April 1999 arXiv papers — page 5

A. Levin, M. Olshanetsky

We describe non-autonomous Hamiltonian systems coming from the Hitchin integrable systems. The Hitchin integrals of motion depend on the W-structures of the basic curve. The parameters of the W-structures play the role of times. In particular, the quadratic integrals dependent on the complex structure (W_2-structure) of the basic curve and times are coordina

David P. Roberts

In this paper we give a conjectural refinement of the Davenport-Heilbronn theorem on the density of cubic field discriminants. We explain how this refinement is plausible theoretically and agrees very well with computational data.

Christian Borgs, Jennifer Chayes, Remco van der Hofstad, Gordon Slade

We introduce a mean-field model of lattice trees based on embeddings into $\Z^d$ of abstract trees having a critical Poisson offspring distribution. This model provides a combinatorial interpretation for the self-consistent mean-field model introduced previously by Derbez and Slade, and provides an alternate approach to work of Aldous. The scaling limit of t

L. Brambila-Paz, V. Mercat, P. E. Newstead, F. Ongay

Let $X$ be a non-singular algebraic curve of genus $g$. We prove that the Brill-Noether locus $\bns $ is non-empty if $d= nd&#39; +d&#39;&#39; $ with $0< d&#39;&#39; <2n$, $1\le s\le g$, $d&#39;\geq (s-1)(s+g)/s $, $n\leq d&#39;&#39;+(n-k)g$, $(d&#39;&#39;,k)\ne(n,n)$. These results hold for an arbitrary curve of genus $\ge 2$, and allow us to construct a re

Yi Hu, Sean Keel

We give a short proof of W{\lodarczyk&#39;s theorem that any birational map between smooth projective varieties in characteristic zero is a composition of weighted blowups and blowdowns.

V. Hinich

Let $k$ be a field of characteristic zero, $\CO$ be a dg operad over $k$ and let $A$ be an $\CO$-algebra. In this note we define formal deformations of $A$, construct the deformation functor $$\Def_A:\dgar(k)\to\simpl$$ from the category of artinian local dg algebras to the category of simplicial sets. In the case $\CO$ and $A$ are non-positively graded, we

Michel Brion, Patrick Polo

For a semisimple adjoint algebraic group $G$ and a Borel subgroup $B$, consider the double classes $BwB$ in $G$ and their closures in the canonical compactification of $G$: we call these closures large Schubert varieties. We show that these varieties are normal and Cohen-Macaulay; we describe their Picard group and the spaces of sections of their line bundle

Tao Jiang, Douglas B. West

The chromatic sum of a graph is the smallest sum of colors among all proper colorings with natural numbers. The strength is the minimum number of colors needed to achieve the chromatic sum. We construct for each positive integer k a tree with strength k that has maximum degree only 2k-2. The result is best possible.

Klaus Mohnke

For a given embedded Lagrangian in the complement of a complex hypersurface we show existence of a holomorphic disc in the complement having boundary on that Lagrangian.

Nathan F. Lepora, T. W. B. Kibble

We analyse symmetry breaking in the Weinberg-Salam model paying particular attention to the underlying geometry of the theory. In this context we find two natural metrics upon the vacuum manifold: an isotropic metric associated with the scalar sector, and a squashed metric associated with the gauge sector. Physically, the interplay between these metrics give

Nathan F. Lepora, T. W. B. Kibble

We classify the spectrum, family structure and stability of Nielsen-Olesen vortices embedded in a larger gauge group when the vacuum manifold is related to a symmetric space.

Jaume Garriga, V. F. Mukhanov

We extend the theory of cosmological perturbations to the case when the ``matter&#39;&#39; Lagrangian is an arbitrary function of the scalar field and its first derivatives. In particular, this extension provides a unified description of known cases such as the usual scalar field and the hydrodynamical perfect fluid. In addition, it applies to the recently p

Mikhail S. Volkov, Dieter Maison

A static, spherically symmetric and purely magnetic solution of the Einstein-Yang-Mills-Dilaton theory, found previously by numerical integration is shown to obey a system of first order Bogomol&#39;nyi equations. As common for such equations, there is a tight relation to supersymmetry, in the present case to the N=4 gauged SU(2)$\times$SU(2) supergravity of

