December 1999 arXiv papers — page 24

M. J. Bünner, M. Ciofini, A. Giaquinta, R. Hegger

We apply a recently proposed method for the analysis of time series from systems with delayed feedback to experimental data generated by a CO_2 laser. The method is able to estimate the delay time with an error of the order of the sampling interval, while an approach based on the peaks of either the autocorrelation function, or the time delayed mutual inform

Kunihiko Kaneko, Chikara Furusawa

A dynamical systems scenario for developmental cell biology is proposed, based on numerical studies of a system with interacting units with internal dynamics and reproduction. Diversification, formation of discrete and recursive types, and rules for differentiation are found as a natural consequence of such a system. "Stem cells" that either prolifer

Mahendra K. Verma

withdrawn; Earlier versions of chao-dyn/9904020 & chao-dyn/9904021 have been combined into one paper.

James G. Ingalls, T. M. Bania, Adair P. Lane, Matthias Rumitz

The rotational transitions of carbon monoxide (CO) are the primary means of investigating the density and velocity structure of the molecular interstellar medium. Here we study the lowest four rotational transitions of CO towards high-latitude translucent molecular clouds (HLCs). We report new observations of the J = (4-3), (2-1), and (1-0) transitions of CO

Vincent Eke

A speedy pixon algorithm for image reconstruction is described. Two applications of the method to simulated astronomical data sets are also reported. In one case, galaxy clusters are extracted from multiwavelength microwave sky maps using the spectral dependence of the Sunyaev-Zel'dovich effect to distinguish them from the microwave background fluctuatio

A. Meszaros, Z. Bagoly, I. Horvath, L. G. Balazs

The counts-in-cells and the two-point angular correlation function method are used to test the randomnesses in the angular distributions of both the all gamma-ray bursts collected at BATSE Catalog, and also their three subclasses ("short", "intermediate", "long"). The methods elimate the non-zero sky-exposure function of BATSE instrum

Yurij V. Baryshev

This report continues recent Peebles-Turner debate "Is cosmology solved?" and considers the first results for Sandage's program for "Practical cosmology". A review of conceptual problems of modern cosmological models is given, among them: the nature of the space expansion; recession velocities of distant galaxies more than velocity of lig

R. S. Somerville, G. Lemson, Y. Sigad, A. Dekel

We study the biasing relation between dark-matter halos or galaxies and the underlying mass distribution, using cosmological $N$-body simulations in which galaxies are modelled via semi-analytic recipes. The nonlinear, stochastic biasing is quantified in terms of the mean biasing function and the scatter about it as a function of time, scale and object prope

M. Wold, M. Lacy, P. B. Lilje, S. Serjeant

We have observed the galaxy environments around a sample of 21 radio-loud, steep-spectrum quasars at 0.5<z<0.82, spanning several orders of magnitude in radio luminosity. The observations also include background control fields used to obtain the excess number of galaxies in each quasar field. The galaxy excess was quantified using the spatial galaxy-quasar c

Angelos Vourlidas, Prasad Subramanian, K. P. Dere, R. A. Howard

We examine the energetics of Coronal Mass Ejections (CMEs) with data from the LASCO coronagraphs on SOHO. The LASCO observations provide fairly direct measurements of the mass, velocity and dimensions of CMEs. Using these basic measurements, we determine the potential and kinetic energies and their evolution for several CMEs that exhibit a flux-rope morpholo

L. da Costa, M. Scodeggio, L. F. Olsen, C. Benoist

Candidate clusters of galaxies drawn from the sample identified from the moderately deep I-band data of the ESO Imaging Survey (EIS), have been used for follow-up optical/infrared imaging and spectroscopic observations. The observations were conducted to assess the nature of these candidates over a large range of redshifts. Currently, 163 EIS candidates have

Monica Colpi, Ulrich Geppert, Dany Page

We confront theoretical models for the rotational, magnetic, and thermal evolution of an ultra-magnetized neutron star, or magnetar, with available data on the Anomalous X-ray Pulsars (AXPs). We argue that, if the AXPs are interpreted as magnetars, their clustering of spin periods between 6 and 12 seconds, observed at present in this class of objects, their

