March 2009 arXiv papers — page 33

S. J. C. Yates, A. M. Baryshev, J. J. A. Baselmans, B. Klein

Microwave Kinetic Inductance Detectors (MKIDs) have great potential for large very sensitive detector arrays for use in, for example, sub-mm imaging. Being intrinsically readout in the frequency domain, they are particularly suited for frequency domain multiplexing allowing $\sim$1000s of devices to be readout with one pair of coaxial cables. However, this m

J. P. Bouchaud

We define what "Price Impact" means, and how it is measured and modelled in the recent literature. Although this notion seems to convey the idea of a forceful and intuitive mechanism, we discuss why things might not be that simple. Empirical studies show that while the correlation between signed order flow and price changes is strong, the impact of t

Liang Fu, C. L. Kane

We propose two experiments to probe the Majorana fermion edge states that occur at a junction between a superconductor and a magnet deposited on the surface of a topological insulator. Combining two Majorana fermions into a single Dirac fermion on a magnetic domain wall allows the neutral Majorana fermions to be probed with charge transport. We will discuss

Sachin Kadloor, Raviraj Adve

We consider a system with a single base station communicating with multiple users over orthogonal channels while being assisted by multiple relays. Several recent works have suggested that, in such a scenario, selection, i.e., a single relay helping the source, is the best relaying option in terms of the resulting complexity and overhead. However, in a multi

Ian A. B. Strachan

When written in terms of $\vartheta$-functions, the classical Frobenius-Stickelberger pseudo-addition formula takes a very simple form. Generalizations of this functional identity are studied, where the functions involved are derivatives (including derivatives with respect to the modular parameter) of the elliptic trilogarithm function introduced by Beilinso

Hajime Sotani

An alternative theory of gravity has recently been proposed by Bekenstein, named Tensor-Vector-Scalar (TeVeS) theory, which can explain many galactic and cosmological observations without the need for dark matter. Whilst this theory passes basic solar system tests, and has been scrutinized with considerable detail in other weak-field regimes, comparatively l

G. D. Thompson, N. A. Levenson, S. A. Uddin, M. M. Sirocky

We use mid-infrared spectroscopy of unobscured active galactic nuclei (AGNs) to reveal their native dusty environments. We concentrate on Seyfert 1 galaxies, observing a sample of 31 with the Infrared Spectrograph aboard the Spitzer Space Telescope, and compare them with 21 higher-luminosity quasar counterparts. Silicate dust reprocessing dominates the mid-i

C. Allende Prieto, I. Hubeny, J. A. Smith

The spectral energy distributions for pure-hydrogen (DA) hot white dwarfs can be accurately predicted by model atmospheres. This makes it possible to define spectrophotometric calibrators by scaling the theoretical spectral shapes with broad-band photometric observations -- a strategy successfully exploited for the spectrographs onboard the Hubble Space Tele

Kingshook Biswas

We study the closed group of homeomorphisms of the boundary of real hyperbolic space generated by a cocompact Kleinian group $G_1$ and a quasiconformal conjugate $h^{-1}G_2 h$ of a cocompact group $G_2$. We show that if the conjugacy $h$ is not conformal then this group contains a non-trivial one parameter subgroup. This leads to rigidity results; for exampl

Marta Calvi

LHCb is the experiment at the Large Hadron Collider devoted to studies of new phenomena in CP violation and in rare decays. This review summarizes the status of the experiment in the imminence of the data taking, the prospects for the first measurements and highlights of its full physics program.

D. V. Berkov, N. L. Gorn

We present numerical simulation studies of the steady-state magnetization dynamics driven by a spin-polarized current in a point contact geometry for the case of a relatively large contact diameter (D = 80 nm) and small external field (H = 30 Oe). We show, that under these conditions the magnetization dynamics is qualitatively different from the dynamics obs

Gabriele La Nave, Gang Tian

In this paper, we first show an interpretation of the Kähler-Ricci flow on a manifold $X$ as an exact elliptic equation of Einstein type on a manifold $M$ of which $X$ is one of the (Kähler) symplectic reductions via a (non-trivial) torus action. There are plenty of such manifolds (e.g. any line bundle on $X$ will do). Such an equation is called $V$-soliton

C. A. Garcia Canal, S. J. Sciutto, T. Tarutina

A comparative analysis of the secondary particles output of the main hadronic interaction packages used in simulations of extensive air showers is presented. Special attention is given to the study of events with very energetic leading secondary particles, including diffractive interactions.

