December 2006 arXiv papers — page 35

S. Bonnabel, Ph. Martin, P. Rouchon

This paper presents three non-linear observers on three examples of engineering interest: a chemical reactor, a non-holonomic car, and an inertial navigation system. For each example, the design is based on physical symmetries. This motivates the theoretical development of invariant observers, i.e, symmetry-preserving observers. We consider an observer to co

Gert Aarts, Justin Foley

In order to enhance our understanding of spectral functions in lattice QCD obtained with the help of the Maximum Entropy Method, we study meson spectral functions for lattice fermions with chiral symmetry. In particular we analyse lattice artefacts for standard overlap, overlap hypercube and domain wall fermions in the free field limit. We also present first

Kazuhiro Yamamoto, Masaki Ando, Keita Kawabe, Kimio Tsubono

We modified the modal expansion, which is the traditional method used to calculate thermal noise. This advanced modal expansion provides physical insight about the discrepancy between the actual thermal noise caused by inhomogeneously distributed loss and the traditional modal expansion. This discrepancy comes from correlations between the thermal fluctuatio

Guang Cheng, Michael R. Kosorok

In this paper, inference for the parametric component of a semiparametric model based on sampling from the posterior profile distribution is thoroughly investigated from the frequentist viewpoint. The higher-order validity of the profile sampler obtained in Cheng and Kosorok [Ann. Statist. 36 (2008)] is extended to semiparametric models in which the infinite

Luca Dall'Asta, Claudio Castellano

The role of memory is crucial in determining the properties of many dynamical processes in statistical physics. We show that the simple addition of memory, in the form of noise reduction, modifies the overall scaling behavior of the voter model, introducing an effective surface tension analogous to that recently observed in memory-based models of social dyna

N. Brouzakis, N. Tetradis, E. Tzavara

We study the form of the luminosity distance as a function of redshift in the presence of large scale inhomogeneities, with sizes of order 10 Mpc or larger. We approximate the Universe through the Swiss-cheese model, with each spherical region described by the Tolman-Bondi metric. We study the propagation of light beams in this background, assuming that the

M. J. Reid, K. M. Menten, S. Trippe, T. Ott

In the first two papers of this series, we determined the position of Sgr A* on infrared images, by aligning the positions of red giant stars with positions measured at radio wavelengths for their circumstellar SiO masers. In this paper, we report detections of 5 new stellar SiO masers within 50" (2 pc) of Sgr A* and new and/or improved positions and pro

Shashank Bhatnagar, Shi-Yuan Li

We employ the framework of Bethe-Salpeter equation under Covariant Instantaneous Ansatz to study the leptonic decays of pseudoscalar mesons. The Dirac structure of hadron-quark vertex function $Γ$ is generalized to include various Dirac covariants besides $γ_5 $ from their complete set. The covariants are incorporated in accordance with a power counting rule

M. Gazdzicki

A new experiemntal program to study hadron production in hadron-nucleus and nucleus-nucleus collisions at the CERN SPS has been recently proposed by the NA49-future collaboration. The physics goals of the program are: (i) search for the critical point of strongly interacting matter and a study of the properties of the onset of deconfinemnt in nucleus-nucleus

Gor Sarkissian

We study Cardy states in the (2,2,2,2) Gepner model from the algebraic and geometric sides. We present the full list of primaries of this model together with their characters. The effects of fixed point resolution are analyzed. Annulus partition function between various Cardy states are calculated. Using the equivalent description in terms of $T^4/Z_4$ the c

Lawrence Taylor

We study the problem of defining line bundles over certain non-Hausdorff spaces known as Quantum Tori, motivated by the proposed theory of Real Multiplication for real quadratic fields. We draw analogies from the theory of Line Bundles over Complex Tori to define a non-trivial cohomological notion of Line Bundles over Quantum Tori. We prove a structure theor

Jong-Phil Lee

It is argued that there is a fundamental momentum cutoff in heavy-to-light transitions, which is caused by possible Cherenkov gluon radiation when an energetic light parton travels through the ''brown muck''. The soft-overlap contributions where the partonic momenta configuration is highly asymmetric are disfavored, and the problematic end-po

Peter Kuchment, Olaf Post

An explicit derivation of dispersion relations and spectra for periodic Schrödinger operators on carbon nano-structures (including graphen and all types of single-wall nano-tubes) is provided.

