January 2001 arXiv papers — page 5

R. S. Willey

We find that if the Higgs mass is close to its present experimental lower limit (100 GeV),Yukawa interactions in the quark-Higgs sector can make substantial contributions to the heavy quark MS masses.

Kazumi Okuyama

We consider an open Wilson line as a momentum representation of a boundary state which describes a D-brane in a constant B-field background. Using this picture, we study the Seiberg-Witten map which relates the commutative and noncommutative gauge fields, and determine the products of fields appearing in the general terms in the expansion of this map.

V. E. Bunakov, I. B. Ivanov

The problem of existence and constructing of integrals of motion in stationary quantum mechanics and its connection with quantum chaoticity is discussed. It is shown that the earlier suggested quantum chaoticity criterion characterizes destruction of initial symmetry of regular system and of basis quantum numbers under influence of perturbation. The converge

John Watrous

In this paper we give a polynomial-time quantum algorithm for computing orders of solvable groups. Several other problems, such as testing membership in solvable groups, testing equality of subgroups in a given solvable group, and testing normality of a subgroup in a given solvable group, reduce to computing orders of solvable groups and therefore admit poly

Andres Aguado

We present ab initio perturbed ion calculations on the structures and relative stabilities of doubly charged [(NaCl)_m(Na)_2]2+ cluster ions. The obtained stabilities show excellent agreement with experimental abundances obtained from mass spectra. Those enhanced stabilities are found to be a consequence of highly compact structures that can be built only fo

Tomislav Ivezic

In this paper we present an invariant formulation of special relativity, i.e., the ''true transformations relativity.'' It deals either with true tensor quantities (when no basis has been introduced) or equivalently with coordinate- based geometric quantities comprising both components and a basis (when some basis has been introduced). It is

V. Balandin, H. Mais

Some limit theorems are proven for the linear oscillator with random coefficients. The asymptotic behaviour of the moments is studied in detail. The technique presented in this paper can be applied to general linear systems with noise and is well suited for the investigation of stochastic beam dynamics in accelerators.

L. I. Urutskoev, V. I. Liksonov, V. G. Tsinoev

Results of experimental studies of electric explosion, in water, of foils made of extremely pure materials are presented. New chemical elements detected both by spectroscopic measurements during the electric discharge and by a mass-spectrometer analysis of sediments after the discharge have been found to appear. A "strange" radiation associated with

A. Chernomoretz, M. Ison, S. Ortiz, C. O. Dorso

We study, using molecular dynamics techniques, how boundary conditions affect the process of fragmentation of finite, highly excited, Lennard-Jones systems. We analyze the behavior of the caloric curves (CC), the associated thermal response functions (TRF) and cluster mass distributions for constrained and unconstrained hot drops. It is shown that the result

Ben-Hao Sa, Amand Faessle, C. Fuchs, An Tai

Using a hadron-string cascade model LUCIAE, the $ϕ$ meson production in heavy ion collisions (Pb+Pb) and elementary collisions (p+p) were studied systematically. Within the framework of the model, the experimentally measured $ϕ$ enhancement in Pb+Pb over p+p collisions can be mostly explained by the collective effects in the gluon string emission and the red

K. Yu. Kazakov, D. V. Shulga

The cross section asymmetry $Σ$ in deuteron disintegration with linearly polarized light is considered in the framework of the Bethe-Salpeter formalism. Relativistic contributions to the asymmetry are investigated within the approximation, which takes into account the one-body part of the electromagnetic current operator and the dominant positive-energy part

L. Kaplan

We study wave function structure for quantum graphs in the chaotic and disordered regime, using measures such as the wave function intensity distribution and the inverse participation ratio. The result is much less ergodicity than expected from random matrix theory, even though the spectral statistics are in agreement with random matrix predictions. Instead,

R. B. Alexeev, V. V. Peller

We continue studying the problem of analytic approximation of matrix functions. We introduce the notion of a partial canonical factorization of a badly approximable matrix function $Φ$ and the notion of a canonical factorization of a very badly approximable matrix function $Φ$. Such factorizations are defined in terms of so-called balanced unitary-valued fun

R. B. Alexeev, V. V. Peller

For an $n\times n$ bounded matrix function $Φ$ we study unitary interpolants $U$, i.e., unitary-valued functions $U$ such that $\hat U(j)=\hatΦ(j)$, $j<0$. We are looking for unitary interpolants $U$ for which the Toeplitz operator $T_U$ is Fredholm. We give a new approach based on superoptimal singular values and thematic factorizations. We describe Wiener-

Luc Menichi

Let $F\hookrightarrow E\twoheadrightarrow B$ be a fibration whose base space $B$ is a finite simply-connected CW-complex of dimension $\leq p$ and whose total space $E$ is a path-connected CW-complex of dimension $\leq p-1$. If $α\in H^{+}(F;\mathbb{F}_p)$ then $α^{p}=0$.

