September 2003 arXiv papers — page 8

I. K. Baldry, K. Glazebrook, J. Brinkmann, Z. Ivezic

We analyse the bivariate distribution, in color versus absolute magnitude (u-r vs. M_r), of a low redshift sample of galaxies from the Sloan Digital Sky Survey (SDSS; 2400 deg^2, 0.004<z<0.08, -23.5<M_r<-15.5). We trace the bimodality of the distribution from luminous to faint galaxies by fitting double-Gaussians to the color functions separated in absolute

Karl D. Gordon

Studies of dust scattering properties in astrophysical objects with Milky Way interstellar dust are reviewed. Such objects are reflection nebulae, dark clouds, and the Diffuse Galactic Light (DGL). To ensure their basic quality, studies had to satisfy four basic criteria to be included in this review. These four criteria significantly reduced the scatter in

M. Grott, W. Glatzel, S. Chernigovski

The evolution of strange mode instabilities into the non linear regime has been followed by numerical simulation for an envelope model of a massive star having solar chemical composition, M=50M_sun, T_eff=10^4K and L=1.17*10^6 L_sun. Contrary to previously studied models, for these parameters shocks are captured in the H-ionisation zone and perform rapid osc

Matthew W. Kunz, Steven A. Balbus

The effects of ambipolar diffusion on the linear stability of weakly ionised accretion discs are examined. Earlier work on this topic has focused on axial magnetic fields and perturbation wavenumbers. We consider here more general field and wavenumber geometries, and find that qualitatively new results are obtained. Provided a radial wavenumber and azimuthal

M. Grott, S. Chernigovski, W. Glatzel

Strange mode instabilities in the envelopes of massive stars lead to shock waves, which can oscillate on a much shorter timescale than that associated with the primary instability. The phenomenon is studied by direct numerical simulation using a, with respect to time, implicit Lagrangian scheme, which allows for the variation by several orders of magnitude o

J. X. Wang, S. Malhotra, J. E. Rhoads, M. J. I. Brown

We present an analysis of a deep, 172 ks Chandra observation of the Large Area Lyman Alpha Survey (LALA) Boötes field, obtained with the Advanced CCD Imaging Spectrometer (ACIS-I) on the Chandra X-ray Observatory. This is one of the deepest Chandra images of the extragalactic sky; only the 2 Ms CDF-N and 1 Ms CDF-S are substantially deeper. A total of 168 X-

Maxim Yu. Khlopov

Cosmoparticle physics is the natural result of development of mutual relationship between cosmology and particle physics. Its prospects offer the way to study the theory of everything and the true history of the Universe, based on it, in the proper combination of their indirect physical, astrophysical and cosmological signatures. We may be near the first pos

Maxim Yu. Khlopov

The physical basis of the modern cosmological inflationary models with baryosynthesis and nonbaryonic dark matter and energy implies such predictions of particle theory, that, in turn, apply to cosmology for their test. It makes physics of early Universe ambiguous and particle model dependent. The study of modern cosmology is inevitably linked with the probe

W. Bian, Y. Zhao

In a previous paper (Bian & Zhao 2002), it was suggested that contamination to the luminosity of galactic nucleus from the host galaxies play an important role in determining parameters of the standard $α$ disk for AGNs. Using the nuclear absolute B band magnitude instead of the total absolute B band magnitude, the central black hole masses, the accretion ra

W. Bian, Y. Zhao

We used the widths of H$β$ and [OIII] emission lines to investigate the black hole--bulge relation in radio-loud AGNs, radio-quiet AGNs and NLS1s. The central black hole mass, $M_{bh}$, is estimated from the H$β$ line width and the optical luminosity, and the bulge velocity dispersion, $σ$, is directly from the width of [OIII] line. We found that the radio-q

Donald M. Terndrup, Deokkeun An, Angela Hansen, Ruth C. Peterson

We present a progress report on an extensive survey to find and characterize all types of blue horizontal-branch stars in the nuclear bulge of the Galaxy. We have obtained wide, shallow imaging in UBV of ~12 square degrees in the bulge, with follow-up spectroscopy for radial velocities and metal abundance determinations. We have discovered a number of metal-

A. De Rosa, L. Piro, G. Matt, G. C. Perola

We present the broad band analysis of two BeppoSAX observations of the Sy 1 Mkn509. In 2000 the source was in a typical flux state, F{2-10keV}=2.7x10^{-11}erg cm^{-2} s^{-1}, while in 1998 it was found in a high flux state, F{2-10keV}=5.7x10^{-11} erg cm^{-2} s^{-1}. A comparison between the two states shows a energy-dependent flux variation. A soft excess,

