May 2003 arXiv papers — page 23

Chunhui Lai

In 1975, P. Erdös proposed the problem of determining the maximum number $f(n)$ of edges in a graph of $n$ vertices in which any two cycles are of different lengths. In this paper, it is proved that $$f(n)\geq n+36t$$ for $t=1260r+169 (r\geq 1)$ and $n \geq 540t^{2}+{175811/2}t+{7989/2}$. Consequently, $\liminf\sb {n \to \infty} {f(n)-n \over \sqrt n} \geq \

Remke Kloosterman

In this paper it is shown that for every prime p>5 the dimension of the p-torsion in the Tate-Shafarevich group of E/K can be arbitrarily large, where E is an elliptic curve defined over a number field K, with [K:Q] bounded by a constant depending only on p. From this we deduce that the dimension of the p-torsion in the Tate-Shafarevich group of A/Q can be a

Joerg Winkelmann

We characterize Kaehler manifolds with trivial logarithmic tangent bundle (with respect to a divisor D) as a class of certain compatifications of complex semi-tori.

Octav Cornea, Andrew Ranicki

We obtain rigidity and gluing results for the Morse complex of a real-valued Morse function as well as for the Novikov complex of a circle-valued Morse function. A rigidity result is also proved for the Floer complex of a hamiltonian defined on a closed symplectic manifold $(M,ω)$ with $c_{1}|_{π_{2}(M)}=[ω]|_{π_{2}(M)}=0$. The rigidity results for these com

L. Katzarkov, T. Pantev, C. Simpson

In this paper we study the monodromy action on the first Betti and de Rham non-abelian cohomology arising from a family of smooth curves. We describe sufficient conditions for the existence of a Zariski dense monodromy orbit. In particular we show that for a Lefschetz pencil of sufficiently high degree the monodromy action is dense.

John M. Cornwall

We correct an unfortunate error in an earlier work of the author, and show that in center-vortex QCD (gauge group SU(3)) the baryonic area law is the so-called $Y$ law, described by a minimal area with three surfaces spanning the three quark world lines and meeting at a central Steiner line joining the two common meeting points of the world lines. (The earli

Steven Corley

We consider an N=1 SU(N_c) SUSY gauge theory with N_f \geq N_c matter multiplets transforming in the fundamental and antifundamental representations of the gauge group. Using the Konishi anomaly and a non-anomalous conservation law, we derive a system of partial differential equations that determine the low energy effective superpotential as a function of th

C. I. Lazaroiu

This is an exposition of recent progress in the categorical approach to D-brane physics. I discuss the physical underpinnings of the appearance of homotopy categories and triangulated categories of D-branes from a string field theoretic perspective, and with a focus on applications to homological mirror symmetry.

Chanju Kim, Yoonbai Kim, O-Kab Kwon, Chong Oh Lee

In the context of tachyon effective theory coupled to Born-Infeld electromagnetic fields, we obtain all possible singularity-free static flat configurations of codimension one on unstable Dp-branes. Computed tension and string charge density suggest that the obtained kinks are D(p-1) or D(p-1)F1-branes.

Marco Bochicchio

For (planar) closed self-avoiding loops we construct a "holographic" map from the loop equations of large-N QCD_4 to an effective action defined over infinite rank Hitchin bundles. The effective action is constructed densely embedding Hitchin systems into the functional integral of a partially quenched or twisted Eguchi-Kawai model, by means of the r

Dimitri Bourilkov

The experimental errors in current and future hadron colliders are expected to decrease to a level that will challenge the uncertainties in the theoretical calculations. One important component in the prediction uncertainties comes from the Parton Density Functions of the (anti)proton. In this work we develop an interface from the Les Houches Accord Parton D

Dimitri Bourilkov

Virtual effects from a generic description of physics beyond the Standard Model in terms of contact interactions, or from large extra dimensions will modify the observed cross sections for easy to detect final states like lepton or photon pairs, and can be used to probe scales much higher than the center-of-mass energy of the partons initiating the interacti

D. Yu. Ivanov

We report a study of the processes of coherent a pion and a photon diffraction dissociation into two jets. The structure of non-factorizable contributions in these reactions is discussed. We argue that production of hard dijets by real photons can provide direct evidence for chirality violation in hard processes and the first measurement of the magnetic susc