Delphine Porquet, Jacques Dubau

Thanks to the new generation of X-ray satellites such as Chandra and XMM, high resolution and high sensitivity spectra are available. In particular, for the first time, the three most intense lines (resonance, intercombination and forbidden) of low charged (low Z) He-like ions are splitted for non solar plasmas. We present density, ionizing process and tempe

K. Hurley

Four Soft Gamma Repeaters (SGRs) have now been identified with certainty, and a fifth has possibly been detected. I will review their X-ray and gamma-ray properties in both outburst and quiescence. The magnetar model accounts fairly well for the observations of SGR1806-20 and SGR1900+14, but data are still lacking for SGR1627-41 and SGR0525-66. The locations

E. Verlinde, H. Verlinde

We study the low energy effective action $S$ of gravity, induced by integrating out gauge and matter fields, in a general class of Randall-Sundrum type string compactification scenarios with exponential warp factors. Our method combines dimensional reduction with the holographic map between between 5-d supergravity and 4-d large $N$ field theory. Using the c

Aneesh V. Manohar, Iain W. Stewart

A one-loop renormalization group analysis of the order v^2 relativistic corrections to the static QCD potential is presented. The velocity renormalization group is used to simultaneously sum ln(m/mv) and ln(m/mv^2) terms. The results are compared to previous calculations in the literature.

K. Bering

We find a new d-parameter family of ultra-local boundary Poisson brackets that satisfy the Jacobi identity. The two already known cases (hep-th/9305133, hep-th/9806249 and hep-th/9901112) of ultra-local boundary Poisson brackets are included in this new continuous family as special cases.

Matthew G. Baring

This paper summarizes highlights of the OG3.1, 3.2 and 3.3 sessions of the XXVIth International Cosmic Ray Conference in Salt Lake City, which were devoted to issues of origin/composition, acceleration and propagation.

Vesselin Petkov

A corollary of general relativity that the average velocity of light between two points in a gravitational field is anisotropic has been overlooked. It is shown that this anisotropy can be probed by an experiment which constitutes another test of general relativity.

D. Bazeia, F. A. Brito

We investigate several models of coupled scalar fields that present discrete Z_2, Z_2 x Z_2, Z_3 and other symmetries. These models support topological domain wall solutions of the BPS and non-BPS type. The BPS solutions are stable, but the stability of the non-BPS solutions may depend on the parameters that specify the models. The BPS and non-BPS states giv

Hoi-Kwong Lo

We study the amount of classical communication needed for distributed quantum information processing. In particular, we introduce the concept of &#34;remote preparation&#34; of a quantum state. Given an ensemble of states, Alice&#39;s task is to help Bob in a distant laboratory to prepare a state of her choice. We find several examples of an ensemble with an

A. Dobado, M. J. Herrero, J. R. Pelaez, E. Ruiz Morales

We present a unified analysis of the two main production processes of vector boson pairs at the LHC, VV-fusion and qqbar annihilation, in a minimal strongly interacting electroweak symmetry breaking sector. Using a unitarized electroweak chiral Lagrangian formalism and modeling the final V_L V_L strong rescattering effects by a form factor, we describe qqbar

Judith Cohen, David Hogg, Roger Blandford, Lennox Cowie

A redshift survey has been carried out in the region of the Hubble Deep Field North using the Low Resolution Imaging Spectrograph at the Keck Observatory. The resulting redshift catalog, which contains 671 entries, is a compendium of our own data together with published LRIS/Keck data. It is more than 92% complete for objects, irrespective of morphology, to

S. Das Sarma, Jaroslav Fabian, Xuedong Hu, Igor Zutic

Prospect of building spintronic devices in which electron spins store and transport information has attracted strong attention in recent years. Here we present some of our representative theoretical results on three fundamental aspects of spintronics: spin coherence, spin entanglement, and spin transport. In particular, we discuss our detailed quantitative t

Yakov Itin

The superstring and superbrane theories which include gravity as a necessary and fundamental part renew an interest to alternative representations of general relativity as well as the alternative models of gravity. We study the coframe teleparallel theory of gravity with a most general quadratic Lagrangian. The coframe field on a differentiable manifold is a

A. S. Evans, J. A. Surace, J. M. Mazzarella

High-resolution, CO(1-0) interferometry of the ultraluminous infrared galaxy IRAS 14348-1447 is presented. The merger system has a molecular gas mass of \~3x10^10 solar masses and a projected nuclear separation of 4.8 kpc (3.5&#34;), making it one of the most molecular gas-rich galaxies known and an ideal candidate for studying the intermediate stages of an

