April 2001 arXiv papers — page 2

Saul Barshay, Georg Kreyerhoff

A simple power-law growth of charged-particle multiplicities near midrapidity in central Au+Au collisions at $\sqrt{s_{NN}}=56$ and 130 GeV, recently measured at RHIC, is derived. We give predictions for the central particle densities up to $\sqrt{s_{NN}}=1800$ GeV. A strong growth of the Au+Au densities above those for $\ol{p}(p)-p$ collisions is predicted.

N. Ya. Ivanov

We present the threshold resummation for the single spin asymmetry in heavy flavor production by linearly polarized photons. We analyze the soft-gluon contributions to the asymmetry at fixed order in $α_s$ to the next-to-leading logarithmic accuracy. Our analysis shows that, contrary to the production cross section, the azimuthal asymmetry is practically ins

Jayajit Das, Madan Rao, Sriram Ramaswamy

We drive a $d$-dimensional Heisenberg magnet using an anisotropic current. The continuum Langevin equation is analysed using a dynamical renormalization group and numerical simulations. We discover a rich steady-state phase diagram, including a critical point in a new nonequilibrium universality class, and a spatiotemporally chaotic phase. The latter may be

Xenia de la Ossa, Bogdan Florea, Harald Skarke

We study D-branes on smooth noncompact toric Calabi-Yau manifolds that are resolutions of abelian orbifold singularities. Such a space has a distinguished basis {S_i} for the compactly supported K-theory. Using local mirror symmetry we demonstrate that the S_i have simple transformation properties under monodromy; in particular, they are the objects that gen

A. Mironov

We formulate the problem of finding self-dual Hamiltonians (associated with integrable systems) as deformations of free systems given on various symplectic manifolds and discuss several known explicit examples, including recently found double elliptic Hamiltonians. We consider as basic the notion of self-duality, while the duality in integrable systems (of t

Cristopher Moore, Alexander Russell

Recently, it has been shown that one-dimensional quantum walks can mix more quickly than classical random walks, suggesting that quantum Monte Carlo algorithms can outperform their classical counterparts. We study two quantum walks on the n-dimensional hypercube, one in discrete time and one in continuous time. In both cases we show that the quantum walk mix

Laszlo E. Szabo

The paper is withdrawn by the author, due to the fact that in Larsson's Phys.Lett. A256 (1999) 245-252 (quant-ph/9901074) a similar model was published with even higher efficiency.

Behram N. Kursunoglu

This paper contains results obtained as solutions of the Unified Field Theory equations. It yields space nonlinear oscillations, a quartet of gravitational forces, quintessence, and replaces Einstein's Cosmological Constant by an invariant parameter $r_0$ which prevails over the entire evolution of the Universe.

O. Juillet, Ph. Chomaz, D. Lacroix, F. Gulminelli

We investigate a reformulation of the dynamics of interacting fermion systems in terms of a stochastic extension of Time Dependent Hartree-Fock equations. The noise is found from a path-integral representation of the evolution operator and allows to interpret the exact N-body state as a coherent average over Slater determinants evolving under the random mean

Mario J. Edmundo

We develop in this paper the theory of covers for Hausdorff properly $\bigvee $-definable manifolds with definable choice in an o-minimal structure $\N$. In particular, we show that given an $\N$-definably connected $\N$-definable group $G$ we have $1\to π_1(G)\to \tilde{G}\stackrel{p}\to G\to 1$ in the category of strictly properly $\bigvee $-definable grou

Carla Dionisi, Giorgio Ottaviani

Let $A$, $B$ be multidimensional matrices of boundary format respectively $\prod_{i=0}^p(k_i+1)$, $\prod_{j=0}^q(l_j+1)$. Assume that $k_p=l_0$ so that the convolution $A\ast B$ is defined. We prove that $Det (A\ast B)=Det(A)^α\cdot Det(B)^β$ where $α= \frac {l_0!}{l_1!... l_q!}$, $β=\frac {(k_0+1)!}{k_1! ... k_{p-1}!(k_p+1)!}$ and $Det$ is the hyperdetermin

A. I. Iliev, Kh. I. Semerdzhiev

Iterative methods for the simultaneous determination of all roots of an equation are dis-cussed. The multiplicities of the roots are assumed to be known in advance. The methods are proved to have a cubical rate of convergence. Numerical examples are given.

