December 2006 arXiv papers — page 32

Antongiulio Fornasiero, Marcello Mamino

We study the set of Dedekind cuts over a linearly ordered Abelian group as a structure over the language (0,<,+,-). Moreover, we obtain a simple set of axioms for the universal part of the theory of such structures. Finally, we prove that every structure satisfying the given axioms is a sub-structure of the set of cuts over a suitable group.

Hellen Colman

We propose a notion of 1-homotopy for generalized maps. This notion generalizes those of natural transformation and ordinary homotopy for functors. The 1-homotopy type of a Lie groupoid is shown to be invariant under Morita equivalence. As an application we consider orbifolds as groupoids and study the notion of orbifold 1-homotopy type induced by a 1-homoto

Cornelia Drutu

This paper overviews recent developments in the classification up to quasi-isometry of finitely generated groups, and more specifically of relatively hyperbolic groups.

A. S. Martins, Timothy B. Boykin, Gerhard Klimeck, Belita Koiller

A tight-binding parametrization for silicon, optimized to correctly reproduce effective masses as well as the reciprocal space positions of the conduction-band minima, is presented. The reliability of the proposed parametrization is assessed by performing systematic comparisons between the descriptions of donor impurities in Si using this parametrization and

Liang Kong

Let $V$ be a vertex operator algebra satisfying certain reductivity and finiteness conditions such that $\mathcal{C}_V$, the category of V-modules, is a modular tensor category. We study open-closed field algebras over V equipped with nondegenerate invariant bilinear forms for both open and closed sectors. We show that they give algebras over certain $\C$-ex

B. Nikolic, R. M. Prestage, D. S. Balser, C. J. Chandler

We describe phase-retrieval holography measurements of the 100-m diameter Green Bank Telescope using astronomical sources and an astronomical receiver operating at a wavelength of 7 mm. We use the technique with parameterization of the aperture in terms of Zernike polynomials and employing a large defocus, as described by Nikolic, Hills & Richer (2006). Indi

Zhi-Yong Wang, Cai-Dong Xiong, Bing He

A relativistic quantum-mechanical description of guided waves is given, based on which we present an alternative way to describe and interpret the propagation of electromagnetic wave packets through an undersized waveguide. In particular, we show that the superluminal phenomenon of evanescent modes is actually a known conclusion in quantum field theory, and

S. L. Lyakhovich, A. A. Sharapov

We discuss a recently proposed method of quantizing general non-Lagrangian gauge theories. The method can be implemented in many different ways, in particular, it can employ a conversion procedure that turns an original non-Lagrangian field theory in $d$ dimensions into an equivalent Lagrangian topological field theory in $d+1$ dimensions. The method involve

Sagar Chakraborty, Debabrata Dutta

We numerically study some of the 3-D dynamical systems which exhibit complete synchronisation as well as generalised synchronisation (GS) to show that these systems can be conveniently partitioned into equivalent classes facilitating the study of bifurcation diagrams (BDs) within each class. We demonstrate how BDs may be helpful in assessing the robustness o

An Min Wang

We first rewrite the perturbation expansion of the time evolution operator [An Min Wang, quant-ph/0611216] in a form as concise as possible. Then we derive out the perturbation expansion of the time-dependent complete Green operator and prove that it is just the Fourier transformation of the Dyson equation. Moreover, we obtain the perturbation expansion of t

Xiao-Gang He, Tzu-Chiang Yuan

We study glueball G production in gluonic penguin decay B -> X_s G, using next-to-leading order b -> s g^* gluonic penguin interaction and an effective coupling of a glueball to two gluons. The effective coupling allows us to study the decay rate of a glueball to two pseudoscalars in the framework of chiral perturbation theory. Identifying the f_0(1710) to b

V. A. Kuz&#39;menko

R. Ionicioiu in arXiv:1012.0647 claims that beam-splitters do not have memory. This is the unproved statement. From other side, such small quantum objects as molecules, atoms and even photons have memory, which is connected with the inequality of forward and reversed processes in quantum physics.