Karyn Le Hur

We derive a solvable resonant-level type model, to describe an impurity spin coupled to zero-energy bound states localized at the edge of a one dimensional d-wave superconductor. This results in a two-channel Kondo effect with a quite unusual low-temperature thermodynamics. For instance, the local impurity susceptibility yields a finite maximum at zero tempe

Ting-Wai Chiu

A transformation is devised to convert any lattice Dirac fermion operator into a Ginsparg-Wilson Dirac fermion operator. For the standard Wilson-Dirac lattice fermion operator, the transformed new operator is local, free of O(a) lattice artifacts, has correct axial anomaly in the trivial sector, and is not plagued by the notorious problems (e.g., additive ma

Leor Barack, Amos Ori

We present a method for calculating the self-force (the ``radiation reaction force'') acting on a charged particle moving in a strong field orbit in black hole spacetime. In this approach, one first calculates the contribution to the self-force due to each multipole mode of the particle's field. Then, the sum over modes is evaluated, subject to a certain reg

R. J. McLure, J. S. Dunlop, M. J. Kukula

A description is given of the method used to extract quasar host-galaxy parameters from the deep Hubble Space Telescope quasar images presented by McLure et al. (1999) and Dunlop et al. (2000). We then give the results of extensive testing of this technique on a wide range of simulated quasar+host combinations spanning the redshift range of our HST study (0.

F. Farchioni, Ph. de Forcrand, I. Hip, C. B. Lang

We re-analyze data from available finite-temperature QCD simulations near the chiral transition, with the help of Chiral Random Matrix Theory (chRMT). Statistical properties of the lowest-lying eigenvalues of the staggered Dirac operator for SU(3) lattice gauge theory with dynamical fermions are examined. We consider temperatures below, near, and above the c

M. Engelhardt, H. Reinhardt

A model for the infrared sector of Yang-Mills theory based on magnetic vortices represented by (closed) random surfaces is investigated using lattice Monte Carlo methods. The random surfaces are governed by a surface area action and a curvature action. The model generates a finite-temperature deconfinement transition; the coupling constants of the model can

T. Csorgo, A. T. Szerzo

A generic, model-independent method for the analysis of the two-particle short-range correlations is presented, that can be utilized to describe e.g. Bose-Einstein (HBT or GGLP), statistical, dynamical or other short-range correlation functions. The method is based on a data-motivated choice for the zero-th order approximation for the shape of the correlatio

F. Liu

Based on $(3.79\pm0.31)\times10^6 ~ψ&#39;$ data sets collected with the BES detector at BEPC, the recent $ψ&#39;$, $χ_{cJ}$ and $η_c$ results from BES are presented. Some results are compared with NRQCD.

J. Tamburino

This paper has been withdrawn

Alan Horwitz

Withdrawal Notice: SWJPAM does not allow articles it publishes to appear on archives. An updated version of this article along with new results, can be found at the author&#39;s web page: www.math.psu.edu/horwitz/papers.html

Hoi-Kwong Lo

We assess the potential of quantum cryptography as a technology. We highlight the fact that academia and real world have rather different perspectives and interests. Then, we describe the various real life forces (different types of users, vendors of crypto-systems, conventional cryptographers, governments) behind the decision of the adoption (or rejection)

B. Kraus, J. I. Cirac, S. Karnas, M. Lewenstein

We analyze the separability properties of density operators supported on $\C^2\otimes \C^N$ whose partial transposes are positive operators. We show that if the rank of $ρ$ equals N then it is separable, and that bound entangled states have rank larger than N. We also give a separability criterion for a generic density operator such that the sum of its rank

S. Mancini, A. M. Martins, P. Tombesi

We propose the use of a trapped electron to implement quantum logic operations. The fundamental controlled-NOT gate is shown to be feasible. The two quantum bits are stored in the internal and external (motional) degrees of freedom.

