September 2002 arXiv papers — page 21

Bernhard Krön

Combining the study of the simple random walk on graphs, generating functions (especially Green functions), complex dynamics and general complex analysis we introduce a new method of spectral analysis on self-similar graphs. We give an axiomatic definition of self-similar graphs which correspond to general nested but not necessarily finitely ramified fractal

Bernhard Krön

Locally finite self-similar graphs with bounded geometry and without bounded geometry as well as non-locally finite self-similar graphs are characterized by the structure of their cell graphs. Geometric properties concerning the volume growth and distances in cell graphs are discussed. The length scaling factor $ν$ and the volume scaling factor $μ$ can be de

Hitoshi Nishino, Subhash Rajpoot

We present a topologically non-trivial generalization of gauged N=16 supergravity on the coset E_8 / SO(16) in three-dimensions. This formulation is based on a combination of BF-term and a Chern-Simons term for an SO(16) gauge field A_\m{}^{I J}. The fact that an additional vector field B_\m{}^{I J} is physical and propagating with couplings to σ-model field

Joseph Polchinski

I review our current understanding of the Worldformula, M theory, focusing on themes from the work of Heisenberg.

Henriette Elvang, Joseph Polchinski

Zhang and Hu have formulated an SU(2) quantum Hall system on the four-sphere, with interesting three-dimensional boundary dynamics including gapless states of nonzero helicity. In order to understand the local physics of their model we study the U(1) and SU(2) quantum Hall systems on flat R^4, with flat boundary R^3. In the U(1) case the boundary dynamics is

Gleb Arutyunov, Emery Sokatchev

We discuss the perturbative behavior of the 1/2 BPS operators in N=2 SCFT on the example of two very similar quadrilinear composite operators made out of hypermultiplets. An explicit one-loop computation shows that one of them is protected while the other acquires an anomalous dimension. Although both operators are superconformal primaries in the free case,

Skuli Gudmundsson, Charles B. Thorn, Tuan A. Tran

We extend the Bardakci-Thorn (BT) worldsheet formalism to supersymmetric non-abelian gauge theory. Our method covers the cases of N =1,2,4 extended supersymmetry. This task requires the introduction of spinor valued Grassmann variables on the worldsheet analogous to those of the supersymmetric formulation of superstring theory. As in the pure Yang-Mills case

Nick Dorey, Timothy J. Hollowood, S. Prem Kumar, Annamaria Sinkovics

In this note we show how Dijkgraaf and Vafa's hypothesis relating the exact superpotential of an N=1 theory to a matrix model can be used to describe all the massive vacua of the N=1*, or mass deformed N=4, theory including the Higgs vacuum. The matrix model computation of the superpotential for each massive vacuum independently yields a modular function

N. A. Gromov, I. V. Kostyakov, V. V. Kuratov

We define a class of orthosymplectic $osp(m;j|2n;ω)$ and unitary $sl(m;j|n;ε)$ superalgebras which may be obtained from $osp(m|2n)$ and $sl(m|n)$ by contractions and analytic continuations in a similar way as the special linear, orthogonal and the symplectic Cayley-Klein algebras are obtained from the corresponding classical ones. Casimir operators of Cayley

Nahomi Kan, Kenji Sakamoto, Kiyoshi Shiraishi

We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the WLPNGB is calculated from the one-loop quantum effect of scalar fields at zero and finite temperature. We show that a series expansion by the modified Bessel functions is useful to calculate the one-loop effective potentials.

Dmitri V. Alekseevsky, Vicente Cortés, Chandrashekar Devchand

We describe two extensions of the notion of a self-dual connection in a vector bundle over a manifold M from dim M=4 to higher dimensions. The first extension, Omega-self-duality, is based on the existence of an appropriate 4-form Omega on the Riemannian manifold M and yields solutions of the Yang-Mills equations. The second is the notion of half-flatness, w

R. de Lima Rodrigues

Starting with the Lagrangian formalism with N=2 supersymmetry in terms of two Grassmann variables in Classical Mechanics, the Dirac canonical quantization method is implemented. The N=2 supersymmetry algebra is associated to one-component and two-component eigenfunctions considered in the Schrödinger picture of Nonrelativistic Quantum Mechanics. Applications

Carlos Contreras, Gorazd Cvetic, Kwang Sik Jeong, Taekoon Lee

We recapitulate the method which resums the truncated perturbation series of a physical observable in a way which takes into account the structure of the leading infrared renormalon. We apply the method to the Gross-Llewellyn Smith (GLS) sum rule. By confronting the obtained result with the experimentally extracted GLS value, we determine the value of the QC

