July 2003 arXiv papers — page 3

Yukinori Nagatani

The Hawking radiation in the vacuum of the spontaneous symmetry breaking in the gauge-Higgs-Yukawa theory is investigated by a general relativistic formulation of the the ballistic model. The restoration of the symmetry on the horizon and the formation of the spherical domain wall around the black hole are shown even if the Hawking temperature is lower than

Friedemann Brandt, C. P. Martin, F. Ruiz Ruiz

We show that noncommutative gauge theories with arbitrary compact gauge group defined by means of the Seiberg-Witten map have the same one-loop anomalies as their commutative counterparts. This is done in two steps. By explicitly calculating the $ε^{\m_1\m_2\m_3\m_4}$ part of the renormalized effective action, we first find the would-be one-loop anomaly of t

B. Bambah, C. Mukku

A complete quantum field theoretic study of charged and neutral particle creation in a rapidly/adiabatically expanding Friedman-Robertson-Walker metric for an O(4) scalar field theory with quartic interactions (admitting a phase transition) is given. Quantization is carried out by inclusion of quantum fluctuations. We show that the quantized Hamiltonian admi

Michael Luke

The use of inclusive B decays to determine |V_{ub}|, |V_{cb}|, m_b and heavy quark matrix elements via spectral moments is discussed.

A. H. Hoang

The three-loop non-mixing contributions to the anomalous dimension of the leading order quark pair production current in non-relativistic QCD are computed. It is demonstrated that the renormalization procedure can only be carried out consistently if the dynamics of both soft and the ultrasoft degrees of freedom is present for all scales below the heavy quark

R. Aleksan, T. C. Petersen

We present a method to measure the weak phase 2beta+gamma in the three-body decay B0 -> D+- Ks pi-+. These decays are mediated by interfering amplitudes which are color-allowed and hence relatively large. In addition, the three-body decay helps to resolve discrete ambiguities present in measurements of the weak phase. The experimental implications are discus

Dmitry Borisyuk, Manfried Faber, Alexander Kobushkin

From the interpretation of the $Θ^+$ baryon resonance as an excitation of the ``skyrmion liquid'' with SU(3) flavor symmetry $\bar{10}$ we deduce a new series of baryons, $Θ_1^{++}$, $Θ_1^{+}$ and $Θ_1^0$, situated at the top of the 27-plet of SU(3) flavor, with hypercharge Y=2, isospin T=1 and spin $J=\frac32$. The mass of $Θ_1$ is estimated 55 MeV/

A. V. Belitsky, D. Müller

We evaluate the differential cross section for the electroproduction of lepton pairs off a polarized nucleon target in the generalized Bjorken region to leading power accuracy in hard momentum. We discuss the importance of this process for phenomenology of generalized parton distributions. A special attention is given to the sensitivity of physical observabl

C. P. Korthals Altes

TeV size extra dimensions introduce domain walls. Such walls are inconsistent with CMB anisotropies. Either inflationary dynamics washes them out, or the reheating temperature is lower then the temperature at which the walls start forming networks. As the restoration of the symmetry is non-perturbative we have performed 5d lattice simulations which show the

C. Isola, M. Ladisa, G. Nardulli, P. Santorelli

We evaluate the decays B => K* pi, K (rho,omega,phi) adding the long distance charming penguin contributions to the short distance: Tree+Penguin amplitudes. We estimate the imaginary part of the charming penguin by an effective field theory inspired by the Heavy Quark Effective Theory and parameterize its real part. The final results for branching ratios dep

M. Hirsch, W. Porod

Supersymmetry with broken R-parity can explain the neutrino mass squared differences and mixing angles observed in neutrino oscillation experiments. In the minimal model, where R-parity is broken only by bilinear terms, certain decay properties of the lightest supersymmetric particle (LSP) are correlated with neutrino mixing angles. Here we consider chargino

Masanori Morishita, Masaki Arima

Making use of the quasi-coherent state developed by Eriksson et al., we can find a nucleon solution accompanied by the pion field with trivial topology. We compare our approach with other related works, and examine a coherent state description of pions in the baryon structure. Our solution suggests a kind of nucleon resonance due to the topological change of

Mitsuru Kakizaki, Masahiro Yamaguchi

It is pointed out that heavy top quark mass can be attributed to a singular normalization of its kinetic term, in which rescaling into canonical one yields large top Yukawa coupling. We pursue this novel possibility in a democratic mass matrix model where only the normalization of the third generation can be different from that of the other two generations.

