October 1999 arXiv papers — page 23

Yongzheng Zhang, Hongchen Fu, Allan I. Solomon

Intermediate states interpolating coherent states and Pegg-Barnett phase states are investigated using the ladder operator approach. These states reduce to coherent and Pegg-Barnett phase states in two different limits. Statistical and squeezing properties are studied in detail.

V. N. Gorbachev, A. I. Zhiliba

Consistent quantum formalism based on the localized basis of the Wannirer functions in Heisenberg and Schrodinger pictures to describe propagation of electromagnetic field in a three dimensional media including diffraction is presented. In the Schrodinger picture the Fokker-Planck equation for the Glauber-Sudarshan quasiprobability and corresponding Langevin

Pavel Bona

It is shown how nonlinear versions of quantum mechanics can be refolmulated in terms of a (linear) C*-algebraic theory. Then also their symmetries are described as automorphisms of the correspondong C*-algebra. The requirement of "conservation of transition probabilities" is discussed.

Pavel Bona

Proposals for nonlinear extenstions of quantum mechanics are discussed. Two different concepts of &#34;mixed state&#34; for any nonlinear version of quantum theory are introduced: (i) >genuine mixture< corresponds to operational &#34;mixing&#34; of different ensembles, and (ii) a mixture described by single density matrix without having a canonical operation

Samuel L. Braunstein, H. J. Kimble

A scheme to achieve dense quantum coding for the quadrature amplitudes of the electromagnetic field is presented. The protocol utilizes shared entanglement provided by nondegenerate parametric down conversion in the limit of large gain to attain high efficiency. For a constraint in the mean number of photons n associated with modulation in the signal channel

A. Mary Selvam, A. S. Ramachandra Murty, G. K. Manohar, S. S. Kandalgaonkar

Wilson&#39;s hypothesis of the global electric circuit with the thunderstorms as generators has not been proven up to now. The exact physical mechanism responsible for the generation of fair weather electric field is not clearly understood. Some of the recent remarkable observations showed evidence for the horizontal fields in the magnetosphere and ionospher

Alexander Morozovsky

New mathematical formulation of liquidity preference theory is suggested. On the base of comparison between suggested model and real prices paradoxical conclusion could be derived. The whole yield curve could be described only on the base of liquidity preference theory without any consideration of risk-neutral models.

P. Zinn-Justin

The study of a certain class of matrix integrals can be motivated by their interpretation as counting objects of knot theory such as alternating prime links, tangles or knots. The simplest such model is studied in detail and allows to rederive recent results of Sundberg and Thistlethwaite. The second non-trivial example turns out to be essentially the so-cal

Toshiki Shimbori, Tsunehiro Kobayashi

The paper deals with the one-dimensional parabolic potential barrier $V(x)={V_0-mγ^2 x^2/2}$, as a model of an unstable system in quantum mechanics. The time-independent Schrödinger equation for this model is set up as the eigenvalue problem in Gel&#39;fand triplet and its exact solutions are expressed by generalized eigenfunctions belonging to complex energ

Tomek Bartoszynski

A survey of recent results concerning cardinal invariants of measure and category. Submitted as a chapter of the upcoming Handbook of Set Theory.

Kirti Joshi, Eugene Z. Xia

Let X be a projective curve of genus 2 over an algebraically closed field of characteristic 2. The Frobenius map on X induces a rational map on the moduli scheme of rank-2 bundles. We show that up to isomorphism, there is only one (up to tensoring by an order two line bundle) semi-stable vector bundle of rank 2 (with determinant equal to a theta characterist

M. Mendes Lopes, R. Pardini

Let S be a minimal surface of general type with $p_g(S)=0$ and such that the bicanonical map $ϕ:S\to \pp^{K^2_S}$ is a morphism: then the degree of $ϕ$ is at most 4 and if it is equal to 4 then $K^2_S\le 6$. Here we prove that if $K^2_S=6$ and $°ϕ=4$ then S is a so-called {\em Burniat surface}. In addition we show that minimal surfaces with $p_g=0$, $K^2=6$

