May 2003 arXiv papers — page 15

Artur Avila

Recently, Xavier Buff and Arnaud Cheritat have provided an elegant proof of the existence of quadratic Siegel disks with smooth boundary. In this short note, we show how results of Yoccoz and Risler can be used to conclude the same result. Our proof is a small modification of the argument given by Buff and Cheritat.

Carmi Merimovich

We present a modification to the Prikry on Extenders forcing notion allowing the blow up of the power set of a large cardinal, change its cofinality to omega without adding bounded subsets, working directly from arbitrary extender (e.g., n-huge extender). Using this forcing, starting from a superstrong cardinal, we construct a model in which the added Prikry

A. Dimca, S. Papadima

We show that the equivariant chain complex associated to a minimal CW-structure X on the complement M(A) of a hyperplane arrangement A, is independent of X. When A is a sufficiently general linear section of an aspheric arrangement, we explain a new way for computing the twisted homology of M(A).

Peter Koepke, Ralf Schindler

We prove that every homogeneously Souslin set is coanalytic provided that either (a) 0^long does not exist or else (b) V=K where K is the core model below a μ-measurable cardinal.

Georgi Popov

We consider Gevrey perturbations $H$ of a completely integrable Gevrey Hamiltonian $H_0$. Given a Cantor set $Ω_κ$ defined by a Diophantine condition, we find a family of KAM invariant tori of $H$ with frequencies $ω\in Ω_κ$ which is Gevrey smooth in a Whitney sense. Moreover, we obtain a symplectic Gevrey normal form of the Hamiltonian in a neighborhood of

Eui Chul Kim

In [5] Herzlich proved a new positive mass theorem for Riemannian 3-manifolds $(N, g)$ whose mean curvature of the boundary allows some positivity. In this paper we study what happens to the limit case of the theorem when, at a point of the boundary, the smallest positive eigenvalue of the Dirac operator of the boundary is strictly larger than one-half of th

Laurent Bartholdi, Balint Virag

We answer an open question of Grigorchuk and Zuk about amenability using random walks. Our results separate the class of amenable groups from the closure of subexponentially growing groups under the operations of group extension and direct limits; these classes are separated even within the realm of finitely presented groups.

Bhupinder Singh Anand

In 1995, David Chalmers opined as implausible that there may be parts of our arithmetical competence that no sound formal system could ever duplicate. We prove that the recursive number-theoretic relation x=Sb(y 19|Z(y)) - which is algorithmically verifiable since Goedel's recursive function Sb(y 19|Z(y)) is Turing-computable - cannot be "duplicated&

Ulrich Kraehmer

The Hopf algebra generated by the l-functionals on the quantum double C_q[G] \bowtie C_q[G] is considered, where C_q[G] is the coordinate algebra of a standard quantum group and q is not a root of unity. It is shown to be isomorphic to C_q[G]^op \bowtie U_q(g). This was conjectured by T. Hodges in [Ho]. As an algebra it can be embedded into U_q(g) \otimes U_

Laurent Bartholdi

This note describes the first example of a group that is amenable, but cannot be obtained by subgroups, quotients, extensions and direct limits from the class of groups locally of subexponential growth. It has a balanced presentation \[Δ= < b,t|[b,t^2]b^{-1},[[[b,t^{-1}],b],b]>.\] I show that it acts transitively on a 3-regular tree, and that $Γ=< b,b^{t^{-1

T. Padmanabhan, Apoorva Patel

The principle of equivalence provides a description of gravity in terms of the metric tensor and determines how gravity affects the light cone structure of the space-time. This, in turn, leads to the existence of observers (in any space-time) who do not have access to regions of space-time bounded by horizons. To take into account this generic possibility, i

T. Banks

The Cartan-Penrose (CP) equation is interpreted as a connection between a spinor at a point in spacetime, and a pair of holographic screens on which the information at that point may be projected. Local SUSY is thus given a physical interpretation in terms of the ambiguity of the choice of holographic screen implicit in the work of Bousso. The classical CP e

M. V. Cougo-Pinto, J. F. M. Mendes, C. Farina

In a related paper we have obtained that the effective action for a kappa-deformed quantum field theory has a real and an imaginary part. The real part is half the sum of the kappa-deformed zero mode frequencies, while the imaginary part is proportional to the sum of the squares of the zero mode frequencies, being proportional to the inverse of kappa. Here w