Lawrence Taylor

We explore the possibility of using Model Theoretic ideas to study certain non-Hausdorff spaces knwon as Quantum Tori with a view to their application to Manin's theory of Real Multiplication. We study the morphisms between these spaces using Nonstandard Analysis, and describe an action of a certain Galois group on a certain classes of these spaces.

Cheoljun Eom, Gabjin Oh, Seunghwan Kim

We investigate a factor that can affect the number of links of a specific stock in a network between stocks created by the minimal spanning tree (MST) method, by using individual stock data listed on the S&P500 and KOSPI. Among the common factors mentioned in the arbitrage pricing model (APM), widely acknowledged in the financial field, a representative mark

Patricia Ball, Gareth W. Jones, Roman Zwicky

We calculate the main observables in $B_{u,d}\to (ρ,ω,K^*)γ$ and $B_s\to (\bar K^*,ϕ)γ$ decays, i.e. branching ratios and CP and isospin asymmetries. We include QCD factorisation results and also the dominant contributions beyond QCD factorisation, namely long-distance photon emission and soft-gluon emission from quark loops. All contributions beyond QCD fac

Marie-Amelie Morlais

In this paper, we consider the classical problem of utility maximization in a financial market allowing jumps. Assuming that the constraint set is a compact set, rather than a convex one, we use a dynamic method from which we derive a specific BSDE. We then aim at showing existence and uniqueness results for the introduced BSDE. This allows us to give an exp

T. Meunier, K-J. Tielrooij, I. T. Vink, F. H. L. Koppens

We demonstrate experimentally a read-out method that distinguishes between two-electron spin states in a quantum dot. This scheme combines the advantages of the two existing mechanisms for spin-to-charge conversion with single-shot charge detection: a large difference in energy between the two states and a large difference in tunnel rate between the states a

Martin Markl

We show how the machine of PROP profiles invented by S. Merkulov can be used to study and classify natural operators in differential geometry. We also give an interpretation of graph complexes arising in this context in terms of representation theory. As application, we prove several results on classification of natural operators acting on vector fields and

B. P. Venemans, R. G. McMahon, S. J. Warren, E. A. Gonzalez-Solares

We present the initial results from our search for high redshift, z > 6, quasars using near infrared data from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Our analysis of 106 deg^2 of sky from Data Release 1 (DR1) has resulted in the discovery of ULAS J020332.38+001229.2, a luminous (J_AB=20.0, J_Vega=19.1, M_1450=-26.2) quasar at z=

Biswajoy Brahmachari, Nobuchika Okada

In an economical system with only two heavy right handed neutrinos, we postulate a new texture for $3 \times 2$ Dirac mass matrix $m_D$. This model implies one massless light neutrino and thus displays only two patterns of mass spectrum for light neutrinos, namely hierarchical or inverse-hierarchical. Both the cases can correctly reproduce all the current ne

Serge Florens, Pascal Simon, Sabine Andergassen, Denis Feinberg

We investigate the influence of an electromagnetic environment, characterized by a finite impedance $Z(ω)$, on the Kondo effect in quantum dots. The circuit voltage fluctuations couple to charge fluctuations in the dot and influence the spin exchange processes transferring charge between the electrodes. We discuss how the low-energy properties of a Kondo qua

Wen Zhao

In this paper, we improve the calculation of the relic gravitational waves (RGW) in two aspects: First, we investigate the transfer function after considering the redshift-suppression effect, the accelerating expansion effect, the damping effect of free-streaming relativistic particles, and the damping effect of cosmic phase transition, and give a simple app

Jae-Weon Lee, DoYong Kwon, Jaewan Kim

From the NP-hardness of the quantum separability problem and the relation between bipartite entanglement and the secret key correlations, it is shown that the problem deciding whether a given quantum state has secret correlations in it or not is in NP-complete.