A. P. Kostyuk

Production of open and hidden charm hadrons in heavy ion collisions is considered within the statistical coalescence model. The charmed quark-antiquark pairs are assumed to be created at the initial stage of the reaction in hard parton collisions. The number of these pairs is conserved during the evolution of the system. At the hadronization stage, the charm

Altug Arda, Muge Boz

Starting with the most general effective Hamiltonian comprising scalar and vector operators beyond the standard model, we discuss the impact of various operators on the zero of the forward--backward asymmetry in the dileptonic B decay B -> K^\ast μ^+ μ^-. We find that, zero of the asymmetry is highly sensitive to the sign and size of the vector--vector opera

Eduard Masso

I review the theoretical motivation for the axion and present an update of the experimental status of axion searches. I finally comment on some aspects of the physics of axion-like particles.

A. Yu. Smirnov

Recent SNO results give strong evidence that the solar neutrinos undergo the flavor conversion. Main issue now is the identification of the mechanism of conversion. The LMA MSW solution with $Δm^2 = (5 - 7) \cdot 10^{-5}$ eV$^2$, $\tan^2 θ= 0.35 - 0.45$ looks rather plausible: it fits well the experimental data and our new theoretical prejudices. In the LMA

H. Athar

High energy neutrinos with energy typically greater than tens of thousands of GeV may originate from several astrophysical sources. The sources may include, for instance, our galaxy, the active centers of nearby galaxies, as well as possibly the distant sites of gamma ray bursts. I briefly review some aspects of production and propagation as well as prospect

Ana M. Teixeira

We briefly comment on the question of spontaneous CP violation for several models of weak interactions. We focus on one of the minimal extensions of the Standard Model where spontaneous CP violation is viable,the next-to-minimal supersymmetric standard model (NMSSM), with two Higgs doublets and a gauge singlet. We analyse the most general Higgs potential wit

Antonio Pineda

We briefly summarize some results obtained by potential NRQCD in the non perturbative regime: 1) a systematic procedure to obtain the heavy quarkonium potential in the 1/m expansion (with explicit expressions up to O(1/m^2) in terms of Wilson loops), and 2) a description of the heavy quarkonium inclusive decays to light particles, and of the NRQCD matrix ele

Osamu Yasuda

I briefly review the recent status of research on physics potential of neutrino factories including the discussions on parameter degeneracy.

Xing-Gang Wu, Chao-Hsi Chang, Yu-Qi Chen, Zheng-Yun Fang

The annihilation of the $B_c$ meson to leptons and inclusive light hadrons is analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find that the decay mode, which escapes from the helicity suppression, contributes a sizable fraction width. According to the analysis, the branching ratio due to the contribution from the color-singlet comp

A. Abada, D. Becirevic, Ph. Boucaud, J. M. Flynn

New (preliminary) results for the form factors relevant for the semileptonic decays of heavy pseudoscalar to a light vector meson are presented. In particular, we discuss the form factors for D --> K* and B --> rho modes.

Z. Fodor, S. D. Katz, G. Papp

A PC-based parallel computer for medium/large scale lattice QCD simulations is suggested. The Eotvos Univ., Inst. Theor. Phys. cluster consists of 137 Intel P4-1.7GHz nodes. Gigabit Ethernet cards are used for nearest neighbor communication in a two-dimensional mesh. The sustained performance for dynamical staggered(wilson) quarks on large lattices is around

F. Csikor, G. I. Egri, Z. Fodor, S. D. Katz

We calculate the pressure (p), the energy density (ε) and the baryon density (n_B) of QCD at finite temperatures (T) and chemical potentials (μ). The recently proposed overlap improving multi-parameter reweighting technique is used to determine observables at nonvanishing chemical potentials. Our results are obtained by studying n_f=2+1 dynamical staggered q

M. Guagnelli, R. Petronzio, N. Tantalo

In this paper we extend the estimate of the value of the lattice spacing a in units of the r0 scale at values of the bare coupling larger than those available. By using results from the computation of the renormalised coupling in the Schroedinger functional formalism we find that from beta \simeq 7 onward the behaviour predicted by asymptotic freedom at tree

A. Ali Khan, T. Bakeyev, M. Göckeler, R. Horsley

For lattice calculations with light dynamical quarks, finite size effects have become an important aspect. We study finite size effects in nucleon masses on N_f=2 dynamical lattices of 1-2 fm. Predictions for the finite size effects are obtained in one-loop chiral perturbation theory.

