May 2009 arXiv papers — page 6

Tim Namsoo

The ZEUS and H1 collaborations have made the first direct measurements of the longitudinal proton structure function, FL, which is strongly correlated to the gluon density in the proton. The ZEUS collaboration have also extracted the structure function, F2, which, for the first time, has been done so at high y without any assumptions about FL.

Sara Biagini, Marco Frittelli, Matheus R. Grasselli

For utility functions $u$ finite valued on $\mathbb{R}$, we prove a duality formula for utility maximization with random endowment in general semimartingale incomplete markets. The main novelty of the paper is that possibly non locally bounded semimartingale price processes are allowed. Following Biagini and Frittelli \cite{BiaFri06}, the analysis is based o

Zhiheng Li, Li Li, Yudong Chen, Yi Zhang

In this Letter, we show that under the assumption of high resolution, the quantization errors of fGn and fBm signals with uniform quantizer can be treated as uncorrelated white noises.

F. Mayet, O. Guillaudin, C. Grignon, C. Koumeir

The MIMAC project is a multi-chamber detector for Dark Matter search, aiming at measuring both track and ionization with a matrix of micromegas micro-TPC filled with He3 and CF4. Recent experimental results on the first measurements of the Helium quenching factor at low energy (1 keV recoil) are presented, together with the first simulation of the track reco

Peter G. Steeneken, Jiri Stulemeijer

Non-linearities play an important role in micro- and nano- electromechanical system (MEMS and NEMS) design. In common electrostatic and magnetic actuators, the forces and voltages can depend in a non-linear way on position, charge, current and magnetic flux. Mechanical spring structures can cause additional non-linearities via material, geometrical and conta

J. P. Coe, I. D'Amico

We calculate the `exact' potential corresponding to a one-dimensional interacting system of two electrons with a specific, tailored density. We use one-dimensional density-functional theory with a local-density approximation (LDA) on the same system and calculate densities and energies, which are compared with the `exact' ones. The `interacting-LDA s

Leo Creedon, Joe Gildea

The structure of the unitary unit group of the group algebra ${\F}_{2^k} Q_{8}$ is described as a Hamiltonian group.

Sheldon Goldstein, Daniel V. Tausk, Roderich Tumulka, Nino Zanghi

Conway and Kochen have presented a "free will theorem" (Notices of the AMS 56, pgs. 226-232 (2009)) which they claim shows that "if indeed we humans have free will, then [so do] elementary particles." In a more precise fashion, they claim it shows that for certain quantum experiments in which the experimenters can choose between several optio

A. Principi, Marco Polini, G. Vignale

A two-dimensional gas of massless Dirac fermions (MDFs) is a very useful model to describe low-energy electrons in monolayer graphene. Because the MDF current operator is directly proportional to the (sublattice) pseudospin operator, the MDF current-current response function, which describes the response to a vector potential, happens to coincide with the ps

Philip Phillips, Ting-Pong Choy, Robert G. Leigh

The standard theory of metals, Fermi liquid theory, hinges on the key assumption that although the electrons interact, the low-energy excitation spectrum stands in a one-to-one correspondence with that of a non-interacting system. In the normal state of the copper-oxide high-temperature superconductors, drastic deviations from the Fermi liquid picture obtain

J. S. Lawrence, M. C. B. Ashley, J. Bailey, D. Barrado y Navascues

PILOT (the Pathfinder for an International Large Optical Telescope is a proposed 2.5 m optical/infrared telescope to be located at DomeC on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These c

Dietrich Notbohm

Homology decomposition techniques are a powerful tool used in the analysis of the homotopy theory of (classifying) spaces. The associated Bousfield-Kan spectral sequences involve higher derived limits of the inverse limit functor. We study the impact of depth conditions on the vanishing of these higher limits and apply our theory in several cases. We will sh

E. Hernandez Zapata, L. Martinez Balbuena, I Santamaria-Holek

We propose a free energy expression accounting for the formation of spherical vesicles from planar lipidic membranes and derive a Fokker-Planck equation for the probability distribution describing the dynamics of vesicle formation. We found that formation may occur as an activated process for small membranes and as a transport process for sufficiently large

