October 2008 arXiv papers — page 31

P. Saracco, M. Longhetti, S. Andreon

[Abridged]We present the morphological analysis based on HST-NICMOS observations in the F160W filter of a sample of 32 early-type galaxies (ETGs) at 1<z<2 with spectroscopic confirmation of their redshift and spectral type. We find that ETGs at are composed of two distinct populations, an older population (oETGs) and a younger population (yETGs) whose mean a

Taysun Kimm, Rachel S. Somerville, Sukyoung K. Yi, Frank C. van den Bosch

We investigate the correlation of star formation quenching with internal galaxy properties and large scale environment (halo mass) in empirical data and theoretical models. We make use of the halo-based Group Catalog of Yang and collaborators, which is based on the Sloan Digital Sky Survey. Data from the Galaxy Evolution Explorer (GALEX) are also used to ext

Thomas R. Junk

The latest measurements of the cross sections for singly-produced top quarks at the Fermilab Tevatron are presented. The small expected signals and the large, uncertain backgrounds require careful event selection, sophisticated methods for separating signal events from background events, and data-based background predictions and fits. Both the CDF and D0 col

Benjamin Koch

In this article we show that the fundamental equations of relativistic Bohmian mechanics for a single particle can be derived from a scalar theory of curved space-time.

K. M. Menten, R. Guesten, S. Leurini, S. Thorwirth

Using the Atacama Pathfinder Experiment (APEX) telescope we have detected the rotational ground-state transitions of ortho-ammonia and ortho-water toward the redshift ~0.89 absorbing galaxy in the PKS 1830-211 gravitational lens system. We discuss our observations in the context of recent space-borne data obtained for these lines with the SWAS and Odin satel

Alexander S. Haupt, Andre Lukas, K. S. Stelle

We study the compactification of M-theory on Calabi-Yau five-folds and the resulting N=2 super-mechanics theories. By explicit reduction from 11 dimensions, including both bosonic and fermionic terms, we calculate the one-dimensional effective action and show that it can be derived from an N=2 super-space action. We find that the Kahler and complex structure

Yosuke Mizuno, Bing Zhang, Bruno Giacomazzo, Ken-Ichi Nishikawa

We solve the Riemann problem for the deceleration of an arbitrarily magnetized relativistic flow injected into a static unmagnetized medium in one dimension. We find that for the same initial Lorentz factor, the reverse shock becomes progressively weaker with increasing magnetization σ(the Poynting-to kinetic energy flux ratio), and the shock becomes a raref

Lawrence M. Ioannou, Michele Mosca

Let $\ket{\0}$ and $\ket{\1}$ be two states that are promised to come from known subsets of orthogonal subspaces, but are otherwise unknown. Our paper probes the question of what can be achieved with respect to the basis $\{\ket{\0},\ket{\1}}^{\otimes n}$ of $n$ logical qubits, given only a few copies of the unknown states $\ket{\0}$ and $\ket{\1}$. A phase-

Walter H. Baron, Carmen A. Núñez

We study the operator product expansion in the AdS$_3$ WZNW model. The OPE of primary fields and their spectral flow images is computed from the analytic continuation of the expressions in the H$_3^+$ WZNW model, adding spectral flow. We argue that the symmetries of the affine algebra require a truncation which establishes the closure of the fusion rules on

Y. Kim, T. Sato, F. Myhrer, K. Kubodera

Much effort has been invested on effective-field-theoretical studies of the near-threshold NN \to NNπreactions and, in order to deal with the rather large three-momentum transfers involved, the momentum counting scheme was proposed as an alternative to the usual Weinberg counting scheme. To examine the practical utility of the momentum counting scheme, we st

Jinkui Wan

Generalizing the centralizer construction of Molev and Olshanski on symmetric groups, we study the structures of the centralizer $\mZ_{m,n}$ of the wreath product $G_{n-m}$ in the group algebra of $G_n$ for any $n\geq m$. We establish the connection between $\mZ_{m,n}$ and a generalization of degenerate affine Hecke algebras introduced in our earlier work.

R. Keith Ellis, W. T. Giele, Zoltan Kunszt, Kirill Melnikov

We employ the recently developed method of generalized $D$-dimensional unitarity to compute one-loop virtual corrections to all scattering amplitudes relevant for the production of a $W$ boson in association with three jets in hadronic collisions, treating all quarks as massless.