Lorenzo Iorio

In this paper we directly constrain possible spatial variations of the Newtonian gravitational constant G over ranges 0.01-5 AU in various extrasolar multi-planet systems. By means of the third Kepler&#39;s law we determine the quantity Γ_ XY=G_X/G_Y for each couple of planets X and Y located at different distances from their parent star: deviations of the m

Gavril Farkas

This is a survey written for the Proceedings of the AMS Summer Institute in Algebraic Geometry held in Seattle in 2005. Topics discussed in the survey include the ample and the effective cone of the moduli space of curves, Kodaira dimension, Slope Conjecture, log canonical models etc.

Daoyuan Fang, Chengbo Wang

By using the Strichartz esitmate and Picard iteration, we prove the subcritical(critical in some cases) global solution in $C_t H_x^s\cap C_t^1 H^{s-1}_x$ with small data for semilinear wave equation with nonlinearity of type $(\partial u)^k$($k\ge 1+\frac{4}{n-1}\vee 2$ and $(n,k)\neq (3,3)$). For $(n,k)=(3,3)$, we get the almost global existence. In additi

Hongki Min, B. R. Sahu, Sanjay K. Banerjee, A. H. MacDonald

We study the gate voltage induced gap that occurs in graphene bilayers using \textit{ab initio} density functional theory. Our calculations confirm the qualitative picture suggested by phenomenological tight-binding and continuum models. We discuss enhanced screening of the external interlayer potential at small gate voltages, which is more pronounced in the

Francesco Calogero, Matteo Sommacal

A class of solvable (systems of) nonlinear evolution PDEs in multidimensional space is discussed. We focus on a rotation-invariant system of PDEs of Schrödinger type and on a relativistically-invariant system of PDEs of Klein-Gordon type. Isochronous variants of these evolution PDEs are also considered.

Bin-Bin Zhang, En-Wei Liang, Bing Zhang

An early steep decay component following the prompt GRBs is commonly observed in {\em Swift} XRT light curves, which is regarded as the tail emission of the prompt gamma-rays. Prompted by the observed strong spectral evolution in the tails of GRBs 060218 and 060614, we present a systematic time-resolved spectral analysis for the {\em Swift} GRB tails detecte

Dmitry Jakobson, Iosif Polterovich, John A. Toth

We obtain an estimate from below for the remainder in Weyl&#39;s law on negatively curved surfaces. In the constant curvature case, such a bound was proved independently by Hejhal and Randol in 1976 using the Selberg zeta function techniques. Our approach works in arbitrary negative curvature, and is based on wave trace asymptotics for long times, equidistri

Christopher M. Graney

The question of annual stellar parallax is usually viewed as having been a "win-win situation" for seventeenth-century astronomers who subscribed to the Copernican view of universe in which the Earth orbits the Sun and the Sun is one of many suns (the fixed stars) scattered throughout space. Detecting parallax would be solid evidence for the Earth's motion,

Lieven Clarisse

PhD thesis (University of York). The thesis covers in a unified way the material presented in quant-ph/0403073, quant-ph/0502040, quant-ph/0504160, quant-ph/0510035, quant-ph/0512012 and quant-ph/0603283. It includes two large review chapters on entanglement and distillation.

Guang Ping He

Recently an attack strategy was proposed by Chau [H. F. Chau, quant-ph/0602099 v3], which was claimed to be able to break all quantum string seal protocols, including the one proposed by He [G. P. He, Int. J. Quant. Inform. 4, 677 (2006)]. Here it will be shown that the information obtained in He&#39;s protocol by the attack is trivial. Thus Chau&#39;s concl

Baris I. Erkmen, Jeffrey H. Shapiro

We provide a unified treatment of classical and quantum Gaussian-state sources that unambiguously identifies which features of ghost imaging are strictly quantum mechanical. We show that ghost-image formation is fundamentally classical, with the image being expressible in terms of the phase-insensitive and phase-sensitive cross correlations between the detec

E. P. Furlani, Y. Sahoo, K. C. Ng, J. C. Wortman

A model is presented for predicting the capture of magnetic micro/nano-particles in a bioseparation microsystem. This bioseparator consists of an array of conductive elements embedded beneath a rectangular microfluidic channel. The magnetic particles are introduced into the microchannel in solution, and are attracted and held by the magnetic force produced b

V. Dorobantu

It is an approach to introduce the forward Kolmogorov equation as an interesting natural ingredient in studying the evolution of the market stock prices.

