March 2010 arXiv papers — page 27

M. Scala, B. Militello, A. Messina, N. V. Vitanov

A master equation approach to the study of environmental effects in the adiabatic population transfer in three-state systems is presented. A systematic comparison with the non-Hermitian Hamiltonian approach [N. V. Vitanov and S. Stenholm, Phys. Rev. A {\bf 56}, 1463 (1997)] shows that in the weak coupling limit the two treatments lead to essentially the same

S. V. Kalenskii, L. E. B. Johansson, P. Bergman, S. Kurtz

A survey of young bipolar outflows in regions of low-to-intermediate-mass star formation has been carried out in two class I methanol maser transitions: 7_0-6_1A+ at 44 GHz and 4_{-1}-3_0E at 36 GHz. We detected narrow features towards NGC 1333I2A, NGC 1333I4A, HH25MMS, and L1157 at 44 GHz, and towards NGC 2023 at 36 GHz. Flux densities of the lines detected

Charles Bonatto, Eduardo Bica

We investigate the nature and possible evolution of the young Galactic star clusters Collinder 197 (Cr 197) and vdB 92. The colour-magnitude diagrams (CMDs) are basically characterised by a poorly-populated MS and a dominant fraction ($\ga75%$) of PMS stars, and the combined MS and PMS CMD morphology in both clusters consistently constrains the age to within

Wladimir Neves, Viatcheslav Priimenko, Mikhail Vishnevskii

We prove the well-posedness of the Cauchy problem on torus to an eletromagnetoelastic system. The physical model consists of three coupled partial differential equations, one of them is a hyperbolic equation describing the elastic medium and two other ones form a parabolic system, which comes from Maxwell's equations. Experimental measurements suggest th

D. Fedchenko, N. Tarkhanov

We study the Cauchy problem for the Laplace equation in a cylindrical domain with data on a part of it's boundary which is a cross-section of the cylinder. On reducing the problem to the Cauchy problem for the wave equation in a complex domain and using hyperbolic theory we obtain explicit formulas for the solution, thus developing the classical approach

Dan Popovici

Given a (smooth) complex analytic family of compact complex manifolds, we prove that the central fibre must be Moishezon if the other fibres are Moishezon. Using a "strongly Gauduchon metric" on the central fibre whose existence was proved in our previous work on limits of projective manifolds, we show that the irreducible components of the relative

A. B. Hopkins, F. H. Stillinger, S. Torquato

The densest local packing (DLP) problem in d-dimensional Euclidean space Rd involves the placement of N nonoverlapping spheres of unit diameter near an additional fixed unit-diameter sphere such that the greatest distance from the center of the fixed sphere to the centers of any of the N surrounding spheres is minimized. Solutions to the DLP problem are rele

Th. Rivinius, Th. Szeifert, L. Barrera, R. H. D. Townsend

The B2Vn star HR 7355 is found to be a He-rich magnetic star. Spectropolarimetric data were obtained with FORS1 at UT2 on Paranal observatory to measure the disk-averaged longitudinal magnetic field at various phases of the presumed 0.52 d cycle. A variable magnetic field with strengths between B_z = -2200 and +3200G was found, with confidence limits of 100

Sergey Simonov

We consider self-adjoint unbounded Jacobi matrices with diagonal q_n=n and weights λ_n=c_n n, where c_n is a 2-periodical sequence of real numbers. The parameter space is decomposed into several separate regions, where the spectrum is either purely absolutely continuous or discrete. This constitutes an example of the spectral phase transition of the first or

Sergey Simonov

Small perturbations of the Jacobi matrix with weights \sqrt n and zero diagonal are considered. A formula relating the asymptotics of polynomials of the first kind to the spectral density is obtained, which is analogue of the classical Weyl-Titchmarsh formula for the Schroedinger operator on the half-line with summable potential. Additionally a base of gener

K. V. I. Saputra, G. R. W. Quispel, L. van Veen

In this paper we developed an integrating factor matrix method to derive conditions for the existence of first integrals. We use this novel method to obtain first integrals, along with the conditions for their existence, for two and three dimensional Lotka-Volterra systems with constant terms. The results are compared to previous results obtained by other me

J. J. Cooper, D. W. Hallwood, J. A. Dunningham

The advent of increasingly precise gyroscopes has played a key role in the technological development of navigation systems. Ring-laser and fibre-optic gyroscopes, for example, are widely used in modern inertial guidance systems and rely on the interference of unentangled photons to measure mechanical rotation. The sensitivity of these devices scales with the

