December 1999 arXiv papers — page 3

Eung Jin Chun, Sin Kyu Kang

We propose a radiative origin of the two mass splittings of three degenerate Majorana neutrinos. It can be achieved by extending the standard model to have the usual effective dimension 5 operators generating SO(3)-invariant tree-level masses, and a charged scalar singlet coupling with the leptons preserving the U(1) subgroup of SO(3). The mass splittings fo

D. P. Roy

Our concept of the basic constituents of matter has undergone two revolutionary changes -- from atoms to proton & neutron and then onto quarks & leptons. Indeed all these quarks and leptons have been seen by now along with the carriers of their interactions, the gauge bosons. But the story is not complete yet. A consistent theory of mass requires the presenc

S. Scopel, S. Cebrian, E. Garcia, D. Gonzalez

Prospects of WIMP searches using the annual modulation signature are discussed on statistical grounds, introducing sensitivity plots for the WIMP-nucleon scalar cross section.

Susumu Koretune

The modified Gottfried sum rule makes clear importance of the high energy region not only in the theoretical meaning but also in the numerical analysis. In this talk, it is shown that the soft pion theorem in the inclusive reaction at high energy can explain the magnitude about $0.02 \sim 0.04$ in the NMC deficit. The main contribution comes from the small $

Y. Kurihara, J. Fujimoto, Y. Shimizu, K. Kato

Inclusion of the QED higher order radiative corrections in the two-photon process, e+e- -> e+e- mu+mu-, is examined by means of the structure function and the parton shower. Results are compared with the exact $O(α)$ calculations and give a good agreement. These two methods should be universally applicable to any other non-annihilation processes like the sin

Zhang Chen

In this dissertation we develop a theoretical framework in the context of perturbative QuantumChromoDynamics (pQCD) for studying non-forward scattering processes. In particular, we investigate a non-forward unequal mass virtual Compton scattering amplitude by performing the general operator product expansion (OPE) and the formal renormalization group (RG) an

Vladimir M. Khatsymovsky

Dynamics of a Regge three-dimensional (3D) manifold in a continuous time is considered. The manifold is closed consisting of the two tetrahedrons with identified corresponding vertices. The action of the model is that obtained via limiting procedure from the general relativity (GR) action for the completely discrete 4D Regge calculus. It closely resembles th

Vladimir M. Khatsymovsky

The simplest (3+1)D Regge calculus model (with three-dimensional discrete space and continuous time) is considered which describes evolution of the simplest closed two-tetrahedron piecewise flat manifold in the continuous time. The measure in the path integral which describes canonical quantisation of the model in terms of area bivectors and connections as i

S. N. Artemenko

Conductivity mechanism in the regime of the intrinsic Josephson effect in layered superconductors with singlet d-wave pairing is studied theoretically. The cases of coherent and incoherent interlayer tunneling of electrons are considered. The theory with coherent tunneling describes main qualitative features of the effect observed in highly anisotropic high-

Udo Erdmann, Werner Ebeling, Lutz Schimansky-Geier, Frank Schweitzer

We study a model of Brownian particles which are pumped with energy by means of a non-linear friction function, for which different types are discussed. A suitable expression for a non-linear, velocity-dependent friction function is derived by considering an internal energy depot of the Brownian particles. In this case, the friction function describes the pu

Yong-Jihn Kim

It is shown that the Abrikosov's vortex solution or its corresponding two-particle pair potential is not the solution of the self-consistency equation in Gor'kov's formalism. Since the self-consistency equation leads to a superposition of different types of off-diagonal long-range order (ODLRO) instead of one type of ODLRO only, it may not handle

Nuria Calvet, Paola D'Alessio

Detailed radial/vertical structure modeling of observations of disks around Young Stellar Objects (YSOs) can provide information on the physical conditions and on the characteristics of the gas and dust in their interiors. We describe recent results of self-consistent modeling of spectral energy distributions, optical and infrared images, and millimeter flux

Richard B. Larson

The first bound star-forming systems in the universe are predicted to form at redshifts of about 30 and to have masses of the order of 10^6 M_sun. Although their sizes and masses are similar to those of present star-forming regions, their temperatures are expected to be much higher because cooling is provided only by trace amounts of molecular hydrogen. Seve

