March 2006 arXiv papers — page 16

A. S. Dzhumadil'daev

Skew-symmetric sum of $N!$ compositions of $N$ vector fields in all possible order is called $N$-commutator. We construct 10-commutator and 13-commutator on a space of vector fields $Vect(3)$ and 10-commutator on a space of divergenceless vector fields $Vect_0(3).$

José Antonio Vallejo

Traditionally, the discussion about the geometrical interpretation of inertial forces is reserved for General Relativity handbooks. In these notes an analysis of the effect of such forces in a classical (newtonian) context is made, as well as a study of the relation between the precession of the Foucault pendulum and the holonomy on a surface, including some

Kamel Berriri, A. -S. Bonnet-Ben Dhia, P. Joly

In this paper we are interested in the mathematical and numerical analysis of the time-dependent Galbrun equa- tion in a rigid duct. This equation models the acoustic propagation in presence of flow [1]. We propose a regu- larized variational formulation of the problem, in the sub- sonic case, suitable for an approximation by Lagrange finite elements, and co

Viet-Anh Nguyen

We first introduce the class of quasi-algebraically stable meromorphic maps of $¶^k.$ This class is strictly larger than that of algebraically stable meromorphic self-maps of $¶^k.$ Then we prove that all maps in the new class enjoy a recurrent property. In particular, the algebraic degrees for iterates of these maps can be computed and their first dynamical

Momar Dieng, Craig A. Tracy

This is an expository account of the edge eigenvalue distributions in random matrix theory and their application in multivariate statistics. The emphasis is on the Painlevé representations of these distributions.

Sarah Bailey, Michael Keane, Karl Petersen, Ibrahim Salama

The Euler graph has vertices labelled (n,k) for n=0,1,2,... and k=0,1,...,n, with k+1 edges from (n,k) to (n+1,k) and n-k+1 edges from (n,k) to (n+1,k+1). The number of paths from (0,0) to (n,k) is the Eulerian number A(n,k), the number of permutations of 1,2,...,n+1 with exactly n-k falls and k rises. We prove that the adic (Bratteli-Vershik) transformation

Patrick Cattiaux, Guillin Arnaud, Malrieu Florent

We use here a particle system to prove a convergence result as well as a deviation inequality for solutions of granular media equation when the confinement potential and the interaction potential are no more uniformly convex. Proof is straightforward, simplifying deeply proofs of Carrillo-McCann-Villani \cite{CMV,CMV2} and completing results of Malrieu \cite

Ethan Akin, Eli Glasner, Benjamin Weiss

We describe a self-homeomorphism $R$ of the Cantor set $X$ and then show that its conjugacy class in the Polish group $H(X)$ of all homeomorphisms of $X$ forms a dense $G_δ$ subset of $H(X)$. We also provide an example of a locally compact, second countable topological group which has a dense conjugacy class.

J. -P. Francoise, N. Roytvarf, Y. Yomdin

We consider an Abel polynomial differential equation. For two given points a and b, the "Poincare mapping" of the equation transforms the values of its solution at a into their values at b. In this article, we study global analytic properties of the Poincare mapping, in particular, its analytic continuation, its singularities and its fixed points. On

Geert Van de Weyer

We give a description of the bimodule of double derivations DDer(S) of a finite dimensional semi-simple algebra S and its double Schouten bracket in terms of a quiver. This description is used to determine which degree two monomials in T_SDDer(S) induce double Poisson brackets on S. In case S = C^n, a criterion for any degree two element to give a double Poi

Jennie C. Hansen, Jerzy Jaworski

We introduce a new random mapping model, $T_n^{\hat D}$, which maps the set $\{1,2,...,n\}$ into itself.The random mapping $T_n^{\hat D}$ is constructed using a collection of exchangeable random variables $\hat{D}_1, ....,\hat{D}_n$ which satisfy $\sum_{i=1}^n\hat{D}_i=n$. In the random digraph,$G_n^{\hat D}$, which represents the mapping $T_n^{\hat D}$, the

Lucio Bedulli, Anna Gori

In this note we show that Hamiltonian stable minimal Lagrangian submanifolds of projective space need not have parallel second fundamental form.

