Skip to main content
SHOW DETAILS
eye
Title
Date Archived
Creator
Arxiv.org
by Kun Tian; Dewen Xiong; Zhongxing Ye
texts

eye 65

favorite 0

comment 0

In this paper, we assume that the filtration $\bb F$ is generated by a $d$-dimensional Brownian motion $W=(W_1,\cdots,W_d)'$ as well as an integer-valued random measure $\mu(du,dy)$. The random variable $\ttau$ is the default time and $L$ is the default loss. Let $\mathbb G=\{\scr G_t;t\geq 0\}$ be the progressive enlargement of $\bb F$ by $(\ttau,L)$, i.e, $\bb G$ is the smallest filtration including $\bb F$ such that $\ttau$ is a $\bb G$-stopping time and $L$ is $\scr G_\ttau$-measurable. We...
Topics: Mathematics, Probability
Source: http://arxiv.org/abs/1301.1119
Arxiv.org
by Mami Machida; Kenji E. Nakamura; Takahiro Kudoh; Takuya Akahori; Sofue Yoshiaki; Ryoji Matsumoto
texts

eye 75

favorite 0

comment 0

We carried out global three-dimensional magneto-hydrodynamic simulations of dynamo activities in galactic gaseous disks without assuming equatorial symmetry. Numerical results indicate the growth of azimuthal magnetic fields non-symmetric to the equatorial plane. As magneto-rotational instability (MRI) grows, the mean strength of magnetic fields is amplified until the magnetic pressure becomes as large as 10% of the gas pressure. When the local plasma $\beta$ ($ = p_{\rm gas}/p_{\rm mag}$)...
Topics: Astrophysics of Galaxies, Astrophysics
Source: http://arxiv.org/abs/1301.1414
Arxiv.org
texts

eye 104

favorite 0

comment 0

This paper studies a Stieltjes-type moment problem defined by the generalized lognormal distribution, a heavy-tailed distribution with applications in economics, finance and related fields. It arises as the distribution of the exponential of a random variable following a generalized error distribution, and hence figures prominently in the EGARCH model of asset price volatility. Compared to the classical lognormal distribution it has an additional shape parameter. It emerges that moment...
Topics: Mathematics, Other Statistics, Statistics, Probability
Source: http://arxiv.org/abs/1301.1277
Arxiv.org
by Paulo Shakarian; Gerardo I. Simari; Robert Schroeder
texts

eye 51

favorite 0

comment 0

The modeling of cascade processes in multi-agent systems in the form of complex networks has in recent years become an important topic of study due to its many applications: the adoption of commercial products, spread of disease, the diffusion of an idea, etc. In this paper, we begin by identifying a desiderata of seven properties that a framework for modeling such processes should satisfy: the ability to represent attributes of both nodes and edges, an explicit representation of time, the...
Topics: Multiagent Systems, Logic in Computer Science, Artificial Intelligence, Computing Research...
Source: http://arxiv.org/abs/1301.0302
Arxiv.org
texts

eye 49

favorite 0

comment 0

We find the height of the third fission barrier $B_{III}$ and energy of the third minimum $E_{III}$ in $^{232}$Th using the macroscopic - microscopic model, very well tested in this region of nuclei. For the first time it is done on an 8-dimensional deformation hypercube. The dipole distortion is included among the shape variables to assure that no important shapes are missed. The saddle point is found on a lattice containing more than 50 million points by the immersion water flow (IWF) method....
Topic: Nuclear Theory
Source: http://arxiv.org/abs/1301.0713
Arxiv.org
by Terrence Adams
texts

eye 85

favorite 0

comment 0

A technique is presented for multiplexing two ergodic measure preserving transformations together to derive a third limiting transformation. This technique is used to settle a question regarding rigidity of weak mixing transformations. Namely, given any rigidity sequence for an ergodic measure preserving transformation, there exists a weak mixing transformation which is rigid along the same sequence. This establishes a wide range of rigidity sequences for weakly mixing dynamical systems.
Topics: Mathematics, Dynamical Systems
Source: http://arxiv.org/abs/1301.0791
Arxiv.org
by Michael Mikucki; Y. C. Zhou
texts

eye 67

favorite 0

comment 0

Simulating protein-membrane interactions is an important and dynamic area of research. A proper definition of electrostatic forces on membrane surfaces is necessary for developing electromechanical models of protein-membrane interactions. Here we modeled the bilayer membrane as a continuum with general continuous distributions of lipids charges on membrane surfaces. A new electrostatic potential energy functional was then defined for this solvated protein-membrane system. We investigated the...
Topics: Mathematics, Quantitative Biology, Biomolecules, Analysis of PDEs
Source: http://arxiv.org/abs/1301.1104
Arxiv.org
texts

eye 41

favorite 0

comment 0

We study the existence of non-collision periodic solutions with Newtonian potentials for the following planar restricted 4-body problems: Assume that the given positive masses $m_{1},m_{2},m_{3}$ in a Lagrange configuration move in circular obits around their center of masses, the sufficiently small mass moves around some body. Using variational minimizing methods, we prove the existence of minimizers for the Lagrangian action on anti-T/2 symmetric loop spaces. Moreover, we prove the minimizers...
Topics: Mathematical Physics, Mathematics
Source: http://arxiv.org/abs/1301.0767
Arxiv.org
by Andrey Soldatenkov; Misha Verbitsky
texts

eye 125

favorite 0

comment 0

A hypercomplex manifold is a manifold equipped with a triple of complex structures satisfying the quaternionic relations. A holomorphic Lagrangian variety on a hypercomplex manifold with trivial canonical bundle is a holomorphic subvariety which is calibrated by a form associated with the holomorphic volume form; this notion is a generalization of the usual holomorphic Lagrangian subvarieties known in hyperkaehler geometry. An HKT (hyperkaehler with torsion) metric on a hypercomplex manifold is...
Topics: Mathematics, Differential Geometry, Algebraic Geometry
Source: http://arxiv.org/abs/1301.0175
Arxiv.org
by A. Aleksejevs; S. Barkanova
texts

eye 48

favorite 0

comment 0

Compton scattering offers a unique opportunity to study the dynamical structure of hadrons over a wide kinematic range, with polarizabilities characterizing the hadron active internal degrees of freedom. We present calculations and detailed analysis of electric and magnetic and the spin-dependent dynamical polarizabilities for the lowest in mass SU(3) octet of baryons. These extensive calculations are made possible by the recent implementation of semi-automatized calculations in chiral...
Topics: High Energy Physics - Phenomenology, Nuclear Theory
Source: http://arxiv.org/abs/1301.1383
Arxiv.org
texts