Jingshan Zhang, Eugene I. Shakhnovich

We study the population dynamics of lytic viruses which replicate slowly in dividing host cells within an organism or cell culture, and find a range of viral replication rates that allows viruses to persist, avoiding extinction of host cells or dilution of viruses at too rapid or too slow viral replication. For the within-host competition between multiple vi

Adityanand Guntuboyina, Hannes Leeb

We derive concentration inequalities for the spectral measure of large random matrices, allowing for certain forms of dependence. Our main focus is on empirical covariance (Wishart) matrices, but general symmetric random matrices are also considered.

William Arveson

A (finite or countably infinite) set G of generators of an abstract C*-algebra A is called hyperrigid if for every faithful representation of A on a Hilbert space $A\subseteq \mathcal B(H)$ and every sequence of unital completely positive linear maps $ϕ_1, ϕ_2,...$ from $\mathcal B(H)$ to itself, $$ \lim_{n\to\infty}\|ϕ_n(g)-g\|=0, \forall g\in G \implies \l

Nicola Pagani

In this work we compute the Chen--Ruan cohomology and the stringy Chow ring of the moduli spaces of smooth and stable $n$-pointed curves of genus 1. We suggest a definition for an Orbifold Tautological Ring in genus 1, which is both a subring of the Chen--Ruan cohomology and of the stringy Chow ring.

Ngoc Phan-Bao, Basmah Riaz, Chin-Fei Lee, Ya-Wen Tang

Studying the earliest stages in the birth of stars is crucial for understanding how they form. Brown dwarfs with masses between that of stars and planets are not massive enough to maintain stable hydrogen-burning fusion reactions during most of their lifetime. Their origins are subject to much debate in recent literature because their masses are far below th

Hongjie Dong, N. V. Krylov

The solvability in Sobolev spaces $W^{1,2}_p$ is proved for nondivergence form second order parabolic equations for $p>2$ close to 2. The leading coefficients are assumed to be measurable in the time variable and two coordinates of space variables, and almost VMO (vanishing mean oscillation) with respect to the other coordinates. This implies the $W^{2}_p$-s

Jose E. Marcos

We present new classes of permutation polynomials over finite fields.

Floriana Giannuzzi

The decay constants and the radiative decay widths of η_b(nS) and η_c(nS) are computed within a semirelativistic quark model, using a potential found through the AdS/QCD correspondence. For η_c, the results are in agreement with experimental data, while in the case of η&#39;_c a discrepancy is found and the possible reasons are discussed.

Pavel Chebotarev

A new class of distances for graph vertices is proposed. This class contains parametric families of distances which reduce to the shortest-path, weighted shortest-path, and the resistance distances at the limiting values of the family parameters. The main property of the class is that all distances it comprises are graph-geodetic: $d(i,j)+d(j,k)=d(i,k)$ if a

Gaofei Zhang

We prove that every bounded type Siegel disk of a rational map must be a quasi-disk with at least one critical point on its boundary. This verifies Douady-Sullivan conjecture for bounded type Siegel disks.

Pavel Chebotarev

For a weighted directed multigraph, let $f_{ij}$ be the total weight of spanning converging forests that have vertex $i$ in a tree converging to $j$. We prove that $f_{ij} f_{jk} = f_{ik} f_{jj}$ if and only if every directed path from $i$ to $k$ contains $j$ (a graph bottleneck equality). Otherwise, $f_{ij} f_{jk} < f_{ik} f_{jj}$ (a graph bottleneck inequa

D. Gross, J. Eisert

We introduce the notion of quantum computational webs: These are quantum states universal for measurement-based computation which can be built up from a collection of simple primitives. The primitive elements - reminiscent of building blocks in a construction kit - are (i) states on a one-dimensional chain of systems (&#34;computational quantum wires&#34;) w

Alex Fink, Benjamin Iriarte Giraldo

We present an elementary type preserving bijection between noncrossing and nonnesting partitions for all classical reflection groups, answering a question of Athanasiadis.

Hilarion L. M. Faliharimalala, Jiang Zeng

In 1997 Clarke et al. studied a $q$-analogue of Euler's difference table for $n!$ using a key bijection $\Psi$ on symmetric groups. In this paper we extend their results to the wreath product of a cyclic group with the symmetric group. In particular we obtain a new mahonian statistic \emph{fmaf} on wreath products. We also show that Foata and Han's two recen

N. Michel, W. Nazarewicz, M. Ploszajczak, T. Vertse

This work reviews foundations and applications of the complex-energy continuum shell model that provides a consistent many-body description of bound states, resonances, and scattering states. The model can be considered a quasi-stationary open quantum system extension of the standard configuration interaction approach for well-bound (closed) systems.

