September 2001 arXiv papers — page 15

R. Alvarez, A. Jorissen, B. Plez, D. Gillet

This paper presents statistics of the line-doubling phenomenon in a sample of 81 long-period variable (LPV) stars of various periods, spectral types and brightness ranges. When correlated with a mask mimicking a K0III spectrum, 54% of the sample stars clearly showed a double-peaked cross-correlation profile around maximum light, reflecting double absorption

Myung Gyoon Lee, Hong Soo Park, Sang Chul Kim, William H. Waller

We present a photometric study of the stars in ionizing star clusters embedded in several giant HII regions of M33 (CC93, IC 142, NGC 595, MA2, NGC 604 and NGC 588). Our photometry are based on the HST-WFPC2 images of these clusters. Color-magnitude diagrams and color-color diagrams of these clusters are obtained and are used for estimating the reddenings an

Y. I. Izotov, F. H. Chaffee, C. B. Foltz, T. X. Thuan

Long-slit Keck II, 4m Kitt Peak, and 4.5m MMT spectrophotometric data are used to investigate the stellar population and the evolutionary status of I Zw 18C, the faint C component of the nearby blue compact dwarf galaxy I Zw 18. Hydrogen H$α$ and H$β$ emission lines are detected in the spectra of I Zw 18C, implying that ionizing massive stars are present. Hi

N. G. Guseva, Y. I. Izotov, P. Papaderos, F. H. Chaffee

We present the results of spectrophotometry and V,R,I, Halpha CCD photometry of the blue compact dwarf (BCD) galaxy SBS 0940+544. Broad-band images taken with the 2.1m KPNO and 1.23m Calar Alto telescopes reveal a compact high-surface-brightness H II region with ongoing star formation, located at the northwestern tip of the elongated low surface brightness (

Y. I. Izotov, F. H. Chaffee, R. F. Green

We present high-quality Keck telescope spectroscopic observations of the two metal-deficient blue compact dwarf (BCD) galaxies Tol 1214-277 and Tol 65. These data are used to derive the heavy-element and helium abundances. We find that the oxygen abundances in Tol 1214-277 and Tol 65 are the same, 12+logO/H=7.54+/-0.01, or Zsun/24, despite the different ioni

Y. I. Izotov, F. H. Chaffee, D. Schaerer

The results of deep long-slit spectroscopy of the extremely low-metallicity blue compact dwarf (BCD) galaxy SBS 0335-052 are presented. Down to intensity levels of 10^{-3 ... -4} of Hbeta, unprecedented for spectroscopy of extra-galactic giant H II regions, we detect numerous weak permitted and forbidden nebular lines in the brightest part of the galaxy. Wit

G. Stasinska, Y. I. Izotov

This paper investigates the effect of collisional enhancement of the hydrogen lines on the derivation of the helium abundances in low metallicity H II regions. For this, we have constructed a grid of photoionization models relevant for the analysis of giant \hii regions in blue compact galaxies. We show that the effect of collisional excitation on the Halpha

Masami Ouchi, Kazuhiro Shimasaku, Sadanori Okamura, Mamoru Doi

We study the luminosity function and the correlation function of about 1200 z~4 Lyman break galaxies (LBGs) with i&#39;<26 that are photometrically selected from deep BRi&#39; imaging data of a 618 arcmin^2 area in the Subaru/XMM-Newton Deep Field taken with Subaru Prime Focus Camera. The contamination and completeness of our LBG sample are evaluated, on the

R. Alvarez, A. Jorissen, B. Plez, D. Gillet

A tomographic method is described that makes it possible to follow the propagation of shock waves across the photosphere of long-period variable stars. The method relies on the correlation of the observed spectrum with numerical masks probing layers of different atmospheric depths. The formation depth of spectral lines is derived from synthetic spectra of no

Massimo Meneghetti, Matthias Bartelmann, Lauro Moscardini

Upcoming wide-area surveys in the submillimetre regime will allow the construction of complete galaxy cluster samples through their thermal Sunyaev-Zel&#39;dovich effect. We propose an analytic method to predict the number of gravitationally lensed giant arcs produced by the cluster sample expected to be detectable for the Planck satellite. The statistics of

Richard Ellis, Mike Santos, Jean-Paul Kneib, Konrad Kuijken

We discuss the physical nature of a remarkably faint pair of Lyman alpha-emitting images discovered close to the giant cD galaxy in the lensing cluster Abell 2218 (z=0.18) during a systematic survey for highly-magnified star-forming galaxies beyond z=5. A well-constrained mass model suggests the pair arises via a gravitationally-lensed source viewed at high

Myung Gyoon Lee, Eunhyeuk Kim, Doug Geisler, Terry Bridges

We present a preliminary analysis of HST-WFPC2 observations of globular cluster systems in the two brightest galaxies, UGC 9799 (cD) and NGC 1129 (non-cD), located in the center of rich clusters.