eye 51

favorite 0

comment 0

The aim of this paper is to obtain the fundamental tone for minimal submanifolds of the Euclidean or hyperbolic space under certain restrictions on the extrinsic curvature. We show some sufficient conditions on the norm of the second fundamental form that allow us to obtain the same upper and lower bound for the fundamental tone of minimal submanifolds in a Cartan-Hadamard ambient manifold. As an intrinsic result, we obtain a sufficient condition on the volume growth of a Cartan-Hadamard...
Topics: Mathematics, Differential Geometry
Source: http://arxiv.org/abs/1301.1148
Arxiv.org
by The BESIII Collaboration; M. Ablikim; M. N. Achasov; O. Albayrak; D. J. Ambrose; F. F. An; Q. An; J. Z. Bai; Y. Ban; J. Becker; J. V. Bennett; M. Bertani; J. M. Bian; E. Boger; O. Bondarenko; I. Boyko; R. A. Briere; V. Bytev; X. Cai; O. Cakir; A. Calcaterra; G. F. Cao; S. A. Cetin; J. F. Chang; G. Chelkov; G. Chen; H. S. Chen; J. C. Chen; M. L. Chen; S. J. Chen; X. Chen; Y. B. Chen; H. P. Cheng; Y. P. Chu; D. Cronin-Hennessy; H. L. Dai; J. P. Dai; D. Dedovich; Z. Y. Deng; A. Denig; I....
texts

eye 61

favorite 0

comment 0

We search for the M1 radiative transition \psi(3686) \to \gamma\eta_{c}(2S) by reconstructing the exclusive \eta_{c}(2S) \to K_{S}^{0}K^{\pm}\pi^{\mp}\pi^{+}\pi^{-} decay using 1.06 \times 10^8 \psi(3686) events collected with the BESIII detector. The signal is observed with a statistical significance of greater than 4 standard deviations. The measured mass of the \eta_{c}(2S) is 3646.9 \pm 1.6(stat) \pm 3.6(syst) MeV/c^2, and the width is 9.9 \pm 4.8(stat) \pm 2.9(syst) MeV/c^2. The product...
Topic: High Energy Physics - Experiment
Source: http://arxiv.org/abs/1301.1476
It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep--elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle...
Topics: High Energy Physics - Experiment, High Energy Physics - Phenomenology
Source: http://arxiv.org/abs/1301.0398
Arxiv.org
texts

eye 60

favorite 0

comment 0

In this paper, we investigate the vanishing viscosity limit problem for the 3-dimensional (3D) incompressible Navier-Stokes equations in a general bounded smooth domain of $R^3$ with the generalized Navier-slip boundary conditions (\ref{VSg}). Some uniform estimates on rates of convergence in $C([0,T],L^2(\Omega))$ and $C([0,T],H^1(\Omega))$ of the solutions to the corresponding solutions of the idea Euler equations with the standard slip boundary condition are obtained.
Topics: Mathematics, Analysis of PDEs
Source: http://arxiv.org/abs/1301.0693
Arxiv.org
by Hai-Jhun Wanng
texts

eye 42

favorite 0

comment 0

In the light of their relationships with renormalization, in this paper we associate the scaling transformation with nonlocal interactions. On one hand, the association leads us to interpret the nonlocality with locally symmetric method. On the other hand, we find that the nonlocal interaction between hadrons could be test ground for scaling transformation if ascribing the running effects in renormalization to scaling transformation. First we derive directly from group theory the...
Topics: High Energy Physics - Phenomenology, High Energy Physics - Theory
Source: http://arxiv.org/abs/1301.0258
Arxiv.org
by Rahim Moradi; Javad T. Firouzjaee; Reza Mansouri
texts

eye 44

favorite 0

comment 0

We have constructed a spherically symmetric structure model in a cosmological background filled with perfect fluid with non-vanishing pressure and studied its quasi-local characteristics. This is done by using the Lema\^{i}tre solution of the Einstein equations and suggesting an algorithm to integrate it numerically. The result shows intriguing effects of the pressure inside the structure. The evolution of the central black hole within the FRW universe, its decoupling from the expanding parts...
Topics: Astrophysics of Galaxies, General Relativity and Quantum Cosmology, Astrophysics
Source: http://arxiv.org/abs/1301.1480
Arxiv.org
texts

eye 67

favorite 0

comment 0

In this paper, we study a class of second order backward stochastic differential equations (2BSDEs) with quadratic growth in coefficients. We first establish solvability for such 2BSDEs and then give their applications to robust utility maximization problems.
Topics: Mathematics, Probability
Source: http://arxiv.org/abs/1301.0457
Arxiv.org
texts

eye 95

favorite 0

comment 0

Prion diseases caused by the conversion from a soluble normal cellular prion protein into insoluble abnormally folded infectious prions, are invariably fatal and highly infectious degenerative diseases that affect a wide variety of mammalian species. The palindrome and the Glycine-rich conserved segment in the hydrophobic region 109-136 control the conversion from normal prion protein to form into diseased prions. This paper gives detailed reviews on the 109-136 region and presents the studies...
Topics: Quantitative Biology, Physics, Biomolecules, Biological Physics
Source: http://arxiv.org/abs/1301.0117
Arxiv.org
by Said Aissaoui; Abdenacer Makhlouf
texts

eye 61

favorite 0

comment 0

The purpose of this paper is to investigate finite-dimensional superbialgebras and Hopf superalgebras. We study connected superbialgebras and provide a classification of non-trivial superbialgebras and Hopf superalgebras in dimension $n$ with $n\leq 4$.
Topics: Mathematical Physics, Mathematics, Rings and Algebras, Quantum Algebra
Source: http://arxiv.org/abs/1301.0838
Arxiv.org
by Eric J. Lentz; Stephen W. Bruenn; J. Austin Harris; Merek Austin Chertkow; W. Raphael Hix; Anthony Mezzacappa; O. E. Bronson Messer; John M. Bondin; Pedro Marronetti; Christopher M. Mauney; Konstantin N. Yakunin
texts

eye 49

favorite 0

comment 0

Ascertaining the core-collapse supernova mechanism is a complex, and yet unsolved, problem dependent on the interaction of general relativity, hydrodynamics, neutrino transport, neutrino-matter interactions, and nuclear equations of state and reaction kinetics. Ab initio modeling of core-collapse supernovae and their nucleosynthetic outcomes requires care in the coupling and approximations of the physical components. We have built our multi-physics CHIMERA code for supernova modeling in 1-, 2-,...
Topics: Astrophysics, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1301.1326
Arxiv.org
by Andrey V. Tsiganov
texts

eye 52

favorite 0

comment 0

We discuss trivial deformations of the canonical Poisson brackets associated with the Toda lattices, relativistic Toda lattices, Henon-Heiles, rational Calogero-Moser and Ruijsenaars-Schneider systems and apply one of these deformations to construct a new trivial family of noncommutative integrable systems.
Topics: Nonlinear Sciences, Mathematical Physics, Mathematics, Dynamical Systems, Exactly Solvable and...
Source: http://arxiv.org/abs/1301.1432
Arxiv.org
texts

eye 109

favorite 0

comment 0

This is the second paper of our series. In this paper, we present $UBVRI$ photometry for 234 star clusters in the field of M33. For most of these star clusters, there is photometry in only two bands in previous studies. The photometry of these star clusters is performed using archival images from the Local Group Galaxies Survey, which covers 0.8 deg$^2$ along the major axis of M33. Detailed comparisons show that, in general, our photometry is consistent with previous measurements, especially,...
Topics: Astrophysics of Galaxies, Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1301.1086
Arxiv.org
texts