M. V. Cougo-Pinto, J. F. M. Mendes, C. Farina

In a quantum field with spacetime invariance governed by the Poincare algebra the one-loop effective action is equal to the sum of zero modes frequencies, which is the vacuum energy of the field. The first Casimir invariant of the Poincare algebra provides the proper time Hamiltonian in Schwinger&#39;s proper time representation of the effective action. We c

Raphael Bousso, Eanna E. Flanagan, Donald Marolf

The generalized covariant entropy bound is the conjecture that the entropy of the matter present on any non-expanding null hypersurface L will not exceed the difference between the areas, in Planck units, of the initial and final spatial 2-surfaces bounding L. The generalized Bekenstein bound is a special case which states that the entropy of a weakly gravit

J. Besprosvany

A coupling-constant definition is given based on the compositeness property of some particle states with respect to the elementary states of other particles. It is applied in the context of the vector-spin-1/2-particle interaction vertices of a field theory, and the standard model. The definition reproduces Weinberg&#39;s angle in a grand-unified theory. One

A. Gardestig, A. P. Szczepaniak, J. T. Londergan

A model for deeply virtual Compton scattering, based on analytical light-cone hadron wave functions is presented and studied at energies currently accessible at Jefferson Laboratory, DESY, and beyond. It is shown that perpendicular vector components play an important role at Q^2 < 10 GeV^2 and that the meson-exchange diagrams are important at all energies. T

G. Battistoni, A. Ferrari, T. Montaruli, P. R. Sala

The atmospheric neutrino flux calculated with FLUKA was originally limited to 100-200 GeV for statistical reasons. In order to make it available for the analysis of high energy events, like upward through-going muons detected by neutrino telescopes, we have extended the calculation so to provide a reliable neutrino yield per primary nucleon up to about 10**6

Savely G. Karshenboim

This review is devoted to precision physics of simple atoms. The atoms can essentially be described in the framework of quantum electrodynamics (QED), however, the energy levels are also affected by the effects of the strong interaction due to the nuclear structure. We pay special attention to QED tests based on studies of simple atoms and consider the influ

Robert Harlander, William Kilgore

New techniques developed in connection with the NNLO corrections to the Higgs production rate at hadron colliders and some recent applications are reviewed.

O. Mena

We update a recent work devoted to resolve the degeneracies that appear in the simultaneous extraction of $θ_{13}$ and $δ$ at future Neutrino Factories (NF, that exploit the \emph{golden} channels, i.e. $ν_e\toν_μ$ ($\barν_e\to\barν_μ$)) and Superbeam experiments (SB, that measure the $ν_μ\toν_e$ ($\barν_μ\to\barν_e$) transitions). We consider the neutrino f

Marco Cirelli

Models with extra space dimensions naturally provide for the existence of fermions that propagate in them. These are seen in 4D as an infinite tower of sterile neutrinos possibly mixed with the Standard Model ones. We consider the effect of such a mixing in the context of core collapse supernova physics. We show that the potentially dramatic modifications to

Charles A. Nelson

This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model&#39;s four decay helicity amplitudes, A_{SM}, and also the amplitudes A_{+} in the case of an additional t_R --> b_L tensorial coupling of relative strength Λ_{+} =E_W /2 = 53 GeV. Such an additional electroweak coupling w

Thomas Schaefer

In these lectures we provide an introduction to the theory of QCD at very high baryon density. We begin with a review of some aspects of quantum many-body system that are relevant in the QCD context. We also provide a brief review of QCD and its symmetries. The main part of these lectures is devoted to the phenomenon of color superconductivity. We discuss th

G. Grignani, D. Marmottini, P. Sodano

The low energy mass spectrum of QCD in the large $N_C$ limit is computed. The low-lying states in the meson spectrum are explicitly evaluated up to the fourth order in the strong coupling perturbative expansion. The &#39;t Hooft limit is smooth and the meson masses are in very good agreement with the experimental values.

A. Korn

First charm physics results from the CDF and D0 experiments at the Tevatron Run II are presented. With the addition of the Secondary Vertex Trigger CDF has become a competitive charm experiment.

