February 2007 arXiv papers — page 9

Clement Gombeaud, Jean-Yves Ollitrault

We present a new direct simulation Monte-Carlo method for solving the relativistic Boltzmann equation. We solve numerically the 2-dimensional Boltzmann equation using this new algorithm. We find that elliptic flow from this transport calculation smoothly converges towards the value from ideal hydrodynamics as the number of collisions per particle increases,

C. G. Doudoulakis

A numerical search for straight superconducting vortices in a U(1) model with a Ginzburg-Landau potential containing a cubic term, is presented. Such vortices exist in a small numerically determined region. The reasons of their existence in that narrow region of the parameter space, as well as of their instability in the rest of the parameter space, are expl

Rosa Maia Duran Delgado, Gosta Gustafson, Leif Lonnblad

We investigate some recent measurements of Fermi--Dirac correlations by the LEP collaborations indicating surprisingly small source radii for the production of baryons in $e^+e^-$-annihilation at the $Z^0$ peak. In the hadronization models there are besides the Fermi--Dirac correlation effect also a strong dynamical (anti-)correlation. We demonstrate that th

V. R. Khalilov, F. Kh. Chibirova

We study the effect of a constant uniform magnetic field on an electrically charged massive particle (an electron) bound by a potential well, which is described by means of a single attractive $λδ({\bf r})$ potential. A transcendental equation that determines the electron energy spectrum is derived and solved. The electron wave function in the ground (bound)

Z. G. Dong, S. Y. Lei, Q. Li, M. X. Xu

A [pi]-shaped metallic metamaterial (geometrically, a combination medium of C-shaped resonators and continuous wires) is proposed to numerically investigate its transmission band near the resonant frequency, where otherwise it should be a negative-permeability (or negative-permittivity) stop band if either the C-shaped or continuous-wire constituent is separ

Alexander C. R. Belton

Quantum random walks are constructed on operator spaces with the aid of matrix-space lifting, a type of ampliation intermediate between those provided by spatial and ultraweak tensor products. Using a form of Wiener-Ito decomposition, a Donsker-type theorem is proved, showing that these walks, after suitable scaling, converge in a strong sense to vacuum cocy

Koji Harada, Hirofumi Kubo, Atsushi Ninomiya

We extend our Wilsonian renormalization group (RG) analysis on the pionless nuclear effective theory (NEFT) in the two-nucleon sector in two ways; on the one hand, (1) we enlarge the space of operators up to including those of $\mathcal{O}(p^4)$ in the $S$ waves, and, on the other hand, (2) we consider the RG flows in higher partial waves ($P$ and $D$ waves)

Elemer E Rosinger

This is a two part paper which discusses various issues of cosmic contact related to what so far appears to be a self-imposed censorship implied by the customary acceptance of the Archimedean assumption on space-time.

D. Boyanovsky, H. J. de Vega, C. M. Ho, N. G. Sanchez

The CMB power spectra are studied for different families of single field new and chaotic inflation models in the effective field theory approach to inflation. We implement a systematic expansion in 1/N_e where N_e ~ 50 is the number of e-folds before the end of inflation. We study the dependence of the observables (n_s, r and dn_s/d\ln k) on the degree of th

B. Cvetkovic, M. Blagojevic

We study the structure of asymptotic symmetries in N=1+1 supersymmetric extension of three-dimensional gravity with torsion. Using a natural generalization of the bosonic anti-de Sitter asymptotic conditions, we show that the asymptotic Poisson bracket algebra of the canonical generators has the form of two independent super-Virasoro algebras with different

Shi-Jie Xiong, S. J. Xu

A full quantum mechanical theory for the spontaneous emission from excitons simultaneously coupled to electronic excitations and anharmonic phonons in solid is developed. Origin of detailed structures, such as zero-phonon line splitting, Fano lineshape near one phonon sideband, strong second-order phonon Stokes line, asymmetric phonon anti-Stokes lines, and

CDF Collaboration

We present a measurement of sigma(p-pbar -> W) x B(W->enu) at sqrt{s}=1.96 TeV, using electrons identified in the forward region (1.2 <|eta|<2.8) of the CDF II detector in 223 pb-1 of data. We measure sigma x B = 2796 +-13(stat)+95-90(syst)+-162(lum)pb. Combining this result with a previous CDF measurement obtained using electrons in the central region (|eta

