April 2010 arXiv papers — page 9

Bo, Tan, Laurent Massoulie

In this paper, we address the problem of content placement in peer-to-peer systems, with the objective of maximizing the utilization of peers' uplink bandwidth resources. We consider system performance under a many-user asymptotic. We distinguish two scenarios, namely "Distributed Server Networks" (DSN) for which requests are exogenous to the sys

M. El Baz, R. Fresneda, J. P. Gazeau, Y. Hassouni

By using a coherent state quantization of paragrassmann variables, operators are constructed in finite Hilbert spaces. We thus obtain in a straightforward way a matrix representation of the paragrassmann algebra. This algebra of finite matrices realizes a deformed Weyl-Heisenberg algebra. The study of mean values in coherent states of some of these operators

Cosma Rohilla Shalizi, Andrew C. Thomas

We consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual's covariates on their behavior or other measurable responses. We show that, generically, all of these are co

Jay D. Sau, Sumanta Tewari, S. Das Sarma

The list of quantum mechanical systems with non-Abelian statistics has recently been expanded by including generic spin-orbit-coupled semiconductors e.g., InAs) in proximity to a s-wave superconductor. Demonstration of the anyonic statistics using Majorana fermion interferometry in this system is a necessary first step towards topological quantum computation

Eli Gafni, Petr Kuznetsov

The condition of t-resilience stipulates that an n-process program is only obliged to make progress when at least n-t processes are correct. Put another way, the live sets, the collection of process sets such that progress is required if all the processes in one of these sets are correct, are all sets with at least n-t processes. We show that the ability of

Armand Brumer, Kenneth Kramer

A precise and testable modularity conjecture for rational abelian surfaces A with trivial endomorphisms, End_Q A = Z, is presented. It is consistent with our examples, our non-existence results and recent work of C. Poor and D. S. Yuen on weight 2 Siegel paramodular forms. We obtain fairly precise information on ell-division fields of semistable abelian vari

Weixing Shu, Na Fu, Xiaofang Lv, Hailu Luo

We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materials using the integral equation method (IEM). Based on the superposition principle, we use Hertz vector formulations of radiated fields to study the interaction of wave with matter. We derive in a new way the dispersion relation, Snell's law and re

V. R. Supradeepa, Ehsan Hamidi, Daniel E. Leaird, Andrew M. Weiner

We report new aspects of temporal dispersion in Fourier pulse shapers which contain spectral dispersers with a nonlinear frequency to space mapping. These effects are particularly important in high resolution operation since high resolution dispersers typically exhibit pronounced nonlinear angular dispersion over relatively small bandwidths. In this paper we

Ben Kain, Hong Y. Ling

If dark matter in the galactic halo is composed of bosons that form a Bose-Einstein condensate then it is likely that the rotation of the halo will lead to the nucleation of vortices. After a review of the Gross-Pitaevskii equation, the Thomas-Fermi approximation and vortices in general, we consider vortices in detail. We find strong bounds for the boson mas

Michael L. Falk, James S. Langer

Since the 1970's, theories of deformation and failure of amorphous, solidlike materials have started with models in which stress-driven, molecular rearrangements occur at localized flow defects via "shear transformations". This picture is the basis for the modern theory of "shear transformation zones" (STZ's), which is the focus of th

Jonathan Heras, Vico Pascual, Ana Romero, Julio Rubio

We present in this paper an evolution of a tool from a user interface for a concrete Computer Algebra system for Algebraic Topology (the Kenzo system), to a front-end allowing the interoperability among different sources for computation and deduction. The architecture allows the system not only to interface several systems, but also to make them cooperate in

Joseph West, Seth Ross, James Flesher

The analysis of a new "rolling release" mechanism is presented for three different "siege engine" designs. The range obtained with the rolling release is compared to the ranges obtained using the simpler "cup" and the proven "sling" release mechanisms. It is found that the rolling release is a significant improvement over the

Michael Barnsley, Andrew Vince

The eigenvalue problem for a linear function L centers on solving the eigen-equation Lx = rx. This paper generalizes the eigenvalue problem from a single linear function to an iterated function system F consisting of possibly an infinite number of linear or affine functions. The eigen-equation becomes F(X) = rX, where r>0 is real, X is a compact set, and F(X