Masako Bando, Midori Obara

After a brief review of quark-lepton relations in grand unified theories (GUT), we show that the Pati-Salam relation with only one type of Higgs field configuration with "four zero symmetric texture" can reproduce two large neutrino mixings as well as observed mass differences. This is quite in contrast to the case of SU(5) where bi-large mixings ess

B. Aubert, BABAR Collaboration

We present preliminary measurements of branching fractions and CP-violating charge asymmetries in B-meson decays to rho pi. The data sample comprises 89 million Y(4S) --> BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find the charge-averaged branching fractions B(B+ --> rho+ pi0) = (11.0 +/- 1.9(stat.) +

Gianluca Usai

Since 1986, several heavy ion experiments have studied some signatures of the formation of the quark-gluon plasma and a few exciting results have been found. However, some important questions are still unanswered and require new measurements. The NA60 experiment, with a new detector concept that vastly improves dimuon detection in proton-nucleus and heavy-io

P. Astone, D. Babusci, M. Bassan, P. Carelli

Resonant gravitational wave detectors with an observation bandwidth of tens of hertz are a reality: the antenna Explorer, operated at CERN by the ROG collaboration, has been upgraded with a new read-out. In this new configuration, it exhibits an unprecedented useful bandwidth: in over 55 Hz about its frequency of operation of 919 Hz the spectral sensitivity

Lorenzo Iorio

Testing the effects predicted by the General Theory of Relativity, in its linearized weak field and slow motion approximation, in the Solar System is difficult because they are very small. Among them the post-Newtonian gravitomagnetic Lense-Thirring effect, or dragging of the inertial frames, on the orbital motion of a test particle is very interesting and,

Florian Conrady, Luisa Doplicher, Robert Oeckl, Carlo Rovelli

We consider a local formalism in quantum field theory, in which no reference is made to infinitely extended spacial surfaces, infinite past or infinite future. This can be obtained in terms of a functional W[f,S] of the field f on a closed 3d surface S that bounds a finite region R of Minkowski spacetime. The dependence of W on S is governed by a local covar

Nir Friedman, Joseph Y. Halpern

The study of belief change has been an active area in philosophy and AI. In recent years two special cases of belief change, belief revision and belief update, have been studied in detail. In a companion paper, we introduce a new framework to model belief change. This framework combines temporal and epistemic modalities with a notion of plausibility, allowin

Nir Friedman, Joseph Y. Halpern

Belief change is a fundamental problem in AI: Agents constantly have to update their beliefs to accommodate new observations. In recent years, there has been much work on axiomatic characterizations of belief change. We claim that a better understanding of belief change can be gained from examining appropriate semantic models. In this paper we propose a gene

Joseph Y. Halpern, Riccardo Pucella

We present a propositional logic %which can be used to reason about the uncertainty of events, where the uncertainty is modeled by a set of probability measures assigning an interval of probability to each event. We give a sound and complete axiomatization for the logic, and show that the satisfiability problem is NP-complete, no harder than satisfiability f

Jonathan P. Bowen

Physical disabled access is something that most cultural institutions such as museums consider very seriously. Indeed, there are normally legal requirements to do so. However, online disabled access is still a relatively novel and developing field. Many cultural organizations have not yet considered the issues in depth and web developers are not necessarily

C. F. M. Vermeulen

In this paper we adapt the definitions and results from Apt and Vermeulen on `First order logic as a constraint programming language' (in: Proceedings of LPAR2001, Baaz and Voronkov (eds.), Springer LNAI 2514) to include important ideas about search and choice into the system. We give motivating examples. Then we set up denotational semantics for first o

Saverio Perugini, Marcos Andre Goncalves, Edward A. Fox

Recommender systems attempt to reduce information overload and retain customers by selecting a subset of items from a universal set based on user preferences. While research in recommender systems grew out of information retrieval and filtering, the topic has steadily advanced into a legitimate and challenging research area of its own. Recommender systems ha

R. J. Magyar, A. Fleszar, E. K. U. Gross

The electronic structure of noble-gas solids is calculated within density functional theory's exact-exchange method (EXX) and compared with the results from the local-density approximation (LDA). It is shown that the EXX method does not reproduce the fundamental energy gaps as well as has been reported for semiconductors. However, the EXX-Kohn-Sham energ

Matthias J. Graf, Carl W. Greeff, Jonathan C. Boettger

The lattice vibrations are determined in the quasi-harmonic approximation for elemental Au and Cu to twice their normal density by first-principles electronic band-structure calculations. It is found for these materials that the important moments of the phonon density of states can be obtained to high accuracy from short-ranged force constant models. We disc

L. I. Deych, M. V. Erementchouk, A. A. Lisyansky

It is shown that it is possible to significantly modify optical spectra of Bragg multiple quantum well structures by introducing wells with different exciton energies. The reflection spectrum of the resulting structures is characterized by high contrast and tuning possibilities.

