October 2006 arXiv papers — page 39

Chris Allton, Chris Maynard, Aurora Trivini, Robert Tweedie

We present preliminary results for the D_s meson spectroscopy study on the 2+1 flavour domain wall fermion lattice configurations, generated with the Iwasaki gauge action at beta=2.13 by the RBC-UKQCD collaboration. The simulations are on 16^3\times32 lattice with L_s=16. We consider the charm quark propagating as an overlap fermion at fixed lattice spacing.

Michael Creutz

For this after dinner talk I intersperse images of real lattices with a discussion of the motivations for lattice gauge theory and some current unresolved issues.

M. Göckeler, R. Horsley, Y. Nakamura, D. Pleiter

Due to improvements in computer performance and algorithms, the rapidly increasing cost for unquenched Wilson-type fermions with lighter quarks has been ameliorated and new simulations are now possible. Here we present results using two flavours of O(a)-improved Wilson fermions for meson decay constants at pseudoscalar masses down to 320MeV. Results are at s

G. Aarts, C. R. Allton, R. Morrin, A. P. O Cais

Charmonium systems in two-flavour QCD at non-zero temperature are studied at, and above the deconfining transition. Using anisotropic lattices the MEM approach is used to extract spectral functions for these channels. By carefully varying some of the irrelevant parameters in the MEM procedure, we confirm that our systematic effects are under control. The eta

M. Göckeler, R. Horsley, H. Perlt, P. E. L. Rakow

We present first results for Wilson coefficients of operators up to first order in the covariant derivatives for the case of Wilson fermions. They are derived from the off-shell Compton scattering amplitude $\mathcal{W}_{μν}(a,p,q)$ of massless quarks with momentum $p$. The Wilson coefficients are classified according to the transformation of the correspondi

CS Collaboration, Y. Kuramashi, S. Aoki, K. -I. Ishikawa

We report on a study of 2+1 flavor lattice QCD with the $O(a)$-improved Wilson quarks on a $16^3\times 32$ lattice at the lattice spacing $1/a\approx 2$GeV employing Luescher's domain-decomposed HMC(LDDHMC) algorithm. This is dedicated to a preliminary study for the PACS-CS project which plans to complete the Wilson-clover $N_f=2+1$ program lowering the

Alexei Garmash

Results from the Belle and BaBar experiments on measurement of the weak angle phi_3 using a Dalitz plot analysis of the KSpi+pi- decay of the neutral D meson from the B+=>D(*)K(*)+ process are presented. The method employs the interference between D0 and D0bar to extract the angle phi_3, strong phase delta and the ratio r of suppressed and allowed amplitudes

G. D. Lafferty

Some recent $τ$-physics results are presented from the BaBar and Belle experiments at the SLAC and KEK B factories, which produce copious numbers of $τ$-lepton pairs. Measurements of the tau mass and lifetime allow to test lepton universality and CPT invariance, while searches for lepton-flavour violation in tau decays are powerful ways to look for physics b

Iver Brevik, John Quiroga Hurtado

We consider dark energy cosmology in a de Sitter universe filled with quantum conformal matter. Our model represents a Gauss-Bonnet model of gravity with contributions from quantum effects. To the General Relativity action an arbitrary function of the GB invariant, f(G), is added, and taking into account quantum effects from matter the cosmological constant

M. Novello, E. Goulart, J. M. Salim, S. E. Perez Bergliaffa

It will be shown that a given realization of nonlinear electrodynamics, used as source of Einstein's equations, generates a cosmological model with interesting features, namely a phase of current cosmic acceleration, and the absence of an initial singularity, thus pointing to a way to solve two important problems in cosmology.

Bogusz Kinasiewicz, Patryk Mach

Two general-relativistic hydrodynamical models are considered: a model of self-gravitating static configurations of perfect fluid and a model of steady accretion of fluid onto a black hole. We generalise analytic results obtained for the original polytropic versions of these models onto a wider class of barotropic equations of state. The knowledge about the

Vladimir S. Mashkevich

It is shown that cosmological spacetime manifold has the structure of a Lie group and a spinor space. This leads naturally to the Minkowski metric on tangent spaces and the Lorentzian metric on the manifold and makes it possible to dispense with double-valued representations.