Mihail N. Kolountzakis, Michael Papadimitrakis

A conjecture of Fuglede states that a bounded measurable set D, of measure 1, can tile space by translations if and only if the Hilbert space L^2(D) has an orthonormal basis consisting of exponentials exp(i 2 pi lambda x). If D has the latter property it is called spectral. Let D be a polytope with the following property: there is a direction u such that, of

R. B. Alexeev, V. V. Peller

We study the problem of invariance of indices of thematic factorizations. Such factorizations were introduced in [PY1] for studying superoptimal approximation by bounded analytic matrix functions. As shown in [PY1], the indices may depend on the choice of a thematic factorization. We introduce the notion of a monotone thematic factorization. The main result

Keiji Oguiso, De-Qi Zhang

The aim of this note is to characterize a K3 surface of Klein-Mukai type in terms of its symmetry.

Roger Ellman

&#34;Goldbach&#39;s Conjecture&#34; proven by analysis of how all combinations of the odd primes, summed in pairs, generates all of the even numbers.

K. Graham, I. Runkel, G. M. T Watts

We consider perturbations of unitary minimal models by boundary fields. Initially we consider the models in the limit as c -> 1 and find that the relevant boundary fields all have simple interpretations in this limit. This interpretation allows us to conjecture the IR limits of flows in the unitary minimal models generated by the fields ϕ_{rr} of `low&#39; w

Motoi Tachibana

Motivated by a recently proposed &#34;bigravity&#34; model with two positive tension $AdS_4$ branes in $AdS_5$ by Kogan et al.[hep-th/0011141], we study behavior of bulk gauge field in the model. In this case, the zero mode of the gauge field is not constant but depends on the fifth dimensional coordinate transverse to the brane. The zero mode then becomes m

Jian Dai, Xing-Chang Song

Differential structure of lattices can be defined if the lattices are treated as models of noncommutative geometry. The detailed construction consists of specifying a generalized Dirac operator and a wedge product. Gauge potential and field strength tensor can be defined based on this differential structure. When an inner product is specified for differentia

Sh. Mamedov, Jian-Zu Zhang, V. Zhukovskii

The role of supercharge operators is studied in the case of a Dirac particle moving in a constant chromomagnetic field. The Hamiltonian is factorised and the ground state wave function in the case of unbroken supersymmetry is determined.

Andrey Yu. Dubin

I adapt the Gauge String, representing the strong coupling (SC) expansion in the continuous D>=3 Yang-Mills theory (YM_{D}) with a sufficiently large bare coupling constant λ>λ_{cr} and a fixed ultraviolet cut off Λ, to the analysis of the regularized Wilson&#39;s loop-averages. When generalized to describe the fat (rather than infinitely thin) flux-tubes, t

G. Delfino

We determine the form factor expansion of the one-point functions in integrable quantum field theory at finite temperature and find that it is simpler than previously conjectured. We show that no singularities are left in the final expression provided that the operator is local with respect to the particles and argue that the divergences arising in the non-l

S. A. Paston, E. V. Prokhvatilov, V. A. Franke

The counterterms, which must be included into Light-Front Hamiltonian of $QED_2$ to get the equivalence with conventional Lorentz-covariant formulation, are found. This is done to all orders of perturbation theory in fermion mass, using the bosonization at intermediate steps and comparing Light-Front and Lorentz-covariant perturbation theories for bosonized

D. Ebert, R. N. Faustov, V. O. Galkin

Exclusive semileptonic B decays to radially excited charmed mesons and rare radiative B decay to the orbitally excited tensor K_2^*(1430) meson are investigated in the framework of the relativistic quark model based on the quasipotential approach in quantum field theory. The heavy quark expansion is applied for the semileptonic B\to D^{(*)}&#39;eνdecays. Bot