Francesco Ancilotto, M. Mercedes Calbi, Milton W. Cole, Silvina M. Gatica

Three problems are considered in which inhomogeneous broadening can yield unusual consequences. One problem involves the energy levels of atoms moving within nanopores of nearly cylindrical cross section. A second involves atomic or molecular motion in a quasi-one dimensional interstitial channel within a bundle of carbon nanotubes. The third problem involve

P. Ao, L. Yin

We discuss two aspects, the in vivo and in vitro difference and the modeling of noise, of integrative modeling of network dynamics in biology, using phage lambda as an example. We believe those two aspects have not been seriously considered, and the including of them may be enough to solve the outstanding stability and robustness puzzle of in gene regulatory

Pinaki Sengupta

The spin-Peierls transition in the ground state of a quasi-one-dimensional spin-1/2 Heisenberg model coupled to adiabatic bond phonons is studied using a quantum Monte Carlo (QMC) method. The transition from a gapless Neel state to a spin-gapped Peierls state is explored in the parameter space spanned by the spatial anisotropy and the strength of spin-lattic

Paolo Tommasini, E. J. V. de Passos, M. O. C. Pires, A. F. R. de Toledo Piza

We present a generalization of the Hartree-Fock Bogoliubov (HFB) theory in which the coupling between one and two quasi-particles is taken into account.This is done by writing the excitation operators as linear combinations of one and two HFB quasi-particles. The excitation energies and the quasi-particle amplitudes are given by generalized Bogoliubov equati

E. Ben-Naim, P. L. Krapivsky

The largest component (``the leader'') in evolving random structures often exhibits universal statistical properties. This phenomenon is demonstrated analytically for two ubiquitous structures: random trees and random graphs. In both cases, lead changes are rare as the average number of lead changes increases quadratically with logarithm of the syste

M. C. Rogge, C. Fuehner, U. F. Keyser, R. J. Haug

We have combined direct nanofabrication by local anodic oxidation with conventional electron-beam lithography to produce a parallel double quantum dot based on a GaAs/AlGaAs heterostructure. The combination of both nanolithography methods allows to fabricate robust in-plane gates and Cr/Au top gate electrodes on the same device for optimal controllability. T

S. R. Manmana, V. Meden, R. M. Noack, K. Schoenhammer

We study the zero-temperature phase diagram of the half-filled one-dimensional ionic Hubbard model. This model is governed by the interplay of the on-site Coulomb repulsion and an alternating one-particle potential. Various many-body energy gaps, the charge-density-wave and bond-order parameters, the electric as well as the bond-order susceptibilities, and t

M. Anghel, Zoltan Toroczkai, Kevin E. Bassler, G. Korniss

Using the minority game as a model for competition dynamics, we investigate the effects of inter-agent communications on the global evolution of the dynamics of a society characterized by competition for limited resources. The agents communicate across a social network with small-world character that forms the static substrate of a second network, the influe

M. Di Ventra, Yu-Chang Chen, T. N. Todorov

The expression for the force on an ion in the presence of current can be derived from first principles without any assumption about its conservative character. However, energy functionals have been constructed that indicate that this force can be written as the derivative of a potential function. On the other hand, there exist compelling specific arguments t

Michael Vogel

Molecular dynamics simulations are performed to study the lithium jumps in LiPO3 glass. In particular, we calculate higher-order correlation functions that probe the positions of single lithium ions at several times. Three-time correlation functions show that the non-exponential relaxation of the lithium ions results from both correlated back-and-forth jumps

A. Delin, E. Tosatti, R. A. Weht

We have investigated Pd nanowires theoretically, and found that, unlike either metallic or free atomic Pd, they exhibit Hund's rule magnetism. In long, monoatomic wires, we find a spin moment of 0.7 Bohr magnetons per atom, whereas for short, monoatomic wires between bulk leads, the predicted moment is about 0.3 Bohr magnetons per wire atom. In contrast,