A. Campbell-Smith, N. E. Mavromatos

We investigate and contrast the non-perturbative infra red structure of N=1 and N=2 supersymmetric non-compact U(1) gauge field theory in three space-time dimensions with N matter flavours. We study the Dyson-Schwinger equations in a general gauge using superfield formalism; this ensures that supersymmetry is kept manifest, though leads to spurious infra red

Thomas Appelquist, Andrew Cohen, Martin Schmaltz, Robert Shrock

Recently, a new constraint on the structure of a wide class of strongly coupled field theories has been proposed. It takes the form of an inequality limiting the number of degrees of freedom in the infrared description of a theory to be no larger than the number of underlying, ultraviolet degrees of freedom. Here we apply this inequality to chiral gauge theo

J. A. Mignaco, C. Sigaud, A. R. da Silva, F. J. Vanhecke

In this work we examine generalized Connes-Lott models on the two-sphere. The Hilbert space of the continuum spectral triple is taken as the space of sections of a twisted spinor bundle, allowing for nontrivial topological structure (magnetic monopoles). The finitely generated projective module over the full algebra is also taken as topologically non-trivial

Marek Rogatko

Using a sigma model formulation of the field equations as on a two-dimensional manifold we provide the proof of a black hole uniqueness solution in N=4, d=4 supergravity subject to certain boundary conditions. We considered the black hole solutions both in SU(4) and SO(4) versions of the underlying theory.

Miao Li

We investigate the consequence of the energy-momentum conservation law for the holographic S-matrix from AdS/CFT correspondence. It is shown that the conservation law is not a natural consequence of conformal invariance in the large N limit. We predict a new singularity for the four point correlation function of a marginal operator. Only the two point scatte

Guido Cognola, Sergio Zerbini

It is shown that the multiplicative anomaly in the vector-axial-vector model, which apparently has nothing to do with the breaking of classical current symmetries, nevertheless is strictly related to the well known consistent and covariant anomalies.

Graciela Gelmini, Paolo Gondolo, Gabriele Varieschi

We compare the leading and next-to-leading order QCD predictions for the flux of atmospheric muons and neutrinos from decays of charmed particles. We find that the full NLO lepton fluxes can be approximated to within 10% by the Born--level fluxes multiplied by an overall factor of 2.2-2.4, which depends slightly on the PDF. This supports the approach in Thun

R. D. Peccei

I review some of the salient issues connected to CP-violation and weak decays. In particular, I focus on recent and forthcoming tests of the CKM model and discuss the accuracy one can expect to achieve in B-decays for the parameters of this model.

Ll. Ametller, J. Kambor, M. Knecht, P. Talavera

The processes $γγ\toπ^0π^0π^0$ and $γγ\to π^+ π^- π^0$ are considered in Generalized Chiral Perturbation theory, in view of their potential sensitivity to the mechanism of spontaneous breaking of chiral symmetry and to various counterterms. The amplitudes are computed up to order ${\cal O}(p^6)$. The event production rates are estimated for the Daphne $ϕ$-Fa

G. J. Gounaris, J. Layssac, P. I. Porfyriadis, F. M. Renard

We study the helicity amplitudes and the observables of the process $γγ\to γZ$ at high energy. As in the case of the $γγ\to γγ$ process studied before, the relevant diagrams in the standard model (SM) involve $W$, charged quark and lepton loops; while in SUSY we also have contributions from chargino, and charged sfermion or Higgs loop diagrams. Above 250 GeV

Hsiang-nan Li

We develop perturbative QCD factorization theorems for inclusive b-hadron decays, in which radiative corrections characterized by the hadronic scale, the b-hadron mass, and the W boson mass are absorbed into a heavy hadron distribution function, a hard b quark decay amplitude, and a &#34;harder&#34; function, respectively. Double logarithmic corrections asso

Gerald B. Cleaver

Common to many classes of three family SU(3)_C x SU(2)_L x U(1)_Y string models are an additional anomalous U(1)_A and numerous, often fractionally charged, exotic particles beyond the minimal supersymmetric standard model (MSSM). I present one string model with both of these properties. Using this model as an example, I show how sometimes (near) string scal

Tanmoy Bhattacharya, Shailesh Chandrasekharan, Rajan Gupta, Weonjong Lee

We extend the application of axial Ward identities to calculate $b_A, b_P$ and $b_T$, coefficients that give the mass dependence of the renormalization constants of the corresponding bilinear operators in the quenched theory. The extension relies on using operators with non-degenerate quark masses. It allows a complete determination of the O(a) improvement c