The OPAL collaboration, G. Abbiendi

A search for pair-produced leptoquarks is performed using e+e- collision events collected by the OPAL detector at LEP at centre-of-mass energies between 189 and 209 GeV. The data sample corresponds to a total integrated luminosity of 596 pb^-1. The leptoquarks are assumed to be produced via couplings to the photon and the Z0. For a given search channel only

Kai-C. Voss

At the HERA collider the experiments H1 and ZEUS have studied the exclusive production of vector mesons over a wide kinematical range. A selection of recent measurements of the cross sections has been presented at Moriond QCD 2003.

Aafke Christine Kraan

This talk reviews the searches for sbottom and stop quarks at LEP. The existing results of the four LEP experiments for sbottom and stop quarks searches are summarized. Furthermore, new mass limits on stable hadronizing squarks and gluinos are derived by combining Z-lineshape constraints with direct searches for squarks and gluinos using ALEPH data. All limi

A. Bertolin

Charm in electron proton collisions is a particularly large and interesting field. For this summary two topics particularly relevant for HERA have been selected. First the study of inelastic J/psi production in both the photoproduction and the electroproduction regime, study still needed to clarify the Jψproduction mechanisms. Second the analysis of D* photo

M. N. Achasov, K. I. Beloborodov, A. V. Berdyugin, A. G. Bogdanchikov

The cross section of the process $e^+e^-\to π^+π^-π^0$ was measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the energy region $\sqrt[]{s}$ below 980 MeV. This measurement was based on about $1.2 \times 10^6$ selected events. The obtained cross section was analyzed together with the SND and DM2 data in the energy region $

The BABAR Collaboration, B. Aubert

We present our first study of the time-dependent CP-violating asymmetry in B0 --> J/psi pi0 decays using e^+e^- annihilation data collected with the BABAR detector at the Y(4S) resonance during the years 1999--2002 at the PEP-II asymmetric-energy B Factory at SLAC. With about 88 million B Bbar pairs, our preliminary results for the coefficients of the cosine

Gilad Gour, A. J. M. Medved

In this letter, we discuss how thermal fluctuations can effect the stability of (generally) charged black holes when close to certain critical points. Our novel treatment utilizes the black hole area spectrum (which is, for definiteness, taken to be evenly spaced) and makes an important distinction between fixed and fluctuating charge systems (with these bei

John Swain

Recent attempts to resolve the ambiguity in the loop quantum gravity description of the quantization of area has led to the idea that j=1 edges of spin-networks dominate in their contribution to black hole areas as opposed to j=1/2 which would naively be expected. This suggests that the true gauge group involved might be SO(3) rather than SU(2) with attendan

Vishnu Jejjala, Robert G. Leigh, Djordje Minic

Deconstruction provides a novel way of dealing with the notoriously difficult ultraviolet problems of four-dimensional gravity. This approach also naturally leads to a new perspective on the holographic principle, tying it to the fundamental requirements of unitarity and diffeomorphism invariance, as well as to a new viewpoint on the cosmological constant pr

Erin Bonning, Pedro Marronetti, David Neilsen, Richard Matzner

An orbiting black hole binary will generate strong gravitational radiation signatures, making these binaries important candidates for detection in gravitational wave observatories. The gravitational radiation is characterized by the orbital parameters, including the frequency and separation at the inner-most stable circular orbit (ISCO). One approach to esti

S. Krasnikov

A very brief and popular account of the time machine problem.

Martin Bojowald

In physical theories, boundary or initial conditions play the role of selecting special situations which can be described by a theory with its general laws. Cosmology has long been suspected to be different in that its fundamental theory should explain the fact that we can observe only one particular realization. This is not realized, however, in the classic

Jun&#39;ichi Yokoyama

Some issues of the cosmological constant or dark energy are briefly reviewed. There are an increasing number of observations that constrain the equation of state of dark energy more stringently and favor the time-independent cosmological constant. Then a plausible model of dark energy would be a theory with degenerate perturbative vacua in which its origin i

Chia-Ren Hu

Xu et al. observed enhanced Nernst effect and Iguchi et al. observed patched diamagnetism, both well above $T_c$ in underdoped high-$T_c$ superconductors (HTSCs). A new mechanism is proposed here, which seems to naturally explain, at least qualitatively, these observations, as well as the d-wave nature and continuity of pseudogap and pairing gap, the tunneli

