January 2003 arXiv papers

Jacqueline Chen, Andrey V. Kravtsov, Charles R. Keeton

Multiply-imaged quasar lenses can be used to constrain the substructure mass fraction in galaxy-sized dark matter halos via anomalous flux ratios in lensed images. The flux ratios, however, can be affected by both the substructure in the lens halo and by isolated small-mass halos along the entire line-of-sight to the lensed source. While lensing by dark matt

Rava A. da Silveira, Mehran Kardar

We consider generalizations of the Kardar--Parisi--Zhang equation that accomodate spatial anisotropies and the coupled evolution of several fields, and focus on their symmetries and non-perturbative properties. In particular, we derive generalized fluctuation--dissipation conditions on the form of the (non-linear) equations for the realization of a Gaussian

A. G. Ramm

An integral-differential equation is derived for the self-consistent (effective) field in the medium consisting of many small bodies randomly distributed in some region. Acoustic and electromagnetic fields are considered in such a medium. Each body has a characteristic dimension $a\llλ$, where $λ$ is the wavelength in the free space. The minimal distance $d$

E. Abdalla, K. H. C. Castello-Branco, A. Lima-Santos

We consider quasi-extreme Kerr and quasi-extreme Schwarzschild-de Sitter black holes. From the known analytical expressions obtained for their quasi-normal modes frequencies, we suggest an area quantization prescription for those objects.

S. Shresta, B. L. Hu

The reduced dynamics of an atomic qubit coupled both to its own quantized center of mass motion through the spatial mode functions of the electromagnetic field, as well as the vacuum modes, is calculated in the influence functional formalism. The formalism chosen can describe the entangled non-Markovian evolution of the system with a full account of the cohe

Cem Yuce

In this article, the problem of the charged harmonic plus an inverse harmonic oscillator with time-dependent mass and frequency in a time-dependent electromagnetic field is investigated. It is reduced to the problem of the inverse harmonic oscillator with time-independent parameters and the exact wave function is obtained.

N. G. Deshpande, Dilip Kumar Ghosh

The models of large extra compact dimensions, as suggested by Arkani-Hamed, Dimopoulos and Dvali, predict exciting phenomenological consequences with gravitational interactions becoming strong at the TeV scale. Such theories can be tested at the existing and future colliders. In this paper, we study the contribution of virtual Kaluza-Klein excitations (both

Martin Howard, Martin van Hecke

We study the spatiotemporally chaotic dynamics of holes and defects in the 1D complex Ginzburg--Landau equation (CGLE). We focus particularly on the self--disordering dynamics of holes and on the variation in defect profiles. By enforcing identical defect profiles and/or smooth plane wave backgrounds, we are able to sensitively probe the causes of the spatio

J. Paetzold, M. Bashkanov, R. Bilger, W. Brodowski

Exclusive measurements of the p p -> p p pi+ pi- reaction have been carried out at Tp = 775 MeV at CELSIUS using the PROMICE/WASA setup. Together with data obtained at lower energy they point to a dominance of the Roper excitation in this process. From the observed interference of its decay routes N* -> N sigma and N* -> Delta pi -> N sigma their energy-depe

Gerard Clement

We propose a new definition for the mass and angular momentum of neutral or electrically charged black holes in 2+1 gravity with two Killing vectors. These finite conserved quantities, associated with the SL(2,R) invariance of the reduced mechanical system, are shown to be identical to the quasilocal conserved quantities for an improved gravitational action

Rustam Sadykov

We prove that the homotopy class of a Morin mapping f: P^p --> Q^q with p-q odd contains a cusp mapping. This affirmatively solves a strengthened version of the Chess conjecture [DS Chess, A note on the classes [S_1^k(f)], Proc. Symp. Pure Math., 40 (1983) 221-224] and [VI Arnol'd, VA Vasil'ev, VV Goryunov, OV Lyashenko, Dynamical systems VI. Singula

Naoki Yoshida, Tom Abel, Lars Hernquist, Naoshi Sugiyama

(abridged) We use large cosmological simulations to study the origin of primordial star-forming clouds in a Lambda CDM universe, by following the formation of dark matter halos and the cooling of gas within them. To model the physics of chemically pristine gas, we employ a non-equilibrium treatment of the chemistry of 9 species and include cooling by molecul