E. -M. Ilgenfritz, S. Thurner, H. Markum, M. M&#34;uller-Preussker

Renormalization group (RG) smoothing is employed on the lattice to investigate and to compare the monopole structure of the SU(2) vacuum as seen in different gauges (maximally Abelian (MAG), Polyakov loop (PG) and Laplacian gauge (LG)). Physically relevant types of monopoles (LG and MAG) are distinguished by their behavior near the deconfining phase transiti

NuTeV Collaboration, R. A. Johnson, T. Adams, A. Alton

We report the measurement of sin^2 theta_W in nu N deep inelastic scattering from the NuTeV experiment. By using separate neutrino and anti-neutrino beams, NuTeV is able to determine sin^2 theta_W with smaller systematic and similar or smaller statistical errors when compared to previous neutrino experiments. NuTeV measures sin^2 theta_W (on-shell) = 0.2253

2 collaboration

In experiments with the CMD-2 detector at the VEPP-2M electron-positron collider at Novosibirsk about 150000 $e^+e^-\toπ^+π^-$ events were recorded in the center-of-mass energy range from 0.61 up to 0.96 GeV. The result of the pion form factor measurement with a 1.4% systematic error is presented. The following values of the $ρ$-meson and $ρ-ω$ interference

John Ellis, N. E. Mavromatos, D. V. Nanopoulos

We argue that quantum-gravitational fluctuations in the space-time background give the vacuum non-trivial optical properties that include diffusion and consequent uncertainties in the arrival times of photons, causing stochastic fluctuations in the velocity of light ``in vacuo&#39;&#39;. Our proposal is motivated within a Liouville string formulation of quan

Luis P. Chimento, Alejandro S. Jakubi

The reheating process for the inflationary scenario is investigated phenomenologically. The decay of the oscillating massive inflaton field into light bosons is modeled after an out of equilibrium mixture of interacting fluids within the framework of irreversible thermodynamics. Self-consistent, analytic results for the evolution of the main macroscopic magn

C. Espinoza, M. Ruiz-Altaba

We review the idea of stretched horizon for extremal black holes in supersymmetric string theories, and we compute it for non-supersymmetric black holes in four dimensions. Only for small masses of the order of the Veneziano wavelength is the stretched horizon bigger than the event horizon.

Yongge Ma, Canbin Liang, Zhiquan Kuang

The structure of the phase boundary between degenerate and non-degenerate regions in Ashtekar&#39;s gravity has been studied by Bengtsson and Jacobson who conjectured that the &#34;phase boundary&#34; should always be null. In this paper, we reformulate the reparametrization procedure in the mapping language and distinguish a phase boundary from its image. I

H. C. Rosu

If at least some Wheeler-DeWitt solutions can be interpreted as zero-energy resonances then the total s-wave cross section of the corresponding quantum universes is infinite

Walter Eaves

This paper describes an architecture for a distributing processing system that would allow remote procedure calls to invoke other services as messages are passed between clients and servers. It proposes that an additional class of data processing objects be located in the software communications channel. The objects in this channel would then be used to enfo

Haranath Ghosh

We study the effect of Zeeman magnetic field in the superconducting phase with two component order parameter scenario, such as, $d_{x^2-y^2} + e^{iθ}α$, where $α= d_{xy}, s$. This scenario is equivalent to applying magnetic field parrllel to Cu-O planes. In a weak magnetic field, which does not cause much change to the predominant d-wave, supresses the minor

A. Greco, R. Zeyher

Using a large-N expansion we present and solve the linearized equation for the superconducting gap for a generalized t-J model which also contains phonons within a Holstein model. The leading Tc has d-wave symmetry with phonons giving a positive contribution to Tc. The corresponding isotope coefficient is very small at optimal doping and increases towards th

Mohsen Sabouri-Ghomi, Slava Ispolatov, Martin Grant

Using Brownian dynamics, we simulate the fracture of polymer interfaces reinforced by diblock connector chains. We find that for short chains the interface fracture toughness depends linearly on the degree of polymerization $N$ of the connector chains, while for longer chains the dependence becomes $N^{3/2}$. Based on the geometry of initial chain configurat