Parthapratim Biswas, Arun K. Bhattacharya

We present a systematic study of the reconstruction of a non-negative function via maximum entropy approach utilizing the information contained in a finite number of moments of the function. For testing the efficacy of the approach, we reconstruct a set of functions using an iterative entropy optimization scheme, and study the convergence profile as the numb

Takahiro Misawa, Yukitoshi Motome

Effect of exchange anisotropy on the relaxation time of spin and vector chirality is studied for the antiferromagnetic classical Heisenberg model on the triangular lattice by using the nonequilibrium relaxation Monte Carlo method. We identify the Berezinskii-Kosterlitz-Thouless (BKT) transition and the chiral transition in a wide range of the anisotropy, eve

Hsien Shang, Alfred Glassgold, Wei-Chieh Lin, Chun-Fan J. Liu

The flux and line shape of the fine-structure transitions of \NeII\ and \NeIII\ at 12.8 and 15.55\,$μ$m and of the forbidden transitions of \OI\ $\lambda6300$ are calculated for young stellar objects with a range of mass-loss rates and X-ray luminosities using the X-wind model of jets and the associated wide-angle winds. For moderate and high accretion rates

Marco Castrillon Lopez, Jaime Munoz Masque

Let $C\to M$ be the bundle of connections of a principal bundle on $M$. The solutions to Hamilton-Cartan equations for a gauge-invariant Lagrangian density $Λ$ on $C$ satisfying a weak condition of regularity, are shown to admit an affine fibre-bundle structure over the set of solutions to Euler-Lagrange equations for $Λ$. This structure is also studied for

Markus J. Aschwanden, Anne W. Sandman

We investigate the recently quantified misalignment of $α_{mis} \approx 20^\circ-40^\circ$ between the 3-D geometry of stereoscopically triangulated coronal loops observed with STEREO/EUVI (in four active regions) and theoretical (potential or nonlinear force-free) magnetic field models extrapolated from photospheric magnetograms. We develop an efficient met

Dmitry Savostyanov, Eugene Tyrtyshnikov, Nikolay Zamarashkin

We propose a fast algorithm for mode rank truncation of the result of a bilinear operation on 3-tensors given in the Tucker or canonical form. If the arguments and the result have mode sizes n and mode ranks r, the computation costs $O(nr^3 + r^4)$. The algorithm is based on the cross approximation of Gram matrices, and the accuracy of the resulted Tucker ap

Ermanno F Borra

Conventional techniques that measure rapid time variations are inefficient or inadequate to discover and observe rapidly pulsating astronomical sources. It is therefore conceivable that there exist some classes of objects pulsating with extremely short periods that have not yet been discovered. This article starts from the fact that rapid flux variations gen

Pablo Piantanida, Shlomo Shamai

This paper investigates the capacity of compound state-dependent channels with non-causal state information available at only the transmitter. A new lower bound on the capacity of this class of channels is derived. This bound is shown to be tight for the special case of compound channels with stochastic degraded components, yielding the full characterization

L. F. Roberts, S. E. Woosley, R. D. Hoffman

Although they are but a small fraction of the mass ejected in core-collapse supernovae, neutrino-driven winds (NDWs) from nascent proto-neutron stars (PNSs) have the potential to contribute significantly to supernova nucleosynthesis. In previous works, the NDW has been implicated as a possible source of r-process and light p-process isotopes. In this paper w

Ashish Goel, Michael Kapralov, Sanjeev Khanna

A graph G'(V,E') is an \eps-sparsification of G for some \eps>0, if every (weighted) cut in G' is within (1\pm \eps) of the corresponding cut in G. A celebrated result of Benczur and Karger shows that for every undirected graph G, an \eps-sparsification with O(n\log n/\e^2) edges can be constructed in O(m\log^2n) time. Applications to modern mass

Mariano Chernicoff, J. Antonio Garcia, Alberto Guijosa

We study a `dressed' or `composite' quark in strongly-coupled N=4 super-Yang-Mills (SYM), making use of the AdS/CFT correspondence. We show that the standard string dynamics nicely captures the physics of the quark and its surrounding quantum non-Abelian field configuration, making it possible to derive a relativistic equation of motion that incorpor

Valérie Chanal, Chris Kimble

This paper looks at what happens when Communities of Practice are used as a tool for Knowledge Management. The original concept of a Community of Practice appears to have very little in common with the knowledge sharing communities found in Knowledge Management, which are based on a revised view of 'cultivated' communities. We examine the risks and b