Henryk Gzyl, Enrique ter Horst, Samuel Malone

In this paper, we describe a general method for constructing the posterior distribution of an option price. Our framework takes as inputs the prior distributions of the parameters of the stochastic process followed by the underlying, as well as the likelihood function implied by the observed price history for the underlying. Our work extends that of Karolyi

Chih-Chun Wang, Sanjeev R. Kulkarni, H. Vincent Poor

This paper focuses on finite-dimensional upper and lower bounds on decodable thresholds of Zm and binary low-density parity-check (LDPC) codes, assuming belief propagation decoding on memoryless channels. A concrete framework is presented, admitting systematic searches for new bounds. Two noise measures are considered: the Bhattacharyya noise parameter and t

Edgar Morin

Why has the problematic of complexity appeared so late? And why would it be justified?

Nathan Keller, Stephen D. Miller, Ilya Mironov, Ramarathnam Venkatesan

MV3 is a new word based stream cipher for encrypting long streams of data. A direct adaptation of a byte based cipher such as RC4 into a 32- or 64-bit word version will obviously need vast amounts of memory. This scaling issue necessitates a look for new components and principles, as well as mathematical analysis to justify their use. Our approach, like RC4&

S. Davatolhagh

The most puzzling aspect of the glass transition observed in laboratory is an apparent decoupling of dynamics from structure. In this paper we recount the implication of various theories of glass transition for the static correlation length in an attempt to reconcile the dynamic and static lengths associate with the glass problem. We argue that a more recent

Anne Parge, Tore Niermann, Michael Seibt, Markus Münzenberg

We present a method to prepare magnetic spin torque devices of low specific resistance in a one step lithography process. The quality of the pillar devices is demonstrated for a standard magnetic double layer device. For single layer devices, we found hysteretic switching and a more complex dynamical excitation pattern in higher fields. A simple model to exp

S. Cox, J. C. Lashley, E. Rosten, J. Singleton

The nature of the phase transitions in La$_{1-x}$Ca$_x$MnO$_3$ and Pr$_{0.48}$Ca$_{0.52}$MnO$_3$ has been probed using heat capacity and magnetisation measurements. The phase transition associated with the onset of the stripe phase has been identified as second order. The model of a Peierls transition in a disordered system (a `dirty' Peierls transition)

E. J. R. Oliveira, A. T. da Cunha Lima, M. A. Boselli, G. M. Sipahi

The occurrence of inhomogeneous spin-density distribution in multilayered ferromagnetic diluted magnetic semiconductor nanostructures leads to strong dependence of the spin-polarized transport properties on these systems. The spin-dependent mobility, conductivity and resistivity in (Ga,Mn)As/GaAs,(Ga,Mn)N/GaN, and (Si,Mn)/Si multilayers are calculated as a f

P. J. Baker, S. J. Blundell, F. L. Pratt, T. Lancaster

We report muon spin relaxation (muSR) and magnetic susceptibility investigations of two Ti3+ chain compounds which each exhibit a spin gap at low temperature, NaTiSi2O6 and TiOCl. From these we conclude that the spin gap in NaTiSi2O6 is temperature independent, with a value of 2*Delta=660(50)K, arising from orbital ordering at Too = 210K; the associated stru

Z. Yusof, B. O. Wells, T. Valla, P. D. Johnson

We present an angle-resolved photoemission spectroscopy (ARPES) study of a Mott-Hubbard-type bismuth cobaltate system across a metal-insulator transition. By varying the amount of Pb substitution, and by doping with Sr or Ba cation, a range of insulating to metallic properties is obtained. We observe a systematic change in the spectral weight of the coherent

D. M. Sagar, A. A. Tsvetkov, D. Fausti, S. van Smaalen

The charge density wave system K_0.3MoO_3 has been studied using variable energy pump-probe spectroscopy, ellipsometry, and inelastic light scattering. The observed transient reflectivity response exhibits quite a complex behavior, containing contributions due to quasi particle excitations, coherent amplitudons and phonons, and heating effects. The generatio

Giulio Casati, Carlos Mejia-Monasterio

We discuss the problem of heat conduction in classical and quantum low dimensional systems from a microscopic point of view. At the classical level we provide convincing numerical evidence for the validity of Fourier law of heat conduction in linear mixing systems, i.e. in systems without exponential instability. At the quantum level, where motion is charact

R. J. Magyar, V. Mujica, M. Marquez, C. Gonzalez

Magnetism in bare uncapped gold nano-clusters is explored from a density functional theory perspective with scalar relativistic effects included via the pseudo-potential. The computed electronic structures of various nano-clusters reveal that permanent size-dependent spin-polarization appears without geometry relaxation for bare clusters even though bulk gol