Guillaume Lecué

We consider the problem of optimality, in a minimax sense, and adaptivity to the margin and to regularity in binary classification. We prove an oracle inequality, under the margin assumption (low noise condition), satisfied by an aggregation procedure which uses exponential weights. This oracle inequality has an optimal residual: $(\log M/n)^{κ/(2κ-1)}$ wher

E. Frenkel, D. Gaitsgory

We study the Wakimoto modules over the affine Kac-Moody algebras at the critical level from the point of view of the equivalences of categories proposed in our previous works, relating categories of representations and certain categories of sheaves. In particular, we describe explicitly geometric realizations of the Wakimoto modules as Hecke eigen-D-modules

David Wright

The Jacobian Conjecture has been reduced to the symmetric homogeneous case. In this paper we give an inversion formula for the symmetric case and relate it to a combinatoric structure called the Grossman-Larson Algebra. We use these tools to prove the symmetric Jacobian Conjecture for the case $F=X-H$ with $H$ homogeneous and $JH^{3}=0$. Other special result

Raymond Curran, Eduardo Cattani

We study the $A$-discriminant of toric varieties. We reduce its computation to the case of irreducible configurations and describe its behavior under specialization of some of the variables to zero. We prove a Gale dual characterization of dual defect toric varieties and deduce from it the classsification of such varieties in codimension less than or equal t

Satoshi Murai, Takayuki Hibi

Let $A = K[x_1, ..., x_n]$ denote the polynomial ring in $n$ variables over a field $K$ of characteristic 0 with each $°x_i = 1$. Given arbitrary integers $i$ and $j$ with $2 \leq i \leq n$ and $3 \leq j \leq n$, we will construct a monomial ideal $I \subset A$ such that (i) $β_k(I) < β_k(\Gin(I))$ for all $k < i$, (ii) $β_i(I) = β_i(\Gin(I))$, (iii) $β_\ell

I-Chiau Huang

Introduction revised, representations of generalized power series reformulated, references updated.

Cynthia Farthing, Paul S. Muhly, Trent Yeend

We provide inverse semigroup and groupoid models for the Toeplitz and Cuntz-Krieger algebras of finitely aligned higher-rank graphs. Using these models, we prove a uniqueness theorem for the Cuntz-Krieger algebra.

Horatiu Nastase

We revisit the issue of the RHIC ``fireball&#39;&#39; as a dual black hole, and explain some of the details. We discuss the nature of the (black hole) information paradox as a purely field theory (gauge theory) phenomenon and how the paradox can be formulated in exactly the same way for the RHIC fireball and a black hole. We stress the differences between th

E. C. Marino

We consider quantum global vortex string correlation functions, within the Kalb-Ramond framework, in the presence of a background field-strength tensor and investigate the conditions under which this yields a nontrivial contribution to those correlation functions. We show that a background field must be supplemented to the Kalb-Ramond theory, in order to cor

Richard Atkins

It is shown that the string concept results naturally from considerations of gravitation. This paper describes a derivation of linearized general relativity based upon the hypotheses of special covariance and the existence of a gravitational potential. The gravitational field possesses gauge invariance given by a second-order covariant derivative defining an

Horatiu Nastase

We argue that the fireball observed at RHIC is (the analog of) a dual black hole. In previous works, we have argued that the large $s$ behaviour of the total QCD cross section is due to production of dual black holes, and that in the QCD effective field theory it corresponds to a nonlinear soliton of the pion field. Now we argue that the RHIC fireball is thi

Hugo Garcia-Compean

In this paper we survey some of the relations between Plebanski description of self-dual gravity through the heavenly equations and the physics (and mathematics) of N=2 Strings. In particular we focus on the correspondence between the infinite hierarchy in the ground ring structure of BRST operators and its associated Boyer-Plebanski construction of infinite

Barbara Jager, Carlo Oleari, Dieter Zeppenfeld

Vector-boson fusion processes constitute an important class of reactions at hadron colliders, both for signals and backgrounds of new physics in the electroweak interactions. We consider what is commonly referred to as W+W- production via vector-boson fusion (with subsequent leptonic decay of the Ws), or, more precisely, e+ nu_e mu- nubar_mu + 2 jets product

S. S. Afonin

A new relation between $ρ$-meson mass, weak $π$-meson decay constant, quark and gluon condensates is derived from the QCD sum rules. As a byproduct an explanation for the dominance of $ρρ$-decay for the $f_0(1370)$-meson is proposed.