Stefano Bellucci, Sergey Krivonos

Proceeding from nonlinear realizations of (super)conformal symmetries, we explicitly demonstrate that adding the harmonic oscillator potential to the action of conformal mechanics does not break these symmetries but modifies the transformation properties of the (super)fields. We also analyze the possibility to introduce potentials in N=4 supersymmetric mecha

Hans C. Fogedby, Alberto Imparato

We consider the 1D motion of an overdamped Brownian particle in a general potential in the low temperature limit. We derive an explicit expression for the probability distribution for the heat transferred to the particle. We find that the local minima in the potential yield divergent side bands in the heat distribution in addition to the divergent central pe

Adrian Signer

This article is a very basic introduction to supersymmetry. It introduces the two kinds of superfields needed for supersymmetric extensions of the Standard Model, the chiral superfield and the vector superfield, and discusses in detail how to construct supersymmetric, gauge invariant Lagrangians. The main ideas on how to break supersymmetry spontaneously are

Paul Sjoberg, Otto G Berg, Johan Elf

The reaction-diffusion master equation (RDME) is commonly used to model processes where both the spatial and stochastic nature of chemical reactions need to be considered. We show that the RDME in many cases is inconsistent with a microscopic description of diffusion limited chemical reactions and that this will result in unphysical results. We describe how

V. A. Benderskii, E. I. Kats

We investigate the time evolution process of one selected (initially prepared by optical pumping) vibrational molecular state, coupled to all other intra-molecular vibrational states of the same molecule, and also to its environment. Molecular states forming the first reservoir are characterised by a discrete dense spectrum, whereas the environment reservoir

A. Pashkin, M. Dressel, S. G. Ebbinghaus, M. Hanfland

The crystal structures of the quasi-one-dimensional organic salts (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$ were studied by pressure-dependent x-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a structural phase transition at 8.5 and 5.5 GPa for (TMTTF)$_2$PF$_6$ and (TMTSF)$_2$PF$_6$, respectively.

N. M. H. Vaytet, A. P. Rushton, M. Lloyd, J. A. López

We present a detailed kinematical analysis of the young compact hourglass-shaped planetary nebula Hb 12. We performed optical imaging and longslit spectroscopy of Hb 12 using the Manchester echelle spectrometer with the 2.1m San Pedro Martir telescope. We reveal, for the first time, the presence of end caps (or knots) aligned with the bipolar lobes of the pl

Ramkrishna Das, Dipankar P. K. Banerjee, N. M. Ashok

We present near-infrared (1 - 2.5 micron) spectroscopic and photometric results of Nova V2615 Ophiuchi which was discovered in outburst in 2007 March. Our observations span a period of ~ 80 days starting from 2007 March 28 when the nova was at its maximum light. The evolution of the spectra are shown from the initial P-Cygni phase to an emission-line phase a

Danilo Piparo, Gregory Schott, Gunter Quast

RooStatsCms is an object oriented statistical framework based on the RooFit technology. Its scope is to allow the modelling, statistical analysis and combination of multiple search channels for new phenomena in High Energy Physics. It provides a variety of methods described in literature implemented as classes, whose design is oriented to the execution of mu

L. I. Danilov

The absolute continuity of the spectrum for the periodic Dirac operator $$ \hat D=\sum_{j=1}^n(-i\frac {\partial}{\partial x_j}-A_j)\hat α_j + \hat V^{(0)}+\hat V^{(1)}, x\in R^n, n\geq 3, $$ is proved given that either $A\in C(R^n;R^n)\cap H^q_{loc}(R^n;R^n)$, 2q > n-2, or the Fourier series of the vector potential $A:R^n\to R^n$ is absolutely convergent. H

Carlo Giunti

The claims that the GSI time anomaly is due to the mixing of neutrinos in the final state of the observed electron-capture decays of hydrogen-like heavy ions are refuted with the help of an analogy with a double-slit experiment. It is a consequence of causality. It is shown that the GSI time anomaly may be caused by quantum beats due to the existence of two

Steven D. Bass

The proton spin puzzle has challenged our understanding of QCD for the last 20 years. New measurements of polarized glue, valence and sea quark polarization, including strange quark polarization, are available. What is new and exciting in the data, and what might this tell us about the structure of the proton ? The proton spin puzzle seems to be telling us a