Pankaj Sati

The paper tries to identify new emerging patterns in the context of technological progress. Just as industrialization is associated with rationalization, mechanization, and automation, the Internet age is associated with computer models, embedded knowledge, and collaboration. Comparison among patterns is highlighted and analysis is done from predictability-b

Zhi-Guo He, Ying Fan, Kuang-Ta Chao

In order to clarify the puzzling problems in double charm production, relativistic corrections at order $v^{2}$ to the processes $e^{+}e^{-}\to J/\psi+\eta_{c}$ and $e^{+}e^{-}\to J/\psi+c\bar{c}$ at B factories are studied in non-relativistic quantum chromodynamics. The short-distance parts of production cross sections are calculated perturbatively, while t

B. Mosconi, P. Ricci, E. Truhlik, P. Vogel

Model dependence of the reaction rates for the weak breakup of deuterons by low energy neutrinos is studied starting from the cross sections derived from potential models and also from pionless effective field theory. Choosing the spread of the reaction yields, caused basically by the different ways the two-body currents are treated, as a measure of the mode

G. Giavaras, J. H. Jefferson, M. Fearn, C. J. Lambert

We propose a method of generating fully entangled electron spin pairs using an open static quantum dot and a moving quantum dot, realized by the propagation of a surface acoustic wave (SAW) along a quasi-one-dimensional channel in a semiconductor heterostructure. In particular, we consider a static dot (SD) loaded with two interacting electrons in a singlet

Timo Hanke

The isomorphism problem means to decide if two given finite-dimensional simple algebras over the same centre are isomorphic and, if so, to construct an isomorphism between them. A solution to this problem has applications in computational aspects of representation theory, algebraic geometry and Brauer group theory. The paper presents an algorithm for cyclic

D. M. Cardamone, B. R. Barrett, C. A. Stafford

Superdeformed nuclei in the 190 mass region exhibit a striking universality in their decay-out profiles. We show that this universality can be explained in the two-level model of superdeformed decay as related to a strong separation of energy scales: a higher scale related to the nuclear interactions, and a lower scale caused by electromagnetic decay. Furthe

Alceste Z. Bonanos

This paper presents the first optical variability study of the Westerlund 1 super star cluster in search of massive eclipsing binary systems. A total of 129 new variable stars have been identified, including the discovery of 4 eclipsing binaries that are cluster members, 1 additional candidate, 8 field binaries, 19 field delta Scuti stars, 3 field W UMa ecli

Takeshi Higashi, Kiyoshi Higashijima, Etsuko Itou

We construct novel conformal sigma models in three dimensions. Nonlinear sigma models in three dimensions are nonrenormalizable in perturbation theory. We use Wilsonian renormalization group equation method to find the fixed points. Existence of fixed points is extremely important in this approach to show the renormalizability. Conformal sigma models are def

Parongama Sen

We consider navigation or search schemes on networks which are realistic in the sense that not all search chains can be completed. We show that the quantity $μ= ρ/s_d$, where $s_d$ is the average dynamic shortest distance and $ρ$ the success rate of completion of a search, is a consistent measure for the quality of a search strategy. Taking the example of re

C. W. James, R. M. Crocker, R. D. Ekers, T. H. Hankins

The first search for ultra-high energy (UHE) neutrinos using a radio telescope was conducted by Hankins, Ekers and O&#39;Sullivan (1996). This was a search for nanosecond duration radio Cherenkov pulses from electromagnetic cascades initiated by ultra-high energy (UHE) neutrino interactions in the lunar regolith, and was made using a broad-bandwidth receiver

Zeev Rudnick, Igor Wigman

We study the volume of nodal sets for eigenfunctions of the Laplacian on the standard torus in two or more dimensions. We consider a sequence of eigenvalues $4π^2\eigenvalue$ with growing multiplicity $\Ndim\to\infty$, and compute the expectation and variance of the volume of the nodal set with respect to a Gaussian probability measure on the eigenspaces. We

R. Ball, P. Holmes

In this expository and resources chapter we review selected aspects of the mathematics of dynamical systems, stability, and chaos, within a historical framework that draws together two threads of its early development: celestial mechanics and control theory, and focussing on qualitative theory. From this perspective we show how concepts of stability enable u

Vikram Chandrasekhar, Jeffrey G. Andrews

Two-tier femtocell networks-- comprising a conventional macrocellular network plus embedded femtocell hotspots-- offer an economically viable solution to achieving high cellular user capacity and improved coverage. With universal frequency reuse and DS-CDMA transmission however, the ensuing cross-tier cochannel interference (CCI) causes unacceptable outage p

Ignacio Garcia-Mata, Andre R. R. Carvalho, Florian Mintert, Andreas Buchleitner

We show that nonlinear resonances in a classically mixed phase space allow to define generic, strongly entangled multi-partite quantum states. The robustness of their multipartite entanglement increases with the particle number, i.e. in the semiclassical limit, for those classes of diffusive noise which assist the quantum-classical transition.