J. Goodman, B. Pindor

Late in the gaseous phase of a protostellar disk, centimeter-sized bodies probably settle into a thin ``dust layer'' at the midplane. A velocity difference between the dust layer and the gas gives rise to turbulence, which prevents further settling and direct gravitational instability of the layer. The associated drag on the surface of the layer caus

Alexander M. Ilyanok

The article describes new model of the Sun having a hollow core as introduced in [1]. The model helps to explain a number of experimental facts of kinetics, energetics, and Sun spectroscopy based on classic physics. The origin of the Sun's energy is not the thermonuclear process taking place in its core, but the coherent, anisotropic, gravitational compr

Mordecai-Mark Mac Low

I review what is known about the temperature of the plasma within stellar wind bubbles and superbubbles. Classical theory suggests that it should be hot, with characteristic temperatures of order a million degrees. This temperature should be set by the balance between heating by the internal termination shocks of the central stellar winds and supernovae, whi

B. J. Anthony-Twarog, B. A. Twarog

CCD photometry of the intermediate-age open cluster, IC 4651, on the uvbyHbeta system is presented and analyzed. By using a combination of the information from the color-magnitude diagram (CMD) and the color-color diagrams, a sample of 98 highly probable main sequence cluster members with high photometric accuracy is isolated. From this sample, adopting the

Alexander Knebe, Volker Mueller

Substructure in galaxy clusters can be quantified with the robust Delta statistics (Dressler and Shectman 1988) which uses velocity kinematics and sky projected positions. We test its sensitivity using dissipationless numerical simulations of cluster formation. As in recent observations, about 30 % of the simulated clusters show substructure, but the exact p

Spyros Basilakos, Manolis Plionis, Steve Maddox

We estimate the distribution of intrinsic shapes of the APM galaxy clusters from their corresponding distribution of projected shapes. We smooth the discrete galaxy distribution and define the cluster shape by fitting the best ellipse to the different isodensity contours. Using Monte-Carlo simulations we have studied the performance of our method in the pres

Rosa M. Gonzalez Delgado

RHII and starbursts are both powered by massive stars. They are the main contributors to the heating of the ISM via radiative and mechanical energy. Techniques to derive the stellar content and the evolutionary state of RHIIs and starbursts from their ultraviolet and optical integrated light are reviewed. A prototypical RHII (NGC 604) and nuclear starburst (

Toma Tomov, Ulisse Munari, Paola Marrese

The spectral signature of collimated bipolar jets have been discovered on high resolution spectra of Hen 3-1341 during the 1999 outburst, the first ever recorded for this symbiotic star. The jets show up as emission components at DeltaRV = 820 km/sec on both sides of the main emission lines. They were not present in quiescence. As a general rule for the jets

Tadashi Nakajima, Takashi Tsuji, Toshinori Maihara, Fumihide Iwamuro

Using the Subaru Telescope, we have obtained multiple near-infrared spectra of the cool brown dwarf, SDSS 1624+00, in search of spectral variability in an 80 minute time span. We have found the suspected variability of water vapor absorption throughout the observations, which requires confirmation by a longer time baseline. After coadding the spectra, we hav

Yoshiaki Sofue

Using the all-sky ROSAT soft X-ray and 408-MHz radio continuum data, we show that the North Polar Spur and its western and southern counter-spurs draw a giant dumbbell-shape necked at the galactic plane. We interpret these features as due to a shock front originating from a starburst 15 million years ago with a total energy of the order of $\sim 10^{56}$ erg

Tanusri Ghosh, Somenath Chakrabarty

The effect of strong quantizing magnetic field on the nucleation of quark matter droplets and on the chemical evolution of nascent quark phase at the core of a neutron star are investigated. The surface energy of quark phase diverges logarithmically. As a consequence there can not be a first order transition to quark phase. However, a metal-insulator type of

C. Ikuta, N. Arimoto

The origin of abundance spreads observed in omega Centauri is studied in the context of the self-enrichment scenario. Five chemical evolution models are constructed and are compared with empirical metallicity distribution of $ω$ Cen. After a series of simulations, it is found that neither of closed-box, outflow, nor infall models can reproduce the empirical