Petra Schwer, Linus Kramer, Richard Weiss

We call a non-discrete Euclidean building a Bruhat-Tits space if its automorphism group contains a subgroup that induces the subgroup generated by all the root groups of a root datum of the building at infinity. This is the class of non-discrete Euclidean buildings introduced and studied by Bruhat and Tits. We give the complete classification of Bruhat-Tits

Ralph Kenna, Hsiao-Ping Hsu, Christian von Ferber

For continuous phase transitions characterized by power-law divergences, Fisher renormalization prescribes how to obtain the critical exponents for a system under constraint from their ideal counterparts. In statistical mechanics, such ideal behaviour at phase transitions is frequently modified by multiplicative logarithmic corrections. Here, Fisher renormal

Damien Prieur

The LHC experiments are close to collecting collision data. An overview of first physics measurements of the W and Z production cross-sections is presented. The electron and muon decay channels are considered. Emphasis will be given to data-driven approaches.

Matteo Carrera, Domenico Giulini

We review attempts to estimate the influence of global cosmological expansion on local systems. Here `local&#39; is taken to mean that the sizes of the considered systems are much smaller than cosmologically relevant scales. For example, such influences can affect orbital motions as well as configurations of compact objects, like black holes. We also discuss

Daniel Meyer

We introduce snowballs, which are compact sets in $\R^3$ homeomorphic to the unit ball. They are 3-dimensional analogs of domains in the plane bounded by snowflake curves. For each snowball $B$ a quasiconformal map $f\colon \R^3\to \R^3$ is constructed that maps $B$ to the unit ball.

W. de Paula, T. Frederico, H. Forkel, M. Beyer

We obtain an explicit solution of the 5d Einstein equations in a dilaton background model. We demonstrate that for each metric ansatz that only depends on the extra coordinate, it is possible to uniquely determine the dilaton field and its potential consistently with the 5d Einstein equation. In this holographic dual model of QCD, conformal symmetry of the A

Jonathan E. Martin, Harvey S. Reall

Eleven-dimensional supergravity admits non-supersymmetric solutions of the form AdS(5)xM(6) where M(6) is a positive Kahler-Einstein space. We show that the necessary and sufficient condition for such solutions to be stable against linearized bosonic supergravity perturbations can be expressed as a condition on the spectrum of the Laplacian acting on (1,1)-f

Tim Gershon

The decay B^0 -> DK^{*0} is well-known to provide excellent potential for a precise measurement of the Unitarity Triangle angle gamma in future experiments. It is noted that the sensitivity can be significantly enhanced by studying the amplitudes relative to those of the flavour-specific decay B^0 -> D_2^{*-}K^+, which can be achieved by analyzing the B^0 ->

Ivan Cheltsov, Jihun Park, Constantin Shramov

We compute global log canonical thresholds of a large class of quasismooth well-formed del Pezzo weighted hypersurfaces in $\mathbb{P}(a_{1},a_{2},a_{3},a_{4})$. As a corollary we obtain the existence of orbifold Kähler--Einstein metrics on many of them, and classify exceptional and weakly exceptional quasismooth well-formed del Pezzo weighted hypersurfaces

D. J. Singh, M. H. Du, L. Zhang, A. Subedi

The layered iron superconductors are discussed using electronic structure calculations. The four families of compounds discovered so far, including Fe(Se,Te) have closely related electronic structures. The Fermi surface consists of disconnected hole and electron cylinders and additional hole sections that depend on the specific material. This places the mate

O. Soe Sorensen, N. Nygaard, P. B. Blakie

We consider an atomic Fermi gas confined in a uniform optical lattice potential, where the atoms can pair into molecules via a magnetic field controlled narrow Feshbach resonance. The phase diagram of the resulting atom-molecule mixture in chemical and thermal equilibrium is determined numerically in the absence of interactions under the constraint of partic

Majid Amooshahi

Modeling an anisotropic spatially and temporarily dispersive magnetodielectric medium by two independent collections of three dimensional vector fields, we demonstrate a fully canonical quantization of electromagnetic field in the presence of such a medium. Two tensor fields which couple the electromagnetic field with the medium and have an important role in