F. Gargiulo, S. Huet

We recently proposed a model coupling the evolution of the opinions of the individual with the local network topology. The opinion dynamics is based on the Bounded Confidence model. The social networks is based on a group concept where each individual is totally connected to the members of its group and is linked to the individuals of the other groups with a

Xavier Carvajal, Wladimir Neves

Applying an Abstract Interpolation Lemma, we can show persistence of solutions of the initial value problem to higher order nonlinear Schrödinger equation, also called Airy-Schrödinger equation, in weighted Sobolev spaces $\mathcal{X}^{2,θ}$, for $0 \le θ\le 1$.

Eric Fossat, Eric Aristidi, Karim Agabi, Erick Bondoux

Context: The winter seeing at Concordia is essentially bimodal, excellent or quite poor, with relative proportions that depend on altitude above the snow surface. This paper studies the temporal behavior of the good seeing sequences. Aims: An efficient exploitation of extremely good seeing with an adaptive optics system needs long integrations. It is then im

Marcel Nutz

We consider the economic problem of optimal consumption and investment with power utility. We study the optimal strategy as the relative risk aversion tends to infinity or to one. The convergence of the optimal consumption is obtained for general semimartingale models while the convergence of the optimal trading strategy is obtained for continuous models. Th

Andrea Carbone, Gianluca Coló, Angela Bracco, Li-Gang Cao

Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the Pygmy Dipole Resonance (PDR) in 68Ni and 132Sn have been investigated by using different Random Phase Approximation (RPA) models for the dipole response, based on a representative set of Skyrme effective

C. Faugeras, B. Faugeras, M. Orlita, M. Potemski

Local laser excitation and temperature readout from the intensity ratio of Stokes to anti-Stokes Raman scattering signals are employed to study the thermal properties of a large graphene membrane. The concluded value of the heat conductivity coefficient κ~ 600 W/m \cdot K is smaller than previously reported but still validates the conclusion that graphene is

O. Costin, L. Dupaigne

We calculate the full asymptotic expansion of boundary blow-up solutions, for any nonlinearity f. Our approach enables us to state sharp qualitative results regarding uniqueness and ra-dial symmetry of solutions, as well as a characterization of nonlinearities for which the blow-up rate is universal. Lastly, we study in more detail the standard nonlinearitie

Steffen Klassert, Daniel Lenz, Peter Stollmann

We study measures on the real line and present various versions of what it means for such a measure to take only finitely many values. We then study perturbations of the Laplacian by such measures. Using Kotani-Remling theory, we show that the resulting operators have empty absolutely continuous spectrum if the measures are not periodic. When combined with G

Tobias Wassmann, Ari P. Seitsonen, A. Marco Saitta, Michele Lazzeri

We show that Clar's theory of the aromatic sextet is a simple and powerful tool to predict the stability, the π-electron distribution, the geometry, the electronic/magnetic structure of graphene nanoribbons with different hydrogen edge terminations. We use density functional theory to obtain the equilibrium atomic positions, simulated scanning tunneling

L. Mashonkina, N. Christlieb, P. S. Barklem, V. Hill

We report on a detailed abundance analysis of the strongly r-process enhanced giant star, HE 2327-5642 ([Fe/H] = -2.78, [r/Fe] = +0.99). Determination of stellar parameters and element abundances was based on analysis of high-quality VLT/UVES spectra. The surface gravity was calculated from the NLTE ionization balance between Fe I and Fe II, and Ca I and Ca

Tapio Pahikkala, Antti Airola, Tapio Salakoski

We propose a novel algorithm for greedy forward feature selection for regularized least-squares (RLS) regression and classification, also known as the least-squares support vector machine or ridge regression. The algorithm, which we call greedy RLS, starts from the empty feature set, and on each iteration adds the feature whose addition provides the best lea

Hung-Chin Jang

In wireless mesh networks such as WLAN (IEEE 802.11s) or WMAN (IEEE 802.11), each node should help to relay packets of neighboring nodes toward gateway using multi-hop routing mechanisms. Wireless mesh networks usually intensively deploy mesh nodes to deal with the problem of dead spot communication. However, the higher density of nodes deployed, the higher