Alexei G. Myasnikov, Mahmood Sohrabi

In this paper we find a characterization for groups elementarily equivalent to a free nilpotent group $G$ of class 2 and arbitrary finite rank.

Yu Chen, N. Regnault, R. Ferreira, Bang-Fen Zhu

We report a theoretical study of the carrier relaxation in a quantum cascade laser (QCL) subjected to a strong magnetic field. Both the alloy (GaInAs) disorder effects and the Frohlich interaction are taken into account when the electron energy differences are tuned to the longitudinal optical (LO) phonon energy. In the weak electron-phonon coupling regime,

Riad Nechache, Catalin Harnagea, Louis-Philippe Carignan, Olivier Gautreau

The influence of the deposition pressure PO2 and substrate temperature TS during the growth of Bi2FeCrO6 thin films grown by pulsed laser deposition has been investigated. It is found that the high volatility of Bi makes the deposition very difficult and that the growth of pure Bi2FeCrO6 thin films on SrTiO3 substrates is possible only in a narrow deposition

Kingshook Biswas

We use techniques of tube-log Riemann surfaces due to R.Perez-Marco to construct a hedgehog containing smooth $C^{\infty}$ combs. The hedgehog is a common hedgehog for a family of commuting non-linearisable holomorphic maps with a common indifferent fixed point. The comb is made up of smooth curves, and is transversally bi-Hölder regular.

A. Horneffer, L. Bähren, S. Buitink, H. Falcke

Air showers from cosmic rays emit short, intense radio pulses. LOFAR is a new radio telescope, that is being built in the Netherlands and Europe. Designed primarily as a radio interferometer, the core of LOFAR will have a high density of radio antennas, which will be extremely well calibrated. This makes LOFAR a unique tool for the study of the radio propert

Aldo Conca

We present results, both old and new, concerning Koszul and G-quadratic properties of algebras associated with points, curves, cubics and spaces of quadrics of low codimension.

Kingshook Biswas

In the study of the local dynamics of a germ of diffeomorphism fixing the origin in C, an important problem is to determine the centralizer of the germ in the group Diff(C,0) of germs of diffeomorphisms fixing the origin. When the germ is not of finite order, then the centralizer is abelian, and hence a maximal abelian subgroup of Diff(C,0). Conversely any m

Simone Recchi, Francesco Calura, Pavel Kroupa

The chemical evolution of galaxies is investigated within the framework of the star formation rate (SFR) dependent integrated galactic initial mass function (IGIMF). We study how the global chemical evolution of a galaxy and in particular how [alpha/Fe] abundance ratios are affected by the predicted steepening of the IGIMF with decreasing SFR. We use analyti

Kingshook Biswas

Perez-Marco proved the existence of non-trivial totally invariant connected compacts called hedgehogs near the fixed point of a nonlinearizable germ of holomorphic diffeomorphism. We show that if two nonlinearisable holomorphic germs with a common indifferent fixed point have a common hedgehog then they must commute. This allows us to establish a corresponde

Christine A. Aidala

The Relativistic Heavy Ion Collider (RHIC) has brought the study of spin effects in hadronic collisions to a new energy regime. In conjunction with other experiments at facilities around the world, much can be learned from the high-energy polarized proton collisions RHIC provides, allowing the collider to serve as a powerful tool to continue to understand th

D. Y. Tang, H. Zhang, L. M. Zhao, X. Wu

We report on the experimental observation of a novel type of polarization locked vector soliton in a passively mode-locked fiber laser. The vector soliton is characterized by that not only the two orthogonally polarized soliton components are phase locked, but also one of the components has a double-humped intensity profile. Multiple such phase-locked high o

Jacco Th. van Loon, Snezana Stanimirovic, Mary Putman, Joshua E. G. Peek

We present 21-cm observations of four Galactic globular clusters, as part of the on-going GALFA-HI Survey at Arecibo. We discovered a peculiar HI cloud in the vicinity of the distant (109 kpc) cluster Pal 4, and discuss its properties and likelihood of association with the cluster. We conclude that an association of the HI cloud and Pal 4 is possible, but th