Xiaolei Zhang, Lee Feinberg, Dave Leisawitz, Douglas B. Leviton

We are developing a Wide-Field Imaging Interferometry Testbed (WIIT) in support of design studies for NASA&#39;s future space interferometry missions, in particular the SPIRIT and SPECS far-infrared/submillimeter interferometers. WIIT operates at optical wavelengths and uses Michelson beam combination to achieve both wide-field imaging and high-resolution sp

Sean A. Hartnoll, Eric G. Blackman

We calculate the iron line profiles from accretion discs with spiral velocity structures around Schwarzschild black holes. We find that quasi-periodic bumps appear in the the profiles, thereby providing a test for spiral wave patterns. This study is motivated by recent work showing that spiral density waves can result from MHD instabilities even in non-self-

R. Kurtev, L. Georgiev, J. Borissova, W. D. Li

King, Modjaz, & Li (1999) discovered Nova 1999 in IC1613 at Lick Observatory. Both Fugazza et al. (2000) and Borissova et al. (2000) questioned this classification, because they were able to detect the star on images obtained in previous years. In infrared frames taken on Oct. 15, 1998, the Nova 1999 has (J-K) = 1.14 and K = 14.69 mag. Our light curve study,

Yun Wang, Geoffrey Lovelace

Type Ia supernovae (SNe Ia) are currently the best probes of the dark energy in the universe. To constrain the nature of dark energy in a model-independent manner, we allow the density of dark energy, $ρ_X(z)$, to be an arbitrary function of redshift. Using simulated data from a space-based supernova pencil beam survey, we find that by optimizing the number

Marc Gagne, David Cohen, Stanley Owocki, Asif Ud-Doula

High-resolution X-ray spectra of high-mass stars and low-mass T-Tauri stars obtained during the first year of the Chandra mission are providing important clues about the mechanisms which produce X-rays on very young stars. For zeta Puppis (O4 If) and zeta Ori (O9.5 I), the broad, blue-shifted line profiles, line ratios, and derived temperature distribution s

H. H. Asatryan, H. M. Asatrian, C. Greub, M. Walker

We present in detail the calculation of the virtual O(alpha_s) corrections to the inclusive semi-leptonic rare decay b --> s l+ l-. We also include those O(alpha_s) bremsstrahlung contributions which cancel the infrared and mass singularities showing up in the virtual corrections. In order to avoid large resonant contributions, we restrict the invariant mass

H. -J. Grimm, M. Gilfanov, R. Sunyaev

We study the Log(N)-Log(S) and X-ray luminosity function in the 2-10 keV energy band, and the spatial (3-D) distribution of bright, log(L_X) > 34-35 erg/s, X-ray binaries in the Milky Way. In agreement with theoretical expectations and earlier results we found significant differences between the spatial distributions of low (LMXB) and high (HMXB) mass X-ray

Irina Dymnikova, Juergen Ulbricht, Jiawei Zhao

We review the experimental limits on mass of excited fundamental particles and contact interaction energy scale parameters $Λ$ for QCD, QED and electroweak reactions. In particular we have focused on the QED reaction $ \EEGG $ at the energies from 91GeV{} to 202GeV{} using the differential cross-sections measured by the L3 Collaboration from 1991 to 1999. A

Tal Alexander, Mario Livio

Some of the mass that feeds the growth of a massive black hole (BH) in a galactic center is supplied by tidal disruption of stars that approach it on unbound, low angular momentum orbits. For each star that is disrupted, others narrowly escape after being subjected to extreme tidal distortion, spin-up, mixing and mass-loss, which may affect their evolution a

Bozhidar Z. Iliev

Some elements of classical mechanics and classical statistical mechanics are formulated in terms of fibre bundles. In the bundle approach the dynamical and distribution functions are replaced by liftings of paths in a suitably chosen bundle. Their time evolution is described by appropriate linear transports along paths in it or, equivalently, by correspondin