Christopher G. Lester

Considering the cascade decay $D\to c C \to c b B \to c b a A$ in which $D,C,B,A$ are massive particles and $c,b,a$ are massless particles, we determine for the first time the shape of the distribution of the invariant mass of the three massless particles $m_{abc}$ for the sub-set of decays in which the invariant mass $m_{ab}$ of the last two particles in th

Masafumi Koike, Naotoshi Okamura, Masako Saito, Tatsu Takeuchi

We consider a search for the CP-violating angle deltaCP in long baseline neutrino oscillation experiments. We show that the subleading deltaCP-dependent terms in the nu_mu -> nu_e oscillation probability can be easily obscured by the ambiguity of the leading term which depends on |dm^2_31|. It is thus necessary to determine the value of dm^2_31 with a suffic

A. Tawfik

The in-medium modifications of hadron properties are briefly discussed. We restrict the discussion to the lattice QCD calculations for the hadron masses, screening masses, decay constants and wave functions. We review the progress made so far and describe how to broaden its horizon.

The DELPHI Collaboration, J. Abdallah

An experimental study of the normalized three-jet rate of b quark events with respect to light quarks events (light= \ell \equiv u,d,s) has been performed using the CAMBRIDGE and DURHAM jet algorithms. The data used were collected by the DELPHI experiment at LEP on the Z peak from 1994 to 2000. The results are found to agree with theoretical predictions trea

The DELPHI Collaboration, J. Abdallah

A search for excited lepton production in e+e- collisions was performed using the data collected by the DELPHI detector at LEP at centre-of-mass energies ranging from 189 GeV to 209 GeV, corresponding to an integrated luminosity of approximately 600 pb^{-1}. No evidence for excited lepton production was found. In searches for pair-produced excited leptons, l

The DELPHI Collaboration, J. Abdallah

The exclusive and semi-exclusive branching ratios of the tau lepton hadronic decay modes (h- v_t, h- pi0 v_t, h- pi0 pi0 v_t, h- \geq 2pi0 v_t, h- \geq 3pi0 v_t, 2h- h+ v_t, 2h- h+ pi0 v_t, 2h- h+ \geq 2pi0 v_t, 3h- 2h+ v_t and 3h- 2h+ \geq 1pi0 v_t) were measured with data from the DELPHI detector at LEP.

Francisco S. N. Lobo

A possible candidate for the present accelerated expansion of the Universe is &#39;&#39;phantom energy&#39;&#39;, which possesses an equation of state of the form $ω\equiv p/ρ<-1$, consequently violating the null energy condition. As this is the fundamental ingredient to sustain traversable wormholes, this cosmic fluid presents us with a natural scenario for

Rodolfo Gambini, Rafael Porto, Jorge Pullin

We present a discussion of the fundamental loss of unitarity that appears in quantum mechanics due to the use of a physical apparatus to measure time. This induces a decoherence effect that is independent of any interaction with the environment and appears in addition to any usual environmental decoherence. The discussion is framed self consistently and aime

C. Barcelo, A. Cano, L. J. Garay, G. Jannes

We examine the linear stability of various configurations in Bose-Einstein condensates with sonic horizons. These configurations are chosen in analogy with gravitational systems with a black hole horizon, a white hole horizon and a combination of both. We discuss the role of different boundary conditions in this stability analysis, paying special attention t

Tomislav Prokopec

We argue that, when coupled to Einstein&#39;s theory of gravity, the Yukawa theory may solve the cosmological constant problem in the following sense: The radiative corrections of fermions generate an effective potential for the scalar field, such that the effective cosmological term Lambda_eff is dynamically driven to zero. Thence, for any initial positive

Domenico Giulini

In the first part of this paper I review some of the difficulties that seem to obstruct generally valid definitions of &#34;general covariance&#34; and/or &#34;background independence&#34; The second and more historical part deals with a rather strange argument that Einstein put forward in his 1913 &#34;Entwurf paper&#34; with M. Grossmann to discredit scala

Lawrence M. Ioannou, Benjamin C. Travaglione, Donny Cheung

Let $K$ be a full-dimensional convex subset of $\mathbb{R}^n$. We describe a new polynomial-time Turing reduction from the weak separation problem for $K$ to the weak optimization problem for $K$ that is based on a geometric heuristic. We compare our reduction, which relies on analytic centers, with the standard, more general reduction.