M. Gozdz, Wieslaw A. Kaminski, A. Wodecki

The Minimal Supersymmetric Standard Model with gauge mediated supersymmetry breaking and trilinear R-parity violation is applied to the description of neutrinoless double beta decay. A detailed study of limits on the parameter space coming from the B to (X,gamma) processes by using the recent CLEO results is performed. The importance of two-nucleon and pion-

Ch. P. Schuetz

The DIRAC experiment at CERN aims to measure the lifetime of the pionium atom ($A_{2π}$), a $π^+π^-$ bound state with an accuracy of 10%. The experimental setup consists of a high precision magnetic double arm spectrometer, located at the high intensity proton beam of the CERN Proton Synchrotron. This measurement will provide - in a model independent way - t

W. R. B. de Araújo, T. Frederico, M. Beyer, H. J. Weber

The neutron charge radius is studied within a light-front model with different spin coupling schemes and wave functions. The cancellation of the contributions from the Foldy term and Dirac form factor to the neutron charge form factor is verified for large nucleon sizes and it is independent of the detailed form of quark spin coupling and wave function. For

F. del Aguila, M. Perez-Victoria, J. Santiago

In theories with extra dimensions there are generically brane kinetic terms for fields living in the bulk. These modify the masses and wave functions of the Kaluza-Klein expansions, and then the effective four dimensional gauge and Yukawa couplings of the corresponding modes. Here, we discuss some phenomenological consequences of fermion brane kinetic terms,

Nobuhiro Maekawa, Toshifumi Yamashita

We show that the unification of the doublet Higgs in the standard model (SM) and the Higgs to break the grand unified theory (GUT) group stabilizes the sliding singlet mechanism which can solve the doublet-triplet (DT) splitting problem. And we generalize this attractive mechanism to apply it to many unified scenarios. In this paper, we try to build various

Satoru Akiyama, Yasuhiko Futami

In this paper the stability of the hedgehog shape of the chiral soliton is studied for the octet baryon with the SU(3) chiral quark soliton model. The strangeness degrees of freedom are treated by a simplified bound-state approach, which omits the locality of the kaon wave function. The mean field approximation for the flavor rotation is applied to the model

Ulrich Ellwanger, John F. Gunion, Cyril Hugonie, Stefano Moretti

We scan the parameter space of the NMSSM for the observability of a Higgs boson at the LHC with $300 {\rm fb}^{-1}$ integrated luminosity per detector, taking the present LEP constraints into account. We focus on the regions of parameter space for which none of the usually considered LHC detection modes are viable due to the fact that the only light non-sing

Kingman Cheung

In this talk, we summarize the collider phenomenology and recent experimental results for various models of extra dimensions, including the large extra dimensions (ADD model), warped extra dimensions (Randall-Sundrum model), TeV$^{-1}$-sized extra dimensions with gauge bosons in the bulk, universal extra dimensions, and an 5D SU(5) SUSY GUT model in AdS spac

T. V. Shishkina, V. V. Makarenko

The exclusive reaction $ γγ\to f \bar{f} γ$ is considered as the possible calibration process on the linear photon collider. We analyse the energy spectrum and total cross section dependence on the detector parameters at various initial beam helicities.

FOCUS Collaboration, J. M. Link

Studies of $D{\bar D}$ correlations for a large sample of events containing fully and partially reconstructed pairs of charmed $D$ mesons recorded by the Fermilab photoproduction experiment FOCUS (FNAL-E831) are presented. Correlations between $D$ and ${\bar D}$ mesons are used to study heavy quark production dynamics. We present results for fully and partia

V. Gyurjyan, D. Abbott, G. Heyes, E. Jastrzembski

A control system with the capabilities to combine heteregeneous control systems or processes into a uniform homogeneous environment is discussed. This dynamically extensible system is an example of the software system at the agent level of abstraction. This level of abstraction considers agents as atomic entities that communicate to implement the functionali

H1 Collaboration

Deep-inelastic e^\pm p scattering at high squared momentum transfer Q^2 up to 30000 GeV^2 is used to search for eq contact interactions associated to scales far beyond the HERA centre of mass energy. The neutral current cross section measurements d sigma / d Q^2, corresponding to integrated luminosities of 16.4 pb^-1 of e^- p data and 100.8 pb^-1 of e^+ p da

N. van Remortel

This paper presents an overview of the latest results from the L3 and DELPHI collaborations concerning the measurement of Bose-Einstein correlations between identical bosons coming from different W's in fully hadronic WW decays. Using the same method, L3 sees no indication of any inter-W BEC effect, while DELPHI reports an indication of inter-W BEC betwe