Aditya Goel

Cryptography literally means "The art & science of secret writing & sending a message between two parties in such a way that its contents cannot be understood by someone other than the intended recipient". and Quantum word is related with "Light". Thus, Quantum Cryptography is a way of descripting any information in the form of quantum partic

Eaman Eftekhary

We show that if a positive integral surgery on a knot K inside a homology sphere X with Seifert genus g(K) results in an induced knot K_n in X_n(K)=Y which has simple Floer homology, we should have n>=2g(K). Moreover, if X is the standard sphere, the three-manifold Y is a L-space and the Heegaard Floer homology groups of K are determined by its Alexander pol

M. Ibrahim Moussa

In 1991, Gnanajothi [4] proved that the path graph P_n with n vertex and n-1 edge is odd graceful, and the cycle graph C_m with m vertex and m edges is odd graceful if and only if m even, she proved the cycle graph is not graceful if m odd. In this paper, firstly, we studied the graph C_m $\cup$ P_m when m = 4, 6,8,10 and then we proved that the graph C_ $\c

Saleh Ali K. Al-Omari, Putra Sumari

Mobile Ad Hoc Network (MANET) is a collection of two or more devices or nodes or terminals with wireless communications and networking capability that communicate with each other without the aid of any centralized administrator also the wireless nodes that can dynamically form a network to exchange information without using any existing fixed network infrast

S. Sumathy, B. Upendra Kumar

Secured communication in ad hoc wireless networks is primarily important, because the communication signals are openly available as they propagate through air and are more susceptible to attacks ranging from passive eavesdropping to active interfering. The lack of any central coordination and shared wireless medium makes them more vulnerable to attacks than

J. P. Coe, V. V. França, I. D'Amico

We investigate how well the one-dimensional Hubbard model describes the entanglement of particles trapped in a string of quantum wells. We calculate the average single-site entanglement for two particles interacting via a contact interaction and consider the effect of varying the interaction strength and the interwell distance. We compare the results with th

Fangwei Ye, Boris A. Malomed, Yingji He, Bambi Hu

We consider the impact of anisotropic nonlocality on the arrest of the collapse and stabilization of dipole-mode (DM) solitons in two-dimensional (2D) models of optical media with the diffusive nonlinearity. The nonlocal nonlinearity is made anisotropic through elliptic diffusivity. The medium becomes semi-local in the limit case of 1D diffusivity. Families

Neeraj Kumar, Manoj Kumar, R. B. Patel

There are many challenges when designing and deploying wireless sensor networks (WSNs). One of the key challenges is how to make full use of the limited energy to prolong the lifetime of the network, because energy is a valuable resource in WSNs. The status of energy consumption should be continuously monitored after network deployment. In this paper, we pro

Antongiulio Fornasiero

We study various notions of "tameness" for definably complete expansions of ordered fields. We mainly study structures with locally o-minimal open core, d-minimal structures, and dense pairs of d-minimal structures.

Bikramaditya Das, Susmita Das

For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and Rake-MMSE receivers is attempted in this paper. Further a detail study on Rake-MMSE time domain equalizers is carried out taking into account all the important parameters such as the effect of the number of Rake fingers and equalizer taps on the error rate perfor

Anand Gupta, Harsh Bedi, MS Don Bosco, Vinay Shashidhar

In recent times the cost of mobile communication has dropped significantly leading to a dramatic increase in mobile phone usage. The widespread usage has led mobiles to emerge as a strong alternative for other applications one of which is tracking. This has enabled law-enforcing agencies to detect overspeeding vehicles and organizations to keep track its emp

Hugh M. Hilden, Maria Teresa Lozano, Jose Maria Montesinos-Amilibia

The complete classification of representations of the Trefoil knot group G in S^{3} and SL(2,R), their affine deformations, and some geometric interpretations of the results, are given. Among other results, we also obtain the classification up to conjugacy of the non cyclic groups of affine Euclidean isometries generated by two isometries $μ$ and $ν$ such th

N. B. Prajapati, R. R. Agravat, M. I. Hasan

LA planning in cellular network is useful for minimizing location management cost in GSM network. In fact, size of LA can be optimized to create a balance between the LA update rate and expected paging rate within LA. To get optimal result for LA planning in cellular network simulated annealing algorithm is used. Simulated annealing give optimal results in a

A. X. C. N. Valente

We describe the fundamental difference between the nature of problems in traditional physics and that of many problems arising today in systems biology and other complex settings. The difference hinges on the much larger number of a priori plausible alternative laws for explaining the phenomena at hand in the latter case. An approach and a mathematical frame

Xiangqian Guo, Xuewen Liu, Kaiming Zhao

In this paper, it is proved that all irreducible Harish-Chandra modules over the $\Q$ Heisenberg-Virasoro algebra are of intermediate series (all weight spaces are 1-dimensional).