J. S. Lawrence, M. C. B. Ashley, A. Bunker, R. Bouwens

PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5 m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These

Bernardo N. B. de Lima, Remy Sanchis, Roger W. C. Silva

Consider an independent site percolation model on $\Z^d$, with parameter $p \in (0,1)$, where all long range connections in the axes directions are allowed. In this work we show that given any parameter $p$, there exists and integer $K(p)$ such that all binary sequences (words) $ξ\in \{0,1\}^{\N}$ can be seen simultaneously, almost surely, even if all connec

Daniela Ilea

This application comes to help software architects and developers during the long process between user's stories, designing the application's structure and actually coding it.

Ioana Iacob

The present study aims to evaluate the efficiency of the computer assisted English classes and to emphasize the necessity of developing sound methodological strategies adjusted to the new technology. It also present the benefits of using the computer in the pre-school and elementary school classes, highlighted by a report on the comparative observation of fo

Alexandra-Emilia Fortis

This paper synthesizes the actions performed in order to transform a classic scientific research journal - 'Annals. Computer Science Series' - available only in printed form until 2008, into a modern e-journal with free access to the full text of the articles. For achieving this goal, the research papers have been included in various article database

Georgiana-Petruta Fintineanu, Florentina Anica Pintea

The present article aims to describe a project consisting in designing a framework of applications used to create graphical interfaces with an Oracle distributed database. The development of the project supposed the use of the latest technologies: database Oracle server, Tomcat web server, JDBC (Java library used for accessing a database), JSP and Tag Librar

Ovidiu Crista

The goal of the presented work is to illustrate a method by which the data exchange between a standalone computer software and a shared database server can be protected of unauthorized interceptation of the traffic in Internet network, a transport network for data managed by those two systems, interceptation by which an attacker could gain illegetimate acces

Adrian Cojocariu, Cristina Ofelia Stanciu

The learning and assessment activities have undergone major changes due to the development of modern technologies. The computer-assisted learning and testing has proven a number of advantages in the development of modern educational system. The paper suggests a solution for the computer-assisted testing, which uses XML technologies, a solution that could mak

A. R. Muratov, E. I. Kats, H. Schober

We propose a simple phenomenological model describing vibrational dynamics in a class of materials (like clathrates), which are crystalline compounds with closed cavities in their structures. In the spirit of a minimalist approach, our model includes only the minimum of ingredients necessary to capture the generic features of this class of compounds as broug

Alexandru Cicortas, Victoria Stana Iordan, Alexandra Emilia Fortis

The paper proposes an analysis on some existent ontologies, in order to point out ways to resolve semantic heterogeneity in information systems. Authors are highlighting the tasks in a Knowledge Acquisiton System and identifying aspects related to the addition of new information to an intelligent system. A solution is proposed, as a combination of ontology r

Peter Grassl, Hong S. Wong, Nick R. Buenfeld

In this paper, the influence of aggregate size and volume fraction on shrinkage induced micro-cracking and permeability of concrete and mortar was investigated. Nonlinear finite element analyses of model concrete and mortar specimens were performed. The aggregate diameter was varied between 2 and 16 mm. Furthermore, a range of volume fractions between 0.1 an

Claudiu Chirilov

This work wishes to support various mathematical issues concerning the iterative methods with the help of new programming languages. We consider a way to show how problems in math have an answer by using different academic resources and different thoughts. Here we treat methods like Gauss-Seidel's, Cramer's and Gauss-Jordan's.

Dominique Duval, Jean-Claude Reynaud

This paper presents a unified framework for dealing with a deduction system and a denotational semantics of exceptions. It is based on the fact that handling exceptions can be seen as a kind of generalized case distinction. This point of view on exceptions has been introduced in 2004, it is based on the notion of diagrammatic logic, which assumes some famili

T. Rausmann, A. Khoukaz, M. Buescher, D. Chiladze

The differential and total cross sections for the d+p->3He+eta reaction have been measured at COSY-ANKE at excess energies of 19.5, 39.4, and 59.4 MeV over the full angular range. The results are in line with trends apparent from the detailed near-threshold studies and also agree with those from CELSIUS, though the present data have higher precision. While a