James P. Donley, David R. Heine, David T. Wu

We present a theory for the equilibrium structure of polyelectrolyte solutions. The main element is a simple, new optimization scheme that allows theories such as the random phase approximation (RPA) to handle the harsh repulsive forces present in such systems. Comparison is made with data from recent neutron scattering experiments of randomly charged, hydro

Joaquin Garcia, Gloria Subias

In a recent published paper [Phys. Rev. B 64, 195133 (2001)], Zimmermann et al. present a systematic x-ray scattering study of charge and orbital ordering phenomena in the Pr1-xCaxMnO3 series with x= 0.25, 0.4 and 0.5. They propose that for Ca concentrations x=0.4 and 0.5, the appearance of (0, k+1/2, 0) reflections are originated by the orbital ordering of

R. Merlin

The problem of imaging for a nearly-perfect lens, namely, a slab of a left-handed material with refractive index n = -(1-sigma)^1/2 is solved analytically for |sigma| << 1. The electromagnetic field behavior is determined largely by singularities arising from the excitation of surface polaritons with wavevector q -->oo. Depending on the sign of sigma, the ne

Mario Freamat, K. -W. Ng

Ag/BSCCO and Fe/Ag/BSCCO planar tunnel junctions were constructed in order to study experimentally the effect of an exchange potential on the spin polarized current transported through Andreev bound states appearing at the interface with a superconductor with broken time reversal pairing symmetry. The zero bias conductance peak (ZBCP) resulting from the Andr

V. Gurarie, J. T. Chalker

We consider classical normal modes and non-interacting bosonic excitations in disordered systems. We emphasise generic aspects of such problems and parallels with disordered, non-interacting systems of fermions, and discuss in particular the relevance for bosonic excitations of symmetry classes known in the fermionic context. We also stress important differe

P. Fröbrich, P. J. Kuntz

In using the spectral theorem of many-body Green&#39;s function theory in order to relate correlations to commutator Green&#39;s functions, it is necessary in the standard procedure to consider the anti-commutator Green&#39;s functions as well whenever the matrix governing the equations of motion for the commutator Green&#39;s functions has zero eigenvalues.

S. Mossa, G. Tarjus

We propose a method to determine the locally preferred structure of model liquids. This latter is obtained numerically as the global minimum of the effective energy surface of clusters formed by small numbers of particles embedded in a liquid-like environment. The effective energy is the sum of the intra-cluster interaction potential and of an external field

S. Bumble

An In Silico model to relate the properties of proteins to the structure, sequence, function and evolutionary history of proteins is shown. The derived ideal sequences for amino acid residues in proteins can then be considered as attractors for structures of actual protein families and their functions. Hopfield networks1 can then act as GCMs (General Content

M. J. Calderon, A. J. Millis, K. H. Ahn

Theoretical and computational results are presented clarifying the role of long-ranged strain interactions in determining the charge and orbital ordering in colossal magnetoresistance manganites. The strain energy contribution is found to be of order 20-30 meV/Mn and in particular stabilizes the anomalous &#39;zig-zag chain&#39; order observed in many half-d

T. Vorrath, T. Brandes

We calculate the stationary current through two double quantum dots which are interacting via a common phonon environment. Numerical and analytical solutions of a master equation in the stationary limit show that the current can be increased as well as decreased due to a dissipation mediated interaction. This effect is closely related to collective, spontane

T. Jarlborg

Band calculations show that a stripe-like anti-ferromagnetic spin wave is enforced by a &#39;half-breathing&#39; phonon distortion within the CuO plane of HgBa_2CuO_4. This spin-phonon coupling is increased further by shear distortion and by increased distance between Cu and apical oxygens. The effects from spin-phonon coupling are consistent with many obser

Cristian Predescu, Dubravko Sabo, J. D. Doll

The reweighted random series techniques provide finite-dimensional approximations to the quantum density matrix of a physical system that have fast asymptotic convergence. We study two special reweighted techniques that are based upon the Levy-Ciesielski and Wiener-Fourier series, respectively. In agreement with the theoretical predictions, we demonstrate by

T. Fukumura, Y. Yamada, H. Toyosaki, T. Hasegawa

A review is given for the recent progress of research in the field of oxide-based diluted magnetic semiconductor (DMS), which was triggered by combinatorial discovery of transparent ferromagnet. The possible advantages of oxide semiconductor as a host of DMS are described in comparison with conventional compound semiconductors. Limits and problems for identi