G. Meeus, M. Sterzik, J. Bouwman, A. Natta

We present mid-IR spectroscopy of three T Tauri stars in the young Chamealeon I dark cloud obtained with TIMMI2 on the ESO 3.6m telescope. In these three stars, the silicate emission band at 9.7 micron is prominent. We model it with a mixture of amorphous olivine grains of different size, crystalline silicates and silica. The fractional mass of these various

Kazuhiro Yamamoto

A formula to investigate wave effect in multi-lens system is presented on the basis of path integral formalism by generalizing the work by Nakamura and Deguchi (1999). Wave effect of a system with two lenses is investigated in an analytic way as a simple application to demonstrate usefulness of the formula and variety of wave effect in multi-lens system.

Guenter Sigl, Francesco Miniati, Torsten Ensslin

We investigate the impact of a structured universe in the multi-pole moments, auto-correlation function, and cluster statistics of cosmic rays above 10^19 eV. We compare structured and uniform source distributions with and without magnetic fields obtained from a cosmological simulation. We find that current data marginally favor structured source distributio

Kazuhiro Yamamoto, Keiji Tsunoda

The wave effect in the gravitational lensing phenomenon by a straight cosmic string is investigated. The interference pattern is expressed in terms of a simple formula. We demonstrate that modulations of the interfered wave amplitude can be a unique signature of the wave effect. We briefly mention a possible chance of detecting the wave effect in future grav

Philipp Richter

Significant progress has been made over the last few years to explore the gaseous halo of the Milky Way by way of absorption spectroscopy. I review recent results on absorption line studies in the halo using various instruments, such as the Far Ultraviolet Spectroscopic Explorer, the Space Telescope Imaging Spectrograph, and others. The new studies imply tha

Yoshiaki Hagiwara, Philip J Diamond, Makoto Miyoshi, Emmanouel Rovilos

Water vapor maser emission in the 6_{16}-5_{23} transition towards the narrow-line Seyfert 1 (NLS1) galaxy NGC 4051 has been discovered during an ongoing single-dish extragalactic water maser survey. The Doppler-shifted maser components appear to bracket maser components lying near the systemic velocity of the galaxy symmetrically. The tentative result of a

A. Tej, A. Lancon, M. Scholz, P. R. Wood

Pulsation models are crucial for the interpretation of spectrophotometric and interferometric observations of Mira variables. Comparing predicted and observed spectra is one way of establishing the validity of such models. In this paper, we focus on the models published between 1996 and 1998 by Bessell, Hofmann, Scholz and Wood. A few new model spectra are a

L. Zampieri, P. Mucciarelli, R. Falomo, P. Kaaret

We present new optical and {\it Chandra} observations of the field containing the ultraluminous X-ray source NGC1313 X-2. On an ESO 3.6 m image, the {\it Chandra} error box embraces a $R=21.6$ mag stellar-like object and excludes a previously proposed optical counterpart. The resulting X-ray/optical flux ratio of NGC 1313 X-2 is $\sim 500$. The value of $f_X

C. Cacciari, A. Bragaglia, E. Rossetti, F. Fusi Pecci

We present the results of the first observations, taken with FLAMES during Science Verification, of red giant branch (RGB) stars in the globular cluster NGC 2808. A total of 137 stars was observed, of which 20 at high resolution (R=47,000) with UVES and the others at lower resolution (R=19,000-29,000) with GIRAFFE in MEDUSA mode, monitoring ~ 3 mag down from

Adam Burrows, Christian D. Ott, Casey Meakin

There are many interesting topics at the intersection of physics and astrophysics we call Supernova Theory. A small subset of them include the origin of pulsar kicks, gravitational radiation signatures of core bounce, and the possible roles of neutrinos and rotation in the mechanism of explosion. In this brief communication we summarize various recent ideas

V. I. Pariev, Ya. N. Istomin, A. R. Beresnyak

We consider the propagation and stability of the helical electromagnetic perturbations in a relativistic force-free Pointing flux dominated jet (magnetic helix). Perturbations are found to dissipate energy in the vicinity of the resonant surfaces inside the jet, where the resonance of the perturbation with the Alfven waves occurs. The energy of the perturbat