C. T. Ridgely

Herein the Casimir effect is used to present a simple macroscopic view on creating exotic matter. The energy arising between two nearly perfectly conducting parallel plates is shown to become increasingly negative as the plate separation is reduced. It is proposed that the Casimir energy appears increasingly negative simply because the vacuum electromagnetic

C. T. Ridgely

A current approach to the problem of inertia suggests that the origin of the inertial properties of matter is the interaction between matter and vacuum electromagnetic zero-point radiation. Herein, it is shown that zero-point phenomena can be treated as the origin of inertia only when one chooses to ignore the mass-energy content of matter. In the absence of

Lorenz Halbeisen

We investigate families of partitions of omega which are related to special coideals, so-called happy families, and give a dual form of Ramsey ultrafilters in terms of partitions. The combinatorial properties of these partition-ultrafilters, which we call Ramseyan ultrafilters, are similar to those of Ramsey ultrafilters. For example it will be shown that du

Lorenz Halbeisen

In this article we compare the well-known Ramsey property with a dual form of it, the so called dual-Ramsey property (which was suggested first by Carlson and Simpson). Even if the two properties are different, it can be shown that all classical results known for the Ramsey property also hold for the dual-Ramsey property. We will also show that the dual-Rams

Lorenz Halbeisen

In this article we investigate the dual-shattering cardinal H, the dual-splitting cardinal S and the dual-reaping cardinal R, which are dualizations of the well-known cardinals h (the shattering cardinal, also known as the distributivity number of P(omega) modulo finite, s (the splitting number) and r (the reaping number). Using some properties of the ideal

R. Blute, I. T. Ivanov, P. Panangaden

We give a mathematical framework to describe the evolution of an open quantum systems subjected to finitely many interactions with classical apparatuses. The systems in question may be composed of distinct, spatially separated subsystems which evolve independently but may also interact. This evolution, driven both by unitary operators and measurements, is co

Fatimah Shojai, Ali Shojai

In this paper we shall address this problem: Is quantum gravity constraints algebra closed and what are the quantum Einstein equations. We shall investigate this problem in the de-Broglie--Bohm quantum theory framework. It is shown that the constraint algebra is weakly closed and the quantum Einstein&#39;s equations are derived.

M. Eracleous, J. C. Shields, G. Chartas, E. C. Moran

We use X-ray observations of three galaxies hosting LINERs (NGC 404, NGC 4736, NGC 4579) with Chandra to study their power sources. We find very diverse properties within this small group: NGC 404 has an X-ray-faint nucleus with a soft, thermal spectrum, NGC 4736 harbors a plethora of discrete X-ray sources in and around its nucleus, and NGC 4579 has a domin

Y. Takeda, B. Sato, E. Kambe, W. Aoki

By using the high-dispersion spectra of 14 bright planet-harboring stars (along with 4 reference stars) observed with the new coude echelle spectrograph at Okayama Astrophysical Observatory, we investigated the abundances of volatile elements (C, N, O, S, Zn; low condensation temperature Tc) in order to examine whether these show any significant difference c

Ph. Podsiadlowski, K. Nomoto, K. Maeda, T. Nakamura

Israelian et al. (1999) showed that the stellar companion of the black-hole binary Nova Sco is polluted with material ejected in the supernova that accompanied the formation of the black-hole primary. Here we systematically investigate the implications of these observations for the black-hole formation process. Using a variety of supernova models, including

Tiziana Di Matteo, Rosalba Perna, Tom Abel, Martin J. Rees

Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature. This so-called 21cm tomography should reveal important information on the physical state of the intergalactic medium at h

J. Swank, C. Markwardt

Starting in 1999, the Rossi X-ray Timing Explorer (RXTE) has monitored the central bulge region of the Galaxy with the Proportional Counter Array (PCA), resolving about 50 binary X-ray sources, including 18 sources discovered by RXTE and BeppoSAX. The accretion rates that RXTE observed from these sources ranged from highs approaching Eddington limits to lows

Hidekazu Fujiwara, Makoto Makita, Takizo Nagae, Takuya Matsuda

The hydrodynamic behavior of an accretion disk in a close binary system is numerically simulated. Calculation is made for a region including the compact star and the gas-supplying companion. The equation of state is that of an ideal gas characterized by the specific heat ratio $γ$. Two cases with $γ$ of 1.01 and 1.2 are studied. Our calculations show that th