A. P. Petrovic, Y. Fasano, R. Lortz, C. Senatore

Using scanning tunnelling microscopy at 400mK, we have obtained maps of around 100 vortices in SnMo6S8 from 2 - 9T. The orientational and positional disorder at 5 and 9T show that these are the first large-scale images of a vortex glass. At higher temperature a magnetisation peak effect is observed, whose upper boundary coincides with a lambda anomaly in the

Oscar Perdomo

In this paper we provide a family of algebraic space-like surfaces in the three dimensional anti de Sitter space that shows that this Lorentzian manifold admits algebraic maximal examples of any order. Then, we classify all the space-like order two algebraic maximal hypersurfaces in the anti de Sitter $N$-dimensional space. Finally, we provide two families o

Jianqiang Zhao, Xia Zhou

In this paper we shall prove that every Witten multiple zeta value of weight w>3 attached to sl(4) at nonnegative integer arguments is a finite rational linear combinations of MZVs of the weight w and the depths three or less, except for the nine irregular cases where the Riemann zeta value zeta(w-2) and the double zeta values of weight w-1 and depth <3 are

Jean Berstel, Luc Boasson, Olivier Carton, Isabelle Fagnot

We show that there exists an uniformly recurrent infinite word whose set of factors is closed under reversal and which has only finitely many palindromic factors.

S. D. Huegelmeyer, S. Dreizler, P. H. Hauschildt, A. Seifahrt

We present a new code for the calculation of the 1D structure and synthetic spectra of accretion disks. The code is an extension of the general purpose stellar atmosphere code PHOENIX and is therefore capable of including extensive lists of atomic and molecular lines as well as dust in the calculations. We assume that the average viscosity can be represented

Daniel K. Wojcik, Szymon Leski

We propose two ways of estimating the current source density (CSD) from measurements of voltage on a Cartesian grid with missing recording points using the inverse CSD method. The simplest approach is to substitute local averages (LA) in place of missing data. A more elaborate alternative is to estimate a smaller number of CSD parameters than the actual numb

Shin I. Nishimura, Masahiro Ueda, Masaki Sasai

Eukaryotic cells can move spontaneously without being guided by external cues. For such spontaneous movements, a variety of different modes have been observed, including the amoeboid-like locomotion with protrusion of multiple pseudopods, the keratocyte-like locomotion with a widely spread lamellipodium, cell division with two daughter cells crawling in oppo

M. Paul, A. Mueller, A. Ruff, B. Schmid

Magnetite (Fe3O4) thin films on GaAs have been studied with HArd X-ray PhotoElectron Spectroscopy (HAXPES) and low-energy electron diffraction. Films prepared under different growth conditions are compared with respect to stoichiometry, oxidation, and chemical nature. Employing the considerably enhanced probing depth of HAXPES as compared to conventional x-r

Mattias Klintenberg, Sébastien Lebègue, Carlos Ortiz, Biplab Sanyal

We have studied theoretically, using density functional theory, several materials properties when going from one C layer in graphene to two and three g raphene layers and on to graphite. The properties we have focused on are the elastic constants, electronic structure (energy bands and density of state s), and the dielectric properties. For any of the proper

Antonio Avilés, Stevo Todorcevic

We provide two examples of complex homogeneous quadratic polynomials P on Banach spaces of the form l_1(I). The first polynomial P has both separable and nonseparable maximal zero subspaces. The second polynomial P has the property that while the index-set I is not countable, all zero subspaces of P are separable.

Jochen Bammert, Walter Zimmermann

We present theoretical results on the deterministic and stochastic motion of a dumbbell carried by a uniform flow through a three-dimensional spatially periodic potential. Depending on parameters like the flow velocity, there are two different kinds of movement: transport along a potential valley and stair-like motion oblique to the potential trenches. The c

Y. Kopelevich, B. Raquet, M. Goiran, W. Escoffier

Measurements of basal plane longitudinal rho_b(B) and Hall rho_H(B) resistivities were performed on highly oriented pyrolytic graphite (HOPG) samples in pulsed magnetic field up to B = 50 T applied perpendicular to graphene planes, and temperatures 1.5 K < T < 4.2 K. At B > 30 T and for all studied samples, we observed a sign change in rho_H(B) from electron

Krzysztof Kurdyka, Adam Parusinski

In this paper we show that the non-analyticity locus of an arc-analytic function is arc-symmetric. Recall that a function is called arc-analytic if it is real analytic on each real analytic arc. By a result of Bierstone and Milman a big class of arc-analytic function, namely those that satisfy a polynomial equation with real analytic coefficients, can be mad