Hiroshi Imai, Philip J. Diamond

With the VLBA, we have observed water masers associated with the OH/IR star, W43A, which trace a birth and growth of a molecular jet. The water masers exhibit the collimated distribution (1700 AU: 20 AU) and fast motions (+/-150 km/s). The maser distribution was well fit by a precessing jet model. The jet length has extended by 800 AU within 8 years, indicat

B. P. Gong

PSR B1937+21 was the first millisecond pulsar ever measured. Which has been appeared as a singular pulsar. The high-precision observation of this pulsar shows systemic long-term variation in the residual of time of arrivals. This paper modelled the secular variation by the orbital precession induced time delay of a binary pulsar system. The fitting requires

T. Jacobson, S. Liberati, D. Mattingly, F. W. Stecker

Constraints on possible Lorentz symmetry violation (LV) of order E/M_Planck for electrons and photons in the framework of effective field theory (EFT) are discussed. Using (i) the report of polarized MeV emission from GRB021206 and (ii) the absence of vacuum \v{C}erenkov radiation from synchrotron electrons in the Crab nebula, we improve previous bounds by 1

Robert D. Klauber

In addition to the two standard solutions of the quantum field equations having the form e^{+/-(iwt-ikx)}, there exist two additional solutions of the form e^{+/-(iwt+ikx). By incorporating these latter solutions, deemed &#34;supplemental solutions&#34;, into the development of quantum field theory, one finds a simple and natural cancellation of terms that r

T. G. Rappoport, P. Redlinski, X. Liu, G. Zarand

We report ferromagnetic and spin wave resonance absorption measurements on high quality epitaxially grown Ga_{1-x}Mn_{x}As thin films. We find that these films exhibit robust ferromagnetic long-range order, based on the fact that up to seven resonances are detected at low temperatures, and the resonance structure survives to temperatures close to the ferroma

Allan Adams, Anirban Basu, Savdeep Sethi

We construct dual descriptions of (0,2) gauged linear sigma models. In some cases, the dual is a (0,2) Landau-Ginzburg theory, while in other cases, it is a non-linear sigma model. The duality map defines an analogue of mirror symmetry for (0,2) theories. Using the dual description, we determine the instanton corrected chiral ring for some illustrative examp

Debanand Sa, Manas Sardar, G. Baskaran

Superconductivity in Na$_x$CoO$_2$$\cdot$yH$_2$O is likely to be a p or d-wave; however, experiments are unable to pinpoint the symmetry. A simple estimate of pair breaking effects from an unavoidable `Na$^+$ vacancy disorder&#39; in an ordered Na$^+$ lattice, at an optimal $x_{\rm opt} \approx 0.30$ is shown to destroy a Fermi liquid based p or d-wave super

Vamsi K. Akkineni, Uwe C. Tauber

We investigate the critical dynamics of the $n$-component relaxational models C and D which incorporate the coupling of a nonconserved and conserved order parameter S, respectively, to the conserved energy density rho, under nonequilibrium conditions by means of the dynamical renormalization group. Detailed balance violations can be implemented isotropically

M. Ebrahim Fouladvand, Zeinab Sadjadi, M. Reza Shaebani

We construct a stochastic cellular automata model for the description of vehicular traffic at a roundabout designed at the intersection of two perpendicular streets. The vehicular traffic is controlled by a self-organized scheme in which traffic lights are absent. This controlling method incorporates a yield-at-entry strategy for the approaching vehicles to

Maria Chiara Brambilla

We prove that a generic Steiner bundle E is simple if and only if the Euler characteristic of the endomorphism bundle of E is less or equal to 1. In particular we show that either E is exceptional or it satisfies the following inequality t\leq(\frac{n+1+\sqrt((n+1)^2-4)}{2})s.

Gergely Palla, Imre Derenyi, Illes Farkas, Tamas Vicsek

We provide a phenomenological theory for topological transitions in restructuring networks. In this statistical mechanical approach energy is assigned to the different network topologies and temperature is used as a quantity referring to the level of noise during the rewiring of the edges. The associated microscopic dynamics satisfies the detailed balance co

Jiannis K. Pachos, Almut Beige

It is shown that entangling two-qubit phase gates for quantum computation with atoms inside a resonant optical cavity can be generated via common laser addressing, essentially, within one step. The obtained dynamical or geometrical phases are produced by an evolution that is robust against dissipation in form of spontaneous emission from the atoms and the ca

Celia Anteneodo

The statistical properties of finite-time Lyapunov exponents at the Ulam point of the logistic map are investigated. The exact analytical expression for the autocorrelation function of one-step Lyapunov exponents is obtained, allowing the calculation of the variance of exponents computed over time intervals of length $n$. The variance anomalously decays as $