P. Schweitzer, D. Urbano, M. V. Polyakov, C. Weiss

We compute the quark and antiquark transversity distributions in the nucleon at a low normalization point of 600 MeV in the large-$N_c$ limit, where the nucleon can be described as a soliton of an effective chiral theory (chiral quark-soliton model). The flavor-nonsinglet distributions, $δu(x) - δd(x)$ and $δ\bar u(x) - δ\bar d(x)$, appear in leading order o

G. Passarino

The most celebrated aspects of precision physics are briefly summarized. New ideas are also introduced that may lead to further developments in the field of radiative corrections, with special emphasis to multi-loop numerical evaluation and to a correct treatment of QED radiation for arbitrary processes.

M. Blazek

In one-dimensional case the search for presence of the anomalous phenomena in multiplicity distributions is usually performed in frame of the horizontal, vertical and mixed types of the analysis. We show that if the data involve a d-dimensional phase space, there exists a convenient procedure, generalizing the one-dimensional approach, which allows to introd

Santi Bejar, Jaume Guasch, Joan Sola

Flavor Changing Neutral Current decays of the top quark within the strict context of the Standard Model are known to be extremely rare. In fact, they are hopelessly undetectable at the Tevatron, LHC and LC in any of their scheduled upgradings. Therefore, if a few of these events eventually show up in the future we will have certainly discovered new physics.

G. Dillon, G. Morpurgo

We derive,using the general QCD parametrization,the approximate relation r^{2}(π^{+}) - r^{2}(K^(+)) approximately equal to -r^{2}(K^(o), where the r&#39;s are the charge radii.The relation is satisfied but the experimental errors are still sizeable.The derivation is similar to (but even simpler than) that for r^{2}(p) -r^{2}(n) approximately equal to r^{2}(

Dariusz Prorok, Ludwik Turko

We calculate the velocity of sound in an ideal gas of massive hadrons with non-vanishing baryon number. The gas is in thermal and chemical equilibrium. Also we show that the temperature dependence $T(τ) \cong T_{0} \cdot ({τ_{0} \over τ})^{c_{s}^{2}}$ is approximately valid, when the gas expands longitudinally according to the Bjorken law.

Andrzej Czarnecki, William J. Marciano

QED, Hadronic, and Electroweak Standard Model contributions to the muon anomalous magnetic moment, a_mu = (g_mu-2)/2, are reviewed. Theoretical uncertainties in the prediction a_mu^SM = 116591597(67) times 10^{-11} are scrutinized. Effects due to ``New Physics&#39;&#39; are described. Implications of the current experiment vs. theory constraint a_mu^exp - a_

Abel Camacho

In the present work the detection, by means of a nondemolition measurement, of a Yukawa term, coexisting simultaneously with gravity, has been considered. In other words, a nondemolition variable for the case of a particle immersed in a gravitational field containing a Yukawa term is obtained. Afterwards the continuous monitoring of this nondemolition parame

István Rácz

Smooth spacetimes with a compact Cauchy horizon ruled by closed null geodesics are considered. The compact Cauchy horizon is assumed to be non-degenerate. Then, supporting the validity of Penrose&#39;s strong cosmic censor hypothesis, the existence of a smooth Killing vector field in a neighbourhood of the horizon on the Cauchy development side is shown.

D. V. Gal&#39;tsov, V. V. Dyadichev

Born-Infeld generalization of the Yang-Mills action suggested by the superstring theory gives rise to modification of previously known as well as to some new classical soliton solutions. Earlier it was shown that within the model with the usual trace over the group generators classical glueballs exist which form an infinite sequence similar to the Bartnik-Mc

D. V. Gal&#39;tsov

Classical singularities inside black holes in the Einstein-Yang-Mills theory exhibit unusual features. Only for discrete values of the black hole mass one encounters singularities of the Schwarzschild type (timelike) and the Reissner-Nordstrom type (spacelike). For a generic mass the approach to singularity is not smooth: the metric oscillates with an infini

Marcus Hutter

Solomonoff sequence prediction is a scheme to predict digits of binary strings without knowing the underlying probability distribution. We call a prediction scheme informed when it knows the true probability distribution of the sequence. Several new relations between universal Solomonoff sequence prediction and informed prediction and general probabilistic p