R. J. Collins, R. H. Hadfield, V. Fernandez, S. W. Nam

A superconducting single-photon detector based on a niobium nitride nanowire is demonstrated in an optical-fibre-based quantum key distribution test bed operating at a clock rate of 3.3 GHz and a transmission wavelength of 850 nm. The low jitter of the detector leads to significant reduction in the estimated quantum bit error rate and a resultant improvement

Christoph Marquardt, Ulrik L. Andersen, Gerd Leuchs, Yuishi Takeno

We witness experimentally the presence of macroscopic coherence in Gaussian quantum states using a recently proposed criterion (E.G. Cavalcanti and M. Reid, Phys. Rev. Lett. 97, 170405 (2006)). The macroscopic coherence stems from interference between macroscopically distinct states in phase space and we prove experimentally that even the vacuum state contai

Sei Suzuki, Hidetoshi Nishimori, Masuo Suzuki

We introduce transverse ferromagnetic interactions, in addition to a simple transverse field, to quantum annealing of the random-field Ising model to accelerate convergence toward the target ground state. The conventional approach using only the transverse-field term is known to be plagued by slow convergence when the true ground state has strong ferromagnet

Luis F. Barragan-Gil, Abel Camacho

In the present work the conditions appearing in the WKB approximation formalism of quantum mechanics are analyzed. It is shown that, in general, a careful definition of an approximation method requires the introduction of two length parameters, one of them always considered in the text books on quantum mechanics, whereas the second one is usually neglected.

Elizabeth S. Allman, John A. Rhodes

The general Markov plus invariable sites (GM+I) model of biological sequence evolution is a two-class model in which an unknown proportion of sites are not allowed to change, while the remainder undergo substitutions according to a Markov process on a tree. For statistical use it is important to know if the model is identifiable; can both the tree topology a

Danuta Makowiec, Aleksandra Dudkowska, Rafal Galaska, Andrzej Rynkiewicz

Power spectral density is an accepted measure of heart rate variability. Two estimators of multifractal properties: Wavelet Transform Modulus Maxima and Multifractal Detrended Fluctuation Analysis are used to investigate multifractal properties for the three strongly physiologically grounded components of power spectra: low frequency (LF), very low frequency

Said Mikki, Ahmed A. Kishk

A new particle swarm optimization (PSO) technique for electromagnetic applications is proposed. The method is based on quantum mechanics rather than the Newtonian rules assumed in all previous versions of PSO, which we refer to as classical PSO. A general procedure is suggested to derive many different versions of the quantum PSO algorithm (QPSO). The QPSO i

Alexey Neelov, S. Alireza Ghasemi, Stefan Goedecker

An algorithm for fast calculation of the Coulombic forces and energies of point particles with free boundary conditions is proposed. Its calculation time scales as N log N for N particles. This novel method has lower crossover point with the full O(N^2) direct summation than the Fast Multipole Method. The forces obtained by our algorithm are analytical deriv

Said M. Mikki, Ahmed A. Kishk

The recently introduced quantum particle swarm optimization (QPSO) algorithm is employed to find infinitesimal dipole models (IDM) for antennas with known near-fields (measured or computed). The IDM can predict accurately both the near-fields and the far- fields of the antenna. A theory is developed to explain the mechanism behind the IDM using the multipole

De-en Jiang, Bobby G. Sumpter, Sheng Dai

The zigzag edge of a graphene nanoribbon possesses a unique electronic state that is near the Fermi level and localized at the edge carbon atoms. We investigate the chemical reactivity of these zigzag edge sites by examining their reaction energetics with common radicals from first principles. A &#34;partial radical&#34; concept for the edge carbon atoms is