D. L. Jones, A. E. Wehrle, D. L. Meier, B. G. Piner

The structure of AGN accretion disks on sub-parsec scales can be probed through free-free absorption of synchrotron emission from the base of symmetric radio jets. We present new VLBA observations of the nearby FR-I radio galaxy NGC 4261 at 22 and 43 GHz, and combine these with previous VLBA observations at 1.6 and 8.4 GHz to map absorption caused by an inne

M. Carena, D. Garcia, U. Nierste, C. E. M. Wagner

In the framework of a 2HDM effective lagrangian for the MSSM, we analyse important phenomenological aspects associated with quantum soft SUSY-breaking effects that modify the relation between the bottom mass and the bottom Yukawa coupling. We derive a resummation of the dominant supersymmetric corrections for large values of \tb to all orders in perturbation

D0 Collaboration, B. Abbott

We report on a measurement of sigma(p-pbar to W+X) times B(W to tau+nu) in p-pbar collisions at sqrt(s) = 1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity of 18 pb^-1 of data collected with the D0 detector during 1994-1995. We find that sigma(p-pbar to W+X) times B(W to tau+nu) = 2.22 +- 0.09 (stat) +- 0.10 (syst) +- 0.1

M. Cristina Marchetti, A. Alan Middleton, Thomas Prellberg

We have investigated the mean field dynamics of an overdamped viscoelastic medium driven through quenched disorder. The model introduced incorporates coexistence of pinned and sliding degrees of freedom and can exhibit continuous elastic depinning or first order hysteretic depinning. Numerical simulations indicate mean field instabilities that correspond to

Carlo Angelantonj, Adi Armoni

We discuss gauge theories on D3 branes embedded in special non-tachyonic orientifolds of the 0B string theory. In general, they correspond to non-supersymmetric SU(N) gauge theories with scalars in the adjoint representation and spinors in the (anti-)symmetric representation. We study these theories via the AdS/CFT correspondence and present evidence of thei

Tamiaki Yoneya

We argue that orientable open string theory without GSO projection has N=2 space-time supersymmetry in a spontaneously broken phase. The arguments are presented both in Neveu-Schwarz-Ramond and Green-Schwarz formulations. The formal but explicit supersymmetry transformation law for string field is given in the framework of Witten's open string field theo

A. Gomez Nicola, J. R. Pelaez

By means of the Inverse Amplitude Method we unitarize the elastic pion-nucleon scattering amplitudes obtained from Heavy Baryon Chiral Perturbation Theory to O(q^3). Within this approach we can enlarge their applicability range and generate the Delta(1232) resonance. We can find a reasonable description of the pion nucleon phase shifts with (q^2) parameters

Kunihito Uzawa, Yoshiyuki Morisawa, Shinji Mukohyama

We investigate excitation of Kaluza-Klein modes due to the parametric resonance caused by oscillation of radius of compactification. We consider a gravitational perturbation around a D-dimensional spacetime, which we compactify on a (D-4)-sphere to obtain a 4-dimensional theory. The perturbation includes the so-called Kaluza-Klein modes, which are massive in

Nazeem Mustapha, George F R Ellis, Henk van Elst, Mattias Marklund

We show that there are no new consistent cosmological perfect fluid solutions when in an open neighbourhood ${\cal U}$ of an event the fluid kinematical variables and the electric and magnetic Weyl curvature are all assumed rotationally symmetric about a common spatial axis, specialising the Weyl curvature tensor to algebraic Petrov type D. The consistent so

Fumihiko Sugino

In this paper we consider Witten's bosonic open string field theory in the presence of a constant background of the second-rank antisymmetric tensor field $B_{ij}$. We extend the operator formulation of Gross and Jevicki in this situation and construct the overlap vertices explicitly. As a result we find a noncommutative structure of the Moyal type only

Tsutomu Sakai, Kiyotaka Shimizu, Koichi Yazaki

The quark cluster model studies concerning the H-dibaryon are reviewed. The covered topics are the H-dibaryon itself, the interaction between a nucleon and an H-dibaryon, and the one between two H-dibaryons. A related study on the H-dibaryon in nuclear matter is also reviewed and its implication to double hypernuclei is discussed.