Pengcheng Dai, H. Y. Hwang, Jiandi Zhang, J. A. Fernandez-Baca

Inelastic neutron scattering was used to systematically investigate the spin-wave excitations (magnons) in ferromagnetic manganese perovskites. In spite of the large differences in the Curie temperatures ($T_C$s) of different manganites, their low-temperature spin waves were found to have very similar dispersions with the zone boundary magnon softening. From

Priya Mahadevan, I. V. Solovyev, K. Terakura

The low-temperature spin dynamics of doped manganites have been analyzed within a tight-binding model, the parameters of which are estimated by mapping the results of ab initio density functional calculations onto the model. This approach is found to provide a good description of the spin dynamics of the doped manganites, observed earlier within the ab initi

R. Klimpel, S. Dietrich

The two-point correlation function in thin films is studied near the critical point of the corresponding bulk system. Based on fieldtheoretic renormalization group theory the dependences of this correlation function on the lateral momentum, the two distances normal to the free surfaces, temperature, and film thickness are determined. The corresponding scatte

A. M. Lacasta, I. R. Cantalapiedra, C. E. Auguet, A. Penaranda

A diffusion-reaction model for the growth of bacterial colonies is presented. The often observed cooperative behavior developed by bacteria which increases their motility in adverse growth conditions is here introduced as a nonlinear diffusion term. The presence of this mechanism depends on a response which can present hysteresis. By changing only the concen

Alexei Vazquez, Oscar Sotolongo-Costa

The dynamics of critical slope self-organized critical models is studied, using a previous mapping into a linear interface depinning model dragged at one end. The model is solved obtaining the complete set of scaling exponents. Some results are supported by previous RG developed for constant force linear interface depinning models but others, like the linear

J. A. Porto, F. J. Garcia-Vidal, J. B. Pendry

In this paper we show how transmission metallic gratings with very narrow and deep enough slits can exhibit transmission resonances for wavelengths larger than the period of the grating. By using a transfer matrix formalism and a quasi-analytical model based on a modal expansion, we show that there are two possible ways of transferring light from the upper s

Franz J. Wegner

S.C. Zhang has put forward the idea that high-temperature-superconductors can be described in the framework of an SO(5)-symmetric theory in which the three components of the antiferromagnetic order-parameter and the two components of the two-particle condensate form a five-component order-parameter with SO(5) symmetry. Interactions small in comparison to thi

C. Villagonzalo, R. A. Roemer, M. Schreiber

We study the thermoelectric transport properties in the three-dimensional Anderson model of localization near the metal-insulator transition [MIT]. In particular, we investigate the dependence of the thermoelectric power S, the thermal conductivity K, and the Lorenz number L_0 on temperature T. We first calculate the T dependence of the chemical potential fr

Yigal Meir

A simple non-interacting-electron model, combining local quantum tunneling and global classical percolation (due to a finite dephasing time at low temperatures), is introduced to describe a metal-insulator transition in two dimensions. It is shown that many features of the experiments, such as the exponential dependence of the resistance on temperature on th

V. A. Avetisov, A. H. Bikulov, S. V. Kozyrev

Methods of p-adic analysis are applied to the investigation of the spontaneous symmetry breaking in the models of spin glasses. A p-adic expression for the replica matrix is given and moreover the replica matrix in the models of spontaneous breaking of the replica symmetry in the simplest case is expressed in the form of the Vladimirov operator of p-adic fra

X. R. Wang, C. Y. Wong, X. C. Xie

We study the Anderson localization in a weakly coupled multilayer system with a strong magnetic field perpendicular to the layers. The phase diagram of 1/3 flux quanta per plaquette is obtained. The phase diagram shows that a three-dimensional quantum Hall effect phase exists for a weak on-site disorder. For intermediate disorder, the system has insulating a

Debabrata Biswas, Sudeshna Sinha

The zeroes of the Husimi function provide a minimal description of individual quantum eigenstates and their distribution is of considerable interest. We provide here a numerical study for pseudo- integrable billiards which suggests that the zeroes tend to diffuse over phase space in a manner reminiscent of chaotic systems but nevertheless contain a subtle si

S. Ciliberto, C. Laroche

The influence of the boundary layer properties on the heat transport in turbulent thermal convection is experimentally investigated in a cell with a rough bottom plate.It is shown that the standard 2/7 exponent of the convective heat flow dependence on the Rayleigh number, usually observed in cell with smooth boundaries, increases if the roughness has power