C. Liu, J. Hu, H. Newberg, Y. Zhao

Sloan Digital Sky Survey (SDSS) DR5 photometric data with $120^{\circ} < α< 270^{\circ}$, $25^{\circ} < δ< 70^{\circ}$ are searched for new Milky Way companions or substructures in the Galactic halo. Five candidates are identified as overdensities of faint stellar sources that have color-magnitude diagrams similar to those of known globular clusters or dwarf

Daniel Grether, Charles H. Lineweaver

We examine the relationship between the frequency of close companions (stellar and planetary companions with orbital periods < 5 years) and the metallicity of their Sun-like (~ FGK) hosts. We confirm and quantify a ~4 sigma positive correlation between host metallicity and planetary companions. We find little or no dependence on spectral type or distance in

L. Mathey, A. Polkovnikov, A. H. Castro Neto

We study the phase-locking transition of two coupled low-dimensional superfluids, either two-dimensional superfluids at finite temperature, or one-dimensional superfluids at zero temperature. We find that the superfluids have a strong tendency to phase-lock. The phase-locking is accompanied by a sizeable increase of the transition temperature $T_{c}$ (in 2D

Orfeu Bertolami

We reminisce on the first steps of the cosmology community in Portugal, which can be traced back to about 20 years ago, and discuss its achievements and current specificities. We also reflect on the aspirations, hopes and challenges for the future.

V. N. Soshnikov

In the spirit of continued study of general plasma wave properties we investigated the boundary problem with the simplest form of electric field pulse at the edge x=0 of half-infinite uniform plasma slab with Maxwellian electron distribution function. In the case of longitudinal electric field pulse its traveling velocity is essentially other than in the cas

Yu-Qi Chen, Tao Han, Zong-Guo Si

We evaluate the cross section for single slepton production at hadron colliders in supersymmetric theories with R-parity violating interactions to the next-to-leading order in QCD. We obtain fully differential cross section by using the phase space slicing method. We also perform soft-gluon resummation to all order in $α_s$ of leading logarithm to obtain a c

Dijana Jakelic, Adriano Moura

We study finite-dimensional representations of hyper loop algebras, i.e., the hyperalgebras over an algebraically closed field of positive characteristic associated to the loop algebra over a complex finite-dimensional simple Lie algebra. The main results are the classification of the irreducible modules, a version of Steinberg&#39;s Tensor Product Theorem,

Animesh Datta, Steven T. Flammia, Anil Shaji, Carlton M. Caves

Entanglement measures constructed from two positive, but not completely positive maps on density operators are used as constraints in placing bounds on the entanglement of formation, the tangle, and the concurrence of 4 x N mixed states. The maps are the partial transpose map and the $Φ$-map introduced by Breuer [H.-P. Breuer, Phys. Rev. Lett. 97, 080501 (20

A. I. Solomon, G. E. H. Duchamp, P. Blasiak, A. Horzela

Recent elegant work on the structure of Perturbative Quantum Field Theory (PQFT) has revealed an astonishing interplay between analysis(Riemann Zeta functions), topology (Knot theory), combinatorial graph theory (Feynman Diagrams) and algebra (Hopf structure). The difficulty inherent in the complexities of a fully-fledged field theory such as PQFT means that

Thomas Salzburger, Helmut Ritsch

We study the quantum dynamics of an ultracold atomic gas in a deep optical lattice within an optical high-$Q$ resonator. The atoms are coherently illuminated with the cavity resonance tuned to a blue vibrational sideband, so that photon scattering to the resonator mode is accompanied by vibrational cooling of the atoms. This system exhibits a threshold above

J. Kiukas, P. Lahti

In accordance with the fact that quantum measurements are described in terms of positive operator measures (POMs), we consider certain aspects of a quantization scheme in which a classical variable $f:\R^2\to \R$ is associated with a unique positive operator measure (POM) $E^f$, which is not necessarily projection valued. The motivation for such a scheme com

Gen Kimura, Hajime Tanaka, Masanao Ozawa

Conventional solutions to the (Mean) King&#39;s problem without using entanglement have been investigated by Aravind [P. K. Aravind, ``Best conventional solutions to the King&#39;s problem&#39;&#39;, Z. Naturforsch. 58a, 682 (2003)]. We report that the upper bound for the success probability claimed there is not valid in general, and give a condition for the

P. D. Bruza, D. Widdows, John Woods

This chapter is offered as a contribution to the logic of down below. We attempt to demonstrate that the nature of human agency necessitates that there actually be such a logic. The ensuing sections develop the suggestion that cognition down below has a structure strikingly similar to the physical structure of quantum states. In its general form, this is not