Igor A. Bandos, Jose A. de Azcarraga, Jose M. Izquierdo, Jerzy Lukierski

We point out that the worldvolume coordinate functions $\hat{x}^μ(ξ)$ of a $p$-brane, treated as an independent object interacting with dynamical gravity, are Goldstone fields for spacetime diffeomorphisms gauge symmetry. The presence of this gauge invariance is exhibited by its associated Noether identity, which expresses that the source equations follow fr

J. Rogel-Salazar, G. H. C. New, S. Chavez-Cerda

In a simple picture, a Bessel beam is viewed as a transverse standing wave formed in the interference region between incoming and outgoing conical waves. Based on this interpretation we propose an optical resonator that supports modes that are approximations to Bessel-Gauss beams. The Fox-Li algorithm in two transverse dimension is applied to confirm the con

Samim Erhan, Peter E. Schlein

One of the key experimental issues in high energy hadron physics is the extent to which data from the diffractive interaction mechanism may be described by a factorized formula which is the product of a universal term describing the probability of finding a Pomeron in a proton (loosely referred to as the "Pomeron flux-factor") and a term decribing th

L. F. Alday, M. Cirafici

In this note we provide an explicit example of type IIB supersymmetric D3-branes solution on a pp-wave like background, consisting in the product of an eight-dimensional pp-wave times a two-dimensional flat space. An interesting property of our solution is the fully localization of the D3-branes (i.e. the solution depends on all the transverse coordinates).

Giancarlo Pace, Luca Pasquini, Sergio Ortolani

Wilson and Bappu (1957) have shown the existence of a remarkable correlation between the width of the emission in the core of the K line of Ca II and the absolute visual magnitude of late--type stars. Here we present a new calibration of the Wilson--Bappu effect based on a sample of 119 nearby stars. We use, for the first time, width measurements based on hi

Taksu Cheon

A self-similar hierarchical solution that is both dynamically and evolutionarily stable is found to the multi dimensional Lotka-Volterra equation with a single chain of prey-predator relations. This gives a simple and natural explanation to the key features of hierarchical ecosystems, such as its ubiquity, pyramidal population distribution, and higher aggres

Neven Bilic, Hrvoje Nikolic

We study the propagation of pions at finite temperature and finite chemical potential in the framework of the linear sigma model with 2 quark flavors and $N_c$ colors. The velocity of massless pions in general differs from that of light. One-loop calculations show that in the chiral symmetry broken phase pions, under certain conditions, propagate faster than

A. Fukunaga, K. -I. Izawa

QCD in a five-dimensional sliced AdS bulk with chiral extra-quarks on the boundaries is generically free from the strong CP problem. Accidental axial symmetry is naturally present except for suppressed breaking interactions, which plays a role of the Peccei-Quinn symmetry to make the strong CP phase sufficiently small. Breaking suppression and enhancement du

Minoru Soda, Yukio Yasui, Toshiaki Fujita, Takeshi Miyashita

Neutron diffraction studies have been carried out on a single crystal of oxygen-deficient perovskite TbBaCo2O5.5 in the temperature range of 7-370 K. There have been observed several magnetic or structural transitions. Among these, the existence of the transitions to the insulating phase from the metallic one at ~340 K, to the one with the ferromagnetic mome

P. J. Forrester, N. E. Frankel, T. M. Garoni

The density matrix for the impenetrable Bose gas in Dirichlet and Neumann boundary conditions can be written in terms of $<\prod_{l=1}^n| \cosϕ_1-\cosθ_l| |\cosϕ_2-\cosθ_l|>$, where the average is with respect to the eigenvalue probability density function for random unitary matrices from the classical groups $Sp(n)$ and $O^+(2n)$ respectively. In the large

Aephraim M. Steinberg

This chapter is based on a talk given at the Science and Ultimate Reality meeting in March, 2002, in honour of John Archibald Wheeler. In it, I discuss some questions related to what can and cannot be said about the history of a quantum mechanical system. Relying heavily on the weak- measurement formalism of Aharonov and coworkers, I argue that there is much

Gabrielle Magro

Basic ideas about noncommuting coordinates are summarized, and then coordinate noncommutativity, as it arises in the Landau problem, is investigated. I review a quantum solution to the Landau problem, and evaluate the coordinate commutator in a truncated state space of Landau levels. Restriction to the lowest Landau level reproduces the well known commutator