G. Colangelo, S. Dürr, R. Sommer

We present a determination of the shift $M_π(L)-M_π$ due to the finite spatial box size $L$ by means of $N_f=2$ Chiral Perturbation Theory and Lüscher's formula. The range of applicability of the chiral prediction is discussed.

K. Jimmy Juge, Julius Kuti, Colin Morningstar

Results from a comprehensive new analysis on the excitation spectrum of the QCD string are presented. A rapid onset of string formation is observed in the spectrum on a length scale of 2 fm, with Dirichlet boundary conditions. The crossover from the short distance spectrum towards string excitations and an observed fine structure in the 1--3 fm range are rel

P. Mitra

It is pointed out that any CP violation which may be found in lattice QCD with a chiral phase in the fermion mass term cannot be relevant for the continuum theory. CP is classically conserved in the corresponding continuum theory and is non-anomalous.

Feng Liu

Based on 3.26 fb$^{-1}$ data sample collected at CLEO III, we study the decay $τ^-\to K^+K^-π^-ν_τ$, and improve the measurement of the branching ratio ${\cal B}(τ^-\to K^+K^-π^-ν_τ)= (1.59\pm0.06\pm0.13)\times10^{-3}$, the results are preliminary.

R. A. Briere

We measured two moments of the lepton momentum spectrum in B -> X l nu, where l= e or mu, for p_l > 1.5 GeV/c. From these we derive the Heavy Quark Expansion (HQE) parameters Lambda-bar(MS-bar) = 0.39 +- 0.03(stat) +- 0.06(sys) +- 0.12(th) GeV and lambda_1 = -0.25 +- 0.02(stat) +- 0.05(sys) +- 0.14(th) GeV^2, through order 1/M_B^3 in the non-perturbative exp

Giacomo Sguazzoni

The topologies arising from the production of supersymmetric particles at the LEP collider are briefly reviewed recalling detector requirements, simulation and other experimental issues.

S. Tomizawa, M. Siino

We propose a method to determine the topological structure of an event horizon far in the future of a spacetime from the geometrical information of its future null infinity. In the present article, we mainly consider spacetimes with two black holes. Although, in most of cases, the black holes coalesce and their event horizon is topologically a single sphere

Sanjay M Wagh, Keshlan S Govinder

It is well-known \cite{mtbh} that {\em all} black hole solutions of General Relativity are of Petrov-type D. It may thus be expected that the spacetime of {\em physically realizable} spherical gravitational collapse is also of Petrov-type D. We show that a radially homothetic spacetime, {\em ie}, a spherically symmetric spacetime with hyper-surface orthogona

Gerald Kaiser

Electromagnetic wavelets are a family of 3x3 matrix fields W_z(x') parameterized by complex spacetime points z=x+iy with y timelike. They are translates of a \sl basic \rm wavelet W(z) holomorphic in the future-oriented union T of the forward and backward tubes. Applied to a complex polarization vector p (representing electric and magnetic dipole moments

Benny Lehmann, Daniel Lehmann, Noam Nisan

In most of microeconomic theory, consumers are assumed to exhibit decreasing marginal utilities. This paper considers combinatorial auctions among such submodular buyers. The valuations of such buyers are placed within a hierarchy of valuations that exhibit no complementarities, a hierarchy that includes also OR and XOR combinations of singleton valuations,

T. Ebihara, A. L. Cornelius, J. M. Lawrence, S. Uji

We show for the intermediate valence compound YbAl$_{3}$ that the high field (40 $\lesssim B \lesssim$ 60T) effective masses measured by the de Haas-van Alphen experiment for field along the $<111>$ direction are smaller by approximately a factor of two than the low field masses. The field $B^{*} \sim$ 40T for this reduction is much smaller than the Kondo fi

M. A. Shahzamanian, R. Afzali

The scattering processes between the quasiparticles in spin- up superfluid with the quasiparticles in spin-down normal fluid are added to the other relevant scattering processes in the Boltzmann collision terms. The Boltzmann equation has been solved exactly for temperatures just below T_c_1. The shear viscosity component of the A_1- phase drops as C_1(1-T/T