Chul-Ho Lee, Kazuyoshi Yamada, Yasuo Endoh, Gen Shirane

The energy spectrum of incommensurate spin fluctuations in superconducting Sr-doped La2CuO4 has been studied by inelastic neutron scattering experiments. An energy gap in the spin excitation spectrum is observed in the superconducting state of optimally doped (x=0.15) and slightly overdoped (x=0.18) samples. At temperatures well below Tc, the incommensurate

K. Sasaki, M. Hotta

An attempt is made to construct composable composite entropy with different $q$ indices of subsystems and address the H-theorem problem of the composite system. Though the H-theorem does not hold in general situations, it is shown that some composite entropies do not decrease in time in near-equilibrium states and factorized states with negligibly weak inter

Hangmo Yi

We study mesoscopic resonant tunneling as well as multichannel Kondo problems by mapping them to a first-quantized quantum mechanical model of a particle moving in a multi-dimensional periodic potential with Ohmic dissipation. From a renormalization group analysis, we obtain phase diagrams of the quantum Brownian motion model with various lattice symmetries.

W. B. Lin, X. H. Meng, X. M. Zhang

We study the possibilities of parametric amplification of the gravitational perturbation during reheating in single-field inflation models. Our result shows that there is no additional growth of the super-horizon modes beyond the usual predictions.

Harold Blas

We discuss some algebraic aspects of the integrable vector non-linear Schrödinger hierarchies (GNLS$_{r}$). These are hierarchies of zero-curvature equations constructed from affine Kac-Moody algebras $\hat{sl}_{r+1}$. Using the dressing transformation method and the tau-function formalism, we construct the N-soliton solutions of the GNLS$_{r}$ systems. The

Supriyo Bandyopadhyay

Intriguing dichotomies in quantum measurement theory involving the role of the obersever, objective reality, collapse of wavefunctions and actualization of a measurement outcome are cast into a patholigical gedanken experiment involving a single electron in a double quantum dot system coupled via a weak link.

A. Lavagno, P. Narayana Swamy

We show that a natural realization of the thermostatistics of q-bosons can be built on the formalism of q-calculus and that the entire structure of thermodynamics is preserved if we use an appropriate Jackson derivative in place of the ordinary thermodynamics derivative. This framework allows us to obtain a generalized q-boson entropy which depends on the q-

Hidekatsu Nemura, Yasuyuki Suzuki, Yoshikazu Fujiwara, Choki Nakamoto

We first determine the Lambda-N S-wave phase shifts so as to reproduce the experimental Lambda separation energies of A=3, 4 Lambda-hypernuclei, and then construct three phase-equivalent Lambda-N potentials with different central repulsion. By the stochastic variational method with correlated Gaussian basis we perform an extensive calculation of ab initio ty

A. Lavagno, P. Quarati

Nonextensive and quantum uncertainty effects (related to the quasiparticles composing the stellar core) have strong influence on the nuclear rates and, of course, affect solar neutrino fluxes. Both effects do coexist and are due to the frequent collisions among the ions. The weakly nonextensive nature of the solar core is confirmed. The range of predictions

Sudhir R. Jain

We present a systematic theory of dissipation in finite Fermi systems like nuclei and metallic clusters. This theory is based on the application of semiclassical methods and random matrix theory to linear response of many-body systems. The theory is developed in the approximation wherein the many-body system can be treated as a single particle in an effectiv

J. Bricmont, A. Kupiainen, R. Lefevere

We consider the Navier-Stokes equation on a two dimensional torus with a random force, white noise in time and analytic in space, for arbitrary Reynolds number $R$. We prove probabilistic estimates for the long time behaviour of the solutions that imply bounds for the dissipation scale and energy spectrum as $R\to\infty$.

Lowell Abrams, Charles Weibel

Let C be a coalgebra over a field k and A its dual algebra. The category of C-comodules is equivalent to a category of A-modules. We use this to interpret the cotensor product M \square N of two comodules in terms of the appropriate Hochschild cohomology of the A-bimodule M \otimes N, when A is finite-dimensional, profinite, graded or differential-graded. Th

R. M. Kashaev, O. Tirkkonen

The volume conjecture, formulated recently by H. Murakami and J. Murakami, is proved for the case of torus knots.