L. F. Santos, C. O. Escobar

There is a striking convergence between Burgers turbulence and the continuous spontaneous localization [CSL] model of quantum mechanics. In this paper, we exploit this analogy showing the similarities in the physics of these two apparently unrelated problems. It is hoped that the kind of analogy we introduce here may lead to important developments in both ar

Waldemar Puszkarz

We discuss Staruszkiewicz&#39;s nonlinear modification of the Schrödinger equation. It is pointed out that the expression for the energy functional for this modification is not unique as the field-theoretical definition of energy does not coincide with the quantum-mechanical one. As a result, this modification can be formulated in three different ways depend

S. Bose, M. B. Plenio, V. Vedral

Ideal dense coding protocols allow one to use prior maximal entanglement to send two bits of classical information by the physical transfer of a single encoded qubit. We investigate the case when the prior entanglement is not maximal and the initial state of the entangled pair of qubits being used for the dense coding is a mixed state. We find upper and lowe

W. T. Geng

A simple, approximate relation is found between the total energy of a free atom and its atomic number: E ~= -Z^{2.411}. The existence of this index is inherent in the Coulomb and many-body nature of the electron-electron interaction in the atomic system and cannot be fabricated from the existing fundamental physical constants.

I. A. Pshenichnov

A model of electromagnetic interaction of relativistic heavy ions which makes it possible to calculate the inclusive and exclusive characteristics of such interactions is presented. The multistep model includes (1) the single and double virtual photon absorption by a nucleus, (2) intranuclear cascades of produced hadrons and (3) statistical decay of excited

R. Wyss

The properties of T=0 neutron-proton correlations are discussed within the frame work of different model calculations. Single-j shell calculations reveal that the T=0 correlations remain up to the highest frequencies. They are more complex and cannot be restricted to L=0 pairs only. Whereas it may be difficult to find clear evidence for T=0 pairing at low sp

F. R. Xu, W. Satula, R. Wyss

The signature inversion in the πh11/2 \otimes νh11/2 rotational bands of odd-odd Cs and La isotopes and the πh11/2 \otimes νi13/2 bands of odd-odd Tb, Ho and Tm nuclei is investigated using pairing and deformation self consistent mean field calculations. The model can rather satisfactorily account for the anomalous signature splitting, provided that spin ass

J. Ryckebusch, S. Janssen, W. Van Nespen, D. Debruyne

The effect of tensor nucleon-nucleon correlations upon exclusive and semi-exclusive electronuclear reactions is studied. Differential cross sections for the semi-exclusive ^{16}O(e,e&#39;p) and exclusive ^{16}O(e,e&#39;pn) processes are computed by explicitly evaluating the dynamical electromagnetic coupling to a tensor correlated nucleon pair. In both react

V. F. Dmitriev, V. B. Telitsin

The contribution of many-body effects to the nuclear anapole moment were studied earlier in [1]. Here, more accurate calculation of the many-body contributions is presented, which goes beyond the constant density approximation for them used in [1]. The effects of pairing are now included. The accuracy of the short range limit of the parity violating nuclear

B. Blankleider, A. N. Kvinikhidze

Authors of Phys. Rev. C 60, 062201 (1999) presented a calculation of the electromagnetic form factors of the nucleon using a diquark ansatz in the relativistic three-quark Faddeev equations. In this Comment it is pointed out that the calculations of these form factors stem from a three-quark bound state current that contains overcounted contributions. The co

A. Schiller, M. Guttormsen, E. Melby, J. Rekstad

Complementary measurements have been performed for the level density and gamma strength function in 162-Dy using inelastic 3-He scattering. Comparing these results to previous measurements using the 163-Dy(3-He,alpha) reaction, reveals that the measured quantities above 1.5 MeV do not depend significantly on the nuclear reaction chosen.

D. Damanik, P. Stollmann

We prove that a strong form of dynamical localization follows from a variable energy multi-scale analysis. This abstract result is applied to a number of models for wave propagation in disordered media.