Adan Cabello

Clauser-Horne-Shimony-Holt inequality can give values between the classical bound, 2, and Tsirelson&#39;s bound, 2 \sqrt 2. However, for a given set of local observables, there are values in this range which no quantum state can attain. We provide the analytical expression for the corresponding bound for a parametrization of the local observables introduced

Andrea V. Maccio&#39;, Claudia Quercellini, Roberto Mainini, Luca Amendola

We present the results of a series of N-body simulations in cosmologies where dark matter (DM) is coupled to dark energy (DE), so easing the cosmic coincidence problem. The dark-dark coupling introduces two novel effects in N-body dynamics: (i) DM particle masses vary with time; (ii) gravity between DM particles is ruled by a constant $G^{*}$, greater than N

Ilarion V. Melnikov, M. Ronen Plesser, Sven Rinke

We clarify the discussion of N=2 supersymmetric boundary conditions for the classical d=2, N=(2,2) Non-Linear Sigma Model on an infinite strip. Our conclusions about the supersymmetric cycles match the results found in the literature. However, we find a constraint on the boundary action that is not satisfied by many boundary actions used in the literature.

Inge S. Helland

The aim of the paper is to derive essential elements of quantum mechanics from a parametric structure extending that of traditional mathematical statistics. The main extensions, which also can be motivated from an applied statistics point of view, relate to symmetry, the choice between complementary experiments and hence complementary parametric models, and

P. Monthoux

We study a model of quasiparticles on a two-dimensional square lattice coupled to Gaussian distributed dynamical fields. The model describes quasiparticles coupled to spin or charge fluctuations and is solved by a Monte Carlo sampling of the molecular field distributions. The non-perturbative solution is compared to various approximations based on diagrammat

Ashley P. Willis, Anvar Shukurov, Andrew Soward, Dmitry Sokoloff

The thin-disc global asymptotics are discussed for axisymmetric mean-field dynamos with vacuum boundary conditions allowing for non-local terms arising from a finite radial component of the mean magnetic field at the disc surface. This leads to an integro-differential operator in the equation for the radial distribution of the mean magnetic field strength, $

S. Benetti, P. Meikle, M. Stehle, G. Altavilla

We present optical/near-infrared photometry and spectra of the type Ia SN 2002bo spanning epochs from -13 days before maximum B-band light to +102 days after. The pre-maximum optical coverage is particularly complete. In some respects, SN 2002bo behaves as a typical &#34;Branch normal&#34; type Ia supernova (SN Ia) at optical and IR wavelengths. We find a B-

I. Kuzmenko

Dielectric properties of semiconductor substrate with imposed two dimensional (2D) periodic grid of quantum wires or nanotubes (quantum crossbars, QCB) are studied. It is shown that a capacitive contact between QCB and semiconductor substrate does not destroy the Luttinger liquid character of the long wave QCB excitations. However, the dielectric losses of a

Jun Sugiyama, Takumi Doi, Makoto Oka

Exotic penta-quark baryon with strangeness +1, Θ^+, is studied in the QCD sum rule approach. We derive sum rules for the positive and negative parity baryon states with J=1/2 and I=0. It is found that the standard values of the QCD condensates predict a negative parity Θ^+ of mass \simeq 1.5 GeV, while no positive parity state is found. We stress the roles o

S. Kluth

Results from the study of jets in hadronic final states produced in e+e- annihilation at sqrt(s)=14 to 209 GeV are discussed. Precise measurements of the strong coupling alpha_S at many points of sqrt(s) provide convincing evidence for the running of alpha_S as expected by QCD. Several measurements of the running b-quark mass m_b(M_Z) are combined yielding m

Koichi Matsuda, Hiroyuki Nishiura

We reanalyze the mass matrices model of quarks and leptons which gives a unified description of quark and lepton mass matrices with the same texture form. By investigating possible types of the assignment for the texture&#39;s components of this mass matrix form, we find that a different assignment for up-quarks from one for down-quarks can lead to consisten

G. Bonelli

The covariant quantization of the tensionless free bosonic (open and closed) strings in AdS spaces is obtained. This is done by representing the AdS space as an hyperboloid in a flat auxiliary space and by studying the resulting string constrained hamiltonian system in the tensionless limit. It turns out that the constraint algebra simplifies in the tensionl