L. Moriconi, Ana L. C. Pereira, P. A. Schulz

Scaling properties of the quantum Hall metal-insulator transition are severely affected by finite size effects in small systems. Surprisingly, despite the narrow spatial range where probability structure functions exhibit multifractal scaling, we clearly verify the existence of extended self-similarity -- a hidden infrared scaling phenomenon related to the p

Srutarshi Pradhan, Pinaki Choudhuri, Bikas K. Chakrabarti

The two-fractal overlap model of earthquake shows that the contact area distribution of two fractal surfaces follows power law decay in many cases and this agrees with the Guttenberg-Richter power law. Here, we attempt to predict the large events (earthquakes) in this model through the overlap time-series analysis. Taking only the Cantor sets, the overlap si

Srutarshi Pradhan, Bikas K. Chakrabarti

We study the failure properties of fiber bundles when continuous rupture goes on due to the application of external load on the bundles. We take the two extreme models: equal load sharing model (democratic fiber bundles) and local load sharing model. The strength of the fibers are assumed to be distributed randomly within a finite interval. The democratic fi

Chi-Yong Lin, Paolo Tommasini, E. J. V. de Passos, M. S. Hussein

As it was proposed and recently verified experimentally, the mechanism of Feshbach resonance in a condensate can create a second condensate component of molecules that coexists with the atomic condensate. In this work we investigate signatures of the presence of the molecular condensate through the equilibrium properties and collective excitations of the hyb

Raluca A. Trasca, M. Mercedes Calbi, Milton W. Cole, Jose L. Riccardo

A lattice gas model of adsorption inside cylindrical pores is evaluated with Monte Carlo simulations. The model incorporates two kinds of site: (a line of) ``axial'' sites and surrounding ``cylindrical shell'' sites, in ratio 1:7. The adsorption isotherms are calculated in either the grand canonical or canonical ensembles. At low temperature,

Jun-ichiro Kishine, Tadeusz Luty, Kenji Yonemitsu

To elucidate a novel pressure-temperature phase diagram of the quasi-one-dimensional mixed-stack charge-transfer (CT) complex TTF-CA, we study the quasi-one-dimensional spin-1 Blume-Emery-Griffith (BEG) model. In addition to the local charge transfer energy and the inter-stack polar (dipole-dipole) interaction, we take account of the inter-stack electrostric

Mahuya Chakrabarti, A. Sarkar, S. Chattapadhayay, D. Sanyal

The temperature dependent (30 K to 300 K) Doppler broadening of the positron annihilated g-radiation (DBPAR) measurement has been carried out on single crystalline Bi-2212 high Tc superconducting sample along two different crystallographic orientations. It has been observed that throughout the temperature range the electron momentum distribution has a relati

S. M. Badalyan, F. M. Peeters

We have studied a finite two-dimensional electron system exposed to a normal nonhomogeneous magnetic field of a chess configuration. Using the conformal mapping method we obtain an exact analytical solution for the electric field distribution in terms of the Jacobi functions. The obtained formula is exploited to calculate the physical quantities of interest:

H. Sakaguchi

Statistical properties of the noisy Burgers and KdV-Burgers equations are numerically studied. It is found that shock-like structures appear in the time-averaged patterns for the case of stepwise fixed boundary conditions. Our results show that the shock structure for the noisy KdV-Burgers equation has an oscillating tail, even for the time averaged pattern.

C. M. Savage, J. Ruostekoski

We investigate a radial spin hedgehog, analogous to the Dirac monopole, in an optically trapped atomic spin-1 Bose-Einstein condensate. By joining together a monopole-antimonopole pair, we may form a vortex line with free ends. We numerically simulate the three-dimensional dynamics and imaginary time relaxation of these structures to nonsingular textures and

Sumithra Sankararaman, Gautam I. Menon, P. B. Sunil Kumar

We propose and study a hydrodynamic model for pattern formation in mixtures of molecular motors and microtubules. The steady state patterns we obtain in different regimes of parameter space include arrangements of vortices and asters separately as well as aster-vortex mixtures and fully disordered states. Such stable steady states are observed in experiments

S. Choi, O. Berman, V. Chernyak, S. Mukamel

The second order response functions and susceptibilities of finite temperature Bose-Einstein Condensates (BEC) in a one dimensional harmonic trap driven by an external field that couples to the particle density are calculated by solving the time-dependent Hartree-Fock-Bogoliubov (TDHFB) equations. These provide additional insight into BEC dynamics, beyond th