Jeffrey A. Willick

The implications of the massive, X-ray selected cluster of galaxies MS1054--03 at $z=0.83$ are discussed in light of the hypothesis that the primordial density fluctuations may be nongaussian. We generalize the Press-Schechter (PS) formalism to the nongaussian case, and calculate the likelihood that a cluster as massive as MS1054 would appear in the EMSS. Th

Carl H. Gibson, Rudolph E. Schild

Sir James Jeans&#39;s (1902 and 1929) linear, acoustic, theory of gravitational instability gives vast errors for the structure formation of the early universe. Gibson&#39;s (1996) nonlinear theory shows that nonacoustic density extrema produced by turbulence are gravitationally unstable at turbulent, viscous, or diffusive Schwarz scales L_ST, L_SV, L_SD, in

Carl H. Gibson

Jeans&#39;s (1902 & 1929) linear gravitational instability criterion gives truly spectacular errors in its predictions of cosmological structure formation according to Gibson&#39;s (1996) new nonlinear theory. Scales are determined by viscous or turbulent forces, or by diffusivity, at Schwarz length scales L_SV, L_ST, or L_SD, respectively, whichever is larg

M. G. Abadi, R. G. Bower, J. F. Navarro

We describe similarity solutions that characterize the collapse of collisional gas onto scalefree perturbations in an Einstein-de Sitter universe. We consider the effects of radiative cooling and derive self-similar solutions under the assumption that the cooling function is a power law of density and temperature, $Λ(T,ρ) \propto ρ^{3/2} T$. We use these res

Mikhail V. Medvedev, Abraham Loeb

We show that the relativistic two-stream instability can naturally generate strong magnetic fields with 1e-5 - 1e-1 of the equipartition energy density, in the collisionless shocks of Gamma-Ray-Burst (GRB) sources. The generated fields are parallel to the shock front and fluctuate on the very short scale of the plasma skin depth. The synchrotron radiation em

G. A. Tammann, A. Sandage, B. Reindl

Six different distance determination methods of Virgo cluster members yield a mean distance modulus of (m-M)^0(Virgo) = 31.60 +/- 0.09 (20.9 +/- 0.9 Mpc). This value can be carried out to > 10,000 km/s by means of 31 clusters whose distances are well known relative to the Virgo cluster. They yield H_0 = 56 +/- 4 (random error) +/- 6 (systematic error), indep

Mattias Christensson, Mark Hindmarsh

There is a reformulation of magnetohydrodynamics in which the fundamental dynamical quantities are the positions and velocities of the lines of magnetic flux in the plasma, which turn out to obey equations of motion very much like ideal strings. We use this approach to study the evolution of a primordial magnetic field generated during the radiation-dominate

M. S. Strickman, A. K. Harding, O. C. deJager

We have detected pulsed emission from the Vela pulsar at 2 - 30 keV during a 93 ks observation with the Rossi X-Ray Timing Explorer (RXTE). The RXTE pulse profile shows two peaks, that are roughly in phase with the EGRET peaks, but does not show any significant interpeak emission. The phase of Peak 2 is energy dependent, moving to higher phase with increasin

G. Efstathiou

We analyse the constraints that can be placed on a cosmological constant or quintessence-like component by combining observations of Type Ia supernovae with measurements of anisotropies in the cosmic microwave background. We use the recent supernovae sample of Perlmutter et al and observations of the CMB anisotropies to constraint the equation of state (w_Q

G. E. Romero, P. Benaglia, Diego F. Torres

We present a study on the possible association of unidentified $γ$-ray sources in the Third EGRET (3EG) catalog with different types of galactic objects such as Wolf-Rayet and Of stars, supernova remnants (SNRs), and OB associations (considered as pulsar tracers). We have made use of numerical simulations of galactic populations of $γ$-ray point sources in o

D. Reynaud, D. Downes

We present 13CO(1-0) and 12CO(2-1) aperture synthesis maps of the barred spiral galaxy NGC1530. The angular resolutions are respectively 3&#39;&#39;.1 and 1&#39;&#39;.6. Both transitions show features similar to the 12CO(1-0) map, with a nuclear feature (a ring or unresolved spiral arms) surrounded by two curved arcs. The average line ratios are 12CO(1-0)/13