Viv Kendon, Ben Tregenna

We present an introduction to coined quantum walks on regular graphs, which have been developed in the past few years as an alternative to quantum Fourier transforms for underpinning algorithms for quantum computation. We then describe our results on the effects of decoherence on these quantum walks on a line, cycle and hypercube. We find high sensitivity to

N. Gisin, I. Marcikic, H. de Riedmatten, W. Tittel

Using 2 km of standard telecom optical fibres, we teleport qubits carried by photons of 1310 nm wavelength to qubits in another lab carried by a photons of 1550 nm wavelength. The photons to be teleported and the necessary entangled photon pairs are created in two different non-linear crystals. The measured mean fidelity is of 81.2 %. We discuss how this cou

I. Marcikic, H. de Riedmatten, W. Tittel, H. Zbinden

Elementary 2-dimensional quantum states (qubits) encoded in 1300 nm wavelength photons are teleported onto 1550 nm photons. The use of telecommunication wavelengths enables to take advantage of standard optical fibre and permits to teleport from one lab to a distant one, 55 m away, connected by 2 km of fibre. A teleportation fidelity of 81.2 % is reported. T

Halina V. Grushevskaya, Leonid I. Gurskii

A projection operator technique for solution of relativistic wave equation on non-compact group has been proposed. This technique was applied to the construction of wave equations for charged vector boson in a potential field. The equations were shown to approximately describe a hydrogen-like atom and allow estimating of relativistic corrections such as a fi

G. M. D&#39;Ariano, C. Macchiavello

We consider cloning transformations of equatorial qubits and qutrits, with the transformation covariant for rotation of the phases. The optimal cloning maps are derived without simplifying assumptions from first principles, for any number of input and output qubits, and for a single input qutrit and any number of output qutrits. We also compare the cloning m

H. Ardavan, A. Ardavan, J. Singleton

We present a theoretical study of the emission from a superluminal polarization current whose distribution pattern rotates (with an angular frequency $ω$) and oscillates (with a frequency $Ω$) at the same time, and which comprises both poloidal and toroidal components. This type of polarization current is found in recent practical machines designed to invest

S. V. Karpov, A. L. Bas&#39;ko, A. K. Popov, V. V. Slabko

Based on the theory of the optical properties of fractal clusters, which is an operator-based modification of the coupled-dipole method, an alternate solution is proposed for the problem of adequately describing the evolution of optical spectra of any polydisperse silver colloid with particles falling within the range of most characteristic sizes (5 - 30 nm)

Hiroshi Miyazaki, Masashi Hase, Hideki T. Miyazaki, Yoichi Kurokawa

We investigate numerically optical properties of novel two-dimensional photonic materials where parallel dielectric rods are randomly placed with the restriction that the distance between rods is larger than a certain value. A large complete photonic gap (PG) is found when rods have sufficient density and dielectric contrast. Our result shows that neither lo

S. Rudiger, D. G. Miguez, A. P. Munuzuri, F. Sagues

We study, both theoretically and experimentally, the dynamical response of Turing patterns to a spatio-temporal forcing in the form of a travelling wave modulation of a control parameter. We show that from strictly spatial resonance, it is possible to induce new, generic dynamical behaviors, including temporally-modulated travelling waves and localized trave

P. Kondratenko

Five-dimensional model of space-time (anti-de-Sitter space), described within the dodecahedron symmetry is offered in the article. According to the offered model graviton is the double five-dimensional vortex (soliton) that provides its stability and allows it to unite the Universe. The interaction between graviton and particles of the Universe stipulates th

R. P. Duperray, K. V. Protasov, L. Derome, M. Buenerd

A simple coalescence model based on the same diagrammatic approach of antimatter production in hadronic collisions as used previously for antideuterons is used here for the hadroproduction of mass 3 antinuclei. It is shown that the model is able to reproduce the existing experimental data on Tbar and 3hebar production without any additional parameter.

Tobias Frederico, J. H. O. Sales, B. V. Carlson, P. U. Sauer

We show the light-front representation of the field theoretical Bethe-Salpeter equation (BSE) in the ladder approximation using the quasi potential reduction. We discuss the equivalence of the covariant ladder Bethe-Salpeter equation with an infinite set of coupled equations for the Green&#39;s functions of the different light-front Fock-states.