David S. Smith, John Scalo, J. Craig Wheeler

(Abridged) We show that sizeable fractions of incident ionizing radiation from stochastic astrophysical sources can be redistributed to biologically and chemically important UV wavelengths, a significant fraction of which can reach the surface. This redistribution is mediated by secondary electrons, resulting from Compton scattering and X-ray photoabsorption

S. K. Patel, C. Kouveliotou, A. Tennant, P. M. Woods

The new transient IGR 16358-4726 was discovered on 2003 March 19 with INTEGRAL. We detected the source serendipitously during our 2003 March 24 observation of SGR 1627-41 with the Chandra X-ray Observatory at the 1.7 x 10^{-10} ergs s^{-1} cm^{-2} flux level (2-10 keV) with a very high absorption column (N_H=3.3(1) x 10^{23} cm^{-2}) and a hard power law spe

W. D. Watson, H. W. Wyld

Calculations are performed for the spectral line profiles and images of astrophysical maser radiation that emerges from isolated spheres and thin disks viewed edge-on. In contrast to previous investigations where various approximations are made, the full equations are solved here for the frequency-dependent radiative transport that includes the thermal motio

M. M. Hanson

New optical MK classification spectra have been obtained for 14 OB star candidates identified by Comeron et al. (2002) and presumed to be possible members of the Cyg OB2 cluster. All 14 candidate OB stars observed are indeed early-type stars, strongly suggesting the remaining 31 candidates identified by Comeron et al. are also early-type stars. However, as m

Judith Cohen

About 45% of the point sources detected in the 2 Ms Chandra exposure of the HDF-N can be matched with moderately bright galaxies with z<1.4 that have been studied by the Caltech Faint Galaxy Redshift Survey. Although the optical spectra of these galaxies appear normal, based on their X-ray properties ~20% of them appear to contain weak AGNs. More than 90% of

Ingrid H. Stairs

Pulsars of very different types - isolated objects, and binaries with short- and long-period orbits, white-dwarf and neutron-star companions - provide the means to test both the predictions of general relativity and the viability of alternate theories of gravity. This article presents an overview of pulsars, then discusses the current status and future prosp

I. De Mitri, G. Marsella, F. Salamida

Intrinsic differences in the processes involved in the development of electromagnetic and hadronic showers in the atmosphere have been evidenced by means of a careful analysis of the event image given by the ARGO-YBJ detector. The images have been analyzed at different length scales and their multifractal nature has been studied. The use of the multiscale ap

D. Marik, K. petrovay

We present a model for the lower overshoot layer of the Sun, based on the realistic solar stratification, without the use of a &#34;mixing-length&#34; parameter, by solving the system of Reynolds momentum equations using the closure formalism of Canuto & Dubovikov (1997, 1998). A fixed value of velocity anisotropy is assumed, and the local convection model i

Philip Massey

The galaxies of the Local Group that are currently forming stars can serve as our laboratories for understanding star formation and the evolution of massive stars. In this talk I will summarize what I think we&#39;ve learned about these topics over the past few decades of research, and briefly mention what I think needs to happen next.

Michael Rowan-Robinson

Photometric redshifts are studied with a template approach using data from HDF-N and -S . The problem of aliasing in photometric redshift estimates is investigated in some detail and found not to be a significant problem if at least four photometric bands are available. The performance of the approach presented here appears to exceed that of others in the li

Marco Limongi, Alessandro Chieffi, Piercarlo Bonifacio

We show that the &#34;puzzling&#34; chemical composition observed in the extremely metal poor star HE0107-5240 may be naturally explained by the concurrent pollution of at least two supernovae. In the simplest possible model a supernova of quite low mass (~15 Msun), underwent a &#34;normal&#34; explosion and ejected ~0.06 Msun of 56Ni while a second one was

J. Rodriguez, M. Del Santo, F. Lebrun, G. Belanger

We report on INTEGRAL/IBIS observations of the Vela region during a Galactic Plane Scan (hereafter GPS) presenting the IBIS in-flight performances during these operations. Among all the known sources in the field of view we clearly detect 4U 0836-429, Vela X-1, Cen X-3, GX 301-2, 1E 1145.1-6141, and H0918-549 in the 20-40 keV energy range. Only Vela X-1 and

Jay D. Salmonson

Herein I present numerical calculations of lightcurves of homogeneous and structured afterglows with various lateral expansion rates as seen from any vantage point. Such calculations allow for direct simulation of observable quantities for complex afterglows with arbitrary energy distributions and lateral expansion paradigms. A simple, causal model is sugges

