February 2003 arXiv papers — page 13

J. Talbot, G. Tarjus, P. Viot

We obtain exact results for the acceptance ratio and mean squared displacement in Monte Carlo simulations of the simple harmonic oscillator in $D$ dimensions. When the trial displacement is made uniformly in the radius, we demonstrate that the results are independent of the dimensionality of the space. We also study the dynamics of the process via a spectral

Y. Zhao, X. F. Rui, C. H. Cheng, H. Zhang

MgB2-diamond nanocomposite superconductors have been synthesized by addition of nano-diamond powder. Microstructural analysis shows that the nanocomposite superconductor consists of tightly-packed MgB2 nano-grains (~50-100 nm) with highly-dispersed and uniformly-distributed diamond nanoparticles (~10-20 nm) inside the grains. The Jc-H and Hiir-T characterist

E. P. Yukalova, V. I. Yukalov

The peculiarities of electric current in semiconductors with nonuniform distribution of charge carriers are studied. The semiclassical drift-diffusion equations consisting of the continuity equations and the Poisson equation are solved numerically using Rusanov finite-difference scheme of third order. The different types of boundary conditions are numericall

Balázs Dóra, Attila Virosztek, Kazumi Maki

We investigate the effect of strong, nonmagnetic impurities on quasi-one-dimensional conventional and unconventional density waves (DW and UDW). The conventional case remains unaffected similarly to s-wave superconductors in the presence of weak, nonmagnetic impurities. The thermodynamic properties of UDW were found to be identical to those of a d-wave super

N. Gurappa, Prasanta K. Panigrahi

The present article is an extended version of the paper {\it Phys. Rev.} {\bf B 59}, R2490 (1999), where, we have established the equivalence of the Calogero-Sutherland model to decoupled oscillators. Here, we first employ the same approach for finding the eigenstates of a large class of Hamiltonians, dealing with correlated systems. A number of few and many

Z. Szotek, W. M. Temmerman, A. Svane, L. Petit

We present the self-interaction corrected local spin density (SIC-LSD) electronic structure and total energy calculations, leading also to valencies of the ground state configurations, for the half-metallic double perovskites such as Sr$_{2}$FeMoO$_{6}$, Ba$_{2}$FeMoO$_{6}$, Ca$_{2}$FeMoO$_{6}$, and Ca$_{2}$FeReO$_{6}$. We conclude that the Fe and Mo (or Re)

Silvia Kleff, Stefan Kehrein, Jan von Delft

We discuss the dynamics of a spin coupled to a damped harmonic oscillator. This system can be mapped to a spin-boson model with a structured bath, i.e. the spectral function of the bath has a resonance peak. We diagonalize the model by means of infinitesimal unitary transformations (flow equations), thereby decoupling the small quantum system from its enviro

A. Sherman, M. Schreiber

Using the method which retains the rotation symmetry of spin components in the paramagnetic state and has no preset magnetic ordering, spectral and magnetic properties of the two-dimensional t-J model in the normal state are investigated for the ranges of hole concentrations 0 <= x <= 0.16 and temperatures 0.01t <= T <= 0.2t. The used hopping t and exchange

Jacek Dziarmaga, Krzysztof Sacha

Atomic Bose-Einstein condensate is heated by atomic losses. Predicted depletion ranges from 1% for a uniform 3D condensate to around 10% for a quasi-1D condensate in a harmonic trap.

A. frydman, R. C. Dynes

We present transport and magnetoresistance (MR) measurements performed on quench condensed ultrathin films of Gd evaporated on an amorphous Ge or Sb layer. These films show a large negative MR accompanied by a hysteretic superimposed structure. When the film is coated by an overlayer of Ge or Sb the magnitude of the MR increases and the hysteretic structure

V. V. Khovailo, K. Oikawa, T. Abe, T. Takagi

The entropy change $ΔS$ between the high-temperature cubic phase and the low-temperature tetragonally-based martensitic phase of Ni$_{2+x}$Mn$_{1-x}$Ga ($x = 0 - 0.20$) alloys was studied. The experimental results obtained indicate that $ΔS$ in the Ni$_{2+x}$Mn$_{1-x}$Ga alloys increases with the Ni excess $x$. The increase of $ΔS$ is presumably accounted fo