Pasquale Calabrese, Andrea Gambassi

Within the universality class of ferromagnetic vector models with O(n) symmetry and purely dissipative dynamics, we study the non-equilibrium critical relaxation from a magnetized initial state. Transverse correlation and response functions are exactly computed for Gaussian fluctuations and in the limit of infinite number n of components of the order paramet

J. -E. Wegrowe, C. Ciornei, H. -J. Drouhin

Spin-transfer is a typical spintronics effect that allows a ferromagnetic layer to be switched by spin-injection. Most of the experimental results about spin transfer are described on the basis of the Landau-Lifshitz-Gilbert equation of the magnetization, in which additional current-dependent damping factors are added, and can be positive or negative. The or

W. M. Temmerman, A. Svane, L. Petit, M. Lueders

A review is given of pressure induced valence transitions in f-electron systems calculated with the self-interaction corrected local spin density (SIC-LSD) approximation. These calculations show that the SIC-LSD is able to describe valence changes as a function of pressure or chemical composition. An important finding is the dual character of the f-electrons

R. Gommers, S. Denisov, F. Renzoni

We investigate experimentally the route to quasiperiodicity in a driven ratchet for cold atoms, and examine the relationship between symmetries and transport while approaching the quasiperiodic limit. Depending on the specific form of driving, quasiperiodicity results in the complete suppression of transport, or into the restoration of the symmetries which h

Florian Baumann, Andrea Gambassi

We investigate some aspects of the ageing behavior observed in the contact process after a quench from its active phase to the critical point. In particular we discuss the scaling properties of the two-time response function and we calculate it and its universal ratio to the two-time correlation function up to first order in the field-theoretical epsilon-exp

E. Majernikova, S. Shpyrko

We studied complex spectra of spin-two boson systems represented by E$\otimes$e and E$\otimes (b_1+b_2)$ Jahn-Teller models. For E$\otimes$e, at particular rotation quantum numbers we found a coexistence of up to three regions of the spectra, (i) the dimerized region of long-range ordered (extended) pairs of oscillating levels, (ii) the short-range ordered (

S. E. Krasavin

The residual resistivity $ρ$ in metals caused by wedge disclination dipoles is studied in the framework of the Drude formula. It is shown that $ρ\sim L^{-p}$ with $p=3$ for biaxial and $p=2$ for uniaxial dipoles ($L$ is a size of dipole arm)

A. J. Archer, D. Pini, R. Evans, L. Reatto

Using a simple mean-field density functional theory theory (DFT), we investigate the structure and phase behaviour of a model colloidal fluid composed of particles interacting via a pair potential which has a hard core of diameter $σ$, is attractive Yukawa at intermediate separations and repulsive Yukawa at large separations. We analyse the form of the asymp

Brandon P. van Zyl, D. A. W. Hutchinson, Melodie Need

We investigate a density-functional theory (DFT) approach for an unpolarized trapped dilute Fermi gas in the unitary limit . A reformulation of the recent work of T. Papenbrock [Phys. Rev. A, {\bf 72}, 041602(R) (2005)] in the language of fractional exclusion statistics allows us to obtain an estimate of the universal factor, $ξ_{3D}$, in three dimensions (3

P. Lecheminant, K. Totsuka

We investigate the low-energy properties of a generalized quantum sine-Gordon model in one dimension with a self-dual symmetry. This model describes a class of quantum phase transitions that stems from the competition of different orders. This SU(N) self-dual sine-Gordon model is shown to be equivalent to an SO(N)_2 conformal field theory perturbed by a curr

Ludovic Berthier, Walter Kob

We use a standard Monte-Carlo algorithm to study the slow dynamics of a binary Lennard-Jones glass-forming mixture at low temperature. We find that Monte-Carlo is by far the most efficient way to simulate a stochastic dynamics since relaxation is about 10 times faster than in Brownian Dynamics and about 30 times faster than in Stochastic Dynamics. Moreover,

B. Padmanabhan, H. L. Bhat, Suja Elizabeth, Sahana Roessler

The critical properties at the ferromagnetic - paramagnetic transition have been analysed from data of static magnetization measurements on single crystals of Pr1-xPbxMnO3, for x = 0.23 and x = 0.30. In Pr1-xPbxMnO3 the ferromagnetic ordering and the metal-insulator transition do not coincide in parts of the phase diagram. The crystal with x = 0.23 is a ferr