eye 39

favorite 0

comment 0

In this paper, we have calculated the thermodynamic properties of spin polarized strange quark matter at finite temperature in the presence of a strong magnetic field using MIT bag model. We have also computed the equation of state of spin polarized strange quark matter in the presence of strong magnetic field and finally, using this equation of states we have investigated the structure of spin polarized strange quark star at different temperatures and magnetic fields.
Topics: Astrophysics, High Energy Physics - Phenomenology, Solar and Stellar Astrophysics
Source: http://arxiv.org/abs/1301.0899
Arxiv.org
by Amarendra Badugu; Conradin Kraemer; Philipp Germann; Denis Menshykau; Dagmar Iber
texts

eye 66

favorite 0

comment 0

Turing models have been proposed to explain the emergence of digits during limb development. However, so far the molecular components that would give rise to Turing patterns are elusive. We have recently shown that a particular type of receptor-ligand interaction can give rise to Schnakenberg-type Turing patterns, which reproduce patterning during lung and kidney branching morphogenesis. Recent knock-out experiments have identified Smad4 as a key protein in digit patterning. We show here that...
Topics: Tissues and Organs, Quantitative Biology, Molecular Networks
Source: http://arxiv.org/abs/1301.0736
Arxiv.org
texts

eye 52

favorite 0

comment 0

This paper is dedicated to provide the global solutions of algebro-geometric type for all the equations of a new commuting hierarchy containing the Hunter-Saxton (HS) equation. Our main tools include the zero curvature method to derive the HS hierarchy, the generalized Jacobian variety, the generalized Riemann theta function, the Weyl $m$-fucntions $m_\pm(x,t,z)$, and the pole motion obtained by solving an inverse problem for the Sturm-Liouville equation...
Topics: Nonlinear Sciences, Exactly Solvable and Integrable Systems
Source: http://arxiv.org/abs/1301.0690
Arxiv.org
by Changzheng Qu; Junfeng Song; Ruoxia Yao
texts

eye 34

favorite 0

comment 0

In this paper, multi-component generalizations to the Camassa-Holm equation, the modified Camassa-Holm equation with cubic nonlinearity are introduced. Geometric formulations to the dual version of the Schr\"odinger equation, the complex Camassa-Holm equation and the multi-component modified Camassa-Holm equation are provided. It is shown that these equations arise from non-streching invariant curve flows respectively in the three-dimensional Euclidean geometry, the two-dimensional...
Topics: Nonlinear Sciences, Mathematical Physics, Mathematics, Differential Geometry, Exactly Solvable and...
Source: http://arxiv.org/abs/1301.0180
Arxiv.org
by Jan Hrnčíř; Michael Rovatsos
texts

eye 61

favorite 0

comment 0

Travel sharing, i.e., the problem of finding parts of routes which can be shared by several travellers with different points of departure and destinations, is a complex multiagent problem that requires taking into account individual agents' preferences to come up with mutually acceptable joint plans. In this paper, we apply state-of-the-art planning techniques to real-world public transportation data to evaluate the feasibility of multiagent planning techniques in this domain. The potential...
Topics: Artificial Intelligence, Computing Research Repository
Source: http://arxiv.org/abs/1301.0216
Arxiv.org
texts

eye 77

favorite 0

comment 0

Given a set of mixtures, blind source separation attempts to retrieve the source signals without or with very little information of the the mixing process. We present a geometric approach for blind separation of nonnegative linear mixtures termed {\em facet component analysis} (FCA). The approach is based on facet identification of the underlying cone structure of the data. Earlier works focus on recovering the cone by locating its vertices (vertex component analysis or VCA) based on a mutual...
Topics: Machine Learning, Mathematics, Statistics, Numerical Analysis
Source: http://arxiv.org/abs/1301.0339
Arxiv.org
by A. Akyuz; S. Kayaci; H. Avdan; M. E. Ozel; E. Sonbas; S. Balman
texts

eye 51

favorite 0

comment 0

We present results from a study of the non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources has been detected within the D25 regions of the target galaxies. The large collecting area of XMM-Newton makes the statistics sufficient to obtain spectral fitting for 16 (about 20%) of these sources. Compiling the extensive...
Topics: Astrophysics, High Energy Astrophysical Phenomena
Source: http://arxiv.org/abs/1301.1040
Arxiv.org
by M. Aghapournahr; Kh. Ahmadi-amoli; M. Y. Sadeghi
texts

eye 55

favorite 0

comment 0

Some affirmative answers are given to Huneke's problems. The calculation of local cohomology modules with respect to an arbitrary pair of ideals $I,J$ can be reduced to calculation of local cohomology modules with respect to a pair of ideala whose first ideal is generated by any $k$-regular sequence in $I$.
Topics: Mathematics, Commutative Algebra
Source: http://arxiv.org/abs/1301.1015
Arxiv.org
by David Wingate; Theophane Weber
texts

eye 86

favorite 0

comment 0

We present a new algorithm for approximate inference in probabilistic programs, based on a stochastic gradient for variational programs. This method is efficient without restrictions on the probabilistic program; it is particularly practical for distributions which are not analytically tractable, including highly structured distributions that arise in probabilistic programs. We show how to automatically derive mean-field probabilistic programs and optimize them, and demonstrate that our...
Topics: Machine Learning, Learning, Computing Research Repository, Statistics, Artificial Intelligence
Source: http://arxiv.org/abs/1301.1299
Arxiv.org
by Junchao Chen; Xiangpeng Xin; Yong Chen
texts

eye 66

favorite 0

comment 0

The nonlocal symmetry is derived from the known Darboux transformation (DT) of the Hirota-Satsuma coupled KdV (HS-cKdV) system, and infinitely many nonlocal symmetries are obtained by introducing some internal parameters. By extending the HS-cKdV system to an auxiliary system with five dependent variables, the prolongation is found to localize the nonlocal symmetry related to the DT. Base on the enlarged system, the finite symmetry transformations and similarity reductions about the local...
Topics: Nonlinear Sciences, Exactly Solvable and Integrable Systems
Source: http://arxiv.org/abs/1301.0438
Arxiv.org
texts

eye 88

favorite 0

comment 0

We give a categorical semantics for a call-by-value linear lambda calculus. Such a lambda calculus was used by Selinger and Valiron as the backbone of a functional programming language for quantum computation. One feature of this lambda calculus is its linear type system, which includes a duplicability operator "!" as in linear logic. Another main feature is its call-by-value reduction strategy, together with a side-effect to model probabilistic measurements. The "!"...
Source: http://arxiv.org/abs/0801.0813v1
Arxiv.org
texts

eye 42

favorite 0

comment 0

We investigate the dephasing effect of the Kondo singlet in an Aharonov-Bohm interferometer with a quantum dot coupling to left and right electrodes. By employing the cluster expansions, the equations of motion of Green functions are transformed into the corresponding equation of motion of connected Green functions, which contains the correlation of two conduction electrons beyond the Lacroix approximation. With the method we show that the Kondo resonance is suppressed by phase-sensitive...
Source: http://arxiv.org/abs/0801.0539v2
Arxiv.org
texts

eye 52

favorite 0

comment 0

XML database query languages such as XQuery employ regular expression types with structural subtyping. Subtyping systems typically have two presentations, which should be equivalent: a declarative version in which the subsumption rule may be used anywhere, and an algorithmic version in which the use of subsumption is limited in order to make typechecking syntax-directed and decidable. However, the XQuery standard type system circumvents this issue by using imprecise typing rules for iteration...
Source: http://arxiv.org/abs/0801.0714v1
Arxiv.org
by Jeff M. Phillips
texts