Adrian Baddeley, Martin Kerscher, Katja Schladitz, Bryan T. Scott

The interaction between points in a spatial point process can be measured by its empty space function F, its nearest-neighbour distance distribution function G, and by combinations such as the J-function $J = (1-G)/(1-F)$. The estimation of these functions is hampered by edge effects: the uncorrected, empirical distributions of distances observed in a bounde

Vladimir Turaev

We apply the idea of a topological quantum field theory (TQFT) to maps from manifolds into topological spaces. This leads to a notion of a (d+1)-dimensional homotopy quantum field theory (HQFT) which may be described as a TQFT for closed d-dimensional manifolds and (d+1)-dimensional cobordisms endowed with homotopy classes of maps into a given space. For a g

A. A. Slavnov

A manifestly Lorentz invariant effective action for Yang-Mills theory depending only on commuting fields is constructed. This action posesses a bosonic symmetry, which plays a role analogous to the BRST symmetry in the standard formalism.

C. M. Hull

One-dimensional sigma-models with N supersymmetries are considered. For conventional supersymmetries there must be N-1 complex structures satisfying a Clifford algebra and the constraints on the target space geometry can be formulated in terms of these. In the cases in which the complex structures are simultaneously integrable, a conventional extended supers

Tevian Dray, Corinne A. Manogue

We rewrite the standard 4-dimensional Dirac equation in terms of quaternionic 2-component spinors, leading to a formalism which treats both massive and massless particles on an equal footing. The resulting unified description has the correct particle spectrum to be a generation of leptons, with the correct number of spin/helicity states. Furthermore, precise

M. Bordemann, J. Hoppe, R. Suter

We show that the requirement of $S_3\times Spin(d)$ invariance for a ``asymptotically free&#39;&#39; SU(3)-Cartan subalgebra wave-function does {\em not} give a unique candidate for a SU(3)-invariant zero energy state of the d=9 supersymmetric matrix model - nor does it rule out the existence of such a state in the case d=3. For d=9 we explicitly construct v

G. B. Cleaver, A. E. Faraggi, D. V. Nanopoulos, J. W. Walker

Recently, we demonstrated the existence of heterotic--string solutions in which the observable sector effective field theory just below the string scale reduces to that of the MSSM, with the standard observable gauge group being just SU(3)_C x SU(2)_L x U(1)_Y and the SU(3)_C x SU(2)_L x U(1)_Y-charged spectrum of the observable sector consisting solely of t

S. Dawson, L. Reina

We investigate the inclusive production of a Higgs boson with a pair of heavy quarks (t-tbar b-bbar), in e^+e^- collisions at high energies, sqrt(s)=500 GeV and sqrt(s)=1 TeV. We consider both the Standard Model and the supersymmetric case. In both cases O(alpha_s) QCD corrections are included. The associated production of a Higgs boson with a t-tbar pair is

T. Hahn

Three programs are presented for automatically generating and calculating Feynman diagrams: the diagrams are generated with FeynArts, algebraically simplified with FormCalc, and finally evaluated numerically using the LoopTools package. The calculations are performed analytically as far as possible, with results given in a form well suited for numerical eval

I. A. Shovkovy, L. C. R. Wijewardhana

The superconductivity in cold dense QCD with three massless flavors is analyzed in the framework of the Schwinger-Dyson equation. The set of two coupled gap equations for the color antitriplet, flavor antitriplet (bar{3},bar{3}) and the color sextet, flavor sextet (6,6) order parameters is derived. It is shown that the antitriplet-antitriplet gives the domin

A. I. Davydychev

An arbitrary term of the epsilon-expansion of dimensionally regulated off-shell massless one-loop three-point Feynman diagram is expressed in terms of log-sine integrals related to the polylogarithms. Using magic connection between these diagrams and two-loop massive vacuum diagrams, the epsilon-expansion of the latter is also obtained, for arbitrary values

A. Hebecker

This brief review of hard diffraction is focussed on the theory of the diffractive structure function F_2^D. Some aspects of diffractive vector meson production and of diffractive processes in hadron-hadron collisions are also discussed.