Reinhard Alkofer, Axel Maas, Daniel Zwanziger

The non-perturbative domain of QCD contains confinement, chiral symmetry breaking, and the bound state spectrum. For the calculation of the latter, the Coulomb gauge is particularly well-suited. Access to these non-perturbative properties should be possible by means of the Green's functions. However, Coulomb gauge is also very involved, and thus hard to

Koji Ishiwata, Shigeki Matsumoto, Takeo Moroi

Motivated by the PAMELA anomaly in the fluxes of cosmic-ray electron and positron, we study the cosmic gamma-ray induced by the inverse Compton (IC) scattering process in unstable dark matter scenario assuming that the anomaly is due to the electron and positron emission by the decay of dark matter. We calculate the fluxes of IC-induced gamma-ray produced in

Omar Sakka, Valerie Botta-Genoulaz, Lorraine Trilling

Improvement of industrial performance such as cost, lead-time, adaptability, variety and traceability is the major finality of companies. At this need corresponds the necessity to collaborate and to strengthen their coordination mechanisms. Information exchange becomes then a strategic question: what is the nature of the information that can be shared with c

T. Westerkamp, M. Deppe, R. Kuechler, M. Brando

We report on a comprehensive study of CePd$_{1-x}$Rh$_x$ $(0.6 \leq x \leq 0.95)$ poly- and single crystals close to the ferromagnetic instability by means of low-temperature ac susceptibility, magnetization and volume thermal expansion. The signature of ferromagnetism in this heavy-fermion system can be traced from 6.6 K in CePd down to 25 mK for $x=0.87$.

Roberto Emparan, Giuseppe Milanesi

We present an exact solution for a black hole localized near an infrared wall in four-dimensional anti-deSitter space. By computing the holographic stress tensor we show that the CFT dual of the black hole is a 2+1-dimensional ball (i.e., a disk) of plasma at finite temperature, surrounded by vacuum. This confirms some earlier conjectures about plasma balls

Bao-Tian Wang, Ping Zhang, Hongliang Shi, Bo Sun

The crystal structure, mechanical properties and electronic structure of ground state BeH$_{2}$ are calculated employing the first-principles methods based on the density functional theory. Our calculated structural parameters at equilibrium volume are well consistent with experimental results. Elastic constants, which well obey the mechanical stability crit

Cor Kraaikamp, Thomas A. Schmidt, Ionica Smeets

We give natural extensions for the alpha-Rosen continued fractions of Dajani et al. for a set of small alpha values by appropriately adding and deleting rectangles from the region of the natural extension for the standard Rosen fractions. It follows that the underlying maps have equal entropy.

Maciej Błaszak, Metin Gürses, Kostyantyn Zheltukhin

Bi-presymplectic chains of one-forms of co-rank one are considered. The conditions in which such chains represent some Liouville integrable systems and the conditions in which there exist related bi-Hamiltonian chains of vector fields are derived. To present the construction of bi-presymplectic chains, the notion of dual Poisson-presymplectic pair is used an

Marco Billo', Livia Ferro, Marialuisa Frau, Laurent Gallot

We compute the partition function for the exotic instanton system corresponding to D-instantons on D7 branes in Type I' theory. We exploit the BRST structure of the moduli action and its deformation by RR background to fully localize the integration. The resulting prepotential describes non-perturbative corrections to the quartic couplings of the gauge f

M. de Leon, D. Martin de Diego, M. Salgado, S. Vilariño

In this paper we introduce a geometric description of Lagrangian and Hamiltonian classical field theories on Lie algebroids in the framework of k-symplectic geometry. We discuss the relation between Lagrangian and Hamiltonian descriptions through a convenient notion of Legendre transformation. The theory is a natural generalization of the standard one; in ad

H. P. Specht, J. Bochmann, M. Muecke, B. Weber

While the phase of a coherent light field can be precisely known, the phase of the individual photons that create this field, considered individually, cannot. Phase changes within single-photon wave packets, however, have observable effects. In fact, actively controlling the phase of individual photons has been identified as a powerful resource for quantum c

Jan Novak, Chris J. Pearce, Peter Grassl, Liu Yang

Microbond tests composed of single fibre and matrix droplet are often used to determine the properties of fibre reinforced composites. Interfacial shear strength is quantified by the maximum pull-out force assuming a uniform stress distribution along the fibre. Here, nonlinear finite element analyses are performed to investigate the validity of this assumpti