Reinhard Hoepfner, Yury Kutoyants

We consider a diffusion $(ξ_t)_{t\ge 0}$ whose drift involves a $T$-periodic signal. $T$ is fixed and known, whereas the signal depends on an unknown $d$-dimensional parameter $\vartheta\inΘ$. Assuming positive Harris recurrence of the grid chain $(ξ_{kT})_{k\in\mathbb{N}_0}$ and exploiting the periodic structure of the semigroup, we work with path segments

D. Salgado, J. L. Sanchez-Gomez, M. Ferrero

Exploiting the cone structure of the set of unnormalized mixed quantum states, we offer an approach to detect separability independently of the dimensions of the subsystems. We show that any mixed quantum state can be decomposed as $ρ=(1-λ)C_ρ+λE_ρ$, where $C_ρ$ is a separable matrix whose rank equals that of $ρ$ and the rank of $E_ρ$ is strictly lower than

N. C. Santos, E. Delgado Mena, G. Israelian, J. I. González-Hernández

It is well known that stars orbited by giant planets have higher abundances of heavy elements when compared with average field dwarfs. A number of studies have also addressed the possibility that light element abundances are different in these stars. In this paper we will review the present status of these studies. The most significant trends will be discuss

J. A. Acosta-Pulido, I. Agudo, R. Barrena, C. Ramos Almeida

Context. NRAO 150 is one of the brightest radio and mm AGN sources on the northern sky. It has been revealed as an interesting source where to study extreme relativistic jet phenomena. However, its cosmological distance has not been reported so far, because of its optical faintness produced by strong Galactic extinction. Aims. Aiming at measuring the redshif

F. L. Forgerini, W. Figueiredo

We study the surface growth generated by the random deposition of particles of different sizes. A model is proposed where the particles are aggregated on an initially flat surface, giving rise to a rough interface and a porous bulk. By using Monte Carlo simulations, a surface has grown by adding particles of different sizes, as well as identical particles on

Yury A. Kutoyants

We consider the problems of parameter estimation for several models of threshold ergodic diffusion processes in the asymptotics of large samples. These models are the direct continuous time analogues of the well-known in time series analysis threshold autoregressive (TAR) models. In such models the trend is switching when the observed process atteints some (

G. Voyatzis, T. Kotoulas, J. D. Hadjidemetriou

The continuation of resonant periodic orbits from the restricted to the general three body problem is studied in a systematic way. Starting from the Keplerian unperturbed system we obtain the resonant families of the circular restricted problem. Then we find all the families of the resonant elliptic restricted three body problem which bifurcate from the circ

Stanislav Shabala, James M. G. Mead, Paul Alexander

We develop an analytical model to follow the cosmological evolution of magnetic fields in disk galaxies. Our assumption is that fields are amplified from a small seed field via magnetohydrodynamical (MHD) turbulence. We further assume that this process is fast compared to other relevant timescales, and occurs principally in the cold disk gas. We follow the t

Rajkumar Kannan, Frederic Andres

Institutions all over the world are continuously exploring ways to use ICT in improving teaching and learning effectiveness. The use of course web pages, discussion groups, bulletin boards, and e-mails have shown considerable impact on teaching and learning in significant ways, across all disciplines. ELearning has emerged as an alternative to traditional cl

V. Pierrard, M. Lazar

Particle velocity distribution functions (VDF) in space plasmas often show non Maxwellian suprathermal tails decreasing as a power law of the velocity. Such distributions are well fitted by the so-called Kappa distribution. The presence of such distributions in different space plasmas suggests a universal mechanism for the creation of such suprathermal tails

Rajkumar Kannan

The basic classification techniques for organizing information are thesauri, taxonomy and faceted classification. Topic map is relatively a new entrant to this information space. Topic map standard describes how complex relationships between abstract concepts and real world resources can be represented using XML syntax. This paper explores how topic map inco

Polina Yu. Kotenkova

We describe the GIT-equivalence classes of linearized ample line bundles for the diagonal actions of the linear algebraic groups $SL(V)$ and $SO(V)$ on ${\mathbb{P}(V)^{m_1}\times \mathbb{P}(V^*)^{m_2}}$ and $\mathbb{P}(V)^m$ respectively.