J. M. A. Figueiredo

Present quantum Monte Carlo codes use statistical techniques adapted to find the amplitude of a quantum system or the associated eigenvalues. Thus, they do not use a true physical random source. It is demonstrated that, in fact, quantum probability admits a description based on a specific class of random process at least for the single particle case. Then a

Vladislav Volman, Eshel Ben-Jacob, Herbert Levine

We present a simple biophysical model for the coupling between synaptic transmission and the local calcium concentration on an enveloping astrocytic domain. This interaction enables the astrocyte to modulate the information flow from presynaptic to postsynaptic cells in a manner dependent on previous activity at this and other nearby synapses. Our model sugg

C. Costa Santos, J. Bernardes, P. Vitanyi, L. Antunes

Fetal heart rate (FHR) monitoring, before and during labor, is a very important medical practice in the detection of fetuses in danger. We clustered FHR tracings by compression in order to identify abnormal ones. We use a recently introduced approach based on algorithmic information theory, a theoretical, rigorous and well-studied notion of information conte

D. Stauffer, C. Schulze, K. Rohde

We use the Chowdhury ecosystem model, one of the most complex agent-based ecological models, to test the latitude-niche breadth hypothesis, with regard to habitat width, i.e., whether tropical species generally have narrower habitats than high latitude ones. Application of the model has given realistic results in previous studies on latitudinal gradients in

Hidenori Kimura, Hiroyuki Okano, Reiko J. Tanaka

Binding and unbinding of ligands to specific sites of a macromolecule are one of the most elementary molecular interactions inside the cell that embody the computational processes of biological regulations. The interaction between transcription factors and the operators of genes and that between ligands and binding sites of allosteric enzymes are typical exa

Nicolas Paul, Luc Fety, Michel Terre

This paper deals with the estimation of the modes of an univariate mixture when the number of components is known and when the component density are well separated. We propose an algorithm based on the minimization of the &#34;kp&#34; criterion we introduced in a previous work. In this paper we show that the global minimum of this criterion can be reached wi

Massimo Tessarotto, Marco Ellero, Necdet Aslan, Michael Mond

In this paper the issue of the determination of the fluid pressure in incompressible fluids is addressed, with particular reference to the search of algorithms which permit to advance in time the fluid pressure without actually solving numerically the Poisson equation. Based on an inverse kinetic approach recently proposed for the incompressible Navier-Stoke

M. J. Wright, J. A. Pechkis, J. L. Carini, S. Kallush

We demonstrate the ability to coherently control ultracold atomic Rb collisions using frequency-chirped light on the nanosecond time scale. For certain center frequencies of the chirp, the rate of inelastic trap-loss collisions induced by negatively chirped light is dramatically suppressed compared to the case of a positive chirp. We attribute this to a fund

P. Zijlstra, K. L. van der Molen, A. P. Mosk

We propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. We demonstrate the use of the dye embedded in the microsphere as an internal broadband excitation source, thus eliminating the need for a tunable excitation source. We measured the full width at half maximum of

Anjan Kumar Chandra, Kamalika Basu Hajra, Pratap Kumar Das, Parongama Sen

The collaboration network is an example of a social network which has both non-trivial temporal and spatial dependence. Based on the observations of collaborations in Physical Review Letters, a model of collaboration network is proposed which correctly reproduces the time evolution of the link length distributions, clustering coefficients, degree distributio

Mari Watanabe, Mark Alford, Raphael Schneider, Axel Bauer

Background: It has been difficult to demonstrate circadian rhythm in the two parameters of heart rate turbulence, turbulence onset (TO) and turbulence slope (TS). Objective: To devise a new method for detecting circadian rhythm in noisy data, and apply it to selected Holter recordings from two post-myocardial infarction databases, Cardiac Arrhythmia Suppress

Y. Hayashi, J. Matsukubo

In a topological structure affected by geographical constraints on liking, the connectivity is weakened by constructing local stubs with small cycles, a something of randomness to bridge them is crucial for the robust network design. In this paper, we numerically investigate the effects of adding shortcuts on the robustness in geographical scale-free network

M. S. Bhagwat, C. D. Roberts

A strongly momentum-dependent dressed-quark mass function is basic to QCD. It is central to the appearance of a constituent-quark mass-scale and an existential prerequisite for Goldstone modes. Dyson-Schwinger equation (DSE) studies have long emphasised these facts and are a natural way to exploit them.