Jian Qi Shen

The connections between the anti-shielding effect, negative absolute temperature and superluminal light propagation in both the instantaneously reversed electric field and the left-handed media are considered in the present paper. The instantaneous inversion of the exterior electric field may cause the electric dipoles into the state of negative absolute tem

Pablo I. Hurtado

In this thesis I study the dynamics of some nonequilibrium systems, using both computer simulations and theoretical tools. In particular, the following topics are studied: (i) metastability in a nonequilibrium ferromagnetic system, (ii) the onset of scale-free avalanches during metastable state decay, (iii) phase segregation under anisotropic nonequilibrium

D. H. E. Gross

Equilibrium statistics of Hamiltonian systems is correctly described by the microcanonical ensemble. Classically this is the manifold of all points in the $N-$body phase space with the given total energy. Due to Boltzmann&#39;s principle, $e^S=tr(δ(E-H))$, its geometrical size is related to the entropy $S(E,N,...)$. This definition does not invoke any inform

J. Lages, P. D. Sacramento, Z. Tesanovic

We calculate the density of states of a disordered inhomogeneous d-wave superconductor in a magnetic field. The field-induced vortices are assumed to be pinned at random positions and the effects of the scattering of the quasi-particles off the vortices are taken into account using the singular gauge transformation of Franz and Tesanovic. We find two regimes

Joseph Wakeling

We examine a simple biologically-motivated neural network, the three-layer version of the Chialvo-Bak `minibrain&#39; [Neurosci. 90 (1999) 1137], and present numerical results which indicate that a non-equilibrium phase transition between ordered and disordered phases occurs subject to the tuning of a control parameter. Scale-free behaviour is observed at th

Anca Constantin, Joseph C. Shields

Narrow Line Seyfert 1 (NLS1) galaxies are remarkable for their extreme continuum and emission line properties which are not well understood. New results bearing on the spectroscopic characteristics of these objects are presented here, with the aim of establishing their typical ultraviolet and optical spectral behavior. We employ HST observations of 22 NLS1s,

Steve B. Howell

We review the recent knowledge base pertaining to causes for mass accretion variations (high/low states) in highly magnetic cataclysmic variables (i.e. polars). We then examine what theory has to say about the properties of the secondary stars (the mass donors) with respect to those CVs with very short orbital periods. Finally, we use recent observations of

R. T. Zavala, G. B. Taylor

Rotation measure observations of 9 quasars, 4 BL Lacertae objects, and 3 radio galaxies are presented. The rest frame rotation measures in the cores of the quasars and the jets of the radio galaxy M87 are several thousand radians per meter squared. The BL Lacertae objects and the jets of the quasars have rest frame rotation measures of a few hundred radians

Charles R. Keeton, Joshua N. Winn

The strange morphology of the six-component gravitational lens PMN J0134-0931 has resisted explanation. We present the first successful quantitative models for the system, based on the idea that there are two lens galaxies and two components of the background source. One source is quintuply imaged and corresponds to the five brightest observed radio componen

Joshua N. Winn, Christopher S. Kochanek, Charles R. Keeton, James E. J. Lovell

We present results from high-resolution radio and optical observations of PMN J0134-0931, a gravitational lens with a unique radio morphology and an extremely red optical counterpart. Our data support the theory of Keeton & Winn (2003): five of the six observed radio components are multiple images of a single quasar, produced by a pair of lens galaxies. Mult

K. Wu, A. F. Tennant, D. A. Swartz, K. K. Ghosh

The X-ray sources observed in nearby galaxies show brightness distributions (log(N(>S))--log(S) curves) which can be described as single or broken power laws. Single power-law distributions are often found for sources in galaxies with vigorous ongoing star-formation activity, while broken power laws are found in elliptical galaxies and in bulges of spiral ga

Philip D. Mannheim

We show that detailed exploration of the $1<z<2$ redshift region can provide for definitive testing not only of the standard inflationary cosmological paradigm with its fine-tuned cosmological constant and its mysteriously late ($z<1$) onset of cosmic acceleration, but also for the non fine-tuned, alternate conformal cosmological model, a cosmology which acc