I. Biro, B. Gyure, I. M. Janosi, K. G. Szabo

The free motion of balls is investigated experimentally in continously stratified fluid in a finite container. The oscillation frequency is found to be very close to the local Brunt-Vaisala frequency. The effect of added mass proves to be practically negligible. The evolution of rear jets is demonstrated, and a kind of long term levitation is found. We show

Diana C. Skigin, Hung Loui, Zoya Popovic, Edward F. Kuester

Phase resonances in transmission compound structures with subwavelength slits produce sharp dips in the transmission response. For all equal slits, the wavelengths of these sharp transmission minima can be varied by changing the width or the length of all the slits. In this paper we show that the width of the dip, i.e., the frequency range of minimum transmi

A. N. Artemyev, V. M. Shabaev, I. I. Tupitsyn, G. Plunien

We perform ab initio QED calculation of the (1s)^2(2s)^22p_{3/2} - (1s)^2(2s)^22p_{1/2} transition energy in the five-electron ion of argon. The calculation is carried out by perturbation theory starting with an effective screening potential approximation. Four different types of the screening potentials are considered. The rigorous QED calculations of the t

Paola Gori-Giorgi, Andreas Savin

The ``extended Overhauser model&#39;&#39; [Overhauser, Can. J. Phys. 1995, 73, 683] for the calculation of the spherically and system-averaged pair density (APD) has been recently combined with the Kohn-Sham equations to yield realistic APD and correlation energies. In this work we test this approach in the high-density (weakly-correlated) limit of the He is

Garcia de Andrade

Riemannian geometrical tools, such as Ricci collineations and Killing symmetries, so often used in Einstein general theory of gravitation are here applied to plasma physics to build magnetic surfaces from Einstein plasma metrics used in tokamak devices. It is shown that the Killing symmetries are constrains the Einstein magnetic surfaces while the Killing ve

Sachin Goyal, Noel C. Perkins

We simulate the nonlinear dynamic responses in Kirchhoff rod by including the important effects due to inertia and kinematic coupling of tension and torsion. We begin by reviewing a dynamic rod model of a strand (length of cable or DNA) in the form of a 12th order partial differential equation system. Numerical solutions reveal the effects of dynamics on cla

Sachin Goyal, Noel C. Perkins

It is well known that the structural deformations (stressed states) of DNA molecule play a crucial role in its biological functions including gene expression. For instance, looping in DNA (often mediated by protein binding) is a crucial step in many gene regulatory mechanisms. We use the mechanical rod model of DNA molecules to simulate its structural intera

Sachin Goyal, Noel C. Perkins, Christopher L. Lee

Marine cables under low tension and torsion on the sea floor can form highly contorted three-dimensional geometries that include loops (e.g. hockles) and tangles. These geometries arise from the conversion of torsional strain energy to bending strain energy or, kinematically, a conversion of twist to writhe. A dynamic form of Kirchhoff rod theory is reviewed

Sachin Goyal, Todd Lillian, Noel C. Perkins, Edgar Meyhofer

This paper introduces the use of cable dynamics models as a means to explore the mechanics of DNA on long-length scales. It is on these length scales that DNA forms twisted and curved three-dimensional shapes known as supercoils and loops. These long-length scale DNA structures have a pronounced influence on the functions of this molecule within the cell inc

Susanna Wilms, Francesco Giacosa, Dirk H. Rischke

We compute pion-nucleon scattering at tree-level within a gauged linear sigma model which contains the nucleon and its chiral partner. Such an investigation in principle allows to make definite predictions as to whether the main contribution to the nucleon mass comes from the chiral condensate or from the mixing with its chiral partner. We find that there se

M. Hasegawa, T. Mizusaki, K. Kaneko, Y. Sun

The long-standing problem of dramatic structure change near N=40 in Ge isotopes is investigated by means of large-scale shell model calculation. The analysis of simulated calculations suggests a possible understanding of the problem in terms of rapid increase in the $g_{9/2}$ proton and neutron occupation. The observed variation in excitation of the second $

M. Notani, H. Sakurai, N. Aoi, H. Iwasaki

The reaction mechanism of projectile fragmentation at intermediate energies has been investigated observing the target dependence of the production cross sections of very neutron-rich nuclei. Measurement of longitudinal momentum distributions of projectile-like fragments within a wide range of fragment mass and its charge was performed using a hundred-MeV/n

N. Grau

Two-particle azimuthal correlations have allowed detailed study of the modification to di-jets in the hot, dense medium created in RHIC collisions. Light can be shed by such correlations on many novel effects discovered at RHIC such as the enhanced p/pi ratio and conical structure of events with energy loss. Using pi0 triggers to reduce the effect of recombi