eye 43

favorite 0

comment 0

Consider a point set D with a measure function w : D -> R. Let A be the set of subsets of D induced by containment in a shape from some geometric family (e.g. axis-aligned rectangles, half planes, balls, k-oriented polygons). We say a range space (D, A) has an eps-approximation P if max {R \in A} | w(R \cap P)/w(P) - w(R \cap D)/w(D) |
Source: http://arxiv.org/abs/0801.2793v2
Arxiv.org
by Nan Li; Marina Seikel; Dominik J. Schwarz
texts

eye 38

favorite 0

comment 0

The present standard model of cosmology states that the known particles carry only a tiny fraction of total mass and energy of the Universe. Rather, unknown dark matter and dark energy are the dominant contributions to the cosmic energy budget. We review the logic that leads to the postulated dark energy and present an alternative point of view, in which the puzzle may be solved by properly taking into account the influence of cosmic structures on global observables. We illustrate the effect of...
Source: http://arxiv.org/abs/0801.3420v1
Arxiv.org
by Vicente Munoz; Francisco Presas
texts

eye 44

favorite 0

comment 0

Is is known that the loop space associated to a Riemannian manifold admits a quasi-symplectic structure. This article shows that this structure is not likely to recover the underlying Riemannian metric by proving a result that is a strong indication of the "almost" independence of the quasi-symplectic structure with respect to the metric. Finally conditions to have contact structures on these spaces are studied.
Source: http://arxiv.org/abs/0801.3545v2
Arxiv.org
by Robert B. Burckel; Donald E. Marshall; David Minda; Pietro Poggi-Corradini; Thomas J. Ransford
texts

eye 73

favorite 0

comment 0

The now canonical proof of Schwarz's Lemma appeared in a 1907 paper of Carath\'eodory, who attributed it to Erhard Schmidt. Since then, Schwarz's Lemma has acquired considerable fame, with multiple extensions and generalizations. Much less known is that, in the same year 1907, Landau and Toeplitz obtained a similar result where the diameter of the image set takes over the role of the maximum modulus of the function. We give a new proof of this result and extend it to include bounds on the...
Source: http://arxiv.org/abs/0801.3629v1
Arxiv.org
by Michael H. Köpf; Gernot Münster
texts

eye 36

favorite 0

comment 0

In the rough phase, the width of interfaces separating different phases of statistical systems increases logarithmically with the system size. This phenomenon is commonly described in terms of the capillary wave model, which deals with fluctuating, infinitely thin membranes, requiring ad hoc cut-offs in momentum space. We investigate the interface roughening from first principles in the framework of the Landau-Ginzburg model, that is renormalized field theory, in the one-loop approximation. The...
Source: http://arxiv.org/abs/0801.3598v1
Arxiv.org
by Guanghan Li; Isabel M. C. Salavessa
texts

eye 108

favorite 0

comment 0

We generalize a Bernstein-type result due to Albujer and Al\'ias, for maximal surfaces in a curved Lorentzian product 3-manifold of the form $\Sigma_1\times \mathbb{R}$, to higher dimension and codimension. We consider $M$ a complete spacelike graphic submanifold with parallel mean curvature, defined by a map $f: \Sigma_1\to \Sigma_2$ between two Riemannian manifolds $(\Sigma_1^m, g_1)$ and $(\Sigma^n_2, g_2)$ of sectional curvatures $K_1$ and $K_2$, respectively. We take on $\Sigma_1\times...
Source: http://arxiv.org/abs/0801.3850v5
Arxiv.org
by Changxing Miao; Guixiang Xu; Lifeng Zhao
texts

eye 128

favorite 0

comment 0

We establish global well-posedness and scattering for solutions to the mass-critical nonlinear Hartree equation $iu_t+\Delta u=\pm(|x|^{-2}*|u|^2)u$ for large spherically symmetric $L^2_x(\Bbb{R}^d)$ initial data; in the focusing case we require, of course, that the mass is strictly less than that of the ground state.
Source: http://arxiv.org/abs/0801.3925v2
Arxiv.org
texts

eye 53

favorite 0

comment 0

In this paper, we study the regularities of solutions of nonlinear stochastic partial differential equations in the framework of Hilbert scales. Then we apply our general result to several typical nonlinear SPDEs such as stochastic Burgers and Ginzburg-Landau's equations on the real line, stochastic 2D Navier-Stokes equations in the whole space and a stochastic tamed 3D Navier-Stokes equation in the whole space, and obtain the existence of their respectively smooth solutions.
Source: http://arxiv.org/abs/0801.3883v1
Arxiv.org
by Andrew Corrigan; John Wallin; Thomas Wanner
texts

eye 45

favorite 0

comment 0

To improve convergence results obtained using a framework for unsymmetric meshless methods due to Schaback (Preprint G\"ottingen 2006), we extend, in two directions, the Sobolev bound due to Arcang\'eli et al. (Numer Math 107, 181-211, 2007), which itself extends two others due to Wendland and Rieger (Numer Math 101, 643-662, 2005) and Madych (J. Approx Theory 142, 116-128, 2006). The first is to incorporate discrete samples of arbitrary order derivatives into the bound, which are used to...
Source: http://arxiv.org/abs/0801.4097v3
Arxiv.org
by Wolfgang Altmannshofer; Diego Guadagnoli; Stuart Raby; David M. Straub
texts

eye 41

favorite 0

comment 0

We address the viability of exact Yukawa unification in the context of general SUSY GUTs with universal soft-breaking sfermion and gaugino mass terms at the GUT scale. We find that this possibility is challenged, unless the squark spectrum is pushed well above the limits allowed by naturalness. This conclusion is assessed through a global fit using electroweak observables and quark flavour-changing neutral current (FCNC) processes. The problem is mostly the impossibility of accommodating...
Source: http://arxiv.org/abs/0801.4363v3
Arxiv.org
by L. Ya. Glozman; A. V. Nefediev
texts

eye 37

favorite 0

comment 0

We compare axial charges of excited nucleons, as predicted by the chiral symmetry restoration picture, with the traditional, moderately successful for the ground-state baryons SU(6) symmetry. The axial charges of excited nucleons can (and will) be measured in lattice QCD simulations, and comparison of the lattice results with the two different symmetry schemes will give an insight on the origins of the excited hadron masses as well as on interrelations of chiral symmetry and confinement.
Source: http://arxiv.org/abs/0801.4343v2
Arxiv.org
by Michal P. Heller; Romuald A. Janik; Tomasz Lukowski
texts

eye 44

favorite 0

comment 0

In this paper we give a new derivation of the generalized Luscher F-term formula from a summation over quadratic fluctuations around a given soliton. The result is very general providing that S-matrix is diagonal and is valid for arbitrary dispersion relation. We then apply this formalism to compute the leading finite size corrections to the giant magnon dispersion relation coming from quantum fluctuations.
Source: http://arxiv.org/abs/0801.4463v3
Arxiv.org
by David B. Chandler; Peter Sin; Qing Xiang
texts