G. Kontrym-Sznajd, M. Samsel-Czekala, A. Pietraszko, H. Sormann

A simultaneous analysis of high-resolution directional Compton profiles and two-dimensional angular correlation of positron annihilation experimental data has been performed by studying both a directional anisotropy of measured spectra and reconstructed densities. The results were compared with theoretical fully-relativistic augmented plane-wave calculations

X. F. Wang, P. Vasilopoulos

We study spin transport of holes through stubless or stubbed waveguides modulated periodically by diluted magnetic semiconductor (DMS) sections of width b1 . Injected holes of up (down) spin feel a periodically modulated barrier (well) potential in the DMS sections and have different transmission (T) coefficients. T oscillates with b1 for spin-down and decre

Qi Li, Yong Chen, Ying Hai Wang

We study the critical features of coupling parameter in the synchronization of neural networks with diluted synapses. Based on simulations, the exponential decay form is observed in the extreme case of global coupling among subsystems and fully linking in each network: there exists maximum and minimum of the critical coupling intensity for synchronization in

K. Zieleniec, K. Wojcik, M. Milata, J. Kapusta

The results of the X-ray, microscopic, magnetic, and dielectric measurements performed for PFN single crystals and ceramic samples are presented. The influence of the technological conditions on selected physical properties of the materials examined is shown.

Balázs Dóra, Kazumi Maki, Attila Virosztek

We consider the effect of imperfect nesting in quasi-one dimensional unconventional density waves. The phase diagram is very close to those in a conventional DW. The linear and non-linear aspects of the electric conductivity are discussed. At T=0 the frequency dependent electric conductivity develops a small dip at low frequencies. The threshold electric fie

V. Braude, A. Stern

Motivated by recent transport and magnetization measurements in BSCCO samples [B. Khaykovich et. al., Phys. Rev. B 61, R9261 (2000)], we present a simple macroscopic model describing effects of inhomogeneous current distribution and shear in a layered superconductor. Parameters of the model are deduced from a microscopic calculation. Our model accounts for t

T. Aoyama, K. Ishikawa, N. Maeda

The physical properties of striped Hall state in the presence of an external unidirectional periodic potential is investigated. The study of searching the optimal orientation of the state is reported for the state at filling factor $ν=2+1/2$ and for the state at higher Landau levels at $l+1/2$ where $l=3,4,5,6,7,8$. It is predicted that two phases of the ori

Yong Chen, Ying Hai Wang, Kong Qing Yang

The average length and average relaxation time of attractors in sequence processing neural networks are investigated. The simulation results show that a critical point of $α$, the loading ratio, is found. Below the turning point, the average length is equal to the number of stored patterns; conversely, the ratio of length and numbers of stored patterns, grow

A. Tsukada, T. Greibe, M. Naito

The lanthanum copper oxide, La2CuO4, which is an end member of the prototype high-Tc superconductors (La,Sr)2CuO4 and (La,Ba)2CuO4, crystallizes in the &#34;K2NiF4&#34; structure in high-temperature bulk synthesis. The crystal chemistry, however, predicts that La2CuO4 is at the borderline of the K2NiF4 stability and that it can crystallize in the Nd2CuO4 str

Damian H. Zanette

We report numerical simulations of a strongly biased diffusion process on a one-dimensional substrate with directed shortcuts between randomly chosen sites, i.e. with a small-world-like structure. We find that, unlike many other dynamical phenomena on small-world networks, this process exhibits non-monotonic dependence on the density of shortcuts. Specifical

Yong Chen, Ying Hai Wang, Kong Qing Yang

The parallel dynamics is given in the case of neural networks with separable coupling through starting from Coolen-Sherrington (CS) theory. It is shown that this retrieve dynamics as is the case of sequential evolution in the postulate of away from saturation and finite temperature. The finite-size effects is governed by a homogeneous Markov process, which d

Federico Becca, Frederic Mila, Didier Poilblanc

We investigate a model of a frustrated spin-1/2 Heisenberg chain coupled to adiabatic phonons with a general form of magnetoelastic coupling. For large enough frustration and lattice coupling a new tetramerised phase with three different bond lengths is found. We argue that the zig-zag spin-1/2 chain LiV$_2$O$_5$ might be a good candidate to observe such a p

M. Naito, A. Tsukada, T. Greibe, H. Sato

The lanthanide (Ln) copper oxides of the general chemical formula Ln2CuO4 take two different crystal structures: K2NiF4(T) and Nd2CuO4(T&#39;). La2CuO4 takes the T structure by high-temperature bulk processes. The &#34;thermal expansion mismatch&#34; between the La-O and Cu-O bonds predicts that the T&#39; phase of La2CuO4 can be stabilized at synthesis temp