Jiangyong Jia

This is a status report on where PHENIX stands in terms of mapping out the landscape of jet correlation in $p_T$, hadron species, $\sqrt{s}$. We discuss separately high $p_T$ correlation results and low and intermediate $p_T$ correlation results. The former is sensitive to the quenching of the jet by medium, the later allows detailed study of the medium resp

Nino Boccara

We define and study a few properties of a class of random automata networks. While regular finite one-dimensional cellular automata are defined on periodic lattices, these automata networks, called randomized cellular automata, are defined on random directed graphs with constant out-degrees and evolve according to cellular automaton rules. For some families

Vladimir S. Novikov, Jing Ping Wang

We study a class of evolutionary partial differential systems with two components related to second order (in time) non-evolutionary equations of odd order in spatial variable. We develop the formal diagonalisation method in symbolic representation, which enables us to derive an explicit set of necessary conditions of existence of higher symmetries. Using th

David Bindel, Maciej Zworski

We consider one dimensional scattering and show how the presence of a mild positive barrier separating the interaction region from infinity implies that the bound and antibound states are symmetric modulo exponentially small errors in 1/h. This simple result was inspired by a numerical experiment and we describe the numerical scheme for an efficient computat

Roman Novikov, Vladimir Sharafutdinov

The polarization tomography problem consists of recovering a matrix function f from the fundamental matrix of the equation $Dη/dt=π_{\dotγ}fη$ known for every geodesic $γ$ of a given Riemannian metric. Here $π_{\dotγ}$ is the orthogonal projection onto the hyperplan $\dotγ^{\perp}$. The problem arises in optical tomography of slightly anisotropic media. The

V. P. Belavkin

Quantum mechanical systems exhibit an inherently probabilistic nature upon measurement which excludes in principle the singular direct observability continual case. Quantum theory of time continuous measurements and quantum prediction theory, developed by the author on the basis of an independent-increment model for quantum noise and nondemolition causality

Grigory Seregin, Wojciech Zajaczkowski

In the present paper, we prove a sufficient condition of local regularity for suitable weak solutions to the Navier-Stokes equations having axial symmetry. Our condition is an axially symmetric analog of the so-called $L_{3,\infty}$-case in the general local regularity theory.

Mathieu Stienon

We show how the classical Moser Lemma from symplectic geometry extends to generalized complex structures (GCS) on arbitrary Courant algebroids. For this, we extend the notion of Lie derivative to sections of the tensor bundle $(\otimes^i E)\otimes(\otimes^j E^*)$ with respect to sections of the Courant algebroid $E$ using the Dorfman bracket. We then give a

Patrick Guidotti

A modification of the Perona-Malik equation is proposed for which the local nonlinear diffusion term is replaced by a nonlocal term of slightly reduced ``strength&#39;&#39;. The new equation is globally well-posed (in spaces of classical regularity) and possesses desirable properties from the perspective of image processing. It admits characteristic function

Matias Luis del Hoyo, Elias Gabriel Minian

A global action is the algebraic analogue of a topological manifold. This construction was introduced in first place by A. Bak as a combinatorial approach to K-Theory and the concept was later generalized by Bak, Brown, Minian and Porter to the notion of groupoid atlas. In this paper we define and investigate homotopy invariants of global actions and groupoi

Robert C. Dalang, Davar Khoshnevisan, Eulalia Nualart

We consider a system of $d$ coupled non-linear stochastic heat equations in spatial dimension 1 driven by $d$-dimensional additive space-time white noise. We establish upper and lower bounds on hitting probabilities of the solution $\{u(t, x)\}_{t \in \mathbb{R}_+, x \in [0, 1]}$, in terms of respectively Hausdorff measure and Newtonian capacity. We also obt

Noëlle Bru, Laurence Despres, Christian Paroissin

We study two statistical models for short-length categorical (or ordinal) time series. The first one is a regression model based on generalized linear model. The second one is a parametrized Markovian model, particularizing the discrete autoregressive model to the case of categorical data. These models are used to analyze two data-sets: annual larch cone pro

François Golse, Francesco Salvarani

Consider the initial-boundary value problem for the 2-speed Carleman model of the Boltzmann equation of the kinetic theory of gases set in some bounded interval with boundary conditions prescribing the density of particles entering the interval. Under the usual parabolic scaling, a nonlinear diffusion limit is established for this problem. In fact, the techn

