simply by passing an electrical current through the domain wall and without any external magnetic field applied. The effect depends on the sense and magnitude of the electrical current and allows direct propagation of domain walls through complex nanowire shapes, contrary to th

J. Brand, I. Haering, J. -M. Rost

A relation between the number of bound collective excitations of an atomic Bose-Einstein condensate and the phase shift of elastically scattered atoms is derived. Within the Bogoliubov model of a weakly interacting Bose gas this relation is exact and generalises Levinson&#39;s theorem. Specific features of the Bogoliubov model such as complex-energy and cont

Yukitoshi Motome, Nobuo Furukawa, Naoto Nagaosa

Double-exchange model interacting with adiabatic phonons is studied in the presence of randomness by using the Monte-Carlo method and the systematic size-scaling analysis. A bicritical behavior is found between the ferromagnetic metal and the charge-ordered insulator. We find the distinct response to the randomness between these two states, which agrees well

H. G. Katzgraber, F. Pazmandi, C. R. Pike, Kai Liu

We report results demonstrating a singularity in the hysteresis of magnetic materials, the reversal-field memory effect. This effect creates a nonanalyticity in the magnetization curves at a particular point related to the history of the sample. The microscopic origin of the effect is associated with a local spin-reversal symmetry of the underlying Hamiltoni

Helmut G. Katzgraber

We report results from Monte Carlo simulations of the two- and three-dimensional gauge glass at low temperature using parallel tempering Monte Carlo. In two dimensions, we find strong evidence for a zero-temperature transition. By means of finite-size scaling, we determine the stiffness exponent theta = -0.39 +/- 0.03. In three dimensions, where a finite-tem

Carlos R. Fadragas, Manuel Rodriguez, Rolando Bonal

The estimation of mechanical properties of concrete is one of the most important applications of the ultrasonic method. This technique often involves the measuring of the ultrasonic pulse propagation velocity. However, there exist some factors influencing the effective ultrasonic pulse propagation velocity in concrete. This paper is devoted to a discussion o

Masanori Ichioka, Noriyuki Nakai, Kazushige Machida

Superconducting double transition in PrOs_4_Sb_12 is investigated by analyzing the anisotropy of the upper critical field H_c2 in the ab-plane, and the possible pairing state is discussed. When mixing due to gradient coupling is active, the twofold-symmetric component is necessarily induced in the fourfold symmetric phase, leading to the twofold oscillation

Bogdan A. Bernevig, Zaira Nazario, David I. Santiago

We show that an array of Josephson coupled Cooper paired planes can never have long range phase coherence at any finite temperature due to an infrared divergence of phase fluctuations. The phase correlations decay in a slow enough manner providing enough local phase coherence as to make possible the nucleation of vortices. The planes then acquire Kosterlitz-

K. K. Lee

An understanding of high temperature superconductivity clearly requires the nature of its normal state, however the normal state of the cuprates is poorly understood. One possible explanation is the bipolaronic model where mobile, heavily phonon-dressed holes (polarons) are paired in real space. The ground state is made up of intersite singlet bipolarons whe

Y. Tsue, D. Vautherin, T. Matsui

Variational method is applied to describe Bose-Einstein condensates (BEC) interacting via a pseudo-potential, taking into account quantum fluctuations around the mean field by the Gaussian approximation. Contributions from the pair-wise scattering by the singular potential should be removed carefully to avoid double countings in the perturbation series in te

Farhad H Jafarpour

We study a phase transition in a non-equilibrium model first introduced in [5], using the Yang-Lee description of equilibrium phase transitions in terms of both canonical and grand canonical partition function zeros. The model consists of two different classes of particles hopping in opposite directions on a ring. On the complex plane of the diffusion rate w

Qiuping A. Wang

The incomplete statistics for complex systems is characterized by a so called incompleteness parameter $ω$ which equals unity when information is completely accessible to our treatment. This paper is devoted to the discussion of the incompleteness of accessible information and of the physical signification of $ω$ on the basis of fractal phase space. $ω$ is s

D. D. Kocevski, H. Ebeling, C. R. Mullis

The Clusters in the Zone of Avoidance (CIZA) project is producing the first statistically complete catalogue of X-ray selected galaxy clusters behind the Galactic plane. Current optically selected cluster catalogues have excluded a wide band of sky centered on the Milky Way (|b| < 20 deg) due to the high extinction and stellar obscuration at low Galactic lat