A. A. Raduta, C. M. Raduta

The Gamow-Teller transition operator is written as a polynomial in the dipole proton-neutron and quadrupole charge conserving QRPA boson operators, using the prescription of the boson expansion technique of Belyaev-Zelevinski type. Then, the $2νββ$ process ending on the first $2^+$ state in the daughter nucleus is allowed via one, two and three boson states

Qingfeng Li, Marcus Bleicher, Xianglei Zhu, Horst Stoecker

Based on the UrQMD transport model, the transverse momentum and the rapidity dependence of the Hanbury-Brown-Twiss (HBT) radii $R_L$, $R_O$, $R_S$ as well as the cross term $R_{OL}$ at SPS energies are investigated and compared with the experimental NA49 and CERES data. The rapidity dependence of the $R_L$, $R_O$, $R_S$ is weak while the $R_{OL}$ is signific

W. Horiuchi, Y. Suzuki, B. Abu-Ibrahim, A. Kohama

We systematically analyze total reaction cross sections of carbon isotopes with N=6--16 on a $^{12}$C target for wide range of incident energy. The intrinsic structure of the carbon isotope is described by a Slater determinant generated from a phenomenological mean-field potential, which reasonably well reproduces the ground state properties for most of the

E. R. Tardiff, J. A. Behr, T. E. Chupp, K. Gulyuz

Investigations of the polarization and relaxation of $^{209}$Rn by spin exchange with laser optically pumped rubidium are reported. On the order of one million atoms per shot were collected in coated and uncoated glass cells. Gamma-ray anisotropies were measured as a signal of the alignment (second order moment of the polarization) resulting from the combina

Imran A Butt, Jonathan A D Wattis

We consider a two-dimensional Fermi-Pasta-Ulam (FPU) lattice with hexagonal symmetry. Using asymptotic methods based on small amplitude ansatz, at third order we obtain a reduction to a cubic nonlinear Schrodinger equation (NLS) for the breather envelope. However, this does not support stable soliton solutions, so we pursue a higher-order analysis yielding a

Ozlem Defterli, Dumitru Baleanu

The recently modified Faddeev-Jackiw formalism for systems having one chain of four levels of only second-class constraints is applied to the non-trivial a=1 bosonized chiral Schwinger model in (1+1) dimensions as well as to one mechanical system. The sets of obtained constraints are in agreement with Dirac&#39;s canonical formulation.

Dumitru Baleanu, Om P. Agrawal

In this paper we develop a fractional Hamiltonian formulation for dynamic systems defined in terms of fractional Caputo derivatives. Expressions for fractional canonical momenta and fractional canonical Hamiltonian are given, and a set of fractional Hamiltonian equations are obtained. Using an example, it is shown that the canonical fractional Hamiltonian an

Dumitru Baleanu, Sami I. Muslih, Kenan Tas

The fractional Hamiltonian analysis of 1+1 dimensional field theory is investigated and the fractional Ostrogradski&#39;s formulation is obtained. The fractional path integral of both simple harmonic oscillator with an acceleration-squares part and a damped oscillator are analyzed. The classical results are obtained when fractional derivatives are replaced w

I. V. Drozdov, A. A. Stahlhofen

The classical far field concept of wave velocities has its merits while exibiting intrinsic difficulties. A general local approach for the definition of velocities and especially phase velocities for waves avoiding these difficulties is proposed. It includes the classical definitions as particular cases and can be applied to waves of an arbitrary structure,

M. Samuelides, B. Cessac

This paper is a review dealing with the study of large size random recurrent neural networks. The connection weights are selected according to a probability law and it is possible to predict the network dynamics at a macroscopic scale using an averaging principle. After a first introductory section, the section 1 reviews the various models from the points of

E. Defez, A. Hervas, L. Soler, M. M. Tung

This paper presents the non-linear generalization of a previous work on matrix differential models. It focusses on the construction of approximate solutions of first-order matrix differential equations Y&#39;(x)=f(x,Y(x)) using matrix-cubic splines. An estimation of the approximation error, an algorithm for its implementation and illustrative examples for Sy