Shan He, Sheng Li, Hongru Ma

We investigate the percentage of delivering capacities that are actually consumed in a typical traffic dynamics where the capacities are uniformly assigned over a scale-free network. Theoretical analysis, as well as simulations, reveal that there are a large number of idle nodes under both free and weak congested state of the network. It is worth noting that

M. Kiguchi, D. Djukic, J. M. van Ruitenbeek

We have measured the effect of bonding of a CO molecule on the conductance of Au, Cu, Pt, and Ni atomic contacts at 4.2 K. When CO gas is admitted to the metal nano contacts, a conductance feature appears in the conductance histogram near 0.5 of the quantum unit of conductance, for all metals. For Au, the intensity of this fractional conductance feature can

T. Valla, T. E. Kidd, Z. -H. Pan, A. V. Fedorov

In conventional metals, electron-phonon coupling, or the phonon-mediated interaction between electrons, has long been known to be the pairing interaction responsible for the superconductivity. The strength of this interaction essentially determines the superconducting transition temperature TC. One manifestation of electron-phonon coupling is a mass renormal

Takayoshi Tanaka, Sumio Ishihara

We study dilution effects in a Mott insulating state with quantum orbital degree of freedom, termed the two-dimensional orbital compass model. This is a quantum and two-dimensional version of the orbital model where the interactions along different bond directions cause frustration between different orbital configurations. A long-range correlation of a kind

Julien Tailleur, Sorin Tanase-Nicola, Jorge Kurchan

Hamilton's equations with noise and friction possess a hidden supersymmetry, valid for time-independent as well as periodically time-dependent systems. It is used to derive topological properties of critical points and periodic trajectories in an elementary way. From a more practical point of view, the formalism provides new tools to study the reaction p

Zhang Xue-Guang, Deborah Dultzin-Hacyan, Wang Ting-Gui

We study the size of BLRs of low luminosity Active Galactic Nuclei, also called 'dwarf AGN', defined as having ($L_{Hα}\le10^{41}{\rm erg\cdot s^{-1}}$)). We more than double the sample size analyzed previously (Wang & Zhang 2003, hereafter Paper I). In this study we first confirm our previous result that the sizes of BLRs of low luminosity AGN are l

R. Mukherjee, E. V. Gotthelf, J. P. Halpern

We present an analysis of Chandra ACIS observations of the field of TeV J2032+4130, the first unidentified TeV source, detected serendipitously by HEGRA. This deep (48.7 ksec) observation of the field follows up on an earlier 5 ksec Chandra director's discretionary observation. Of the numerous point-like X-ray sources in the field, the brightest are show

Young-Rae Kim, Rupert Croft

We investigate the possibility of probing dark energy by measuring the isotropy of the galaxy cluster autocorrelation function (an Alcock-Paczynski test). The correlation function is distorted in redshift space because of the cluster peculiar velocities, but if these are known and can be subtracted, the correlation function measurement becomes in principle a

Kyoko Matsushita, Hans Boehringer, Isao Takahashi, Yasushi Ikebe

The abundances of O, Mg, Si and Fe in the intracluster medium of the Centaurus cluster are derived. The Fe abundance has a negative radial gradient. In solar units, the Si abundance is close to the Fe abundance, while the O and Mg abundances are much smaller. The high Fe/O and Si/O ratio indicate that metal supply from supernovae Ia is important and supernov

P. Erni, G. A. Tammann

Type Ia Supernovae (SNe Ia) are the best standard candles known today. At high redshift ($z\sim1$) SNe Ia are used to determine the Cosmological Constant Lambda with great success. However the most serious concern is raised by thepossible luminosity evolution of the SNe Ia explosion itself, i.e., that their intrinsic luminosity might vary with the look-back

Balázs Mikóczi

We present here a complete list of contributions to the gravitational wave frequency evolution from compact binaries on circular orbits up to the second post-Newtonian order by including the interaction of magnetic dipole moments, quadrupole-monopole interactions together with the spin-orbit, the spin-spin and the self-interaction spin contributions. We appl

Giacomo Beccari, Francesco R. Ferraro, Barbara Lanzoni, Michele Bellazzini

We have used a set of archived Hubble Space Telescope/ACS images to probe the evolved populations of the globular cluster 47 Tucanae. We find an excess of Asymptotic Giant Branch (AGB) stars in the cluster core. We interpret this feature as the signature of an extra-population likely made by the progeny of massive stars originated by the evolution of binary

Zoltán Keresztes, Balázs Mikóczi

In this work we consider compact binaries on eccentric orbit under the spin-spin interaction. Using the post-Newtonian formalism, the binaries undergo a perturbed Keplerian motion. Here we investigate only the radial motion and derive the contribution of the second post-Newtonian order spin-spin effect to the solution.