eye 40

favorite 0

comment 0

We study the permutation action of a finite symplectic group of characteristic 2 on the set of subspaces of its standard module which are either totally isotropic or else complementary to totally isotropic subspaces with respect to the alternating form. A general formula is obtained for the 2-rank of the incidence matrix for the inclusion of one-dimensional subspaces in the distinguished subspaces of a fixed dimension.
Source: http://arxiv.org/abs/0801.4392v1
Arxiv.org
by R. T. Braun; W. Tornow; C. R. Howell; D. E. Gonzalez Trotter; C. D. Roper; F. Salinas; H. R. Setze; R. L. Walter; G. J. Weisel
texts

eye 45

favorite 0

comment 0

We present the most accurate and complete data set for the analyzing power Ay(theta) in neutron-proton scattering. The experimental data were corrected for the effects of multiple scattering, both in the center detector and in the neutron detectors. The final data at En = 12.0 MeV deviate considerably from the predictions of nucleon-nucleon phase-shift analyses and potential models. The impact of the new data on the value of the charged pion-nucleon coupling constant is discussed in a model...
Source: http://arxiv.org/abs/0801.4600v1
Arxiv.org
texts

eye 46

favorite 0

comment 0

We investigate the predictability of extreme events in time series. The focus of this work is to understand under which circumstances large events are better predictable than smaller events. Therefore we use a simple prediction algorithm based on precursory structures which are identified using the maximum likelihood principle. Using the receiver operator characteristic curve as a measure for the quality of predictions we find that the dependence on the event magnitude is closely linked to the...
Source: http://arxiv.org/abs/0801.4525v1
Arxiv.org
by Valeria Kagramanova; Jutta Kunz; Claus Lämmerzahl
texts

eye 56

favorite 0

comment 0

The Pleba\'{n}ski--Demia\'{n}ski solution is a very general axially symmetric analytical solution of the Einstein field equations generalizing the Kerr solution. This solution depends on seven parameters which under certain circumstances are related to mass, rotation, cosmological constant, NUT parameter, electric and magnetic charges, and acceleration. In this paper we present a general description of matter wave interferometry in the general Pleba\'{n}ski--Demia\'{n}ski black hole...
Source: http://arxiv.org/abs/0801.4514v3
Arxiv.org
by Xavier Bressaud; Fabien Durand; Alejandro Maass
texts

eye 54

favorite 0

comment 0

We give necessary and sufficient conditions to have measurable and continuous eigenfunctions for linearly recurrent Cantor dynamical systems. We also construct explicitly an example of linearly recurrent system with nontrivial Kronecker factor and a trivial maximal equicontinuous factor.
Source: http://arxiv.org/abs/0801.4619v1
Arxiv.org
by B. Georgeot; O. Giraud
texts

eye 50

favorite 0

comment 0

We show that semiclassical formulas such as the Gutzwiller trace formula can be implemented on a quantum computer more efficiently than on a classical device. We give explicit quantum algorithms which yield quantum observables from classical trajectories, and which alternatively test the semiclassical approximation by computing classical actions from quantum evolution. The gain over classical computation is in general quadratic, and can be larger in some specific cases.
Source: http://arxiv.org/abs/0801.4660v1
Arxiv.org
by S. Ortolani; C. Bonatto; E. Bica; Y. Momany; B. Barbuy
texts

eye 25

favorite 0

comment 0

We derive fundamental parameters of the embedded cluster DBSB48 in the southern nebula Hoffleit18 and the very young open cluster Trumpler14, by means of deep JHKs infrared photometry. We build colour-magnitude and colour-colour diagrams to derive reddening and age, based on main sequence and pre-main sequence distributions. Radial stellar density profiles are used to study cluster structure and guide photometric diagram extractions. Field-star decontamination is applied to uncover the...
Source: http://arxiv.org/abs/0801.4661v1
Arxiv.org
by M. Guttormsen; R. Chankova; U. Agvaanluvsan; E. Algin; L. A. Bernstein; F. Ingebretsen; T. Lonnroth; S. Messelt; G. E. Mitchell; J. Rekstad; A. Schiller; S. Siem; A. C. Larsen; A. Voinov; S. Odegaard
texts

eye 62

favorite 0

comment 0

The radiative strength functions of 96Mo have been reanalyzed. The enhanced gamma strength for E_gamma < 3 - 4 MeV is confirmed.
Source: http://arxiv.org/abs/0801.4667v1
Arxiv.org
by Meng-Chwan Tan; Junya Yagi
texts

eye 39

favorite 0

comment 0

We explore the nonperturbative aspects of the chiral algebras of N = (0,2) sigma models, which perturbatively are intimately related to the theory of chiral differential operators (CDOs). The grading by charge and scaling dimension is anomalous if the first Chern class of the target space is nonzero. This has some nontrivial consequences for the chiral algebra. As an example, we study the case where the target space is CP^1, and show that worldsheet instantons trivialize the chiral algebra...
Source: http://arxiv.org/abs/0801.4782v3
Arxiv.org
by Bjorn Emonts; Raffaella Morganti; Tom Oosterloo; Jacqueline van Gorkom
texts

eye 34

favorite 0

comment 0

We present results of a study of large-scale neutral hydrogen (HI) gas in nearby radio galaxies. We find that the early-type host galaxies of different types of radio sources (compact, FR-I and FR-II) appear to contain fundamentally different large-scale HI properties: enormous regular rotating disks and rings are present around the host galaxies of a significant fraction of low power compact radio sources, while no large-scale HI is detected in low power, edge-darkened FR-I radio galaxies....
Source: http://arxiv.org/abs/0801.4769v1
Arxiv.org
texts

eye 57

favorite 0

comment 0

The relation between the quasinormal modes (QNMs) and the second order thermodynamic phase transition (SOTPT) for the Reissner-Nordstr\"om (RN) black hole is studied. It is shown that the quasinormal frequencies of the RN black hole start to get a spiral-like shape in the complex $\omega$ plane and both the real and imaginary parts become the oscillatory functions of the charge if the real part of the quasinormal frequencies arrives at its maximum at the second order phase transition point...
Source: http://arxiv.org/abs/0802.0043v1
Arxiv.org
by J. Barilla; M. Lokajíček; P. Simr
texts

eye 49

favorite 0

comment 0

The understanding of inactivation radiobiological mechanism in individual cells is important when from one side the application of ionizing radiation to tumour therapy and from the other side the protection against radiation are to be effectively improved. Important part of this mechanism is double-strand break (DSB) formation; these DSB may be formed directly by impacting ionizing particles or indirectly by different secondary radicals. The latter kind of formation is much more frequent when...
Source: http://arxiv.org/abs/0801.4880v1
Arxiv.org
by Todd Fisher
texts

eye 46

favorite 0

comment 0

We show there is a residual set of non-Anosov $C^{\infty}$ Axiom A diffeomorphisms with the no cycles property whose elements have trivial centralizer. If $M$ is a surface and $2\leq r\leq \infty$, then we will show there exists an open and dense set of of $C^r$ Axiom A diffeomorphisms with the no cycles property whose elements have trivial centralizer. Additionally, we examine commuting diffeomorphisms preserving a compact invariant set $\Lambda$ where $\Lambda$ is a hyperbolic chain recurrent...
Source: http://arxiv.org/abs/0801.4948v1
Arxiv.org
texts