Ming-Yang Kao

An evolutionary tree is a rooted tree where each internal vertex has at least two children and where the leaves are labeled with distinct symbols representing species. Evolutionary trees are useful for modeling the evolutionary history of species. An agreement subtree of two evolutionary trees is an evolutionary tree which is also a topological subtree of th

Paul M. Aoki, Amy Hurst, Allison Woodruff

We describe tap tips, a technique for providing touch-screen target location hints. Tap tips are lightweight in that they are non-modal, appear only when needed, require a minimal number of user gestures, and do not add to the standard touchscreen gesture vocabulary. We discuss our implementation of tap tips in an electronic guidebook system and some usabili

Ming-Yang Kao, Yuan Ma, Michael Sipser, Yiqun Yin

We study on-line strategies for solving problems with hybrid algorithms. There is a problem Q and w basic algorithms for solving Q. For some lambda <= w, we have a computer with lambda disjoint memory areas, each of which can be used to run a basic algorithm and store its intermediate results. In the worst case, only one basic algorithm can solve Q in finite

Simeon Warner

I outline the involvement of the Los Alamos e-print archive (arXiv) within the Open Archives Initiative (OAI) and describe the implementation of the data provider side of the OAI protocol v1.0. I highlight the ways in which we map the existing structure of arXiv onto elements of the protocol.

Philip W. Anderson

A number of authors have taken issue with the demonstration that the 2D Fermion gas with short-range repulsive interactions (and, of course, including spin) cannot be consistently treated as a renormalised quasiparticle system. This paper shows that the arguments given in some of these papers are invalid or irrelevant.

W. Pan, H. L. Stormer, D. C. Tsui, L. N. Pfeiffer

At very large tilt of the magnetic (B) field with respect to the plane of a two-dimensional electron system the transport in the integer quantum Hall regime at $ν$ = 4, 6, and 8 becomes strongly anisotropic. At these filling factors the usual {\em deep minima} in the magneto-resistance occur for the current flowing {\em perpendicular} to the in-plane B field

S. Aubry, G. Kopidakis, A. M. Morgante, G. P. Tsironis

It is well known that any amount of energy injected in a harmonic oscillator which is resonant and weakly coupled with a second harmonic oscillator, tunnels back and forth between these two oscillators. When the two oscillators are anharmonic, the amplitude dependence of their frequencies breaks, in general, any initial resonance so that no substantial energ

G. Biotteau, M. Hennion, F. Moussa, L. Pinsard

We describe the evolution of the static and dynamic spin correlations of La$_{1-x}$Ca$_x$MnO$_3$, for x=0.1, 0.125 and 0.2, where the system evolves from the canted magnetic state towards the insulating ferromagnetic state, approaching the metallic transition (x=0.22). In the x=0.1 sample, the observation of two spin wave branches typical of two distinct typ

Ulrich K. Roessler

A cluster Monte Carlo method for systems of classical spins with purely dipolar couplings is presented. It is tested and applied for finite arrays of perpendicular Ising dipoles on the triangular lattice. This model is a modification with long-range interactions of the geometrically frustrated Ising antiferromagnet. From measurements of integrated autocorrel

Z. Y. Weng, D. N. Sheng, C. S. Ting

In the presence of nonlocal phase shift effects, a quasiparticle can remain topologically stable even in a spin-charge separation state due to the confinement effect introduced by the phase shifts at finite doping. True deconfinement only happens in the zero-doping limit where a bare hole can lose its integrity and decay into holon and spinon elementary exci

Barbara Drossel

This review is an introduction to theoretical models and mathematical calculations for biological evolution, aimed at physicists. The methods in the field are naturally very similar to those used in statistical physics, although the majority of publications appeared in biology journals. The review has three parts, which can be read independently. The first p

J. Kopu, E. V. Thuneberg

We have studied theoretically the flow of superfluid 3He-A in parallel-plate geometry. The equilibrium order-parameter texture is calculated numerically in two spatial dimensions consisting of the coordinates along the flow direction and perpendicular to the plates. The calculations have been done using the hydrostatic theory in the Ginzburg-Landau region an

J. Dzubiella, H. M. Harreis, C. N. Likos, H. Lowen

We examine sedimentation density profiles of star polymer solutions as an example of colloidal systems in sedimentation equilibrium which exhibit reentrant melting in their bulk phase diagram. Phase transitions between a fluid and a fluid with an intercalated solid are observed below a critical gravitational strength $α^{*}$. Characteristics of the two fluid