Alessandro Melchiorri, Carolina Odman

We compare the latest observations of Cosmic Microwave Background (CMB) Anisotropies with the theoretical predictions of the standard scenario of structure formation. Assuming a primordial power spectrum of adiabatic perturbations we found that the total energy density is constrained to be $Ω_{tot}=1.03\pm0.06$ while the energy density in baryon and Cold Dar

R. L. C. Starling, E. M. Puchnarewicz, E. Romero-Colmenero, K. O. Mason

We present a series of monitoring observations of the ultrasoft broad-line AGN RE J2248-511 with XMM-Newton. Previous X-ray observations showed a transition from a very soft state to a harder state five years later. We find that the ultrasoft X-ray excess has re-emerged, yet there is no change in the hard power-law. Reflection models with a reflection fracti

R. C. Bolton, G. Cotter, T. J. Pearson, G. G. Pooley

We present initial results from a follow-up of the 9C survey, complete to 25 mJy at 15 GHz, designed to assemble and investigate a sample of young radiosources. We have made radio continuum maps of 111 sources at frequencies spanning 1.4-43 GHz, and classified them according to their radio size and spectral index between 1.4 and 4.8 GHz. We find that selecti

G. Matt, S. Bianchi, M. Guainazzi, W. N. Brandt

We present and discuss Chandra and XMM-Newton observations of the Seyfert 2 galaxy and Compton-thick absorbed source, Tololo~0109-383. The hard X-ray emission (i.e. above $\sim$2 keV), is dominated by a spatially unresolved reflection component, as already discovered by previous ASCA and BeppoSAX observ ations. The soft X-ray emission is partly ($\sim$15%) e

G. K. Skinner

The concept of coded mask imaging in theory and in practice is reviewed, with particular emphasis on image reconstruction techniques. The techniques are simple in principle but become more complicated when one takes into account real, `as-built&#39;, instruments, as opposed to idealised imaginary ones. Procedures are discussed with particular reference to th

H. Schlattl, M. Salaris

We review the state of the art regarding the computation of the resistance coefficients in conditions typical of the stellar plasma, and compare the various results studying their effect on the solar model. We introduce and discuss for the first time in an astrophysical context the effect of quantum corrections to the evaluation of the resistance coefficient

Willy Kley

We study the evolution of a system consisting of two protoplanets still embedded in a protoplanetary disk. Results of two different numerical approaches are presented. In the first kind of model the motion of the disk material is followed by fully viscous hydrodynamical simulations, and the planetary motion is determined by N-body calculations including exac

S. Bianchi, I. Balestra, G. Matt, M. Guainazzi

We present a detailed discussion of the spectral and spatial components of NGC 5506, based on XMM-Newton, Chandra and BeppoSAX observations. The overall picture consists of a nucleus absorbed by cold gas with column density of $\approx10^{22}$ cm$^{-2}$ and surrounded by a Compton-thick torus, whose existence is inferred by a cold reflection component and an

W. Reich

32 GHz observations with the Effelsberg 100-m telescope revealed a highly polarized Galactic Centre filament: G0.087-0.087, running parallel to the well-known Arc structure. It has a similar flat spectrum, but it is an order of magnitude weaker. G0.087-0.087 is about 2.5&#39; or 6.2 pc long and located at the western boundary of the expanding molecular cloud

the HEGRA Collaboration, F. Aharonian

Using the HEGRA system of imaging atmospheric Cherenkov telescopes, the Andromeda galaxy (M31) was surveyed for TeV gamma ray emission. Given the large field of view of the HEGRA telescopes, three pointings were sufficient to cover all of M31, including also M32 and NGC205. No indications for point sources of TeV gamma rays were found. Upper limits are given

Werner Hofmann

A simple analysis technique is described which allows to intercalibrate the response of imaging atmospheric Cherenkov telescopes in stereoscopic telescope arrays at a level of 1-2%.