T. Ghahramanyan, S. Mirzoyan, E. Poghosian, G. Yegorian

Kolmogorov&#39;s statistic is used for the analysis of properties of perturbations in the Cosmic Microwave Background signal. We obtain the maps of the Kolmogorov stochasticity parameter for W and V band temperature data of WMAP which are differently affected by the Galactic disk radiation and then we model datasets with various statistic of perturbations. T

Sabine Riemann, Andreas Schaelicke, Andriy Ushakov

The ILC baseline design for the positron source is based on a helical undulator and will deliver a positron beam with a polarization of 30% or more. In this contribution the need for fast reversal of the positron helicity is discussed.

R. Coziol, H. Andernach, C. A. Caretta, K. A. Alamo-Martinez

A large sample of Abell clusters of galaxies, selected for the likely presence of a dominant galaxy, is used to study the dynamical properties of brightest cluster members (BCMs). From visual inspection of Digitized Sky Survey images combined with redshift data we identify 1426 candidate BCMs in 1221 redshift components in 1169 different Abell clusters, the

Chengxiang Ding, Youjin Deng, Wenan Guo, Henk W. J. Blöte

We study a percolation problem based on critical loop configurations of the O($n$) loop model on the honeycomb lattice. We define dual clusters as groups of sites on the dual triangular lattice that are not separated by a loop, and investigate the the bond-percolation properties of these dual clusters. The universal properties at the percolation threshold ar

S. Sharma, S. Shallcross, J. K. Dewhurst, A. Sanna

Using state-of-the-art first-principles calculations we study the magnetic behaviour of CeOFeAs. We find the Ce layer moments oriented perpendicular to those of the Fe layers. An analysis of incommensurate magnetic structures reveals that the Ce-Ce magnetic coupling is rather weak with, however, a strong Fe-Ce coupling. Comparison of the origin of the tetrag

Z. M. Leinhardt, D. C. Richardson, G. Lufkin, J. Haseltine

In this paper we extend our numerical method for simulating terrestrial planet formation from Leinhardt and Richardson (2005) to include dynamical friction from the unresolved debris component. In the previous work we implemented a rubble pile planetesimal collision model into direct N-body simulations of terrestrial planet formation. The new collision model

Andy King

Logic programming is sometimes described as relational programming: a paradigm in which the programmer specifies and composes n-ary relations using systems of constraints. An advanced logic programming environment will provide tools that abstract these relations to transform, optimise, or even verify the correctness of a logic program. This talk will show th

A. N. Gerashchenko

We describe a method by which the abundance of metals and the reddening of globular clusters are simultaneously derived. The method is based on the analysis of the shape of the red giant branch and V magnitude of the horizontal branch on the V vs. (B-R) color-magnitude diagram for a cluster. The application of our technique to the photometry of the globular

R. Mazzarello, E. Tosatti

The magnetic ground state of nanosized systems such as Fe double chains, recently shown to form in the early stages of Fe deposition on Ir(100), is generally nontrivial. Using ab initio density functional theory we find that the straight ferromagnetic (FM) state typical of bulk Fe as well as of isolated Fe chains and double chains is disfavored after deposit

P. Chudzinski, M Gabay, T Giamarchi

We study the influence of non magnetic impurities on the phase diagram of doped two-leg Hubbard Cu-O ladders. In the absence of impurities this system posseses d-wave superconducting states and orbital current states depending on the doping. A single, strong, scatterer modifies its environment locally and this effect is assessed using a renormalization group

Nicolas Champagnat

In the course of Darwinian evolution of a population, punctualism is an important phenomenon whereby long periods of genetic stasis alternate with short periods of rapid evolutionary change. This paper provides a mathematical interpretation of punctualism as a sequence of change of basin of attraction for a diffusion model of the theory of adaptive dynamics.