A. A. Isayev

In the framework of a Fermi liquid theory it is considered the possibility of ferromagnetic and antiferromagnetic phase transitions in symmetric nuclear matter with Skyrme effective interaction. The zero temperature dependence of ferromagnetic and antiferromagnetic spin polarization parameters as functions of density is found for SkM$^*$, SGII effective forc

E. V. Ferapontov, M. V. Pavlov

We demonstrate that Plebański&#39;s first heavenly equation decouples in infinitely many ways into a triple of commuting (1+1)-dimensional systems of hydrodynamic type which satisfy the Egorov property. Solving these systems by the generalized hodograph method, one can construct exact solutions of the heavenly equation parametrized by arbitrary functions of

A. G. Ramm

Completeness of the set of products of the derivatives of the solutions to the equation $(av&#39;)&#39;-łv=0, v(0,ł)=0$ is proved. This property is used to prove the uniqueness of the solution to an inverse problem of finding conductivity in the heat equation $\dot{u}=(a(x)u&#39;)&#39;, u(x,0)=0, u(0,t)=0,\ u(1,t)=f(t)$ known for all $t>0$, from the heat flu

A. G. Ramm

Modified Rayleigh conjecture (MRC) in scattering theory is proposed and justified. MRC allows one to develop numerical algorithms for solving direct scattering problems related to acoustic wave scattering by soft and hard obstacles of arbitrary shapes. It gives an error estimate for solving the direct scattering problem. It suggests a numerical method for fi

David Sheppard

We show that every morphism from a degree 5 hypersurface in 4-dimensional projective space to a nonsingular degree 3 hypersurface in 4-dimensional projective space is necessarily constant. In the process, we also classify morphisms from the projective plane to nonsingular cubic threefolds given by degree 3 polynomials.

David Sheppard

We show that for every morphism f between nonsingular hypersurfaces of dimension at least 3 and of general type in projective space, there is an everywhere defined endomorphism F of projective space that restricts to f. As a corollary, we see that if X,Y are nonsingular hypersurfaces of general type of dimension at least 3 such that there is a nonconstant mo

Peter Schauenburg

We give a definition of a noncommutative torsor by a subset of the axioms previously given by Grunspan. We show that noncommutative torsors are an equivalent description of Hopf-Galois objects (without specifying the Hopf algebra). In particular, this shows that the endomorphism of a torsor featuring in Grunspan&#39;s definition is redundant.

A. G. Ramm, A. B. Smirnova, A. Favini

A nonlinear operator equation $F(x)=0$, $F:H\to H,$ in a Hilbert space is considered. Continuous Newton&#39;s-type procedures based on a construction of a dynamical system with the trajectory starting at some initial point $x_0$ and becoming asymptotically close to a solution of $F(x)=0$ as $t\to +\infty$ are discussed. Well-posed and ill-posed problems are

A. G. Ramm

Assume that $$ Au=f,\quad (1) $$ is a solvable linear equation in a Hilbert space, $||A||<\infty$, and $R(A)$ is not closed, so problem (1) is ill-posed. Here $R(A)$ is the range of the linear operator $A$. A DSM (dynamical systems method) for solving (1), consists of solving the following Cauchy problem: $$ \dot u= -u +(B+\ep(t))^{-1}A^*f, \quad u(0)=u_0, \

Franz Lemmermeyer

Let L/F be a dihedral extension of degree 2p, where p is an odd prime. Let K/F and k/F be subextensions of L/F with degrees p and 2, respectively. Then we will study relations between the p-ranks of the class groups Cl(K) and Cl(k).

I. Boikov, A. G. Ramm

Cubature formulas, asymptotically optimal with respect to accuracy, are derived for calculating multidimensional weakly singular integrals. They are used for developing a universal code for calculating capacitances of conductors of arbitrary shapes.

A. G. Ramm

This paper is a continuation of the paper (A.G.Ramm, Amer. Math. Monthly, 108, N 9, (2001), 855-860), where bounded Fredholm operators are studied. The theory of bounded linear Fredholm-type operators is presented in many texts. This paper is written for a broad audience and the author tries to give simple and short arguments.