J. E. Hoffman, K. McElroy, D. -H. Lee, K. M Lang

Scanning tunneling spectroscopy of the high-Tc superconductor Bi2Sr2CaCu2O8+d reveals weak, incommensurate, spatial modulations in the tunneling conductance. Images of these energy-dependent modulations are Fourier analyzed to yield the dispersion of their wavevectors. Comparison of the dispersions with photoemission spectroscopy data indicates that quasipar

J. J. Lin, T. J. Li, Y. L. Zhong

The behavior of the electron dephasing time near zero temperature, $τ_ϕ^0$, has recently attracted vigorous attention. This renewed interest is primarily concerned with whether $τ_ϕ^0$ should reach a finite or an infinite value as $T \to$ 0. While it is accepted that $τ_ϕ^0$ should diverge if there exists only electron-electron (electron-phonon) scattering,

Seiji Miyoshi, Hiro-Fumi Yanai, Masato Okada

The synapses of real neural systems seem to have delays. Therefore, it is worthwhile to analyze associative memory models with delayed synapses. Thus, a sequential associative memory model with delayed synapses is discussed, where a discrete synchronous updating rule and a correlation learning rule are employed. Its dynamic properties are analyzed by the sta

S. V. Kravchenko, A. A. Shashkin, V. T. Dolgopolov

In a recent Letter (PRL 88, 196404 (2002)), the effective g-factor and the effective mass have been studied by Pudalov et al. in a dilute 2D electron system in silicon. The authors contrast their data with the data obtained by our group (Shashkin et al., PRL 87, 086801 (2001)) and claim that the spin susceptibility &#34;increases gradually with decreasing de

W. de Vries, W. van Breugel, A. Quirrenbach

The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large galaxies are formed in a hierarchical way by multiple merger events, radio galaxies at low redshift represent

N. J. Shaviv, G. Shaviv

The exact ionization state of Be7 in the solar core is crucial for the precise prediction of the solar B8 neutrino flux. We therefore examine the effect of pressure ionization on the ionization state of Be7 and all elements with 12 >= Z >= 4. We show that under the conditions prevailing in the solar core, one has to consider the effect of the nearest neighbo

Nir J. Shaviv

The short term variability of the Galactic cosmic ray flux (CRF) reaching Earth has been previously associated with variations in the global low altitude cloud cover. This CRF variability arises from changes in the solar wind strength. However, cosmic ray variability also arises intrinsically from variable activity of and motion through the Milky Way. Thus,

Stuart L. Shapiro, Masaru Shibata

The collapse of a uniformaly rotating, supermassive star (SMS) to a supermassive black hole (SMBH) has been followed recently by means of hydrodynamic simulations in full general relativity. The initial SMS of arbitrary mass M in these simulations rotates uniformly at the mass--shedding limit and is marginally unstable to radial collapse. The final black hol

Neal Dalal, Benjamin F. Lane

Interferometers offer multiple methods for studying microlensing events and determining the properties of the lenses. We investigate the study of microlensing events with optical interferometers, focusing on narrow-angle astrometry, visibility, and closure phase. After introducing the basics of microlensing and interferometry, we derive expressions for the s

Christopher J. Deloye, Lars Bildsten

We assess the impact of the trace element Ne-22 on the cooling and seismology of a liquid C/O white dwarf (WD). Due to this element&#39;s neutron excess, it sinks towards the interior as the liquid WD cools. The gravitational energy released slows the WD&#39;s cooling by 0.5-1.6 Gyr. In addition the Ne-22 abundance gradient changes the periods of the high ra

A. C. Andersen, S. Hoefner, R. Gautschy-Loidl

We present self-consistent dynamical models for dust driven winds of carbon-rich AGB stars. The models are based on the coupled system of frequency-dependent radiation hydrodynamics and time-dependent dust formation. We investigate in detail how the wind properties of the models are influenced by the micro-physical properties of the dust grains that enter as

K. Iwasawa, P. R. Maloney, A. C. Fabian

A short Chandra ACIS-S observation of the Seyfert 2 galaxy IC 2560, which hosts a luminous nuclear water megamaser, shows: 1) the X-ray emission is extended; 2) the X-ray spectrum shows emission features in the soft (E<2 keV) X-ray band; this is the major component of the extended emission; and 3) a very strong (EW~3.6 keV) iron K line at 6.4 keV on a flat c