J. Manjavidze

Paper contains description of the fields nonlinear modes successive quantization scheme. It is shown that the path integrals for absorption part of amplitudes are defined on the Dirac ($\d$-like) functional measure. This permits arbitrary transformation of the functional integral variables. New form of the perturbation theory achieved by mapping the quantum

Z. Chang, C. B. Guan, H. Y. Guo

AdS dynamics for massive scalar field is studied both by solving exactly the equation of motion and by constructing bulk-boundary propagator. A Robertson-Walker-like metric is deduced from the familiar SO(2,n) invariant metric. The metric allows us to present a time-like Killing vector, which is not only invariant under space-like transformations but also in

A. Dymarsky

We present a first-quantized formulation of the quadratic non-commutative field theory in the background of abelian (gauge) field. Even in this simple case the Hamiltonian of a propagating particle depends non-trivially on the momentum (since external fields depend on location of the Landau orbit) so that one can not integrate out momentum to obtain a local

Chris Austin

A brief summary is given of the Group-Variation Equations and the island diagram confinement mechanism, with an explanation of the prediction that the cylinder-topology minimal-area spanning surface term in the correlation function of two Wilson loops at large $N_c$, when it exists, must have a pre-exponential factor, which for large area $A$ of the minimal-

Pierre Fayet

We recall the obstacles which seemed, long ago, to prevent supersymmetry from possibly being a fundamental symmetry of Nature. Which bosons and fermions could be related? Is spontaneous supersymmetry breaking possible? Where is the spin-1/2 Goldstone fermion of supersymmetry? Can one define conserved baryon and lepton numbers in such theories, although they

Don Colladay, Alan Kostelecky

The derivation of cross sections and decay rates in the Lorentz-violating standard-model extension is discussed. General features of the physics are described, and some conceptual and calculational issues are addressed. As an illustrative example, the cross section for the specific process of electron-positron pair annihilation into two photons is obtained.

Yu. P. Goncharov

The black hole physics techniques and results are applied to find the set of the exact solutions of the SU(3)-Yang-Mills equations in Minkowski spacetime in the Lorentz gauge. All the solutions contain only the Coulomb-like or linear in $r$ components of SU(3)-connection. This allows one to obtain some possible exact and approximate solutions of the correspo

J. Manjavidze, A. Sissakian

The perturbation theory over inverse interaction constant $1/g$ is constructed for Yang-Mills theory. It is shown that the new perturbation theory is free from the gauge ghosts and Gribov's ambiguities, each order over $1/g$ presents the gauge-invariant quantity. It is remarkable that offered perturbation theory did not contain divergences, at least in t

J. Manjavidze, A. Sissakian

The perturbation theory around the soliton fields of the sin-Gordon model is developed in the coset space. It is shown by explicit calculations that all corrections to the topological soliton contribution are canceled exactly.

Lee Smolin

Barbour, Hawking, Misner and others have argued that time cannot play an essential role in the formulation of a quantum theory of cosmology. Here we present three challenges to their arguments, taken from works and remarks by Kauffman, Markopoulou and Newman. These can be seen to be based on two principles: that every observable in a theory of cosmology shou

M. I. Tsindlekht, I. Felner

We report the experimental study of linear and nonlinear ac properties of two types of samples of MgB2 prepared by different technologies. A commercial sample (Alfa Aesar) demonstrates two stages of a broad phase transition, whereas home-made metallic sample have one sharp transition. The temperature dependence of the rectified signal shows two peaks for the

K. Motohara, T. Yamada, F. Iwamuro, T. Maihara

We present low-resolution, near-IR JHK spectra of the weak z=2.39 radio galaxy 53W002 and its companion objects #18 and #19, obtained with OHS/CISCO on the Subaru Telescope. They cover rest-frame wavelengths of 3400-7200A, and many rest-optical emission lines are detected. Contributions to the broad-band flux from these emission lines are found to be very la

R. N. Ogley, S. J. Bell Burnell, R. E. Spencer, S. J. Newell

We have observed a number of minor radio flares in Cyg X-3 using the MERLIN array. Photometric observations show the system to be highly active with multiple flares on hourly timescales over the one month observing programme. Analysis of the source's power spectrum show no persistent periodicities in these data, and no evidence of the 4.8 hr orbital peri