Noriyuki Kogo, Makoto Matsumiya, Misao Sasaki, Jun&#39;ichi Yokoyama

We reconstruct the primordial spectrum of the curvature perturbation, $P(k)$, from the observational data of the Wilkinson Microwave Anisotropy Probe (WMAP) by the cosmic inversion method developed recently. In contrast to conventional parameter-fitting methods, our method can potentially reproduce small features in $P(k)$ with good accuracy. As a result, we

Masahiro Imachi, Yasuhiko Shinno, Hiroshi Yoneyama

In Monte Carlo simulations of lattice field theory with a $θ$ term, one confronts the complex weight problem, or the sign problem. This is circumvented by performing the Fourier transform of the topological charge distribution $P(Q)$. This procedure, however, causes flattening phenomenon of the free energy $f(θ)$, which makes study of the phase structure unf

Guido Cognola, Sergio Zerbini

Motivated by the study of quantum fields in a Friedman-Robertson-Walker (FRW) spacetime, the one-loop effective action for a scalar field defined in the ultrastatic manifold $R\times H^3/Γ$, $H^3/Γ$ being the finite volume, non-compact, hyperbolic spatial section, is investigated by a generalisation of zeta-function regularisation. It is shown that additiona

Nikolai G. Lehtinen, Peter W. Gorham, Abram R. Jacobson, Robert A. Roussel-Dupre

The FORTE (Fast On-orbit Recording of Transient Events) satellite records bursts of electromagnetic waves arising from near the Earth&#39;s surface in the radio frequency (RF) range of 30 to 300 MHz with a dual polarization antenna. We investigate the possible RF signature of ultra-high energy cosmic-ray particles in the form of coherent Cherenkov radiation

M. Ouchi, K. Shimasaku, S. Okamura, H. Furusawa

We investigate the clustering properties of 2,600 Lyman Break Galaxies (LBGs) at z=3.5-5.2 in two large blank fields, the Subaru Deep Field and the Subaru/XMM Deep Field (600arcmin^2 each). The angular correlation functions of these LBGs show a clear clustering at both z~4 and 5. The correlation lengths are r_0= 4.1^{+0.2}_{-0.2} and 5.9^{+1.3}_{-1.7} h_{100

Sumio Ishihara

We present a theory of the collective orbital excitation termed orbital wave in perovskite titanates and vanadates with the triply degenerate $t_{2g}$ orbitals. The dispersion relations of the orbital waves for the orbital ordered LaVO$_3$, YVO$_3$ and YTiO$_3$ are examined in the effective spin-orbital coupled Hamiltonians associated with the Jahn-Teller ty

Wei Jiang, Chao Han, Peng Xue, L. -M. Duan

We report experimental generation of non-classically correlated photon pairs from collective emission in a room-temperature atomic vapor cell. The nonclassical feature of the emission is demonstrated by observing a violation of the Cauchy-Schwarz inequality. Each pair of correlated photons are separated by a controllable time delay up to 2 microseconds. This

M. -C. Chang

We report the results of a search for the decay B^0 -> e^+ e^-, mu^+ mu^- and e^{+-} mu^{-+} based on an analysis of 78 fb^{-1} of data collected by the Belle detector at KEKB. No candidate events have been found. Upper limits on the branching fractions are calculated at the 90% confidence level: B(B^0 -> e^+ e^-) < 1.9 x 10^{-7}, B(B^0 -> mu^+ mu^-) < 1.6 x

Holger Lyre

Carl Friedrich von Weizsaecker&#39;s thinking has always crossed the borders between physics and philosophy. Being a physicist by training he still feels at home in the physics community, as a philosopher by passion, however, his mind cannot stop thinking at the limits of physics. His physical ideas are based on the general conceptual and methodological prec

T. W. Chen, C. K. Law, P. T. Leung

An in-depth theoretical study is carried out to examine the quasi-deterministic entanglement of two atoms inside a leaky cavity. Two $Λ$-type three-level atoms, initially in their ground states, may become maximally entangled through the interaction with a single photon. By working out an exact analytic solution, we show that the probability of success depen

Fedor Herbut

The concept of physical twin observables (PTO) for bipartite quantum states,introduced and proved relevant for quantum information theory in recent work, is substantially simplified. The relation of observable and state is studied in detail from the point of view of coherence entropy. Properties of this quantity are further explored. It is shown that, beside

Christian Raabe, Ludwig Knöll, Dirk-Gunnar Welsch

An expression for the Casimir stress on arbitrary dispersive and lossy linear magnetodielectric matter at finite temperature, including left-handed material, is derived and applied to spherical systems. To cast the relevant part of the scattering Green tensor for a general magnetodielectric sphere in a convenient form, classical Mie scattering is reformulate