Goro Hatayama, Kazuhiro Hikami, Rei Inoue, Atsuo Kuniba

A soliton cellular automaton associated with crystals of symmetric tensor representations of the quantum affine algebra U'_q(A^{(1)}_M) is introduced. It is a crystal theoretic formulation of the generalized box-ball system in which capacities of boxes and carriers are arbitrary and inhomogeneous. Scattering matrices of two solitons coincide with the com

Chuan-Tsung Chan

Exact solutions to the Dirac-Born-Infeld equation, which describes scatterings of localized wave packets in the presence of constant background fields, are derived in this paper.

Cristian Martinez, Claudio Teitelboim, Jorge Zanelli

The generalization of the black hole in three-dimensional spacetime to include an electric charge Q in addition to the mass M and the angular momentum J is given. The field equations are first solved explicitly when Q is small and the general form of the field at large distances is established. The total ``hairs'' M, J and Q are exhibited as boundary

Yusuke Kimura, Yoshihisa Kitazawa

We consider IIB matrix model with D1-D5-brane backgrounds. Using the fact that noncommutative gauge theory on the D-branes can be obtained as twisted reduced model in IIB matrix model, we study two-dimensional gauge theory on D1-branes and D5-branes. Especially the spectrum of the zero modes in the off-diagonal parts is examined. We also consider the descrip

C. P. Constantinidis, F. P. Devecchi, D. F. Marchioro

The zero-hamiltonian problem, present in reparametrization invariant systems, is solved for the 2-D induced gravity model. Working with methods developed by Henneaux et al. we find systematically the reduced phase-space physics, generated by an {\it effective} hamiltonian obtained after complete gauge fixing.

Kazuo Fujikawa, Hiroaki Terashima

In the absence of Gribov complications, the modified gauge fixing in gauge theory $ \int{\cal D}A_μ\{\exp[-S_{YM}(A_μ)-\int f(A_μ)dx] /\int{\cal D}g\exp[-\int f(A_μ^{g})dx]\}$ for example, $f(A_μ)=(1/2)(A_μ)^{2}$, is identical to the conventional Faddeev-Popov formula $\int{\cal D}A_μ\{δ(D^μ\frac{δf(A_ν)}{δA_μ})/\int {\cal D}gδ(D^μ\frac{δf(A_ν^{g})} {δA_μ^{g

V. Fridkin, Yu. Stroganov, D. Zagier

We find an analytic solution of the Bethe Ansatz equations (BAE) for the special case of a finite XXZ spin chain with free boundary conditions and with a complex surface field which provides for $U_q(sl(2))$ symmetry of the Hamiltonian. More precisely, we find one nontrivial solution, corresponding to the ground state of the system with anisotropy parameter

Juan Garcia-Bellido, Dmitri Grigoriev

It has recently been proposed that the production of long wavelength Higgs and gauge configurations via parametric resonance at the end of inflation may give rise to the required baryon asymmetry at the electroweak scale. We show that the stability of the inflaton oscillations, long after the production of Higgs modes, keeps driving the sphaleron transitions

Jiri Chyla, Marek Tasevsky

Interactions of virtual photons are analyzed in terms of photon structure. It is argued that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. This claim is illustrated on leading order expressions for $F_2^γ(x,P^2,Q^2)$ and effective parton distribution function $D_{\m

Vincenzo Cirigliano, Eugene Golowich

The one-loop corrections to K->pi and K->2pi matrix elements of the electroweak penguin operator are calculated. General next-to-leading order relations between the K->pi and K->2pi amplitudes are obtained. The fractional shift Delta_2 = 0.27 +- 0.27 is found for the O(p^2) corrections to a recent chiral determination of <(pi pi)_{I=2}|Q_{7,8}|K^0>. We expla

Bernd A. Berg, Harald Markum, Rainer Pullirsch, Tilo Wettig

We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) gauge theory and in full QCD as well as in quenched U(1) theory on various lattice sizes. As a measure of the fluctuation properties of the eigenvalues, we study the nearest-neighbor spacing distribution, $P(s)$. We further study lattice QCD at nonzero chemical potential, $μ$, by c

L. Gladilin

The world average values for the probabilities that a charm quark fragments into D^*+ and Ds^+ have been calculated to be f(c->D^*+)=0.235+/-0.007(+/-0.007) and f(c->Ds^+)=0.101+/-0.009(+/-0.025), respectively. The average values for D^0, D^+ and Lambda_c^+ have been also calculated.