A. Sarkar, P. Barat

The heart beat data recorded from samples before and during meditation are analyzed using two different scaling analysis methods. These analyses revealed that mediation severely affects the long range correlation of heart beat of a normal heart. Moreover, it is found that meditation induces periodic behavior in the heart beat. The complexity of the heart rat

Laszlo Erdos, Benjamin Schlein, Horng-Tzer Yau

The time dependent Gross-Pitaevskii equation describes the dynamics of initially trapped Bose-Einstein condensates. We present a rigorous proof of this fact starting from a many-body bosonic Schroedinger equation with a short scale repulsive interaction in the dilute limit. Our proof shows the persistence of an explicit short scale correlation structure in t

James P Kelliher

We say that the solution u to the Navier-Stokes equations converges to a solution v to the Euler equations in the vanishing viscosity limit if u converges to v in the energy norm uniformly over a finite time interval. Working specifically in the unit disk, we show that a necessary and sufficient condition for the vanishing viscosity limit to hold is the vani

Bjorn Poonen, Jose Felipe Voloch

We prove that for a large class of subvarieties of abelian varieties over global function fields, the Brauer-Manin condition on adelic points cuts out exactly the rational points. This result is obtained from more general results concerning the intersection of the adelic points of a subvariety with the adelic closure of the group of rational points of the ab

M. Anoussis, D. Gatzouras

Let $G$ be a semi-direct product $G=A\times_ϕK$ with $A$ Abelian and $K$ compact. We characterize spread-out probability measures on $G$ that are mixing by convolutions by means of their Fourier transforms. A key tool is a spectral radius formula for the Fourier transform of a regular Borel measure on $G$ that we develop, and which is analogous to the well-k

Bilal Chanane

In this work, we use the \textit{regularized sampling method} to compute the eigenvalues of Sturm Liouville problems with discontinuity conditions inside a finite interval. We work out an example by computing a few eigenvalues and their corresponding eigenfunctions.

Bilal Chanane

This paper deals with the computation of the eigenvalues of non self-adjoint Sturm-Liouville problems with parameter dependent boundary conditions using the \textit{regularized sampling method}. A few numerical examples among which singular ones will be presented to illustrate the merit of the method and comparison made with the exact eigenvalues when they a

Nicolas Bouleau, Christophe Chorro

This article proposes a link between statistics and the theory of Dirichlet forms used to compute errors. The error calculus based on Dirichlet forms is an extension of classical Gauss&#39; approach to error propagation. The aim of this paper is to derive error structures from measurements. The links with Fisher&#39;s information lay the foundations of a str

Gabriel Minian, Miguel Ottina

We develop the theory of CW(A)-complexes, which generalizes the classical theory of CW-complexes, keeping the geometric intuition of J.H.C. Whitehead&#39;s original theory. We obtain this way generalizations of classical results, such as Whitehead Theorem, which allow a deeper insight in the homotopy properties of these spaces.

Vladislav Vysotsky

Consider a particle moving through a random medium, which consists of spherical obstacles, randomly distributed in R^d. The particle is accelerated by a constant external field; when colliding with an obstacle, the particle inelastically reflects. We study the asymptotics of X(t), which denotes the position of the particle at time t, as t tends to infinity.

Victor Ivrii

I consider 4-dimensional Schrödinger operator with the generic non-degenerating magnetic field and for a generic potential I derive spectral asymptotics with the remainder estimate $O(μ^{-1}h^{-3})$ and the principal part $\asymp h^{-4}$ where $h\ll 1$ is Planck constant and $μ\gg 1$ is the intensity of the magnetic field. For general potentials remainder es

Chad M. Schafer, Kjell A. Doksum

This paper considers multiple regression procedures for analyzing the relationship between a response variable and a vector of covariates in a nonparametric setting where both tuning parameters and the number of covariates need to be selected. We introduce an approach which handles the dilemma that with high dimensional data the sparsity of data in regions o

Yevgeniy Kovchegov

We consider a multi-particle generalization of linear edge-reinforced random walk (ERRW). We observe that in absence of exchangeability, new techniques are needed in order to study the multi-particle model. We describe an unusual coupling construction associated with the two-point edge-reinforced process on Z and prove a form of recurrence: the two particles