Himanshu Thapliyal, Saurabh Kotiyal, M. B Srinivas

IEEE 754r is the ongoing revision to the IEEE 754 floating point standard and a major enhancement to the standard is the addition of decimal format. This paper proposes two novel BCD adders called carry skip and carry look-ahead BCD adders respectively. Furthermore, in the recent years, reversible logic has emerged as a promising technology having its applic

Arijit Ganguly, Abhishek Agrawal, P. Oscar Boykin, Renato Figueiredo

Peer-to-peer (P2P) networks have mostly focused on task oriented networking, where networks are constructed for single applications, i.e. file-sharing, DNS caching, etc. In this work, we introduce IPOP, a system for creating virtual IP networks on top of a P2P overlay. IPOP enables seamless access to Grid resources spanning multiple domains by aggregating th

Joel Le Roux, Philippe Chaurand, Mickael Urrutia

This communication describes a representation of images as a set of edges characterized by their position and orientation. This representation allows the comparison of two images and the computation of their similarity. The first step in this computation of similarity is the seach of a geometrical basis of the two dimensional space where the two images are r

Uriel Feige, Eran Ofek

Let $ϕ$ be a 3CNF formula with n variables and m clauses. A simple nonconstructive argument shows that when m is sufficiently large compared to n, most 3CNF formulas are not satisfiable. It is an open question whether there is an efficient refutation algorithm that for most such formulas proves that they are not satisfiable. A possible approach to refute a f

Ashutosh Deepak Gore, Abhay Karandikar

We derive the maximum entropy of a flow (information utility) which conforms to traffic constraints imposed by a generalized token bucket regulator, by taking into account the covert information present in the randomness of packet lengths. Under equality constraints of aggregate tokens and aggregate bucket depth, a generalized token bucket regulator can achi

Mirela Damian, Robin Flatland, Joseph O&#39;Rourke

An unfolding of a polyhedron is produced by cutting the surface and flattening to a single, connected, planar piece without overlap (except possibly at boundary points). It is a long unsolved problem to determine whether every polyhedron may be unfolded. Here we prove, via an algorithm, that every orthogonal polyhedron (one whose faces meet at right angles)

L. Viciu, Q. Huang, R. J. Cava

The crystal structure and oxygen stoichiometry in two-layer Na0.74CoO2 and Na0.38CoO2 at room temperature are analyzed by powder neutron diffraction. Two sets of diffraction data for each sample, taken at different incident neutron wavelengths, lambda=1.1968 Angstroms and lambda=1.5403 Angstroms, are analyzed simultaneously by the Rietveld method, allowing f

J. Planelles, J. L. Movilla

The role of image charges in nanoporous semiconductor materials is investigated within the framework of the effective mass and envelope function approximations. We show that nanometric air bubbles in these materials can act as electron-trapping centers. This trapping capability originates from a deep stabilizing self-polarization potential well induced by th

A. T. Hammack, M. Griswold, L. V. Butov, L. E. Smallwood

Optical trapping and manipulation of neutral particles has led to a variety of experiments from stretching DNA-molecules to trapping and cooling of neutral atoms. An exciting recent outgrowth of the technique is an experimental implementation of atom Bose-Einstein condensation. In this paper, we propose and demonstrate laser induced trapping for a new system

Takuma Ohashi, Norio Kawakami, Hirokazu Tsunetsugu

We investigate the Mott transition in the Kagomé lattice Hubbard model using a cluster extension of dynamical mean field theory. The calculation of the double occupancy, the density of states, the static and dynamical spin correlation functions demonstrates that the system undergoes the first-order Mott transition at the Hubbard interaction $U/W \sim 1.4$ ($

T. Gericke, F. Gerbier, A. Widera, S. Foelling

We experimentally investigate the adiabatic loading of a Bose-Einstein condensate into an optical lattice potential. The generation of excitations during the ramp is detected by a corresponding decrease in the visibility of the interference pattern observed after free expansion of the cloud. We focus on the superfluid regime, where we show that the limiting

S. Picozzi, M. Lezaic, S. Blügel

First-principles simulations have been performed for [001]-ordered Mn/Ge and Mn/GaAs &#34;digital alloys&#34;, focusing on the effects of i) a larger band-gap and ii) a different semiconducting host on the electronic structure of the magnetic semiconductors of interest. Our results for the exchange constants in Mn/Ge, evaluated using a frozen-magnon scheme,

J. I. Climente, J. Planelles, M. Barranco, F. Malet

The ground state structure of few-electron concentric double quantum rings is investigated within the local spin density approximation. Signatures of inter-ring coupling in the addition energy spectrum are identified and discussed. We show that the electronic configurations in these structures can be greatly modulated by the inter-ring distance: At short and