Piotr Bania

Nowadays most of the malware applications are either packed or protected. This techniques are applied especially to evade signature based detectors and also to complicate the job of reverse engineers or security analysts. The time one must spend on unpacking or decrypting malware layers is often very long and in fact remains the most complicated task in the

Patricia Sanchez-Blazquez, Stephanie Courty, Brad Gibson, Christopher Brook

We analyse a high-resolution, fully cosmological, hydrodynamical disc galaxy simulation, to study the source of the double-exponential light profiles seen in many stellar discs, and the effects of stellar radial migration upon the spatio-temporal evolution of both the disc age and metallicity distributions. We find a "break" in the pure exponential s

Christian Borghesi

The previous twelve turnout rates of French national elections by municipality show regularities. These regularities do not depend on the national turnout level, nor on the nature of the election. Based on past statistical regularities we make three predictions. The first one deals with the standard deviation of the turnout rate by municipality. The second o

David Viennot, Jean-Marie Vigoureux

In a recent paper (Vigoureux et al. Int. J. Theor. Phys. 47:928, 2007) it has been suggested that the velocity of light and the expansion of the universe are two aspects of one single concept connecting space and time in the expanding universe. It has then be shown that solving Friedmann's equations with that interpretation (and keeping c = constant) can

C. Brinch, J. K. Jørgensen, M. R. Hogerheijde

Low-mass star formation is described by gravitational collapse of dense cores of gas and dust. At some point during the collapse, a disk is formed around the protostar and the disk will spin up and grow in size as the core contracts because of angular momentum conservation. The question is how early the disk formation process occurs. In this paper we aim to

Markus Brodmann, Peter Schenzel

We first show that the union of a projective curve with one of its extremal secant lines satisfies the linear general position principle for hyperplane sections. We use this to give an improved approximation of the Betti numbers of curves ${\mathcal C} \subset \mathbb P^r_K$ of maximal regularity with $°{\mathcal C} \leq 2r -3.$ In particular we specify the

M. Gillon, B. -O. Demory, A. H. M. J. Triaud, T. Barman

We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and

Elmar Bittner, Andreas Nußbaumer, Wolfhard Janke

We determine the interface tension for the 100, 110 and 111 interface of the simple cubic Ising model with nearest-neighbour interaction using novel simulation methods. To overcome the droplet/strip transition and the droplet nucleation barrier we use a newly developed combination of the multimagnetic algorithm with the parallel tempering method. We investig

Ugo Dal Lago, Andrea Masini, Margherita Zorzi

A strong confluence result for Q*, a quantum lambda-calculus with measurements, is proved. More precisely, confluence is shown to hold both for finite and infinite computations. The technique used in the confluence proof is syntactical but innovative. This makes Q* different from similar quantum lambda calculi, which are either measurement-free or provided w

Carlo Nipoti

There are two families of luminous elliptical galaxies: cusp galaxies, with steep central surface-brightness profiles, and core galaxies, whose surface-brightness profiles have flat central cores. Thermal evaporation of accreted cold gas by the hot interstellar medium may be at the origin of this cusp-core dichotomy: in less massive (hot-gas poor) galaxies c

Lorenzo Franceschini

This paper is an extended and more detailed version of arXiv:0812.0533. We tackle the problem of constructing explicit examples of topological cocycles of Roberts' net cohomology, as defined abstractly by Brunetti and Ruzzi. We consider the simple case of massive bosonic quantum field theory on the two dimensional Einstein cylinder. After deriving some c

Junya Shibata, Hiroshi Kohno

We theoretically examine the spin-transfer torque in the presence of spin-orbit interaction (SOI) at impurities in a ferromagnetic metal on the basis of linear response theory. We obtained, in addition to the usual spin-transfer torque, a new contributioin $\sim {\bm j}_{\rm SH}^{\phantom{\dagger}} \cdot \nabla {\bm n}$ in the first order in SOI, where ${\bm

Eugene Kazantsev

Variational data assimilation technique applied to identification of optimal approximations of derivatives near boundary is discussed in frames of one-dimensional wave equation. Simplicity of the equation and of its numerical scheme allows us to discuss in detail as the development of the adjoint model and assimilation results. It is shown what kind of error

Stéphane Simon

We compute (algebraically) the Euler characteristic of a complex of sheaves with constructible cohomology. A stratified Poincaré-Hopf formula is then a consequence of the smooth Poincaré-Hopf theorem and of additivity of the Euler-Poincaré characteristic with compact supports, once we have a suitable definition of index.