D. McPeake, F. T. Vasko, E. P. O&#39;Reilly

We investigate coherent nonlinear dynamics of 2D electrons under ultrafast intersubband excitation by mid-IR pulses. We include the effects of relaxation and dephasing, both homogeneous and inhomogeneous, as well as detuning within a non-Markovian equation to obtain temporal population redistributions. We show how, using a cross-correlation method, the effec

E. O. Kamenetskii

The anapole moments describe the parity-violating parity-odd, time-reversal-even couplings between elementary particles and the electromagnetic (EM) field. Surprisingly, the anapole-like moment properties can be found in certain artificially engineered physical systems. In microwaves, ferrite resonators with multi-resonance magnetostatic-wave (MS-wave) oscil

Pietro Cicuta, Edward J. Stancik, Gerald G. Fuller

We report surface shear rheological measurements on dense insoluble monolayers of micron sized colloidal spheres at the oil/water interface and of the protein $β$-lactoglobulin at the air/water surface. As expected, the elastic modulus shows a changing character in the response, from a viscous liquid towards an elastic solid as the concentration is increased

J. L. Cheng, M. Q. Weng, M. W. Wu

The spin dephasing due to the Rashba spin-orbit coupling, especially its dependence on the direction of the electric field is studied in InAs quantum wire. We find that the spin dephasing is strongly affected by the angle of Rashba effective magnetic field and the applied magnetic field. The nonlinearity in spin dephasing time versus the direction of the ele

Yu. V. Goryunov

Superconducting transition temperature (Tc) and FMR were measured in heterostructure OC/V/Fe, were OC=Fe/Cr/Fe. Giant oscillations of Tc depending on a Cr-thickness were detected. Probable reasons of Tc-oscillation are discussed - periodic cancellation of pair-breacking exchange fields in superconducting V-layer or in fragment Fe/Cr/Fe.

H. Rho, S. L. Cooper, S. Nakatsuji, H. Fukazawa

We use Raman scattering to study spin, charge, and lattice dynamics in various phases of Ca_{2-x}Sr_{x}RuO_{4}. With increasing substitution of Ca by Sr in the range 0 =< x < 0.2, we observe (1) evidence for an increase of the electron-phonon interaction strength, (2) an increased temperature-dependence of the two-magnon energy and linewidth in the antiferro

Jong Soo Lim, M. Y. Choi, Beom Jun Kim

We study resonance behavior of a two-dimensional fully frustrated Josephson-junction array driven by high alternating currents. The signal-to-noise ratio (SNR) is examined as the frequency of the driving current is varied; revealed is a certain frequency range where the SNR is enhanced. Such resonance behavior is explained by considering the dynamic order pa

Tai-Kai Ng

In this paper we generalize slave-boson mean-field theory for $t-J$ model to the time-dependent regime, and derive transport equations for $t-J$ model, both in the normal and superconducting states. By eliminating the boson and constraint fields exactly in the equations of motion we obtain a set of transport equations for fermions which have the same form as

Fusayoshi J. Ohkawa

A theory of Kondo lattices is developed for the t-J model on a square lattice. The spin susceptibility is described in a form consistent with a physical picture of Kondo lattices: Local spin fluctuations at different sites interact with each other by a bare intersite exchange interaction, which is mainly composed of two terms such as the superexchange intera

Z. Konkoli, A. Karlsson, O. Orwar

In the rapidly emerging field of nanotechnology, as well as in biology where chemical reaction phenomena take place in systems with characteristic length scales ranging from micrometer to the nanometer range, understanding of chemical kinetics in restricted geometries is of increasing interest. In particular, there is a need to develop more accurate theoreti

Carl H. Gibson

The first structures were proto-voids formed in the primordial plasma. Viscous and weak turbulence forces balanced gravitational forces when the scale of causal connection at time 30,000 years matched the viscous and turbulent Schwarz scales of hydro-gravitational theory (Gibson 1996). The photon viscosity allows only weak turbulence from the Reynolds number

H. C. Harris, J. Liebert, S. J. Kleinman, A. Nitta

An initial assessment is made of white dwarf and hot subdwarf stars observed in the Sloan Digital Sky Survey. In a small area of sky (190 square degrees), observed much like the full survey will be, 269 white dwarfs and 56 hot subdwarfs are identified spectroscopically where only 44 white dwarfs and 5 hot subdwarfs were known previously. Most are ordinary DA