eye 83

favorite 0

comment 0

We introduce a complex relativistic phase space as the space $\mathbb{C}^4$ equipped with the Minkowski metric and with a geometric tri-product on it. The geometric tri-product is similar to the triple product of the bounded symmetric domain of type IV in Cartan's classification, called the spin domain. We define a spin 1 representations of the Lie algebra of the Poincar\'{e} group by natural operators of this tri-product on the complex relativistic phase space. This representation is connected...
Source: http://arxiv.org/abs/0802.0070v1
Arxiv.org
by D. Ezri; B. Z. Bobrovsky; Z. Schuss
texts

eye 58

favorite 0

comment 0

We employ the variational formulation and the Euler-Lagrange equations to study the steady-state error in linear non-causal estimators (smoothers). We give a complete description of the steady-state error for inputs that are polynomial in time. We show that the steady-state error regime in a smoother is similar to that in a filter of double the type. This means that the steady-state error in the optimal smoother is significantly smaller than that in the Kalman filter. The results reveal a...
Source: http://arxiv.org/abs/0802.0130v1
Arxiv.org
by Mikhail Kapranov
texts

eye 60

favorite 0

comment 0

We identify the category of real mixed Hodge structures with the category of vector bundles with connections (not necessarily flat) on C, equivariant with respect to C^*. Here C is the complex plane considered as a 2-dimensional real manifold, and C^* is the multiplicative group of complex numbers considered as a real group.
Source: http://arxiv.org/abs/0802.0215v2
Arxiv.org
by Parsa Bonderson; Michael Freedman; Chetan Nayak
texts

eye 83

favorite 0

comment 0

We remove the need to physically transport computational anyons around each other from the implementation of computational gates in topological quantum computing. By using an anyonic analog of quantum state teleportation, we show how the braiding transformations used to generate computational gates may be produced through a series of topological charge measurements.
Source: http://arxiv.org/abs/0802.0279v2
Arxiv.org
by S. Aigner; L. Della Pietra; Y. Japha; O. Entin-Wohlman; T. David; R. Salem; R. Folman; J. Schmiedmayer
texts

eye 50

favorite 0

comment 0

Ultracold atom magnetic field microscopy enables the probing of current flow patterns in planar structures with unprecedented sensitivity. In polycrystalline metal (gold) films we observe long-range correlations forming organized patterns oriented at +/- 45 deg relative to the mean current flow, even at room temperature and at length scales orders of magnitude larger than the diffusion length or the grain size. The preference to form patterns at these angles is a direct consequence of universal...
Source: http://arxiv.org/abs/0802.0386v1
Arxiv.org
texts

eye 44

favorite 0

comment 0

Quantum electrodynamics in 2+1 dimensions is an effective gauge theory for the so called algebraic quantum liquids. A new type of such a liquid, the algebraic charge liquid, has been proposed recently in the context of deconfined quantum critical points [R. K. Kaul {\it et al.}, Nature Physics {\bf 4}, 28 (2008)]. In this context, we show by using the renormalization group in $d=4-\epsilon$ spacetime dimensions, that a deconfined quantum critical point occurs in a SU(2) system provided the...
Source: http://arxiv.org/abs/0802.0500v3
Arxiv.org
by Veit Elser; Simon Gravel
texts

eye 45

favorite 0

comment 0

We use the automorphism group $Aut(H)$, of holes in the lattice $L_8=A_2\oplus A_2\oplus D_4$, as the starting point in the construction of sphere packings in 10 and 12 dimensions. A second lattice, $L_4=A_2\oplus A_2$, enters the construction because a subgroup of $Aut(L_4)$ is isomorphic to $Aut(H)$. The lattices $L_8$ and $L_4$, when glued together through this relationship, provide an alternative construction of the laminated lattice in twelve dimensions with kissing number 648. More...
Source: http://arxiv.org/abs/0802.0730v1
Arxiv.org
by Stephen S. Bullock; Dianne P. O'Leary
texts

eye 49

favorite 0

comment 0

This manuscript introduces various notions of k-locality of stabilizer codes inherited from the associated stabilizer groups. A choice of generators for the group leads to a Hamiltonian with the code in its groundspace, while a Hamiltonian holding the code in its groundspace might be called effective if its locality is less than that of a natural choice of generators (or any choice). This paper establishes some conditions under which effective Hamiltonians for stabilizer codes do not exist. Our...
Source: http://arxiv.org/abs/0802.0626v1
Arxiv.org
by Tim Hesterberg; Nam Hee Choi; Lukas Meier; Chris Fraley
texts

eye 112

favorite 0

comment 0

Least Angle Regression is a promising technique for variable selection applications, offering a nice alternative to stepwise regression. It provides an explanation for the similar behavior of LASSO ($\ell_1$-penalized regression) and forward stagewise regression, and provides a fast implementation of both. The idea has caught on rapidly, and sparked a great deal of research interest. In this paper, we give an overview of Least Angle Regression and the current state of related research.
Source: http://arxiv.org/abs/0802.0964v2
Arxiv.org
by Jungkai A. Chen; Christopher D. Hacon
texts

eye 50

favorite 0

comment 0

We show that if $X$ is a smooth complex projective variety with Kodaira dimension $0$ then the Kodaira dimension of a general fiber of its Albanese map is at most $h^0(\Omega ^1 _X)$.
Source: http://arxiv.org/abs/0802.1060v1
Arxiv.org
by Amandine Marrel; Bertrand Iooss; Beatrice Laurent; Olivier Roustant
texts

eye 60

favorite 0

comment 0

Global sensitivity analysis of complex numerical models can be performed by calculating variance-based importance measures of the input variables, such as the Sobol indices. However, these techniques, requiring a large number of model evaluations, are often unacceptable for time expensive computer codes. A well known and widely used decision consists in replacing the computer code by a metamodel, predicting the model responses with a negligible computation time and rending straightforward the...
Source: http://arxiv.org/abs/0802.1008v1
Arxiv.org
by Si Li; Le Anh Vinh
texts

eye 57

favorite 0

comment 0

We consider unitary graphs attached to Z_d^n using an analogue of the Euclidean distance. These graphs are shown to be integral when n is odd or the dimension d is even.
Source: http://arxiv.org/abs/0802.1231v2
Arxiv.org
by Barry F. Madore; Wendy L. Freedman; Gregory D. Bothun
texts

eye 46

favorite 0

comment 0

(Abridged) We investigate the number of physical companion galaxies for a sample of relatively isolated elliptical galaxies. NED has been used to reinvestigate the incidence of satellite galaxies for a sample of 34 elliptical galaxies, first investigated by Bothun & Sullivan in a visual search out to a projected search radius of 75 kpc. We have repeated their original investigation using data cataloged in NED. Nine of these elliptical galaxies appear to be members of galaxy clusters; the...
Source: http://arxiv.org/abs/0802.1354v1
Arxiv.org
by Ashkan Nikeghbali
texts

eye 76

favorite 0

comment 0

In this paper, using martingale techniques, we prove a generalization of Doob's maximal identity in the setting of continuous nonnegative local submartingales $(X_{t})$ of the form: $X_{t}=N_{t}+A_{t}$, where the measure $(dA_{t})$ is carried by the set $\left\{t: X_{t}=0\right\}$. In particular, we give a multiplicative decomposition for the Az\'ema supermartingale associated with some last passage times related to such processes and we prove that these non-stopping times contain very useful...
Source: http://arxiv.org/abs/0802.1317v1
Arxiv.org
by Juan Garcia-Bellido; Troels Haugboelle
texts