A. G. Ramm

The Newton-Sabatier method for solving inverse scattering problem with fixed-energy phase shifts for a sperically symmetric potential is discussed. It is shown that this method is fundamentally wrong: in general it cannot be carried through, the basic ansatz of R.Newton is wrong: the transformation kernel does not have the form postulated in this ansatz, in

A. G. Ramm

Inequalities for the transformation operator kernel $A(x,y)$ in terms of $F$-function are given, and vice versa. These inequalities are applied to inverse scattering on half-line. Characterization of the scattering data corresponding to the usual scattering class $L_{1,1}$ of the potentials, to the class of compactly supported potentials, and to the class of

Alexander G. Ramm, A. Galstian

Several methods for solving efficiently the one-dimensional deconvolution problem are proposed. The problem is to solve the Volterra equation ${\mathbf k} u:=\int_0^t k(t-s)u(s)ds=g(t),\quad 0\leq t\leq T$. The data, $g(t)$, are noisy. Of special practical interest is the case when the data are noisy and known at a discrete set of times. A general approach t

A. G. Ramm

Let $F$ be a nonlinear Frechet differentiable map in a real Hilbert space. Condition sufficient for existence of a solution to the equation $F(u)=0$ is given, and a method (dynamical systems method, DSM) to calculate the solution as the limit of the solution to a Cauchy problem is justified under suitable assumptions.

A. G. Ramm

Several questions of approximation theory are discussed: 1) can one approximate stably in $L^\infty$ norm $f^\prime$ given approximation $f_δ, \parallel f_δ- f \parallel_{L^\infty} < δ$, of an unknown smooth function $f(x)$, such that $\parallel f^\prime (x) \parallel_{L^\infty} \leq m_1$? 2) can one approximate an arbitrary $f \in L^2(D), D \subset \R^n, n

A. G. Ramm

A new understanding of the notion of regularizer is proposed. It is argued that this new notion is more realistic than the old one and better fits the practical computational needs. An example of the regularizer in the new sense is given. A method for constructing regularizers in the new sense is proposed and justified.

A. G. Ramm

Consider an operator equation $F(u)=0$ in a real Hilbert space. The problem of solving this equation is ill-posed if the operator $F&#39;(u)$ is not boundedly invertible, and well-posed otherwise. A general method, dynamical systems method (DSM) for solving linear and nonlinear ill-posed problems in a Hilbert space is presented. This method consists of the c

A. G. Ramm

Let $(1) Rh=f$, $0\leq x\leq L$, $Rh=\int^L_0 R(x,y)h(y) dy$, where the kernel $R(x,y)$ satisfies the equation $QR=Pδ(x-y)$. Here $Q$ and $P$ are formal differential operators of order $n$ and $m<n$, respectively, $n$ and $m$ are nonnegative even integers, $n>0$, $m\geq 0$, $Qu:=q_n(x)u^{(n)} + \sum^{n-1}_{j=0} q_j(x) u^{(j)}$, $Ph:=h^{(m)} +\sum^{m-1}_{j=0}

Craig J. Sutton

We generalize Sunada&#39;s method to produce new examples of closed, locally non-isometric manifolds which are isospectral. In particular, we produce pairs of isospectral, simply-connected, locally non-isometric normal homogeneous spaces. These pairs also allow us to see that in general group actions with discrete spectra are not determined up to measurable

David Joyner, Pablo Lejarraga

Let $G$ be a connected semi-simple group defined over and algebraically closed field, $T$ a fixed Cartan, $B$ a fixed Borel containing $T$, $S$ a set of simple reflections associated to the simple positive roots corresponding to $(T,B)$, and let ${\cal B}\cong G/B$ denote the Borel variety. For any $s_i\in S$, $1\leq i\leq n$, let $\bar{O}(s_1,..., s_n)= \{(

Stefan Haller

Let $M$ be a closed symplectic manifold and suppose $M\to P\to B$ is a Hamiltonian fibration. Lalonde and McDuff raised the question whether one always has $H^*(P;\mathbb Q)=H^*(M;\mathbb Q)\otimes H^*(B;\mathbb Q)$ as vector spaces. This is known as the c--splitting conjecture. They showed, that this indeed holds whenever the base is a sphere. Using their t

Franck Leprevost, Michael E. Pohst, Andreas M. Schoepp

Soit l un entier et E_{c,l} la famille de Kubert des courbes elliptiques definies sur Q munies d&#39;un point rationnel A d&#39;ordre l. On note F_{c,l} la courbe elliptique quotient de E_{c,l} par le groupe engendre&#39; par A, et f_l l&#39;isogenie de E_{c,l} sur F_{c,l}. Pour l = 3, 4, 5 et 6, nous construisons explicitement, pour des parametrisations con