Jin Zhang

W Comae has significant variability in multi-wavelengthes, from the radio to the gamma-ray bands. A bright outburst in the optical and X-ray bands was observed in 1998, and most recently, a strong TeV flare was detected by VERITAS in 2008. It is the first TeV intermediate-frequency-peaked BL Lacertae (IBL) source. I find that both the broadband spectral ener

Alexander Kobushkin, Yurij Kutafin

We analyzed contribution of quark degrees of freedom in the deuteron to the longitudinal, P_z&#39;, and transverse, P_x&#39;, polarizations of the proton in the d(\vec e,e&#39;\vec p)n break-up. It is demonstrated that such effects work in correct direction to explain experimental data. We predict that the polarizations should change qualitatively behavior a

F. Guglielmetti, R. Fischer, V. Dose

A probabilistic technique for the joint estimation of background and sources with the aim of detecting faint and extended celestial objects is described. Bayesian probability theory is applied to gain insight into the coexistence of background and sources through a probabilistic two-component mixture model, which provides consistent uncertainties of backgrou

E. W. Guenther, M. R. Zapatero Osorio, A. Mehner, E. L. Martin

Context: There is now growing evidence that some brown dwarfs (BDs) have very strong magnetic fields, and yet their surface temperatures are so low that the coupling is expected to be small between the matter and the magnetic field in the atmosphere. In the deeper layers, however, the coupling is expected to be much stronger. Aims: This raises the question o

Yi-Fang Chang

Based on the nonlinear equations of the density wave theory, the evolutionary direction and the observable conditions on spiral galaxies may be derived by the qualitative analysis theory.

Angel Ballesteros, Francisco J. Herranz

The superposition of the Kepler-Coulomb potential on the 3D Euclidean space with three centrifugal terms has recently been shown to be maximally superintegrable [Verrier P E and Evans N W 2008 J. Math. Phys. 49 022902] by finding an additional (hidden) integral of motion which is quartic in the momenta. In this paper we present the generalization of this res

Maria Bondani, Alessia Allevi, Alessandra Andreoni

We present the reconstruction of the Wigner function of some classical pulsed optical states obtained by direct measurement of the detected-photon probability distributions of the state displaced by a coherent field. We use a photodetector endowed with internal gain, which is operated in the non- photon-resolving regime. The measurements are performed up to

T. Jarlborg

Band calculations for the hole doped La$_2$CuO$_4$ system show that artificial periodicities of Ba dopants can give the material different properties than from a uniform distribution of dopants. A periodicity within the planes make static pseudogaps which could be tuned to raise the density-of-states (DOS) at $E_F$ and the superconducting $T_C$. A periodic d

Ji Jianghui, Liu Lin, H. Kinoshita, Li Guangyu

We perform numerical simulations to study the Habitable zones (HZs) and dynamical structure for Earth-mass planets in multiple planetary systems. For example, in the HD 69830 system, we extensively explore the planetary configuration of three Neptune-mass companions with one massive terrestrial planet residing in 0.07 AU $\leq a \leq$ 1.20 AU, to examine the

K. Ozdogan, E. Sasioglu, I. Galanakis

Employing first-principles calculations we study the structural, electronic and magnetic properties of the [Sc$_{1-x}$V$_x$]C and [Sc$_{1-x}$V$_x$]Si alloys. In their equilibrium rocksalt structure all alloys are non-magnetic. The zincblende and wurtzite structures are degenerated with respect to the total energy. For all concentrations the alloys in these l

Georg Hein

We study sheaves E on a smooth projective curve X which are minimal with respect to the property that $h^0(E \otimes L) >0$ for all line bundles L of degree zero. We show that these sheaves define ample divisors D(E) on the Picard torus Pic(X). Next we classify all minimal sheaves of rank one and two. As an application we show that the moduli space parameter

Omar Benhar, Davide Meloni

We analize the influence of nuclear effects on the determination of the nucleon axial mass from nuclear cross sections. Our work is based on a formalism widely applied to describe electron-nucleus scattering data in the impulse approximation regime. The results of numerical calculations show that correlation effects, not taken into account by the relativisti

J. K. Langley

The main result of the paper determines all real meromorphic functions of finite order in the plane for which the first derivative has finitely many zeros, while the function itself and one of its higher derivatives have finitely many non-real zeros.