Subir K. Das, Juergen Horbach, Kurt Binder, Michael E. Fisher

A symmetrical binary, A+B Lennard-Jones mixture is studied by a combination of semi-grandcanonical Monte Carlo (SGMC) and Molecular Dynamics (MD) methods near a liquid-liquid critical temperature $T_c$. Choosing equal chemical potentials for the two species, the SGMC switches identities (${\rm A} \to {\rm B} \to {\rm A}$) to generate well-equilibrated config

Damien Bensimon, Roland Zeyher

Phase fluctuations of a d-wave superconducting order parameter are theoretically studied in the context of high-T$_c$ cuprates. We consider the $t-J$ model describing layered compounds, where the Heisenberg interaction is decoupled by a d-wave order parameter in the particle-particle channel. Assuming first that the equilibirum state has long-range phase ord

Ivan Junier

We propose a new class of phenomenological models for dynamic glass transitions. The system consists of an ensemble of mesoscopic regions to which local energies are allocated. At each time step, a region is randomly chosen and a new local energy is drawn from a distribution that self-consistently depends on the global energy of the system. Then, the transit

Eric Vincent

In this paper, we review the general features of the out-of-equilibrium dynamics of spin glasses. We use this example as a guideline for a brief description of glassy dynamics in other disordered systems like structural and polymer glasses, colloids, gels etc. Starting with the simplest experiments, we discuss the scaling laws used to describe the isothermal

T. Katuwal, V. Sandu, B. J. Taylor, M. B. Maple

The nature of the out-of-plane dissipation was investigated in underdoped $Y_{0.54}Pr_{0.46}Ba_{2}Cu_{3}O_{7-δ}$ single crystals at temperatures close to the critical temperature. For this goal, temperature and angle dependent out-of-plane resistivity measurements were carried out both below and above the critical temperature. We found that the Ambegaokar-Ha

G. D. Allison, E. A. Galaktionov, A. K. Savchenko, S. S. Safonov

We perform combined resistivity and compressibility studies of two-dimensional hole and electron systems which show the apparent metal-insulator transition - a crossover in the sign of dR/dT with changing density. No thermodynamic anomalies have been detected in the crossover region. Instead, despite a ten-fold difference in r_s, the compressibility of both

Emmanuel Pereira, Ricardo Falcao

We analytically study heat conduction in a chain with interparticle interaction V(x)=lambda[1-cos(x)] and harmonic on-site potential. We start with each site of the system connected to a Langevin heat bath, and investigate the case of small coupling for the interior sites in order to understand the behavior of the system with thermal reservoirs at the bounda

F. Lo Verso, R. L. C. Vink, D. Pini, L. Reatto

We extensively investigated the critical behavior of mixtures of colloids and polymers via the two-component Asakura-Oosawa model and its reduction to a one-component colloidal fluid using accurate theoretical and simulation techniques. In particular the theoretical approach, hierarchical reference theory [Adv. Phys. 44, 211 (1995)], incorporates realistical

Jie Lu, Sun Yin, Z. Z. Sun, X. R. Wang

Proximity effect on field-effect characteristic (FEC) in double-wall carbon nanotubes (DWCNTs) is investigated. In a semiconductor-metal (S-M) DWCNT, the penetration of electron wavefunctions in the metallic shell to the semiconducting shell turns the original semiconducting tube into a metal with a non-zero local density of states at the Fermi level. By usi

Carsten Aits, Ute Löw, Andreas Klümper, Werner Weber

We present a study of the magnetic order and the structural stability of two-dimensional quantum spin systems in the presence of spin-lattice coupling. For a square lattice it is shown that the plaquette formation is the most favourable form of static two-dimensional dimerization. We also demonstrate that such distortions may coexist with long range magnetic

J. Bergli, Y. M. Galperin, B. L. Altshuler

The decoherence of a qubit due to a classical non-Gaussian noise with correlation time longer than the decoherence time is discussed for arbitrary working points of the qubit. A method is developed that allows an exact formula for the phase memory functional in the presence of independent random telegraph noise sources to be derived.