Christoph Bobeth, Mikolaj Misiak, Joerg Urban

We calculate two-loop matching conditions for all the operators that are relevant to B -> X_s l^+ l^- decay in the Standard Model. In effect, we are able to remove the +_16% uncertainty in the decay spectrum, which was mainly due to the renormalization-scale dependence of the top-quark mass. We find 1.46 * 10^-6 for the branching ratio integrated in the doma

A. Capella

We describe particle production in the framework of an independent string model: the dual parton model. We show that an improved version of this model, containing a diquark breaking component, allows to describe the bulk of particle production and, in particular, baryon stopping and most of the observed enhancement of strange baryons. Only for very rare proc

F. Cardarelli, S. Simula

The exclusive semileptonic decay Lambda_b -> Lambda_c + l nu_l is investigated including both radiative and first-order power corrections in the inverse heavy-quark mass, while the Isgur-Wise function is calculated within a light-front constituent quark model. It turns out that the dependence on the model parameters can be effectively constrained using recen

K. Fialkowski, R. Wit

We analyse the cluster structure of the final multihadron states resulting from heavy ion collisions using the concept of Jaynes - Shannon entropy. Further evidence for an interesting differentiation of events is provided.

U. Sharan, M. Teper

We investigate the contribution that instantons make to the QCD chiral condensate for Nf= 0, 1 and 2 quark flavours. We use a simplified model: the instantons are a (weighted) gas, the fermionic integrations are restricted to the subspace spanned by the would-be zero-modes and only the dimensional and chiral features of the Dirac operator are retained. Previ

F. Myhrer

The observed scaling laws for large angle exclusive hadronic reactions are successfully accounted for by the short-distance QCD quark interchange processes. We focus on three hadronic reactions which shows evidence for a slight oscillatory deviation from the expected scaling behaviour. Possible explanations for these oscillations and connections to spin obse

W. Melnitchouk

I review some recent developments in the study of quark flavor distributions in the nucleon, including (i) valence quark distributions and the quark-hadron duality prediction for the x -> 1 d/u ratio (ii) sea quark asymmetries and electromagnetic form factors (iii) strange quarks in the nucleon.

Sinead M. Ryan, Aida X. El-Khadra, Andreas S. Kronfeld, Paul B. Mackenzie

We present an update of our calculation of the form factors and partial widths of semileptonic heavy-to-light meson decays, in the quenched approximation. Our complete data set has now been analysed and our results include chiral extrapolations and a study of the lattice spacing dependence.

S. Aoki, M. Fukugita, S. Hashimoto, K-I. Ishikawa

We present preliminary results of a new lattice computation of hadronic matrix elements of baryon number violating operators which appear in the low-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The contribution of irrelevant form factor which has caused an underestimate of the matrix elements in previous studies is subtracted in this calcula

W. Lee, D. Weingarten

We evaluate the continuum limit of the valence (quenched) approximation to the mass of the lightest scalar quarkonium state for a range of different quark masses and to the mixing energy between these states and the lightest scalar glueball. Our results support the interpretation of $f_0(1710)$ as composed mainly of the lightest scalar glueball.

A. Vaccarino, D. Weingarten

We evaluate the infinite volume, continuum limit of glueball masses in the valence (quenched) approximation to lattice QCD. For the lightest scalar and tensor states we obtain masses of $1648 \pm 58$ MeV and $2267 \pm 104$ MeV, respectively.

T. Thiemann

The present article summarizes the work of the papers \cite{1} dealing with the quantization of pure gravity and gravity coupled to a Maxwell field and a cosmological constant in presence of spherical symmetry. The class of models presented is intended as an interesting testing ground for the quantization of full 3+1 gravity. We are working in Ashtekar&#39;s

T. Thiemann

We present here the canonical treatment of spherically symmetric (quantum) gravity coupled to spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate momenta, whose geometrical interpreta

T. Thiemann

The preceding talks given at this conference have dealt mainly with general ideas for, main problems of and techniques for the task of quantizing gravity canonically. Since one of the major motivations to arrange for this meeting was that it should serve as a beginner&#39;s introduction to canonical quantum gravity, we regard it as important to demonstrate t

T. Thiemann

In order to test the canonical quantization programme for general relativity we introduce a reduced model for a real sector of complexified Ashtekar gravity which captures important properties of the full theory. While it does not correspond to a subset of Einstein&#39;s gravity it has the advantage that the programme of canonical quantization can be carried