K. Omukai, F. Palla

The process of star formation from metal-free gas is investigated by following the evolution of accreting protostars with emphasis on the properties of massive objects. The main aim is to establish the physical processes that determine the upper mass limit of the first stars. Although the consensus is that massive stars were commonly formed in the first cosm

Alessandro B. Romeo, Cathy Horellou, Joeran Bergh

Noise is a problem of major concern for N-body simulations of structure formation in the early Universe, of galaxies and plasmas. Here for the first time we use wavelets to remove noise from N-body simulations of disc galaxies, and show that they become equivalent to simulations with two orders of magnitude more particles. We expect a comparable improvement

Paul R. Shapiro, Ilian T. Iliev, Alejandro C. Raga, Hugo Martel

We present the first gas dynamical simulations of the photoevaporation of cosmological minihalos overtaken by the ionization fronts which swept through the IGM during reionization in a LCDM universe, including the effects of radiative transfer. We demonstrate the phenomenon of I-front trapping inside minihalos, in which the weak, R-type fronts which traveled

Shakir M. Nagiyev, Elchin I. Jafarov, Rizvan M. Imanov

Exactly-solvable model of the linear singular oscillator in the relativistic configurational space is considered. We have found wavefunctions and energy spectrum for the model under study. It is shown that they have correct non-relativistic limits.

Sebastian de Haro, Annamaria Sinkovics, Kostas Skenderis

We discuss the computation of the leading corrections to D-brane solutions due to higher derivative terms in the corresponding low energy effective action. We develop several alternative methods for analyzing the problem. In particular, we derive an effective one-dimensional action from which the field equations for spherically symmetric two-block brane solu

Alejandro Ayala, Javier Magnin

We study the propagation properties of the rho vector in a dense and hot pion medium. We introduce a finite value of the chemical potential associated to a conserved pion number and argue that such description is valid during the hadronic phase of a relativistic heavy-ion collision, between chemical and thermal freeze-out, where the strong interaction drives

Kayll Lake

The information contained in galactic rotation curves is examined under a minimal set of assumptions. If emission occurs from stable circular geodesic orbits of a static spherically symmetric field, with information propagated to us along null geodesics, observed rotation curves determine galactic potentials without specific reference to any metric theory of

Simonetta Frittelli, Roberto Gomez

In the 3+1 framework of the Einstein equations for the case of vanishing shift vector and arbitrary lapse, we calculate explicitly the four boundary equations arising from the vanishing of the projection of the Einstein tensor along the normal to the boundary surface of the initial-boundary value problem. Such conditions take the form of evolution equations

Patrick Crotty, Julien Lesgourgues, Sergio Pastor

We show that the first year results of the Wilkinson Microwave Anisotropy Probe (WMAP) constrain very efficiently the energy density in relativistic particles in the universe. We derive new bounds on additional relativistic degrees of freedom expressed in terms of an excess in the effective number of light neutrinos Delta N_eff. Within the flat LambdaCDM sce

S. L. Bridle, A. M. Lewis, J. Weller, G. Efstathiou

We reconstruct the shape of the primordial power spectrum from the latest cosmic microwave background data, including the new results from the Wilkinson Microwave Anisotropy Probe (WMAP), and large scale structure data from the two degree field galaxy redshift survey (2dFGRS). We tested four parameterizations taking into account the uncertainties in four cos

Nima Arkani-Hamed, Matthew D. Schwartz

We study the physics of a single discrete gravitational extra dimension using the effective field theory for massive gravitons. We first consider a minimal discretization with 4D gravitons on the sites and nearest neighbor hopping terms. At the linear level, 5D continuum physics is recovered correctly, but at the non-linear level the theory becomes highly no

Chris Ford, Jan M. Pawlowski

Using the Nahm transform we investigate doubly periodic charge one SU(2) instantons with radial symmetry. Two special points where the Nahm zero modes have softer singularities are identified as the locations of instanton core constituents. For a square torus this constituent picture is closely reflected in the action density. In rectangular tori with large

Igor Shovkovy, Mei Huang

A new, gapless two-flavor color superconducting phase that appears under conditions of local charge neutrality and $β$-equilibrium is revealed. In this phase, the symmetry of the ground state is the same as in the conventional two-flavor color superconductor. In the low-energy spectrum of this phase, however, there are only two gapped fermionic quasiparticle

D. H. Coule

The recent paper of Lieu and Hillman [1] that a possible, (birefringence like) phase difference ambiguity coming from Planck effects would alter stellar images of distant sources is questioned. Instead for {\em division of wavefront} interference and diffraction phenomena, initial (lateral) coherence is developed simply by propagation of rays (cf. van Citter

Z. Li, S. Zhang

We propose a generalized stochastic Landau-Lifshitz equation and its corresponding Fokker-Planck equation for the magnetization dynamics in the presence of spin transfer torques. Since the spin transfer torque can pump a magnetic energy into the magnetic system, the equilibrium temperature of the magnetic system is ill-defined. We introduce an effective temp

I. P. Zois

We discuss the use of the language of operads to try to understand holography and through that quantum gravity. As we find out, the Deligne Conjecture and the action of the Grothendieck-Teichmuller group play an important role.