Yu. Davydov

Let $X_i = {X_i(t), t \in T}$ be i.i.d. copies of a centered Gaussian process $X = {X(t), t \in T}$ with values in $\mathbb{R}^d$ defined on a separable metric space $T.$ It is supposed that $X$ is bounded. We consider the asymptotic behaviour of convex hulls $$ W_n = \conv\ {X_1(t), X_n(t), t \in T}$$ and show that with probability 1 $$ \lim_{n\to \infty} \

Gretchen L. H. Harris

I review what we have learned about the old stellar population of NGC 5128, the only large E galaxy close enough that we can currently observe individual stars as faint as the horizontal branch. Although its galaxy type is still a matter of debate for some, the uncertainties over distance are now largely resolved; comparison of five stellar distance indicato

Gian F. Giudice, Tao Han, Kai Wang, Lian-Tao Wang

Motivated by dark-matter considerations in supersymmetric theories, we investigate in a fairly model-independent way the detection at the LHC of nearly degenerate gauginos with mass differences between a few GeV and about 30 GeV. Due to the degeneracy of gaugino states, the conventional leptonic signals are likely lost. We first consider the leading signal f

Yam Ki Cheung, Ovidiu Daescu

We discuss two versions of the Fréchet distance problem in weighted planar subdivisions. In the first one, the distance between two points is the weighted length of the line segment joining the points. In the second one, the distance between two points is the length of the shortest path between the points. In both cases, we give algorithms for finding a (1+e

Anna M. M. Scaife, Bojan Nikolic, David A. Green, Rainer Beck

We report new cm-wave measurements at five frequencies between 15 and 18GHz of the continuum emission from the reportedly anomalous "region 4" of the nearby galaxy NGC6946. We find that the emission in this frequency range is significantly in excess of that measured at 8.5GHz, but has a spectrum from 15-18GHz consistent with optically thin free-free

C. Tortora, N. R. Napolitano, V. F. Cardone, M. Capaccioli

We analyze the color gradients (CGs) of ~50000 nearby SDSS galaxies. From synthetic spectral models based on a simplified star formation recipe, we derive the mean spectral properties, and explain the observed radial trends of the color as gradients of the stellar population age and metallicity (Z). The most massive ETGs (M_* > 10^{11} Msun) have shallow CGs

André-Nicolas Chené, Nicole St-Louis

We present the results of an intensive photometric and spectroscopic monitoring campaign of the WN4 Wolf-Rayet (WR) star WR1=HD4004. Our broadband V photometry covering a timespan of 91 days shows variability with a period of P=16.9$^{+0.6}_{-0.3}$ days. The same period is also found in our spectral data. The light-curve is non-sinusoidal with hints of a gra

Rupert L. Frank, Elliott H. Lieb, Robert Seiringer, Lawrence E. Thomas

We resolve several longstanding problems concerning the stability and the absence of multi-particle binding for N\geq 2 polarons. Fröhlich's 1937 polaron model describes non-relativistic particles interacting with a scalar quantized field with coupling \sqrtα, and with each other by Coulomb repulsion of strength U. We prove the following: (i) While there

Lucas Fresse

We define a variety of doubly indexed flags, this is a smooth, projective variety, and we describe it as an iterated over Grassmannian varieties. On the other hand, we consider the variety of partial flags which are stabilized by a given nilpotent endomorphism. We partition this variety into locally closed subvarieties which are vector bundles over varieties

R. J. Tackett, J. G. Parsons, S. M. Gaytan, L. E. Murr

Please refer to the abstract within the main body of the paper.

Natalia Silberstein

Codes which attain the sphere packing bound are called perfect codes. The most important metrics in coding theory on which perfect codes are defined are the Hamming metric and the Johnson metric. While for the Hamming metric all perfect codes over finite fields are known, in the Johnson metric it was conjectured by Delsarte in 1970's that there are no no

Reimar Finken, Steffen Kessler, Udo Seifert

This paper deals with flow-induced shape transitions of elastic capsules. The state of the art concerning both theory and experiments is briefly reviewed starting with dynamically induced small deformation of initially spherical capsules and the formation of wrinkles on polymerized membranes. Initially non-spherical capsules show tumbling and tank-treading m