Joern Rossa, Ralf-Juergen Dettmar

In a series of two papers we present results of a new H-alpha imaging survey, aiming at the detection of extraplanar diffuse ionized gas in halos of late-type spiral galaxies. We have investigated a sample of 74 nearby edge-on spirals, covering the northern and southern hemisphere. In 30 galaxies we detected extraplanar diffuse emission at mean distances of

Taku Takeuchi, D. N. C. Lin

We study the outflow of dust particles on the surface layers of optically thick disks. At the surface of disks around young stars, small dust particles (size < 10 micron) experience stellar radiation pressure support and orbit more slowly than the surrounding gas. The resulting tail-wind imparts energy and angular momentum to the dust particles, moving them

S. C. Ellis, L. R. Jones

K band observations of the galaxy populations of three high redshift (z=0.8-1.0), X-ray selected, massive clusters are presented. The observations reach a depth of K = 21.5, corresponding to K*+3.5 mag. The evolution of the galaxy properties are discussed in terms of their K band luminosity functions and the K band Hubble diagram of brightest cluster galaxie

Jason Pruet

We discuss the neutrino signature of a relativistic jet propagating through a stellar envelope, a scenario realized in the collapsar model for Gamma Ray Bursts (GRBs). It is shown that the dramatic slowing of the jet deep within the star is accompanied by inelastic neutron-nucleon collisions and the conversion of a substantial fraction of the jet kinetic ene

G. Mark Voit, Michael L. Balogh, Richard G. Bower, Cedric G. Lacey

The entropy distribution of the intracluster medium and the shape of its confining potential well completely determine the X-ray properties of a relaxed cluster of galaxies, motivating us to explore the origin of intracluster entropy and to describe how it develops in terms of some simple models. We present an analytical model for smooth accretion, including

Arunav Kundu, Thomas J. Maccarone, Stephen E. Zepf, Thomas H. Puzia

We have studied the low mass X-ray binary (LMXB) populations within and outside globular clusters (GC) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate age cluster population of NGC 4365, as has be

Sergio Colafrancesco, Arnon Dar, Alvaro De Rujula

The radiative cooling time of the X-ray-emitting plasma near the center in many clusters of galaxies is shorter than the age of the cluster, but neither the expected large drop in central temperature --nor the expected mass flow towards the pressure-depleted cluster centers-- are observed. We propose a solution to these ``cooling flow&#39;&#39; problems wher

M. J. Hardcastle, D. M. Worrall, R. P. Kraft, W. R. Forman

We present new, high dynamic range VLA images of the inner jet of the closest radio galaxy, Centaurus A. Over a ten-year baseline we detect apparent sub-luminal motions (v ~ 0.5c) in the jet on scales of hundreds of pc. The inferred speeds are larger than those previously determined using VLBI on smaller scales, and provide new constraints on the angle made

Carl H. Gibson

A quantum gravitational instability is identified at Planck scales between non-spinning extreme Schwarzschild black holes and spinning extreme Kerr black holes, which produces a turbulent Planck particle gas. Planck inertial vortex forces balance gravitational forces as the Planck turbulence cascades to larger scales and the universe expands and cools. Turbu

H. M. Schmid, I. Appenzeller, U. Burch

We report the detection of high linear polarization in the bright Seyfert 1 galaxy ESO 323-G077. Based on optical spectropolarimetry with FORS1 at the VLT we find a continuum polarization which ranges from 2.2 % at 8300A to 7.5 % at 3600A. Similar amounts of linear polarization are found for the broad emission lines, while the narrow lines are not polarized.

Konrad Kuijken

The basic equations and geometry of gravitational lensing are described, as well as the most important contexts in which it is observed in astronomy: strong lensing, weak lensing and microlensing.