G. A. Alekseev

The approach, referred to as &#34;monodromy transform&#34;, provides some general base for solution of all known integrable space - time symmetry reductions of Einstein equations for the case of pure vacuum gravitational fields, in the presence of gravitationally interacting massless fields, as well as for some string theory induced gravity models. In this c

T. T. Nguyen, A. Yu. Grosberg, B. I. Shklovskii

Screening of a strongly charged macroion by oppositely charged colloidal particles, micelles, or short polyelectrolytes is considered. Due to strong lateral repulsion such multivalent counterions form a strongly correlated liquid at the surface of the macroion. This liquid provides correlation induced attraction of multivalent counterions to the macroion sur

Mona Berciu, Sajeev John

We demonstrate that the Configuration Interaction (CI) Approximation recaptures essential features of the exact (Bethe Ansatz) solution to the 1D Hubbard model. As such, it provides valuable route for describing effects which go beyond mean-field theory for strongly correlated electron systems in higher dimensions. The CI method systematically describes fluc

Z. Pluhar, H. A. Weidenmueller

We prove ergodicity of unitary random-matrix theories by showing that the autocorrelation function with respect to energy or magnetic field strength of any observable vanishes asymptotically. We do so using Efetov&#39;s supersymmetry method, a polar decomposition of the saddle-point manifold, and an asymptotic evaluation of the boundary terms generated in th

J. C. Flores, V. Bellani, F. Dominguez-Adame

We introduce an elementary model for the electrostatic self-consistent potential in a two-dimensional electron gas. By considering the perpendicular degree of freedom arising from the electron tunneling out of the system plane, we predict a threshold carrier density above which this effect is relevant. The predicted value agrees remarkably well with the onse

Michael Korotin, Takeo Fujiwara, Vladimir Anisimov

The electronic structure of La 7/8 Sr 1/8 MnO 3 was studied by using the rotation-invariant LSDA (Local Spin Density Approximation)+U formalism. We found the specific kind of charge and orbital order for ferromagnetic insulating solution in 2a*2b*4c supercell, where a, b, and c denote cubic perovskite axes. The holes are distributed over 3-line stripes in ev

A. S. Mel&#39;nikov

Theory of scanning tunneling spectroscopy of low energy quasiparticle (QP) states in vortex lattices of d-wave superconductors is developed taking account of the effects caused by an extremely large extension of QP wavefunctions in the nodal directions and the band structure in the QP spectrum. The oscillatory structures in STM spectra, which correspond to v

J. H. Jung, H. J. Lee, T. W. Noh, E. J. Choi

We investigated the temperature ($T=$ 15 $\sim $ 290 K) and the magnetic field ($H=$ 0 $\sim $ 17 T) dependent optical conductivity spectra of a charge/orbital ordered manganite, Nd$_{1/2}$Sr$_{1/2}$MnO$_3$. With variation of $T$ and $H$, large spectral weight changes were observed up to 4.0 eV. These spectral weight changes could be explained using the pola

M. Hotta

This paper has been withdrawn by the author and the content is merged into a new paper: H-Theorem and Generalized Entropy Composition with Different q Indices: cond-mat/9912454.

Tohru Koma

A two-dimensional quantum Hall system is studied for a wide class of potentials including single-body random potentials and repulsive electron-electron interactions. We assume that there exists a non-zero excitation gap above the ground state(s), and then the conductance is derived from the linear perturbation theory with a sufficiently weak electric field.