Norman R. Trams, Jacco Th. van Loon, L. B. F. M. Waters, Albert A. Zijlstra

We present ISO photometric and spectroscopic observations of a sample of 57 bright Asymptotic Giant Branch stars and red supergiants in the Large Magellanic Cloud, selected on the basis of IRAS colours indicative of high mass-loss rates. PHOT-P and PHOT-C photometry at 12, 25 and 60 $μ$m and CAM photometry at 12 $μ$m are used in combination with quasi-simult

Erik Kuulkers, Rudy Wijnands, Michiel van der Klis

It is known that the overall (mean) intensity of the low-mass X-ray binary Cyg X-2 varies on time scales from a day to months, independently from the variations on time scales of hours to a day by which the source moves between the horizontal, normal and flaring branches. We present RXTE PCA observations of Cyg X-2, taken when its overall intensity was near

Kenji Tomita, Hideki Asada, Takashi Hamana

Distances play important roles in cosmological observations, especially in gravitational lens systems, but there is a problem in determining distances because they are defined in terms of light propagation, which is influenced gravitationally by the inhomogeneities in the universe. In this paper we first give the basic optical relations and the definitions o

Kenji Tomita, Premana Premadi, Takahiro T. Nakamura

Gravitational lensing of distant objects caused by gravitational tidal forces from inhomogeneities in the universe is weak in most cases, but it is noticed that it gives a great deal of information about the universe, especially regarding the distribution of dark matter. The statistical values of optical quantities such as convergence, amplification and shea

A. P. Reynolds, A. Owens, L. Kaper, A. N. Parmar

A 0.5-200 keV BeppoSAX spectrum of the non-pulsating high-mass X-ray binary 4U1700-37 is presented. The spectrum is well characterized by the standard accreting pulsar model of an absorbed power-law with a photon index of 1.07 +0.02 -0.03, sharply modified by an exponential cutoff above 5.9 +/- 0.2 keV. The e-folding energy of the cutoff is 23.9 +/-0.5 keV.

Tom Broadhurst, Andrew H. Jaffe

The large-scale maximum at k~0.05 identified in the power-spectrum of galaxy fluctuations provides a co-moving scale for measuring cosmological curvature. In shallow 3D surveys the peak is broad, but appears to be well resolved in 1D, at ~130 Mpc (k=0.048), comprising evenly spaced peaks and troughs. Surprisingly similar behaviour is evident at z=3 in the di

Esteban A. Calzetta, Alejandra Kandus

We study the corrections to the conformal evolution of primordial magnetic fields after recombination, produced by the fall of the ionized fraction of matter into the dark matter gravitational wells. This effect enhances the field around the protostructures being formed, and might help to understand the fields observed in galaxy clusters and hydrogen clouds.

J. B. Kogut, C. G. Strouthos

The three-dimensional four-fermion model with a Z_2 chiral symmetry and N=4 fermion species in the system is investigated numerically at non-zero temparature and chemical potential. The phase diagram in the (chemical potential, temperature) plane is mapped out quantitatively. A detailed finite size scaling analysis shows that the zero temperature and non-zer

Shaaban Khalil, Qaisar Shafi

For varying values of $\tanβ$, we study the effect of CP violating phases from the soft supersymmetry breaking terms in string-inspired models on the relic abundance and detection rates of the lightest neutralino (LSP). We find that the phases have no significant effect on the LSP relic abundance but can have a substantial impact on the detection rates.

D. P. Rideout, R. D. Sorkin

Starting from certain causality conditions and a discrete form of general covariance, we derive a very general family of classically stochastic, sequential growth dynamics for causal sets. The resulting theories provide a relatively accessible ``half way house&#39;&#39; to full quantum gravity that possibly contains the latter&#39;s classical limit (general

B. Basu-Mallick, H. Ujino, M. Wadati

By using the fact that Polychronakos-like models can be obtained through the `freezing limit&#39; of related spin Calogero models, we calculate the exact spectrum as well as partition function of SU(m|n) supersymmetric Polychronakos (SP) model. It turns out that, similar to the non-supersymmetric case, the spectrum of SU(m|n) SP model is also equally spaced.

Z. Ye, E. Hoskinson, H. Hsu

Here we show a complete band gap in acoustic propagation in water with regularly placed air-cylinders. Also for the first time, we report that in the gap, all cylinders oscillate in phase but exactly out of the phase of a wave source located inside the cylinder array.