T. Thiemann

There is a gap that has been left open since the formulation of general relativity in terms of Ashtekar&#39;s new variables namely the treatment of asymptotically flat field configurations that are general enough to be able to define the generators of the Lorentz subgroup of the asymptotical Poincaré group. While such a formulation already exists for the old

T. Thiemann

We extend here the canonical treatment of spherically symmetric (quantum) gravity to the most simple matter coupling, namely spherically symmetric Maxwell theory with or without a cosmological constant. The quantization is based on the reduced phase space which is coordinatized by the mass and the electric charge as well as their canonically conjugate moment

Z. Haba

Quantum mechanical interference of wave functions leads to some difficulties if a probability density is considered as a source of gravity. We show that an introduction of a quantum energy-momentum tensor as a source term in Einstein equations can be consistent with general relativity if the gravitational waves are quantized.

Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel

Downward translation of equality refers to cases where a collapse of some pair of complexity classes would induce a collapse of some other pair of complexity classes that (a priori) one expects are smaller. Recently, the first downward translation of equality was obtained that applied to the polynomial hierarchy-in particular, to bounded access to its levels

Edith Hemaspaandra, Lane A. Hemaspaandra, Harald Hempel

Hemaspaandra, Hempel, and Wechsung [cs.CC/9909020] initiated the field of query order, which studies the ways in which computational power is affected by the order in which information sources are accessed. The present paper studies, for the first time, query order as it applies to the levels of the polynomial hierarchy. We prove that the levels of the polyn

Ohan Baghdassarian, Bernd Tabbert, Gary A. Williams

A luminescence pulse has been observed from a laser-created bubble in liquid nitrogen and liquid argon at the first collapse point of the bubble. An unusual feature is that the width of the pulse is of order 100-1000 ns, much longer than the 2-8 ns pulses observed when the same experiment is carried out with a water sample.

Ethan H. Cannon, Feodor V. Kusmartsev, Kirill N. Alekseev, David K. Campbell

We study electron transport through a semiconductor superlattice subject to an electric field parallel to and a magnetic field perpendicular to the growth axis. Using a single miniband, semiclassical balance equation model with both elastic and inelastic scattering, we find that (1) the current-voltage characteristic becomes multistable in a large magnetic f

Marcel Reginatto, Florian Lengyel

It is shown that the diffusion equation and its adjoint (time reversed) equation can be derived with only a few assumptions, using an information-theoretic approach based on the principle of minimum Fisher information

G. B. Teitel&#39;baum, B. B=FCchner, H. de Gronckel

Using Cu NQR in Eu-doped La_{2- x}Sr_xCuO_4 we show the evidence of the pinned stripe phase for moderate doping at 1.3K. The pinned fraction increases by one order of magnitude near hole doping x=1/8. The NQR lineshape reveals three inequivalent Cu positions: i) sites in the charged stripe; ii) nonmagnetic sites outside the stripes; iii) sites with a magneti

H. Feldmann, R. Oppermann

We solve the fermionic version of the Ising spin glass for arbitrary filling μand temperature T taking into account replica symmetry breaking. Using a simple exact mapping from μto the anisotropy parameter D, we also obtain the solution of the S=1 Sherrington-Kirkpatrick model. An analytic expression for T=0 gives an improved critical value for the first-ord

L. Trappeniers, J. Vanacken, P. Wagner, G. Teniers

The normal state resistivity of high temperature superconductors can be probed in the region below Tc by suppressing the superconducting state in high magnetic fields. Here we present the normal state properties of YBa2Cu3Ox thin films in the underdoped regime and the normal state resistance of La2-xSrxCuO4 thin films under epitaxial strain, measured below T

N. Mousseau, D. A. Drabold

Many properties of alloyed chalcogenide glasses can be closely correlated with the average coordination of these compounds. This is the case, for example, of the ultrasonic constants, dilatometric softening temperature and the vibrational densities of states. What is striking, however, is that these properties are nevertheless almost independent of the compo

Alex Bunker, D. P. Landau

Using spin dynamics simulations we predict the splitting of the longitudinal spin wave peak in all antiferromagnets with single site anisotropy into two peaks separated by twice the energy gap at the Brillouin zone center. This phenomenon has yet to be observed experimentally but can be easily investigated through neutron scattering experiments on MnF$_2$ an