Thorsten Renk, Jorg Ruppert

Previous dilepton measurements in heavy-ion collisions have mainly focused on invariant mass spectra to clarify in-medium changes of vector meson properties. However, a dimuon is characterized by two scales -- invariant mass $M$ and transverse momentum $p_T$. Like transverse momentum spectra of hadrons, $p_T$ spectra of dileptons arise from an interplay betw

H. Leutwyler

Recent developments in low energy pion physics are reviewed, emphasizing the strength of dispersion theory in this context. As an illustration of the method, I discuss some consequences of the forward dispersion relation obeyed by the isoscalar component of the scattering amplitude.

Kh. M. Beshtoev

It is shown that if weak interactions can generate masses and polarize matter, then the Cherenkov effect induced by these interactions appears. The resonance ($v_ν< c/n$) and the Cherenkov ($v_ν> c/n$) effects are competitive processes and at definite neutrino energies the resonance effect will change to the Cherenkov effect and we obtain an excellent possib

I. P. Lokhtin, A. M. Snigirev

The model to simulate jet quenching effect in ultrarelativistic heavy ion collisions is presented. The model is the fast Monte-Carlo tool implemented to modify a standard PYTHIA jet event. The model has been generalized to the case of the &#34;full&#34; heavy ion event (the superposition of soft, hydro-type state and hard multi-jets) using a simple and fast

Daniel Stefankovic, Santosh Vempala, Eric Vigoda

We present a near-optimal reduction from approximately counting the cardinality of a discrete set to approximately sampling elements of the set. An important application of our work is to approximating the partition function $Z$ of a discrete system, such as the Ising model, matchings or colorings of a graph. The typical approach to estimating the partition

G. H. Fecher, C. Felser

This work reports about electronic structure calculations for the Heusler compound Co$_2$FeAl$_{1-x}$Si$_x$. Particular emphasis was put on the role of the main group element in this compound. The substitution of Al by Si leads to an increase of the number of valence electrons with increasing Si content and may be seen as electron-doping. Self-consistent ele

I. V. Bobkova, A. M. Bobkov

The theory of the I-V characteristics in diffusive superconductor/weak ferromagnet/superconductor (SFS) junction is developed. We show that the exchange field $h$ of the ferromagnet manifests itself as an additional conductance peak at $eV \sim Δ+h$ in the phase-coherent regime, when the Thouless energy is of the order of superconducting order parameter. The

A. Sarkar, P. Barat

We present a continuous time random walk model for the Portevin-Le Chatelier (PLC) effect. From our result it is shown that the dynamics of the PLC band can be explained in terms of the Levy Walk.

S. K. Pandey, S. Khalid, A. V. Pimpale

The transition metal K-edge x-ray absorption near edge structure (XANES) studies have been carried on LaBO3 (B=Mn, Fe, Co, Ni), La2CuO4 and SrMnO3 compounds. The theoretical spectra have been calculated using transition metal (TM) 4p density of states (DOS) obtained from full-potential LMTO density functional theory. The exchange-correlation functional used

Argyro Tasitsiomi

I review some results on the galaxy/light-mass connection obtained by dissipationless simulations in combination with a simple, non-parametric model to connect halo circular velocity to the luminosity of the galaxy they would host. I focus on the galaxy-mass correlation and mass-to-light ratios obtained from galaxy up to cluster scales. The predictions of th

R. Benton Metcalf, Joseph Silk

We use the distribution, and particularly the skewness, of high redshift type Ia supernovae brightnesses relative to the low redshift sample to constrain the density of macroscopic compact objects (MCOs) in the universe. The data favors dark matter made of microscopic particles (such as the LSP) at 89% confidence. Future data will greatly improve this limit.