John Quiroga Hurtado

In this paper a quantum N = 4 super Yang-Mills theory perturbed by dilaton-coupled scalars, is considered. The induced effective action for such a theory is calculated on a dilaton-gravitational background using the conformal anomaly found via AdS/CFT correspondence. Considering such an effective action (using the large N method) as a quantum correction to t

Abhik Kumar Sanyal

Canonical quantization of the Brane-World effective action presented by Kanno and Soda containing higher order curvature invariant terms, has been performed. It requires introduction of an auxiliary variable. As observed in a series of publications by Sanyal and Modak, here again we infer that properly chosen auxiliary variable leads to a Schrodinger like eq

Roberto Bergamini, Stefano Viaggiu

We present a simple technique for generating new solutions of Einstein's equations using such function transformations that leave the field equations in the Ernst form. In this context we recover all the known covariant transformations of Ernst equations and we find the role of the analytic ones. Finally we obtain a new asymptotically flat solution start

Ming-Yang Chen, Hsueh-I. Lu, Hsu-Chun Yen

A coloring of a complete bipartite graph is shuffle-preserved if it is the case that assigning a color $c$ to edges $(u, v)$ and $(u', v')$ enforces the same color assignment for edges $(u, v')$ and $(u',v)$. (In words, the induced subgraph with respect to color $c$ is complete.) In this paper, we investigate a variant of the Ramsey problem f

Hirokazu Tsunetsugu, Yukitoshi Motome

We propose a scenario for the two phase transitions in $A$V$_2$O$_4$ ($A$=Zn, Mg, Cd), based on an effective spin-orbital model on the pyrochlore lattice. At high temperatures, spin correlations are strongly frustrated due to the lattice structure, and the transition at $\sim$50 [K] is an orbital order, supported by Jahn-Teller lattice distortion. This orbit

Marco Cozzini, Sandro Stringari

The dynamic behavior of a Fermi gas confined in a deformed trap rotating at low angular velocity is investigated in the framework of hydrodynamic theory. The differences exhibited by a normal gas in the collisional regime and a superfluid are discussed. Special emphasis is given to the collective oscillations excited when the deformation of the rotating trap

Chao Huan, Xiaoyu Yang, D. Candela, R. W. Mair

A three-dimensional granular system fluidized by vertical container vibrations was studied using pulsed field gradient (PFG) NMR coupled with one-dimensional magnetic resonance imaging (MRI). The system consisted of mustard seeds vibrated vertically at 50 Hz, and the number of layers N_ell <= 4 was sufficiently low to achieve a nearly time-independent granul

Craig J. Fennie, Karin M. Rabe

We have investigated the structural and dielectric properties of Sr$_{2}$TiO$_{4}$,the first member of the Sr$_{n+1}$Ti$_{n}$O$_{3n+1}$ Ruddlesden-Popper series, within density functional theory. Motivated by recent work in which thin films of Sr$_{2}$TiO$_{4}$ were grown by molecular beam epitaxy (MBE) on SrTiO$_{3}$ substrates, the in-plane lattice paramet

T. G. Sokolovska, M. E. Cates, R. O. Sokolovskii

A simple model is proposed for nematogenic molecules that favor perpendicular orientations as well as parallel ones. (Charged rods, for example, show this antagonistic tendency.) When a small disorienting field is applied along $z$, a low density phase $N_-$ of nematic order parameter $S_z<0$ coexists with a dense biaxial nematic $N_b$. (At zero field, $N_-$

H. Seppä, J. Hassel

We introduce a new mesoscopic transistor, which consists of a superconducting island connected to superconducting and normal electrodes via two mesoscopic tunnel junctions. Furthermore, the island is being charged through a resistor. The interplay between Bloch oscillations, single-electron effects and ohmic current leads to a device having a high current ga

Mingfeng He, Hongbo Ruan, Changliang Yu

We presented a predator-prey lattice model containing moveable wolves and sheep, which are characterized by Penna double bit strings. Sexual reproduction and child-care strategies are considered. To implement this model in an efficient way, we build a fully parallel Cellular Automata based on a new definition of the neighborhood. We show the roles played by