David Heyrovsky

Observations of microlensing transit events can be used to measure the limb darkening of the lensed star. We discuss the advantages and drawbacks of several microlensing light curve inversion methods. The method of choice in this work is inversion by means of decomposition of the stellar surface brightness profile. We construct an ideal basis by principal co

P. J. Humphrey, G. Fabbiano, M. Elvis, M. J. Church

We present results of a Chandra survey of the ultra-luminous X-ray sources (ULX) in 13 normal galaxies, in which we combine source detection with X-ray flux measurement. 22 ULX were detected, i.e. with L_x > 1 x 10^{39} erg s^{-1} (L_10), and 39 other sources were detected with L_x > 5 x 10^{38} erg s^{-1} (L_5). We also use radial intensity profiles to remo

E. Vesperini, S. E. Zepf

We investigate the role of dissolution of low-concentration clusters due to mass loss through stellar evolution on the evolution of the properties of globular cluster systems (GCSs) in elliptical galaxies. Our simulations show that, for an initial mass-concentration relationship based on that inferred from Galactic globular clusters, dissolution of low-conce

Evan Scannapieco, Robert J. Thacker

Motivated by the observed discrepancy between the strong spatial correlations of Lyman break galaxies (LBGs) and their velocity dispersions, we consider a theoretical model in which these starbursting galaxies are associated with dark matter halos that experience appreciable infall of material. We show using numerical simulation that selecting halos that sub

Subhabrata Majumdar, Joseph J. Mohr

We examine the prospects for measuring the dark energy equation of state parameter w within the context of any uncertain redshift evolution of galaxy cluster structure (building on Majumdar and Mohr, 2003) and show that including the redshift averaged cluster power spectrum, P_cl(k), and direct mass measurements of 100 clusters helps tremendously in reducing

Barton J. Pritzl, Horace A. Smith, Peter B. Stetson, Marcio Catelan

[Abridged] We present the results of a Hubble Space Telescope snapshot program to survey the inner region of the globular cluster NGC 6441 for its variable stars. A total of 57 variable stars was found including 38 RR Lyrae stars, 6 Population II Cepheids, and 12 long period variables. Of the RR Lyrae stars observed in this survey, 26 are pulsating in the fu

S. Seager

The Hubble Space Telescope (HST) detection of an extrasolar planet atmosphere in 2001 was a landmark step forward for the characterization of extrasolar planets. HST detected the trace element sodium, via the neutral atomic resonance doublet at 593 nm, in the transiting extrasolar giant planet HD209458b. In this paper I discuss the significance of this first

S. Seager

The search for extrasolar Earth-like planets is underway. Over 100 extrasolar giant planets are known to orbit nearby sun-like stars, including several in multiple-planet systems. These planetary systems are stepping stones for the search for Earth-like planets; the technology development, observational strategies, and science results can all be applied to E

Daniel De Marco, Pasquale Blasi, Angela V. Olinto

We developed a numerical simulation of the propagation of UHECR in the Cosmic Microwave Background (CMB) and we used it to determine the significance of the GZK feature in the spectrum of UHECR measured by AGASA and HiRes. We find that these two experiments are best fit by two different injection spectra in the region below 10^20 eV and that the error bars a

Robert R. Caldwell, Michael Doran

We perform a detailed comparison of the Wilkinson Microwave Anisotropy Probe (WMAP) measurements of the cosmic microwave background (CMB) temperature and polarization anisotropy with the predictions of quintessence cosmological models of dark energy. We consider a wide range of quintessence models, including: a constant equation-of-state; a simply-parametriz

Tim Huege, Heino Falcke

Extensive air showers (EAS) have been known for over 30 years to emit pulses of radio emission at frequencies from a few to a few hundred MHz, an effect that offers great opportunities for the study of EAS with the next generation of &#34;software radio interferometers&#34; such as LOFAR and LOPES. The details of the emission mechanism, however, remain rathe

Joel H. Kastner, Bruce Balick, Eric G. Blackman, Adam Frank

We report the discovery, by the Chandra X-ray Observatory, of X-ray emission from the bipolar planetary nebula Menzel 3. In Chandra CCD imaging, Mz 3 displays hot (3-6x10^6 K) gas within its twin, coaxial bubbles of optical nebulosity, as well as a compact X-ray source at the position of its central star(s). The brightest diffuse X-ray emission lies along th