Kevin Corlette, Robert M. Wald

Existence of an infinite sequence of harmonic maps between spheres of certain dimensions was proven by Bizon and Chmaj. This sequence shares many features of the Bartnik-McKinnon sequence of solutions to the Einstein-Yang-Mills equations as well as sequences of solutions that have arisen in other physical models. We apply Morse theory methods to prove existe

Vadim E. Levit, Eugen Mandrescu

The stability number of a graph G, is the cardinality of a stable set of maximum size in G. If the stability number of G remains the same upon the addition of any edge, then G is called $α^{+}$-stable. G is a König-Egervary graph if its order equals the sum of its stability number and the cardinality of a maximum matching. In this paper we characterize $α^{+

P. Moussa, S. Marmi

The continued fraction expansion of the real number $x=a_0+x_0, a_0\in {\ZZ},$ is given by $0\leq x_n<1, x_{n}^{-1}=a_{n+1}+ x_{n+1}, a_{n+1}\in {\NN},$ for $n\geq 0.$ The Brjuno function is then $B(x)=\sum_{n=0}^{\infty}x_0x_1... x_{n-1}\ln(x_n^{-1}),$ and the number $x$ satisfies the Brjuno diophantine condition whenever $B(x)$ is bounded. Invariant circle

S. Marmi, P. Moussa, J. -C. Yoccoz

The Brjuno function arises naturally in the study of one--dimensional analytic small divisors problems. It belongs to $\hbox{BMO}({\Bbb T}^{1})$ and it is stable under Hölder perturbations. It is related to the size of Siegel disks by various rigorous and conjectural results. In this work we show how to extend the Brjuno function to a holomorphic function on

Thomas Cooper, David Mond, Roberta Wik Atique

We construct all codimension 1 multi-germs of maps (k^n,T)-->(k^p,0) with n > p-2, (n,p) nice dimensions, k = R or C, by augmentation and concetenation operations, starting from mon-germs (|T|=1). As an application, we prove general results for multi-germs of corank <2: every one has a real form with real perturbation carrying the vanishing homology of the c

Spencer Bloch, Hélène Esnault

Let $f: X \to S$ be a smooth morphism in characteristic 0, and let $(E, \nabla_{X/S})$ be a relative regular connection. We define a cohomology of relative differential characters on $X$ which receives classes of $(E, \nabla_{X/S})$. It says in particular that the partial vanishing of the trace of the iterated Atiyah classs can be made canonical. While appli

Diane Maclagan, Rekha R. Thomas

The toric Hilbert scheme is a parameter space for all ideals with the same multi-graded Hilbert function as a given toric ideal. Unlike the classical Hilbert scheme, it is unknown whether toric Hilbert schemes are connected. We construct a graph on all the monomial ideals on the scheme, called the flip graph, and prove that the toric Hilbert scheme is connec

Imre Tuba, Hans Wenzl

We give a complete classification of simple representations of the braid group B_3 with dimension $\leq 5$ over any algebraically closed f ield. In particular, we prove that a simple d-dimensional representation $ρ: B_3 \to GL(V)$ is determined up to isomorphism by the eigenvalues $λ_1, λ_2, ..., λ_d$ of the image of the generators for d=2,3 and a choice of

Arkady Berenstein, Andrei Zelevinsky

We obtain a family of explicit &#34;polyhedral&#34; combinatorial expressions for multiplicities in the tensor product of two simple finite-dimensional modules over a complex semisimple Lie algebra. Here &#34;polyhedral&#34; means that the multiplicity in question is expressed as the number of lattice points in some convex polytope. Our answers use a new com

A. V. Bolsinov, I. A. Taimanov

For any toric automorphism with only real eigenvalues a Riemannian metric with an integrable geodesic flow on the suspension of this automorphism is constructed. A qualitative analysis of such a flow on a three-solvmanifold constructed by the authors in math.DG/9905078 is done. This flow is an example of the geodesic flow, which has vanishing Liouville entro

Fritz Gesztesy, Konstantin A. Makarov

We explore connections between Krein&#39;s spectral shift function $ξ(λ,H_0,H)$ associated with the pair of self-adjoint operators $(H_0,H)$, $H=H_0+V$ in a Hilbert space $\calH$ and the recently introduced concept of a spectral shift operator $Ξ(J+K^*(H_0-λ-i0)^{-1}K)$ associated with the operator-valued Herglotz function $J+K^*(H_0-z)^{-1}K$, $\Im(z)>0$ in

Alan Mason

A stochastic flow is constructed on a frame bundle adapted to a Riemannian foliation on a compact manifold. The generator A of the resulting transition semigroup is shown to preserve the basic functions and forms, and there is an essentially unique strictly positive smooth function phi satisfying A^* phi = 0. This function is used to perturb the metric, and

Klaus Junemann, Olaf Lechtenfeld

The existence of a ground ring of ghost number zero operators in the chiral BRST cohomology of the N=2 string is used to derive an infinite set of Ward identities for the closed-string scattering amplitudes at arbitrary genus. These identities are sufficient to rederive the well known vanishing theorem for loop amplitudes with more than three external legs.