Paul-Andi Nagy, Constantin Vernicos

We study $n$ dimensional Riemanniann manifolds with harmonic forms of constant length and first Betti number equal to $n-1$ showing that they are 2-steps nilmanifolds with some special metrics. We also characterise, in terms of properties on the product of harmonic forms, the left invariant metrics among them. This allows us to clarify the case of equality i

Beata Randrianantoanina

We study two questions posed by Johnson, Lindenstrauss, Preiss, and Schechtman, concerning the structure of level sets of uniform and Lipschitz quotient maps from $R^n\to R$. We show that if $f:R^n\to R$, $n\geq 2$, is a uniform quotient map then for every $t\in R$, $f^{-1}(t)$ has a bounded number of components, each component of $f^{-1}(t)$ separates $R^n$

Benoit Fresse

We consider partitions of a set with $r$ elements ordered by refinement. We consider the simplicial complex $\bar{K}(r)$ formed by chains of partitions which starts at the smallest element and ends at the largest element of the partition poset. A classical theorem asserts that $\bar{K}(r)$ is equivalent to a wedge of $r-1$-dimensional spheres. In addition, t

Zakaria Giunashvili

We extend the problem of finding Hamiltonian-invariant volume forms on a Poisson manifold to the problem of construction of Hamiltonian-invariant generalized functions. For this we introduce the notion of generalized center of a Poisson algebra, which is the space of generalized Casimir functions. We study as the case when the set of test-objects for general

Alex D. Gottlieb

The jackknife variance estimator and the the infinitesimal jackknife variance estimator are shown to be asymptotically equivalent if the functional of interest is a smooth function of the mean or a trimmed L-statistic with Hoelder continuous weight function.

Song Wang

In this note we study the symmetric powers of strongly modular icosahedral representations $ρ$ of ${\rm Gal} (\bar{F}/F)$, $F$ a number field, and their twisted $L$--functions. We prove that for such $ρ$, there exists a cuspidal automorphic representation $Π= Π_{\infty} \otimes Π_{f}$ of $GL_{6} (\mathbb{A}_{F})$ such that $L (s, {\rm sym}^{5} (ρ)) = L (s, Π

Roland Bacher, Robin Chapman

We study characteristic polynomials of symmetric matrices with entries ${i+j\choose i}$ the binomial coefficients, over finite fields.

A. V. Jayanthan, Balwant Singh, J. K. Verma

We present short and elementary proofs of two theorems of Huckaba and Marley, while generalizing them at the same time to the case of a module. The theorems concern a characterization of the depth of the associated graded ring of a Cohen-Macaulay module, with respect to a Hilbert filtration, in terms of the Hilbert coefficient e_1. As an application, we deri

Andrei Okounkov, Nikolai Reshetikhin

Schur process is a time-dependent analog of the Schur measure on partitions studied in math.RT/9907127. Our first result is that the correlation functions of the Schur process are determinants with a kernel that has a nice contour integral representation in terms of the parameters of the process. This general result is then applied to a particular specializa

Olivera Miskovic, Jorge Zanelli

Hamiltonian systems with linearly dependent constraints (irregular systems), are classified according to their behavior in the vicinity of the constraint surface. For these systems, the standard Dirac procedure is not directly applicable. However, Dirac&#39;s treatment can be slightly modified to obtain, in some cases, a Hamiltonian description completely eq

Nora Breton

In this work we probe the Born-Infeld (BI) black hole in the isolated horizon framework. It turns out that the BI black hole is consistent with the heuristic model for colored black holes proposed by Ashtekar et al [(2001) Class.Quant.Grav. v. 18, 919-940]. The model points to the unstability of the BI black hole.

J. D. Laenge, M. Engelhardt, H. Reinhardt

The one-loop energy density of an infinitely thin static magnetic vortex in SU(2) Yang-Mills theory is evaluated using the Schroedinger picture. Both the gluonic fluctuations as well as the quarks in the vortex background are included. The energy density of the magnetic vortex is discussed as a function of the magnetic flux. The center vortices correspond to

V. I. Shevchenko

The structure of leading nonperturbative corrections to the static Coulomb potential in QCD at small distances is analyzed. We argue in favor of the correction linearly dependent on distance and remark that lattice measurements of static potential for charges in higher representations can distinguish between different phenomenological models used to describe

Richard F. Lebed

The 1/N_c expansion (N_c being the number of QCD colors) has been applied in recent papers to the phenomenology of excited baryon resonances. This talk surveys the work done to date, and discusses its successes and remaining challenges.