Adam Lipowski

Using Monte Carlo method we study a two-dimensional model with infinitely many absorbing states. Our estimation of the critical exponent beta=0.273(5) suggests that the model belongs to the (1+1) rather than (2+1) directed-percolation universality class. We also show that for a large class of absorbing states the dynamic Monte Carlo method leads to spurious

Zoltan Racz

It has been recently shown that precipitation bands characteristic of Liesegang patterns emerge from spinodal decomposition of reaction products in the wake of moving reaction fronts. This mechanism explains the geometric sequence of band positions x_n ~ Q(1+p)^n and, furthermore, it yields a spacing coefficient, p, that is in agreement with the experimental

I. S. Beloborodov, K. B. Efetov, A. I. Larkin

The magnetoresistance of a granular superconductor in a strong magnetic field is considered. It is assumed that this field destroys the superconducting gap in each grain, such that all interesting effects considered in the paper are due to superconducting fluctuations. The conductance of the system is assumed to be large, which allows us to neglect all local

Fumihiko Nakamura, Tatsuo Goko, Junya Hori, Yoshinori Uno

We have measured out-of-plane resistivity $ρ_c$ for La$_{2-x}$Sr$_{x}$CuO$_{4}$ under anisotropic pressure. c-axis compression, which decreases $ρ_c$, reduces $T_{\rm c}$ drastically, whereas c-axis extention, which increases $ρ_c$, enhances $T_{\rm c}$ from 38K at ambient pressure to 51.6K at 8GPa. We find that the variation of $T_{\rm c}$ scales as a funct

A. S. Mishchenko, N. V. Prokof&#39;ev, A. Sakamoto, B. V. Svistunov

A detailed study of the Frohlich polaron model is performed on the basis of diagrammatic quantum Monte Carlo method. The method is further developed both quantitatively (performance) and qualitatively (new estimators), and is enhanced by spectral analysis of the polaron Green function, within a novel approach. We present the best up to date results for the b

X. Qian, W. Hübner

Structure optimizations were performed for 1 and 2 monolayers (ML) of Fe on a 5 ML W(110) substrate employing the all-electron full-potential linearized augmented plane-wave (FP-LAPW) method. The magnetic moments were also obtained for the converged and optimized structures. We find significant contractions ($\sim$ 10 %) for both the Fe-W and the neighboring

Eugene H. Kim, G. Fath, J. Solyom, D. J. Scalapino

We consider various two-leg ladder models exhibiting gapped phases. All of these phases have short-ranged valence bond ground states, and they all exhibit string order. However, we show that short-ranged valence bond ground states divide into two topologically distinct classes, and as a consequence, there exist two topologically distinct types of string orde

Sriram Ramaswamy, John Toner, Jacques Prost

The stability of a flexible fluid membrane containing a distribution of mobile, active proteins (e.g. proton pumps) is shown to depend on the structure and functional asymmetry of the proteins. A stable active membrane is in a nonequilibrium steady state with height fluctuations whose statistical properties are governed by the protein activity. Disturbances

S. Leon, F. Combes, D. Friedli

NGC 5850 is a prototype of double-barred galaxy (Friedli et al. 1996) classified as SBb(sr) I-II (Higdon et al. 1998; Prieto et al. 1997). This kind of system is primordial to understand the physical mechanism responsible for feeding galaxy nuclei and boost the star formation rate. The CO(1-0) emission has been mapped in NGC 5850, i) in the very center, usin

C. Yuan, S. Leon

Recent NICMOS observations of the central regions of nearby barred galaxies, NGC5383, NGC1530 and NGC1667 by Regan, Sheth and Mulchaey (1999), all show, in the unsharp mask map, a pair of distinct trailing spirals which can be followed all the way to the center. This result is in apparent conflict with the density wave theory. In this report, we argue that t

I. Waddington, R. A. Windhorst, S. H. Cohen, R. B. Partridge

We present the discovery of a radio galaxy at a likely redshift of z = 4.424 in one of the flanking fields of the Hubble Deep Field. Radio observations with the VLA and MERLIN centered on the HDF yielded a complete sample of microjansky radio sources, of which about 20% have no optical counterpart to I < 25 mag. In this Letter, we address the possible nature