Tohru Koma

A two-dimensional quantum Hall system without disorder for a wide class of interactions including any two-body interaction with finite range is studied by using the Lieb-Schultz-Mattis method [{\it Ann. Phys. (N.Y.)} {\bf 16}: 407 (1961)]. The model is defined on an infinitely long strip with a fixed large width, and the Hilbert space is restricted to the lo

F. Nicastro

We present a model which relates the width of the Broad Emission Lines of AGN to the Keplerian velocity of an accretion disk at a critical distance from the central black hole. This critical distance falls in a region bounded on the inward side by the transition radius between the radiation pressure and the gas pressure dominated region of the accretion disk

E. L. Wright, E. D. Reese

We compare data from the Diffuse InfraRed Background Experiment (DIRBE) on the Cosmic Background Explorer (COBE) satellite to the the Wainscoat et al. (1992) model of the infrared sky. The model is first compared with broadband K (2.2 microns) star counts. Its success at K gives credence to its physical approach which is extrapolated to the L band (3.5 micro

Dong Lai

It is no longer necessary to `sell&#39; the idea of pulsar kicks, the notion that neutron stars receive a large velocity (a few hundred to a thousand km s$^{-1}$) at birth. However, the origin of the kicks remains mysterious. We review the physics of different kick mechanisms, including hydrodynamically driven, neutrino and magnetically driven kicks.

Jose-Luis Gomez, Alan P. Marscher

We present the first space VLBI observations of 3C~371, carried out at a frequency of 4.8 GHz. The combination of the high resolution provided by the orbiting antenna Highly Advanced Laboratory for Communications and Astronomy (HALCA) and the high sensitivity of the VLBA allows imaging of the jet of 3C~371 with an angular resolution of approximately 0.26 mas

R. W. Lessard, I. H. Bond, S. M. Bradbury, J. H. Buckley

We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory&#39;s 10 m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 November and 1997 March. During this period the Whipple 10 m telescope was operated at its lowest energy threshold to date. Spectral

Joao Braga, Marildo G. Pereira, Francisco J. Jablonski

In this paper we report strong evidence for a ~304-day periodicity in the spin history of the accretion-powered pulsar GX 1+4 that is very likely to be a signature of the orbital period of the system. Using BATSE public-domain data, we show a highly-significant periodic modulation of the pulsar frequency from 1991 to date which is in excellent agreement with

Kiran Jain, S. C. Tripathy, A. Bhatnagar, B. Kumar

We have obtained empirical relations between the p-mode frequency shift and the change in solar activity indices. The empirical relations are determined on the basis of frequencies obtained from BBSO and GONG stations during solar cycle 22. These relations are applied to estimate the change in mean frequency for the cycle 21 and 23. A remarkable agreement be

J. Erdmenger, M. Perez-Victoria

We show that next-to-extremal correlators of chiral primary operators in N=4 SYM theory do not receive quantum corrections to first order in perturbation theory. Furthermore we consider next-to-extremal correlators within AdS supergravity. Here the exchange diagrams contributing to these correlators yield results of the same free-field form as obtained withi

Ken-Ichi Aoki, Atsushi Horikoshi, Etsuko Nakamura

We discuss the propagation of wave packets through interacting environments. Such environments generally modify the dispersion relation or shape of the wave function. To study such effects in detail, we define the distribution function P_{X}(T), which describes the arrival time T of a packet at a detector located at point X. We calculate P_{X}(T) for wave pa

V. B. Belyaev, Yu. Z. Ionikh, M. B. Miller, A. K. Motovilov

Experiments aimed at testing some hypothesis about the nature of Single Bubble Sonoluminescence are discussed. A possibility to search for micro-traces of thermonuclear neutrons is analyzed, with the aid of original low-background neutron counter operating under conditions of the deep shielding from Cosmic and other sources of background. Besides, some signa

Rob Clifton

We give two simple Kochen-Specker arguments for complementary between the position and momentum components of spinless particles, arguments that are identical in structure to those given by Peres and Mermin for spin-1/2 particles.

H. D. Zeh

Rohrlich&#39;s recent claim that the equation of motion for a point charge be symmetric under time reversal is shown to be the result of an unusual definition. The equation of motion for a charged sphere of finite size, which in contrast is claimed to be asymmetric because of the finite propagation time of its (retarded) self-forces, is shown to possess the

Hart Smith, Christopher D. Sogge

The authors show that bilinear estimates for null forms hold for Dirichlet-wave equations outside of convex obstacle. This generalizes results for the Euclidean case of Klainerman and Machedon, and of Sogge for the variable coefficient boundaryless case. The estimates are used to prove a local existence theorem for semilinear wave equations satisfying the nu

V. Georgiev, Hans Lindblad, Christopher D. Sogge

We prove certain weighted Strichartz estimates and use these to prove a sharp theorem for global existence of small amplitude solutions of $\square u= |u|^p$, thus verifying the so-called &#34;Strauss conjecture&#34;.