R. Endo, M. Koseki

We provide a gauge covariant formalism of the canonically quantized theory of spin-3/2 Rarita-Schwinger gauge field. The theory admits a quantum gauge transformation by which we can shift the gauge fixing parameter. The quantum gauge transformation does not change the BRST charge. Thus, the physical Hilbert space is trivially independent of the gauge fixing

Rong-Gen Cai, Nobuyoshi Ohta

For spaces which are not asymptotically anti-de Sitter where the asymptotic behavior is deformed by replacing the cosmological constant by a dilaton scalar potential, we show that it is possible to have well-defined boundary stress-energy tensors and finite Euclidean actions by adding appropriate surface counterterms. We illustrate the method by the examples

J. de Boer, E. Verlinde, H. Verlinde

We propose a direct correspondence between the classical evolution equations of 5-d supergravity and the renormalization group (RG) equations of the dual 4-d large $N$ gauge theory. Using standard Hamilton-Jacobi theory, we derive first order flow equations for the classical supergravity action $S$, that take the usual form of the Callan-Symanzik equations,

Matthew J. Slater

Using the ADHM instanton calculus, we evaluate the one-instanton contribution to the low-energy effective prepotential of N=2 supersymmetric SU(N) Yang-Mills theory with N_F flavors of hypermultiplets in the fundamental representation and a hypermultiplet in the symmetric rank two tensor representation. For N_F<N-2, when the theory is asymptotically free, ou

M. Rooman, Ph. Spindel

Using the Chern-Simon formulation of (2+1) gravity, we derive, for the general asymptotic metrics given by the Fefferman-Graham-Lee theorems, the emergence of the Liouville mode associated to the boundary degrees of freedom of (2+1) dimensional anti de Sitter geometries.

Shahrokh Parvizi, Amir H. Fatollahi

It is argued that quantum traveling of D-particles presents the ``joining-splitting&#39;&#39; processes of field theory Feynman graphs. The amplitudes in $d$ dimensions can be corresponded with those of a $d+2$ dimensional theory in the Light-Cone frame. It is shown that this Light-Cone formulation enables to study processes with arbitrary longitudinal momen

E. Torrente-Lujan

We consider the effect of a random magnetic field in the convective zone of the Sun on resonant neutrino spin-flavour oscillations. The expected signals in the different experiments (SK, GALLEX-SAGE,Homestake) are obtained as a function of the level of noise, regular magnetic field and neutrino mixing parameters. Previous results obtained for small mixing an

M. Carena, S. Heinemeyer, C. E. M. Wagner, G. Weiglein

We suggest new benchmark scenarios for the Higgs-boson search at LEP2. Keeping m_t and M_SUSY fixed, we improve on the definition of the maximal mixing benchmark scenario defining precisely the values of all MSSM parameters such that the new m_h^max benchmark scenario yields the parameters which maximize the value of m_h for a given tan(beta). The correspond

A. M. Gavrilik, N. Z. Iorgov

In the approach to hadronic flavour symmetries based on the q-algebras U_q(su_N) and proved to be realistic, the known construction of U_q(su_N) in terms of anyonic oscillators residing on 2d lattice is utilized. Anyonic Fock-like realization of basis state vectors is given for baryons (3/2)^+ from the 10-plet of U_q(su_3) embedded, via 20-plet of U_q(su_4),

M. Ciuchini, S. E. Derkachov, J. A. Gracey, A. N. Manashov

We present the formalism to calculate d-dimensional critical exponents in QCD in the large N_f expansion where N_f is the number of quark flavours. It relies in part on demonstrating that at the d-dimensional fixed point of QCD the critical theory is equivalent to a non-abelian version of the Thirring model. We describe the techniques used to compute critica

Elena Gubankova

Light-front QCD is studied by the method of flow equations. Dynamical gluon mass is generated, which evolves with the cut-off according to renormalization group equation. Eliminating by flow equations the quark gluon coupling with the dynamical gluon mode, one obtains an effective interaction between quark and antiquark which exibits the Coulomb and confinin