Javier Fernandez de Bobadilla, Maria Pe Pereira

We look at topological equisingularity of a holomorphic family of reduced mapping germs f_t:(C^3,O)->C over a contractible base T having non-isolated singularities, by means of their normalisations. We introduce the notion of Equisingularity at the Normalisation for a family f_t and prove that, in many cases, it characterises topological embedded equisingula

Joseph D. Masters, William Menasco, Xingru Zhang

We use Heegaard splittings to give a criterion for a tunnel number one knot manifold to be non-fibered and to have large cyclic covers. We also show that such a knot manifold (satisfying the criterion) admits infinitely many virtually Haken Dehn fillings. Using a computer, we apply this criterion to the 2 generator, non-fibered knot manifolds in the cusped S

C. P. Hughes, A. Nikeghbali, M. Yor

We prove a multidimensional extension of Selberg&#39;s central limit theorem for the logarithm of the Riemann zeta function on the critical line. The limit is a totally disordered process, whose coordinates are all independent and Gaussian.

Jean Bourgain, Gady Kozma

We construct an example of two continuous maps f and g of the circle to itself with the same absolute value of the Fourier transform but with different winding numbers, answering a question of Brezis.

Lawrence Taylor

Previously we developed a nontrivial notion of line bundles over Quantum Tori. In this text we study sections of these line bundles leading to a study concerning theta functions for Quantum Tori. We prove the existence of such meromorphic theta functions, and view their application in the context of Stark&#39;s conjectures and Hilbert&#39;s twelfth problem.

Javier López Peña, Gabriel Navarro

We give an explicit description of the set of all factorization structures, or twisting maps, existing between the algebras k^2 and k^2, and classify the resulting algebras up to isomorphism. In the process we relate several different approaches formerly taken to deal with this problem, filling a gap that appeared in a recent paper by Cibils. We also provide

Eli Bagno, David Garber, Toufik Mansour

We define the excedance number on the complex reflection groups and compute its multidistribution with the number of fixed points on the set of involutions in these groups. We use some recurrence formulas and generating functions manipulations to obtain our results.

Shihoko Ishii

In this paper we introduce a maximal divisorial set in the arc space of a variety. The generalized Nash problem is reduced to a translation problem of the inclusion of two maximal divisorial sets. We study this problem and show a counter example to the most natural expectation even for a non-singular variety.

Laura Geatti, Andrea Iannuzzi, Jean-Jacques Loeb

We present a family of examples of two dimensional, hyperbolic complex manifolds whose envelopes of holomorphy are not hyperbolic.

Tian-Jun Li

Symplectic 4-manifolds with Kodaira dimension zero can be viewed as symplectic Calabi-Yau surfaces. We are able to completely determine their Betti numbers by proving two general results on quaternionic vector bundles.

Mark Burgin, Oktay Duman

Statistical convergence was introduced in connection with problems of series summation. The main idea of the statistical convergence of a sequence l is that the majority of elements from l converge and we do not care what is going on with other elements. We show (Section 2) that being mathematically formalized the concept of statistical convergence is direct

Ievgen Bondarenko, Rostislav Grigorchuk, Rostyslav Kravchenko, Yevgen Muntyan

An approach to a classification of groups generated by 3-state automata over a 2-letter alphabet and the current progress in this direction are presented. Several results related to the whole class are formulated. In particular, all finite, abelian, and free groups are classified. In addition, we provide detailed information and complete proofs for several g

Tamer Oraby

To analyze the limiting spectral distribution of some random block-matrices, Girko [Girko, 2000] uses a system of canonical equations from [Girko, 98]. In this paper, we use the method of moments to give an integral form for the almost sure limiting spectral distribution of such matrices.