LAT Collaboration, A. A. Abdo, G. Ghisellini, L. Maraschi

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope of high-energy gamma-ray emission from the peculiar quasar PMN J0948+0022 (z=0.5846). The optical spectrum of this object exhibits rather narrow Hbeta (FWHM(Hbeta) ~ 1500 km s^-1), weak forbidden lines and is therefore classified as a narrow-line type I quas

Iris Reichenbach, Paul S. Julienne, Ivan H. Deutsch

Nuclear spin exchange occurs in ultracold collisions of fermionic alkaline-earth-like atoms due to a difference between s- and p-wave phase shifts. We study the use of an optical Feshbach resonance, excited on the ${}^1S_0 \to {}^3P_1$ intercombination line of ${}^{171}$Yb, to affect a large modification of the s-wave scattering phase shift, and thereby opti

Lixin Xu, Wenbo Li, Jianbo Lu

In this paper, linear first order expansion of deceleration parameter $q(z)=q_0+q_1(1-a)$ ($M_1$), constant jerk $j=j_0$ ($M_2$) and third order expansion of luminosity distance ($M_3$) are confronted with cosmic observations: SCP 307 SN Ia, BAO and observational Hubble data (OHD). Likelihood is implemented to find the best fit model parameters. All these mo

Mikio Eto, Tomohiro Yokoyama

We theoretically investigate an extrinsic spin Hall effect (SHE) in semiconductor heterostructures due to the scattering by an artificial potential created by antidot, STM tip, etc. The potential is electrically tunable. First, we formulate the SHE in terms of phase shifts in the partial wave expansion for two-dimensional electron gas. The effect is signific

Hua Jiang, Lei Wang, Qing-feng Sun, X. C. Xie

We study the disorder effect on the transport properties in the HgTe/CdTe semiconductor quantum wells. We confirm that at a moderate disorder strength, the initially un-quantized two terminal conductance becomes quantized, and the system makes a transition to the novel topological Anderson insulator (TAI). Conductances calculated for the stripe and cylinder

Jie Liu, Juntao Song, Qing-feng Sun, X. C. Xie

The heat generation by an electric current flowing through a quantum dot with the dot containing both electron-electron interaction and electron-phonon interaction, is studied. Using the non-equilibrium Keldysh Green's function method, the current-induced heat generation is obtained. We find that for a small phonon frequency, heat generation is proportio

Huai-Bin Zhuang, Qing-feng Sun, X. C. Xie

The Kondo effect in the system consisting of a magnetic adatom on the graphene is studied. By using the non-equilibrium Green function method with the slave-boson mean field approximation, the local density of state (LDOS) and the conductance are calculated. For a doped graphene, the Kondo phase is present at all time. Surprisingly, two kinds of Kondo regime

Kaca Bradonjic

One of the deepest insights from the general theory of relativity is the relational nature of spacetime. While it is a generally agreed on that the nature of spacetime must be drastically different at the Planck scale, it has been a common practice to assume a full pseudo-Riemannian geometry of spacetime no matter what the physical fields present are, and to

Carlos E. Chavez

In this article we explore the aspect of the F ring with respect to the anti-alignment configuration between the ring and Prometheus. We focus our attention on the shape of the F ring's azimuthal channels which were first reported by Porco et al. (2005) and numerically explored by Murray et al. (2005), who found excellent agreement between Cassini's

Alexandre Graell i Amat, Raphael Le Bidan

In this letter we consider the ensemble of codes formed by the serial concatenation of a Hamming code and two accumulate codes. We show that this ensemble is asymptotically good, in the sense that most codes in the ensemble have minimum distance growing linearly with the block length. Thus, the resulting codes achieve high minimum distances with high probabi

Frederic Bihan, Frank Sottile

We give a bound for the number of real solutions to systems of n polynomials in n variables, where the monomials appearing in different polynomials are distinct. This bound is smaller than the fewnomial bound if this structure of the polynomials is not taken into account.