Li-Chung Ku, S. A. Trugman, J. Bonca

Based on a recently developed variational method, we explore the properties of the Holstein polaron on an infinite lattice in $D$ dimensions, where $ 1 \le D \le 4$. The computational method converges as a power law, so that highly accurate results can be achieved with modest resources. We present the most accurate ground state energy (with no small paramete

J. Gutowski

We examine the low-energy dynamics of CP^1 lumps coupled to gravity, taking into account the gravitational back-reaction of the spacetime geometry. We show that the single lump moduli space is equipped with a three-dimensional metric, and we derive stability bounds on the scalar coupling constant. We also derive an expression for the multi-lump moduli space

Shin&#39;ichi Nojiri, Sergei D. Odintsov

The thermodynamics of d5 AdS BHs with positive, negative or zero curvature spatial section in higher derivative (HD) gravity is described. HD contribution to free energy may change its sign which leads to more complicated regime for Hawking-Page phase transitions. Some variant of d5 HD gravity is dual to ${\cal N}=2$ $Sp(N)$ SCFT up to the next-to-leading or

K. Abe, The Belle Collaboration

We report the first observation of color-suppressed $\bar{B}{}^0 \to D^0 π^0$, $D^{*0} π^0$, $D^{0} η$, and $D^{0}ω$ decays and evidence for $\bar{B}{}^0 \to D^{*0} η$ and $D^{*0}ω$. The branching fractions are found to be ${\cal B} (\bar{B}{}^0 \to D^0 π^0) = (3.1 \pm 0.4 \pm 0.5) \times 10^{-4}$, ${\cal B} (\bar{B}{}^0 \to D^{*0} π^0) = (2.7 ^{+0.8}_{-0.7}

Jacques Bros, Detlev Buchholz

It is shown that the timelike asymptotic properties of thermal correlation functions in relativistic quantum field theory can consistently be described in terms of free fields carrying some stochastic degree of freedom which couples to the thermal background. These ``asymptotic thermal fields&#39;&#39; have specific algebraic properties (commutation relation

Jiri Bajer, Adam Miranowicz

In this review, we compare different descriptions of photon-number statistics in harmonic generation processes within quantum, classical and semiclassical approaches. First, we study the exact quantum evolution of the harmonic generation by applying numerical methods including those of Hamiltonian diagonalization and global characteristics. We show explicitl

C. T. Ridgely

A recent proposal asserts that gravitational forces arise due to an interaction between matter and vacuum electromagnetic zero-point radiation. The present analysis demonstrates that forces induced on matter by zero-point radiation arise in addition to gravitational forces. It is argued that zero-point radiation should be red-shifted near large gravitational

C. T. Ridgely

Current approaches to the problem of inertia attempt to explain the inertial properties of matter by expressing the inertial mass appearing in Newton&#39;s second law of motion in terms of some other more fundamental interaction. One increasingly popular approach explains inertial and gravitational forces as drag forces arising due to quantum vacuum zero-poi

A. Yu. Korchin

Magnetic moment and radius of the nucleon are calculated in a nonlocal extension of the chiral linear σ-model. Properties of the nonlocal model under the vector and axial transformations are considered. The conserved electromagnetic and vector currents, and partially conserved axial vector current are obtained. In the calculation of the nucleon electromagnet

N. Itagaki, S. Hirose, T. Otsuka, S. Okabe

The triaxial deformation in $^{10}$Be is investigated using a microscopic $α+α+n+n$ model. The states of two valence neutrons are classified based on the molecular-orbit (MO) model, and the $π$-orbit is introduced about the axis connecting the two $α$-clusters for the description of the rotational bands. There appear two rotational bands comprised mainly of

M. R. Dragowsky, A. Hamer, Y. D. Chan, R. Deal

A calibration source using gamma-rays from 16N (t_1/2 = 7.13 s) beta-decay has been developed for the Sudbury Neutrino Observatory (SNO) for the purpose of energy and other calibrations. The 16N is produced via the (n,p) reaction on 16O in the form of CO2 gas using 14-MeV neutrons from a commercially available Deuterium-Tritium (DT) generator. The 16N is pro

Zhongmin Shen

A Riemannian metric is of constant curvature if and only if it is locally projectively flat. There are infinitely many locally projectively flat Finsler metrics of constant curvature, that are special solutions to the Hilbert&#39;s Fourth Problem. In this paper, we use the technique in the paper titled &#34;Finsler metrics with K=0 and S=0&#34; (math.DG/0109

Lev A. Borisov, Anvar R. Mavlyutov

We propose a construction of string cohomology spaces for Calabi-Yau hypersurfaces that arise in Batyrev&#39;s mirror symmetry construction. The spaces are defined explicitly in terms of the corresponding reflexive polyhedra in a mirror-symmetric manner. We draw connections with other approaches to the string cohomology, in particular with the work of Chen a

V. Hardt, R. Mennicken, A. K. Motovilov

We construct operators which factorize the transfer function associated with a non-self-adjoint 2x2 operator matrix whose diagonal entries can have overlapping spectra and whose off-diagonal entries are unbounded operators.