K. Capelle, M. A. L. Marques, E. K. U. Gross

The relativistic generalization of the theory of superconductivity is reviewed with respect to its conceptual basis and first applications. The construction of relativistically covariant order parameters for superconductors is outlined and the generalization of the Dirac equation for the superconducting state is presented. A weakly relativistic expansion of

Dave Allen, Patrick Azaria, Philippe Lecheminant

The quantum ANNNI chain in a transverse field is investigated by means of the bosonization approach in the limit of large next-nearest neighbor interaction. In this regime, this model can be viewed as a weakly coupled two-leg zigzag ladder which enables us to derive its low energy effective field theory. In particular, it is shown that the effect of frustrat

Julien Barre, Thierry Dauxois, Stefano Ruffo

A striking clustering phenomenon in the antiferromagnetic Hamiltonian Mean-Field model has been previously reported. The numerically observed bicluster formation and stabilization is here fully explained by a non linear analysis of the Vlasov equation.

N. Shibata, D. Yoshioka

The ground state phase diagram of 2D electrons in a high Landau level (index N=2) is studied by the density matrix renormalization group method. Pair correlation functions are systematically calculated for various filling factors from v=1/8 to 1/2. It is shown that the ground state phase diagram consists of three different CDW states called stripe-phase, bub

Kyungsik Kim, B. O. Shim, Y. S. Kong, B. I. Henry

We investigate chaotic and multi-fractal properties of a two parameter map of the unit interval onto itself -- the Kim-Kong map. These results are compared with similar properties in well known one parameter maps of the unit interval onto itself.

Gennady Y. Chitov, Andrew J. Millis

We calculate the basic parameters of the Fermi Liquid: the scattering vertex, the Landau interaction function, the effective mass, and physical susceptibilities for a model of two-dimensional (2D) fermions with a short ranged interaction at non-zero temperature. The leading temperature dependences of the spin components of the scattering vertex, the Landau f

J. Kaupuzs

We have tested the theoretical values of critical exponents, predicted for the three--dimensional Heisenberg model, based on the published Monte Carlo (MC) simulation data for the susceptibility. Two different sets of the critical exponents have been considered - one provided by the usual (perturbative) renormalization group (RG) theory, and another predicte

K. Goral, M. Gajda, K. Rzazewski

We analyze the coherent multi-mode dynamics of a system of coupled atomic and molecular Bose gases. Starting from an atomic Bose-Einstein condensate with a small thermal component, we observe a complete depletion of the atomic and molecular condensate modes on a short time scale due to significant population of excited states. Giant coherent oscillations bet

A. Saiz, R. Dominguez-Tenreiro, P. B. Tissera, S. Courteau

We analyze the structural and dynamical properties of disk-like objects formed in fully consistent cosmological simulations which include inefficient star formation. Comparison with data of similar observable properties of spiral galaxies gives satisfactory agreement, in contrast with previous findings using other codes. This suggests that the stellar format

A. Saiz, R. Dominguez-Tenreiro, P. B. Tissera, S. Courteau

We analyze the structural and dynamical properties of disk-like objects formed in fully consistent cosmological simulations with an inefficient star formation algorithm. Comparison with data of similar observable properties of spiral galaxies gives satisfactory agreement.

Robert J. Nemiroff, Gabriela F. Marani, Jay P. Norris, Jerry T. Bonnell

A new search for the gravitational lens effects of a significant cosmological density of supermassive compact objects (SCOs) on gamma-ray bursts has yielded a null result. We inspected the timing data of 774 BATSE-triggered GRBs for evidence of millilensing: repeated peaks similar in light-curve shape and spectra. Our null detection leads us to conclude that

R. J. Reynolds, N. C. Sterling, L. M. Haffner, S. L. Tufte

The extremely faint, temperature sensitive ``auroral&#39;&#39; emission line [N II] 5755 has been detected from the low density ionized gas along the sight line toward l = 130.0, b = -7.5 using the Wisconsin H-Alpha Mapper (WHAM). The intensity of this emission line, relative to the red nebular line [N II] 6584, is found to be twice that observed in bright,