Armen Sedrakian

We develop a model of off-mass-shell pairing correlations in nuclear systems, which is based on the meson-exchange picture of nuclear interactions. The temporal retardations in the model are generated by the Fock-exchange diagrams. The kernel of the complex gap equation for baryons is related to the in-medium spectral function of mesons, which is evaluated n

G. E. Volovik

In contrast to the phenomenon of nullification of the cosmological constant in the equilibrium vacuum, which is the general property of any quantum vacuum, there are many options in modifying the Einstein equation to allow the cosmological constant to evolve in a non-equilibrium vacuum. An attempt is made to extend the Einstein equation in the direction sugg

S. Peysson

The Haldane-Shastry spin chain can be mapped to the infinite coupling limit of the SU(2) spin Calogero-Sutherland model. We use the $\mathfrak{gl}_2$ Jack polynomials&#39; technology to compute the form factors of the spin operator on the multi-spinon spectrum. The spin structure factor is obtained through a form factor expansion. The expansion is proven to

B. B. Deo, L. Maharana

A superstring action is quantised with Neveu Schwarz(NS) and Ramond(R) boundary conditions. The zero mass states of the NS sector are classified as the vector gluons, W-mesons, $B_μ$-mesons and scalars containing Higgs. The fifteen zero mass fermions are obtained from the Ramond sector. A space time supersymmetric Hamiltonian of the Standard Model is present

I. V. Mykytyuk

Let $G/K$ be an irreducible Hermitian symmetric spaces of compact type with the standard homogeneous complex structure. Then the real symplectic manifold $(T^*(G/K),Ω)$ has the natural complex structure $J^-$. We construct all $G$-invariant Kähler structures $(J,Ω)$ on homogeneous domains in $T^*(G/K)$ anticommuting with $J^-$. Each such a hypercomplex struc

Yong-Liang Ma, Qing Wang

Anomalous sector of chiral Lagrangian is calculated in a gauge invariant, nonlocal, dynamical quark model. The Wess-Zumino term is proved coming from two kinds of sources, one is independent on and another dependent on dynamical quark self energy $Σ(k^2)$. $p^6$ and more higher order anomalous sectors come only from $Σ(k^2)$ dependent source. After some canc

Debajyoti Choudhury, Anindya Datta, Katri Huitu

We argue that the $ZZH$ coupling constitutes a simple probe of the nature of the scalar sector responsible for electroweak symmetry breaking. We demonstrate the efficacy of this measure through an analysis of four-dimensional models containing scalars in arbitrary representation of $SU(2) \times U(1)$, as well as extra-dimensional models with a non-factoriza

Ishwaree P. Neupane

We study the properties of anti--de Sitter black holes with a Gauss-Bonnet term for various horizon topologies (k=0, \pm 1) and for various dimensions, with emphasis on the less well understood k=-1 solution. We find that the zero temperature (and zero energy density) extremal states are the local minima of the energy for AdS black holes with hyperbolic even

L. A. Klinkova, M. Uchida, Y. Matsui, V. I. Nikolaichik

Bismuthate superconductor Ba(1-x)K(x)BiO3 (x=0.27-0.49, Tc=25-32K) grown by an electrolysis technique was studied by electron diffraction and high-resolution electron microscopy. The crystalline structure thereof has been found to be non-cubic, of the layered nature, and non-centrosymmetric, with the lattice parameters a ~ ap, c ~ 2ap (ap is a simple cubic p

Camille Plenat

This paper has been withdrawn. The result anyway is still true for rational double points Dn. (the cases of E6,E7,E8 are not solved yet).