Aake Nordlund, Paolo Padoan

Supersonic turbulence fragments the interstellar medium into dense sheets, filaments, cores and large low density voids. The turbulence is driven on large scales, probably predominantly by supernovae. The scaling properties of supersonic turbulence are well described by a new analytical theory. The distribution of proto-stellar core masses depends primarily

Simon J. Lilly, C. Marcella Carollo, Alan N. Stockton

A brief review concludes that there is now good overall agreement between theoretical estimates of the energy associated with the production of the observed metal content of the Universe and the observed extragalactic background light. In addition the overall form of the star-formation history over 0 < z < 5 is reasonably well constrained. The study of emiss

Emilio Spedicato, Elena Bodon, Antonino Del Popolo, Nezam Mahdavi-Amiri

ABS methods are a large class of methods, based upon the Egervary rank reducing algebraic process, first introduced in 1984 by Abaffy, Broyden and Spedicato for solving linear algebraic systems, and later extended to nonlinear algebraic equations, to optimization problems and other fields; software based upon ABS methods is now under development. Current ABS

B. Smalley, R. B. Gardiner, F. Kupka, M. S. Bessell

In previous work, Gardiner et al. (1999) found evidence for a discrepancy between the Teff obtained from Balmer lines with that from photometry and fundamental values for A-type stars. An investigation into this anomaly is presented using Balmer line profiles of stars in binary system with fundamental values of both Teff and log g. A revision of the fundamen

Thomas H. Puzia, Roberto P. Saglia, Markus Kissler-Patig, Claudia Maraston

We present a comprehensive spectroscopic study of the integrated light of metal-rich Galactic globular clusters and the stellar population in the Galactic bulge. We measure line indices which are defined by the Lick standard system and compare index strengths of the clusters and Galactic bulge. Both metal-rich globular clusters and the bulge are similar in m

Carles Badenes, Eduardo Bravo

We present the first results from an ongoing work aimed to use supernovae remnants to discriminate among different type Ia supernovae explosion models. We have computed the hydrodynamic interaction of supernova ejecta with the interstellar medium, obtaining the evolution of the density, temperature and ionization structure of the remnant. We have used ejecta

V. Buat, T. T. Takeuchi, A. Boselli, D. Burgarella

Before the end of 2002 will be launched the GALEX satellite (a NASA/SMEX project) which will observe all the sky in Ultraviolet (UV) through filters at 1500 and 2300 A down to m(AB) 21. In 2004 will be launched the ASTRO-F satellite which will perform an all sky survey at Far-Infrared (FIR) wavelengths. The cross-correlation of both surveys will lead to very

Z. -Q. Shen, J. M. Moran, K. I. Kellermann

We report on a VLBA imaging study of the nearby bright southern blazar PKS 1921 - 293 (OV - 236). High resolution VLBA observations, made at four frequencies (5, 12, 15, and 43 GHz) over the period 1994 - 2000, have revealed a strongly curved jet extending out to about 50 parsecs from the presumed central engine. Two epoch VLBA observations, each simultaneou

T. Kato, R. Ishioka, M. Uemura

We examined the VSNET light curve of the unusual SU UMa-type dwarf nova V503 Cyg which is known to show a short (89 d) supercycle length and exceptionally small (a few) normal outbursts within a supercycle. In 1999-2000, V503 Cyg displayed frequent normal outbursts with typical recurrence times of 7-9 d. The behavior during this period is characteristic to a

Giovanni Amelino-Camelia

Among the possible explanations for the puzzling observations of cosmic rays above the GZK cutoff there is growing interest in the ones that represent kinematical solutions, based either on general formulations of particle physics with small violations of Lorentz symmetry or on a quantum-gravity-motivated scheme for the breakup of Lorentz symmetry. An unappe

Feryal Ozel, Dimitrios Psaltis

The line profiles from rotating neutron stars are affected by a number of relativistic processes such as Doppler boosts, strong self-lensing, frame-dragging, and the differential gravitational redshift arising from the stellar oblateness. In this Letter, we calculate line profiles taking into account the first two effects, which is accurate for rotation rate