Maxim Lyutikov

We analyze mechanisms of the excitation of Alfvén wave in pulsar magnetospheres as a possible source of pulsar radio emission generation. We find that Cherenkov excitation of obliquely propagating Alfvén waves is inefficient, while excitation at the anomalous cyclotron resonance by the particles from the primary beam and from the tail of the bulk distributio

M. Landgraf, P. C. Frisch

We present a model of the interaction of interstellar dust grains with a stellar environment, that predicts the distribution of interstellar dust grains in the size range between $0.1 {\rm μm}$ and $1 {\rm μm}$ around a star for the whole stellar cycle. Comparisons of the model results with in-situ dust measurements by the Ulysses spacecraft in the Solar Sys

Roelof S. de Jong, Cedric Lacey

The local space density of galaxies as a function of their basic structural parameters -luminosity, surface brightness and scale size- is still poorly known. Our poor knowledge is the result of strong selection biases against low surface brightness and small scale size galaxies in any optically selected sample. We derive bivariate space density distributions

B. A. McLeod, E. E. Falco, C. S. Kochanek, J. Lehar

We use observations from the CASTLES survey of gravitational lenses to study extinction in 23 lens galaxies with $0 < z_l < 1$. The median differential extinction between lensed images is $ΔE(\bv) = 0.05$ mag, and the directly measured extinctions agree with the amount needed to explain the differences between the statistics of radio and (optical) quasar len

Ersin Gogus, Peter M. Woods, Chryssa Kouveliotou, Jan van Paradijs

We study the statistics of soft gamma repeater (SGR) bursts, using a data base of 187 events detected with BATSE and 837 events detected with RXTE PCA, all from SGR 1900+14 during its 1998-1999 active phase. We find that the fluence or energy distribution of bursts is consistent with a power law of index 1.66, over 4 orders of magnitude. This scale-free dist

D. A. Frail, S. R. Kulkarni, R. Sari, G. B. Taylor

We present multi-frequency radio observations from the afterglow of GRB 980519 beginning 7.2 hours after the gamma-ray burst and ending 63 days later. The fast decline in the optical and X-ray light curves for this burst has been interpreted either as afterglow emission originating from a collimated outflow -- a jet -- or the result of a blast wave propagati

Garret Cotter, Toby Haynes, Joanne C. Baker, Michael E. Jones

We have carried out a study to simulate distant clusters of galaxies in deep ground-based optical images. We find that when model galaxies are added to deep images obtained with the William Herschel Telescope, there is considerable scatter of the recovered galaxy colours away from the model values; this scatter is larger than that expected from photometric e

S. Chakravarti, K. Kar, A. Ray, S. Sarkar

A detailed model is constructed for the calculation of electron capture rates of some fp-shell nuclei for situations prevailing in pre-supernova and collapse phases of the evolution of the core of massive stars leading to supernova explosion. The model uses explicitly the Gamow-Teller strength function obtained through (n,p) reaction studies wherever availab

K. C. Freeman, M. Arnaboldi, M. Capaccioli, R. Ciardullo

We briefly describe the properties of the confirmed spectroscopic sample of intracluster planetary nebulae recently discovered in the Virgo cluster. We find 23 bonafide intracluster planetary nebulae and 8 high redshift (z ~ 3.1) Lyalpha emitters identified by their broad asymmetric emission line.

F. La Franca, C. Lissandrini, S. Cristiani, L. Miller

Spectra, position, magnitudes and colors are presented for 485 faint (B<20.5) emission line objects selected with the ultraviolet-excess (UVX) criterion on a area of 24.6 sq. deg in the South Galactic Pole. The objects were selected from the analysis of pixel-to-pixel stacking of COSMOS scans of UKST U, J and R plates. The candidates were observed with the M

G. C. Perola

From the spectral analysis of a broadband (0.1-200 keV) BeppoSAX observation of the Seyfert 1 galaxy IC 4329A, the main results obtained are: a) the amount of reflection, together with the intensity of the iron K line, indicate a geometry with a solid angle substantially less than 2pi; b) the power law is affected by a cut off with e-folding energy about 270