R. H. Liu, T. Wu, G. Wu, H. Chen

The recent discovery of superconductivity in oxypnictides with the critical temperature (TC) higher than McMillan limit of 39 K (the theoretical maximum predicted by Bardeen-Cooper-Schrieffer (BCS) theory) has generated great excitement. Theoretical calculations indicate that the electron-phonon interaction is not strong enough to give rise to such high tran

E. Kh. Akhmedov, Viviana Niro

A simple closed-form analytic expression for the probability of two-flavour neutrino oscillations in a matter with an arbitrary density profile is derived. Our formula is based on a perturbative expansion and allows an easy calculation of higher order corrections. The expansion parameter is small when the density changes relatively slowly along the neutrino

Aidan Robson

The status of W and Z cross-section and width measurements from the CDF and D0 experiments is reviewed. Recent results that are discussed: the cross-section for Z production times the branching ratio to tau pairs, the rapidity and transverse momentum distributions of Z production in the electron channel, and the direct measurements of the W width and the Z i

B. Meirose, A. J. Ramalho

In this paper we analyze the effects of virtual vector bileptons in polarized Bhabha scattering at the energies of the future linear colliders. In order to make the calculations of the differential cross sections more realistic, important beam effects such as initial state radiation, beamstrahlung, beam energy and polarization spreads are accounted for. The

Damien Chablat

In order to optimise the costs and time of design of the new products while improving their quality, concurrent engineering is based on the digital model of these products. However, in order to be able to avoid definitively physical model without loss of information, new tools must be available. Especially, a tool making it possible to check simply and quick

Andrea Longhin

The OPERA experiment, whose aim is the direct observation of nu_mu ~> nu_tau oscillations in appearance mode in the CNGS high-energy neutrino beam, consists of a high-granularity modular target of nuclear emulsions-lead "bricks", richly instrumented with electronic detectors necessary for the location of neutrino interactions and kinematic analysis. After th

Gergely J. Szöllősi, Imre Derényi

Genetic robustness, the preservation of an optimal phenotype in the face of mutations, is critical to the understanding of evolution as phenotypically expressed genetic variation is the fuel of natural selection. The origin of genetic robustness, whether it evolves directly by natural selection or it is a correlated byproduct of other phenotypic traits, is,

P. S. Elamvazhuthi, P. S. Kulkarni, B. K. Dey

In a radio network with single source-destination pair and some relays, a link between any two nodes is considered to have same or zero path loss. However in practice some links may have considerably high path loss than others but still being useful. In this report, we take into account signals received from these links also. \indent Our system model consist

Alastair I. M. Rae

During the last ten years or so, derivations of the Born rule based on decision theory have been proposed and developed, and it is claimed that these are valid in the context of the Everett interpretation. This claim is critically assessed and it is shown that one of its key assumptions, although natural in the context of the Copenhagen interpretation, is no

Ricardo A. Pinto, Jean Pierre Nguenang, Sergej Flach

We investigate the spectrum and eigenstates of a Bose-Hubbard chain containing two bosons with fixed boundary conditions. In the noninteracting case the eigenstates of the system define a two-dimensional normal-mode space. For the interacting case weight functions of the eigenstates are computed by perturbation theory and numerical diagonalization. We identi

Orlagh L. Creevey, Savita Mathur, Rafael A. García

Conventional astrophysical observations have failed to provide stringent constraints on physical processes operating in the interior of the stars. However, satellite missions now promise a solution to these problems by providing long-term high-quality continuous data which will allow the application of seismic techniques. With this in mind, and using the Sun

Crystal Hoyt

We define regular Kac-Moody superalgebras and classify them using integrable modules. We give conditions for irreducible highest weight modules of regular Kac-Moody superalgebras to be integrable. This paper is a major part of the proof for the classification of finite-growth contragredient Lie superalgebras.

Michael Pürrer, Peter C Aichelburg

We study numerically the late-time behaviour of the coupled Einstein Yang-Mills system. We restrict ourselves to spherical symmetry and employ Bondi-like coordinates with radial compactification. Numerical results exhibit tails with exponents close to -4 at timelike infinity $i^+$ and -2 at future null infinity \Scri.