Graeme Mitchison, Richard Jozsa

Let S be the von Neumann entropy of a finite ensemble E of pure quantum states. We show that S may be naturally viewed as a function of a set of geometrical volumes in Hilbert space defined by the states and that S is monotonically increasing in each of these variables. Since S is the Schumacher compression limit of E, this monotonicity property suggests a g

Zafar Ahmed

We present the case of quantal transmission through a smooth, single-piece exponential potential, $V(x)=-V_0 e^{x/a}$, in contrast to the piece-wise continuous potentials, as a pedagogic model to demonstrate the analytic extraction of transmission (reflection) co-efficient.

Eugeniy E. Mikhailov, Yuri V. Rostovtsev, George R. Welch

We study the behavior of the group velocity of light under conditions of electromagnetically induced transparency (EIT) in a Doppler broadened medium. Specifically, we show how the group delay (or group velocity) of probe and generated Stokes fields depends on the one-photon detuning of drive and probe fields. We find that for atoms in a buffer gas the group

Jason E. Ollerenshaw, Daniel A. Lidar, Lewis E. Kay

We report the realization, using nuclear magnetic resonance techniques, of the first quantum computer that reliably executes an algorithm in the presence of strong decoherence. The computer is based on a quantum error avoidance code that protects against a class of multiple-qubit errors. The code stores two decoherence-free logical qubits in four noisy physi

A. L. Khomkin, I. A. Mulenko

A theoretical model of vapor-liquid phase transition in a system of charged hard cores of different diameters is suggested (with the parameters of the transition obtained in a number of studies using the Monte Carlo method). The model is based on the assumption that, in the neighborhood of the critical point, the system of charged cores is a mixture of multi

M. Zamboni Rached, Amr Shaarawi, Erasmo Recami

The space-time focusing of a (continuous) succession of localized X-shaped pulses is obtained by suitably integrating over their speed, i.e., over their axicon angle, thus generalizing a previous (discrete) approach. First, new Superluminal wave pulses are constructed, and then tailored in such a wave to get them temporally focused at a chosen spatial point,

A. K Ciftci, E. Recepoglu, O. Yavas, S. Sultansoy

Main parameters of the linac-ring type charm-tau factory are discussed. Different sets of parameters for an electron linac and a positron ring have been considered. It is shown that L=10^33 cm-2 s-1 and even more can be achieved. The physics goals of this machine in investigation for charmed particles and tau lepton properties are briefly discussed. Advantag

S. R. Souza, R. Donangelo, W. G. Lynch, W. P. Tan

We show that the qualitative behavior of the nuclear caloric curve can be inferred from the energy dependence of the isoscaling parameters. Since there are strong indications that the latter are not distorted by the secondary decay of primary hot fragments, in contrast to other observables, this suggests that valuable information on the nuclear caloric curve

Akinobu Dote, Hisashi Horiuchi, Yoshinori Akaishi, Toshimitsu Yamazaki

We have developed a new framework of Antisymmetrized Molecular Dynamics (AMD), to adequately treat the I=0 KN interaction, which is essential to study kaonic nuclei. The improved points are 1) pK$^-$/nK$^0$ mixing and 2) total spin and isospin projections. These improvements enable us to investigate various kaonic nuclei (ppnK$^-$, pppK$^-$, pppnK$^-$, $^6$B

A. Maj, M. Kmiecik, A. Bracco, F. Camera

The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows

Shaun N. Mosley

The Laplacian in spherical coordinates contains the squared radial momentum operator $ p_r^2 = - r^{-1} \partial_r^2 r $ which is Hermitian and positive. However as has been pointed out by various authors the ``radial momentum operator&#34; $ - i r^{-1} \partial_r r $ is not Hermitian. The positive square root operator of $ p_r^2 $ is found and also its inve

Miroslav Andrle, Cestmir Burdik, Jean-Pierre Gazeau

A spline wavelets construction of class C^n(R) supported by sequences of aperiodic discretizations of R is presented. The construction is based on multiresolution analysis recently elaborated by G. Bernuau. At a given scale, we consider discretizations that are sets of left-hand ends of tiles in a self-similar tiling of the real line with finite local comple

Claude Bardos, Francois Golse, Alex D. Gottlieb, Norbert J. Mauser

This article examines the time-dependent Hartree-Fock (TDHF) approximation of single-particle dynamics in systems of interacting fermions. We find the TDHF approximation to be accurate when there are sufficiently many particles and the initial many-particle state is a Slater determinant, or any Gibbs equilibrium state for noninteracting fermions. Assuming a