Kiwoon Choi

A slow-rolling scalar field (Quintessence) has been proposed as the origin of accelerating universe at present. We discuss some features of quintessence, particularly those related with the {\it flatness} of its potential. We distinguish two types of quintessences, a metrical quintessence which couples to the particle physics sector {\it only} through the mi

S. Lola

We study single superparticle productions at the linear collider, putting particular emphasis on resonant processes. We find that there exists a wide region of model parameters where single chargino and neutralino productions dominate over R-violating fermion-antifermion final states. For certain values of mu and M_2 it is possible to produce even the heavie

G. K. Yeghiyan

The problem of the lightest Higgs boson mass in the next-to-minimal supersymmetric standard model (NMSSM) is investigated. Assuming the validity of the perturbation theory up to unification scales and using the recent experimental results for the top quark mass, the restrictions on the NMSSM coupling constants are obtained. These restrictions are used to mak

Lian You Shan, Shou Hua Zhu

We have calculated the decay width of the process $t \to \tilde{g} \tilde{t}_1$ including one loop QCD corrections. We found that the decay width of the such process could be comparable with that of the standard channel $t \to b W^+$, and, its QCD correction could enhance the widths over 30% in a very large mass range of the lighter stop.

Michael Creutz

Domain-wall Fermions represent a recent lattice approach to chiral symmetry that is receiving considerable attention. The method is presented in a somewhat unconventional manner, in terms of a ladder molecule subjected to a magnetic field. Speculations are made on extending the formalism to multiple species.

M. Faber, J. Greensite, S. Olejnik, D. Yamada

We address two questions related to the procedure of identifying center vortices based on center projection in maximal center gauge: 1. How does the procedure work, why is it expected to locate center vortices relevant for confinement, and why does it in some cases fail, on lattice configurations preconditioned in a special way? 2. Does the mechanism work th

The WA102 Collaboration, D. Barberis

The reactions pp -> pf (X0) ps, where X0 is observed decaying to pi0pi0pi0pi0, pi+pi-pi0pi0 and pi+pi-pi+pi-, have been studied at 450 GeV/c. There is evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870) in the pi+pi-pi0pi0 and pi+pi-pi+pi- final states. The f2(1950) is consistent with being a single resonance with a dominant f2(1270)pipi d

Fumihiko Takasaki

Status of the KEKB accelerator and the detector, BELLE, is reported. The construction of the 3.5 Gev x 8 GeV electron-positron collider, and the solenoid detector, BELLE, was completed in December, 1998. The commissioning of them has been made since then. The BELLE detector has observed the first hadronic event from the beam collision on Jun 1, 1999. The ach

C. Chicone, B. Mashhoon, D. G. Retzloff

We define the general Hill system and briefly analyze its dynamical behavior. A particular Hill system representing the interaction of a Keplerian binary system with a normally incident circularly polarized gravitational wave is discussed in detail. In this case, we compute the Poincaré-Melnikov function explicitly and determine its zeros. Moreover, we provi

Martin Rainer

The bosonic content of string theory in curved background of multidimensional structure with p-branes has a systematic geometrical description as an effective sigma-model of gravity in lower dimension (say 3+1) with additional interacting dilatonic and p-brane fields. If the target-space is locally symmetric, solutions with intersecting p-branes can be found

Bernd Bruegmann

Numerical relativity is finally approaching a state where the evolution of rather general (3+1)-dimensional data sets can be computed in order to solve the Einstein equations. After a general introduction, three topics of current interest are briefly reviewed: binary black hole mergers, the evolution of strong gravitational waves, and shift conditions for ne

M. A. Castagnino H. Giacomini, L. Lara

In this paper we study the dynamical behaviour of a simple cosmological model defined by a spatially flat Robertson-Walker geometry, conformally coupled with a massive scalar field. We determine a Lyapunov-like function for the non-linear evolution equations. From this function we prove that all the stationary solutions are unstable. We also show that all in

M. I. Wanas, M. E. Kahil

Paths in an appropriate geometry are usually used as trajectories of test particles in geometric theories of gravity. It is shown that non-symmetric geometries possess some interesting quantum features. Without carrying out any quantization schemes, paths in such geometries are naturally quantized. Two different non-symmetric geometries are examined for thes