Steffen Steinert, Florian Dolde, Philipp Neumann, Andrew Aird

We present a solid state magnetic field imaging technique using a two dimensional array of spins in diamond. The magnetic sensing spin array is made of nitrogen-vacancy (NV) centers created at shallow depths. Their optical response is used for measuring external magnetic fields in close proximity. Optically detected magnetic resonance (ODMR) is readout from

Adam Rudziński, Anna Tyszka-Zawadzka, Paweł Szczepański

In this paper, we present a simple, yet versatile, analytical model of one-dimensional photonic crystal (1D PC). In our theoretical model, we take into account direction of propagation and therefore do not neglect anisotropic nature of photonic crystals. We derive analytical expressions for mode spectrum and density of states in 1D photonic crystal. With tho

G. Rong, D. Zhang, J. C. Chen

We review the progress on experimental studies of the non-$D\bar D$ decays of the $ψ(3770)$ resonance. With the world average of the observed cross sections for $D\bar D$ production measured at 3.773 GeV by the MARK-I, MARK-II, BES and CLEO Collaborations, combined together with the cross section for $ψ(3770)$ production at its peak as well as initial state

Wei-Zhou Jiang

Effects of the density dependence of the nuclear symmetry energy on ground-state properties of superheavy nuclei are studied in the relativistic mean-field theory. It is found that the softening of the symmetry energy plays an important role in the empirical shift [Phys. Rev. C 67, 024309 (2003)] of spherical orbitals in superheavy nuclei. The calculation ba

Jae-Woo Lee

The Na-O anticorrelation seen in almost all globular clusters ever studied using high-resolution spectroscopy is now generally explained by the primordial pollution from the first generation of the intermediate-mass asymptotic giant branch stars to the proto-stellar clouds of the second generation of stars. However, the primordial pollution scenario may not

Eyal Lubetzky, Allan Sly

The cutoff phenomenon describes a sharp transition in the convergence of an ergodic finite Markov chain to equilibrium. Of particular interest is understanding this convergence for the simple random walk on a bounded-degree expander graph. The first example of a family of bounded-degree graphs where the random walk exhibits cutoff in total-variation was prov

C. W. Campbell, K. A. Dancer, P. S. Isaac, J. Links

The exact solution for the energy spectrum of a one-dimensional Hamiltonian with local two-site interactions and periodic boundary conditions is determined. The two-site Hamiltonians commute with the symmetry algebra given by the Drinfeld double D(D_3) of the dihedral group D_3. As such the model describes local interactions between non-Abelian anyons, with

Hikaru Kawamura

Brief review is given on recent numerical research of the ordering of two typical models of spin glasses (SGs), the three-dimensional (3D) Ising SG and the 3D Heisenberg SG models. Particular attention is paid to the questions of whether there is a thermodynamic transition in zero field, what are the associated critical properties, what is the nature of the

Patrick St-Amant

We will see that key concepts of number theory can be defined for arbitrary operations. We give a generalized distributivity for hyperoperations (usual arithmetic operations and operations going beyond exponentiation) and a generalization of the fundamental theorem of arithmetic for hyperoperations. We also give a generalized definition of the prime numbers

Fan Liu, Yu Gao

A tight linear correlation is established between the HCN line luminosity and the radio continuum (RC) luminosity for a sample of 65 galaxies (from Gao & Solomon's HCN survey), including normal spiral galaxies and luminous and ultraluminous infrared galaxies (LIRGs/ULIRGs). After analyzing the various correlations among the global far-infrared (FIR), RC,

Amir Kalev, Faqir C. Khanna, Michael Revzen

We identify a class of two-mode squeezed states which are parametrized by an angular variable ${0\leθ<2π}$ and a squeezing parameter $r$. We show that, for a large squeezing value, these states are either (almost) maximally entangled or product states depending on the value of $θ$. This peculiar behavior of entanglement is unique for infinite dimensional Hil

Yu Gao

Observations of intensely bright star-forming galaxies both close by and in the distant Universe at first glance seem to emphasize their similarity. But look a little closer, and differences emerge.

Xiaosheng Zhuang

Construction of Symmetric Complex Tight wavelet Frames from Pseudo Splines via Matrix Extension with Symmetry.