Jonathan D. Slavin

We discuss the thermal evaporation of tiny HI clouds in the interstellar medium. Cold neutral clouds will take ~10^6 - 10^7 yr to evaporate if they are embedded in warm neutral gas and about half as long if embedded in hot gas. Heat flux saturation effects severely reduce the evaporation rate of tiny cold neutral medium (CNM) clouds into hot gas. For CNM clo

Balázs Mikóczi, Zoltán Keresztes

The angular and the radial parts of the dynamics of the perturbed Kepler motion are separable in many important cases. In this paper we study the radial motion and its parametrizations. We develop in detail a generalized eccentric anomaly parametrization and a procedure of computing a generic class of integrals based on the residue theorem. We apply the form

Timothy C. Beers, Tiago Almeida, Silvia Rossi, Ronald Wilhelm

We present coordinates and available photometric information (either from previous or recent broadband UBV observations, and near-infrared photometry from the 2MASS Point Source Catalog) for 12056 stars (11516 of which are unique) identified in the HK Survey of Beers and colleagues as candidate field horizontal-branch or A-type stars. These stars, in the app

R. Hirschi

A series of fast rotating models at very low metallicity (Z=1e-8) was computed in order to explain the surface abundances observed at the surface of CEMP stars, in particular for nitrogen. The main results are the following: - Strong mixing occurs during He--burning and leads to important primary nitrogen production. - Important mass loss takes place in the

Jeffrey L. Linsky, Marc Gagne, Anna Mytyk, Mark McCaughrean

We present and analyze the first high-resolution X-ray images ever obtained of the Eagle Nebula star-forming region. On 2001 July 30 the Chandra X-ray Observatory obtained a 78 ks image of the Eagle Nebula (M 16) that includes the core of the young galactic cluster NGC 6611 and the dark columns of dust and cold molecular gas in M 16 known as the Pillars of C

Stefano Bianchi, Marco Chiaberge, Enrico Piconcelli, Matteo Guainazzi

We performed a detailed analysis of the Chandra and HST images of the Seyfert 2 galaxy, NGC7582. The dust lane, as mapped by the HST NIR and optical images, strongly influences the morphology of the soft X-ray emission, being spatially coincident with excess of X-ray absorption. Two 'hot spots', i.e. regions where emission from higher ionization stag

R. Hirschi, G. Meynet, A. Maeder

We calculated pre-supernova evolution models of single rotating massive stars. These models reproduce observations during the early stages of the evolution very well, in particular Wolf--Rayet (WR) populations and ratio between type II and type Ib,c supernovae at different metallicities (Z). Using these models we found the following results concerning long a

K. Sinha

Identification of Fraunhofer lines with the known atomic and molecular absorbers and predictions leading to such an effort has been a challenging area of study crowned with occasional success. Such studies have also lead, amongst other things to (i) a determination of abundances of elements and that of their isotopes (ii) valuable information on model atmosp

Uta Grothkopf, Sarah Stevens-Rayburn

This paper analyzes the performance of observatories based on the so-called h-index (Hirsch 2005), a new, easy-to-use parameter that quantifies scientists' research impact and relevance. Compared to other bibliometric criteria, like total number of publications or citations, the h-index is less biased. Using NASA's Astrophysics Data System (ADS), we

P. A. Jones, M. R. Cunningham, P. D. Godfrey, D. M. Cragg

We have used the Australia Telescope Compact Array to conduct a search for the simplest amino acid, glycine (conformers I and II), and the simple chiral molecule propylene oxide at 3-mm in the Sgr B2 LMH. We searched 15 portions of spectrum between 85 and 91 GHz, each of 64 MHz bandwidth, and detected 58 emission features and 21 absorption features, giving a

Mark T. Reynolds, Paul J. Callanan, Alexei V. Filippenko

We present Keck K-band photometry and low-resolution H & K-band spectroscopy of the X-ray nova GRO J0422+32 obtained while the system was in the quiescent state. No clear ellipsoidal modulation is present in the light curve, which is instead dominated by a strong flickering component. In the K-band we observe strong Br_gamma emission, with an equivalent widt

K. Saha, C. J. Jog

Recent observations have shown that most of the warps in the disk galaxies are asymmetric. However there exists no generic mechanism to generate these asymmetries in warps. We have shown that a rich variety of possible asymmetries in the z-distribution of the spiral galaxies can naturally arise due to a dynamical wave interference between the first two bendi