A. Urbina, I. Echeverría, A. Pérez-Garrido, A. Díaz-Sánchez

We have prepared solutions of multiwalled carbon nanotubes in Aroclor 1254, a mixture of polychlorinated biphenyls. The solutions are stable at room temperature. Transport measurements were performed using a scanning--tunneling probe on a sample prepared by spin--coating of the solution on gold substrates. Conductance steps were clearly seen. An histogram of

M. M. Glazov, E. L. Ivchenko, M. A. Brand, O. Z. Karimov

The D&#39;yakonov-Perel&#39; spin relaxation mechanism in n-doped GaAs/AlGaAs quantum wells (QWs) has been studied both theoretically and experimentally. The temperature dependence of the spin relaxation time has been calculated for arbitrary degeneracy of the 2D electron gas. The comparison between theory and experiment shows that, in high-mobility n-doped

A. Fessant, J. Gieraltowski, C. Tannous, R. Valenzuela

A novel broad-band measurement method of the MI in thin films and ribbons is presented. It is based on the automated measurement of the reflection coefficient of a cell loaded with the sample. Illustrative results obtained with a permalloy multilayer thin film are presented and discussed.

Dingping Li, Baruch Rosenstein

The precise measurements of vortex melting point towards a need to develop a quantitative theoretical description of thermal fluctuations in vortex matter. To tackle the difficult problem of melting, the description of both the solid and the liquid phase should reach the precision level well below 0.1%. Such a theory in the framework of the Ginzburg - Landau

A. Sharoni, G. Leibovitch, A. Kohen, R. Beck

Tunneling spectroscopy of epitaxial (100) oriented \chem{YBa_2Cu_3O_{7-δ}} films was performed using an STM at 4.2 K. On atomically smooth areas, tunneling spectra revealing clear U-shaped gaps with relatively low zero bias conductance were measured. These spectra can be well fitted to the tunneling theory into a d-wave superconductor only when introducing a

Dingping Li, Baruch Rosenstein

A metastable homogeneous state exists down to zero temperature in systems of repelling objects. Zero &#39;&#39;fluctuation temperature&#39;&#39; liquid state therefore serves as a (pseudo) &#39;&#39;fixed point&#39;&#39; controlling the properties of vortex liquid below and even around melting point. There exists Madelung constant for the liquid in the limit

G. K. Perkins, Y. Bugoslavsky, A . D. Caplin, J. Moore

We present magnetisation data on crystalline and polycrystalline MgB2 before and after irradiation with ~1MeV protons. In the virgin crystal the critical current density is below our noise floor of 103A/cm2 over most of the field range. However, after irradiation a peak occurs in the current density as a function of applied magnetic field as the upper critic

Robert Urbanczik

An unsupervised learning procedure based on maximizing the mutual information between the outputs of two networks receiving different but statistically dependent inputs is analyzed (Becker and Hinton, Nature, 355, 92, 161). For a generic data model, I show that in the large sample limit the structure in the data is recognized by mutual information maximizati

D. D. Shivagan, P. M. Shirage, S. H. Pawar

Metal/superconductor/semiconductor (Ag/HgBaCaCuO/CdSe) heterostructures have been successfully fabricated using pulse-electrodeposition technique. The electrochemical parameters are optimized and diffusion free growth of CdSe onto Ag/HgBaCaCuO was obtained by employing under-potential deposition and by studying nucleation and growth mechanism during depositi

J. Gieraltowski, A. Fessant, R. Valenzuela, C. Tannous

Giant magneto impedance (GMI) effect for as-cast Vitrovac$^{\textrm{\scriptsize\textregistered}}$ amorphous ribbons (Vacuumschmelze, Germany) in two configurations (parallel and normal to the ribbon axis) is studied over the frequency range [0.3-400 MHz] and under static magnetic fields -160 Oe $< H_{dc} < $+160 Oe. A variety of peak features and GMI ratio v

B. Jackson, E. Zaremba

We study Landau damping in dilute Bose-Einstein condensed gases in both spherical and prolate ellipsoidal harmonic traps. We solve the Bogoliubov equations for the mode spectrum in both of these cases, and calculate the damping by summing over transitions between excited quasiparticle states. The results for the spherical case are compared to those obtained

W. Belzig, P. Samuelsson

We study the full counting statistics of heterostructures consisting of normal metal parts connected to a superconducting terminal. Assuming that coherent superconducting correlations are suppressed in the normal metals we show, using Keldysh-Nambu Green&#39;s functions, that the system can be mapped onto a purely normal system with twice the number of eleme