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

We report strong evidence for a ~304-day periodicity in the spin history of the accretion-powered pulsar GX1+4 that is most probably associated with the orbital period of the system. We have used data from the Burst and Transient Source Experiment on the Compton Gamma Ray Observatory to show a clear periodic modulation of the pulsar frequency from 1991 to da

F. D&#39;Antona, E. Oliva, A. Zeppieri

Methane brown dwarfs, i.e. objects similar to the low mass star Gliese 229B, are characterized by very unusual colours: J-K<~0 and I-J>~5. An analysis of the ESO public images, which cover an area of 37 sq. arcmin in the three filters, yields one clear methane dwarf candidate with J=20.2 and two fainter sources with J~=23. The resulting observed density of m

Jozef Klacka

The effect of nonradial component of solar wind is discussed from the qualitative point of view. It is shown that the direction of nonradial component is opposite in comparison with the direction used in papers dealing with orbital evolution of meteoroids.

Jozef Klacka

The problem of (non)random distribution of points on sphere and in space is investigated. The procedure for obtaining preferred direction (and plane) for points on the sphere (in the sky) and in the space is discussed. At present, directions of perihelia of the observed long-period comets cannot be considered to be distributed uniformly in the sky (contrary

Jozef Klacka

The problem of concentration of cometary perihelia on the sphere is discussed from the point of view of physics and astronomy. The important facts which may be crucial in understanding the observed concentration of cometary perihelia in the direction of solar apex are presented.

Jozef Klacka

The problem of (non)random distribution of points on the sphere is investigated. Published procedures for obtaining preferred direction and preferred plane for points on the sphere (in the sky) are discussed. It is shown that the published methods are incorrect, and, as a consequence, the results obtained by these methods cannot be considered to be significa

Jozef Klacka

Criterion for the membership of individual meteors to meteoroid streams presented by Valsecchi {\it et. al.} (1999) and Jopek {\it et. al.} (1999) is discussed. The authors characterize and use their criterion as a distance function. However, it is not a distance function. Some practical aspects are also discussed. Correct criterion is presented.

Jozef Klacka

Application of the theoretical results of the author are presented for the case of meteor streams of comet Encke. Theoretical determination of meteor orbit for comet Encke, as a parent body, is presented. Four significant theoretical meteor streams, corresponding to Tauds N, Tauds S, $β$ Tauds and $ξ$ Perds are found. The meteor stream membership criterion i

Jozef Klacka

Problem of meteor orbit determination for a given parent body is discussed. Some of the published methods for obtaining meteoroid&#39;s orbital elements at the moment of intersecting Earth&#39;s orbit on the basis of geometrical variation of parent body&#39;s orbital elements are discussed. The main result concerns the following two facts: i) in real situati

A. L. Coil, P. T. P. Ho

We report the results of a 5-field mosaic of the central 15pc of the Galaxy in the (1,1) and (2,2) lines of NH3. Two narrow filaments or streamers are seen running parallel to the Galactic plane. The southern streamer appears to carry gas directly toward the nuclear region from the 20 km/s cloud. The eastern streamer, which we will denote the molecular ridge

M. Kocifaj, J. Klacka

The importance of the Poynting-Robertson effect on the motion of interplanetary dust particles is discussed. Precise numerical calculations for real dust particle show that condition for the validity of the Poynting-Robertson effect is not fulfilled. The interaction of the (solar) electromagnetic radiation with really shaped dust particle is different from t

Jozef Klacka, Martin Gajdosik

Motion of a point mass in gravitational fields of the Sun and of the galactic disk is studied. Fundamental features of the motion are found by investigating the time-averaged differential equations for orbital evolution. Several types of possible orbits are mathematically exactly derived in a strictly analytical way. The relation $a^{3} ~ P^{2} = f (e_{0}, i

P. Marigo, L. Girardi, A. Weiss, M. A. T Groenewegen

The core mass-luminosity (Mc-L) relation of TP-AGB stars is a key ingredient in synthetic calculations of their evolution. Recently, Herwig et al. (1998) have presented full calculations of TP-AGB models with strong dredge-up occurring already during early thermal pulses. The resulting luminosity evolution differs appreciably from the simple linear Mc-L rela