J. J. M. in 't Zand, R. H. D. Corbet, F. E. Marshall

Dedicated monitoring of the transient X-ray pulsar XTE J1543-568 during the first year after its discovery has revealed the unambiguous detection of a binary orbit. The orbital period is 75.56+/-0.25 d, and the projected semi-major axis 353+/-8 lt-sec. The mass function and position in the pulse period versus orbital period diagram are consistent with XTE J1

K. -H. Chae, S. Mao, P. Augusto

We test possible lensing scenarios of the JVAS system B2114+022, in which two galaxies at different redshifts (``G1'' at $z_1 = 0.3157$ and ``G2'' at $z_2 = 0.5883$) are found within 2 arcseconds of quadruple radio sources. For our investigation, we use possible lensing constraints derived from a wealth of data on the radio sources obtained w

Sara L. Ellison, Sean G. Ryan, Jason X. Prochaska

The study of elemental abundances in Damped Lyman Alpha systems (DLAs) at high redshift represents one of our best opportunities to probe galaxy formation and chemical evolution at early times. By coupling measurements made in high z DLAs with our knowledge of abundances determined locally and with nucleosynthetic models, we can start to piece together the s

R. P. Olling, M. R. Merrifield

(Abridged) Axisymmetric models of the Milky Way exhibit strong interrelations between the Galactic constants (R_0 and T_0), the stellar columndensity (S_*) and the shape of the dark matter (DM) halo. Here we present analytical relations that can be used to investigate the effects of the uncertain gaseous velocity dispersion on the HI flaring constraints. The

Tolga Birkandan, M. Hortacsu

We study a scalar field in curved space in three dimensions. We obtain a static perturbative solution and show that this solution satisfies the exact equations in the asymptotic region at infinity. The new solution gives rise to a singularity in the curvature scalar at the origin. Our solution, however, necessitates the excising the region near the origin, t

Karl-Georg Schlesinger

We introduce a noncommutative and noncocommutative Hopf algebra which takes for certain Hopf categories (and therefore braided monoidal bicategories) a similar role as the Grothendieck- Teichmueller group for quasitensor categories. We also give a result which highly restricts the possibility for similar structures for even higher weak n-categories than bica

K. Sasaki

It is pointed out that the chiral anomaly in 1+1 dimensions should be observed in toroidal carbon nanotubes on a planar geometry with varying magnetic field. We show that the chiral anomaly is closely connected with the persistent current in a one-dimensional metallic ring.

S. Y. Li, R. Fan, X. H. Chen, C. H. Wang

The normal state resistivtity, upper critical field $H_{c2}$ and Hall coefficient $R_H$ in superconducting perovskite $MgCNi_3$ ($T_c \approx 8 K$) have been studied. Above 70 K, $ρ(T)$ fits well curve predicted by Bloch-Grüneisen theory consistently with electron-phonon scattering. $H_{c2}(0)$ was estimated to be about 15.0 Tesla within the weak-coupling BC

James P. Sethna, Valerie R. Coffman, Eugene Demler

We develop a simple computational model for cell boundary evolution in plastic deformation. We study the cell boundary size distribution and cell boundary misorientation distribution that experimentally have been found to have scaling forms that are largely material independent. The cell division acts as a source term in the misorientation distribution which

N. Graham, R. L. Jaffe, M. Quandt, H. Weigel

We study scattering theory identities previously obtained as consistency conditions in the context of one-loop quantum field theory calculations. We prove the identities using Jost function techniques and study applications.

Sumiyoshi Abe

Through the generalization of Khinchin's classical axiomatic foundation, a basis is developed for nonadditive information theory. The classical nonadditive conditional entropy indexed by the positive parameter q is introduced and then translated into quantum information. This quantity is nonnegative for classically correlated states but can take negative

L. Accardi, S. V. Kozyrev

In the present paper we outline the stochastic limit approach to superfluidity. The Hamiltonian describing the interaction between the Bose condensate and the normal phase is introduced. Sufficient in the stochastic limit condition of superfluidity is proposed. Existence of superfluidity in the stochastic limit of this system is proved and the non-linear (qu

B. Saghai, Z. Li

An extensive and systematic study of the recent eta photoproduction data up to 1.2 GeV is presented within a chiral constituent quark model. A model embodying all known nucleonic resonances shows clear need for a yet undiscovered third S11 resonance in the second resonance region, for which we determine the mass (1.729 GeV) and the total width (183 MeV). Fur