George Jorjadze, Wlodzimierz Piechocki

We analyze particle dynamics on $N$ dimensional one-sheet hyperboloid embedded in $N+1$ dimensional Minkowski space. The dynamical integrals constructed by $SO_\uparrow (1,N)$ symmetry of spacetime are used for the gauge-invariant Hamiltonian reduction. The physical phase-space parametrizes the set of all classical trajectories on the hyperboloid. In quantum

Jonathan Thornburg

This is the second in a series of papers describing a 3+1 computational scheme for the numerical simulation of dynamic black hole spacetimes. We discuss the numerical time-evolution of a given black-hole-containing initial data slice in spherical symmetry. We avoid singularities via the &#34;black-hole exclusion&#34; or &#34;horizon boundary condition&#34; t

A. Kazaryan, Y. Wang, S. A. Dregia, Bruce R. Patton

We study the dynamics and morphology of grain growth with anisotropic energy and mobility of grain boundaries using a generalized phase field model. In contrast to previous studies, both inclination and misorientation of the boundaries are considered. The model is first validated against exact analytical solutions for the classical problem of an island grain

M. R. Norman, M. Randeria, B. Janko, J. C. Campuzano

If high temperature cuprate superconductivity is due to electronic correlations, then the energy difference between the normal and superconducting states can be expressed in terms of the occupied part of the single particle spectral function. The latter can, in principle, be determined from angle resolved photoemission (ARPES) data. As a consequence, the ene

G. Sergeeva

We discuss the scenario of superconducing transition for quasi two dimension HTS with spin fluctuation pairing mechanism. At mean field temperature of 2D superconducting transition the interaction of fluctuation spin waves with holes in copper-oxigen planes leads to the pairing of holes and to the fluctuation generation of superconducting regions, and also t

Andreas Kraus, Artur Erbe, Robert H. Blick

We demonstrate how to build a vibrating wire resonator for phonon excitation in liquid helium. The resonator is designed as a nanoscopic mechanically flexible beam machined out of a semiconductor/metal-hybrid. Quenching of the mechanical resonance around 100 MHz by phonon excitation in liquid ^4He at 4.2 K is shown. First measurements operating the nano-reso

Rodolfo A. Jalabert

Semiclassical methods are extremely valuable in the study of transport and thermodynamical properties of ballistic microstructures. By expressing the conductance in terms of classical trajectories, we demonstrate that quantum interference phenomena depend on the underlying classical dynamics of non-interacting electrons. In particular, we are able to calcula

G. M. Zhao, V. Smolyaninova, W. Prellier, H. Keller

We report measurements of the resistivity in the ferromagnetic state of epitaxial thin films of La_{1-x}Ca_{x}MnO_{3} and the low temperature specific heat of a polycrystalline La_{0.8}Ca_{0.2}MnO_{3}. The resistivity below 100 K can be well fitted by ρ- ρ_{o} = E ω_{s}/sinh^{2}(\hbar ω_{s}/2k_{B}T) with \hbar ω_{s}/k_{B} \simeq 100 K and E being a constant.

Jacques Duran

We observe ripples forming on the surface of a granular powder in a container submitted from below to a series of brief and distinct shocks. After a few taps, the pattern turns out to be stable against any further shock of the same amplitude. We find experimentally that the characteristic wavelength of the pattern is proportional to the amplitude of the shoc

Sasuke Miyazima, Youngki Lee, Tomomasa Nagamine, Hiroaki Miyajima

We study the frequency distribution of family names. From a common data base, we count the number of people who share the same family name. This is the size of the family. We find that (i) the total number of different family names in a society scales as a power-law of the population, (ii) the total number of family names of the same size decreases as the si

V. N. Bogomolov

A simple model of the molecular crystal of $N$ atoms as a statistical mixture in real space of $NX$ atoms in excited and $N(1-X)$ atoms in well localized ground state is considered. The phase coherence of the atomic wave functions is suppose to be absent. A bond energy of crystal is supposed to be a result of the pair interaction of $NX$ excited atoms. These

Kirill Katsov, John D. Weeks

In important early work, Stell showed that one can determine the pair correlation function h(r) of the hard sphere fluid for all distances r by specifying only the &#34;tail&#34; of the direct correlation function c(r) at separations greater than the hard core diameter. We extend this idea in a very natural way to potentials with a soft repulsive core of fin