Alexander Altland, Leonid I. Glazman, Alex Kamenev

We consider thermodynamic and transport properties of a long granular array with strongly connected grains (inter-grain conductance g>>1.) We find that the system exhibits activated behavior of conductance and thermodynamic density of states ~exp(-T*/T) where the gap, T*, is parametrically larger than the energy at which conventional perturbation theory brea

V. Gurarie, A. M. Tsvelik

We consider a one-dimensional Josephson junction array, in the regime where the junction charging energy is much greater than the charging energy of the superconducting islands. In this regime we critically reexamine the continuum limit description and establish the relationship between parameters of the array and the ones of the resulting sine-Gordon model.

Manabu Takahashi, Jun-ichi Igarashi

We theoretically investigate the origin of the x-ray magnetic circular dichroism (XMCD) spectra at the K edges of Mn and Ga in the ferromagnetic phase of Mn3GaC on the basis of an ab initio calculation. Taking account of the spin-orbit interaction in the LDA scheme, we obtain the XMCD spectra in excellent agreement with the recent experiment. We have analyze

Masahito Ueda, Hiroki Saito

We present a consistent picture of the recent JILA experiments on the collapse of a Bose-Einstein condensate (BEC) [E. A. Donley, et al., Nature 412, 295 (2001)] based on a generalized Gross-Pitaevskii equation that incorporates the effect of a three-body loss. The questions we address in this paper are: (1) Why does a BEC survive, albeit partially, after th

Hiro-Sato Niwa

There has been some confusion concerning the animal group-size: an exponential distribution was deduced by maximizing the entropy; lognormal distributions were practically used; a power-law decay with exponent {3/2} was proposed in physical analogy to aerosol condensation. Here I show that the animal group-size distribution follows a power-law decay with exp

Olga Kuksenok, David Jasnow, Julia Yeomans, Anna C. Balazs

Simulations show that when a phase-separated binary AB fluid is driven to flow past chemically patterned substrates in a microchannel, the fluid exhibits unique morphological instabilities. For the pattern studied, these instabilities give rise to the simultaneous, periodic formation of monodisperse droplets of A-in-B and B-in-A. The system bifurcates betwee

Lixin He, David Vanderbilt

We have investigated the interaction of oxygen vacancies and 180-degree domain walls in tetragonal PbTiO3 using density-functional theory. Our calculations indicate that the vacancies do have a lower formation energy in the domain wall than in the bulk, thereby confirming the tendency of these defects to migrate to, and pin, the domain walls. The pinning ene

Xin Zhou, Mitsumasa Iwamoto

Heat conduction in one-dimensional (1D) systems is studied based on an analytical S-matrix method, which is developed in the mesoscopic electronic transport theory and molecular dynamic (MD) simulations. It is found that heat conduction in these systems is related to spatial correlation of particle motions. Randomizations of scatterers is found to break the

Zhongqing Wu, Xuanjia Zhang

The effect of the lattice periodic potential on superconductivity which was ignored by BCS theory has been investigated. According to the effective mass approximation of band theory, the effect of lattice periodic potential can be embodied in the effective mass of the Ginzburg-Landau (GL) equations. The effective mass has s special property. It can be negati

S. Temporin, S. Ciroi, P. Rafanelli, M. Radovich

In the context of the connection among galaxy-galaxy interaction, starbursts and nuclear activity, we present and discuss a quantitative morphological analysis based on BVR images and a detailed spectroscopic investigation of two interacting galaxies, the Seyfert 2 Tol1238-364 (IC 3639) and its companion ESO381-G009, forming a triple system with ESO381-G006.

Michael T. Busha, Fred C. Adams, Risa H. Wechsler, August E. Evrard

Current cosmological data indicate that our universe contains a substantial component of dark vacuum energy that is driving the cosmos to accelerate. We examine the immediate and longer term consequences of this dark energy (assumed here to have a constant density). Using analytic calculations and supporting numerical simulations, we present criteria for tes

Evgueni Gouchtchine, Thomas P. McCauley, Yuri Musienko, Thomas C. Paul

We report progress on applying technologies developed for LHC-era experiments to cosmic ray detection, using scintillating tiles with embedded wavelength-shifting fibers and avalanche photodiode readouts as parts of a robust, inexpensive cosmic air shower detector. We are planning to deploy such detectors in high schools as part of an outreach effort able to