An-Min Li, Quan Zheng, Guosong Zhao, Hao Chen

The paper was removed.

C. Shio

There have been comments on the starting paper, hep-th/0106074, which point out unclear motivation and definitions on noncommutative momentum introduced. Therefore, to give more clear presentation, this paper is withdrawn.

C. Shio

There have been comments on the starting paper, hep-th/0106074, which point out unclear motivation and definitions on noncommutative momentum introduced. Therefore, this paper is withdrawn by the author for more clear presentation.

C. Shio

There have been comments on the starting paper, hep-th/0106074, which point out unclear motivation and definitions on noncommutative momentum introduced. Thus, this paper is withdrawn by the author for more clear presentation.

C. Shio

There have been comments on this paper which point out unclear motivation and definitions on noncommutative momentum introduced. Therefore, this paper is withdrawn by the author for more clear presentation.

Pascal Vaillant

Allowing users to interact through language borders is an interesting challenge for information technology. For the purpose of a computer assisted language learning system, we have chosen icons for representing meaning on the input interface, since icons do not depend on a particular language. However, a key limitation of this type of communication is the ex

James W. Dufty

The shear stress autocorrelation function has been studied recently by molecular dynamics simulation using the 1/q^n potential for very large n. The results are analyzed and interpreted here by comparing them to the shear stress response function for hard spheres. It is shown that the hard sphere response function has a singular contribution and that this is

Anirban Chakraborti

We study a variant of the Cont-Bouchaud model which utilizes the perco lation approach of multi-agent simulations of the stock market fluctuations. Here, instead of considering the relative price change as the difference of the total demand and total supply, we consider the relative price change to be proportiona l to the ``relative&#39;&#39; difference of d

N. S. Schulz, W. Cui, C. R. Canizares, H. L. Marshall

We observed the black hole candidate Cyg X-1 for 15 ks with the High-Energy Transmission Grating Spectrometer aboard the CHANDRA X-ray Observatory. The source was observed during a period of intense flaring activity, so it was about a factor of 2.5 brighter than usual, with a 0.5-10 keV (1-24 A) luminosity of 1.6x10^37 erg/s (at a distance of 2.5 kpc). The s

D. Garcia-Alvarez, B. H. Foing, D. Montes, J. M. Oliveira

We present simultaneous and continuous observations of H_alpha, H_beta, NaI D_1, D_2, HeI D_3 and CaII H & K lines of the chromospherically active binary HR 1099. We have observed HR 1099 for more than 3 weeks almost continuously and monitored two flares. An increase in H_alpha and CaII H & K, H_beta and HeI D_3 and a strong filling-in of the NaI D_1, D_2 du

H. M. Hernandez-Toledo, I. Puerari

We present multicolour broad band ($BVRI$) photometry for a sample of 33 spiral-spiral (S+S) binary galaxies drawn from the Karachentsev Catalogue of Isolated Pairs of Galaxies (KPG). The data is part of a joint observational programme devoted to systematic photometric study of one of the most complete and homogeneous pair samples available in the literature

A. C. Funk, M. G. Raymer

We propose a new scheme for quantum key distribution using macroscopic non-classical pulses of light having of the order 10^6 photons per pulse. Sub-shot-noise quantum correlation between the two polarization modes in a pulse gives the necessary sensitivity to eavesdropping that ensures the security of the protocol. We consider pulses of two-mode squeezed li

Xiao-Gang Wen

The existence of light (a massless U(1) gauge boson) is one of unresolved mysteries in nature. In this paper, we would like to propose that light is originated from certain quantum orders in our vacuum. We will construct quantum models on lattice to demonstrate that some quantum orders can give rise to light without breaking any symmetries and without any fi

S. Kondratyuk, O. Scholten

The Gerasimov-Drell-Hearn and Baldin-Lapidus sum rules are evaluated in the dressed K-matrix model for photon-induced reactions on the nucleon. For the first time the sum $α+β$ of the electric and magnetic polarisabilities and the forward spin polarisability $γ_0$ are explicitly calculated in two alternative ways -- from the sum rules and from the low-energy

Tomomi Ishikawa, Shin-Ichiro Kuroki, Akifumi Sako

We found an exact solution of elongated U(1) instanton on noncommutative R^4 for general instanton number k. The deformed ADHM equation was solved with general k and the gauge connection and the curvature were given explicitly. We also checked our solutions and evaluated the instanton charge by a numerical calculation.