Eleanor G. Rieffel, Don Kimber, Jim Vaughan

Creating virtual models of real spaces and objects is cumbersome and time consuming. This paper focuses on the problem of geometric reconstruction from sparse data obtained from certain image-based modeling approaches. A number of elegant and simple-to-state problems arise concerning when the geometry can be reconstructed. We describe results and counterexam

R. Vogt

The charmonium yields are expected to be considerably suppressed if a deconfined medium is formed in high-energy heavy-ion collisions. In addition, the bottomonium states, with the possible exception of the Upsilon(1S) state, are also expected to be suppressed in heavy-ion collisions. However, in proton-nucleus collisions the quarkonium production cross sect

Y. Lipman, I. Daubechies

We use mass-transportation as a tool to compare surfaces (2-manifolds). In particular, we determine the &#34;similarity&#34; of two given surfaces by solving a mass-transportation problem between their conformal densities. This mass transportation problem differs from the standard case in that we require the solution to be invariant under global Möbius trans

Emmanuil H. Georgoulis, Omar Lakkis, Juha M. Virtanen

We derive energy-norm a posteriori error bounds for an Euler time-stepping method combined with various spatial discontinuous Galerkin schemes for linear parabolic problems. For accessibility, we address first the spatially semidiscrete case, and then move to the fully discrete scheme by introducing the implicit Euler time-stepping. All results are presented

Philipp Huber

Non-perturbative renormalization factors of bilinear quark operators are computed for the Chirally Improved lattice action with two dynamic quarks. The analysis is based on five different parameter sets with lattice size 12^3 x 24 and four parameter sets with lattice size 16^3 x 32. For the pseudoscalar renormalization factor the pion pole contribution is su

A. Schulz, A. De Martino, R. Egger

The electronic spin-orbit coupling in carbon nanotubes is strongly enhanced by the curvature of the tube surface and has important effects on the single-particle spectrum. Here, we include the full spin-orbit interaction in the formulation of the effective low-energy theory for interacting electrons in metallic single-wall carbon nanotubes and study its cons

Xiaoqin Guo, Ofer Zeitouni

We consider random walks in a balanced random environment in $\mathbb{Z}^d$, $d\geq 2$. We first prove an invariance principle (for $d\ge2$) and the transience of the random walks when $d\ge 3$ (recurrence when $d=2$) in an ergodic environment which is not uniformly elliptic but satisfies certain moment condition. Then, using percolation arguments, we show t

Michael Levin, Alexander P. McCauley, Alejandro W. Rodriguez, M. T. Homer Reid

We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic met

P. Cassata, O. Le Fevre, B. Garilli, D. Maccagni

Aims. The aim of this work is to study the contribution of the Ly-a emitters (LAE) to the star formation rate density (SFRD) of the Universe in the interval 2<z<6.6. Methods. We assembled a sample of 217 LAE from the Vimos-VLT Deep Survey (VVDS) with secure spectroscopic redshifts in the redshift range 2 < z < 6.62 and fluxes down to F=1.5x10^18 erg/s/cm^2.

Adam Muzzin, Pieter van Dokkum, Mariska Kriek, Ivo Labbe

We present an analysis of the far-infrared (FIR) spectral energy distributions (SEDs) of two massive K-selected galaxies at z = 2.122 and z = 2.024 detected at 24um, 70um, 160um by Spitzer, 250um, 350um, 500um by BLAST, and 870um by APEX. The large wavelength range of these observations and the availability of spectroscopic redshifts allow us to unambiguousl

G. Bonnoli, G. Ghisellini, L. Foschini, F. Tavecchio

In the first week of December 2009, the blazar 3C 454.3 became the brightest high energy source in the sky. Its photon flux reached and surpassed the level of 1e-5 ph/cm2/s above 100 MeV. The Swift satellite observed the source several times during the period of high gamma-ray flux, and we can construct really simultaneous spectral energy distributions (SED)

F. Tavecchio, G. Ghisellini, G. Bonnoli, G. Ghirlanda

We consider the 1.5 years Fermi Large Area Telescope light curves (E > 100 MeV) of the flat spectrum radio quasars 3C 454.3 and PKS 1510-089, which show high activity in this period of time. We characterise the duty cycle of the source by comparing the time spent by the sources at different flux levels. We consider in detail the light curves covering periods