David Bronfenbrenner, Matthew Bibee, Apurva Mehta

Understanding mechanical properties of materials requires not only complete determination of the three-dimensional response at a local scale, but also knowledge of the mode or the mechanism by which deformation takes place. Probing mechanical response at such a depth can be only achieved through a diffraction based method. In spite of this, diffraction based

Yoichi Ikeda, Hiroyuki Kamano, Toru Sato

We study the resonance energy of the strange dibaryons using two models with the energy-independent and energy-dependent potentials for the s-wave barKN interaction, both of which are derived by certain reductions from the leading order term of the effective chiral Lagrangian. These potential models produce rather different off-shell behaviors of the two-bod

Matthias Heymann

I study a class of action functionals on the space of unparameterized oriented rectifiable curves in R^n. The local action is a degenerate type of Finsler metric that may vanish in certain directions, thus allowing for curves with positive Euclidean length but zero action. Given two sets A_1 and A_2, I develop criteria under which there exists a minimum acti

Warwick de Launey, Daniel M. Gordon

Let $S(x)$ be the number of $n \leq x$ for which a Hadamard matrix of order $n$ exists. Hadamard's conjecture states that $S(x)$ is about $x/4$. From Paley's constructions of Hadamard matrices, we have that \[ S(x) = Ω(x/\log x). \] In a recent paper, the first author suggested that counting the products of orders of Paley matrices would result in a

Jen-Chieh Peng

Dimuon production has been studied in a series of fixed-target experiments at Fermilab during the last two decades. Highlights from these experiments, together with recent results from the Fermilab E866 experiment, are presented. Future prospects for studying the parton distributions in the nucleons and nuclei using dimuon production are also discussed.

Olga K. Sil'chenko, Aleksandrina A. Smirnova

Using the method of integral-field (3D) spectroscopy, we have investigated the kinematics and distribution of the gas and stars at the center of the early-type spiral galaxy with a medium scale bar NGC 7177 as well as the change in the mean age of the stellar population along the radius. A classical picture of radial gas inflow to the galactic center along t

M. Rybachuk*, A. Hertwig, M. Weise, M. Sahre

The synthesis of polymer-like amorphous carbon (a-C:H) thin-films by microwave excited collisional hydrocarbon plasma process is reported. Stable and highly aromatic a-C:H were obtained containing significant inclusions of poly(p-phenylene vinylene) (PPV). PPV confers universal optoelectronic properties to the synthesised material. That is a-C:H with tailor-

M. Rybachuk*, A. Hu, J. M. Bell

The resonant Raman scattering in N-IR - UV range from amorphous hydrogenated carbon (a-C:H) reveal inclusions of trans-polyacetylene (trans-(CH)x) chains with approximate length of up to 120 C=C units and inclusions of poly(p-phenylene vinylene) (PPV) polymer chains. The PPV is evidenced by a strong dispersive mode at ca. 1175 cm-1. It was found that the Ram

Mikhail Belkin, Kaushik Sinha

The question of polynomial learnability of probability distributions, particularly Gaussian mixture distributions, has recently received significant attention in theoretical computer science and machine learning. However, despite major progress, the general question of polynomial learnability of Gaussian mixture distributions still remained open. The current

P. Marsik, K. W. Kim, A. Dubroka, M. Roessle

We report muon spin rotation (muSR) and infrared (IR) spectroscopy experiments on underdoped BaFe1.89Co0.11As2 which show that bulk magnetism and superconductivity (SC) coexist and compete on the nanometer length scale. Our combined data reveal a bulk magnetic order, likely due to an incommensurate spin density wave (SDW), which develops below Tmag \approx 3

E. V. Gorelik, I. Titvinidze, W. Hofstetter, M. Snoek

We study the magnetic ordering transition for a system of harmonically trapped ultracold fermions with repulsive interactions in a cubic optical lattice, within a real-space extension of dynamical mean-field theory (DMFT). Using a quantum Monte Carlo impurity solver, we establish that antiferromagnetic correlations are signaled, at strong coupling, by an enh

R. B. Neufeld

The heavy ion program at the LHC will present unprecedented opportunities to probe hot QCD matter, that is, the quark gluon plasma (QGP). Among these exciting new probes are high energy partons associated with the production of a Z^0 boson, or Z^0 tagged jets. Once produced, Z^0 bosons are essentially unaffected by the strongly interacting medium produced in