M. L. Teague, A. P. Lai, J. Velasco, C. R. Hughes

Graphene has emerged as an electronic material that is promising for device applications and for studying two-dimensional electron gases with relativistic dispersion near two Dirac points. Nonetheless, deviations from Dirac-like spectroscopy have been widely reported with varying interpretations. Here we show evidence for strain-induced spatial modulations i

Vladimir M. Miklyukov, Vladimir G. Tkachev

We extend the well-known Denjoy-Ahlfors theorem on the number of different asymptotic tracts of holomorphic functions to subharmonic functions on arbitrary Riemannian manifolds. We obtain some new versions of the Liouville theorem for $\p$-harmonic functions without requiring the geodesic completeness requirement of a manifold. Moreover, an upper estimate of

K. Stanonik, E. Platen, M. A. Aragón-Calvo, J. H. van Gorkom

We have found an isolated polar disk galaxy in what appears to be a cosmological wall situated between two voids. This void galaxy is unique as its polar disk was discovered serendipitously in an HI survey of SDSS void galaxies, with no optical counterpart to the HI polar disk. Yet the HI mass in the disk is comparable to the stellar mass in the galaxy. This

Herbert H. B. Lau, Richard J. Stancliffe, Christopher A. Tout

We investigate the behaviour of asymptotic giant branch (AGB) stars between metallicities Z = 10-4 and Z = 10-8 . We determine which stars undergo an episode of flash-driven mixing, where protons are ingested into the intershell convection zone, as they enter the thermally pulsing AGB phase and which undergo third dredge-up. We find that flash-driven mixing

Deog Ki Hong

QCD predicts matter at high density should exhibit color superconductivity. We review briefly several pertinent properties of color superconductivity and then discuss how baryons are realized in color superconductors. Especially, we explain an attempt to describe the color-flavor locked quark matter in terms of bosonic degrees of freedom, where the gaped qua

A. V. Kuznetsov, N. V. Mikheev, A. A. Okrugin

The double conversion of the neutrino helicity $ν_L \to ν_R \to ν_L$ has been analyzed for supernova conditions, where the first stage is due to the interaction of the neutrino magnetic moment with plasma electrons and protons in the supernova core, and the second stage, due to the resonance spin flip of the neutrino in the magnetic field of the supernova en

George T. Fleming, Saul D. Cohen, Huey-Wen Lin, Victor Pereyra

We apply black-box methods, i.e. where the performance of the method does not depend upon initial guesses, to extract excited-state energies from Euclidean-time hadron correlation functions. In particular, we extend the widely used effective-mass method to incorporate multiple correlation functions and produce effective mass estimates for multiple excited st

Kang Ning, Hoong Kee Ng, Hon Wai Leong

For a set of mulitple sequences, their patterns,Longest Common Subsequences (LCS) and Shortest Common Supersequences (SCS) represent different aspects of these sequences profile, and they can all be used for biological sequence comparisons and analysis. Revealing the relationship between the patterns and LCS,SCS might provide us with a deeper view of the pat

Jianming Wen, Morton H. Rubin

In tripartite discrete systems, two classes of genuine tripartite entanglement have been discovered, namely, the Greenberger-Horne-Zeilinger (GHZ) class and the W class. To date, much research effort has been concentrated on the polarization entangled three-photon GHZ and W states. Most studies of continuous variable multiparticle entanglement have been focu

M. Donaire

In this paper we derive a general expression for the emission rate of an emitter which is placed at the center of a real cavity drilled in a generic random medium. We apply our formalism to the computation of the decay rate of a single atom which seats within a small molecule embedded in a continuous medium.

Agung Budiyono, Ken Umeno

Using the Madelung fluid picture of Schrödinger equation for a single free particle moving in one spatial dimension, we shall specify a class of wave functions whose quantum probability density is being trapped by the quantum potential it itself generates. The global convexity of the quantum potential generated by the initial self-trapped wave function will

A. Vikhlinin, S. W. Allen, M. Arnaud, M. Bautz

A moderate investment of observing time with the International X-ray Observatory to study high-redshift galaxy clusters detected in future large-scale surveys, will provide cosmological measurements of fundamental importance. IXO observations, combined with lensing follow-up, will measure the perturbation growth factor from z=0-2 with an accuracy comparable

Adilson E. Motter, Alberto Saa

The study of chaos in relativistic systems has been hampered by the observer dependence of Lyapunov exponents (LEs) and of conditions, such as orbit boundedness, invoked in the interpretation of LEs as indicators of chaos. Here we establish a general framework that overcomes both difficulties and apply the resulting approach to address three fundamental ques