G. Malaguti, A. Bazzano, V. Beckmann, A. J. Bird

In the late afternoon of November 25, 2002 a gamma-ray burst (GRB) was detected in the partially coded field of view (about 7.3 deg from the centre) of the imager IBIS on board the INTEGRAL satellite. The instruments on-board INTEGRAL allowed, for the first time, the observation of the prompt gamma-ray emission over a broad energy band from 15 to 500 keV. GR

Ignazio Bombaci

In a very recent paper Shaposhnikov et al. (ApJ 593, 2003, L35) have extracted very tight constraints on the radius and the mass for the compact star in the low mass X-ray binary 4U~1728-34, from the analysis of a set of Type I X-ray bursts from this source. In the present letter, we perform a systematic comparison between the mass-radius (MR) relation given

A. M. Swinbank, J. Smith, R. G. Bower, A. Bunker

In this letter, we exploit the gravitational potential of the rich cluster A2218 as a magnifying glass. We demonstrate that the magnification due to the cluster allows us to observe distant background galaxies at a comparable level of detail to galaxies at z~0.1. Using the GMOS Integral Field Unit on Gemini North we observed the spatially-resolved [OII](3727

A. Gal-Yam, D. Maoz, K. Sharon, F. Prada

We present the results of several surveys for supernovae (SNe) in galaxy clusters. SNe discovered in deep, archival HST images were used to measure the cluster SN Ia rate to z=1. A search for SNe in nearby (0.06 < z < 0.2) Abell galaxy clusters yielded 15 SNe, 12 of which were spectroscopically confirmed. Of these, 7 are cluster SNe Ia, which we will use to

Naoki Itoh, Satoshi Nozawa

We present an accurate numerical table for the relativistic corrections to the thermal Sunyaev-Zeldovich effect for clusters of galaxies. The numerical results for the relativistic corrections have been obtained by numerical integration of the collision term of the Boltzmann equation. The numerical table is provided for the ranges 0.002 <= theta_e <= 0.100 a

Y. Osaki

A new method for analyzing complex superhump light curves for the 2001 outburst of WZ Sagittae is proposed. The complexity arises because intrinsically time-varying and non-axisymmetric distributions of superhump light sources are coupled with the aspect effects around the binary orbital phase because of its high orbital inclination. The new method can disen

Youichi Ohyama, Michitoshi Yoshida, Tadafumi Takata

We report on our new analysis of the spatial and kinematical distribution of warm and cold molecular gas in NGC 6240, which was undertaken to explore the origin of its unusually luminous H$_2$ emission. By comparing three-dimensional emission-line data (in space and velocity) of CO (J=2-1) in the radio and H$_2$ in the near infrared, we are able to study the

Daniel B. Nestor, Sandhya M. Rao, David A. Turnshek, Daniel Vanden Berk

Using Sloan Digital Sky Survey (SDSS) early data release spectra, we have identified 370 MgII absorption systems with MgII 2796 rest equivalent widths >= 1A and redshifts z=0.9-2.2. From our previous and ongoing HST UV spectroscopic studies, we estimate that the mean neutral hydrogen column density of a system selected in this manner is N(HI) = 3.6 +/- 1.3 x

David L. Mobley, Daniel L. Cox, Rajiv R. P. Singh, Michael W. Maddox

Inspired by recent suggestions that the Alzheimer&#39;s amyloid beta peptide (A beta) can insert into cell membranes and form harmful ion channels, we model insertion of the 40 and 42 residue forms of the peptide into cell membranes using a Monte Carlo code which is specific at the amino acid level. We examine insertion of the regular A-beta peptide as well

Herman J. Mosquera Cuesta, Jose M. Salim

Currently is argued that the best method of determining the neutron star (NS) fundamental properties is by measuring the {\it gravitational redshift} ($z$) of spectral lines produced in the star photosphere. Measurement of $z$ at the star surface provides a unique insight on the NS mass-to-radius relation and thus on its equation of state (EoS), which reflec

Avi M. Mandell, Steinn Sigurdsson

The presence of ``Hot Jupiters&#39;&#39;, Jovian mass planets with very short orbital periods orbiting nearby main sequence stars, has been proposed to be primarily due to the orbital migration of planets formed in orbits initially much further from the parent star. The migration of giant planets would have profound effects on the evolution of inner terrestr