N. Nardetto, W. Gieren, P. Kervella, P. Fouque

The cross correlation method (hereafter CC) is widely used to derive the radial velocity curve of Cepheids when the signal to noise of the spectra is low. However, if it is used with the wrong projection factor, it might introduce some biases in the Baade-Wesselink (hereafter BW) methods of determining the distance of Cepheids. In addition, it might affect t

Silke Weinfurtner, Angela White, Matt Visser

We investigate the behaviour of quantum fields coupled to a spacetime geometry exhibiting finite regions of Euclidean (Riemannian) signature. Although from a gravity perspective this situation might seem somewhat far fetched, we will demonstrate its direct physical relevance for an explicitly realizable condensed matter system whose linearized perturbations

E. Faber, D. B. Westra

We study blowups of affine n-space with center an arbitrary monomial ideal and call monomial ideals that render smooth blowups tame ideals. We give a combinatorial criterion to decide whether the blowup is smooth and apply this criterion to discuss a smoothing procedure proposed by Rosenberg, monomial building sets and permutohedra.

Sung-Sik Lee

We study the low energy effective theory for a non-Fermi liquid state in 2+1 dimensions, where a transverse U(1) gauge field is coupled with a patch of Fermi surface with N flavors of fermion in the large N limit. In the low energy limit, quantum corrections are classified according to the genus of the 2d surface on which Feynman diagrams can be drawn withou

Andrew Randono, David Sloan

In this paper we investigate the manner in which the internal spin angular momentum of a spinor field is encoded in the gravitational field at asymptotic infinity. The inclusion of internal spin requires us to re-analyze our notion of asymptotic flatness. In particular, the Poincaré symmetry at asymptotic infinity must replaced by a spin-enlarged Poincaré sy

David V. Stark, Stacy. S. McGaugh, Robert. A. Swaters

We calibrate the Baryonic Tully-Fisher (BTF) Relation using a sample of gas dominated galaxies. These determine the absolute scale of the baryonic mass--rotation speed relation independent of the choice of stellar mass estimator. We find a BTF slope of 3.94 +/- 0.07 (random) +/- 0.08 (systematic) and a zero point of 1.79 +/- 0.26 (random) +/- 0.25 (systemati

Denis Gaidashev, Tomas Johnson

It is known that the famous Feigenbaum-Coullet-Tresser period doubling universality has a counterpart for area-preserving maps of ${\fR}^2$. A renormalization approach has been used in \cite{EKW1} and \cite{EKW2} in a computer-assisted proof of existence of a "universal" area-preserving map $F_*$ -- a map with orbits of all binary periods $2^k, k \in

D. S. L. Abergel, Tapash Chakraborty

We propose a device for the generation of valley polarized electronic current in bilayer graphene. By analyzing the response of this material to intense terahertz frequency light in the presence of a transverse electric field, we demonstrate that dynamical states are induced in the gapped energy region, and if the system parameters are properly tuned, these

M. Stopa, J. J. Krich, A. Yacoby

We discuss a feedback mechanism between electronic states in a double quantum dot and the underlying nuclear spin bath. We analyze two pumping cycles for which this feedback provides a force for the Overhauser fields of the two dots to either equilibrate or diverge. Which of these effects is favored depends on the g-factor and Overhauser coupling constant A

Alessia Gualandris, David Merritt

We study the short- and long-term effects of an intermediate mass black hole (IMBH) on the orbits of stars bound to the supermassive black hole (SMBH) at the center of the Milky Way. A regularized N-body code including post-Newtonian terms is used to carry out direct integrations of 19 stars in the S-star cluster for 10 Myr. The mass of the IMBH is assigned

Brian Yanny, Heidi Jo Newberg, Jennifer A. Johnson, Young Sun Lee

We show that the Sagittarius dwarf tidal stream can be traced with very red K/M-giant stars selected from SDSS photometry. A subset of these stars are spectroscopically confirmed with SEGUE and SDSS spectra, and the distance scale of 2MASS and SDSS M giants is calibrated to the RR Lyrae distance scale. The absolute g band magnitude of the K/M-giant stars at