Karl E. Haisch, Elizabeth A. Lada, Charles J. Lada

We report the results of the first sensitive L-band (3.4 micron) imaging survey of the young IC 348 cluster in Perseus. In conjunction with previously acquired JHK (1.25, 1.65, 2.2 micron) observations, we use L-band data to obtain a census of the circumstellar disk population to m_K=m_L<=12.0 in the central 110 square arcmin region of the cluster. An analys

M. Zoccali, A. Renzini, S. Ortolani, A. Bragaglia

We present a new determination of the distance (and age) of the Galactic globular cluster 47 Tucanae (NGC 104) based on the fit of its white dwarf (WD) cooling sequence with the empirical fiducial sequence of local WD with known trigonometric parallax, following the method described in Renzini et al. (1996). Both the cluster and the local WDs were imaged wit

I. Agudo, J. L. Gomez, D. C. Gabuzda, J. C. Guirado

We present a new centimeter polarimetric VLBI image of the BL Lac object 0735+178. This source exhibits one of the most pronounced curvatures observed in jets of AGNs, with two sharp apparent bends of 90 degrees within the inner 2 milliarcseconds from the core. Through the analysis of the data gathered over the past decades we study whether this curvature is

P. M. Solomon

The extraordinary starbursts found in ultraluminous IR galaxies occur in molecular gas concentrated in compact very massive &#34;clouds&#34; which we call &#34;Extreme Starbursts&#34;. They have one thousand times the mass but are only a few times larger than GMCs. High-mass star formation in sufficiently dense and massive structures does not disrupt further

Piero Ullio, HongSheng Zhao, Marc Kamionkowski

The past growth of the central black hole (BH) might have enhanced the density of cold dark matter halo particles at the Galactic center. We compute this effect in realistic growth models of the present (2-3)*10**6 solar mass BH from a low-mass seed BH, with special attention to dynamical modeling in a realistic galaxy environment with merger and orbital dec

G. R. Meurer

Optical and HI imaging of both dwarf irregular (dI) and Blue Compact Dwarf (BCD) galaxies reveal important clues on how dwarf galaxies evolve and their star formation is regulated. Both usually show evidence for stellar and gaseous disks. However, their total mass is dominated by dark matter. Gas rich dwarfs form with a range of disk structural properties. T

G. R. Meurer, Mark Seibert

We review new and published results to examine how well the bolometric flux of starbursts can be recovered from ultraviolet (UV) and optical observations. We show that the effective absorption of starbursts can be substantial, up to \~10 mag in the far UV, and ~5 mag in H-alpha, but apparently not as high as some claims in the literature (several tens to a t

A. C. Fabian, C. S. Crawford, S. Ettori, J. S. Sanders

We present a Chandra observation of the powerful radio galaxy 3C294 showing clear evidence for a surrounding intracluster medium. At a redshift of 1.786 this is the most distant cluster of galaxies yet detected in X-rays. The radio core is detected as a point source, which has a spectrum consistent with a heavily-absorbed power law implying an intrinsic 2-10

F. L. Schoeier, H. Olofsson

Using a detailed radiative transfer analysis, combined with an energy balance equation for the gas, we have performed extensive modelling of circumstellar CO radio line emission from a large sample of optically bright carbon stars. We determine some of the basic parameters that characterize circumstellar envelopes (CSEs), e.g., the stellar mass loss rate, th

T. P. Roberts, N. J. Schurch, R. S. Warwick

We use ROSAT HRI spatial data and ASCA spectral measurements for a sample of seven nearby, early type spiral galaxies, to address the question of whether a low-luminosity Active Galactic Nucleus (LLAGN) is present in galaxies that have a LINER 2 classification. The brightest discrete X-ray source in the ROAST HRI observations is invariably found to be positi

A. R. Weiss, S. Hippler, M. E. Kasper, N. J. Wooder

We present first results of a simultaneous atmospheric turbulence measurement campaign at the Calar Alto (Spain) 1.23m and 3.5m telescopes. A SCIDAR instrument and the Calar Alto Adaptive Optics system ALFA were used at the 1.23m and 3.5m telescopes respectively to determine essential turbulence parameters like the Fried parameter r_0, the isoplanatic angle