Michael F. Barnsley, Andrew Vince

This paper contains four main results associated with an attractor of a projective iterated function system (IFS). The first theorem characterizes when a projective IFS has an attractor which avoids a hyperplane. The second theorem establishes that a projective IFS has at most one attractor. In the third theorem the classical duality between points and hyper

P. N. Bibikov

Three magnon bound states in all total spin sectors of general nonintegrable exactly rung-dimerized spin ladder are obtained by Bethe Ansatz. Basing on this result a dispersion law for $m$-magnon ($m>3$) bound states is conjectured. It is suggested that (depending on correlations between coupling constants) a behavior of the gas parameter (density of rung-tr

Xin Liu, Jenny E. Greene, Yue Shen, Michael A. Strauss

We report the discovery of four kpc-scale binary AGNs. These objects were originally selected from the Sloan Digital Sky Survey based on double-peaked [O III] 4959,5007 emission lines in their fiber spectra. The double peaks could result from pairing active supermassive black holes (SMBHs) in a galaxy merger, or could be due to bulk motions of narrow-line re

Brian C. Lacki, John F. Beacom

Primordial black holes (PBHs) are expected to accrete particle dark matter around them to form ultracompact minihalos (UCMHs), if the PBHs themselves are not most of the dark matter. We show that if most dark matter is a thermal relic, then the inner regions of UCMHs around PBHs are highly luminous sources of annihilation products. Flux constraints on gamma

Joel K. Fridriksson, Jeroen Homan, Rudy Wijnands, Mariano Mendez

We present Rossi X-Ray Timing Explorer and Swift observations made during the final three weeks of the 2006-2007 outburst of the super-Eddington neutron star (NS) transient XTE J1701-462, as well as Chandra and XMM-Newton observations covering the first ~800 days of the subsequent quiescent phase. The source transitioned quickly from active accretion to quie

Mark P. Hertzberg

Many classical scalar field theories possess remarkable solutions: coherently oscillating, localized clumps, known as oscillons. In many cases, the decay rate of classical small amplitude oscillons is known to be exponentially suppressed and so they are extremely long lived. In this work we compute the decay rate of quantized oscillons. We find it to be a po

Vladimir Georgescu

We give a description of the essential spectrum of a large class of operators on metric measure spaces in terms of their localizations at infinity. These operators are analogues of the elliptic operators on Euclidean spaces and our main result concerns the ideal structure of the $C^*$-algebra generated by them.

Marco Matone, Roberto Volpato

We explicitly show how the chiral superstring amplitudes can be obtained through factorisation of the higher genus chiral measure induced by suitable degenerations of Riemann surfaces. This powerful tool also allows to derive, at any genera, consistency relations involving the amplitudes and the measure. A key point concerns the choice of the local coordinat

Jun-Qing Xia, Matteo Viel, Carlo Baccigalupi, Gianfranco De Zotti

The NRAO VLA Sky Survey (NVSS) is the only dataset that allows an accurate determination of the auto-correlation function (ACF) on angular scales of several degrees for Active Galactic Nuclei (AGNs) at typical redshifts $z \simeq 1$. Surprisingly, the ACF is found to be positive on such large scales while, in the framework of the standard hierarchical cluste

N. P. H. Nesvadba, F. Boulanger, P. Salome, P. Guillard

We present a detailed analysis of the gas conditions in the H_2 luminous radio galaxy 3C326N at z~0.1, which has a low star formation rate (SFR~0.07 M_sun/yr) in spite of a gas surface density similar to those in starburst galaxies. Its star-formation efficiency is likely a factor ~20-30 lower than those of ordinary star-forming galaxies. Combining new IRAM

Stacy S. McGaugh, Joe Wolf

Local Group dwarf spheroidal satellite galaxies are the faintest extragalactic stellar systems known. We examine recent data for these objects in the plane of the Baryonic Tully-Fisher Relation (BTFR). While some dwarf spheroidals adhere to the BTFR, others deviate substantially. We examine the residuals from the BTFR and find that they are not random. The r

Dagny L. Looper, Subhanjoy Mohanty, John J. Bochanski, Adam J. Burgasser

TWA 30 is a remarkable young (7+/-3 Myr), low-mass (0.12+/-0.04 Msun), late-type star (M5+/-1) residing 42+/-2 pc away from the sun in the TW Hydrae Association. It shows strong outflow spectral signatures such as [S II], [O I], [O II], [O III], and Mg I], while exhibiting weak Halpha emission (-6.8+/-1.2 Angstroms). Emission lines of [S II] and [O I] are co

Claudio Cuevas, Miguel V. S. Frasson

We study some properties concerning the asymptotic behavior of solutions to nonautonomous retarded functional differential equations, depending on the knowledge of certain solutions of the associated generalized characteristic equation.