Goutam Sheet, Manan Mehta, D. A. Dikin, S. Lee

The normal state properties of the recently discovered ferropnictide superconductors might hold the key to understanding their exotic superconductivity. Using point-contact spectroscopy we show that Andreev reflection between an epitaxial thin film of Ba(Fe$_{0.92}$Co$_{0.08}$)$_2$As$_2$ and a silver tip can be seen in the normal state of the film up to temp

Mohamed El Bachraoui

In this note we will give various exact formulas for functions on integer partitions including the functions $p(n)$ and $p(n,k)$ of the number of partitions of $n$ and the number of such partitions into exactly $k$ parts respectively. For instance, we shall prove that $$ p(n) = \sum_{d|n} \sum_{k=1}^{d} \sum_{i_0 =1}^{\lfloor d/k \rfloor} \sum_{i_1 =i_0}^{\l

M. Ausloos

A statistical physics study of punctuation effects on sentence lengths is presented for written texts: {\it Alice in wonderland} and {\it Through a looking glass}. The translation of the first text into esperanto is also considered as a test for the role of punctuation in defining a style, and for contrasting natural and artificial, but written, languages. S

Leon Ofman, Maxim Kramar

During the solar minimum STEREO observations show that the three-dimensional structure of the solar corona can be described well by a tilted bi-polar magnetic configuration. The slow solar wind is modeled using three-fluid model that includes heavy ions, such as He II and O VI. The model is initialized with dipole magnetic field and spherically symmetric den

Stefanos Dris, Costas Foudas, Karl Gill, Robert Grabit

The potential application of advanced digital communication schemes in a future upgrade of the CMS Tracker readout optical links is currently being investigated at CERN. We show experimentally that multi-Gbit/s data rates are possible over the current 40 MSamples/s analog optical links by employing techniques similar to those used in ADSL. The concept involv

George Deligiannidis, Sergey Utev

We present a Darboux-Wiener type lemma and apply it to obtain an exact asymptotic for the variance of the self-intersection of one and two-dimensional random walks. As a corollary, we obtain a central limit theorem for random walk in random scenery conjectured by Kesten and Spitzer in 1979.

G. P. Brandino, R. M. Konik, G. Mussardo

We study the energy level spacing of perturbed conformal minimal models in finite volume, considering perturbations of such models that are massive but not necessarily integrable. We compute their spectrum using a renormalization group improved truncated conformal spectrum approach. With this method we are able to study systems where more than 40000 states a

Richard Froese, David Hasler, Wolfgang Spitzer

We review a geometric approach to proving absolutely continuous (ac) spectrum for random and deterministic Schrödinger operators developed in \cite{FHS1,FHS2,FHS3,FHS4}. We study decaying potentials in one dimension and present a simplified proof of ac spectrum of the Anderson model on trees. The latter implies ac spectrum for a percolation model on trees. F

A. Thirouin, J. L. Ortiz, R. Duffard, P. Santos-Sanz

We present results of 6 years of observations, reduced and analyzed with the same tools in a systematic way. We report completely new data for 15 objects, for 5 objects we present a new analysis of previously published results plus additional data and for 9 objects we present a new analysis of data already published. Lightcurves, possible rotation periods an

Lei Ni, Yanyan Niu

In this paper we study the heat equation (of Hodge-Laplacian) deformation of $(p, p)$-forms on a Kähler manifold. After identifying the condition and establishing that the positivity of a $(p, p)$-form solution is preserved under such an invariant condition we prove the sharp differential Harnack (in the sense of Li-Yau-Hamilton) estimates for the positive s

Lucas Fresse

Let $u\in\mathrm{End}(\mathbb{C}^n)$ be nilpotent. The variety of $u$-stable complete flags is called the Springer fiber over $u$. Its irreducible components are parameterized by a set of standard Young tableaux. The Richardson (resp. Bala-Carter) components of Springer fibers correspond to the Richardson (resp. Bala-Carter) elements of the symmetric group,

A. M. Scarfone

By assuming an appropriate energy composition law between two systems governed by the same non-extensive entropy, we revisit the definitions of temperature and pressure, arising from the zeroth principle of thermodynamics, in a manner consistent with the thermostatistics structure of the theory. We show that the definitions of these quantities are sensitive

Burra G. Sidharth

Numerous observations and studies suggest that the universe has some sort of overall rotation. We consider this matter and provide a new angle.