Martial Agueh

We obtain solutions of the nonlinear degenerate parabolic equation \[ \frac{\partial ρ}{\partial t} = {div} \Big\{ρ\nabla c^\star [ \nabla (F^\prime(ρ)+V) ] \Big\} \] as a steepest descent of an energy with respect to a convex cost functional. The method used here is variational. It requires less uniform convexity assumption than that imposed by Alt and Luck

Jeffrey R. Weeks

This chapter from the upcoming Handbook of Knot Theory (eds. Menasco and Thistlethwaite) shows how to construct hyperbolic structures on link complements and perform hyperbolic Dehn filling. Along with a new elementary exposition of the standard ideas from Thurston&#39;s work, the article includes never-before-published explanations of SnapPea&#39;s algorith

Edward Odell, Hans-Olav Tylli

The Banach space $E$ has the weakly compact approximation property (W.A.P. for short) if there is a constant $C < \infty$ so that for any weakly compact set $D \subset E$ and $ε> 0$ there is a weakly compact operator $V: E \to E$ satisfying $\sup_{x\in D} || x - Vx || < ε$ and $|| V|| \leq C$. We give several examples of Banach spaces both with and without t

D. Constantine, M. Darnall

We present a proof of an upper bound for the lengths of finite dimensional representations of algebras obeying a modified PBW property, including Lie algebras and quantum groups. The sharpness of the bound is proved and discussed.

Jean Dezert, Florentin Smarandache

In this paper, we examine several issues for ordering or partially ordering elements of hyper-powertsets involved in the recent theory of plausible, uncertain and paradoxical reasoning (DSmT or Dezert-Smarandache Theory) developed by the authors. We will show the benefit of some of these issues to obtain a nice and useful matrix representation of belief func

Simona Paoli

An algebraic category $\mathcal{C}$ is called balanced if the cotriple cohomology of any object of $\mathcal{C}$ vanishes in positive dimensions on injective coefficient modules. Important examples of balanced and of non-balanced categories occur in the literature. In this paper we prove that the category of crossed modules in groups is non-balanced.

M. V. Catalisano, A. V. Geramita, A. Gimigliano

We study the dimension of the higher secant varieties $X^s$ of ${\Bbb X} = {\Bbb P}^{n_1}\times ...\times {\Bbb P}^{n_t}$ embedded the morphism given by ${\cal O}_{\Bbb X}({a_1,...,a_t})$. We call it a {\it Segre-Veronese variety} and the embedding a {\it Segre-Veronese embedding}. In several cases (e.g. for 3 factors {\Bbb P}^{1}, or when $s$ is small) we s

Michael T. Jury, David W. Kribs

Given a row contraction of operators on Hilbert space and a family of projections on the space which stabilize the operators, we show there is a unique minimal joint dilation to a row contraction of partial isometries which satisfy natural relations. For a fixed row contraction the set of all dilations forms a partially ordered set with a largest and smalles

Michael T. Jury, David W. Kribs

A free semigroupoid algebra is the weak operator topology closed algebra generated by the left regular representation of a directed graph. We establish lattice isomorphisms between ideals and invariant subspaces, and this leads to a complete description of the weak operator topology closed ideal structure for these algebras. We prove a distance formula to id

Astrid an Huef, Iain Raeburn

Suppose that $G$ is a locally compact group and $π$ is a (not necessarily irreducible) unitary representation of a closed normal subgroup $N$ of $G$ on a Hilbert space $H$. We extend results of Clifford and Mackey to determine when $π$ extends to a unitary representation of $G$ on the same space $H$ in terms of a cohomological obstruction.

G. Benkart, A. Elduque, C. Martinez

We determine the Lie superalgebras over fields of characteristic zero that are graded by the root system A(n,n) of the special linear Lie superalgebra psl(n+1,n+1).