Wen-Xiu Ma

Binary Bargmann symmetry constraints are applied to decompose soliton equations into finite-dimensional Liouville integrable Hamiltonian systems, generated from so-called constrained flows. The resulting constraints on the potentials of soliton equations give rise to involutive solutions to soliton equations, and thus the integrability by quadratures are sho

Saharon Shelah, Akito Tsuboi

We consider implicit definability of the standard part {0,1,...} in nonstandard models of Peano arithmetic (PA), and we ask whether there is a model of PA in which the standard part is implicitly definable. In section 1, we define a certain class of formulas, and show that in any model of PA the standard part is not implicitly defined by using such formulas.

Heike Mildenberger, Saharon Shelah

Following Blass, we call a real a ``needed'' for a binary relation R on the reals if in every R-adequate set we find an element from which a is Turing computable. We show that every real needed for Cof(N) is hyperarithmetic. Replacing ``R-adequate'' by ``R-adequate with minimal cardinality'' we get related notion of being ``weakly nee

Martin A. Guest

This is an introduction to some of the analytic (or integrable systems) aspects of quantum cohomology which have attracted much attention during the last few years. The small quantum cohomology algebra, regarded as an example of a Frobenius manifold, is described in the original naive manner, without going into the technicalities of a rigorous definition. Th

Nikolaj Glazunov

Problems of (i) precise (exact) bound for families of hyperelliptic curves over prime finite fields and (ii) equidistribution of angles of Kloosterman sums are discussed.

A. Pashnev

The method of nonlinear realizations is applied for the conformally invariant description of the spinning particles in terms of geometrical quantities of the parameter spaces of the one dimensional N - extended superconformal groups. We develop the superspace approach to the cases of spin 0, 1/2, 1 particles and describe the alternative component approach in

O. V. Selyugin

Several methods of extracting the magnitude of the real parts of the elastic hadron scattering amplitude - from the experimental data are presented. These methods allows us to obtain the real parts at one definite point of the transfer momentum and with a high accuracy without knowledge of the precise values of the normalization coefficient and with minimum

K. Abe

Cabibbo-suppressed decays $B \to D^{(*)} K^-$ using a 10.4 fb$^{-1}$ data sample accumulated at the $Υ(4S)$ resonance with the Belle detector at the KEKB $e^+ e^-$ storage ring. The high-momentum particle identification system of Belle is used to isolate signals for $B\to D^0 K^-$, $D^+K^-$, $D^{*0}K^-$ and $D^{*+}K^-$ from the $B\to D^{(*)}π^-$ decay proces

Ning Wu

R measurement results in 2--5 GeV region by BESII is reported in this talk. The study on $σ$ particle in $J/ψ\to ωπ^+ π^-$, based on $7.8 \times 10^6$ BESI $J/ψ$ data, is also reported.

Valery S. Dryuma

Some properties of the 4-dim Riemannian spaces with metrics $$ ds^2=2(za_3-ta_4)dx^2+4(za_2-ta_3)dxdy+2(za_1-ta_2)dy^2+2dxdz+2dydt $$ associated with the second order nonlinear differential equations $$ y''+a_{1}(x,y){y'}^3+3a_{2}(x,y){y'}^2+3a_{3}(x,y)y'+a_{4}(x,y)=0 $$ with arbitrary coefficients $a_{i}(x,y)$ and 3-dim Einstein-Weyl spa

V. B. Bezerra, J. Spinelly, C. Romero

We study some aspects of three-dimensional gravity by extending Jackiw's scalar theory to (2+1)-dimensions and find a black hole solution. We show that in in general this teory does not possess a Newtonian limit except for special metric configurations.

G. Salis, D. D. Awschalom, Y. Ohno, H. Ohno

Time-resolved optical measurements of electron-spin dynamics in a (110) GaAs quantum well are used to study the consequences of a strongly anisotropic electron g-tensor, and the origin of previously discovered all-optical nuclear magnetic resonance. All components of the g-tensor are measured, and a strong anisotropy even along the in-plane directions is fou

Prabhakar P. Singh

We present the results of fully-relaxed, full-potential electronic structure calculations for the new superconductor MgB2, and BeB2, NaB2, and AlB2, using density-functional-based methods. Our results described in terms of (i) density of states (DOS), (ii) band-structure, and (iii) the DOS and the charge density around the Fermi energy EF, clearly show the i