Patrick K. S. Vaudrevange

A compactification of the E_8 x E_8 heterotic string on a Z_2 x Z_2 orbifold equipped with an additional freely acting involution is presented. This model reproduces the exact chiral MSSM spectrum with matter parity and a non-trivial Yukawa structure. The key ingredient is a freely acting Wilson line associated to the involution, breaking SU(5) to SU(3) x SU

Rahim Moosa

In this note a natural strengthening of internality motivated by complex geometry, being "Moishezon" to a set of types, is introduced. Under the hypothesis of Pillay's canonical base property, and using results of Chatzidakis, a criterion is given for when a finite U-rank stationary type that is internal to a nonmodular minimal type is in fact Mo

R. S. Caraça, M. Malheiro

In this work we study the electric charge effect on the cross section production of charged mini black holes (MBH) in accelerators. We analyze the charged MBH solution using the {\it fat brane} approximation in the context of the ADD model. The maximum charge-mass ratio condition for the existence of a horizon radius is discussed. We show that the electric c

Craig A. Sloane

We prove several Sobolev inequalities, which are then used to establish a fractional Hardy-Sobolev- Maz'ya inequality on the upper halfspace.

Jesús García-López, Carlos Marijuán

We introduce adequate concepts of expansion of a digraph to obtain a sequential construction of minimal strong digraphs. We characterize the class of minimal strong digraphs whose expansion preserves the property of minimality. We prove that every minimal strong digraph of order $n\geq 2$ is the expansion of a minimal strong digraph of order $n-1$ and we giv

Xueying Hou, Chenyang Yang

Base station (BS) cooperative transmission, also known as coordinated multi-point transmission (CoMP), is an effective way to avoid inter-cell interference in universal frequency reuse cellular systems. To gain the promised benefit, however, huge feedback overhead is in demand to gather the channel information. In this paper, we analyze the impact of channel

Matjaz Perc

We study the evolution of Slovenia's scientific collaboration network from 1960 till present with a yearly resolution. For each year the network was constructed from publication records of Slovene scientists, whereby two were connected if, up to the given year inclusive, they have coauthored at least one paper together. Starting with no more than 30 scie

Dorje C. Brody, Lane P. Hughston, Andrea Macrina

This paper presents an overview of information-based asset pricing. In this approach, an asset is defined by its cash-flow structure. The market is assumed to have access to "partial" information about future cash flows. Each cash flow is determined by a collection of independent market factors called X-factors. The market filtration is generated by

S. Capozziello, M. De Laurentis, I. De Martino, M. Formisano

Coalescing binary systems, consisting of two collapsed objects, are among the most promising sources of high frequency gravitational waves signals detectable, in principle, by ground-based interferometers. Binary systems of Neutron Star or Black Hole/Neutron Star mergers should also give rise to short Gamma Ray Bursts, a subclass of Gamma Ray Bursts. Short-h

Denis Parganlija, Francesco Giacosa, Dirk H. Rischke

We calculate low-energy meson decay processes and pion-pion scattering lengths in a globally chirally invariant two-flavour linear sigma model exploring the quark content of the scalar mesons f(0)(600) and a(0)(980), as well as f(0)(1370) and a(0)(1450). To this end, we investigate which one of these sets of fields is more likely to contain quark-antiquark s

Matthew A. Bershady, Marc A. W. Verheijen, Rob A. Swaters, David R. Andersen

We present a survey of the mass surface-density of spiral disks, motivated by outstanding uncertainties in rotation-curve decompositions. Our method exploits integral-field spectroscopy to measure stellar and gas kinematics in nearly face-on galaxies sampled at 515, 660, and 860 nm, using the custom-built SparsePak and PPak instruments. A two-tiered sample,

Emmanuel Abbe, Rethnakaran Pulikkoonattu

Over binary input channels, uniform distribution is a universal prior, in the sense that it allows to maximize the worst case mutual information over all binary input channels, ensuring at least 94.2% of the capacity. In this paper, we address a similar question, but with respect to a universal generalized linear decoder. We look for the best collection of f

A. Branschädel, E. Boulat, H. Saleur, P. Schmitteckert

By using two independent and complementary approaches, we compute exactly the shot noise in an out-of-equilibrium interacting impurity model, the Interacting Resonant Level model at its self-dual point. An analytical approach based on the Thermodynamical Bethe Ansatz allows to obtain the density matrix in the presence of a bias voltage, which in turn allows

Vincent Lucas, Jean-Jacques Pansiot, Dominique Grad, Benoît Hilt

The most efficient receiver-driven multicast congestion control protocols use dynamic channels. This means that each group has a cyclic rate variation with a continuously decreasing phase. Despite promising results in terms of fairness, using efficiently these dynamic groups could be a challenging task for application programmers. This paper presents a seque

D. Levi, M. A. Rodriguez

Following the usual definition of $λ$-symmetries of differential equations, we introduce the analogous concept for difference equations and apply it to some examples.