A. Komnik, H. Saleur

We study the statistics of charge transfer through an impurity in a chiral Luttinger liquid (realized experimentally as a quantum point contact in a fractional quantum Hall edge state device). Taking advantage of the integrability we present a procedure for obtaining the cumulant generating function of the probability distribution to transfer a fixed amount

K. Hamaya, T. Taniyama, Y. Yamazaki

We study magnetization reversal processes of in-plane magnetized (Ga,Mn)As epilayers with different hole concentrations in out-of-plane magnetic fields using magnetotransport measurements. A clear difference in the magnetization process is found in two separate samples with hole concentrations of 10^20 cm^-3 and 10^21 cm^-3 as the magnetization rotates from

J. H. Kim, W. K. Yeoh, M. J. Qin, X. Xu

We evaluated the doping effect of two types of multiwall carbon nanotube (CNT) with different aspect ratios on MgB2/Fe monofilament wires. Relationships between microstructure, magnetic critical current density (Jc), critical temperature (Tc), upper critical field (Hc2), and irreversibility field (Hirr) for pure and CNT doped wires were systematically studie

K. S. Glavatskiy, V. L. Kulinskii

We propose the description of the granular matter which is based on distribution of dry friction coefficients. Using such a concept and a simple one-dimensional packing of grains we solve the silo problem. The friction coefficients at contacts are determined both by geometry of packing configuration and the stress distribution in a medium. Within such an app

Keiji Yada, Hiroshi Kontani

To study the possible mechanism of superconductivity in Na$_{0.35}$CoO$_2$, we examine the interaction between all the relevant optical phonons (breathing and shear phonons) and $t_{2g}(a_{1g}+e_g&#39;)$-electrons of Co-ions, and study the transition temperature for a s-wave superconductivity. The obtained $T_{\rm c}$ is very low when the $e_g&#39;$-valence-

Yair Shokef, Guy Bunin, Dov Levine

Exact theoretical results for the violation of time dependent fluctuation-dissipation relations in driven dissipative systems are presented. The ratio of correlation to delayed response in the stochastic model introduced in [Phys. Rev. Lett. 93, 240601 (2004)] is shown to depend on measurement time. The fluctuation temperature defined by this ratio differs b

O. Naaman, J. Aumentado

In time-domain measurements of a Poisson two-level system, the observed transition rates are always smaller than those of the actual system, a general consequence of finite measurement bandwidth in an experiment. This underestimation of the rates is significant even when the measurement and detection apparatus is ten times faster than the process under study

J. Bürki, C. A. Stafford, D. L. Stein

In a recent Letter [Appl. Phys. Lett. 87, 103104 (2005)], Yoshida et al. report that nonlinearities in current-voltage curves of gold quantum point contacts occur as a result of a shortening of the distance between electrodes at finite bias, presumably due to thermal expansion. For short wires, the electrode displacement induces a thickening of the wire, as

Geraint F. Lewis, Rodrigo Gil-Merino

The magnification induced by gravitational microlensing is sensitive to the size of a source relative to the Einstein radius, the natural microlensing scale length. This paper investigates the effect of source size in the case where the microlensing masses are distributed with a bimodal mass function, with solar mass stars representing the normal stellar mas

Marc S. Seigar, James S. Bullock, Aaron J. Barth, Luis C. Ho

We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well-correlated with the rate of shear (S) in disk galaxy rotation curves, by using a much larger sample (51 galaxies) than used previously (17 galaxies). We use this correlation to argue that imaging

Paula Benaglia

Massive, early-type stars deposit energy and momentum in the interstellar medium through dense, supersonic winds. These objects are one of the most important sources of ionising radiation and chemical enrichment in the Galaxy. The physical conditions in the winds give rise to thermal and non-thermal emission, detectable from radio to gamma rays. In this repo

Tijana Prodanovic, Brian D. Fields, John F. Beacom

Pion decay gamma rays have long been recognized as a unique signature of hadronic cosmic rays and their interactions with the interstellar medium. We present a model-independent way of constraining this signal with observations of the Galactic Plane in diffuse gamma rays. We combine detections by the EGRET instrument at GeV energies and the Milagro Cherenkov

Daniel De Marco, Pasquale Blasi, Angela V. Olinto

We study the small scale anisotropy signal expected at the Pierre Auger Observatory in the next 1, 5, 10, and 15 years of operation, from sources of ultra-high energy (UHE) protons. We numerically propagate UHE protons over cosmological distances using an injection spectrum and normalization that fits current data up to $\sim 10^{20}\eV$. We characterize pos

A. Sajina, D. Scott, M. Dennefeld, H. Dole

Galaxies selected at 170um by the ISO FIRBACK survey represent the brightest \~10% of the Cosmic Infrared Background. Examining their nature in detail is therefore crucial for constraining models of galaxy evolution. Here we combine Spitzer archival data with previous near-IR, far-IR, and sub-mm observations of a representative sample of 22 FIRBACK galaxies