S. Patnaik, L. D. Cooley, A. Gurevich, A. A. Polyanskii

An important predicted, but so far uncharacterized, property of the new superconductor MgB2 is electronic anisotropy arising from its layered crystal structure. Here we report on three c-axis oriented thin films, showing that the upper critical field anisotropy ratio Hc2par/Hc2perp is 1.8 to 2.0, the ratio increasing with higher resistivity. Measurements of

M. Dube, M. Rost, K. R. Elder, M. Alava

We argue that a proposed exponent identity [Phys. Rev. Lett 85, 1238 (2000)] for interface roughening in spontaneous imbibition is wrong. It rests on the assumption that the fluctuations are controlled by a single time scale, but liquid conservation imposes two distinct time scales.

A. V. Tsvyashchenko, L. N. Fomicheva, M. V. Magnitskaya, E. N. Shirani

We report the high-pressure synthesis of novel superconductor MgB$_2$ and some related compounds. The superconducting transition temperature of our samples of MgB$_2$ is equal to 36.6 K. The MgB$_2$ lattice parameters determined via X-ray diffraction are in excellent agreement with results of our ab initio calculations. The time-differential perturbed angula

Noriko Akutsu, Yasuhiro Akutsu, Takao Yamamoto

We study the vicinal surface of the restricted solid-on-solid model coupled with the Langmuir adsorbates which we regard as two-dimensional lattice gas without lateral interaction. The effect of the vapor pressure of the adsorbates in the environmental phase is taken into consideration through the chemical potential. We calculate the surface free energy $f$,

D. E. Feldman, Yuval Gefen

It is well known that while forward scattering has no effect on the conductance of one-dimensional systems, backscattering off a static impurity suppresses the current. We study the effect of a time-dependent point impurity on the conductance of a one-channel quantum wire. At strong repulsive interaction (Luttinger liquid parameter g<1/2), backscattering ren

F. Simon, A. Janossy, T. Feher, F. Muranyi

We have observed the conduction electron spin resonance (CESR) in fine powders of MgB2 both in the superconducting and normal states. The Pauli susceptibility is chi_s=2.0*10^{-5} emu/mole in the temperature range of 450 to 600 K. The spin relaxation rate has an anomalous temperature dependence. The CESR measured below T_c at several frequencies suggests tha

S. F. Wang, S. Y. Dai, Y. L. Zhou, Z. H. Chen

Superconducting MgB2 thin films were fabricated on Al2O3(0001) substrates under an ex-situ processing conditions. Boron thin films were deposited by pulsed laser deposition followed by a post-annealing process. Resistance measurements of the deposited MgB2 films show Tc of about 39K, while scanning electron microscopy and x-ray diffraction analysis indicate

Naoyuki Tamura, Hiroyuki Hirashita, Tsutomu T. Takeuchi

The virial mass ($M_{\rm vir}$)-metallicity relation among the Local Group dwarf spheroidal galaxies (dSphs) is examined. Hirashita, Takeuchi, & Tamura showed that the dSphs can be divided into two distinct classes with respect to the relation between their virial masses and luminosities: low-mass ($M_{\rm vir} \la 10^8 M_\odot$) and high-mass ($M_{\rm vir}

Izumi Hachisu, Mariko Kato

Recurrent nova CI Aquilae is still bright 300 days after the optical maximum, showing the slowest evolution among recurrent novae. We predict the turn-off time of CI Aql 2000 outburst coming in August 2001 after a supersoft X-ray source (SSS) phase lasts 250 days. We also predict helium enrichment of ejecta, He/H = 0.25 by number. Observational confirmations

A. K. Mittal, Daksh Lohiya

It is shown that Homogeneous radiation can not be included in the Fractal Cosmological model obtained earlier by assuming an isotropic fractal cosmography, General Relativity and the Copernican Principle.