C. Itoh, R. Enomoto, S. Yanagita, T. Yoshida

The CANGAROO-II telescope observed sub-TeV gamma-ray emission from the nearby starburst galaxy NGC 253. The emission region was extended with a radial size of 0.3-0.6 degree. On the contrary, H.E.S.S could not confirm this emission and gave upper limits at the level of the CANGAROO-II flux. In order to resolve this discrepancy, we analyzed new observational

V. Boucher, J. -M. Gerard, P. Vandergheynst, Y. Wiaux

A Nordtvedt effect at cosmological scales affects the acoustic oscillations imprinted in the cosmic microwave background. The gravitational baryonic mass density of the universe is inferred at the first peak scale from WMAP data. The independent determination of the inertial baryonic mass density through the measurement of the deuterium abundance in the fram

Dapeng Zhan

We define a family of stochastic Loewner evolution-type processes in finitely connected domains, which are called continuous LERW (loop-erased random walk). A continuous LERW describes a random curve in a finitely connected domain that starts from a prime end and ends at a certain target set, which could be an interior point, or a prime end, or a side arc. I

F. W. Payne, Wei Jiang, J. W. Emmert, Jun Deng

We have studied the magnetic properties of free cobalt clusters in two semi-independent Stern-Gerlach deflection experiments at temperatures between 60 and 307 K. We find that clusters consisting of 13 to 200 cobalt atoms exhibit behavior that is entirely consistent with superparamagnetism, though complicated by finite-system fluctuations in cluster temperat

Dan Batcheldor, Alessandro Marconi, David Merritt, David J. Axon

Using the extended J, H and K magnitudes provided by the 2MASS data archive, we consider the position of brightest cluster galaxies (BCGs) in the observed relations between inferred supermassive black hole (SMBH) mass and the host galaxy properties, as well as their position in the stellar velocity dispersion and luminosity (sigma-L) relation, compared to E

Zach Teitler

M. Mustata used jet schemes to compute the multiplier ideals of reduced hyperplane arrangements. We give an alternate proof using a log resolution, which is simpler and allows us to consider non-reduced arrangements. By applying the idea of wonderful models introduced by De Concini--Procesi, we also simplify the result.

Piotr Korcyl

We analyze a supersymmetric system with four flat directions. We observe several interesting properties, such as the coexistence of the discrete and continuous spectrum in the same range of energies. We also solve numerically the classical counterpart of this system. A similar analysis is then done for an alike, but non-supersymmetric system. The comparison

P. Chang, E. Quataert, N. Murray

We argue that the X-ray and UV flux illuminating the parsec-scale accretion disk around luminous active galactic nuclei (AGN) is super-Eddington with respect to the local far-infrared dust opacity. The far infrared opacity may be larger than in the interstellar medium of the Milky Way due to a combination of supersolar metallicity and the growth of dust grai

Daniel Lemire

The running maximum-minimum (max-min) filter computes the maxima and minima over running windows of size w. This filter has numerous applications in signal processing and time series analysis. We present an easy-to-implement online algorithm requiring no more than 3 comparisons per element, in the worst case. Comparatively, no algorithm is known to compute t

K. Aker, Sz. Szabo

We study Nahm transformation for parabolic Higgs bundles on the projective line \PP^1, with logarithmic singularities on a finite set P. Such a Higgs bundle can be given by its spectral data: a Hirzebruch surface Z together with a coherent sheaf M on Z, supported in dimension 1 and away from infinity. We describe the transform in terms of these data. The mai

Scott Funkhouser

According to a model of quantum cosmology the maximum number of degrees of freedom allowed in our three dimensions was determined by the size of seven extra dimensions in an initial excited state before inflation. The size of the extra dimensions can be inferred from a simple scheme for unifying the strong force and gravity. Coupled with the Bekenstein-Hawki

David Berenstein, Samuel Pinansky

This paper discusses the minimal quiver gauge theory embedding of the standard model that could arise from brane world type string theory constructions. It is based on the low energy effective field theory of D-branes in the perturbative regime. The model differs from the standard model by the addition of one extra massive gauge boson, and contains only one

Augustin-Liviu Mare

Let q_1, ..., q_n be some variables and set K:=Z[q_1, ..., q_n]/(q_1q_2...q_n). We show that there exists a K-bilinear product \star on H^*(F_n;Z)\otimes K which is uniquely determined by some quantum cohomology like properties (most importantly, a degree two relation involving the generators and an analogue of the flatness of the Dubrovin connection). Then