F. Kemper, R. Stark, K. Justtanont, A. de Koter

We present submillimeter observations of rotational transitions of carbon monoxide from J = 2 -> 1 up to 7 -> 6 for a sample of Asymptotic Giant Branch stars and red supergiants. It is the first time that the high transitions J = 6 -> 5 and 7 -> 6 are included in such a study. With line radiative transfer calculations, we aim to determine the mass-loss histo

Carlos Hojvat, Thomas P. McCauley, Stephen Reucroft, John D. Swain

A numerical likelihood approach to the determination of cosmic ray anisotropies is presented which offers many advantages over other approaches. It allows a wide range of statistically meaningful hypotheses to be compared even when full sky coverage is unavailable, can be readily extended in order to include measurement errors, and makes maximum unbiased use

Felix Mirabel, Irapuan Rodrigues

We show that the black hole in the x-ray binary Cygnus X-1 was formed in situ and did not receive an energetic trigger from a nearby supernova. The progenitor of the black hole had an initial mass greater than 40 solar masses and during the collapse to form the ~10 solar mass black hole of Cygnus X-1, the upper limit for the mass that could have been suddenl

Neta A. Bahcall, Timothy A. McKay, James Annis, Rita Kim

We present a catalog of 799 clusters of galaxies in the redshift range z_est = 0.05 - 0.3 selected from ~400 deg^2 of early SDSS commissioning data along the celestial equator. The catalog is based on merging two independent selection methods -- a color-magnitude red-sequence maxBCG technique (B), and a Hybrid Matched-Filter method (H). The BH catalog includ

Eran O. Ofek, Hans-Walter Rix, Dan Maoz

The redshifts of lens galaxies in known gravitational lens systems probe the volume distribution of lensing mass. Following earlier work by Kochanek, we re-derive the lens redshift probability distribution, allowing for mass and number density evolution of the lensing galaxies, and apply this test to a much enlarged sample of lens systems. From a literature

Eran O. Ofek, Dan Maoz

We have measured the time delay between the two images of the gravitationally lensed quasar HE1104-1805 by combining observations made with the Wise Observatory 1m telescope and published observations of this system by Schechter et al., spanning a total of five years, from 1997 to 2002. Based on a variety of techniques, we find that the best fit time delay i

The IceCube Collaboration, J. Ahrens

We present the results of a Monte-Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies. A complete simulation of the detector and data analysis is used to study the detector&#39;s capability to search for muon neutrinos from sources such as active galaxies and gamma-ray bursts. We study t

I. Pascucci, D. Apai, Th. Henning, C. P. Dullemond

The combination of mid-infrared and recent submm/mm measurements allows us to set up the first comprehensive spectral energy distribution (SED) of the circumstellar material around a young Brown Dwarf. Simple arguments suggest that the dust is distributed in the form of a disk. We compare basic models to explore the disk parameters. The modeling shows that a

N. J. Haigh, M. J. Coe, J. Fabregat

A0535+26 is shown to display quantised IR excess flux states, which are interpreted as the first observational verification of the resonant truncation scheme proposed by Okazaki and Negueruela (2001) for BeXRBs. The simultaneity of X-ray activity with transitions between these states strongly suggests a broad mechanism for outbursts, in which material lost f

A. Finoguenov, A. Burkert, H. Boehringer

Using the guidelines on SN element production provided by XMM-Newton, we summarize the results of ASCA observations on the element abundance in groups and clusters of galaxies. We show that while the metal production in groups could be described by a stellar population with a standard local IMF, clusters of galaxies require a more top-heavy IMF. We attribute

Kim Venn, Eline Tolstoy, Andreas Kaufer, Rolf Peter Kudritzki

Dwarf irregular galaxies appear to have undergone very slow chemical evolution since they have low nebular abundances, but have had ongoing star formation over the past 15 Gyr. They are too distant for red giant abundance analyses to examine the details of their chemical evolution, however the isolated, bright blue supergiants do allow us to determine their

Pijushpani Bhattacharjee, Nayantara Gupta

Gamma Ray Bursts (GRBs) have been proposed as one {\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\gsim10^{20}\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the e

R. de Grijs, P. Anders, N. Bastian, R. Lynds

We use the ages, masses and metallicities of the rich young star cluster systems in the nearby starburst galaxies NGC 3310 and NGC 6745 to derive their cluster formation histories and subsequent evolution. We further expand our analysis of the systematic uncertainties involved in the use of broad-band observations to derive these parameters by examining the