Robert Maiwald, Dietrich Leibfried, Joe Britton, J. C. Bergquist

Small, controllable, highly accessible quantum systems can serve as probes at the single quantum level to study multiple physical effects, for example in quantum optics or for electric and magnetic field sensing. The applicability of trapped atomic ions as probes is highly dependent on the measurement situation at hand and thus calls for specialized traps. P

Thomas Olsen, Jeppe Gavnholt, Jakob Schiøtz

We present a model for Desorption Induce by (Multiple) Electronic Transitions (DIET/DIMET) based on potential energy surfaces calculated with the Delta Self-Consistent Field extension of Density Functional Theory. We calculate potential energy surfaces of CO and NO molecules adsorbed on various transition metal surfaces, and show that classical nuclear dynam

Olga Minaeva, Cristian Bonato, Bahaa E. A. Saleh, David S. Simon

We describe a novel effect involving odd-order dispersion cancellation. We demonstrate that odd- and even-order dispersion cancellation may be obtained in different regions of a single quantum interferogram using frequency-anticorrelated entangled photons and a new type of quantum interferometer. This offers new opportunities for quantum communication and me

F. Loran, H. Soltanpanahi

For the five dimensional N=2 black rings, we study the supersymmetry enhancement and identify the global supergroup of the near horizon geometry. We show that the global part of the supergroup is OSp(4*|2)X U(1) which is similar to the small black string. We show that results obtained by applying the entropy function formalism, the c-extremization approach a

J. N. De, S. K. Samaddar

Based on the general analysis of the grand canonical partition function in the S-matrix framework, the calculated results on symmetry energy, free energy and entropy of dilute warm nuclear matter are presented. At a given temperature and density, the symmetry energy or symmetry free energy of the clusterized nuclear matter in the S-matrix formulation deviate

Martin W. Grunewald

The prospects for electroweak measurements at the Large Hadron Collider (LHC) are discussed. In addition to high-luminosity results, special emphasis is placed on early start-up measurements with a total luminosity ranging from 10/pb to 100/pb, using the general-purpose detectors ATLAS and CMS and their initially larger calibration and alignment uncertaintie

Yuri Trakhinin

We study the free boundary problem for the equations of compressible Euler equations with a vacuum boundary condition. Our main goal is to recover in Eulerian coordinates the earlier well-posedness result obtained by Lindblad [Lindblad H., Commun. Math. Phys. 260 (2005), 319-392] for the isentropic Euler equations and extend it to the case of full gas dynami

Rong-Gen Cai, Li-Ming Cao, Ya-Peng Hu, Sang Pyo Kim

We present a kind of generalized Vaidya solutions in a generic Lovelock gravity. This solution generalizes the simple case in Gauss-Bonnet gravity reported recently by some authors. We study the thermodynamics of apparent horizon in this generalized Vaidya spacetime. Treating those terms except for the Einstein tensor as an effective energy-momentum tensor i

Eric Fusy, Dominique Poulalhon, Gilles Schaeffer

We present a bijection between some quadrangular dissections of an hexagon and unrooted binary trees, with interesting consequences for enumeration, mesh compression and graph sampling. Our bijection yields an efficient uniform random sampler for 3-connected planar graphs, which turns out to be determinant for the quadratic complexity of the current best kno

Eric Fusy

This article presents new bijections on planar maps. At first a bijection is established between bipolar orientations on planar maps and specific &#34;transversal structures&#34; on triangulations of the 4-gon with no separating 3-cycle, which are called irreducible triangulations. This bijection specializes to a bijection between rooted non-separable maps a

J. Carnahan, H. Honkanen, S. Liuti, Y. Loitiere

Neural network algorithms have been recently applied to construct Parton Distribution Function (PDF) parametrizations which provide an alternative to standard global fitting procedures. We propose a technique based on an interactive neural network algorithm using Self-Organizing Maps (SOMs). SOMs are a class of clustering algorithms based on competitive lear

Chenyang Xu

We discuss the strong rational connectedness of smooth rationally connected surfaces. We prove in lots of cases, including the smooth locus of a log del Pezzo surface, the rational connectedness indeed implies the strong rational conectedness. This confirms a conjecture due to Hassett and Tschinkel in \cite{ht08}.