A. N. Leznov

An explicit form of the generators of quantum and ordinary semisimple algebras for an arbitrary finite-dimensional representation is found. The generators corresponding to the simple roots are obtained in terms of a solution of a system of matrix equations. The result is presented in the form of $N_l\times N_l$ matrices, where $N_l$ is the dimension of the c

Ka-Luen Cheung, Man-Chun Leung

We study asymptotic behavior of positive smooth solutions of the conformal scalar curvature equation in ${\bf R}^n$. We consider the case when the scalar curvature of the conformal metric is bounded between two positive numbers outside a compact set. It is shown that the solution has slow decay if the radial change is controlled. For a positive solution with

Albert Schwarz

Let us consider a Lie (super)algebra $G$ spanned by $T_α$ where $T_α$ are quantum observables in BV-formalism. It is proved that for every tensor $c^{α_1...α_k}$ that determines a homology class of the Lie algebra $G$ the expression $c^{α_1...α_k}T_{α_1}...T_{α_k}$ is again a quantum observables. This theorem is used to construct quantum observables in BV si

G. X. Peng, H. C. Chiang, P. Z. Ning, B. S. Zou

The electric charge of strange quark matter is of vital importance to experiments. A recent investigation shows that strangelets are most likely highly negatively charged, rather than slightly positively charged as previously believed. Our present study indicates that negative charges can indeed lower the critical density, and thus be favorable to the experi

Marek Gazdzicki, Christina Markert

We argue that the measurement of open charm gives a unique opportunity to test the validity of pQCD-based and statistical models of nucleus-nucleus collisions at high energies. We show that various approaches used to estimate D-meson multiplicity in central Pb+Pb collisions at 158 A GeV give predictions which differ by more than a factor of 100. Finally we d

Julia A. Thompson

Preliminary values for the K+ -> pi+ mu+ mu- branching ratio and form factor are reported, based on 400 events, a factor of 2 more in total events and 100 times the present world sample of fully reconstructed events. The results are consistent with previous results on the pi+ e+ e- mode. However, the relatively large slope of the form factor in q^2, lambda =

H. Yoshizawa, T. Kakeshita, R. Kajimoto, T. Tanabe

Stripe order in La{2-x}Sr{x}NiO4 beyond x = 1/3 was studied with neutron scattering technique. At low temperatures, all the samples exhibit hole stripe order. Incommensurability εof the stripe order is approximately linear in the hole concentration n_h = x + 2δup to x = 1/2, where δdenotes the off-stoichiometry of oxygen atoms. The charge and spin ordering t

Liu Yaowen, Ping Huican, Zhao Hong, Wang Yinghai

A novel perturbation method for the stabilization of unstable intermediate states of hysteresis loop (i.e. S-shaped curve) is proposed. This method only needs output signals of the system to construct the perturbation form without delay-coordinate embedding technique, it is more practical for real-world systems. Stabilizing and tracking the unstable intermed

Liu Yaowen, Li Haibin, Zhao Hong, Wang Yinghai

Using the Poincaré section technique, we study in detail the dynamical behaviors of delay differential system and find a new type of solutions $S_i$ in short-time delay feedback. Our numerical results remind us to deny the opinion that there are no complex phenomena in short-time delay case. Many similarities between foundamental solution and the new type of

R. Tripp, D. Branch

In this paper, we make a comprehensive determination of the Hubble constant $H_0$ by using two parameters - the B-V color and the rate of decline $Δm_{15}$ - to simultaneously standardize the luminosities of all nearby Cepheid-calibrated type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a

William Stoeger, Marcelo Araujo, Tim Gebbie

Assuming that the cosmological principle holds, Maartens, Ellis and Stoeger (MES) recently constructed a detailed scheme linking anisotropies in the cosmic background radiation (CMB) with anisotropies and inhomogeneities in the large scale structure of the universe and showed how to place limits on those anisotropies and inhomogeneities simply by using CMB q

Lennox L. Cowie, Antoinette Songaila, Amy J. Barger

We have utilized various magnitude-limited samples drawn from an extremely deep and highly complete spectroscopic redshift survey of galaxies observed in seven colors in the Hawaii Survey Fields and the Hubble Deep Field to investigate the evolution of the universal rest-frame ultraviolet luminosity density from z = 1 to the present. The multi-color data (U&

Janet E. Cahn

This paper links prosody to the information in a text and how it is processed by the speaker. It describes the operation and output of LOQ, a text-to-speech implementation that includes a model of limited attention and working memory. Attentional limitations are key. Varying the attentional parameter in the simulations varies in turn what counts as given and