eye 91

favorite 0

comment 0

The possibility that we live in a special place in the universe, close to the centre of a large void, seems an appealing alternative to the prevailing interpretation of the acceleration of the universe in terms of a LCDM model with a dominant dark energy component. In this paper we confront the asymptotically flat Lemaitre-Tolman-Bondi (LTB) models with a series of observations, from Type Ia Supernovae to Cosmic Microwave Background and Baryon Acoustic Oscillations data. We propose two concrete...
Source: http://arxiv.org/abs/0802.1523v3
Arxiv.org
texts

eye 64

favorite 0

comment 0

We prove a generalisation of Elkies' theorem to nonunimodular definite forms (and lattices). Combined with inequalities of Froyshov and of Ozsvath and Szabo, this gives a simple test of whether a rational homology 3-sphere may bound a definite four-manifold. As an example we show that small positive surgeries on torus knots do not bound negative-definite four-manifolds.
Source: http://arxiv.org/abs/0802.1495v1
Arxiv.org
by T. R. Govindarajan; Kumar S. Gupta; E. Harikumar; S. Meljanac; D. Meljanac
texts

eye 47

favorite 0

comment 0

We consider the issue of statistics for identical particles or fields in kappa-deformed spaces, where the system admits a symmetry group G. We obtain the twisted flip operator compatible with the action of the symmetry group, which is relevant for describing particle statistics in presence of the noncommutativity. It is shown that for a special class of realizations, the twisted flip operator is independent of the ordering prescription.
Source: http://arxiv.org/abs/0802.1576v2
Arxiv.org
by R. Pandharipande; A. Zinger
texts

eye 49

favorite 0

comment 0

Gromov-Witten theory is used to define an enumerative geometry of curves in Calabi-Yau 5-folds. We find recursions for meeting numbers of genus 0 curves, and we determine the contributions of moving multiple covers of genus 0 curves to the genus 1 Gromov-Witten invariants. The resulting invariants, conjectured to be integral, are analogous to the previously defined BPS counts for Calabi-Yau 3 and 4-folds. We comment on the situation in higher dimensions where new issues arise. Two main examples...
Source: http://arxiv.org/abs/0802.1640v1
Arxiv.org
texts

eye 57

favorite 0

comment 0

We propose an asymptotic expansion formula for matrix integrals, including oscillatory terms (derivatives of theta-functions) to all orders. This formula is heuristically derived from the analogy between matrix integrals, and formal matrix models (combinatorics of discrete surfaces), after summing over filling fractions. The whole oscillatory series can also be resummed into a single theta function. We also remark that the coefficients of the theta derivatives, are the same as those which...
Source: http://arxiv.org/abs/0802.1788v1
Arxiv.org
by Roman Sverdlov
texts

eye 61

favorite 0

comment 0

The goal of this paper is to present the way to define fermionic fields and their Lagrangians in terms of three orthogonal vector fields of norm 1 together with two real valued scalar fields. This paper is based on a toy model where there are no Grassmann variables.
Source: http://arxiv.org/abs/0802.1914v2
Arxiv.org
by L. S. Geng; J. Martin Camalich; L. Alvarez-Ruso; M. J. Vicente Vacas
texts

eye 47

favorite 0

comment 0

We have performed a theoretical study of the axial Nucleon to Delta(1232) ($N\to\Delta$) transition form factors up to one-loop order in covariant baryon chiral perturbation theory within a formalism in which the unphysical spin-1/2 components of the $\Delta$ fields are decoupled.
Source: http://arxiv.org/abs/0802.1834v1
Arxiv.org
by Louis Leblond; Sarah Shandera
texts

eye 44

favorite 0

comment 0

We examine the conditions under which a perturbative expansion around an inflating background is valid. When inflation is driven by a single field with a general sound speed, we find a lower limit on the sound speed related to the amplitude of the inflationary power spectrum. Generalizing the sound speed constraints to include scale dependence can limit the number of e-folds obtained in the perturbative regime and restrict otherwise apparently viable models. We also show that for models with a...
Source: http://arxiv.org/abs/0802.2290v3
Arxiv.org
texts

eye 85

favorite 0

comment 0

This paper introduces QuanFou v1.1, QuanGlue v1.1, QuanOracle v1.1, QuanShi v1.1, four Java applications available for free. (Source code included in the distribution.) Each application compiles a different kind of input quantum evolution operator. The applications output a quantum circuit that equals the input evolution operator.
Source: http://arxiv.org/abs/0802.2367v1
Arxiv.org
by G. A. Romero; C. E. Cappa
texts

eye 47

favorite 0

comment 0

We present a study of the HII region Sh2-205 and its environs, based on data obtained from the CGPS, 12CO observations, and MSX data. We find that Sh2-205 can be separated in three independent optical structures: SH 149.25-0.0, SH 148.83-0.67, and LBN 148.11-0.45. The derived spectral indices show the thermal nature of SH 148.83-0.67 and LBN 148.11-0.45. The morphology of SH 148.83-0.67, both in the optical and radio data, along with the energetic requ irements indicate that this feature is an...
Source: http://arxiv.org/abs/0802.2243v2
Arxiv.org
by V. A. Acciari; M. Beilicke; G. Blaylock; S. M. Bradbury; J. H. Buckley; V. Bugaev; Y. Butt; K. L. Byrum; O. Celik; A. Cesarini; L. Ciupik; Y. C. K. Chow; P. Cogan; P. Colin; W. Cui; M. K. Daniel; C. Duke; T. Ergin; A. D. Falcone; S. J. Fegan; J. P. Finley; P. Fortin; L. F. Fortson; D. Gall; K. Gibbs; G. H. Gillanders; J. Grube R. Guenette; D. Hanna; E. Hays; J. Holder; D. Horan; S. B. Hughes; C. M. Hui; T. B. Humensky; P. Kaaret; D. B. Kieda; J. Kildea; A. Konopelko; H. Krawczynski; F....
texts

eye 37

favorite 0

comment 0

LS I +61 303 is one of only a few high-mass X-ray binaries currently detected at high significance in very high energy gamma-rays. The system was observed over several orbital cycles (between September 2006 and February 2007) with the VERITAS array of imaging air-Cherenkov telescopes. A signal of gamma-rays with energies above 300 GeV is found with a statistical significance of 8.4 standard deviations. The detected flux is measured to be strongly variable; the maximum flux is found during most...
Source: http://arxiv.org/abs/0802.2363v1
Arxiv.org
texts

eye 64

favorite 0

comment 0

We consider random conformally invariant paths in the complex plane (SLEs). Using the Coulomb gas method in conformal field theory, we rederive the mixed multifractal exponents associated with both the harmonic measure and winding (rotation or monodromy) near such critical curves, previously obtained by quantum gravity methods. The results also extend to the general cases of harmonic measure moments and winding of multiple paths in a star configuration.
Source: http://arxiv.org/abs/0802.2280v1
Arxiv.org
by K. Beuermann; E. El Kholy; K. Reinsch
texts