Biswarup Mukhopadhyaya

The existence of neutrino mass and mixing is a strong pointer towards physics beyond the standard model. An overview of the possibility of having neutrino masses in supersymmetric theories is attempted here. Some of the recent works reviewed suggest Dirac masses, whereas others include Majorana masses as well. Side by side, it is shown how R-parity violating

C. Giunti, M. Laveder

A Neutrino Unbound gem (http://www.to.infn.it/~giunti/NU). Essential information (formulas, figures, tables, references, etc.) on solar neutrinos.

B. Machet

Systems of neutral interacting mesons are investigated, concerning in particular the validity of their description by an effective hamiltonian. First, I study its connection to quantum field theory and show that the spectrum of such systems cannot be reduced in general to the one of a single constant effective mass matrix. Choosing nevertheless to work in th

M. Beccaria, F. M. Renard, C. Verzegnassi

We consider the production, at future lepton colliders, of final fermion, sfermion, scalar pairs in SUSY models. For third family fermions and sfermions and for charged Higgses, the leading Yukawa effect at one loop for large c.m. energies comes from a linear logarithm of Sudakov type, that only depends, in the MSSM, on one SUSY mass scale and on tan(beta).

M. Beccaria, F. M. Renard, C. Verzegnassi

We consider the high energy behaviour of the amplitudes for production of leptons, quarks, Higgs bosons, sleptons, squarks, gauge bosons, charginos, neutralinos. We concentrate our discussion on the universal (process independent) logarithmic terms which factorize the Born amplitude and which are typically of the form [a ln(s/m^2)-ln^2(s/m^2)]. We perform a

S. Pislak, R. Appel, G. S. Atoyan, B. Bassalleck

We report experimental details and results of a new measurement of the decay K+ -> pi+pi-e+nue (Ke4}. A sample of more than 400,000 Ke4 events with low background has been collected by Experiment 865 at the Brookhaven Alternate Gradient Synchrotron. From these data, the branching ratio (4.11+-0.01+-0.11)*10**(-5) and the pi-pi invariant mass dependence of th

B. Ahmed, G. J. Alner, H. Araujo, J. C. Barton

The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg x year exposure) have been used to set upper limits on

V. A. Kudryavtsev, P. K. Lightfoot, J. E. McMillan, M. Robinson

The neutron background at the underground laboratory at Boulby - a site for several dark matter experiments - is discussed. Special emphasis is put on the neutron background produced by cosmic-ray muons. The most recent versions of the muon propagation code MUSIC, and particle transport code FLUKA are used to evaluate muon and neutron fluxes. The results of

Romesh K. Kaul, S. Kalyana Rama

Recent suggestion, that the emission of a quantum of energy corresponding to the asymptotic value of quasinormal modes of a Schwarzschild black hole should be associated with the loss of spin one punctures from the black hole horizon, fixes the Immirzi parameter to a definite value. We show that saturating the horizon with spin one punctures reproduces the e

Florian Siebel, Jose A. Font, Ewald Mueller, Philippos Papadopoulos

We present results from axisymmetric stellar core collapse simulations in general relativity. Our hydrodynamics code has proved robust and accurate enough to allow for a detailed analysis of the global dynamics of the collapse. Contrary to traditional approaches based on the 3+1 formulation of the gravitational field equations, our framework uses a foliation

Sugumi Kanno, Misao Sasaki, Jiro Soda

We propose a cosmological braneworld scenario in which two branes collide and emerge as reborn branes with signs of tensions opposite to the original tensions of respective branes. In this scenario, the branes are assumed to be inflating. However, the whole dynamics is different from the usual inflation due to the non-trivial dynamics of the radion field. Tr

Jiro Soda, Sugumi Kanno

We develop the general formalism to study the low energy regime of the brane world. We apply our formalism to the single brane model where the AdS/CFT correspondence will take an important role. We also consider the two-brane system and show the system is described by the quasi-scalar tensor gravity. Our result provides a basis for predicting CMB fluctuation