C. P. Dullemond, A. Natta

The two-layer disk models of Chiang & Goldreich (1997, henceforth CG) and its derivatives are popular among astronomers because of their simplicity and the clear predictions they make for the SEDs of T Tauri stars and Herbig Ae/Be stars. Moreover, they can be computed quickly, which is a great advantage when fitting observations using automated procedures. I

A. C. Gonzalez-Garcia, T. S. van Albada

We have carried out computer simulations to study the effect of merging on the fundamental plane (FP) relation. Initially, systems are spherical Jaffe models following a simple scaling relation (M/R_e^2 = constant). They have been put on the FP by imposing different M/L values. Various orbital characteristics have been considered. Our results show that the m

O. Wucknitz, L. Wisotzki, S. Lopez, M. D. Gregg

We present the first separate spectra of both components of the small-separation double QSO HE0512-3329 obtained with HST/STIS in the optical and near UV. The similarities especially of the emission line profiles and redshifts strongly suggest that this system really consists of two lensed images of one and the same source. The emission line flux ratios are

Soeren S. Larsen, Jean P. Brodie

Several recent studies have reported a mean size difference of about 20% between the metal-rich and metal-poor subpopulations of globular clusters (GCs) in a variety of galaxies. In this paper we investigate the possibility that the size difference might be a projection effect, resulting from a correlation between cluster size and galactocentric distance, co

R. Tylenda, N. Siodmiak, S. K. Gorny, R. L. M. Corradi

We have measured angular dimensions of 312 planetary nebulae from their images obtained in Halpha (or Halpha + [NII]). We have applied three methods of measurements: direct measurements at the 10% level of the peak surface brightness, Gaussian deconvolution and second-moment deconvolution. The results from the three methods are compared and analysed. We prop

Witold Maciejewski

Bars in galaxies are mainly supported by particles trapped around closed periodic orbits. These orbits respond to the bar&#39;s forcing frequency only and lack free oscillations. We show that a similar situation takes place in double bars: particles get trapped around orbits which only respond to the forcing from the two bars and lack free oscillations. We f

Cuihua Du, Xu Zhou, Jun Ma, Alfred B-C Chen

We report the first results of star counts carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000 Å in the BATC survey. We analyze a sample of over 1400 main sequence stars ($14\le$V$\le21$), which lie in the field with central coordinates R.A.=$09^h53^m13^s.30$ and DEC=47

Iver H. Cairns, P. Das, P. A. Robinson, S. Johnston

The variability of the Vela pulsar (PSR B0833-45) corresponds to well-defined field statistics that vary with pulsar phase, ranging from Gaussian intensity statistics off-pulse to approximately power-law statistics in a transition region and then lognormal statistics on-pulse, excluding giant micropulses. These data are analyzed here in terms of two superpos

Iver H. Cairns, S. Johnston, P. Das

Individual pulses from pulsars have intensity-phase profiles that differ widely from pulse to pulse, from the average profile, and from phase to phase within a pulse. Widely accepted explanations do not exist for this variability or for the mechanism producing the radiation. The variability corresponds to the field statistics, particularly the distribution o

Mitsuru Honda, Yasuko. S. Honda

We propose a novel mathematical method to construct an exact polytropic sphere in self-gravitating hydrostatic equilibrium, improving the non-linear Poisson equation. The central boundary condition for the present equation requires a ratio of gas pressure to total one at the centre, which is uniquely identified by the whole mass and molecular weight of the s

Nils Bergvall, Eija Laurikainen, Susanne Aalto

We report on a study of tidally triggered star formation in galaxies, based on spectroscopic/photometric observations in the optical/near-IR of a magnitude limited sample of 59 systems of interacting and merging galaxies and a comparison sample of 38 normal isolated galaxies. In contrast to results from previous investigations, our global UBV colours do not

B. Lorenz, J. Cmaidalka, R. L. Meng, C. W. Chu

The effect of hydrostatic pressure on the superconducting transition temperature of Na{0.35}CoO{2}.yH{2}O was investigated by ac susceptibility measurements up to 1.6 GPa. The pressure coefficient of T{c} is negative and the dependence T{c}(p) is nonlinear over the pressure range investigated. The magnitude of the average dlnT{c}/dp=-0.07 GPa^{-1} is compara

Marilia J. Sartori, Jacques R. D. Lepine, Wilton S. Dias

We investigate the spatial distribution, the space velocities and age distribution of the pre-main sequence (PMS) stars belonging to Ophiuchus, Lupus and Chamaeleon star-forming regions (SFRs), and of the young early-type star members of the Scorpius-Centaurus OB association. These young stellar associations extend over the galactic longitude range from 280

S. K. Swain, T. E. Browder

We report results on the decay $B^{-} \to D_{CP}K^{-}$ and its charge conjugate using a data sample of 85.4 million $B\bar{B}$ pairs recorded at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric $e^{+}e^{-}$ storage ring. Ratios of branching fractions of Cabibbo-suppressed to Cabibbo-favored processes are determined to be ${\cal B}(B^- \to

Yogesh N. Joglekar, A. H. Castro Neto, Alexander V. Balatsky

Recently, we discovered a mistake in our Letter on phase dynamics in granular d-wave superconductors, which we corrected in an Erratum published last week. This is an expanded version of the Erratum, containing details and supporting numerical results.