N. E. J. Bjerrum-Bohr

The relationship between on-shell tree level scattering amplitudes of open and closed strings, discovered some time ago by Kawai, Lewellen and Tye, is used at field theory level (at $O(α&#39;^3)$) to establish a link between the general relativity and the non-abelian Yang-Mills effective actions. Insisting at the effective Lagrangian level that any tree $N$

A. D. Martin, M. G. Ryskin, A. M. Stasto

We improve the accuracy of the extrapolation of the gluon distribution of the proton to very small x, and show that the charm production cross section, needed to calculate the cosmic ray-induced `atmospheric&#39; flux of ultrahigh energy prompt muon and tau neutrinos, may be predicted within perturbative QCD to within about a factor of three. We follow the s

Nicolas Borghini

Using a generating-function formalism, we compute the contribution of momentum conservation to multiparticle correlations between the emitted particles in high-energy collisions. In particular, we derive a compact expression of the genuine M-particle correlation, for arbitrary M.

E. Orignac, R. Citro

We investigate the phase diagram of a quarter filled Hubbard ladder with nearest-neighbor Coulomb repulsion using bosonization and renormalization group approach. Focusing on the strong-repulsion regime, we discuss the effect of an interchain exchange interaction J and interchain repulsion V on the possible ground states of the system and charge order config

Georges Audi

The ensemble of experimental data on the 2830 nuclides which have been observed since the beginning of Nuclear Physics are being evaluated, according to their nature, by different methods and by different groups. The two &#34;horizontal&#34; evaluations in which I am involved: the Atomic Mass Evaluation AME and the NUBASE evaluation belong to the class of &#

B. Hamprecht, H. Kleinert

We present a method for extracting tunnelling amplitudes from perturbation expansions which are always divergent and not Borel-summable. We show that they can be evaluated by an analytic continuation of variational perturbation theory. The power of the method is illustrated by calculating the imaginary parts of the partition function of the anharmonic oscill

Tomy Scaria

We examine the gauge generating nature of the translational subgroup of Wigner&#39;s little group for the case of massless tensor gauge theories and show that the gauge transformations generated by the translational group is only a subset of the complete set of gauge transformations. We also show that, just like the case of topologically massive gauge theori

Marc Hindry, Amílcar Pacheco

On the rank of Jacobians over function fields.} Let $f:\mathcal{X}\to C$ be a projective surface fibered over a curve and defined over a number field $k$. We give an interpretation of the rank of the Mordell-Weil group over $k(C)$ of the jacobian of the generic fibre (modulo the constant part) in terms of average of the traces of Frobenius on the fibers of $

R. Lednicky, V. L. Lyuboshitz, V. V. Lyuboshitz

The effect of the relativistic spin rotation on two--particle spin states, conditioned by the setting of the spins of the particles in their rest frames and by the noncommutativity of the Lorentz transformations along noncolinear directions, is discussed. Particularly, the transition from the c.m.s. of two spin-1/2 particles to the laboratory is considered.

V. Ravindran, J. Smith, W. L. van Neerven

We present the next-to-next-to-leading order (NNLO) corrections to the total cross section for (pseudo-) scalar Higgs boson production using an alternative method than those used in previous calculations. All QCD partonic subprocesses have been included and the computation is carried out in the effective Lagrangian approach which emerges from the standard mo

D. Dudal, H. Verschelde, R. E. Browne, J. A. Gracey

We discuss the 2-point-particle-irreducible (2PPI) expansion, which sums bubble graphs to all orders, in the context of SU(N) Yang-Mills theory in the Landau gauge. Using the method we investigate the possible existence of a gluon condensate of mass dimension two, <A^2>, and the corresponding non-zero vacuum energy. This condensate gives rise to a dynamicall

Katsushi Ito, Yasuhiro Sekino

We study superstring theories on the Penrose limit of the enhancon geometry realized by the D(p+4)-branes wrapped on a K3 surface. We first examine the null geodesics with fixed radius in general brane backgrounds, which give solvable superstring theories with constant masses. In most cases, the superstring theories contain negative mass-squared. We clarify

Stuart Wyithe, Abraham Loeb

The WMAP satellite has measured a large optical depth to electron scattering after cosmological recombination of 0.17+-0.04, implying significant reionization of the primordial gas only ~200 million years after the big bang. However, the most recent overlap of intergalactic HII regions must have occured at z<9 based on the Lyman-alpha forest constraint on th