W. A. Dziembowski, P. R. Goode, J. Schou

We have analyzed the full set of SOHO/MDI f- and p-mode oscillation frequencies from 1996 to date in a search for evidence of solar radius evolution during the rising phase of the current activity cycle. Like Antia et al. (2000), we find that a significant fraction of the f-mode frequency changes scale with frequency; and that if these are interpreted in ter

R. Sadat, B. Guiderdoni, J Silk

We study the evolution of stellar content and the chemical enrichment of the universe averaged over the whole population of galaxies by means of a series of chemo-spectrophotometric models that take into account the metallicity and dust obscuration effects. We investigate various classes of cosmic star formation rates (CSFR) histories consistent with current

P. Tenjes, J. Einasto, H. M. Maitzen, H. Zinnecker

Using the recently determined spatial velocity components of the extreme runaway star HIP 60350 and a gravitation potential model of the Galaxy, we integrate the orbit of HIP 60350 back to the plane of the Galaxy. In this way, a possible location of the formation of the star is determined. We estimate the uncertainty of the result due to the uncertainties of

R. Arlt, G. Rudiger

We perform global three-dimensional simulations of accretion disks integrating the compressible, non-viscous, but diffusive MHD equations. The disk is supposed to be isothermal. We make use of the ZEUS-3D code integrating the MHD equations and added magnetic diffusivity. We measure the efficiency of the angular-momentum transport. Various model simulations d

Takayoshi Nakamura, Hideyuki Umeda, Koichi Iwamoto, Ken&#39;ichi Nomoto

We examine the characteristics of nucleosynthesis in &#39;hypernovae&#39;, i.e., supernovae with very large explosion energies ($\gsim 10^{52}$ ergs). Implications for the cosmic chemical evolution and the abundances in M82 are discussed.

Pieter G. van Dokkum, Marijn Franx

Morphological and spectroscopic studies of high redshift clusters indicate that a significant fraction of present-day early-type galaxies was transformed from star forming galaxies at z<1. On the other hand, the slow luminosity evolution of early-type galaxies and the low scatter in their color-magnitude relation indicate a high formation redshift of their s

Greg L. Bryan, G. Mark Voit

We use simulations to predict the X-ray surface brightness distribution arising from hot, cosmologically distributed diffuse gas. The distribution is computed for two bands: 0.5-2 keV and 0.1-0.4 keV, using a cosmological-constant dominated cosmology that fits many other observations. We examine a number of numerical issues such as resolution, simulation vol

G. Mark Voit, Greg L. Bryan

Hot intergalactic gas in clusters, groups, and filaments emanates a continuous background of 0.5-2.0 keV X-rays that ought to be detectable with the new generation of X-ray observatories. Here we present selected results from a program to simulate the surface-brightness distribution of this background with an adaptive-mesh cosmological hydrodynamics code. We

M. C. Bento, O. Bertolami, R. Rosenfeld, L. Teodoro

Self-interacting dark matter has been suggested in order to overcome the difficulties of the Cold Dark Matter model on galactic scales. We argue that a scalar gauge singlet coupled to the Higgs boson, leading to an invisibly decaying Higgs, is an interesting candidate for this self-interacting dark matter particle.

M. B. Hecht, C. D. Roberts, S. M. Schmidt

Contributions to the neutron's EDM, are calculated using a well-constrained Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The momentum-dependent quark dressing amplifies the contribution from the current-quarks' EDMs; and dressed-quark confinement and binding make distinguishable the effect of the two CP and T violating interactions: i gam

Judith A. McGovern

We present calculations of differential cross sections for Compton scattering from the proton, using amplitudes calculated to fourth order in heavy baryon chiral perturbation theory. We compare with available data up to 200 MeV. We find that the agreement for angles below 90 degree is acceptable over the whole energy range, but that at more backward angles t

Ian I. Kogan, Alex Kovner, Bayram Tekin

We show that correlators of some local operators in gauge theories are sensitive to the presence of the instantons even at high temperature where the latter are bound into instanton-anti-instanton "molecules". We calculate correlation functions of such operators in the deconfined phase of the 2+1 dimensional Georgi-Glashow model and discuss analogous quantit

Jamal Sakhr, Niall D. Whelan

We extend the Gutzwiller trace formula to systems of noninteracting identical particles. The standard relation for isolated orbits does not apply since the energy of each particle is separately conserved causing the periodic orbits to occur in continuous families. The identical nature of the particles also introduces discrete permutational symmetries. We exp