Hannes Leeb, Benedikt M. Pötscher

We consider the problem of estimating the conditional distribution of a post-model-selection estimator where the conditioning is on the selected model. The notion of a post-model-selection estimator here refers to the combined procedure resulting from first selecting a model (e.g., by a model selection criterion such as AIC or by a hypothesis testing procedu

Hongquan Xu

This paper considers the construction of minimum aberration (MA) blocked factorial designs. Based on coding theory, the concept of minimum moment aberration due to Xu [Statist. Sinica 13 (2003) 691--708] for unblocked designs is extended to blocked designs. The coding theory approach studies designs in a row-wise fashion and therefore links blocked designs w

Ursula U. Müller, Anton Schick, Wolfgang Wefelmeyer

Conditional expectations given past observations in stationary time series are usually estimated directly by kernel estimators, or by plugging in kernel estimators for transition densities. We show that, for linear and nonlinear autoregressive models driven by independent innovations, appropriate smoothed and weighted von Mises statistics of residuals estima

Pierre Ailliot, Emmanuel Frenod, Valerie Monbet

In this paper, we propose a new method to forecast the drift of objects in near coastal ocean on a period of several weeks. The proposed approach consists in estimating the probability of events linked to the drift using Monte Carlo simulations. It couples an averaging method which permits to decrease the computational cost and a statistical method in order

Oliver C. Schnürer, Felix Schulze

We consider a network in the Euclidean plane that consists of three distinct half-lines with common start points. From that network as initial condition, there exists a network that consists of three curves that all start at one point, where they form 120 degree angles, and expands homothetically under curve shortening flow. We also prove uniqueness of these

Farrukh Mukhamedov, José F. F. Mendes

In the paper we describe basin of attraction $p$-adic dynamical system $G(x)=(ax)^2(x+1)$. Moreover, we also describe the Siegel discs of the system, since the structure of the orbits of the system is related to the geometry of the $p$-adic Siegel discs.

J. Dony, D. M. Mason

In 1991 Stute introduced a class of estimators called conditional U-statistics. They can be seen as a generalization of the Nadaraya-Watson estimator, and their strong pointwise consistency to the general regression function has been obtained in the same paper by Stute. Very recently, Gine and Mason introduced the notion of a local U-process, which generaliz

J. Charles Gilbert

This note describes how the optimization problems of the Modulopt collection are organized within the Libopt environment. It is aimed at being a guide for using and enriching this collection in this environment.

Rémi Carles, Tohru Ozawa

We prove that for the mass critical nonlinear Schrodinger equations, the wave operators and their inverse are related explicitly in terms of the Fourier transform. We discuss some consequences of this property. In the one-dimensional case, we show a precise similarity between the mass critical nonlinear Schrodinger equation and a nonlinear Schrodinger equati

Timo Hanke

A splitting field of a central simple algebra is said to be absolute Galois if it is Galois over some fixed subfield of the centre of the algebra. The paper provides an existence theorem for such fields over global fields with enough roots of unity. As an application, all twisted function fields and all twisted Laurent series rings over symbol algebras (or p

Daniel Straumann, Thomas Mikosch

This paper studies the quasi-maximum-likelihood estimator (QMLE) in a general conditionally heteroscedastic time series model of multiplicative form $X_t=σ_tZ_t$, where the unobservable volatility $σ_t$ is a parametric function of $(X_{t-1},...,X_{t-p},σ_{t-1},... ,σ_{t-q})$ for some $p,q\ge0$, and $(Z_t)$ is standardized i.i.d. noise. We assume that these m

Mark Kambites

We study the relationship between the loop problem of a semigroup, and that of a Rees matrix construction (with or without zero) over the semigroup. This allows us to characterize exactly those completely zero-simple semigroups for which the loop problem is context-free. We also establish some results concerning loop problems for subsemigroups and Rees quoti

M. Gregoratti

We study the Classical Probability analogue of the dilations of a quantum dynamical semigroup in Quantum Probability. Given a (not necessarily homogeneous) Markov chain in discrete time in a finite state space E, we introduce a second system, an environment, and a deterministic invertible time-homogeneous global evolution of the system E with this environmen