K. Maeda, K. Nomoto

Bipolar explosion models for hypernovae (very energetic supernovae), associated with the black hole formation, are presented. The model features are as follows: (1) Fe-peak elements are ejected at high velocities to reach the surface region, while dense O-rich materials occupy the central region at low velocities. (2) The abundance ratios (Zn, Co)/Fe are enh

K. Maeda, P. A. Mazzali, J. Deng, K. Nomoto

The light curves of &#39;hypernovae&#39;, i.e. very energetic supernovae with $E_{51} \equiv E/10^{51}$ergs $\gsim 5-10$ are characterized at epochs of a few months by a phase of linear decline. Classical, one-dimensional explosion models fail to simultaneously reproduce the light curve near peak and at the linear decline phase. The evolution of these light

Charles H. Lineweaver

I present a pedagogical review of inflation and the cosmic microwave background. I describe how a short period of accelerated expansion can replace the special initial conditions of the standard big bang model. I also describe the development of CMBology: the study of the cosmic microwave background. This cool (3 K) new cosmological tool is an increasingly p

Marieke Postma

We analyse the curvaton scenario in the context of supersymmetry. Supersymmetric theories contain many scalars, and therefore many curvaton candidates. To obtain a scale invariant perturbation spectrum, the curvaton mass should be small during inflation $m \ll H$. This can be achieved by invoking symmetries, which suppress the soft masses and non-renormaliza

L. Van Waerbeke, Y. Mellier

We review all the cosmic shear results obtained so far, with a critical discussion of the present strengths and weaknesses. We discuss the future prospects and the role cosmic shear could play in a precision cosmology era.

Sidney van den Bergh

It is suggested that M31 was created by the early merger, and subsequent violent relaxation, of two or more massive metal-rich ancestral galaxies within the core of the Andromeda subgroup of the Local Group. On the other hand the evolution of the main body of the Galaxy appears to have been dominated by the collapse of a single ancestral object, that subsequ

J. Ponce de Leon

We investigate the cosmological consequences of a brane-world theory which incorporates time variations in the gravitational coupling G and the cosmological term Lambda. We analyze in detail the model where (dG/dt)/G ~ H and Lambda ~ H^2, which seems to be favored by observations. We show that these conditions single out models with flat space sections. We d

A. Jaster

We report Monte Carlo results for the two-dimensional hard disk system in the transition region. Simulations were performed in the NVT ensemble with up to 1024^2 disks. The scaling behaviour of the positional and bond-orientational order parameter as well as the positional correlation length prove the existence of a hexatic phase as predicted by the Kosterli

Ying Liang, Tianxing Ma, Shiping Feng

Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnet are studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in the electronic structure, the qualitative behaviors of the physical properties are the same as in the single layer case. The conductivi

Vadim A. Adamyan, Cristian S. Calude, Boris S. Pavlov

Hypercomputation or super-Turing computation is a ``computation&#39;&#39; that transcends the limit imposed by Turing&#39;s model of computability. The field still faces some basic questions, technical (can we mathematically and/or physically build a hypercomputer?), cognitive (can hypercomputers realize the AI dream?), philosophical (is thinking more than c

S. A. Gurvitz

We study the measurement process by treating classical detectors entirely quantum mechanically. As a generic model we use a point-contact detector coupled to an electron in a quantum dot and tunneling into the continuum. Transition to the classical description and the mechanism of decoherence are investigated. We concentrate on the influence of the measureme

Xingang Wang, Meng Zhan, C. -H. Lai, Ying-Cheng Lai

Strange nonchaotic attractors (SNAs) in noise driven systems are investigated. Before the transition to chaos, due to the effect of noise, a typical trajectory will wander between the periodic attractor and its nearby chaotic saddle in an intermittent way, forms a strange attractor gradually. The existence of SNAs is confirmed by simulation results of variou

Xingang Wang, Meng Zhan, C. -H. Lai, Gang Hu

Different chaos synchronization based encryption schemes are reviewed and compared from the practical point of view. As an efficient cryptanalysis tool for chaos encryption, a proposal based on the Error Function Attack is presented systematically and used to evaluate system security. We define a quantitative measure (Quality Factor) of the effective applica