Bernhard G. Bodmann

A lower bound for the Wehrl entropy of a single quantum spin is derived. The high-spin asymptotics of this bound coincides with Lieb&#39;s conjecture up to, but not including, terms of first and higher order in the inverse spin quantum number. The result presented here may be seen as complementary to the verification of the conjecture in cases of lowest spin

Bastien Aracil, Patrick Petitjean, Christophe Pichon, Jacqueline Bergeron

We use high spectral resolution (R=45000) and high signal-to-noise ratio (S/N \~ 35-70 per pixel) spectra of 19 high-redshift (2.1<z_em<3.2) quasars to investigate the metal content of the low-density intergalactic medium using pixel-by-pixel procedures. This high quality homogeneous survey gives the possibility to statistically search for metals at HI optic

Jeffrey D. Crane, Steven R. Majewski, Helio J. Rocha-Pinto, Peter M. Frinchaboy

To determine the nature of the recently discovered, ring-like stellar structure at the Galactic anticenter, we have collected spectra of a set of presumed constituent M giants selected from the 2MASS point source catalog. Radial velocities have been obtained for stars spanning ~100 degrees, exhibiting a trend in velocity with Galactic longitude and an estima

M. M. Islam, R. J. Luddy, A. V. Prokudin

High energy elastic pp differential cross section at LHC at the c.m. energy 14 TeV is predicted using the asymptotic behavior of sigma-tot(s) and rho(s), and the measured pbar-p differential cross section at sqrt{s}=546 GeV. The phenomenological investigation has progressively led to an effective field theory model that describes the nucleon as a chiral bag

T. S. Nyawelo, J. W. van Holten, S. Groot Nibbelink

We propose an alternative for the Clebsch decomposition of currents in fluid mechanics, in terms of complex potentials taking values in a Kahler manifold. We reformulate classical relativistic fluid mechanics in terms of these complex potentials and rederive the existence of an infinite set of conserved currents. We perform a canonical analysis to find the e

Marco Matone

We study the covariance properties of the equations satisfied by the generating functions of the chiral operators R and T of supersymmetric SO(N)/Sp(N) theories with symmetric/antisymmetric tensors. It turns out that T is an affine connection. As such it cannot be integrated along cycles on Riemann surfaces. This explains the discrepancies observed by Kraus

Oleg Lunin, Soo-Jong Rey

Non(anti)commutative gauge theories are supersymmetric Yang-Mills and matter system defined on a deformed superspace whose coordinates obey non(anti)commutative algebra. We prove that these theories in four dimensions with N=1/2 supersymmetry are renormalizable to all orders in perturbation theory. Our proof is based on operator analysis and symmetry argumen

David Maxwell

We construct asymptotically Euclidean solutions of the vacuum Einstein constraint equations with an apparent horizon boundary condition. Specifically, we give sufficient conditions for the constant mean curvature conformal method to generate such solutions. The method of proof is based on the barrier method used by Isenberg for compact manifolds without boun

Chao-Shang Huang, Shou-hua Zhu

The mixing induced time dependent CP asymmetry, direct CP asymmetry, and branching ratio in $B \to ΦK_S$ in a model III 2HDM are calculated, in particular, neutral Higgs boson contributions are included. It is shown that satisfying all the relevant experimental constraints, for time dependent CP asymmetry $S_{ϕK}$ the model III can agree with the present dat

The CDF Collaboration, D. Acosta

We report on measurements of differential cross sections d sigma/d p_t for prompt charm meson production in p anti-p collisions at s**(1/2) = 1.96 TeV using 5.8 +/- 0.3 pb-1 of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm

A. Andreanov, F. Barbieri, O. C. Martin

The ground-state energy E_0 of a spin glass is an example of an extreme statistic. We consider the large deviations of this energy for a variety of models when the number of spins N goes to infinity. In most cases, the behavior can be understood qualitatively, in particular with the help of semi-analytical results for hierarchical lattices. Particular attent

A. Rebhan, P. van Nieuwenhuizen, R. Wimmer

The one-loop quantum corrections to the mass and central charge of the N=2 vortex in 2+1 dimensions are determined using supersymmetry-preserving dimensional regularization by dimensional reduction of the corresponding N=1 model with Fayet-Iliopoulos term in 3+1 dimensions. Both the mass and the central charge turn out to have nonvanishing one-loop correctio