A. N. Makarenko, V. V. Obukhov, K. E. Osetrin

We consider brane Kantowski-Sachs Universe when bulk space is five-dimensional Anti-deSitter space. The corresponding cosmological equations with perfect fluid are written. For several specific choices of relation between energy and pressure it is found the behavior of scale factors at early time. In particulary, for $γ=3/2$ Kantowski-Sachs brane cosmology i

Jeongwon Ho, F. C. Khanna, Chul H. Lee

The Klein-Gordon-Einstein equations of classical real scalar fields have time-dependent solutions (periodic in time). We show that quantum real scalar fields can form non-oscillating (static) solitonic objects, which are quite similar to the solutions describing boson stars formed with classical and quantum complex scalar fields (the latter will be studied i

Alex Brodsky, Jan B. Pedersen, Alan Wagner

Message passing programs commonly use buffers to avoid unnecessary synchronizations and to improve performance by overlapping communication with computation. Unfortunately, using buffers makes the program no longer portable, potentially unable to complete on systems without a sufficient number of buffers. Effective buffer use entails that the minimum number

M. Sampoli, P. Benassi, R. Eramo, L. Angelani

The potential energy landscape in the Kob-Andersen Lennard-Jones binary mixture model has been studied carefully from liquid down to the supercooled regime, from T =2 down to T =0.46. One thousand of independent configurations along the time evolution have been examined at each investigated temperature. From the starting configuration we searched the nearest

Changyu Hu, Xiang Li, Jie Liang

Potential functions are critical for computational studies of protein structure prediction, folding, and sequence design. A class of widely used potentials for coarse grained models of proteins are contact potentials in the form of weighted linear sum of pairwise contacts. However, these potentials have been shown to be unsuitable choices because they cannot

W. A. Atkinson, P. J. Hirschfeld, Lingyin Zhu

We study the local density of states around potential scatterers in d-wave superconductors, and show that quantum interference between impurity states is not negligible for experimentally relevant impurity concentrations. The two impurity model is used as a paradigm to understand these effects analytically and in interpreting numerical solutions of the Bogol

A. K. Rajagopal

The concepts of quantity of heat and work are deduced in the non-extensive statistical mechanics context, following steps in parallel to those employed in the extensive statistical mechanics.

Carlos Lobo, Alice Sinatra, Yvan Castin

We show that the formation of a vortex lattice in a weakly interacting Bose condensed gas can be modeled with the nonlinear Schrodinger equation for both T=0 and finite temperatures without the need for an explicit damping term. Applying a weak rotating anisotropic harmonic potential we find numerically that the turbulent dynamics of the field produces an ef

R. J. C. Bosman, W. A. van Leeuwen, B. Wemmenhove

A toy model of a neural network in which both Hebbian learning and reinforcement learning occur is studied. The problem of `path interference&#39;, which makes that the neural net quickly forgets previously learned input-output relations is tackled by adding a Hebbian term (proportional to the learning rate $η$) to the reinforcement term (proportional to $ρ$

M. Yu. Kagan, A. V. Klaptsov, I. V. Brodsky, K. I. Kugel

We study the possibility of nanoscale phase separation in manganites in the framework of the double exchange model. The homogeneous canted state of this model is proved to be unstable toward the formation of small ferromagnetic droplets inside an antiferromagnetic insulating matrix. For the ferromagnetic polaronic state we analyze the quantum effects related

D. Mentrup, J. Schnack

While thermostated time evolutions stand on firm grounds and are widely used in classical molecular dynamics (MD) simulations, similar methods for quantum MD schemes are still lacking. In the special case of a quantum particle in a harmonic potential, it has been shown that the framework of coherent states permits to set up equations of motion for an isother

Peter Olsson

The anisotropic frustrated three dimensional (3D) XY model with disorder in the coupling constants is simulated as a model of a point disordered superconductor in an applied magnetic field. From a finite size scaling analysis of the helicity modulus it is concluded that the data is consistent with a finite temperature transition with isotropic scaling and th

Bhargavi Srinivasan, Giuliano Benenti, Dima L. Shepelyansky

We study numerically the ground-state properties of the repulsive Hubbard model for spin-1/2 electrons on two-dimensional lattices with disordered on-site energies. The projector quantum Monte Carlo method is used to obtain very accurate values of the ground-state charge density distributions with $N_p$ and $N_p+1$ particles. The difference in these charge d

Armel Le Bail, Lachlan Cranswick

Four years after the first structure determination by powder diffractometry (SDPD) round robin, a second one shows that SDPD is still not routine.