William Graham

Let V be a rank N vector bundle on a d-dimensional complex projective scheme X; assume that V is equipped with a quadratic form with values in a line bundle L and that S^2 V^* \otimes L is ample. Suppose that the maximum rank of the quadratic form at any point of X is r > 0. The main result of this paper is that if d > N-r, then the locus of points where the

Bhupinder Singh Anand

We give a precise definition of a formal mathematical object as any symbol for an individual constant, predicate letter, or a function letter that can be introduced through definition into a formal mathematical language without inviting inconsistency. We then show: there is an elementary, recursive, number-theoretic relation that is not a formal mathematical

Bhupinder Singh Anand

In an earlier paper, &#34;Omega-inconsistency in Goedel&#39;s formal system: a constructive proof of the Entscheidungsproblem&#34; (math/0206302), I argued that a constructive interpretation of Goedel&#39;s reasoning establishes any formal system of Arithmetic as omega-inconsistent. It follows from this that Goedel&#39;s Theorem VI holds vacuously. In this p

Bhupinder Singh Anand

If we apply an extension of the Deduction meta-Theorem to Goedel&#39;s meta-reasoning of &#34;undecidability&#34;, we can conclude that Goedel&#39;s formal system of Arithmetic is not omega-consistent. If we then take the standard interpretation &#34;(Ax)(F(x)&#34; of the PA-formula [(Ax)F(x)] to mean &#34;There is a general, x-independent, routine to establ

Bhupinder Singh Anand

I review the classical conclusions drawn from Goedel&#39;s meta-reasoning establishing an undecidable proposition GUS in standard PA. I argue that, for any given set of numerical values of its free variables, every recursive arithmetical relation can be expressed in PA by different, but formally equivalent, propositions. This asymmetry yields alternative Rep

A. P. Baeta Scarpelli, H. Belich, J. L. Boldo, L. P. Colatto

The gauge-invariant Chern-Simons-type Lorentz- and CPT-breaking term is here re-assessed and issues like causality, unitarity, spontaneous gauge-symmetry breaking are investigated. Moreover, we obtain a minimal extension of such a system to a supersymmetric environment. We comment on resulting peculiar self-couplings for the gauge sector, as well as on backg

M. R. Setare

The Casimir forces on two parallel plates in conformally flat domain wall background due to conformally coupled massless scalar field satisfying mixed boundary conditions on the plates is investigated. In the general case of mixed boundary conditions formulae are derived for the vacuum expectation values of the energy-momentum tensor and vacuum forces acting

V. M. Red&#39;kov

The known problem of fermion parity is considered on the base of investigating possible linear single-valued representations of spinor coverings of the extended Lorentz group. It is shown that in the frame of this theory does not exist, as separate concepts, P-parity and T-parity for a fermion, instead only some unified concept of (PT)-parity can be determin

E. Nezri

We study the effect of departures from SUSY GUT gaugino universality on the neutralino relic density, and both its direct and neutrino indirect detection. We find that the most interesting models are those with a value of $M_3|_{GUT}$ lower than the universal case.

Chongxing Yue, Lanjun Liu

We study the lepton flavor violating (LFV) processes $l_{i}\longrightarrow l_{j}ν_{l}\barν_{l}$ in the context of the topcolor-assisted technicolor (TC2) models. We find that the branching ratios $B_{r}(τ\longrightarrow l_{j}ν_τ\barν_τ)$ are larger than the branching ratios $B_{r}(τ\longrightarrow l_{j}ν_{l}\barν_{l})$ in all of the parameter space. Over a w

Alex Krasnitz, Yasushi Nara, Raju Venugopalan

We comment on the relation of our previous work on the classical gluodynamics of high energy nuclear collisions to recent work by Lappi (hep-ph/0303076). While our results for the non-perturbative number liberation coefficient agree, those for the energy disagree by a factor of 2. This discrepancy can be traced to an overall normalization error in our non-pe

D. V. Bandurin, N. B. Skachkov

A possibility of jet energy scale setting by help of ``p p -> Z0+jet+X&#39;&#39; process at LHC is studied. The effect of new set of cuts, proposed in our previous works, on the improvement of the Pt balance between Z0 boson and jet is demonstrated. The distributions of the selected events over Z0 transverse momentum and jet pseudorapidity are presented. A p

Bahram Mashhoon

The conceptual basis for the nonlocality of accelerated systems is presented. The nonlocal theory of accelerated observers and its consequences are briefly described. Nonlocal field equations are developed for the case of the electrodynamics of linearly accelerated systems.