Daniel Oberlin, Hart Smith, Christopher D. Sogge

We establish $L^p$ Sobolev mapping properties for averages over certain curves in $\R^3$, which improve upon the estimates obtained by $L^2-L^\infty$ interpolation.

Hart Smith, Christopher D. Sogge

The authors prove global Strichartz estimates for compact perturbations of the wave operator in odd dimensions when a non-trapping assumption is satisfied.

Christopher D. Sogge

We obtain estimates for maximal functions that arise when one studies Nikodym-type sets. We also formulate a curvature condition that allows favorable estimates for these maximal functions.

William Minicozzi, Christopher D. Sogge

We expand on counterxamples of Bourgain showing how Nikodym maximal estimates and oscillatory integral estimates can break down in the non-Euclidean case. Our examples show the role that the non-existence of totally geodesic submanifolds can play in these problems.

Marcus Keel, Hart Smith, Christopher D. Sogge

We prove global existence for semilinear hyperbolic equations that satisfy the null condition of Christodoulou and Klainerman in the exterior of convex domains. We use a combination of the conformal method of Christodoulou and the direct method of Klainerman.

Yakov Varshavsky

This paper has been withdrawn by the author, due an error in the proof of Proposion 2.13.

M. B. Hott, J. L. Tomazelli

In this work we derive the Lorentz-PCT-violating effective action for a fermion in a constant and uniform electromagnetic field using the Fock-Schwinger proper time method and extract the exact value of the coefficient of the nonperturbatively induced Chern-Simons term.

Mu-Lin Yan

The Davey-Stewartson 1(DS1) system[9] is an integrable model in two dimensions. A quantum DS1 system with 2 colour-components in two dimensions has been formulated. This two-dimensional problem has been reduced to two one-dimensional many-body problems with 2 colour-components. The solutions of the two-dimensional problem under consideration has been constru

M. Boz, E. Iltan

We analyse the CP asymmetry for B_{s} -->γγin the two Higgs doublet model with tree level flavor changing currents (model III) and three Higgs doublet model with O_2 symmetry in the Higgs sector, including O_{7} type long distance effects. Further, we study the dependencies of the branching ratio Br(B_{s} --> γγ)$ and the ratio of CP-even and CP-odd amplitud

Chao Tang

The protein folding problem has attracted an increasing attention from physicists. The problem has a flavor of statistical mechanics, but possesses the most common feature of most biological problems -- the profound effects of evolution. I will give an introduction to the problem, and then focus on some recent work concerning the so-called ``designability pr

E. B. Gregory, S. Guo, H. Kroger, Xiang-Qian Luo

At sufficiently high temperature and density, quantum chromodynamics (QCD) is expected to undergo a phase transition from the confined phase to the quark-gluon plasma phase. In the Lagrangian lattice formulation the Monte Carlo method works well for QCD at finite temperature, however, it breaks down at finite chemical potential. We develop a Hamiltonian appr

R. G. Vishwakarma

Observations of supernovae of type Ia require dark energy (some unknown exotic \emph{`matter&#39;} of negative pressure) to explain their unexpected faintness. Whereas the simplest and most favoured candidate of dark energy, the Einsteinian cosmological constant, is about 120 orders of magnitude smaller than the theoretically predicted value. Motivated by th

Yu. G. Prokhorov, V. V. Shokurov

The aim of this paper is to clarify and generalize techniques of works alg-geom/9711024 (see also math.AG/9810097 and math.AG/9901004). Roughly speaking, we prove that for local Fano contractions the existence of complements can be reduced to the existence of complements for lower dimensional projective Fano varieties.

Katsuyuki Nakanishi, Yoshiko Oi Nakamura

The effect of the domain wall (DW) on the conductance in a ballistic ferromagnetic nanowire (FMNW) is revisited by exploiting a specific perturbation theory which is effective for a thin DW; the thinness is often the case in currently interested conductance measurements on FMNWs. Including the Hund coupling between carrier spins and local spins in a DW, the