D. Fargion, M. Khlopov

The existence of antimatter stars in the Galaxy as possible signature for inflationary models with non-homogeneous baryo-synthesis may leave the trace by antimatter cosmic rays as well as by their secondaries (anti-planets and anti-meteorites) diffused bodies in our galactic halo. The anti-meteorite flux may leave its explosive gamma signature by colliding o

Adam Burrows, Adam J. Burgasser, J. Davy Kirkpatrick, James Liebert

We have generated new, self-consistent spectral and atmosphere models for the effective temperature range 600 K to 1300 K thought to encompass the known T dwarfs. For the first time, theoretical models are compared with a {\it family} of measured T dwarf spectra at wavelengths shortward of $\sim$1.0 micron. By defining spectral indices and standard colors in

H. Maebashi, K. Miyake, C. M. Varma

Systematic theoretical results for the effects of a dilute concentration of magnetic impurities on the thermodynamic and transport properties in the region around the quantum critical point of a ferromagnetic transition are obtained. In the quasi-classical regime, the dynamical spin fluctuations enhance the Kondo temperature. This energy scale decreases rapi

Pankaj S. Joshi, Naresh Dadhich, Roy Maartens

We investigate what are the key physical features that cause the development of a naked singularity, rather than a black hole, as the end-state of spherical gravitational collapse. We show that sufficiently strong shearing effects near the singularity delay the formation of the apparent horizon. This exposes the singularity to an external observer, in contra

Aníbal Iucci, Carlos Naón

We present an alternative way to determine the unknown parameter associated to a gaussian approximation in a generic two-dimensional model. Instead of the standard variational approach, we propose a procedure based on a quantitative prediction of conformal invariance, valid for systems in the scaling regime, away from criticality. We illustrate our idea by c

ZEUS Collaboration, S. Chekanov

Searches in ep collisions for heavy excited fermions have been performed with the ZEUS detector at HERA. Excited states of electrons and quarks have been searched for in e^+p collisions at a centre-of-mass energy of 300 GeV using an integrated luminosity of 47.7 pb^-1. Excited electrons have been sought via the decays e*->egamma, e*->eZ and e*->nuW. Excited

Pran Nath, Raza M. Syed

A recently derived basic theorem on the decomposition of SO(2N) vertices is used to obtain a complete analytic determination of all SO(10) invariant cubic superpotential couplings involving $16_{\pm}$ semispinors of SO(10) chirality $\pm$ and tensor representations. In addition to the superpotential couplings computed previously using the basic theorem invol

J. R. Espinosa, I. Navarro

A radiatively-corrected mixing angle has to be independent of the choice of renormalization scale to be a physical observable. At one-loop in MS-bar, this only occurs for a particular value, p*, of the external momentum in the two-point functions used to define the mixing angle: p*^2=(M1^2+M2^2)/2, where M1, M2 are the physical masses of the two mixed partic

Magali Benoit, Simona Ispas, Mark E. Tuckerman

We present the results of first-principles molecular-dynamics simulations of molten silicates, based on the density functional formalism. In particular, the structural properties of a calcium aluminosilicate $ [$ CaO-Al$_2$O$_3$-SiO$_2$ $ ]$ melt are compared to those of a silica melt. The local structures of the two melts are in good agreement with the expe

John Ellis, Junji Hisano, Smaragda Lola, Martti Raidal

We study CP violation in the lepton sector of the supersymmetric extension of the Standard Model with three generations of massive singlet neutrinos with Yukawa couplings $Y_ν$ to lepton doublets, in a minimal seesaw model for light neutrino masses and mixing. This model contains six physical CP-violating parameters, namely the phase $δ$ observable in oscill

G. W. Delius, N. J. MacKay, B. J. Short

For the classical principal chiral model with boundary, we give the subset of the Yangian charges which remains conserved under certain integrable boundary conditions, and extract them from the monodromy matrix. Quantized versions of these charges are used to deduce the structure of rational solutions of the reflection equation, analogous to the &#39;tensor