Asantha Cooray

The non-Gaussianity of initial perturbations provides information on the mechanism that generated primordial density fluctuations. The expected non-Gaussianity for slow-roll inflationary models is well below the ultimate detection level with cosmic microwave background (CMB) anisotropies or large-large structure at low redshifts. We find that 21-cm backgroun

Maryam Arabsalmani, Amir Aghamohammadi

It is shown, concerning equivalent classes, that on a one-dimensional lattice with nearest neighbor interaction, there are only four independent models possessing double-shocks. Evolution of the width of the double-shocks in different models is investigated. Double-shocks may vanish, and the final state is a state with no shock. There is a model for which at

Matthew S. Tiscareno, Joseph A. Burns, Philip D. Nicholson, Matthew M. Hedman

We describe a powerful signal processing method, the continuous wavelet transform, and use it to analyze radial structure in Cassini ISS images of Saturn's rings. Wavelet analysis locally separates signal components in frequency space, causing many structures to become evident that are difficult to observe with the naked eye. Density waves, generated at

R. Carretero-Gonzalez, N. Whitaker, P. G. Kevrekidis, D. J. Frantzeskakis

We study the formation of vortices, vortex necklaces and vortex ring structures as a result of the interference of higher-dimensional Bose-Einstein condensates (BECs). This study is motivated by earlier theoretical results pertaining to the formation of dark solitons by interfering quasi one-dimensional BECs, as well as recent experiments demonstrating the f

Ferenc Szöllosi

The purpose of this paper is to introduce new parametric families of complex Hadamard matrices in two different ways. First, we prove that every real Hadamard matrix of order N>=4 admits an affine orbit. This settles a recent open problem of Tadej and Zyczkowski, who asked whether a real Hadamard matrix can be isolated among complex ones. In particular, we a

Don N. Page

Observations that we are highly unlikely to be vacuum fluctuations suggest that our universe is decaying at a rate faster than the asymptotic volume growth rate, in order that there not be too many observers produced by vacuum fluctuations to make our observations highly atypical. An asymptotic linear e-folding time of roughly 16 Gyr (deduced from current me

P. Ferrero, S. F. Sanchez, D. A. Kann, S. Klose

We report early follow-up observations of the error box of the short burst 050813 using the telescopes at Calar Alto and at Observatorio Sierra Nevada (OSN), followed by deep VLT/FORS2 I-band observations obtained under very good seeing conditions 5.7 and 11.7 days after the event. Neither a fading afterglow, nor a rising SN component was found, so the poten

A. Brooks Harris

This paper represents a detailed instruction manual for constructing the Landau expansion for magnetoelectric coupling in incommensurate ferroelectric magnets. The first step is to describe the magnetic ordering in terms of symmetry adapted coordinates which serve as complex valued magnetic order parameters whose transformation properties are displayed. In s

Nalini Anantharaman, Stéphane Nonnenmacher

We study the high-energy eigenfunctions of the Laplacian on a compact Riemannian manifold with Anosov geodesic flow. The localization of a semiclassical measure associated with a sequence of eigenfunctions is characterized by the Kolmogorov-Sinai entropy of this measure. We show that this entropy is necessarily bounded from below by a constant which, in the

Kurtis A. Williams

We examine new methods of producing and analyzing the empirical initial-final mass relation for open cluster white dwarfs (WDs). We re-determine initial and final masses for the complete sample of published cluster WDs and then pare this sample using stringent criteria. We create an empirical initial-final mass relation by binning all WDs in individual clust

David B. Massey

If $\Adot$ is a bounded, constructible complex of sheaves on a complex analytic space $X$, and $f:X\to\C$ and $g:X\to\C$ are complex analytic functions, then the iterated vanishing cycles $ϕ_g[-1](ϕ_f[-1]\Adot)$ are important for a number of reasons. We give a formula for the stalk cohomology $H^*(ϕ_g[-1]ϕ_f[-1]\Adot)_x$ in terms of relative polar curves, al

Michael R. Douglas, Shamit Kachru

We review recent work in which compactifications of string and M theory are constructed in which all scalar fields (moduli) are massive, and supersymmetry is broken with a small positive cosmological constant, features needed to reproduce real world physics. We explain how this work implies that there is a ``landscape'' of string/M theory vacua, perh