Robert Nau

Incomplete preferences provide the epistemic foundation for models of imprecise subjective probabilities and utilities that are used in robust Bayesian analysis and in theories of bounded rationality. This paper presents a simple axiomatization of incomplete preferences and characterizes the shape of their representing sets of probabilities and utilities. De

Goulwen Fichou

We address the question of the classification under blow-Nash equivalence of simple Nash function germs. We state that this classification coincides with the real analytic classification. We prove moreover that a simple germ can not be blow-Nash equivalent to a nonsimple one. The method is based on the computation of relevant coefficients of the real zeta fu

Antoine Chaillet, Yacine Chitour, Antonio Loría, Mario Sigalotti

Consider the controlled system $dx/dt = Ax + α(t)Bu$ where the pair $(A,B)$ is stabilizable and $α(t)$ takes values in $[0,1]$ and is persistently exciting, i.e., there exist two positive constants $μ,T$ such that, for every $t\geq 0$, $\int_t^{t+T}α(s)ds\geq μ$. In particular, when $α(t)$ becomes zero the system dynamics switches to an uncontrollable system

Subhashis Ghosal, Anindya Roy

Consider binary observations whose response probability is an unknown smooth function of a set of covariates. Suppose that a prior on the response probability function is induced by a Gaussian process mapped to the unit interval through a link function. In this paper we study consistency of the resulting posterior distribution. If the covariance kernel has d

Yu Chuan Tai, Terence P. Speed

In this paper we derive one- and two-sample multivariate empirical Bayes statistics (the $\mathit{MB}$-statistics) to rank genes in order of interest from longitudinal replicated developmental microarray time course experiments. We first use conjugate priors to develop our one-sample multivariate empirical Bayes framework for the null hypothesis that the exp

Eitan Greenshtein

Let $(Y,X_1,...,X_m)$ be a random vector. It is desired to predict $Y$ based on $(X_1,...,X_m)$. Examples of prediction methods are regression, classification using logistic regression or separating hyperplanes, and so on. We consider the problem of best subset selection, and study it in the context $m=n^α$, $α>1$, where $n$ is the number of observations. We

Pascal Massart, Élodie Nédélec

We propose a general theorem providing upper bounds for the risk of an empirical risk minimizer (ERM).We essentially focus on the binary classification framework. We extend Tsybakov&#39;s analysis of the risk of an ERM under margin type conditions by using concentration inequalities for conveniently weighted empirical processes. This allows us to deal with w

T. Tony Cai, Mark G. Low

Adaptive estimation of a quadratic functional over both Besov and $L_p$ balls is considered. A collection of nonquadratic estimators are developed which have useful bias and variance properties over individual Besov and $L_p$ balls. An adaptive procedure is then constructed based on penalized maximization over this collection of nonquadratic estimators. This

W. Dunbar, S. Greenwald, J. McGowan, C. Searle

Let G, a subset of O(4), act isometrically on the 3-sphere. In this article we calculate a lower bound for the diameter of the quotient spaces $S^3/G$. We find it to be ${1/2}\arccos(\frac{\tan(\frac{3 π}{10})}{\sqrt3})$, which is exactly the value of the lower bound for diameters of the spherical space forms. In the process, we are also able to find a lower

Antonio Rojas-Leon, Daqing Wan

We study in detail the family of Calabi-Yau hypersurfaces defined by x_1+...+x_n+1/(x_1...x_n)=t over a finite field k. We determine its local and global monodromy and the trivial factors of its moment zeta function and Dwork&#39;s unit root zeta function.

Jan Kotanski

The four reggeized gluon states for non-vanishing Lorentz conformal spin $n_h$ are considered. To calculate their spectrum the Q-Baxter method is used. As a result we describe normalizable trajectory-like states, which form continuous spectrum, as well as discrete point-like solutions, which turn out to be non-normalizable. The point-like solutions exist due

Ludwik Turko

Finite volume corrections to higher moments are important observable quantities. They make possible to differentiate between different statistical ensembles even in the thermodynamic limit. It is shown that this property is a universal one. The classical grand canonical distribution is compared to the canonical distribution in the rigorous procedure of appro

Thomas W. Grimm, Albrecht Klemm, Marcos Marino, Marlene Weiss

We present a new method to solve the holomorphic anomaly equations governing the free energies of type B topological strings. The method is based on direct integration with respect to the non-holomorphic dependence of the amplitudes, and relies on the interplay between non-holomorphicity and modularity properties of the topological string amplitudes. We deve