Efton Park

Suppose that $ϕ$ and $ψ$ are smooth complex-valued functions on the circle that are invertible, have winding number zero with respect to the origin, and have meromorphic extensions to an open neighborhood of the closed unit disk. Let $T_ϕ$ and $T_ψ$ denote the Toeplitz operators with symbols $ϕ$ and $ψ$ respectively. We give an explicit formula for the deter

Michele Trenti, Michael Shull

Cosmological simulations of Population III star formation suggest an initial mass function (IMF) biased toward very massive stars (M>100Msun) formed in minihalos at redshift z>20, when the cooling is driven by molecular hydrogen. However, this result conflicts with observations of extremely-metal poor (EMP) stars in the Milky Way halo, whose r-process elemen

Michał J. Michałowski, Jens Hjorth, Darach Watson

The nature of galaxies selected at submillimeter wavelengths (SMGs, S_850 > 3 mJy), some of the bolometrically most luminous objects at high redshifts, is still elusive. In particular their star formation histories and source of emission are not accurately constrained. In this paper we introduce a new approach to analyse the SMG data. Namely, we present the

Michele Trenti, Massimo Stiavelli, Michael Shull

While the average metallicity of the intergalactic medium rises above Z~10^{-3} Zsun by the end of the reionization, pockets of metal-free gas can still exist at later times. We quantify the presence of a long tail in the formation rate of metal-free halos during late stages of reionization (redshift z~6), which might offer the best window to detect Populati

Tamara Bogdanovic, Christopher S. Reynolds, Steven A. Balbus, Ian J. Parrish

We perform a suite of simulations of cooling cores in clusters of galaxies in order to investigate the effect of the recently discovered heat flux buoyancy instability (HBI) on the evolution of cores. Our models follow the 3-dimensional magnetohydrodynamics (MHD) of cooling cluster cores and capture the effects of anisotropic heat conduction along the lines

Pawel Sobkowicz

There are numerous examples of societies with extremely stable mix of contrasting opinions. We argue that this stability is a result of an interplay between society network topology adjustment and opinion changing processes. To support this position we present a computer model of opinion formation based on some novel assumptions, designed to bring the model

Yuri Kornyushin

It is shown that hydrogen atom is a unique object in physics having negative energy of electric field, which is present in the atom. This refers also to some hydrogen-type atoms: hydrogen anti-atom, atom composed of proton and antiproton, and positronium.

Jessica Striker

Alternating sign matrices (ASMs) are square matrices with entries 0, 1, or -1 whose rows and columns sum to 1 and whose nonzero entries alternate in sign. We put ASMs into a larger context by studying the order ideals of subposets of a certain poset, proving that they are in bijection with a variety of interesting combinatorial objects, including ASMs, total

Claus Horn

This paper proposes a new way to do event generation and analysis in searches for new physics at the LHC. An abstract notation is used to describe the new particles on a level which better corresponds to detector resolution of LHC experiments. In this way the SUSY discovery space can be decomposed into a small number of eigenmodes each with only a few parame

Massimo Ostilli

We prove that lattice quantum systems may undergo a first-order quantum phase transition through a general mechanism which consists in an infinite dilution of the states associated to (or, more in general, near to) the lowest energy levels. The equation giving the critical point is derived and discussed at several degrees of generalizations: given an infinit

Andrzej Herdegen

We propose a parallel introduction to Galilean and Einsteinian relativity based on the causal structure and inertial motions. Galilean and Poincare transformations, as objects secondary to the geometrical structure, are left aside.

Tomasz S. Mrowka, Daniel Ruberman, Nikolai Saveliev

We introduce a gauge-theoretic integer lift of the Rohlin invariant of a smooth 4-manifold X with the homology of $S^1 \times S^3$. The invariant has two terms; one is a count of solutions to the Seiberg-Witten equations on X, and the other is essentially the index of the Dirac operator on a non-compact manifold with end modeled on the infinite cyclic cover

Mu-in Park

Recently Horava proposed a renormalizable gravity theory in four dimensions which reduces to Einstein gravity with a non-vanishing cosmological constant in IR but with improved UV behaviors. Here, I study an IR modification which breaks "softly" the detailed balance condition in Horava model and allows the asymptotically flat limit as well. I obtain