eye 39

favorite 0

comment 0

Polars (AM Herculis binaries) are a prominent class of bright soft X-ray sources, many of which were discovered with ROSAT. We present a homogenous analysis of all the pointed ROSAT PSPC observations of polars subdivided into two papers that discuss the prototype polar AM Her in detail and summarize the class properties of all other polars. We derive the high-state soft X-ray flux and short-term spectral variability of AM Her using a new detector response matrix and a confirmed flux calibration...
Source: http://arxiv.org/abs/0802.2656v1
Arxiv.org
by Wei Hong; Xiaopu Han; Tao Zhou; Binghong Wang
texts

eye 45

favorite 0

comment 0

Short-message (SM) is one of the most frequently used communication channels in the modern society. In this Brief Report, based on the SM communication records provided by some volunteers, we investigate the statistics of SM communication pattern, including the interevent time distributions between two consecutive short messages and two conversations, and the distribution of message number contained by a complete conversation. In the individual level, the current empirical data raises a strong...
Source: http://arxiv.org/abs/0802.2577v1
Arxiv.org
texts

eye 42

favorite 0

comment 0

It is shown that the `arrow of time' operator, M_F, recently suggested by Strauss et al., in arXiv:0802.2448v1 [quant-ph], is simply related to the sign of the canonical `time' observable, T (apparently first introduced by Holevo). In particular, the monotonic decrease of < M_F > corresponds to the fact that < sgn T > increases monotonically with time. This relationship also provides a physical interpretation of the property M_F < 1. Some further properties and possible...
Source: http://arxiv.org/abs/0802.2682v2
Arxiv.org
by Lex E. Renner
texts

eye 45

favorite 0

comment 0

Let $(W,S)$ be a finite Weyl group and let $w\in W$. It is widely appreciated that the descent set D(w)=\{s\in S | l(ws)
Source: http://arxiv.org/abs/0802.2709v3
Arxiv.org
by George Miley; Carlos De Breuck
texts

eye 49

favorite 0

comment 0

We review the properties and nature of luminous high-redshift radio galaxies (HzRGs, z > 2) and the environments in which they are located. HzRGs have several distinct constituents which interact with each other - relativistic plasma, gas in various forms, dust, stars and an active galactic nucleus (AGN). These building blocks provide unique diagnostics about conditions in the early Universe. We discuss the properties of each constituent. Evidence is presented that HzRGs are massive forming...
Source: http://arxiv.org/abs/0802.2770v1
Arxiv.org
by Crystal L. Martin; Marcin Sawicki; Alan Dressler; Pat McCarthy
texts

eye 56

favorite 0

comment 0

We present results from a blind, spectroscopic survey for redshift ~5.7 Lyman-alpha-emitting galaxies using the Inamori Magellan Areal Camera and Spectrograph. A total of ~200 square arcminutes were observed in the COSMOS and LCIRS fields using a narrowband filter, which transmits between atmospheric emission lines at 8190 A, and a mask with 100 longslits. This observing technique provides higher emission-line sensitivity than narrowband imaging and probes larger volumes than strong lensing. We...
Source: http://arxiv.org/abs/0802.2393v1
Arxiv.org
by J. J. Sławianowski; V. Kovalchuk; A. Sławianowska; B. Gołubowska; A. Martens; E. E. Rożko; Z. J. Zawistowski
texts

eye 41

favorite 0

comment 0

Discussed is a model of collective and internal degrees of freedom with kinematics based on affine group and its subgroups. The main novelty in comparison with the previous attempts of this kind is that it is not only kinematics but also dynamics that is affinely-invariant. The relationship with the dynamics of integrable one-dimensional lattices is discussed. It is shown that affinely-invariant geodetic models may encode the dynamics of something like elastic vibrations.
Source: http://arxiv.org/abs/0802.3027v1
Arxiv.org
by B. Julsgaard; J. Johansen; S. Stobbe; T. Stolberg-Rohr; T. Sünner; M. Kamp; A. Forchel; P. Lodahl
texts

eye 48

favorite 0

comment 0

We have performed time-resolved spectroscopy on InAs quantum dot ensembles in photonic crystal membranes. The influence of the photonic crystal is investigated by varying the lattice constant systematically. We observe a strong slow down of the quantum dots' spontaneous emission rates as the two-dimensional bandgap is tuned through their emission frequencies. The measured band edges are in full agreement with theoretical predictions. We characterize the multi-exponential decay curves by their...
Source: http://arxiv.org/abs/0802.2947v2
Arxiv.org
by L. Balková; E. Pelantová
texts

eye 41

favorite 0

comment 0

We consider two {seemingly} different definitions of infinite words which contain {the} utmost number of palindromes. We show that these two definitions coincide. {The keynote of the proof is a meticulous inspection of properties of complete return words and the application of some basic graph theory.} In fact, we provide another proof of the result announced in \cite{Zamboni}.
Source: http://arxiv.org/abs/0802.2995v2
Arxiv.org
by A. M. Marino; V. Boyer; P. D. Lett
texts

eye 49

favorite 0

comment 0

We have observed a violation of the Cauchy-Schwarz inequality in the macroscopic regime by more than 8 standard deviations. The violation has been obtained while filtering out only the low frequency noise of the quantum-correlated beams that results from the technical noise of the laser used to generate them. We use bright intensity-difference squeezed beams produced by four-wave mixing as the source of the correlated fields. We also demonstrate that squeezing does not necessarily imply a...
Source: http://arxiv.org/abs/0802.3183v1
Arxiv.org
by Ulrich Goertz; Chia-Fu Yu
texts

eye 54

favorite 0

comment 0

We investigate Siegel modular varieties in positive characteristic with Iwahori level structure. On these spaces, we have the Newton stratification, and the Kottwitz-Rapoport stratification; one would like to understand how these stratifications are related to each other. We give a simple description of all KR strata which are entirely contained in the supersingular locus as disjoint unions of Deligne-Lusztig varieties. We also give an explicit numerical description of the KR stratification in...
Source: http://arxiv.org/abs/0802.3260v2
Arxiv.org
by S. Mereghetti; P. Romano; L. Sidoli
texts

eye 55

favorite 0

comment 0

We present recent observations of the X-ray pulsar SAX J1324-6200 obtained in December 2007 with the Swift satellite yielding a significant improvement in the source localization with respect to previous data and a new measurement of the spin period P=172.84s. A single object consistent in colors with a highly reddened early type star is visible in the X-ray error box. The period is significantly longer than that obtained in 1997, indicating that SAX J1324-6200 has been spinning down at an...
Source: http://arxiv.org/abs/0802.3388v1
Arxiv.org
by Jing Long Hoelscher
texts

eye 74

favorite 0

comment 0

This paper studies infinite class field towers of number fields $K$ that are ramified over $\Q$ only at one finite prime. In particular, we show the existence of such towers for a general family of primes including $p=2$, 3 and 5.
Source: http://arxiv.org/abs/0802.3461v2
Arxiv.org
by JongHae Keum
texts

eye 63

favorite 0

comment 0

Recently, Prasad and Yeung classified all possible fundamental groups of fake projective planes. According to their result, many fake projective planes admit a nontrivial group of automorphisms, and in that case it is isomorphic to $\bbZ/3\bbZ$, $\bbZ/7\bbZ$, $7:3$, or $(\bbZ/3\bbZ)^2$, where $7:3$ is the unique non-abelian group of order 21. Let $G$ be a group of automorphisms of a fake projective plane $X$. In this paper we classify all possible structures of the quotient surface $X/G$ and...
Source: http://arxiv.org/abs/0802.3435v4