J. Woitas, V. S. Tamazian, J. A. Docobo, Ch. Leinert

Based on 14 data points obtained with near-infrared speckle interferometry and covering an almost entire revolution, we present a first visual orbit for the low-mass binary system Gliese 22 AC. The quality of the orbit is largely improved with respect to previous astrometric solutions. The dynamical system mass is 0.592 +- 0.065 solar masses, where the large

A. Malizia, L. Bassani, M. Capalbi, A. C. Fabian

We have used the BeppoSAX satellite to study the broad band (0.5-100 keV) X-ray spectrum of the Seyfert 1.5 galaxy MKN6. The source is characterized by a power law of Gamma=1.7 [+0.08, -0.07] and there is no strong evidence for either a reflection bump or a high energy cut-off. We have detected a narrow iron line at 6.4 keV (rest frame) with an equivalent wi

Fotis Mavromatakis, Panayotis Boumis, Christos D. Goudis

Flux calibrated images of the known supernova remnant G 34.7-0.4 in basic optical emission lines are presented. The low ionization images show a relatively flat flux distribution. The diffuse and patchy morphology of the detected optical emission may indicate the presence of turbulent magnetic fields. Typical observed Halpha+[N II] fluxes are ~8 x 10^{-17} e

K. Fathi, R. F. Peletier

We study HST/NICMOS H-band images of bulges of two equal-sized samples of early- (T(RC3) < 4) and late-type spiral (mainly Sbc-Sc) galaxies matched in outer disk axis ratio. We find that bulges of late-type spirals are more elongated than their counterparts in early-type spirals. Using a KS-test we find that the two distributions are different at the 98.4% c

TOP Collaboration, MACRO Collaboration

The cosmic ray primary composition in the energy range between 10**15 and 10**16 eV, i.e., around the &#34;knee&#34; of the primary spectrum, has been studied through the combined measurements of the EAS-TOP air shower array (2005 m a.s.l., 10**5 m**2 collecting area) and the MACRO underground detector (963 m a.s.l., 3100 m w.e. of minimum rock overburden, 9

Suresh Chandra, S. A. Shinde

Yamamoto et al. (1987) reported the first detection of $c$-C$_3$H radical in {TMC-1} through its transition $2_{1 2} \to 1_{1 1}$ at 91.5 GHz. Mangum and Wootten (1990) detected $c$-C$_3$H through the transition $1_{1 0} \to 1_{1 1}$ at 14.8 GHz in 12 additional galactic objects. The column density of $c$-C$_3$H in the objects was estimated to be about one o

Hiroshi Nakajima, Kensuke Imanishi, Shin-ichiro Takagi, Katsuji Koyama

We report on the results of the Chandra observation on the central region of the Monoceros R2 cloud (Mon R2), a high-mass star-forming region (SFR). With a deep exposure of 100 ks, we detected 368 X-ray sources, 80% of which were identified with the NIR counterparts. We systematically analyzed the spectra and time variability of most of the X-ray emitting so

Frederic Cadet

In the framework of C*-algebraic deformation quantization we propose a notion of deformation groupoid which could apply to known examples e.g. Connes&#39; tangent groupoid of a manifold, its generalisation by Landsman and Ramazan, Rieffel&#39;s noncommutative torus, and even Landi&#39;s noncommutative 4-sphere. We construct such groupoid for a wide class of

Harumichi Nishimura, Tomoyuki Yamakami

Advice is supplementary information that enhances the computational power of an underlying computation. This paper focuses on advice that is given in the form of a pure quantum state and examines the influence of such advice on the behaviors of an underlying polynomial-time quantum computation with bounded-error probability.