Niklas Beisert

We investigate the integrable structure of spin chain models with centrally extended su(2|2) and psu(2,2|4) symmetry. These chains have their origin in the planar AdS/CFT correspondence, but they also contain the one-dimensional Hubbard model as a special case. We begin with an overview of the representation theory of centrally extended su(2|2). These result

Kaya Mori, Jeremy S. Heyl

Recent observations and theoretical investigations of neutron stars indicate that their atmospheres consist not of hydrogen or iron but possibly other elements such as helium. We calculate the ionization and dissociation equilibrium of helium in the conditions found in the atmospheres of magnetized neutron stars. For the first time this investigation include

The BABAR Collaboration, B. Aubert

Using 65 million $Υ(4S)\to B\bar{B}$ events collected with the BABAR detector at the PEP-II $e^{+}e^{-}$ storage ring at the Stanford Linear Accelerator Center, we measure the color-favored branching fractions ${\cal B}(\bar{B^{0}} \to D^{+} π^{-}) = (2.55 \pm 0.05 \pm 0.16)\times 10^{-3}$, ${\cal B}(\bar{B^{0}} \to D^{*+} π^{-}) = (2.79 \pm 0.08 \pm 0.17)\t

Geir T. Helleloid

This survey on the automorphism groups of finite p-groups focuses on three major topics: explicit computations for familiar finite p-groups, such as the extraspecial p-groups and Sylow p-subgroups of Chevalley groups; constructing p-groups with specified automorphism groups; and the discovery of finite p-groups whose automorphism groups are or are not p-grou

Tadayuki Watanabe

M. Kontsevich constructed universal characteristic classes of smooth bundles with fiber a framed odd-dimensional integral homology sphere. In dimension 3, they are known to give a universal finite type invariants of homology 3-spheres. However, they have not been well understood for higher fiber dimensions. The purpose of the present paper is twofold. First,

Liang Kong

We introduce the notions of open-closed field algebra and open-closed field algebra over a vertex operator algebra V. In the case that V satisfies certain finiteness and reductivity conditions, we show that an open-closed field algebra over V canonically gives an algebra over a $\C$-extension of the Swiss-cheese partial operad. We also give a tensor categori

Sheldon Stone

I report preliminary CLEO-c results on purely leptonic decays of the Ds using 195/pb of data at 4.170 GeV. We measure fDs = 280.1 +/- 11.6 +/- 6.0 MeV, and fDs/fD+ = 1.26 +/- 0.11 +/- 0.03.

Molly S. Peeples, A. Z. Bonanos, D. L. DePoy, K. Z. Stanek

We present a re-analysis of our H- and K-band photometry and light-curves for GCIRS 16SW, a regular periodic source near the Galactic center. These data include those presented by DePoy et al. (2004); we correct a sign error in their reduction, finding GCIRS 16SW to be an eclipsing binary with no color variations. We find the system to be an equal mass overc

Paul Dempsey, Peter Duffy

Relativistic shocks provide an efficient method for high-energy particle acceleration in many astrophysical sources. Multiple shock systems are even more effective and of importance, for example, in the internal shock model of gamma-ray bursts. We investigate the reacceleration of pre-existing energetic particles at such relativistic internal shocks by the f

E. Louis, J. A. Verges, F. Guinea, G. Chiappe

We investigate the size scaling of the conductance of surface disordered graphene sheets of width W and length L. Metallic leads are attached to the sample ends across its width. At E ~ 0, the conductance scales with the system size as follows: i) For constant W/L, it remains constant as size is increased, at a value which depends almost lineally on that rat

J. Elisenda Grigsby

We introduce a simple combinatorial method for computing all versions of the knot Floer homology of the preimage of a two-bridge knot K(p,q) inside its double-branched cover, -L(p,q). The 4-pointed genus 1 Heegaard diagram we obtain looks like a twisted version of the toroidal grid diagrams recently introduced by Manolescu, Ozsvath, and Sarkar. We conclude w

2 Collaboration, R. R. Akhmetshin, V. M. Aulchenko, V. Sh. Banzarov

We present a measurement of the pion form factor based on e+e- annihilation data from the CMD-2 detector in the energy range 0.6<sqrt(s)<1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five times larger than that used in our previous measurement.

Abdelmalek Abdesselam

We give a rigorous nonperturbative construction of a massless discrete trajectory for Wilson&#39;s exact renormalization group. The model is a three dimensional Euclidean field theory with a modified free propagator. The trajectory realizes the mean field to critical crossover from the ultraviolet Gaussian fixed point to an analog recently constructed by Bry