A. R. Lima, M. Argollo de Menezes

In this letter we propose the use of physics techniques for entropy determination on constrained parameter optimization problems. The main feature of such techniques, the construction of an unbiased walk on energy space, suggests their use on the quest for optimal solutions of an optimization problem. Moreover, the entropy, and its associated density of stat

S. Dimopoulos, S. Kachru, N. Kaloper, A. Lawrence

Generic classes of string compactifications include ``brane throats&#39;&#39; emanating from the compact dimensions and separated by effective potential barriers raised by the background gravitational fields. The interaction of observers inside different throats occurs via tunnelling and is consequently weak. This provides a new mechanism for generating smal

Stephan J. Huber, Qaisar Shafi

We discuss Dirac neutrino masses and mixings in a scenario where both the standard model fermions and right handed neutrinos are bulk fields in a non-factorizable geometry in five dimensions. We show how the atmospheric and solar neutrino anomalies can be satisfactorily resolved, and in particular how bimaximal mixing is realized. We also consider rare proce

L. Arturo Urena-Lopez

In this paper, we study some interesting properties of a spherically symmetric oscillating soliton star made of a real time-dependent scalar field which is called an oscillaton. The known final configuration of an oscillaton consists of a stationary stage in which the scalar field and the metric coefficients oscillate in time if the scalar potential is quadr

Duncan S. Callaway, John E. Hopcroft, Jon M. Kleinberg, M. E. J. Newman

We analyze a minimal model of a growing network. At each time step, a new vertex is added; then, with probability delta, two vertices are chosen uniformly at random and joined by an undirected edge. This process is repeated for t time steps. In the limit of large t, the resulting graph displays surprisingly rich characteristics. In particular, a giant compon

Frantisek Slanina

The mean-field variant of the model of limit order driven market introduced recently by Maslov is formulated and solved. The agents do not have any strategies and the memory of the system is kept within the order book. We show that he evolution of the order book is governed by a matrix multiplicative process. The resulting stationary distribution of step-to-

A. Aguilar, L. B. Auerbach, R. L. Burman, D. O. Caldwell

A search for muon anti-neutrino to electron anti-neutrino oscillations was conducted by the Liquid Scintillator Neutrino Detector at the Los Alamos Neutron Science Center using muon anti-neutrinos from positive muon decay at rest. A total excess of 87.9 +/- 22.4 +/- 6.0 events consistent with electron anti-neutrino plus proton scattering to positron plus neu

F. Chevy, K. W. Madison, V. Bretin, J. Dalibard

Using two radio frequency pulses separated in time we perform an amplitude division interference experiment on a rubidium Bose-Einstein condensate. The presence of a quantized vortex, which is nucleated by stirring the condensate with a laser beam, is revealed by a dislocation in the fringe pattern.

Stanley J. Brodsky, Paul Hoyer, Nils Marchal, Stephane Peigne

The common view that structure functions measured in deep inelastic lepton scattering are determined by the probability of finding quarks and gluons in the target is not correct in gauge theory. We show that gluon exchange between the fast, outgoing partons and target spectators, which is usually assumed to be an irrelevant gauge artifact, affects the leadin

X. Bertou, P. Billoir, O. Deligny, C. Lachaud

The cosmic ray spectrum has been shown to extend well beyond 10^{20}eV. With nearly 20 events observed in the last 40 years, it is now established that particles are accelerated or produced in the universe with energies near 10^{21}eV. In all production models neutrinos and photons are part of the cosmic ray flux. In acceleration models (bottom-up models), t

M. A. Vasiliev

General properties of the theory of higher spin gauge fields in $AdS_4$ are discussed. Some new results on the 4d conformal higher spin gauge theory are announced. Talk given at the International Conference &#34;Quantization, Gauge Theory and Strings&#34; in memory of E.S.Fradkin, Moscow, June 5-10, 2000.

L. Feretti, R. Fusco-Femiano, G. Giovannini, F. Govoni

New radio data is presented for the rich cluster Abell 2163. The cluster radio emission is characterized by the presence of a radio halo, which is one of the most powerful and extended halos known so far. In the NE peripheral cluster region, we also detect diffuse elongated emission, which we classify as a cluster relic. The cluster A2163 is very hot and lum

F. De Fazio, M. R. Pennington

We consider the radiative transition $ϕ\to f_0 γ$, which is a sensitive probe of the nature of the $f_0(980)$ particle. Using the QCD sum-rule technique, we estimate the branching ratio of such decay mode to be: ${\cal B}(ϕ\to f_0 γ)=(2.7 \pm 1.1) ~ 10^{-4}$, in fair agreement with present experimental data. As for the structure of the $f_0$, the result sugg

Mohab Abou-Zeid, Harald Dorn

In a non-commutative field theory, the energy-momentum tensor obtained from the Noether method needs not be symmetric; in a massless theory, it needs not be traceless either. In a non-commutative scalar field theory, the method yields a locally conserved yet non-symmetric energy-momentum tensor whose trace does not vanish for massless fields. A non-symmetric

M. V. Polyakov, V. V. Vereshagin

We derive and analyse inequalities relating masses of the lightest pi-pi resonances (rho and sigma) to low energy couplings of the effective chiral Lagrangian in the limit of large number of colours.