Simona Ispas, Magali Benoit, Philippe Jund, Remi Jullien

The structure and the electronic properties of a sodium tetrasilicate (Na${}_2$Si${}_4$O${}_9$) glass were studied by combined Car-Parrinello and classical molecular-dynamics simulations. The glass sample was prepared using a method employed recently in a study of a silica glass [M. Benoit {\it et al}, Euro. Phys. J. B {\bf 13}, 631 (2000)]. First we generat

T. Hattori, T. Hasuike, S. Wakaizumi

We investigate the CP violation effect and the matter effect in the long-baseline neutrino oscillations in the four-neutrino model with mass scheme of the two pairs of two close masses separated by a gap of the order of 1 eV by using the constraints on the mixing matrix derived from the solar neutrino deficit, atmospheric neutrino anomaly, LSND experiments,

Guangjun Mao, Akira Iwamoto, Zhuxia Li

We study the effects of strong magnetic fields on the neutron star structure. If the interior field of a star is on the same order of the surface field currently observed, the influences of the magnetic field on the star mass and radius are negligible. If one assumes that the internal magnetic field can be as large as that estimated from the scalar virial th

M. Rausch de Traubenberg, M. J. Slupinski

We consider the problem of representing the Kac-Moody algebra $\mathfrak{g}(N)$ specified by an $r\times r$ indecomposable generalised Cartan matrix $N$ as vector fields on the torus ${{\bb C}^*}^r$. It is shown that, if the representations are of a certain form, this is possible if and only if $\mathfrak{g}(N)\cong sl(r+1,{\bb C})$ or $\tilde{sl}(r,{\bb C})

S. Mo, J. Hove, A. Sudbo

We present results from large-scale Monte Carlo simulations on the full Ginzburg-Landau (GL) model, including fluctuations in the amplitude and the phase of the matter-field, as well as fluctuations of the non-compact gauge-field of the theory. {}From this we obtain a precise critical value of the GL parameter $\kct$ separating a first order metal to superco

S. Recksiegel, Y. Sumino

We examine the total energy E_tot(r) = 2 m_pole + V_QCD(r) of the b\bar b system within perturbative QCD up to O(α_S^3). We extend a previous analysis by incorporating effects of the non-zero charm-quark mass in loops. We find that, once the renormalon cancellation is performed, E_tot(r) agrees well with typical phenomenological potentials for heavy quarkoni

Seong Chan Park, H. S. ~Song

We study the effects of extra dimensions on the muon anomalous magnetic moment with brane fluctuation. Since the coupling is naturally suppressed if brane fluctuation is considered by exponential softening factor for heavier states, the contribution from the whole Kaluza-Klein graviton tower is shown to be finite. The recent BNL E821 result is accomodated wi

Stefan Bornholdt, Torsten Roehl

A mechanism for self-organization of the degree of connectivity in model neural networks is studied. Network connectivity is regulated locally on the basis of an order parameter of the global dynamics which is estimated from an observable at the single synapse level. This principle is studied in a two-dimensional neural network with randomly wired asymmetric

Cesar Miquel, Juan Pablo Paz, Marcos Saraceno, Emmanuel Knill

Determining the state of a system and measuring properties of its evolution are two of the most important tasks a physicist faces. For the first purpose one can use tomography, a method that after subjecting the system to a number of experiments determines all independent elements of the density matrix. For the second task, one can resort to spectroscopy, a

Mart de Graaf, Ronald de Wolf

The classical Yao principle states that the complexity R_epsilon(f) of an optimal randomized algorithm for a function f with success probability 1-epsilon equals the complexity max_mu D_epsilon^mu(f) of an optimal deterministic algorithm for f that is correct on a fraction 1-epsilon of the inputs, weighed according to the hardest distribution mu over the inp

Peter Rowlands, J. P. Cullerne

The nilpotent formalism for the Dirac equation, outlined in previous papers,is applied to QED. It is shown that what is usually described as &#39;renormalization&#39; is effectively a statement of the fact that the nilpotent formulation is automatically second quantized and constrains the field into producing finite values for fundamental quantities.