T. Byczkowski, M. Ryznar, J. Malecki

The purpose of this paper is to find explicit formulas for basic objects pertaining the local potential theory of the operator $(I-Δ)^{α/2}$, $0<α<2$. The potential theory of this operator is based on Bessel potentials $J_α=(I-Δ)^{-α/2}$. We compute the {\it harmonic measure} of the half-space and write a concise form of the corresponding {\it Green function

James Demmel, Ioana Dumitriu, Olga Holtz, Robert Kleinberg

We perform forward error analysis for a large class of recursive matrix multiplication algorithms in the spirit of [D. Bini and G. Lotti, Stability of fast algorithms for matrix multiplication, Numer. Math. 36 (1980), 63--72]. As a consequence of our analysis, we show that the exponent of matrix multiplication (the optimal running time) can be achieved by nu

Gavril Farkas

We describe a systematic way of constructing effective divisors on the moduli space of stable curves of genus g having exceptionally small slope. We prove that any divisor on \bar{M}_g consisting of curves failing a certain Green-Lazarsfeld syzygy type condition, provides a counterexample to the Harris-Morrison Slope Conjecture. These divisors generalize our

W. Mueckenheim

Transfinite set theory including the axiom of choice supplies the following basic theorems: (1) Mappings between infinite sets can always be completed, such that at least one of the sets is exhausted. (2) The real numbers can be well ordered. (3) In a finite set of real numbers the maximum below a given limit can always be determined. (4) Any two different r

Guangcun Lu

We introduce the concept of pseudo symplectic capacities which is a mild generalization of that of symplectic capacities. As a generalization of the Hofer-Zehnder capacity we construct a Hofer-Zehnder type pseudo symplectic capacity and estimate it in terms of Gromov-Witten invariants. The (pseudo) symplectic capacities of Grassmannians and some product symp

Branko Dragovich

Adelic quantum mechanics is form invariant under an interchange of real and p-adic number fields as well as rings of p-adic integers. We also show that in adelic quantum mechanics Feynman&#39;s path integrals for quadratic actions with rational coefficients are invariant under changes of their entries within nonzero rational numbers.

Pawel Klimas

The recently found shock wave solution in the scalar field model with the field potential $V(ϕ)=|ϕ|$ is generalized to the case $V(ϕ)=|ϕ|-{1/2}λϕ^2$. We find two kinds of the shock waves, which are analogous of compression and expansion waves. The dependence of the waves on the parameter $λ$ is investigated in detail.

Par Arvidsson, Robert Marnelius

Conformal theories in a d dimensional spacetime may be expressed as manifestly conformal theories in a d+2 dimensional conformal space as first proposed by Dirac. The reduction to d dimensions goes via the d+1 dimensional hypercone in the conformal space. Here we give a rather extensive expose of such theories. We review and extend the theory of spinning con

Katherine Freese, James T. Liu, Douglas Spolyar

Chain inflation takes place in the string theory landscape as the universe tunnels rapidly through a series of ever lower energy vacua such as may be characterized by quantized changes in four form fluxes. The string landscape may be well suited to an early period of rapid tunneling, as required by chain inflation, followed by a later period of slow tunnelin

J. T. de Santana Amaral, M. A. Betemps, M. B. Gay Ducati, G. Soyez

We reproduce the DIS measurements of the proton structure function at high energy from the dipole model in momentum space. To model the dipole-proton forward scattering amplitude, we use the knowledge of asymptotic solutions of the Balitsky-Kovchegov equation, describing high-energy QCD in the presence of saturation effects. We compare our results with the p

Ivone F. M. Albuquerque

In supersymmetric theories where the lightest supersymmetric particle is the gravitino the next to lightest supersymmetric particle (NLSP) is typically a long lived charged slepton. These NLSPs can be produced by high energy neutrinos interactions with nucleons in the Earth and be detected by km$^3$ neutrino telescopes. The signal, consists of two parallel c

A. Prokudin, C. Turk

The recent data on the transverse single spin asymmetry $A_{UT}^{\sin(ϕ_h+ϕ_S)}$ from HERMES and COMPASS Collaborations are analysed within LO parton model with unintegrated parton distribution and fragmentation functions. A fit of SIDIS data from HERMES Collaboration is performed leading to the extraction of favoured and unfavoured Collins fragmentation fun

Peter J. S. Watson

A number of authors have considered potential models for hybrid mesons. These frequently involve approximating the vibrating flux-tube by a set of beads, and making an adiabatic approximation which gives rise to a static inter-quark potential which has an effective repulsive 1/r potential. We show that this approximation is almost certainly wrong. Since the