Jen-Chi Lee

We give a simplified method to generate two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. Zero-norm states up to the fourth massive level and general formulas of some zero-norm tensor states at an arbitrary mass level are calculated. On-shell Ward identities generated by zero-norm states and the factor

Amir H. Fariborz

A collective treatment of the I=0 scalar mesons below 2 GeV [sigma (550), f0(980), f0(1370), f0(1500) and f0(1710)] in a non-linear chiral Lagrangian framework that is constrained by the mass and the partial decay widths of the I=1/2,1 scalars [kappa(900), K0*(1430), a0(980) and a0(1450)] is presented. The sub-structure of these states in terms of two and fo

Andrei I. Onishchenko, Oleg L. Veretin

We present results for two-loop QCD corrections to the short distance coefficient that governs leptonic decay of Bc-meson. After brief discussion of the technics of asymptotic threshold expansion used to perform this calculation, we give comments on the numerical value of two-loop corrections and its impact on NRQCD description of Bc-meson bound state dynami

Aaron Pierce, Hitoshi Murayama

Recent data from from the Wilkinson Microwave Anisotropy Probe (WMAP) place important bounds on the neutrino sector. The precise determination of the baryon number in the universe puts a strong constraint on the number of relativistic species during Big-Bang Nucleosynthesis. WMAP data, when combined with the 2dF Galaxy Redshift Survey (2dFGRS), also directly

L. L. Salcedo

In this Comment I point out some limitations of the proposal of Prezhdo and Brooksby for coupling quantum and classical degrees of freedom (Phys.Rev.Lett.86(2001)3215) if it is pushed too far.

Eran Mukamel, Konrad Banaszek, Ian A. Walmsley, Christophe Dorrer

We demonstrate experimentally a novel technique for characterizing transverse spatial coherence using the Wigner distribution function. The presented method is based on measuring interference between a pair of rotated and displaced replicas of the input beam with an area-integrating detector, and it can be superior in regimes when array detectors are not ava

Z. Ficek, R. Tanas

We investigate the role of the collective antisymmetric state in entanglement creation by spontaneous emission in a system of two non-overlapping two-level atoms. We calculate and illustrate graphically populations of the collective atomic states and the Wootters entanglement measure (concurrence) for two sets of initial atomic conditions. Our calculations i

C. King

This paper derives an inequality relating the p-norm of a positive 2 x 2 block matrix to the p-norm of the 2 x 2 matrix obtained by replacing each block by its p-norm. The inequality had been known for integer values of p, so the main contribution here is the extension to all values p >= 1. In a special case the result reproduces Hanner&#39;s inequality. As

Gary C. Hill

The incorporation of systematic uncertainties into confidence interval calculations has been addressed recently in a paper by Conrad et al. (Physical Review D 67 (2003) 012002). In their work, systematic uncertainities in detector efficiencies and background flux predictions were incorporated following the hybrid frequentist-Bayesian prescription of Cousins

C. Conti

Plane waves in Kerr media spontaneously generate paraxial X-waves (i.e. non-dispersive and non-diffractive pulsed beams) that get amplified along propagation. This effect can be considered a form of conical emission (i.e. spatio-temporal modulational instability), and can be used as a key for the interpretation of the out of axis energy emission in the split

Nina Byers

Enrico Fermi lived from 1901 to 1954, a period of great progress in physics and a period in which opportunities for women to study and work in institutions of higher learning increased significantly in Europe and North America. Though there are a few examples of women who made important contributions to physics in the 18th century such as Emilie du Chatelet

R. J. Lombard, C. Volpe

Very weakly bound systems may manifest intriguing &#34;universal&#34; properties, independent of the specific interaction which keeps the system bound. An interesting example is given by relations between the size of the system and the separation energy, or scaling laws. So far, scaling laws have been investigated for short-range and long-range (repulsive) p

A. Yu. Korchin, D. Van Neck, M. Waroquier

The chiral invariant QHD-III model of Serot and Walecka is applied in the calculation of some meson properties. The electromagnetic interaction is included by extending the symmetry of the model to the local U(1) \times SU(2)_{R} \times SU(2)_{L} group. The minimal and nonminimal contributions to the electromagnetic Lagrangian are obtained in a new represent

J. Carlson, J. Morales, V. R. Pandharipande, D. G. Ravenhall

Uniform neutron matter is approximated by a cubic box containing a finite number of neutrons, with periodic boundary conditions. We report variational and Green&#39;s function Monte Carlo calculations of the ground state of fourteen neutrons in a periodic box using the Argonne $\vep $ two-nucleon interaction at densities up to one and half times the nuclear

Gunnar S. Bali

I review recent lattice results on the spectrum and structure of baryons. Limitations due to the quenched approximation and un-physically heavy up and down quarks are discussed, and interfaces between first principles studies of QCD (or approximations to it) and ``model building&#39;&#39; are highlighted.