Martin E. Beer, Lynnette M. Dray, Andrew R. King, Graham A. Wynn

We investigate the evolution of interacting binaries where the donor star is a low-mass giant more massive than its companion. It is usual to assume that such systems undergo common-envelope (CE) evolution, where the orbital energy is used to eject the donor envelope, thus producing a closer binary or a merger. We suggest instead that because mass transfer i

V. Berezinsky, A. Gazizov, M. Kachelrieß

We discuss as a new signature for the interaction of extragalactic ultrahigh energy protons with cosmic microwave background radiation a spectral feature located at $E=6.3\times 10^{19}$ eV in the form of a narrow and shallow dip. It is produced by the interference of $e^+e^-$-pair and pion production. We show that this dip and in particular its position are

P. Q. Hung

In this talk, I will present highlights of a recent model of dark energy and dark matter in which the present universe is ``trapped&#39;&#39; in a {\em false vacuum} described by the potential of an axion-like scalar field (the acceleron) which is related to a new strong interaction gauge sector, $SU(2)_Z$, characterized by a scale $Λ_Z \sim 3 \times 10^{-3}

Jennifer L. Hoffman

Supernovae of type IIn possess spectral signatures that indicate an intense interaction between the supernova ejecta and surrounding dense circumstellar material cast off by the star in pre-explosion mass-loss episodes. Studying this interaction can yield clues to the nature of Type IIn progenitors and their mass loss history. In particular, polarization spe

A. V. Dodonov, S. S. Mizrahi, V. V. Dodonov

We examine some aspects of the continuous photodetection model for photocounting processes in cavities. First, we work out a microscopic model that describes the field-detector interaction and deduce a general expression for the Quantum Jump Superoperator (QJS), that shapes the detector&#39;s post-action on the field upon a detection. We show that in particu

Randall A. LaViolette, Lory A. Ellebracht, Charles J. Gieseler

Agents are represented by nodes on a random graph (e.g., small world or truncated power law). Each agent is endowed with a zero-mean random value that may be either positive or negative. All agents attempt to find relief, i.e., to reduce the magnitude of that initial value, to zero if possible, through exchanges. The exchange occurs only between agents that

Saharon Shelah

We show the consistency of the set of regular cardinals which are the character of some ultrafilter on omega is not convex. We also deal with the set of pi chi-characters of ultrafilters on omega.

B. Nikolic, R. E. Hills, J. S. Richer

We present a technique for the accurate estimation of large-scale errors in an antenna surface using astronomical sources and detectors. The technique requires several out-of-focus images of a compact source and the signal-to-noise ratio needs to be good but not unreasonably high. For a given pattern of surface errors, the expected form of such images can be

Douglas M. Gingrich

The cross section for black hole production in hadron colliders is calculated using a factorization hypothesis in which the parton-level process is integrated over the parton density functions of the protons. The mass, spin, charge, colour, and finite size of the partons are usually ignored. We examine the effects of parton electric charge on black hole prod

I. S. Krivenko, A. N. Rubtsov

A new algorithm for analytic continuation of noisy quantum Monte Carlo (QMC) data from the Matsubara domain to real frequencies is proposed. Unlike the widely used maximum-entropy (MaxEnt) procedure, our method is linear with respect to input data and can therefore be applied to off-diagonal components of a thermal Green&#39;s function, or to a self-energy f

P. Thalmeier, A. Langari

The anisotropic Kondo necklace model in 2D and 3D is treated as a genuine model for magnetic to Kondo singlet quantum phase transitions in the heavy fermion (HF) compounds. The variation of the quantum critical point (QCP) with anisotropy parameters has been investigated previously in the zero field case [1]. Here we extend the treatment to finite fields usi

G. Chaudhuri, S. Das Gupta

Many calculations for the production of light and intermediate particles resulting from heavy ion collisions at intermediate energies exist. Calculations of properties of the largest fragment resulting from multifragmentation are rare. In this paper we compute these properties and compare them with the data for the case of gold on carbon. We use the canonica

Adriano Tomassini, Luigi Vezzoni

We consider a generalization of Calabi-Yau structures in the context of $α$-Sasakian manifolds. We study deformations of a special class of Legendrian submanifolds and classify invariant contact Calabi-Yau structures on 5-dimensional nilmanifolds. Finally we generalize to codimension $r$.