Tomonori Totani, Chiaki Kobayashi

We have made a quantitative calculation for the systematic evolution of average extinction by interstellar dust in host galaxies of high-redshift Type Ia supernovae, by using a realistic model of photometric and chemical evolution of galaxies and supernova rate histories in various galaxy types. We find that average B band extinction <A_B> at z \sim 0.5 is t

J. Boguszynski, H. D. Dahmen, R. Kretschmer, L. Lukaszuk

A general form of multi-channel Bethe-Salpeter equation is considered. In contradistinction to the hitherto applied approaches, our coupled system of equations leads to the simultaneous solutions for all relativistic four-point Green functions (elastic and inelastic) appearing in a given theory. A set of relations which may be helpful in approximate treatmen

O. Rosas-Ortiz, B Mielnik, L. M. Nieto

The higher order susy partners of Schroedinger Hamiltonians can be explicitly constructed by iterating a nonlinear difference algorithm coinciding with the Backlund superposition principle used in soliton theory. As an example, it is applied in the construction of new higher order susy partners of the free particle potential, which can be used as a handy too

D. J. Fernandez C., O. Rosas-Ortiz

The derivation of a new family of magnetic fields inducing exactly solvable spin evolutions is presented. The conditions for which these fields generate the evolution loops (dynamical processes for which any spin state evolves cyclically) are studied. Their natural connection with geometric phases and the corresponding calculation is also elaborated.

J. Engel, J. L. Friar, A. C. Hayes

We examine the time-reversal-violating nuclear ``Schiff moment&#39;&#39; that induces electric dipole moments in atoms. After presenting a self-contained derivation of the form of the Schiff operator, we show that the distribution of Schiff strength, an important ingredient in the ground-state Schiff moment, is very different from the electric-dipole-strengt

Bogdan Mihaila, Jochen Heisenberg

We calculate the charge form factor and the longitudinal structure function for $^{16}$O and compare with the available experimental data, up to a momentum transfer of 4 fm$^{-1}$. The ground state correlations are generated using the coupled cluster [exp(S}] method, together with the realistic v-18 NN interaction and the Urbana IX three-nucleon interaction.

Gustavo Lopez

For a one-dimensional motion, a constant of motion for non autonomous an linear system (position and velocity) is given from the constant of motion associated to its autonomous system. This approach is used in the study of the harmonic oscillator with an additional time depending force.

J. M. Bang, A. I. Mazur, A. M. Shirokov, Yu. F. Smirnov

The relation between the R- and P-matrix approaches and the harmonic oscillator representation of the quantum scattering theory (J-matrix method) is discussed. We construct a discrete analogue of the P-matrix that is shown to be equivalent to the usual P-matrix in the quasiclassical limit. A definition of the natural channel radius is introduced. As a result

Alan Adolphson, Steven Sperber

In the 1960s, Dwork developed a p-adic cohomology theory of de Rham type for varieties over finite fields, based on a trace formula for the action of a Frobenius operator on certain spaces of p-adic analytic functions. One can consider a purely algebraic analogue of Dwork&#39;s theory for varieties over a field of characteristic zero and ask what is the conn

Yu. A. Sitenko

Effects of fermion-vacuum polarization by a singular configuration of an external static vector field are considered in (2 + 1)-dimensional spacetime. Expressions for the induced vacuum charge and magnetic flux are obtained.

A. Ilakovac

Low energy neutrinoless lepton flavor violating (LFV) processes are studied in an extension of the Standard Model (SM) by heavy SU(2)xU(1) singlet Dirac neutrinos. An upper bound procedure is elaborated for the evaluation of amplitudes. A comment on the extraction of heavy neutrino mixings from astrophysical observations is given. For processes not treated i

Valery Telnov

In this report on Photon Colliders the following technical aspects are considered: special requirements to an accelerator, new ideas on laser optics, laser cooling, and interaction region layout issues. In fact it is continuation of my first talk at this workshop where physics motivation, possible luminosities and backgrounds were discussed.

Valery Telnov

This report on Photon Colliders covers the following ``physics&#39;&#39; issues: physics motivation, possible luminosities, backgrounds, plans of works and international cooperation. More technical aspects such as accelerator issues, new ideas on laser optics, laser cooling, and interaction region layout are discussed in my second talk at this Workshop.