Vadim E. Levit, Eugen Mandrescu

The square of a graph G is the graph G^2 with the same vertex set as in G, and an edge of G^2 is joining two distinct vertices, whenever the distance between them in G is at most 2. G is a square-stable graph if it enjoys the property alpha(G)=alpha(G^2), where alpha(G) is the size of a maximum stable set in G. In this paper we show that G^2 is a Konig-Egerv

J. M. Landsberg, Laurent Manivel, Nicolas Ressayre

We determine set-theoretic defining equations for the variety of hypersurfaces of degree d in an N-dimensional complex vector space that have dual variety of dimension at most k. We apply these equations to the Mulmuley-Sohoni variety, the GL_{n^2} orbit closure of the determinant, showing it is an irreducible component of the variety of hypersurfaces of deg

Philippe Besnard, Marie-Odile Cordier, Yves Moinard

We define an inference system to capture explanations based on causal statements, using an ontology in the form of an IS-A hierarchy. We first introduce a simple logical language which makes it possible to express that a fact causes another fact and that a fact explains another fact. We present a set of formal inference patterns from causal statements to exp

Alexandre T. Baraviera, Joao Lopes Dias, Pedro Duarte

We study the geometry of the action of SL(2,R) on the projective line in order to present a new and simpler proof of the Herman-Avila-Bochi formula. This formula gives the average Lyapunov exponent of a class of 1-families of SL(2,R)-cocycles.

L. F. Miranda, R. Vázquez, M. A. Guerrero, C. B. Pereira

We have recently confirmed the planetary nebula (PN)nature of PM1-242, PM1-318 and PM1-322. Here we present high-resolution long-slit spectra of these three PNe in order to analyze their internal kinematics and to investigate their physical structure. PM1-242 is a tilted ring and not an elliptical PN as suggested by direct images. The object is probably rela

Juan Carlos Martinez, Lajos Soukup

Using Koszmider&#39;s strongly unbounded functions, we show the following consistency result: Suppose that $κ,λ$ are infinite cardinals such that $κ^{+++} \leq λ$, $κ^{<κ}=κ$ and $2^κ= κ^+$, and $η$ is an ordinal with $κ^+\leq η<κ^{++}$ and $cf(η) = κ^+$. Then, in some cardinal-preserving generic extension there is a superatomic Boolean algebra $B$ such that

Donald Yau

Hom-alternative and Hom-Jordan algebras are shown to give rise to Hom-Nambu algebras of arities 2^{k+1} + 1. The class of n-ary Hom-Maltsev algebras is studied. Multiplicative n-ary Hom-Nambu-Lie algebras are shown to be n-ary Hom-Maltsev algebras. Examples of ternary Hom-Maltsev algebras that are not ternary Hom-Nambu-Lie algebras are given. Ternary Hom-Mal

R. K. Fedorov

A logical approach to object recognition on image is proposed. The main idea of the approach is to perform the object recognition as a logical inference on a set of rules describing an object shape.

Nicholas A. Christakis, James H. Fowler

Current methods for the detection of contagious outbreaks give contemporaneous information about the course of an epidemic at best. Individuals at the center of a social network are likely to be infected sooner, on average, than those at the periphery. However, mapping a whole network to identify central individuals whom to monitor is typically very difficul

R. Guimera, M. Sales-Pardo

Network analysis is currently used in a myriad of contexts: from identifying potential drug targets to predicting the spread of epidemics and designing vaccination strategies, and from finding friends to uncovering criminal activity. Despite the promise of the network approach, the reliability of network data is a source of great concern in all fields where

A. A. Filin, A. Romanov, V. Baru, C. Hanhart

We demonstrate that in calculation, where unitarity constraints are properly imposed, the deeply bound hadronic molecules recently proposed by Close and Downum do not exist.