Jae-Hyun Yang

This is the lecture note of my invited lecture given at the International Conference on Number Theory at Harish-Chandra Research Institute in Allahabad (quite near the River Ganges), India on December 5, 2006. I gave an invited lecture on the same subject at Department of Mathematics, Kyoto University, Japan on June 23, 2009. The new lecture note contains mo

Sabine Andergassen, Tilman Enss, Christoph Karrasch, Volker Meden

The functional renormalization group provides an efficient description of the interplay and competition of correlations on different energy scales in interacting Fermi systems. An exact hierarchy of flow equations yields the gradual evolution from a microscopic model Hamiltonian to the effective action as a function of a continuously decreasing energy cutoff

Shunsuke Furukawa, Gregoire Misguich

A characterization of topological order in terms of bi-partite entanglement was proposed recently [A. Kitaev and J. Preskill, Phys. Rev. Lett. 96, 110404 (2006); M. Levin and X.-G. Wen, ibid, 110405]. It was argued that in a topological phase there is a universal additive constant in the entanglement entropy, called the topological entanglement entropy, whic

G. Crasta, A. Malusa

We consider a system of PDEs of Monge-Kantorovich type arising from models in granular matter theory and in electrodynamics of hard superconductors. The existence of a solution of such system (in a regular open domain $\Omega\subset\mathbb{R}^n$), whose construction is based on an asymmetric Minkowski distance from the boundary of $\Omega$, was already estab

G. Crasta, A. Malusa

Let the space $\mathbb{R}^n$ be endowed with a Minkowski structure $M$ (that is $M\colon \mathbb{R}^n \to [0,+\infty)$ is the gauge function of a compact convex set having the origin as an interior point, and with boundary of class $C^2$), and let $d^M(x,y)$ be the (asymmetric) distance associated to $M$. Given an open domain $\Omega\subset\mathbb{R}^n$ of c

Vyacheslav M. Abramov

The paper studies closed queueing networks containing a server station and $k$ client stations. The server station is an infinite server queueing system, and client stations are single-server queueing systems with autonomous service, i.e. every client station serves customers (units) only at random instants generated by a strictly stationary and ergodic sequ

S. Dev, Sanjeev Kumar, Surender Verma, Shivani Gupta

The generic predictions of two-texture zero neutrino mass matrices in the flavor basis have been examined especially in relation to the degeneracies between mass matrices within a class and interesting constraints on the neutrino parameters have been obtained. It is shown that the knowledge of the octant of $θ_{23}$, the sign of $\cosδ$ and neutrino mass hie

S. Moghimi-Araghi, A. Nejati

The Abelian Sandpile Model (ASM) is a paradigm of self-organized criticality (SOC) which is related to $c=-2$ conformal field theory. The conformal fields corresponding to some height clusters have been suggested before. Here we derive the first corrections to such fields, in a field theoretical approach, when the lattice parameter is non-vanishing and consi

Ling-Lie Chau

I formulate expressions for amplitudes suitable for quantifying both modulus and phase direct CP violations. They result in Möbius transformation (MT) relations, which provide encouraging information for the search of direct CP violations in general. I apply the formulation to calculate the measurements of phase direct CP violations and strong amplitudes in

Robert Oeckl

We give an introductory account of the general boundary formulation of quantum theory. We refine its probability interpretation and emphasize a conceptual and historical perspective. We give motivations from quantum gravity and illustrate them with a scenario for describing gravitons in quantum gravity.

Song Lin, Fei Gao, Fen-Zhuo Guo, Qiao-Yan Wen

In a recent paper [Z. J. Zhang and Z. X. Man, Phys. Rev. A 72, 022303(2005)], a multiparty quantum secret sharing protocol based on entanglement swapping was presented. However, as we show, this protocol is insecure in the sense that an unauthorized agent group can recover the secret from the dealer. Hence, we propose an improved version of this protocol whi

Robert A. Herrmann

In this paper, all of the restrictions that were previously required in order to obtain a hyperfinite unification for a set of physical theories have been removed. This yields the ultimate hyperfinite ultralogic unification for any set of physical theories.

G. Kamuntavicius, A. Masalaite, S. Mickevicius, D. Germanas

A method for the calculation of translationally invariant wave functions for systems of identical fermions with arbitrary potential of pair interaction is developed. It is based on the well-known result that the essential dynamic part of the Hamiltonian for the system of identical particles is the Reduced Hamiltonian operator describing relative movement of

K. Kashiwa, H. Kouno, T. Sakaguchi, M. Matsuzaki

The chiral phase transition and color superconductivity in an extended NJL model with eight-quark interactions are studied. The scalar-type nonlinear term hastens the chiral phase transition,the scalar-vector mixing term suppresses effects of the vector-type linear term and the scalar-diquark mixing term makes the coexisting phase wider.