P. A. Crowther, J. L. Bibby

Aims: We investigate the massive stellar content of the nearby dwarf irregular Wolf-Rayet galaxy IC 4662, and consider its global star forming properties in the context of other metal-poor galaxies, the SMC, IC 10 and NGC 1569. Methods: Very Large Telescope/FORS2 imaging and spectroscopy plus archival Hubble Space Telescope/ACS imaging datasets permit us to

Sang-Yong Lee, Antonio Ortega

We propose a new approach for image compression in digital cameras, where the goal is to achieve better quality at a given rate by using the characteristics of a Bayer color filter array. Most digital cameras produce color images by using a single CCD plate, so that each pixel in an image has only one color component and therefore an interpolation method is

Rolf Harren, Rob van Stee

We consider the problem of packing rectangles into bins that are unit squares, where the goal is to minimize the number of bins used. All rectangles have to be packed non-overlapping and orthogonal, i.e., axis-parallel. We present an algorithm for this problem with an absolute worst-case ratio of 2, which is optimal provided P != NP.

R. J. Siverd, B. S. Ryden, B. S. Gaudi

We identify, categorize, and quantify alignment effects among host and satellite galaxies using a spectroscopically-confirmed, low-redshift (z<0.23) galaxy sample from the Sloan Digital Sky Survey Data Release 6. Consistent with other recent findings, we find that satellite galaxies (SGs) of red, centrally concentrated (elliptical) host galaxies (HGs) with r

Dennis D. Dietrich

Characterising the propagation of particles in an external non-Abelian field only in terms of invariants constructed from its field tensor is not always sufficient, especially, in many analytically tractable and phenomenologically interesting cases.

Gavin Polhemus, Andrew J. S. Hamilton, Colin S. Wallace

Heating processes inside large black holes can produce tremendous amounts of entropy. Locality requires that this entropy adds on space-like surfaces, but the resulting entropy (10^10 times the Bekenstein-Hawking entropy in an example presented in the companion paper) exceeds the maximum entropy that can be accommodated by the black hole&#39;s degrees of fre

Michael Gronau, Jonathan L. Rosner

The availability of branching fractions for a large majority of $D_s$ decays permits the prediction of inclusive branching fractions. This is achieved with the help of a modest amount of input from an isospin statistical model applied to non-resonant multibody $D_s$ decays. A systematic uncertainty in these mostly small branching ratios is estimated by compa

L. Tian, K. Jacobs

Two-level system fluctuators (TLS&#39;s) in the tunnel barrier of a Josephson junction have recently been demonstrated to cause novel energy splittings in spectroscopic measurements of superconducting phase qubits. With their strong coupling to the Josephson junction and relatively long decoherence times, TLS&#39;s can be considered as potential qubits and d

Stephen Bruce Sontz

We prove identities involving the integral kernels of three versions (two being introduced here) of the Segal-Bargmann transform associated to a finite Coxeter group acting on a finite dimensional, real Euclidean space (the first version essentially having been introduced around the same time by Ben Saïd and Ørsted and independently by Soltani) and the Dunkl

B. L. James, Y. G. Tsamis, M. J. Barlow, M. S. Westmoquette

A study of the blue compact dwarf (BCD) galaxy Mrk 996 based on high resolution optical VLT VIMOS integral field unit spectroscopy is presented. Mrk 996 displays multi-component line emission, with most line profiles consisting of a narrow, central Gaussian with an underlying broad component. The broad HI Balmer component splits into two separate broad compo

Michael D. Seifert

Spontaneous Lorentz symmetry breaking can occur when the dynamics of a tensor field cause it to take on a non-zero expectation value in vacuo, thereby providing one or more &#34;preferred directions&#34; in spacetime. Couplings between such fields and spacetime curvature will then affect the dynamics of the metric, leading to interesting gravitational effect

Doron Kushnir, Eli Waxman

We show that the spectral and radial distribution of the nonthermal emission of massive, M>10^{14.5}M_sun, galaxy clusters (GCs) may be approximately described by simple analytic expressions, which depend on the GC thermal X-ray properties and on two model parameter, beta_{core} and eta_e. beta_{core} is the ratio of CR energy density (within a logarithmic C

Doron Kushnir, Boaz Katz, Eli Waxman

We argue that the observed correlation between the radio luminosity and the X-ray luminosity in radio emitting galaxy clusters implies that the radio emission is due to secondary electrons that are produced by p-p interactions and lose their energy by emitting synchrotron radiation in a strong magnetic field, B>(8πa T_{CMB}^4)^{1/2}\simeq 3\muG. We construct