David W. Kribs, Stephen C. Power

We say that a nonselfadjoint operator algebra is partly free if it contains a free semigroup algebra. Motivation for such algebras occurs in the setting of what we call free semigroupoid algebras. These are the weak operator topology closed algebras generated by the left regular representations of semigroupoids associated with finite or countable directed gr

Gregory Lupton

We give an explicit formula for the rational category of an elliptic space whose minimal model has a homogeneous-length differential. We also show that for such a space, there are no gaps in the sequence of integers realized as the rational Toomer invariant of some cohomology class. With an additional hypothesis, we show a result from which we deduce the rel

Holger Rauhut, Margit Rösler

We present a construction of a wavelet-type orthonormal basis for the space of radial $L^2$-functions in $\R^3$ via the concept of a radial multiresolution analysis. The elements of the basis are obtained from a single radial wavelet by usual dilations and generalized translations. Hereby the generalized translation reveals the group convolution of radial fu

Philip Foth, Jiang-Hua Lu

We present some basic results on a natural Poisson structure on any compact symmetric space. The symplectic leaves of this structure are related to the orbits of the corresponding real semisimple group on the complex flag manifold.

Suphot Musiri, George Siopsis

We calculate analytically asymptotic values of quasi-normal frequencies of four-dimensional Kerr black holes by solving the Teukolsky wave equation. We obtain an expression for arbitrary spin of the wave in agreement with Hod&#39;s proposal which is based on Bohr&#39;s correspondence principle. However, the range of frequencies is bounded from above by $1/a$

John E. Wang

The time dependent formation of an electric flux tube (fundamental string) is reviewed. The main tool used for analysis is the Spacelike brane, which is a kink in time of the rolling tachyon. Both the S-brane and rolling tachyon are attempts to extend the D-brane concept to time dependent backgrounds. While S-branes are similar to Euclidean counterparts of t

Antonio Bassetto, Federica Vian

Planarity was introduced by &#39;t Hooft in his topological classification of diagrams in the large-N limit of U(N) gauge theories. Planarity also occurs in noncommutative field theories where amplitudes possess invariance only under cyclic permutations, a feature inherited from the parent string theory. In noncommutative gauge theories both kinds of planari

Harmen J. Warringa

The thermodynamics of the O(N) nonlinear sigma model in 1+1 dimensions is studied. We calculate the finite temperature effective potential in leading order in the 1/N expansion and show that at this order the effective potential can be made finite by temperature independent renormalization. We will show that this is not longer possible at next-to-leading ord

Edmond Iancu, A. H. Mueller

We argue that one cannot correctly calculate the elastic scattering S-matrix for high-energy dipole-dipole scattering, in the region where S is small, without taking fluctuations into account. The relevant fluctuations are rare and unimportant for general properties of inelastic collisions. We find that the Kovchegov equation, while giving the form of the S-

Paul H. Frampton

The use of the AdS/CFT correspondence to arrive at quiver gauge field theories is discussed, focussing on the orbifolded case without supersymmetry. An abelian orbifold with the finite group Z(12) can accommodate unification at about 4 TeV.

A. Denner, S. Dittmaier, M. Roth, M. M. Weber

We have calculated the complete O(alpha) and O(alpha_s) radiative corrections to the Higgs-production process e+ e- -> t anti-t H in the Standard Model. This process is particularly interesting for the measurement of the top-quark Yukawa coupling at a future e+ e- collider. The calculation of the O(alpha) corrections is described in some detail including, in

B. S. Zou, H. C. Chiang

For the Nbar N system, the one-pion-exchange (OPE) interaction gives the largest attractive force for Nbar N with isospin I=0 and spin S=0, while a near threshold enhancement was observed for pbar p with I=0 and S=0 in J/psi -> gamma pbar p decays. With a K-matrix approach, we find that the OPE final-state-interaction (FSI) makes an important contribution to

Hael Collins, Matthew R. Martin

While inflaton loops in the Euclidean vacuum generally have a negligible contribution to the power spectrum, loop effects can be substantially larger when the inflaton is in a non-thermal vacuum state. As an example, we show that in a truncated alpha-vacuum these loop effects are enhanced by the ratio of the Planck scale to the Hubble scale during inflation.

Bhaskar De, S. Bhattacharyya

The newly proposed combinational approach, called the grand combinational model (GCM), as would be described in detail in the text, is still under our careful scrutiny. By applying it, we have attempted to analyze here the characteristics of both the transverse momentum($p_{\rm{T}}$)-, and centrality-dependence of production of the main varieties of the seco

H. Arisue, T. Fujiwara, K. Tabata

The new algorithm of the finite lattice method is applied to generate the high-temperature expansion series of the simple cubic Ising model to $β^{50}$ for the free energy, to $β^{32}$ for the magnetic susceptibility and to $β^{29}$ for the second moment correlation length. The series are analyzed to give the precise value of the critical point and the criti

R. Frezzotti, G. C. Rossi

It is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with standard and twisted Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign. To avoid the problem of the spurious zero-modes of the Wilson--Dirac operator