Peter Kodys, Jan Broz, Zdenek Dolezal

A new data acquisition program for personal computers with Windows operating system has been built at Charles University van de Graaff laboratory. It allows fast data acquisition from CAMAC and other PC interface cards using interrupt or polling mode via several types of crate controllers, basic on-line analysis and visualization of acquired data in graphs a

John D. Carter, Harvey Segur

The two-dimensional cubic nonlinear Schrodinger equation (NLS) can be used as a model of phenomena in physical systems ranging from waves on deep water to pulses in optical fibers. In this paper, we establish that every one-dimensional traveling wave solution of NLS with trivial phase is unstable with respect to some infinitesimal perturbation with two-dimen

Emilio Hernandez-Garcia, Cristobal Lopez, Zoltan Neufeld

Recently, it has been shown that properties of excitable media stirred by two-dimensional chaotic flows can be properly studied in a one-dimensional framework \cite{excitablePRL,excitablePRE}, describing the transverse profile of the filament-like structures observed in the system. Here, we perform a bifurcation analysis of this one-dimensional approximation

S. G. Glebov, O. M. Kiselev, V. A. Lazarev

In this paper we show a mechanism of the soliton generation in nonlinear Schrodinger equation due to a small fast oscillating driving force.

G. Sartori, G. Valente

Functions which are covariant or invariant under the transformations of a compact linear group $G$ acting in a euclidean space $\real^n$, can be profitably studied as functions defined in the orbit space of the group. The orbit space is the union of a finite set of strata, which are semialgebraic manifolds formed by the $G$-orbits with the same symmetry. In

Yanguang Charles Li

Recently, the author and collaborators have developed a systematic program for proving the existence of homoclinic orbits in partial differential equations. Two typical forms of homoclinic orbits thus obtained are: (1). transversal homoclinic orbits, (2). Silnikov homoclinic orbits. Around the transversal homoclinic orbits in infinite dimensional autonomous

Yanguang Charles Li

The global regularity for the viscous Boussinesq equations is proved.

Yanguang Charles Li

For a general evolution equation with a Silnikov homoclinic orbit, Smale horseshoes are constructed.

Yanguang Charles Li

In this paper, we study the discrete cubic nonlinear Schroedinger lattice under Hamiltonian perturbations. First we develop a complete isospectral theory relevant to the hyperbolic structures of the lattice without perturbations. In particular, Backlund-Darboux transformations are utilized to generate heteroclinic orbits and Melnikov vectors. Then we give co

Eugene V. Korotkov, Maria A. Korotkova, Nikolai A. Kudryashov

We developed a non-parametric method of Information Decomposition (ID) of a content of any symbolical sequence. The method is based on the calculation of Shannon mutual information between analyzed and artificial symbolical sequences, and allows the revealing of latent periodicity in any symbolical sequence. We show the stability of the ID method in the case

Ronaldo Garcia, Jorge Sotomayor

Here are studied pairs of transversal foliations with singularities, defined on the Elliptic region (where the Gaussian curvature $\mathcal K$ is positive) of an oriented surface immersed in $\mathbb R^3$. The leaves of the foliations are the lines of geometric mean curvature, along which the normal curvature is given by $\sqrt {\mathcal K}$, which is the ge

Mihail N. Kolountzakis, Szilard Gy. Revesz

The following problem originated from a question due to Paul Turan. Suppose $Ω$ is a convex body in Euclidean space $\RR^d$ or in $\TT^d$, which is symmetric about the origin. Over all positive definite functions supported in $Ω$, and with normalized value 1 at the origin, what is the largest possible value of their integral? From this Arestov, Berdysheva an