L. E. Helseth, R. W. Hansen, E. I. Il&#39;yashenko, M. Baziljevich

Single crystalline films of bismuth-substituted ferrite garnets have been synthesized by the liquid phase epitaxy method where GGG substrates are dipped into the flux. The growth parameters are controlled to obtain films with in-plane magnetization and virtually no domain activity, which makes them excellently suited for magnetooptic imaging. The Faraday rot

N. Debergh, J. Van der Jeugt

The Lie superalgebra q(2) and its class of irreducible representations V_p of dimension 2p (p being a positive integer) are considered. The action of the q(2) generators on a basis of V_p is given explicitly, and from here two realizations of q(2) are determined. The q(2) generators are realized as differential operators in one variable x, and the basis vect

Olaf Stenull, Hans-Karl Janssen

We study nonlinear random resistor diode networks at the transition from the non percolating to the directed percolating phase. The resistor-like bonds and the diode-like bonds under forward bias voltage obey a generalized Ohm&#39;s law, $V \sim I^r$. Based on general grounds as symmetries and relevance we develop a field theoretic model. We focus on the ave

Naoki Shirakawa, Shin-Ichi Ikeda, Hirofumi Matsuhata, Hiroshi Bando

We investigated a method for obtaining a sintered bulk sample of single-phase Sr2MoO4, which has recently increased in importance due to its similarities to superconducting Sr2RuO4. We discovered that with the aid of Ti2O3 as a p(O2) buffer, high-purity Sr2MoO4 is successfully synthesized in a sealed tube. We confirmed the space group and determined the exac

S. Murugesh, Radha Balakrishnan

Lamb has identified a certain class of moving space curves with soliton equations. We show that there are two other classes of curve evolution that may be so identified. Hence three distinct classes of curve evolution are associated with a given integrable equation. The nonlinear Schrödinger equation is used to illustrate this explicitly.

Hidenori Sonoda

Despite its simplicity, the unitary gauge is not a popular choice for practical loop calculations in gauge theories, due to the lack of off-shell renormalizability. We study the renormalization properties of the off-shell Green functions of the elementary electron fields in the massive QED, in order to elucidate the origin and structure of the extra ultravio

Toru Aonishi, Masato Okada

In globally coupled oscillators, it is believed that strong higher harmonics of coupling functions are essential for multibranch entrainment (MBE), in which there exist many stable states, whose number scales as $\sim$ $O(\exp N)$ (where N is the system size). The existence of MBE implies the non-ergodicity of the system. Then, because this apparent breaking

Akio Sugamoto

Dynamical generation of 4d gauge theories and gravity at low energy from the 3d ones at high energy is studied, based on the fermion condensation mechanism recently proposed by Arkani-Hamed, Cohen and Georgi. For gravity, 4d Einstein gravity is generated from the multiple copy of the 3d ones, by referring to the two form gravity. Since the 3d Einstein action

Makoto Tsubota, Kenichi Kasamatsu, Masahito Ueda

We study the dynamics of vortex lattice formation of a rotating trapped Bose-Einstein condensate by numerically solving the two-dimensional Gross-Pitaevskii equation, and find that the condensate undergoes elliptic deformation, followed by unstable surface-mode excitations before forming a quantized vortex lattice. The origin of the peculiar surface-mode exc

A. N. Salgueiro, A. F. de R. de Toledo Piza, J. G. Peixoto de Faria

Decoherence effects associated to the damping of a tunneling two-level system are shown to dominate the tunneling probability at short times in strong coupling regimes in the context of a soluble model. A general decomposition of tunneling rates in dissipative and unitary parts is implemented. Master equation treatments fail to describe the model system corr

Peter Hoyer, Jan Neerbek

We prove that any exact quantum algorithm searching an ordered list of N elements requires more than \frac{1}π(\ln(N)-1) queries to the list. This improves upon the previously best known lower bound of {1/12}\log_2(N) - O(1). Our proof is based on a weighted all-pairs inner product argument, and it generalizes to bounded-error quantum algorithms. The current