Andrew R. Wetzel, J. D. Cohn, Martin White

Galaxies are believed to be in one-to-one correspondence with simulated dark matter subhalos. We use high-resolution N-body simulations of cosmological volumes to calculate the statistical properties of subhalo (galaxy) major mergers at high redshift (z=0.6-5). We measure the evolution of the galaxy merger rate, finding that it is much shallower than the mer

Zhi Ren, Xiao Lin, Qian Tao, Shuai Jiang

We present a systematic study on the physical properties of EuFe$_{2-x}$Ni$_{x}$As$_{2}$ (0$\leq$\emph{x}$\leq$0.2) by electrical resistivity, magnetic susceptibility and thermopower measurements. The undoped compound EuFe$_{2}$As$_{2}$ undergoes a spin-density-wave (SDW) transition associated with Fe moments at 195 K, followed by antiferromagnetic (AFM) ord

Chao-Jun Feng

The holographic dark energy with Ricci scalar as IR cutoff called Ricci dark energy(RDE) probes the nature of dark energy with respect to the holographic principle of quantum gravity theory. The scalar field dark energy models like quintom are often viewed as effective description of the underlying field theory of dark energy. In this letter, we assume RDE m

JLQCD, TWQCD collaborations, :, T. Kaneko

We calculate the pion vector and scalar form factors in two-flavor QCD. Gauge configurations are generated with dynamical overlap quarks on a 16^3 x 32 lattice at a lattice spacing of 0.12 fm with sea quark masses down to a sixth of the physical strange quark mass. Contributions of disconnected diagrams to the scalar form factor is calculated employing the a

Sumei Huang, G. S. Agarwal

It is shown that an optical parametric amplifier inside a cavity can considerably improve the cooling of the micromechanical mirror by radiation pressure. The micromechanical mirror can be cooled from room temperature 300 K to sub-Kelvin temperatures, which is much lower than what is achievable in the absence of the parametric amplifier. Further if in case o

Netanel H. Lindner, Terry Rudolph

We present a method to convert certain single photon sources into devices capable of emitting large strings of photonic cluster state in a controlled and pulsed &#34;on demand&#34; manner. Such sources would greatly reduce the resources required to achieve linear optical quantum computation. Standard spin errors, such as dephasing, are shown to affect only 1

Monika H. Schleier-Smith, Ian D. Leroux, Vladan Vuletić

We generate entangled states of an ensemble of 5*10^4 rubidium-87 atoms by optical quantum nondemolition measurement. The resonator-enhanced measurement leaves the atomic ensemble, prepared in a superposition of hyperfine clock levels, in a squeezed spin state. By comparing the resulting reduction of quantum projection noise (up to 8.8(8) dB) with the concom

Saburo Kakei, Michitomo Nishizawa, Yoshihisa Saito, Yoshihiro Takeyama

We construct special solutions to the rational quantum Knizhnik-Zamolodchikov equation associated with the Lie algebra $gl_N$. The main ingredient is a special class of the shifted non-symmetric Jack polynomials. It may be regarded as a shifted version of the singular polynomials studied by Dunkl. We prove that our solutions contain those obtained as a scali

Mikhail Batygov, Stephen Dye, John Learned, Shigenobu Matsuno

Despite the dramatic progress made in neutrino oscillation studies recently, several fundamental neutrino parameters remain either unknown or poorly measured. We discuss in detail a method for their measurement by precision studies of oscillation-caused neutrino energy spectrum distortions, for which a large underwater inverse beta decay detector appears to

Zotin K. -H. Chu

The objective of this paper is to share our enthusiasm for optical pumping experiments and to encourage their use in researches on practical physics. The experimental technique has been well developed and the apparatus sophisticated, but, by paying attention to a few details, reliable operation can be repeated. Some theoretical principles for optical pumping

Stephen Lack, Jiri Rosicky

Categorical universal algebra can be developed either using Lawvere theories (single-sorted finite product theories) or using monads, and the category of Lawvere theories is equivalent to the category of finitary monads on Set. We show how this equivalence, and the basic results of universal algebra, can be generalized in three ways: replacing Set by another

Morris R. Flynn, Aslan R. Kasimov, Jean-Christophe Nave, Rodolfo R. Rosales

In analogy to gas-dynamical detonation waves, which consist of a shock with an attached exothermic reaction zone, we consider herein nonlinear traveling wave solutions, termed &#34;jamitons,&#34; to the hyperbolic (&#34;inviscid&#34;) continuum traffic equations. Generic existence criteria are examined in the context of the Lax entropy conditions. Our analys