M. N. Chernodub, V. I. Zakharov

Magnetic strings are defined as infinitely thin surfaces which are closed in the vacuum and can be open on an external monopole trajectory (that is, defined by &#39;t Hooft loop). We review briefly lattice data on the magnetic strings which refer mostly to SU(2) and SU(3) pure Yang-Mills theories and concentrate on implications of the strings for the Yang-Mi

S. Moretti, S. Munir, P. Poulose

The MSSM with explicit CP violation is studied through the di-photon decay channel of the lightest neutral Higgs boson. Through the leading one-loop order H1 --> gammar.gamma is affected by a large number of Higgs-sparticle couplings, which could be complex. Our preliminary scan over the Supersymmetric parameter space shows that more than 50% average deviati

Z. J. Ajaltouni, E. Di Salvo, O. Leitner

Weak decays of beauty baryons like Lambda_b into Lambda V(J^P=1^-), where the produced resonances are polarized, offer interesting opportunity to perform tests of Time-Reversal Invariance. This paper emphasizes the particular role of the resonance polarization-vectors and their physical properties by symmetry transformations. In particular, it is shown that

M. N. Ukhanov

Particles scattered off the nuclear target acquire a polarization if the nuclei have a non zero analyzing power. This effect is enhanced when particles traverse a bent crystal. Such enhancement under certain assumptions allows one to measure the analyzing power at the level of 10^-4 at the square of transfer momentum |t| < 10^-5 (GeV/c)2. If it happens that

Heiko Lacker

The most recent results from the B-factories on the time-dependent CP asymmetries measured in B0-decays mediated by b --> c c(bar) s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin2beta leads to a four-fold ambiguity on the unitarity triangle beta which can be reduced to a two-fold ambiguity by m

S. Stone

Updated CLEO results are presented for branching ratios and four-momentum transfer q^2 dependence of exclusive charmless semileptonic B decays, where the final state hadron is either a pi, rho, omega, eta or eta&#39;. These results have comparable accuracies with those of other experiments. We address the issue of flavor singlet couplings by limiting Gamma(B

S. Stone

I describe CLEO-c purely leptonic decay results leading to fD+=(222.6 +/- 16.7^{+2.8}_{-3.4}) MeV, fDs+=(280.1 +/- 11.6 +/- 6.0) MeV, and fDs+/fD+=1.26 +/- 0.11 +/-0.03. Form-factor measurements in Cabibbo favored and suppressed pseudoscalar decays are presented. Some comparisons are made with theoretical predictions.

Winston Fairbairn, Etera R. Livine

An effective field theory for matter coupled to three-dimensional quantum gravity was recently derived in the context of spinfoam models in hep-th/0512113. In this paper, we show how this relates to group field theories and generalized matrix models. In the first part, we realize that the effective field theory can be recasted as a matrix model where couplin

Jannie A. Leach, Peter K. S. Dunsby, Sante Carloni

We consider the case of $R^n$-gravity and perform a detailed analysis of the dynamics in Bianchi I cosmologies which exhibit {\it local rotational symmetry} (LRS). We find exact solutions and study their behaviour and stability in terms of the values of the parameter $n$. In particular, we found a set of cosmic histories in which the universe is initially is

Dennis M. Wilkinson, Bernardo A. Huberman

Since its inception six years ago, the online encyclopedia Wikipedia has accumulated 6.40 million articles and 250 million edits, contributed in a predominantly undirected and haphazard fashion by 5.77 million unvetted volunteers. Despite the apparent lack of order, the 50 million edits by 4.8 million contributors to the 1.5 million articles in the English-l

Tor Helleseth, Alexander Kholosha, Geir Jarle Ness

Considered is the distribution of the crosscorrelation between $m$-sequences of length $2^m-1$, where $m=2k$, and $m$-sequences of shorter length $2^k-1$. New pairs of $m$-sequences with three-valued crosscorrelation are found and the complete correlation distribution is determined. Finally, we conjecture that there are no more cases with a three-valued cros

J. Jalden, B. Ottersten

Zhang et. al. recently derived upper and lower bounds on the achievable diversity of an N_R x N_T i.i.d. Rayleigh fading multiple antenna system using transmit antenna selection, spatial multiplexing and a linear receiver structure. For the case of L = 2 transmitting (out of N_T available) antennas the bounds are tight and therefore specify the maximal diver