Stephan I. Tzenov, Ronald C. Davidson

Building on the Radon transform of the Vlasov-Poisson equations, a macroscopic fluid model for the coherent beam-beam interaction has been developed. It is shown that the Vlasov equation, expressed in action-angle variables, can be reduced to a closed set of hydrodynamic (fluid) equations for the beam density and current velocity. The linearized one dimensio

Jasper Kirkby

A striking correlation has recently been observed between global cloud cover and the flux of incident cosmic rays. The effect of natural variations in the cosmic ray flux is large, causing estimated changes in the Earth&#39;s energy radiation balance that are comparable to those attributed to greenhouse gases from the burning of fossil fuels since the Indust

V. I. Drosdov

The 4-D theory with connection components Gamma^k_{mn} as field variables and module of squared curvature |R^k_{lmn}R^{lmn}_k| as Lagrangian is described. The Maxwell equations, the Lorentz condition and the gravity field equation, that agrees with Newton&#39;s theory, result from equations of motion.

K. Kubodera

There is growing interest in nuclear physics applications of effective field theory. I give a brief account of some of the latest developments in this area. I also describe interplay between this new approach and the traditional nuclear physics approach.

A. A. Raduta, P. Sarriguren, Amand Faessler, E. Moya de Guerra

A self-consistent formalism for the double beta decay of Fermi type is provided. The particle-particle channel of the two-body interaction is considered first in the mean field equations and then in the QRPA. The resulting approach is called the QRPA with a self-consistent mean field (QRPASMF). The mode provided by QRPASMF, does not collapse for any strength

Goeran Faeldt, Colin Wilkin

Data on the total cross sections for the pp -> pp eta, pn -> pn eta, and pn -> d eta reactions and the pp -> pp eta differential cross section near threshold are analysed in a one-meson-exchange model. After including initial and final-state nucleon-nucleon distortion, the magnitude and most of the energy dependence are well reproduced. It is found that the

A. Parreño, A. Ramos

We present an update of the One-Meson-Exchange (OME) results for the weak decay of s- and p-shell hypernuclei (Ref. Phys. Rev. C {\bf 56}, 339 (1997)), paying special attention to the role played by final state interactions between the emitted nucleons. The present study also corrects for a mistake in the inclusion of the $K$ and $K^*$ exchange mechanisms, w

H. Huebel

Using the spectrometer arrays GAMMASPHERE and EUROBALL a detailed spectroscopy of superdeformed 193Pb and 196Pb has been performed. In 193Pb nine superdeformed bands are now known and their quasiparticle assignments are discussed. In 196Pb evidence for an octupole vibrational excitation is presented.

Alejandro M. F. Rivas, Alfredo M. Ozorio de Almeida

We develop a semiclassical approximation for the spectral Wigner and Husimi functions in the neighbourhood of a classically unstable periodic orbit of chaotic two dimensional maps. The prediction of hyperbolic fringes for the Wigner function, asymptotic to the stable and unstable manifolds, is verified computationally for a (linear) cat map, after the theory

Mads Ipsen, Martin van Hecke

We study the dynamics of the one-dimensional complex Ginzburg Landau equation (CGLE) in the regime where holes and defects organize themselves into composite superstructures which we call zigzags. Extensive numerical simulations of the CGLE reveal a wide range of dynamical zigzag behavior which we summarize in a `phase diagram&#39;. We have performed a numer

Jerzy A. Zagrodzinski

A generalization of the addition relation for the Riemann theta functions and its limiting version for exponential functions appearing in soliton type equations are reported. The presented form seems to be particularly useful when processes in N+1, (N>1) space-time are analyzed. The commonly applied bilinear and trilinear approaches, restricted to the pure s

Roland Steinbauer

This work reports on the construction of a nonlinear distributional geometry (in the sense of Colombeau&#39;s special setting) and its applications to general relativity with a special focus on the distributional description of impulsive gravitational waves.

Jose A. Vallejo

We introduce an n-ary Lie algebroid canonically associated with a Nambu-Poisson manifold. We also prove that every Nambu-Poisson bracket defined on functions is induced by some differential operator on the exterior algebra, and characterize such operators. Some physical examples are presented.