Tamas S. Biro, Andras Laszlo, Peter Van

We prove that a temperature independent mass distribution is identically zero below a mass threshold (mass gap) value, if the pressure satisfies certain inequalities. This supports the finding of a minimal mass in quark matter equation of state by numerical estimates and by substitution of analytic formulas. We present a few inequalities for the mass distrib

A. A. Osipov, B. Hiller, J. Moreira, A. H. Blin

It is shown that eight-quark interactions, which are needed to stabilize the ground state of the combined three flavor Nambu -- Jona-Lasinio and &#39;t Hooft Lagrangians, play also an important role in determining the critical temperature at which transitions occur from the dynamically broken chiral phase to the symmetric phase.

Xiao-Gang He

The tetrahedron $A_4$ group has been widely used in studying neutrino mixing matrix. It provides a natural framework of model building for the tri-bimaximal mixing matrix. In this class of models, it is necessary to have two Higgs fields, $χ$ and $χ&#39;$, transforming under $A_4$ as 3 with one of them having vacuum expectation values for the three component

M. Y. Hussein

We review the status of theoretical calculations relevant for electroweak physics at hadron colliders. The large parton flux at high energy gives rise to events where different pairs of partons interact contemporarily with large momentum exchange. We present calculations of the cross-section for two, three and four weak gauge bosons production in single and

G. Battistoni, M. V. Garzelli, E. Gadioli, S. Muraro

FLUKA is a general purpose Monte Carlo transport and interaction code used for fundamental physics and for a wide range of applications. These include Cosmic Ray Physics (muons, neutrinos, EAS, underground physics), both for basic research and applied studies in space and atmospheric flight dosimetry and radiation damage. A review of the hadronic models avai

R. Narayanan, H. Neuberger

In the planar limit, in the deconfined phase, the Euclidean Dirac operator has a spectral gap around zero. We show that functions of eigenvalues close to the spectral edge, which are independent of common rescalings and shifts gauge configuration by gauge configuration, have distributions described by a Gaussian Hermitian matrix model. However, combinations

CDF II Collaboration

We present a measurement of the fractions F_0 and F_+ of longitudinally polarized and right-handed W bosons in top quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 318 pb -1. We select ttbar candidate events with one lepton, at least four jets, and missing t

Michael Bradley, Daniel Eriksson, Gyula Fodor, Istvan Racz

The second order perturbative field equations for slowly and rigidly rotating perfect fluid balls of Petrov type D are solved numerically. It is found that all the slowly and rigidly rotating perfect fluid balls up to second order, irrespective of Petrov type, may be matched to a possibly non-asymptotically flat stationary axisymmetric vacuum exterior. The P

Thomas Bäckdahl

In this paper, the problem of finding an axisymmetric stationary spacetime from a specified set of multipole moments, is studied. The condition on the multipole moments, for existence of a solution, is formulated as a convergence condition on a power series formed from the multipole moments. The methods in this paper can also be used to give approximate solu

F. Rahaman, A. Ghosh, M. Kalam

Long ago, since 1951, Lyra proposed a modification of Riemannian geometry. Based on the Lyra&#39;s modification on Riemannian geometry, Sen and Dunn constructed a field equation which is analogous to Einstein&#39;s field equations. Further more, Sen and Dunn gave series type solution to the static vacuum field equations. Retaining only a few terms, we have s

Kouji Nakamura

The second order perturbations in Friedmann-Robertson-Walker universe filled with a perfect fluid are completely formulated in the gauge invariant manner without any gauge fixing. All components of the Einstein equations are derived neglecting the first order vector and tensor modes. These equations imply that the tensor and the vector mode of the second ord

Kristina Lerman, Laurie Jones

The new social media sites - blogs, wikis, del.icio.us and Flickr, among others - underscore the transformation of the Web to a participatory medium in which users are actively creating, evaluating and distributing information. The photo-sharing site Flickr, for example, allows users to upload photographs, view photos created by others, comment on those phot

Kristina Lerman

The new social media sites -- blogs, wikis, Flickr and Digg, among others -- underscore the transformation of the Web to a participatory medium in which users are actively creating, evaluating and distributing information. Digg is a social news aggregator which allows users to submit links to, vote on and discuss news stories. Each day Digg selects a handful