G. M. Bruun, C. J. Pethick

For calculating low-energy properties of a dilute gas of atoms interacting via a Feshbach resonance, we develop an effective theory in which the parameters that enter are an atom-molecule coupling strength and the magnetic moment of the molecular resonance. We demonstrate that for resonances in the fermionic systems $^{6}$Li and $^{40}$K that are under exper

Philip R. Page, Simon Capstick

We show that current analyses of experimental data indicate that the strong decay mode pi_2 -> b_1 pi is anomalously small. Non-relativistic quark models with spin-1 quark pair creation, such as ^3P_0, ^3S_1 and ^3D_1 models, as well as instanton and lowest order one-boson (in this case pi) emission models, can accommodate the analyses of experimental data,

Kristen Menou

The local axisymmetric stability of hydrodynamical and magnetized, nearly-Keplerian gaseous accretion disks around non-rotating black holes is examined in the vicinity of the classical marginally-stable orbit (at radii ~ R_ms). An approximate Paczynski-Wiita pseudo-Newtonian potential is used. Hydrodynamical disks are linearly unstable inside a radius which

Alexandre Refregier, Richard Massey, Jason Rhodes, Richard Ellis

Weak gravitational lensing provides a unique method to directly map the dark matter in the universe and measure cosmological parameters. Current weak lensing surveys are limited by the atmospheric seeing from the ground and by the small field of view of existing space telescopes. We study how a future wide-field space telescope can measure the lensing power

Richard Massey, Jason Rhodes, Alexandre Refregier, Justin Albert

We study the accuracy with which weak lensing measurements could be made from a future space-based survey, predicting the subsequent precisions of 3-dimensional dark matter maps, projected 2-dimensional dark matter maps, and mass-selected cluster catalogues. As a baseline, we use the instrumental specifications of the Supernova/Acceleration Probe (SNAP) sate

Jason Rhodes, Alexandre Refregier, Richard Massey, the SNAP Collaboration

A wide field space-based imaging telescope is necessary to fully exploit the technique of observing dark matter via weak gravitational lensing. This first paper in a three part series outlines the survey strategies and relevant instrumental parameters for such a mission. As a concrete example of hardware design, we consider the proposed Supernova/Acceleratio

Davide Gaiotto, Nissan Itzhaki, Leonardo Rastelli

Sen has recently drawn attention to an exact time-dependent Boundary Conformal Field Theory with the space-time interpretation of brane creation and annihilation. An interesting limit of this BCFT is formally equivalent to an array of D-branes located in imaginary time. This raises the question: what is the meaning of D-branes in imaginary time? The answer w

D. London, N. Sinha, R. Sinha

We show that an angular analysis of B --> V1 V2 decays yields numerous tests for new physics in the decay amplitudes. Unlike direct CP asymmetries, many of these new-physics observables are nonzero even if the strong phase differences vanish. For certain observables, neither time-dependent measurements nor tagging is necessary. Should a signal for new physic

Federico Piazza, Christian Marinoni

We propose a phenomenological model where the gravitational interaction between dark matter and baryons is suppressed on small, subgalactic scales. We describe the gravitational force by adding a Yukawa contribution to the standard Newtonian potential and show that this interaction scheme is effectively suggested by the available observations of the inner ro

Kaustubh Agashe, Christopher D. Carone

We consider the flavor structure of supersymmetric theories that can account for the deviation of the observed time-dependent CP asymmetry in B --> phi K_S from the standard model prediction. Assuming simple flavor symmetries and effective field theory, we investigate possible correlations between sizable supersymmetric contributions to b --> s transitions a

Gerald A. Miller

A model proton wave function, constructed using Poincare invariance, and constrained by recent electromagnetic form factor data, is used to study the shape of the proton. Spin-dependent quark densities are defined as matrix elements of density operators in proton states of definite spin-polarization, and shown to have an infinite variety of non-spherical sha