Jean-Luc Thiffeault, Charles R. Doering, John D. Gibbon

An upper bound on the mixing efficiency is derived for a passive scalar under the influence of advection and diffusion with a body source. For a given stirring velocity field, the mixing efficiency is measured in terms of an equivalent diffusivity, which is the molecular diffusivity that would be required to achieve the same level of fluctuations in the scal

Dimitra Karabali, V. P. Nair

We show that the effective action for the edge excitations of a quantum Hall droplet of fermions in higher dimensions is generically given by a chiral bosonic action. We explicitly analyze the quantum Hall effect on complex projective spaces ${\bf CP}^k$ with a U(1) background magnetic field. The edge excitations are described by abelian bosonic fields on $S

Krzysztof Gozdziewski, Maciej Konacki

The new 2-planetary system around HD169830 has been announced during the XIX-th IAP Colloquium &#34;Extrasolar Planets: Today & Tomorrow&#34; (Paris, June 30 - July 4, 2003) by the Geneva Extrasolar Planet Search team. We study the orbital dynamics of this system in the framework of the $N$-body problem. The analysis of its orbital stability is performed usi

Lubomira G. Softova

We study Poincaré problem for a linear uniformly parabolic operator $¶$ in a cylinder $Q=Ω\times (0,T).$ The boundary operator $\B$ is defined by an oblique derivative with respect to a tangential vector field $ł$ defined on the lateral boundary $S.$ The coefficients of $¶$ are supposed to be $VMO$ away from the set of tangency $E$ and to possess higher regu

G. A. Kells, J. Twamley, D. M. Heffernan

We propose an efficient procedure for numerically evolving the Delta Kicked Harmonic Oscillator. The method allows for longer and more accurate simulations of the system as well as a simple procedure for calculating the systems Floquet eigenstates and quasi-energies. The method is used to examine the dynamical behaviour of the system in cases where the ratio

M. R. Dennis

Nodal lines (phase singularities, optical vortices) are the generic interference fringes of complex scalar waves. Here, an exact complex solution of the time independent wave equation (Helmholtz equation) is considered, possessing nodal lines which are braided in the form of a borromean, or pig-tail braid. The braid field is a superposition of counterpropaga

M. Berkooz, B. Pioline

Arguably the simplest model of a cosmological singularity in string theory, the Lorentzian orbifold $\Real^{1,1}/boost$ is known to lead to severe divergences in scattering amplitudes of untwisted states, indicating a large backreaction toward the singularity. In this work we take a first step in investigating whether condensation of twisted states may remed

K. Ulker

The extended BRST cohomology of N=2 super Yang-Mills theory is discussed in the framework of Algebraic Renormalization. In particular, N=2 supersymmetric descent equations are derived from the cohomological analysis of linearized Slavnov-Taylor operator $\B$. It is then shown that both off- and on-shell N=2 super Yang-Mills actions are related to a lower-dim

P. Grassberger

We present a detailed derivation of some estimators of Shannon entropy for discrete distributions. They hold for finite samples of N points distributed into M &#34;boxes&#34;, with N and M -> oo, but N/M < oo. In the high sampling regime (<< 1 points in each box) they have exponentially small biases. In the low sampling regime the errors increase but are sti

Nuno D. Antunes, Levon Pogosian, Tanmay Vachaspati

We study the formation of domain walls in a phase transition in which an S_5\times Z_2 symmetry is spontaneously broken to S_3\times S_2. In one compact spatial dimension we observe the formation of a stable domain wall lattice. In two spatial dimensions we find that the walls form a network with junctions, there being six walls to every junction. The networ

Pasquale Calabrese, Pietro Parruccini, Andrea Pelissetto, Ettore Vicari

We study the crossover behaviors that can be observed in the high-temperature phase of three-dimensional dilute spin systems, using a field-theoretical approach. In particular, for randomly dilute Ising systems we consider the Gaussian-to-random and the pure-Ising-to-random crossover, determining the corresponding crossover functions for the magnetic suscept

A. Niegawa

We construct perturbative frameworks for studying nonequilibrium spin-polarized quark matter. We employ the closed-time-path formalism and use the gradient approximation in the derivative expansion. After constructing self-energy-part resummed quark and gluon propagators, we formulate two kind of mutually equivalent perturbative frameworks: The first one is

Lasse Rempe

We answer a question of Schleicher by showing that, for an exponential map with nonescaping singular value, every periodic ray lands. This is an analog of a theorem of Douady and Hubbard concerning polynomials. We also prove a partial converse: there are periodic external rays landing at all periodic points, with the exception of at most one periodic orbit.