Junko Yamagata, Satoru Hirenzaki

We considered the kaon absorption from atomic states into nucleus. We found that the nuclear density probed by the atomic kaon significantly depends on the kaon orbit. Then, we reexamined the meanings of the observed strengths of one-body and two-body kaon absorption, and investigated the effects to the formation spectra of kaon bound states by in-flight ($K

Kenneth M. Nollett, Steven C. Pieper, R. B. Wiringa, J. Carlson

We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We find that a good three-nucleon interaction is crucial to obtain an accurate description of neutron-alpha scattering.

Carlos Lourenco

In my (&#34;not a summary&#34;) talk at the Hard Probes 2006 conference, I gave &#34;a personal and surely biased view on only a few of the many open questions on quarkonium and electromagnetic probes&#34;. Some of the points reported in that talk are exposed in this paper, having in mind the most important of all the open questions: do we have, today, from

Shimon Garti, Saharon Shelah

We deal here with colorings of the pair (mu^+, mu), when mu is a strong limit and singular cardinal. We show that there exists a coloring c, with no refinement. It follows, that the properties of identities of (mu^+, mu) when mu is singular, differ in an essential way from the case of regular mu .

Pierre Matet, Saharon Shelah

Let kappa be a regular uncountable cardinal and lambda > kappa a singular strong limit cardinal. We give a new characterization of the nonstationary subsets of P_kappa (lambda) and use this to prove that the nonstationary ideal on P_kappa (lambda) is nowhere precipitous.

Chanoch Havlin, Saharon Shelah

We prove the existence of pairs of models of the same cardinality lambda which are very equivalent according to EF games, but not isomorphic. We continue the paper math.LO/0404222, but we don&#39;t rely on it.

Gabor Sagi, Saharon Shelah

We show that there is a restriction, or modification of the finite-variable fragments of First Order Logic in which a weak form of Craig&#39;s Interpolation Theorem holds, but a strong form of this theorem does not hold. Translating these results into Algebraic Logic we obtain a finitely axiomatizable subvariety of finite dimensional Representable Cylindric

Saharon Shelah

Let mu be singular of uncountable cofinality. If mu>2^{cf(mu)}, we prove that in P=([mu]^mu,supseteq) as a forcing notion we have a natural complete embedding of Levy(aleph_0, mu^+) (so P collapses mu^+ to aleph_0) and even Levy(aleph_0, U_{J^{bd}_kappa}(mu)) . The ``natural&#39;&#39; means that the forcing ({p in [mu]^mu :p closed}, supseteq) is naturally e

S. Fournais, B. Helffer

We reconsider the elliptic estimates for magnetic operators in two and three dimensions used in connection with Ginzburg-Landau theory. Furthermore we discuss the so-called blow-up technique in order to obtain optimal estimates in the limiting cases.

Saharon Shelah, Lutz Strüngmann

We show that it is consistent with ordinary set theory ZFC and the generalized continuum hypothesis that there exist two separable abelian groups of cardinality aleph_1 which are filtration equivalent and one is a Whitehead group but the other is not. This solves one of the open problems of Eklof and Mekler.

Fausto Cavalli, Giovanni Naldi, Gabriella Puppo, Matteo Semplice

The application of Runge-Kutta schemes designed to enjoy a large region of absolute stability can significantly increase the efficiency of numerical methods for PDEs based on a method of lines approach. In this work we investigate the improvement in the efficiency of the time integration of relaxation schemes for degenerate diffusion problems, using SSP Rung

Fausto Cavalli, Matteo Semplice

Different relaxation approximations to partial differential equations, including conservation laws, Hamilton-Jacobi equations, convection-diffusion problems, gas dynamics problems, have been recently proposed. The present paper focuses onto diffusive relaxed schemes for the numerical approximation of nonlinear reaction diffusion equations. High order methods