Saurya Das, J. Gegenberg, V. Husain

We describe a class of asymptotically AdS scalar field spacetimes, and calculate the associated conserved charges for three, four and five spacetime dimensions using the conformal and counter-term prescriptions. The energy associated with the solutions in each case is proportional to $\sqrt{M^2 - k^2}$, where $M$ is a constant and $k$ is a scalar charge. In

B. Fak, N. H. van Dijk, A. S. Wills

Moreno and Sauls [Phys. Rev. B 63, 024419 (2000)] have recently tried to reanalyze earlier neutron scattering studies of the antiferromagnetic order in UPt3 with a magnetic field applied in the basal plane. In their calculation of the magnetic Bragg peak intensities, they perform an average over different magnetic structures belonging to distinct symmetry re

Alejandro Gangui, Levon Pogosian, Serge Winitzki

We propose a new method for a numerical computation of the angular bispectrum of the CMB anisotropies arising from active models such as cosmic topological defects, using a modified Boltzmann code based on CMBFAST. The method does not use CMB sky maps and requires moderate computational power. As a first implementation, we apply our method to a recently prop

J. C. Niemeyer, R. Parentani

We investigate the insensitivity of the predictions of inflationary models with respect to modifications of Planck energy physics. The modification we consider consists in replacing the usual dispersion relation by nonlinear ones. This way of addressing the problem has recently recieved attention and contradictory results were found. Our main result is to sh

Gergely Palla, Gabor Vattay, Andre Voros, Niels Sondergaard

We review studies of an evolution operator L for a discrete Langevin equation with a strongly hyperbolic classical dynamics and a Gaussian noise. The leading eigenvalue of L yields a physically measurable property of the dynamical system, the escape rate from the repeller. The spectrum of the evolution operator L in the weak noise limit can be computed in se

Vito Latora, Massimo Marchiori

We introduce the concept of efficiency of a network, measuring how efficiently it exchanges information. By using this simple measure small-world networks are seen as systems that are both globally and locally efficient. This allows to give a clear physical meaning to the concept of small-world, and also to perform a precise quantitative a nalysis of both we

F. Gastineau, R. nebauer, J. Aichelin

Employing an extended three flavor version of the NJL model we discuss in detail the phase diagram of quark matter. The presence of quark as well as of diquark condensates gives raise to a rich structure of the phase diagram. We study in detail the chiral phase transition and the color superconductivity as well as color flavor locking as a function of the te

John Herrick, Suckjoon Jun, John Bechhoefer, Aaron Bensimon

We formulate a kinetic model of DNA replication that quantitatively describes recent results on DNA replication in the in vitro system of Xenopus laevis prior to the mid-blastula transition. The model describes well a large amount of different data within a simple theoretical framework. This allows one, for the first time, to determine the parameters governi

Masahiro Takada

We propose a new method for extracting the non-Gaussian signatures on the isotemperature statistics in the cosmic microwave background (CMB) sky, which is induced by the gravitational lensing due to the intervening large-scale structure of the universe. To develop the method, we focus on a specific statistical property of the intrinsic Gaussian CMB field; a

Muneto Nitta

We reconsider the supersymmetric Wess-Zumino-Witten (SWZW) term in four dimensions. It has been known that the manifestly supersymmetric form of the SWZW term includes derivative terms on auxiliary fields, the highest components of chiral superfields, and then we cannot eliminate them by their equations of motion. We discuss a possibility for the elimination

Guo-Dong Li, Atsushi Ogawa, Yoshifumi Harada, Michael I. Tribelsky

The pattern selection problem in binary-mixture convection in an extended channel with a lateral through-flow is presented. The through-flow breaks left--right parity and changes pattern dynamics dramatically. The problem is studied based on computer simulation of the complete set of hydrodynamic equations (Oberbeck-Boussinesq approximation) in the two-dimen

The OPAL collaboration, G. Abbiendi

A sample of 3.73 million hadronic Z decays, recorded with the OPAL detector at LEP in the years 1991-95, has been used to search for a narrow resonance corresponding to the decay of the D*&#39;+/-(2629) meson into D*+/- pi+ pi-. The D*+ mesons are reconstructed in the decay channel D*+ -> D0 pi+ with D0 -> K- pi+. No evidence for a narrow D*&#39;+/-(2629) re