Alvaro Dominguez, Martin Oettel, S. Dietrich

We investigate the dynamics of colloids at a fluid interface driven by attractive capillary interactions. At submillimeter length scales, the capillary attraction is formally analogous to two-dimensional gravity. In particular it is a non-integrable interaction and it can be actually relevant for collective phenomena in spite of its weakness at the level of

John C. Baez, John Huerta

Starting from the four normed division algebras - the real numbers, complex numbers, quaternions and octonions - a systematic procedure gives a 3-cocycle on the Poincare Lie superalgebra in dimensions 3, 4, 6 and 10. A related procedure gives a 4-cocycle on the Poincare Lie superalgebra in dimensions 4, 5, 7 and 11. In general, an (n+1)-cocycle on a Lie supe

Craig A. Tracy, Harold Widom

In earlier work the authors obtained integral formulas for probabilities for a single particle in the asymmetric simple exclusion process. Here formulas are obtained for joint probabilities for several particles. In the case of a single particle the derivation here is simpler than the one in the earlier work for one of its main results.

Luis Seabra, Nic Shannon

Supersolid phases, in which a superfluid component coexists with conventional crystalline long range order, have recently attracted a great deal of attention in the context of both solid helium and quantum spin systems. Motivated by recent experiments on 2H-AgNiO$_2$, we study the magnetic phase diagram of a realistic three-dimensional spin model with single

A. Gasparyan, M. F. M. Lutz

We present and apply a novel scheme for studying photon- and pion-nucleon scattering beyond the threshold region. Partial-wave amplitudes for the $γ\, N$ and $πN$ states are obtained by an analytic extrapolation of subthreshold reaction amplitudes computed in chiral perturbation theory, where the constraints set by electromagnetic-gauge invariance, causality

Xin. Zhou, Fabrizio. Bocchino, Marco. Miceli, Salvatore. Orlando

The Cygnus Loop is interacting with a protrusion of the cavity wall in its eastern edge (the XA region), where the X-ray emission is very bright. The complexity of the environment and the non-linear physical processes of the shock-cloud interaction make the origin of the X-ray emission still not well understood. Our purpose is to understand the physical orig

Dmitry Vorotnikov

We study the flashing ratchet model of a Brownian motor, which consists in cyclical switching between the Fokker-Planck equation with an asymmetric ratchet-like potential and the pure diffusion equation. We show that the motor really performs unidirectional transport of mass, for proper parameters of the model, by analyzing the attractor of the problem and t

Ben Elias

The monoidal category of Soergel bimodules categorifies the Hecke algebra of a finite Weyl group. In the case of the symmetric group, morphisms in this category can be drawn as graphs in the plane. We define a quotient category, also given in terms of planar graphs, which categorifies the Temperley-Lieb algebra. Certain ideals appearing in this quotient are

Tim Johannsen, Dimitrios Psaltis

According to the no-hair theorem, an astrophysical black hole is uniquely described by only two quantities, the mass and the spin. In this series of papers, we investigate a framework for testing the no-hair theorem with observations of black holes in the electromagnetic spectrum. We formulate our approach in terms of a parametric spacetime which contains a

Thierry Champel, Serge Florens

We study theoretically the energy and spatially resolved local density of states (LDoS) in graphene at high perpendicular magnetic field. For this purpose, we extend from the Schrödinger to the Dirac case a semicoherent-state Green&#39;s-function formalism, devised to obtain in a quantitative way the lifting of the Landau-level degeneracy in the presence of

Philip Phillips, Mark Jarrell

In a recent Letter, Peets, et al. measured the x-ray intensity at the oxygen K-edge in overdoped La$_{2-x}$Sr$_x$CuO$_{4\pmδ}$ (LSCO) and Tl$_2$Ba$_2$CuO$_{6+δ}$. They claimed that, unlike the underdoped samples of LSCO and YBa$_2$Cu$_3$O$_x$ in which the integrated intensity increases at least linearly with doping, it saturates abruptly for a hole count exc