Gengsheng Wang

In this paper, we study a time optimal internal control problem governed by the heat equation in $Ω\times [0,\infty)$. In the problem, the target set $S$ is nonempty in $L^2(Ω)$, the control set $U$ is closed, bounded and nonempty in $L^2(Ω)$ and control functions are taken from the set $\uad=\{u(\cdot, t): [0,\infty)\ra L^2(Ω) {measurable}; u(\cdot, t)\in U

Fausto Cavalli, Giovanni Naldi, Gabriella Puppo, Matteo Semplice

In this work we compare two semidiscrete schemes for the solution of hyperbolic conservation laws, namely the relaxation and the Kurganov Tadmor central scheme. We are particularly interested in their behavior under small time steps, in view of future applications to convection diffusion problems. The schemes are tested on two benchmark problems, with one sp

Antongiulio Fornasiero

Let No be Conway&#39;s class of surreal numbers. I will make explicit the notion of a function f on No recursively defined over some family of functions. Under some &#34;tameness&#34; and uniformity condition, f must satisfy some interesting properties; in particular, the supremum of the class of element greater or equal to a fixed d in No is actually an ele

Iasson Karafyllis, Costas Kravaris

In this work sufficient conditions expressed by means of single and vector Lyapunov functions of Uniform Input-to-Output Stability (UIOS) and Uniform Input-to-State Stability (UISS) are given for finite-dimensional systems under feedback control with zero order hold.

Frederic A. B. Edoukou

We study the functional codes $C_h(X)$ defined by G. Lachaud in $\lbrack 10 \rbrack$ where $X \subset {\mathbb{P}}^N$ is an algebraic projective variety of degree $d$ and dimension $m$. When $X$ is a hermitian surface in $PG(3,q)$, Sørensen in \lbrack 15\rbrack, has conjectured for $h\le t$ (where $q=t^2$) the following result : $$# X_{Z(f)}(\mathbb{F}_{q})

Frederic A. B. Edoukou

We study the functional codes of second order defined by G. Lachaud on $\mathcal{X} \subset {\mathbb{P}}^4(\mathbb{F}_q)$ a quadric of rank($\mathcal{X}$)=3,4,5 or a non-degenerate hermitian variety. We give some bounds for %$# \mathcal{X}_{Z(\mathcal{Q})}(\mathbb{F}_{q})$, the number of points of quadratic sections of $\mathcal{X}$, which are the best possi

Manfred Truemper

An operational approach to the Collatz Conjecture is presented. Scenarios are defined as strings of characters &#34;s&#34; (for &#34;spike&#34;) and &#34;d&#34; (for &#34;down&#34;) which symbolize the Collatz operations (3m+1)/2 and m/2 in a Collatz Series connecting two odd integers, the startnumber and the endnumber. It is shown that a scenario determines

U. A. Rozikov, U. U. Jamilov

In this paper we introduce a notion of $F-$ quadratic stochastic operator. For a wide class of such operators we show that each operator of the class has unique fixed point. Also we prove that any trajectory of the $F$-quadratic stochastic operator converges to the fixed point exponentially fast.

Kentaro Saji, Masaaki Umehara, Kotaro Yamada

We shall introduce the singular curvature function on cuspidal edges of surfaces, which is related to the Gauss-Bonnet formula and which characterizes the shape of cuspidal edges. Moreover, it is closely related to the behavior of the Gaussian curvature of a surface near cuspidal edges and swallowtails.

S. Gulzari, Y. N. Srivastava, J. Swain, A. Widom

We show that QED radiative corrections change the propagator of a charged Dirac particle so that it acquires a fractional anomalous exponent connected with the fine structure constant. The result is a nonlocal object which represents a particle with a roughened trajectory whose fractal dimension can be calculated. This represents a significant shift from the

W. F. Kao

Existence and stability analysis of the Kantowski-Sachs type universe in a higher derivative induced gravity theory is studied in details. Existence of one stable mode and one unstable mode is shown to be in favor of the inflationary universe. As a result, the de Sitter background can be made to be stable against anisotropic perturbations with proper constra

V. M. Red&#39;kov

Possible quantum mechanical corollaries of changing the vectorial geometrical model of the physical space, extending it twice, in order to describe its spinor structure (in other terminology and emphasis it is known as the Hopf&#39;s bundle) are investigated. The extending procedure is realized in cylindrical parabolic coordinates. It is done through expansi