Simone Mercuri

A possible topological interpretation of the Barbero-Immirzi parameter is proposed. Classically, by generalizing the Holst action to torsional spacetimes, we construct a precise analogy between the Barbero--Immirzi parameter and the $θ$-angle of Yang-Mills gauge theories, where the role of the Pontryagin class is played by a well known topological term conta

J. D. Rossi, E. V. Teixeira

We study the behavior of $p$-Dirichlet optimal design problem with volume constraint for $p$ large. As the limit as $p$ goes to infinity, we find a limiting free boundary problem governed by the infinity-Laplacian operator. We establish a necessary and sufficient condition for uniqueness of the limiting problem and, under such a condition, we determine preci

Federica Haupt, Tomas Novotny, Wolfgang Belzig

We investigate the effects of phonon scattering on the electronic current noise through nanojunctions using the non-equilibrium Green&#39;s functions formalism extended to include the counting field. In the case of weak electron-phonon coupling and a single broad electronic level we derive an analytic expression for the current noise at arbitrary temperature

Oleg Safronov

We study the distribution of eigenvalues of the one-dimensional Schrödinger operator with a complex valued potential $V$. We prove that if $|V|$ decays faster than the Coulomb potential, then the series of imaginary parts of square roots of eigenvalues is convergent.

Stephan Narison

We systematically re-examine the extraction of the masses and couplings of the 1^{-+} hybrid, four-quark and molecule mesons from QCD spectral sum rules (QSSR). To NLO for the perturbative and power corrections, the hybrid mass is M_H=1.81(6) GeV and M_H < 2.2(2) GeV from the positivity of the spectral function. In the same way, but to LO, the four-quark sta

N. T. Zinner, M. Thøgersen

We consider the stability of an ultracold trapped Bose-Einstein condensate near a Feshbach resonance. Using a modified Gross-Pitaevskii equation that includes higher-order terms and a multi-channel model of Feshbach resonances, we find regions where stability can be enhanced or suppressed around experimentally measured resonances. We suggest a number of ways

N. T. Zinner, K. Mølmer, C. Özen, D. J. Dean

We study a trapped system of fermions with a zero-range two-body interaction using the shell-model Monte Carlo method, providing {\em ab initio} results for the low particle number limit where mean-field theory is not applicable. We present results for the $N$-body energies as function of interaction strength, particle number, and temperature. The subtle que

Marta Volonteri, Priyamvada Natarajan

In this paper, we explore the establishment and evolution of the empirical correlation between black hole mass and velocity dispersion with redshift. We track the growth and accretion history of massive black holes starting from high redshift using two seeding models:(i) Population III remnants, and (ii) massive seeds from direct gas collapse. Although the s

Stephen D. H. Hsu, David Reeb

We investigate the experimental capabilities required to test whether black holes destroy information. We show that an experiment capable of illuminating the information puzzle must necessarily be able to detect or manipulate macroscopic superpositions (i.e., Everett branches). Hence, it could also address the fundamental question of decoherence versus wavef

L. Cywinski, W. M. Witzel, S. Das Sarma

We investigate decoherence due to pure dephasing of a localized spin qubit interacting with a nuclear spin bath. Although in the limit of a very large magnetic field the only decoherence mechanism is spectral diffusion due to dipolar flip-flops of nuclear spins, with decreasing field the hyperfine-mediated interactions between the nuclear spins become import

G. -Y. Qin, A. Majumder, H. Song, U. Heinz

Hard partons moving through a dense QCD medium lose energy by radiative emissions and elastic scatterings. Deposition of the radiative contribution into the medium requires rescattering of the radiated gluons. We compute the total energy loss and its deposition into the medium self-consistently within the same formalism, assuming perturbative interaction bet

C. Martin, M. E. Tillman, H. Kim, M. A. Tanatar

The superconducting penetration depth, $λ(T)$, has been measured in RFeAsO$_{0.9}$F$_{0.1}$ (R=La,Nd) single crystals (R-1111). In Nd-1111, we find an upturn in $λ(T)$ upon cooling and attribute it to the paramagnetism of the Nd ions, similar to the case of the electron-doped cuprate Nd-Ce-Cu-O. After the correction for paramagnetism, the London penetration