Astrid an Huef, S. Kaliszewski, Iain Raeburn, Dana P. Williams

Suppose that a locally compact group $G$ acts freely and properly on the right of a locally compact space $T$. Rieffel proved that if $α$ is an action of $G$ on a $C^*$-algebra $A$ and there is an equivariant embedding of $C_0(T)$ in $M(A)$, then the action $α$ of $G$ on $A$ is proper, and the crossed product $A\rtimes_{α,r}G$ is Morita equivalent to a gener

Aijun Du, Jinqiao Duan, Hongjun Gao

The stochastics two-layer quasi-geostrophic flow model is an intermediate system between the single-layer two dimensional barotropic flow model and the continuously stratified three dimensional baroclinic flow model. This model is widely used to investigate basic mechanisms in geophysical flows, such as baroclinic effects, the Gulf Stream and subtropical gyr

R. G. Moore, M. D. Lumsden, M. B. Stone, Jiandi Zhang

Inelastic neutron scattering is used to measure the temperature dependent phonon dispersion in Ca$_{2-x}$Sr$_{x}$RuO$_{4}$ ($x=0.4$, 0.6). The in-plane $Σ_{4}$ octahedral tilt mode softens significantly at the zone boundary of the high temperature tetragonal (HTT) \textit{I4}$_{\mathit{1}}$\textit{/acd} structure as the temperature approaches the transition

S. J. Kleinman, J. E. Gunn, B. Boroski, D. Long

Astronomy is changing. Large projects, large collaborations, and large budgets are becoming the norm. The Sloan Digital Sky Survey (SDSS) is one example of this new astronomy, and in operating the original survey, we put in place and learned many valuable operating principles. Scientists sometimes have the tendency to invent everything themselves but when bu

Lendert Gelens, Damia Gomila, Guy Van der Sande, Jan Danckaert

In this work we characterize the dynamical instabilities of localized structures exhibited by a recently introduced Gelens et al., Phys. Rev. A 75, 063812 2007 generalization of the Lugiato-Lefever model that includes a weakly nonlocal response of an intracavity metamaterial. A rich scenario, in which the localized structures exhibit different types of oscil

Ivan Vitev, Simon Wicks, Ben-Wei Zhang

For jets, with great power comes great opportunity. The unprecedented center of mass energies available at the LHC open new windows on the QGP: we demonstrate that jet shape and jet cross section measurements become feasible as a new, differential and accurate test of the underlying QCD theory. We present a first step in understanding these shapes and cross

V. A. Golovko

The paper is devoted to further development of the new approach in equilibrium statistical mechanics the basis of which was worked out in a series of articles by the author. The approach proceeds on the use of a hierarchy of equations for reduced density matrices in the case of thermodynamic equilibrium. The present paper deals with a system containing parti

W. Cassing, E. L. Bratkovskaya, Y. -. Z. Xing

The hadronization of an expanding partonic fireball is studied within the Parton-Hadron-Strings Dynamics (PHSD) approach which is based on a dynamical quasiparticle model (DQPM) matched to reproduce lattice QCD results in thermodynamic equilibrium. Apart from strong parton interactions the expansion and development of collective flow is found to be driven by

John A. Regan, Martin G. Haehnelt

Large dynamic range numerical simulations of atomic cooling driven collapse of gas in pre-galactic DM haloes with T_vir ~ 10000 K show that the gas loses 90% and more of its angular momentum before rotational support sets in. In a fraction of these haloes where the metallicity is low and UV radiation suppresses H_2 cooling, conditions are thus very favourabl

F. D. A. Hartwick

Based on the earlier work of Gunn and McCrea we model the formation of globular clusters in merging galaxies. Neutral hydrogen observations of dwarf irregular galaxies as well as more luminous systems are used to provide the key parameters of the model. The observations indicate that clusters with the mass of globular clusters should still be forming today.

B. W. Mintz, A. Bessa, E. S. Fraga

We present numerical results on bubble profiles, nucleation rates and time evolution for a weakly first-order quark-hadron phase transition in different expansion scenarios. We confirm the standard picture of a cosmological first-order phase transition, in which the phase transition is entirely dominated by nucleation. We also show that, even for expansion r

S. Hekker, C. Barban, T. Kallinger, W. Weiss

Asteroseismic observations from space can provide us with long time series of uninterrupted high quality data for many stars at the same time. The CoRoT satellite (Convection Rotation and planetary Transits) was launched successfully in December 2006 and provides high precision photometery for a large number of stars. Here we present our research on (late G