Peter Hoyer, Ronald de Wolf

We prove new bounds on the quantum communication complexity of the disjointness and equality problems. For the case of exact and non-deterministic protocols we show that these complexities are all equal to n+1, the previous best lower bound being n/2. We show this by improving a general bound for non-deterministic protocols of de Wolf. We also give an O(sqrt

V. V. Kudryashov, Yu. V. Vanne

The uniformly valid approximation to solutions of the radial Schrödinger equation with power-law potentials are obtained by means of the explicit summation of the leading constituent WKB series.

Takayuki Miyadera, Akira Shimizu

We study a general macroscopic quantum system of a finite size, which will exhibit a symmetry breaking if the system size goes to infinity, when the system interacts with an environment. We evaluate the decoherence rates of the anomalously fluctuating vacuum (AFV), which is the symmetric ground state, and the pure phase vacua (PPVs). By making full use of th

Yoshio Nishiyama

A trajectory of a harmonic oscillator obeying the Schreodinger wave equation is exactly derived and illustrated. The trajectory resembles well the classical orbit between the turning points, and also runs through the tunneling region. The dynamics of the `particle&#39; motion and the wave function associated with the motion are proposed. The period of a roun

Pengfei Zhuang, Joerg Huefner

The transverse momentum dependence of J/Psi suppression in relativistic heavy ion collisions is calculated from initial state gluon rescattering not only with nucleons but also with prompt gluons produced in nucleon-nucleon collisions in the early phase of the reaction. The second mechanism is new and turns out to be important in a description of the data fo

Gerald T. Garvey, Jen-Chieh Peng

A surprisingly large asymmetry between the up and down sea quark distributions in the nucleon has been observed in recent deep inelastic scattering and Drell-Yan experiments. This result strongly suggests that the mesonic degrees of freedom play an important role in the description of the parton distributions of the hadronic sea. In this article, we review t

S. Pianegonda, J. R. Iglesias, G. Abramson, J. L. Vega

We present a simplified model for the exploitation of finite resources by interacting agents, where each agent receives a random fraction of the available resources. An extremal dynamics ensures that the poorest agent has a chance to change its economic welfare. After a long transient, the system self-organizes into a critical state that maximizes the averag

Cristian Degli Esposti Boschi, Guillermo Ortega, Enrique Louis

We address the distinction between dynamical and additive noise in time series analysis by making a joint evaluation of both the statistical continuity of the series and the statistical differentiability of the reconstructed measure. Low levels of the latter and high levels of the former indicate the presence of dynamical noise only, while low values of the

I. Towers, A. V. Buryak, R. A. Sammut, B. A. Malomed

We investigate stability of (2+1)-dimensional ring solitons of the nonlinear Schrodinger equation with focusing cubic and defocusing quintic nonlinearities. Computing eigenvalues of the linearised equation, we show that rings with spin (topological charge) s=1 and s=2 are linearly stable, provided that they are very broad. The stability regions occupy, respe

Sen-yue Lou, Xiao-yan Tang, Qing-Ping Liu, T. Fukuyama

In this paper, we study the possible second order Lax operators for all the possible (1+1)-dimensional models with Schwarz variants and some special types of high dimensional models. It is shown that for every (1+1)-dimensional model and some special types of high dimensional models which possess Schwarz variants may have a second order Lax pair. The exiplic

Adrian Vasiu

We prove the Mumford-Tate conjecture for those abelian varieties over number fields, whose simple factors of their adjoint Mumford-Tate groups have over $\dbR$ certain (products of) non-compact factors. In particular, we prove this conjecture for the orthogonal case ($B_n$ and $D_n^{\dbR}$ Shimura types). We construct embeddings of Shimura varieties of (whos

Richard P. Stanley

Nazarov and Tarasov recently generalized the notion of the rank of a partition to skew partitions. We give several characterizations of the rank of a skew partition and one possible characterization that remains open. One of the characterizations involves the decomposition of a skew shape into a minimal number of border strips, and we develop a theory of the

C. Robin Graham, Maciej Zworski

This paper describes the connection between scattering matrices on conformally compact asymptotically Einstein manifolds and conformally invariant objects on their boundaries at infinity. The conformally invariant powers of the Laplacian arise as residues of the scattering matrix and Branson&#39;s Q-curvature in even dimensions as a limiting value. The integ

Pavol Severa, Alan Weinstein

We study a modification of Poisson geometry by a closed 3-form. Just as for ordinary Poisson structures, these &#34;twisted&#34; Poisson structures are conveniently described as Dirac structures in suitable Courant algebroids. The additive group of 2-forms acts on twisted Poisson structures and permits them to be seen as glued from ordinary Poisson structure