F. Siddhartha Guzman, L. Arturo Urena-Lopez

Equilibrium configurations for a self-gravitating scalar field with self-interaction are constructed. The corresponding Schrödinger-Poisson (SP) system is solved using finite differences assuming spherical symmetry. It is shown that equilibrium configurations of the SP system are late-time attractor solutions for initially quite arbitrary density profiles, w

E. M. Geijo, S. Torres, J. Isern, E. Garcia-Berro

Over the years, several methods have been proposed to compute galaxy luminosity functions, from the most simple ones -counting sample objects inside a given volume- to very sophisticated ones -like the C- method, the STY method or the Choloniewski method, among others. However, only the V/Vmax method is usually employed in computing the white dwarf luminosit

S. A. Paron, E. Reynoso, C. Purcell, G. Dubner

We report on the detection of HCO+ and 12CO emission in the rotational transition J=1-0 in the vicinity of the shock front at the southern border of the supernova remnant RCW 103, where previous infrared observations suggest an interaction with a molecular cloud. The observations were carried out with the Australian Millimeter Radiotelescope at Mopra. We obs

S. Hubrig, P. North, M. Schoeller, G. Mathys

To properly understand the physics of Ap and Bp stars it is particularly important to identify the origin of their magnetic fields. For that, an accurate knowledge of the evolutionary state of stars that have a measured magnetic field is an important diagnostic. Previous results based on a small and possibly biased sample suggest that the distribution of mag

G. C. Sloan, K. E. Kraemer, M. Matsuura, P. R. Wood

We have observed a sample of 36 objects in the Small Magellanic Cloud (SMC) with the Infrared Spectrometer on the Spitzer Space Telescope. Nineteen of these sources are carbon stars. An examination of the near- and mid-infrared photometry shows that the carbon-rich and oxygen-rich dust sources follow two easily separated sequences. A comparison of the spectr

Habib G. Khosroshahi, Ben J. Maughan, Trevor J. Ponman, Laurence R. Jones

We present a detailed X-ray and optical study of a distant fossil system RX J1416.4+2315 (z=0.13), combining Chandra and XMM-Newton observations, optical photometry and spectroscopy. X-ray emitting hot gas imaged by both the Chandra and XMM-Newton shows a globally relaxed spatial distribution, supporting the idea that fossil groups are old galaxy systems wit

S. Andreon

Using one of the deepest datasets available, we determine that the red sequence of the massive cluster MS1054-0321 at z=0.831 is well populated at all studied magnitudes, showing no deficit of faint (down to M^*+3.5) red galaxies: the faint end of the colour-magnitude relation is neither empty nor underpopulated. The effect is quantified by the computation o

D. Ward-Thompson, D. Nutter, S. Bontemps, A. Whitworth

We present observations taken with SCUBA on the JCMT of the Horsehead Nebula in Orion (B33), at wavelengths of 450 and 850 \mum. We see bright emission from that part of the cloud associated with the photon-dominated region (PDR) at the `top&#39; of the horse&#39;s head, which we label B33-SMM1. We characterise the physical parameters of the extended dust re

G. Mangano

I review some of the basic information on the Cosmic Neutrino Background momentum distribution. In particular, I discuss how present data from several cosmological observables such as Big Bang Nucleosynthesis, Cosmic Microwave Background and Large Scale Structure power spectrum constrain possible deviations from a standard Fermi-Dirac thermal distribution.

T. Kronberger, M. P. Leubner, E. van Kampen

Density profiles of simulated galaxy cluster-sized dark matter haloes are analysed in the context of a recently introduced nonextensive theory of dark matter and gas density distributions. Nonextensive statistics accounts for long-range interactions in gravitationally coupled systems and is derived from the fundamental concept of entropy generalisation. The

Ya. Pavlyuchenkov, D. Wiebe, R. Launhardt, Th. Henning

We present a detailed theoretical study of the isolated Bok globule CB17 (L1389) based on spectral maps of CS, HCO$^+$, C$^{18}$O, C$^{34}$S, and H$^{13}$CO$^+$ lines. A phenomenological model of prestellar core evolution, a time-dependent chemical model, and a radiative transfer simulation for molecular lines are combined to reconstruct the chemical and kin

Jiren Liu, Priya Jamkhedkar, Wei Zheng, Long-Long Feng

Using cosmological hydrodynamic simulations of the LCDM model, we present a comparison between the simulation sample and real data sample of HI and HeII Lyαtransmitted flux in the absorption spectra of the QSO HE2347-4342. The LCDM model is successful in simultaneously explaining the statistical features of both HI and HeII Lyαtransmitted flux. It includes:

X. P. You, J. L. Han

We update the systematic studies of circular polarization in integrated pulse profiles by Han et al (1998). Data of circular polarization profiles are compiled. Sense reversals can occur in core or cone components, or near the intersection between components. The correlation between the sense of circular polarization and the sense of position angle variation

Emily M. Levesque, Philip Massey, K. A. G. Olsen, Bertrand Plez

We use the MARCS stellar atmosphere to derive the physical properties of 36 red supergiants (RSGs) in the LMC, and 39 RSGs in the SMC using moderate-resolution optical spectrophotometry (4000-9000A) and broad-band colors (V-R, V-K). The results from the dereddened V-R colors are in good agreement with those derived from the spectrophotometry, but the deredde

Xiuxiong Chen, Weiyong He

We first give a precise statement on the short time existence of the Calabi flow and prove a stability result: any metric near a constant scalar curvature metric will flow to this cscK metric exponentially fast. Secondly, we prove that a compactness theorem in space of the kahler metrics given unifrom Ricci bound and potential bound. As an application, we pr

Peter Collas, David Klein

We use Fermi coordinates to calculate the canonical partition function for an ideal gas in a circular geodesic orbit in Schwarzschild spacetime. To test the validity of the results we prove theorems for limiting cases. We recover the Newtonian gas law subject only to tidal forces in the Newtonian limit. Additionally we recover the special relativistic gas la

Lutz Mattner, Bero Roos

We give a shorter proof of Kanter&#39;s (1976) sharp Bessel function bound for concentrations of sums of independent symmetric random vectors. We provide sharp upper bounds for the sum of modified Bessel functions $I_0(x)+I_1(x)$, which might be of independent interest. Corollaries improve concentration or smoothness bounds for sums of independent random var

Nils M. Bezares-Roder, Hemwati Nandan

The foundations of the mass generation mechanism of particles are reviewed. The Spontaneous Symmetry Breaking (SSB) process within the standard model (SM) and the minimal supersymmetric standard model (MSSM) is used to explore the present status of the Higgs Mechanism along with the constraints in detecting the Higgs particles in experiments. The possible ex

Rudolph C. Hwa, C. B. Yang

The production of pions and protons in the $p_T$ range between 10 and 20 GeV/c for Pb+Pb collisions at LHC is studied in the recombination model. It is shown that the dominant mechanism for hadronization is the recombination of shower partons from neighboring jets when the jet density is high. Protons are more copiously produced than pions in that $p_T$ rang

B. L. Voronov, D. M. Gitman, I. V. Tyutin

Considerable attention has been recently focused on quantum-mechanical systems with boundaries and/or singular potentials for which the construction of physical observables as self-adjoint (s.a.) operators is a nontrivial problem. We present a comparative review of various methods of specifying ordinary s.a. differential operators generated by formally s.a.

Dirk Grupe, Karen M. Leighly, Stefanie Komossa, Patricia Schady

We report on Swift observations of the Narrow-Line Seyfert 1 galaxy (NLS1) RX J0148.3--2758. It was observed for 41.6 ks in 2005 May and for 15.8 ks in 2005 December. On short as well as on long timescales RX J0148.3--2758 is a highly variable source. It doubles its X-ray flux within 18-25 ks. The observation of 2005 December 09, which had a flux 4 times low

Hiranya Peiris, Richard Easther

We introduce a new method for applying an inflationary prior to a cosmological dataset that includes relations between observables at arbitrary order in the slow roll expansion. The process is based on the inflationary flow equations, and the slow roll parameters appear explicitly in the cosmological parameter set. We contrast our method to other ways of imp

John C. Baez, Derek K. Wise, Alissa S. Crans

After a review of exotic statistics for point particles in 3d BF theory, and especially 3d quantum gravity, we show that string-like defects in 4d BF theory obey exotic statistics governed by the &#39;loop braid group&#39;. This group has a set of generators that switch two strings just as one would normally switch point particles, but also a set of generato

S. L. Dubovsky, S. M. Sibiryakov

We study the effect of spontaneous breaking of Lorentz invariance on black hole thermodynamics. We consider a scenario where Lorentz symmetry breaking manifests itself by the difference of maximal velocities attainable by particles of different species in a preferred reference frame. The Lorentz breaking sector is represented by the ghost condensate. We find