C. Russo, H. G. Barros, A. Stute, F. Dubin

We describe an ion-based cavity-QED system in which the internal dynamics of an atom is coupled to the modes of an optical cavity by vacuum-stimulated Raman transitions. We observe Raman spectra for different excitation polarizations and find quantitative agreement with theoretical simulations. Residual motion of the ion introduces motional sidebands in the

A. Saro, S. Borgani, L. Tornatore, G. De Lucia

We present results from two high-resolution hydrodynamical simulations of proto-cluster regions at z~2.1. The simulations have been compared to observational results for the socalled Spiderweb galaxy system, the core of a putative proto-cluster region at z = 2.16, found around a radio galaxy. The simulated regions have been chosen so as to form a poor cluste

J. Santiago-Garcia, M. Tafalla, D. Johnstone, R. Bachiller

Context: IRAS 04166+2706 in Taurus is one of the most nearby young stellar objects whose molecular outflow contains a highly collimated fast component. Methods: We have observed the IRAS 04166+2706 outflow with the IRAM Plateau de Bure interferometer in CO(J=2-1) and SiO(J=2-1) achieving angular resolutions between 2&#39;&#39; and 4&#39;&#39;. To improve the

Iwan M. Duursma, Seungkook Park

For a given curve X and divisor class C, we give lower bounds on the degree of a divisor A such that A and A-C belong to specified semigroups of divisors. For suitable choices of the semigroups we obtain (1) lower bounds for the size of a party A that can recover the secret in an algebraic geometric linear secret sharing scheme with adversary threshold C, an

Naveen A. Reddy, Charles C. Steidel

We use the deep ground-based optical photometry of the Lyman Break Galaxy (LBG) Survey to derive robust measurements of the faint-end slope (alpha) of the UV LF at redshifts 1.9<z<3.4. Our sample includes >2000 spectroscopic redshifts and ~31000 LBGs in 31 spatially-independent fields over a total area of 3261 arcmin^2. These data allow us to select galaxies

Bruno Bellomo, Rosario Lo Franco, Giuseppe Compagno

We investigate how nonlocal entanglement, as identified by violations of a Bell inequality, may be protected during the evolution. Our system consists of two qubits each embedded in a bosonic reservoir evolving independently and initially in an entangled mixed state. We show that the violation of the Bell inequality can be related to the single-qubit populat

Jin Lu, José M. F. Moura

In this paper, we propose a linear complexity encoding method for arbitrary LDPC codes. We start from a simple graph-based encoding method ``label-and-decide.&#39;&#39; We prove that the ``label-and-decide&#39;&#39; method is applicable to Tanner graphs with a hierarchical structure--pseudo-trees-- and that the resulting encoding complexity is linear with th

Henriette Elvang, Pau Figueras, Gary T. Horowitz, Veronika E. Hubeny

We study mergers of ergoregions in $d+1$-dimensional vacuum gravity. At the merger point, where the ergosurfaces bounding each ergoregion just touch, solutions exhibit universal behavior when there is rotation only in one plane: the angle between the merging ergosurfaces depends only on the symmetries of the solution, not on any other details of the configur

Martin Hairer, Jonathan C. Mattingly

The aim of this note is to present an elementary proof of a variation of Harris&#39; ergodic theorem of Markov chains. This theorem, dating back to the fifties essentially states that a Markov chain is uniquely ergodic if it admits a ``small&#39;&#39; set which is visited infinitely often. This gives an extension of the ideas of Doeblin to the unbounded stat

F. M. Paiva, A. F. F. Teixeira

A plane lights on monochromatically and immediately after lights off, while an observer starts moving out from the plane, perpendicularly to it, with constant proper acceleration. Special relativity predicts that the observer will see a light circle always in the direction opposite to the plane, without Doppler effect, and that the circle will seem to progre

Jie Sun, Erik M. Bollt, Takashi Nishikawa

We derive variational equations to analyze the stability of synchronization for coupled near-identical oscillators. To study the effect of parameter mismatch on the stability in a general fashion, we define master stability equations and associated master stability functions, which are independent of the network structure. In particular, we present several e

S. H. Hassanzadeh, N. Shirmohammadi, H. Zakeri

In this paper, after giving a criterion for a Noetherian local ring to be quasi-Gorenstein, we obtain some sufficient conditions for a quasi- Gorenstein ring to be Gorenstein. In the course, we provide a slight generalization of a theorem of Evans and Griffith.