Frank Reidegeld

We investigate cohomogeneity-one metrics whose principal orbit is an Aloff-Wallach space SU(3)/U(1). In particular, we are interested in metrics whose holonomy is contained in Spin(7). Complete metrics of this kind which are not product metrics have exactly one singular orbit. We prove classification results for metrics on tubular neighborhoods of various si

Xuewen Long, Keqing Lu, Yuhong Zhang, Jianbang Guo

Based on the vector angular spectrum method and the stationary phase method and the fact that a circular aperture function can be expanded into a finite sum of complex Gaussian functions, the analytical vectorial structure of a four-petal Gaussian beam (FPGB) diffracted by a circular aperture is derived in the far field. The energy flux distributions and the

A. Branschädel, E. Boulat, H. Saleur, P. Schmitteckert

We present a method to determine the shot noise in quantum systems from knowledge of their time evolution - the latter being obtained using numerical simulation techniques. While our ultimate goal is the study of interacting systems, the main issues for the numerical determination of the noise do not depend on the interactions. To discuss them, we concentrat

P. Lorén-Aguilar, J. Isern, E. García-Berro

The collision of two white dwarfs is a quite frequent event in dense stellar systems, like globular clusters and galactic nuclei. In this paper we present the results of a set of simulations of the close encounters and collisions of two white dwarfs. We use an up- to-date smoothed particle hydrodynamics code that incorporates very detailed input physics and

Wojciech Roga, Mark Fannes, Karol Zyczkowski

The Holevo quantity provides an upper bound for the mutual information between the sender of a classical message encoded in quantum carriers and the receiver. Applying the strong sub-additivity of entropy we prove that the Holevo quantity associated with an initial state and a given quantum operation represented in its Kraus form is not larger than the excha

Azizollah Azizi, Mohammad Mohammadi

Solitary wave and soliton solutions of nonlinear equations are well known for physicists. A soliton is a solitary wave with some outstanding features which make it reasonable to be studied seriously in nonlinear systems. In fact most of the nonlinear systems which have solitary wave solutions, has no soliton solutions. To realize a solitary wave as a soliton

Takahiro Morimoto, Yshai Avishai, Hideo Aoki

Dynamical scaling analysis is theoretically performed for the ac (optical) Hall conductivity $σ_{xy}(\varepsilon_F,ω)$ as a function of Fermi energy $\varepsilon_F$ and frequency $ω$ for the two-dimensional electron gas and for graphene. In both systems, results based on exact diagonalization show that $σ_{xy}(\varepsilon_F,ω)$ displays a well-defined dynami

Lorenzo Zaninetti

Two new luminosity functions of galaxies can be built starting from three and four parameter generalized gamma distributions. In the astrophysical conversion, the number of parameters increases by one, due to the addition of the overall density of galaxies. A third new galaxy luminosity function is built starting from a three parameter generalized gamma dist

Boris Tomasik

It is explained why and how the fireball created in ultrarelativistic nuclear collisions can fragment when passing the phase transition. It can happen at the first-order phase transition but is not excluded even at high collision energies where the smooth crossover is present. Two potential observables sensitive to the appearance of fragmentation are reviewe

Filippo Caruso, Holger Kantz

We investigate the predictability of extreme events in a dissipative Olami-Feder-Christensen model on a small world topology. Due to the mechanism of self-organized criticality, it is impossible to predict the magnitude of the next event knowing previous ones, if the system has an infinite size. However, by exploiting the finite size effects, we show that pr

Zhi-Qing Zhang

In this paper, we calculate the branching ratios for B^0\to D_s^+π^-, B^+\to D_s^+π^0, B^0\to D_s^{*+}π^- and B^+\to D_s^{*+}π^0 decays in the perturbative QCD factorization approach. We find that the calculated branching ratios of these four decay channels agree well with the measured values and current experimental upper limit. In the numerical calculation

Olga V. Borovkova, Yaroslav V. Kartashov, Lluis Torner

We consider soliton dynamics and stability in a nonlinear lattice formed by alternating domains with focusing cubic and saturable nonlinearities. We find that in such lattices solitons centered on cubic domains may be stabilized even in two-dimensional geometries, in spite of their intrinsic catastrophic instability in the absence of the lattice. Solitons ce