P. Maragakis, E. Cormier, P. Lambropoulos

We study the dynamics of the Potassium atom in the mid-infrared, high intensity, short laser pulse regime. We ascertain numerical convergence by comparing the results obtained by the direct expansion of the time-dependent Schroedinger equation onto B-Splines, to those obtained by the eigenbasis expansion method. We present ionization curves in the 12-, 13-,

Juhi-Lian Julian Ting

Rate equations are used to model spectroscopic observation of incoherent energy transfer in light-harvesting antenna systems based upon known structures. A two-parameter two-dimensional model is proposed. The transfer rates obtained, by matching the fluorescent decay, are self-consistent within our model.

Klaus Schenk, Barbara Drossel, Siegfried Clar, Franz Schwabl

We study finite-size effects in the self-organized critical forest-fire model by numerically evaluating the tree density and the fire size distribution. The results show that this model does not display the finite-size scaling seen in conventional critical systems. Rather, the system is composed of relatively homogeneous patches of different tree densities,

Ulrich Bunke, Martin Olbrich

We develop a geometric scattering theory for a geometrically finite group acting on (a vector bundle over) a symmetric space of negative curvature. In particular, we obtain the meromorphic continuation of Eisenstein series and scattering matrices and their functional equations.

D. G. Cerdeno, C. Munoz

We study the phenomenology of the strong-coupling limit of $E_8\times E_8$ heterotic string obtained from M-theory, using a Calabi-Yau compactification. After summarizing the standard embedding results, we concentrate on non-standard embedding vacua as well as vacua where non-perturbative objects as five-branes are present. We analyze in detail the different

Adrian R. Lugo

We obtain local parametrizations of classical non-compact Lie groups where adjoint invariants under maximal compact subgroups are manifest. Extension to non compact subgroups is straightforward. As a by-product parametrizations of the same type are obtained for compact groups. They are of physical interest in any theory gauge invariant under the adjoint acti

P. Facchi, S. Pascazio

The usual, &#34;static&#34; version of the quantum Zeno effect consists in the hindrance of the evolution of a quantum systems due to repeated measurements. There is however a &#34;dynamic&#34; version of the same phenomenon, first discussed by von Neumann in 1932 and subsequently explored by Aharonov and Anandan, in which a system is forced to follow a give

A. F. Medvedev, M. L. Schinkeev

Methods to detect the spectral sensitivity of an object using undulator radiation without monochromators or any other spectral devices are developed. The spectral transmission function of the object is calculated from its response to the spectrum-integral undulator radiation with the known spectral distribution. This response is measured as a function of the

Frank Sottile

Boris Shapiro and Michael Shapiro have a conjecture concerning the Schubert calculus and real enumerative geometry and which would give infinitely many families of zero-dimensional systems of real polynomials (including families of overdetermined systems)--all of whose solutions are real. It has connections to the pole placement problem in linear systems the

M. A. Jafarizadeh, S. K. Moayedi

The quantum mechanics of a spin 1/2 particle on a locally spatial constant curvature part of a (2+1)- spacetime in the presence of a constant magnetic field of a magnetic monopole has been investigated. It has been shown that these 2-dimensional Hamiltonians have the degeneracy group of SL(2,c), and para-supersymmetry of arbitrary order or shape invariance.

M. Trigiante

An intense study of the relationship between certain quantum theories of gravity realized on curved backgrounds and suitable gauge theories, has been originated by a remarkable conjecture put forward by Maldacena almost one year ago. Among the possible curved vacua of superstring or M-theory, spaces having the form of an Anti-de Sitter space-time times a com

Adrian R. Lugo

We present the explicit global realization of the isometries of anti-de Sitter like spaces of signature $(d_-,d_+)$, and their algebras in the space of functions on the pseudo-Riemannian symmetric space $SO(d_- +1,d_+) / SO(d_-,d_+)$. The process of going to the invariant boundaries leads to the realization of the corresponding conformal groups and algebras.

M. A. Jafarizadeh, H. Fakhri, S. K. Moayedi

Some special solutions of the Einstein-Maxwell action with a non-negative cosmological constant and a very heavy point mass particle have been obtained. The solutions correspond to static spacetime of locally constant curvature in its spatial part and a constant magnetic field of a magnetic monopole together with deficit of angle at the location of point mas