M. B. Hastings

We use scaling results to identify the crossover to mean-field behavior of equilibrium statistical mechanics models on a variant of the small world network. The results are generalizable to a wide-range of equilibrium systems. Anomalous scaling is found in the width of the mean-field region, as well as in the mean-field amplitudes. Finally, we consider non-e

K. L. Luhman, John R. Stauffer, A. A. Muench, G. H. Rieke

We present a new census of the stellar and substellar members of the young cluster IC 348. We have obtained images at I and Z for a 42&#39;x28&#39; field encompassing the cluster and have combined these measurements with previous optical and near-infrared photometry. From spectroscopy of candidate cluster members appearing in these data, we have identified 1

I. A. Dmitriev, A. D. Mirlin, D. G. Polyakov

The frequency-dependent conductivity $σ_{xx}(ω)$ of 2D electrons subjected to a transverse magnetic field and smooth disorder is calculated. The interplay of Landau quantization and disorder scattering gives rise to an oscillatory structure that survives in the high-temperature limit. The relation to recent experiments on photoconductivity by Zudov {\it et a

Thomas Hertog, Gary T. Horowitz, Kengo Maeda

We show that a large class of supersymmetric compactifications, including all simply connected Calabi-Yau and G_2 manifolds, have classical configurations with negative energy density as seen from four dimensions. In fact, the energy density can be arbitrarily negative -- it is unbounded from below. Nevertheless, positive energy theorems show that the total

Michael C. Birse, Chung-Wen Kao, Gouranga C. Nayak

We use a transport-theory approach to construct the static propagator of a gauge boson in a plasma with a general axially- and reflection-symmetric momentum distribution. Non-zero magnetic screening is found if the distribution is anisotropic, confirming the results of a closed-time-path-integral approach. We find that the electric and magnetic screening eff

Matthias Blau, Martin O&#39;Loughlin, George Papadopoulos, Arkady A. Tseytlin

We solve closed string theory in all regular homogeneous plane-wave backgrounds with homogeneous NS three-form field strength and a dilaton. The parameters of the model are constant symmetric and anti-symmetric matrices k_{ij} and f_{ij} associated with the metric, and a constant anti-symmetric matrix h_{ij} associated with the NS field strength. In the ligh

J. Engel, M. Bender, J. Dobaczewski, J. H. de Jesus

We use the Skyrme-Hartree-Fock method, allowing all symmetries to be broken, to calculate the time-reversal-violating nuclear Schiff moment (which induces atomic electric dipole moments) in the octupole-deformed nucleus 225Ra. Our calculation includes several effects neglected in earlier work, including self consistency and polarization of the core by the la

D. Ebert, R. N. Faustov, V. O. Galkin

The hyperfine splitting in heavy quarkonia is considered in its relation to the leptonic decay rates with the account of relativistic and radiative corrections. The calculated decay rates agree well with the available experimental data, while the predicted η_c(2S) mass is significantly smaller than the value measured recently by the Belle Collaboration.

Daniel Almehed, Niels R. Walet

We investigate the use of an operatorial basis in a self-consistent theory of large amplitude collective motion. For the example of the pairing-plus-quadrupole model, which has been studied previously at equilibrium, we show that a small set of carefully chosen state-dependent basis operators is sufficient to approximate the exact solution of the problem acc

Dan Abramovich, Jonathan Lubin

The structure of the reduction of an admissible $G$-covering $Y \to X$ at primes $p$ dividing $|G|$ is investigated. Assume $|G|$ is not divisible by $p^2$ and the $p$-Sylow group is normal. Following Raynaud it is shown that there is a group scheme $\cG$ over the smooth locus of $X$ for which $Y$ is still a principal bundle away from the special points. A s

L. Fruchter

The phase diagram of a driven two-dimensional vortex lattice in the presence of dense quasi-point pins is investigated. The transition from the crystal to the liquid is found continuous at intermediate inductions. The correlations in the pseudo random force that allow for an uncomplete unbinding of the dislocations is proposed as a key mechanism to account f

Boris Ischi

Given two complete atomistic lattices L_1 and L_2, we define a set S(L_1,L_2) of complete atomistic lattices by means of three axioms (natural regarding the description of separated quantum compound systems), or in terms of a universal property with respect to a given class of bimorphisms. We call the elements of S(L_1,L_2) weak tensor products of L_1 and L_