Syksy Rasanen

This is an introduction to the ekpyrotic scenario, with an emphasis on the two contexts of brane cosmology and primordial universe scenarios. A self-contained introduction to brane cosmology and a qualitative overview and comparison of the inflationary, pre-big bang and ekpyrotic scenarios are given as background. The ekpyrotic scenario is then presented in

Paulo F. Bedaque, Aurel Bulgac, Gautam Rupak

It was recently shown (A. Bulgac. Phys. Rev. Lett. {\bf 89}, 050402 (2002)) that an entirely new class of quantum liquids with widely tunable properties could be manufactured from bosons (boselets), fermions (fermilets) and their mixtures (ferbolets) by controlling their interaction properties by the means of a Feshbach resonance. We extend the previous mean

J. A. Collins, J. M. Shull, M. L. Giroux

Using archival Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope (HST) data, we have assembled a survey of eight sightlines through high-velocity cloud Complex C. Abundances of the observed ion species vary significantly for these sightlines, indicating that Complex C is not well characterized by a single metallicity. Reliable metallic

Andrei M. Beloborodov

Fireballs of gamma-ray bursts are partially made of free neutrons. Their presence crucially changes the mechanism of the fireball deceleration by an external medium. At late stages of the explosion, neutrons fully decouple from ions and coast with a constant Lorentz factor Γ_n. As the ion fireball decelerates, the neutrons form a leading front. This front gr

James Y-K. Cho, Kristen Menou, Brad Hansen, Sara Seager

High-resolution atmospheric flow simulations of the tidally-locked extrasolar giant planet, HD 209458b, show large-scale spatio-temporal variability. This is in contrast to the simple, permanent day/night (i.e., hot/cold) picture. The planet&#39;s global circulation is characterized by a polar vortex in motion around each pole and a banded structure correspo

Brendon Lovett, John H. Reina, Ahsan Nazir, Beeneet Kothari

Resonant energy transfer mechanisms have been observed in the sensitized luminescence of solids, in quantum dots and in molecular nanostructures, and they also play a central role in light harvesting processes in photosynthetic organisms. We demonstrate that such mechanisms, together with the exciton-exciton binding energy shift typical of these nanostructur

Ralph M. Kaufmann

Motivated by string topology and the arc operad, we introduce the notion of quasi-operads and consider four (quasi)-operads which are different varieties of the operad of cacti. These are cacti without local zeros (or spines) and cacti proper as well as both varieties with fixed constant size one of the constituting loops. Using the recognition principle of

Aaron D. Lewis, David A. Buote, John T. Stocke

We have used a high resolution Chandra observation to examine the core mass distribution of the unusually regular cD cluster Abell 2029. This system is especially well-suited for analysis of its mass distribution under the assumption of hydrostatic equilibrium: it exhibits an undisturbed X-ray morphology and a single-phase ICM. We estimate the total mass, an

Ralph M Kaufmann, Muriel Livernet, RC Penner

Several topological and homological operads based on families of projectively weighted arcs in bounded surfaces are introduced and studied. The spaces underlying the basic operad are identified with open subsets of a compactification due to Penner of a space closely related to Riemann&#39;s moduli space. Algebras over these operads are shown to be Batalin-Vi

M. Cannoni, St. Kolb, O. Panella

The cross section for the reaction $e^{-}e^{-} \to \ell^-\ell^-$ ($\ell=μ,τ$) is calculated in models with heavy Majorana neutrinos mediating lepton number violating amplitudes at the loop level. The contributing four-point functions are evaluated exactly (numerically) taking into account the full propagator dependence on external momenta, thereby extending

Y. Uchiyama, F. A. Aharonian, T. Takahashi

We present morphological and spectroscopic studies of the northwest rim of the supernova remnant RX J1713.7-3946 based on observations by the Chandra X-ray observatory. We found a complex network of nonthermal (synchrotron) X-ray filaments, as well as a 'void' type structure -- a dim region of a circular shape -- in the northwest rim. It is remarkable that d

K. Zarembo

A semiclassical string description is given for correlators of Wilson loops with local operators in N=4 SYM theory in the regime when operators carry parametrically large R-charge. The OPE coefficients of the circular Wilson loop in chiral primary operators are computed to all orders in the alpha&#39; expansion in AdS_5xS^5 string theory. The results agree w

C. Maraston, L. Greggio, A. Renzini, S. Ortolani

Synthetic Lick indices (e.g. Mg_2, Fe, etc.) of Simple Stellar Population (SSP) models are calibrated for the first time up to solar metallicity with a sample of Milky Way globular clusters (GCs) which includes the metal rich GCs of the Galactic bulge. This metallicity range is relevant to elliptical galaxies. It is shown that the Bulge GCs and integrated li