Tarek Ibrahim, Pran Nath

The branching ratio of the lightest Higgs decay into $b\bar b$, $τ\barτ$ and $c\bar c$ is sensitive to supersymmetric effects. We include in this work the effects of CP phases on the Higgs decays. Specifically we compute the deviation of the CP phase dependent branching ratio from the standard model result. The analysis includes the full one loop corrections

Liviu Ornea, Misha Verbitsky

A locally conformally Kaehler (l.c.K.) manifold is a complex manifold admitting a Kaehler covering $\tilde M$, with each deck transformation acting by Kaehler homotheties. A compact l.c.K. manifold is Vaisman if it admits a holomorphic flow acting by non-trivial homotheties on $\tilde M$. We prove a structure theorem for compact Vaisman manifolds. Every comp

H. J. de Vega, J. A. Siebert

The non-relativistic self-gravitating gas in thermal equilibrium in the presence of a positive cosmological constant Lambda (dark energy) is investigated. The dark energy introduces a force pushing outward all particles with strength proportional to their distance to the center of mass.We consider the statistical mechanics of the self-gravitating gas of N pa

A. A. Malykh, Y. Nutku, M. B. Sheftel

We extend the Mason-Newman Lax pair for the elliptic complex Monge-Ampère equation so that this equation itself emerges as an algebraic consequence. We regard the function in the extended Lax equations as a complex potential. We identify the real and imaginary parts of the potential, which we call partner symmetries, with the translational and dilatational s

Wei-Min Sun, Hong-Shi Zong, Xiang-Song Chen, Fan Wang

The transverse axial vector and vector anomalies in four-dimensional U(1) gauge theories studied in [10] is reexamined by means of perturbative methods. The absence of transverse anomalies for both axial vector and vector current is verified. We also show that the Pauli-Villars regularization and dimensional regularization give the same result on the transve

Yair Goldin

The bispinor wave function finds its fundamental application in the study of electrons, neutrinos and protons as particles bound by their own potentials. Classical electromagnetism and the Dirac electron theory appear to be natural extensions of the physics that rules the electron itself. However, the charge density and the negative energy eigenvalues are tw

Jinfeng Liao, Pengfei Zhuang

A recently developed expansion method for analytically solving the ground states of strongly coupling Schrödinger equations by Friedberg, Lee and Zhao is extended to excited states and applied to the pedagogically important problems of power-law central forces. With the extended method, the Hydrogen atom problem is resolved and the low-lying states of Yukawa

Denes Molnar

The large and saturating differential elliptic flow v2(pT) observed in Au+Au reactions at RHIC so far could only be explained assuming an order of magnitude denser initial parton system than estimated from perturbative QCD. Hadronization via parton coalescence can resolve this ``opacity puzzle&#39;&#39; because it enhances hadron elliptic flow at large pT re

I. G. Bearden, NA44 Collaboration

For central PbPb collisions at a center of mass energy of 17.3 GeV/nucleon we have made the first two-dimensional measurement of the pp correlation function. These data extend the range of previous studies of HBT radii by a factor of two in transverse mass. They are consistent with a hydrodynamic interpretation and microscopic models that include hadronic re

V. I. Kuvshinov, A. V. Kuzmin

We consider the instanton approach to the problem of chaos assisted tunneling in the context of existing analytical and numerical results obtained in this field. We provide the estimation for the range of validity of this method and briefly discuss possible applications of chaos assisted tunneling for quantum computations.

V. I. Kuvshinov, A. V. Kuzmin, R. G. Shulyakovsky

For the system with one-dimensional spatially periodic potential we demonstrate that small periodic in time perturbation results in appearance of chaotic instanton solutions. We estimate parameter of local instability, width of stochastic layer and correlator for perturbed instanton solutions. Application of the instanton technique enables to calculate the a

Thomas W. Mueller, Jan-Christoph Schlage-Puchta

We derive an asymptotic expansion for the subgroup of arbitrary Fuchsian groups and some other classes of large groups. Moreover, the main conjecture for Random Walks on symmetric groups is established in full generality. Both problems require subtle estimates of character values and root number multiplicities for symmetric groups, which are also of independ

Silke Lekaus

We characterize those unipotent representations of the fundamental group $π_1(X,x)$ of a compact Kaehler manifold $X$, which correspond to a Higgs bundle whose underlying Higgs field is equal to zero. The characterization is parallel to the one that R. Hain gave of those unipotent representations of $π_1(X,x)$ that can be realized as the monodromy of a flat

J. -P. Serre

These informal notes are closely based on a series of eight lectures given by J.-P. Serre at the University of Oregon in October 1998. Professor Serre gave two talks per week for four weeks. The first talk each week was concerned with constructing embeddings of finite groups, especially $\PSL_2(p)$ and $\PGL_2(p)$, into Lie groups. The second talk each week