Y. G. Zhao, S. R. Shinde, S. B. Ogale, J. Higgins

Ferromagnetism is observed at and above room temperature in pulsed laser deposited epitaxial films of Co-doped Ti-based oxide perovskite (La1-xSrxTiO3-d). The system has the characteristics of an intrinsic diluted magnetic semiconductor (metal) at low concentrations (<~ 2 %), but develops inhomogeneity at higher cobalt concentrations. The films range from be

Douglas Fregolente, Mauro D. Tonasse

Recently has been showed that models which consider self-interacting particles as dark matter candidates can be able to account all the discrepancies between N-body simulations and astronomical observations of the galactic structure. In the present work we show that the 3-3-1-electroweak model can provide a realistic candidate to this kind of dark matter. Th

Yves Brihaye, Betti Hartmann

Considering a Skyrme model with a peculiar gauging of the symmetry, monopole-like solutions exist through a topological lower bound. However, it was recently shown that these objects cannot form bound states in the limit of vanishing Skyrme coupling. Here we consider these monopoles in scalar-tensor gravity. A numerical study of the equations reveals that ne

C. J. Fewster, T. A. Roman

For the quantised, massless, minimally coupled real scalar field in four-dimensional Minkowski space, we show (by an explicit construction) that weighted averages of the null-contracted stress-energy tensor along null geodesics are unbounded from below on the class of Hadamard states. Thus there are no quantum inequalities along null geodesics in four-dimens

Dmitri V. Alekseevsky, Vicente Cortés, Chandrashekar Devchand

Let M be a manifold with Grassmann structure, i.e. with an isomorphism of the cotangent bundle T^*M\cong E\otimes H with the tensor product of two vector bundles E and H. We define the notion of a half-flat connection \nabla^W in a vector bundle W\to M as a connection whose curvature F\in S^2E\otimes\wedge^2 H\otimes W \subset\wedge^2 T^*M\otimes W. Under ap

Garry Bowen

In Shannon information theory the capacity of a memoryless communication channel cannot be increased by the use of feedback. In quantum information theory the no-cloning theorem means that noiseless copying and feedback of quantum information cannot be achieved. In this paper, quantum feedback is defined as the unlimited use of a noiseless quantum channel fr

Andrzej Marecki, Peter D. Barthel, Antonis Polatidis, Izabela Owsianik

AGN with the so-called `double-double' radio structure have been interpreted as restarted AGN where the inner structure is a manifestation of a new phase of activity which happened to begin before the outer radio lobes resulting from the previous one had faded completely. The radio galaxy 1245+676 is an extreme example of such a double-double object - its ou

D. S. Petrov

We discuss 3-body processes in ultracold two-component Fermi gases with short-range intercomponent interaction characterized by a large and positive scattering length $a$. It is found that in most cases the probability of 3-body recombination is a universal function of the mass ratio and $a$, and is independent of short-range physics. We also calculate the s

Bo-Qiang Ma, Ivan Schmidt, Jian-Jun Yang

We investigate the spin structure of the nucleon in an extended Jaffe-Lipkin quark model. In addition to the conventional $3q$ structure, different $(3q)(Q\bar{Q})$ admixtures in the nucleon wavefunction are also taken into account. The contributions to the nucleon spin from various components of the nucleon wavefunction are discussed. The effect due to the

Bo-Qiang Ma, Ivan Schmidt, Jian-Jun Yang

The azimuthal spin asymmetries for pion production in semi-inclusive deep inelastic scattering of unpolarized charged lepton beams on longitudinally polarized nucleon targets, are reanalyzed by taking into account an important sign correction to previous formulas. It is found that different approaches of distribution functions and fragmentation functions may

K. Urbanowski

The Bell--Steinberger relation is analyzed. The questionable points of the standard derivation of this relation are discussed. It is shown that the use of a more accurate approximation than the one usually used in the derivation of this relation can lead to corrections to the right hand side of the standard Bell--Steinberger relation.

S. K. Roushon

In this paper we show that the fibered isomorphism conjecture of Farrell and Jones corresponding to the stable topological pseudoisotopy functor is true for the fundamental groups of a large class of complex manifolds. A consequence of this result is that the Whitehead group, reduced projective class groups and the negative K-groups of the fundamental group