October 1998 arXiv papers — page 19

Y. Ueda, M. Ishida, H. Inoue, T. Dotani

We observed the newly discovered Galactic jet source XTE J0421+560 (= CI Cam) with ASCA from 1998 April 3.3 to April 4.1 (UT), three days after the beginning of the outburst. The X-ray intensity in the 1-10 keV band gradually decreased with an e-folding time of about 30 hours; the decline was accompanied by spectral softening. Two flare-like intensity enhanc

Piotr T. Chruściel

We show that static electro-vacuum black hole space-times containing an asymptotically flat spacelike hypersurface with compact interior and with both degenerate and non-degenerate components of the event horizon do not exist, under the supplementary hypothesis that all degenerate components of the event horizon have charges of the same sign. This extends pr

Olivier Devillers

We use here the results on the influence graph by Boissonnat et al. to adapt them for particular cases where additional information is available. In some cases, it is possible to improve the expected randomized complexity of algorithms from O(n log n) to O(n log star n). This technique applies in the following applications: triangulation of a simple polygon,

J. Amorós, F. Bogomolov, L. Katzarkov, T. Pantev

In this paper we give an explicit construction of a symplectic Lefschetz fibration whose total space is a smooth compact four dimensional manifold with a prescribed fundamental group. We also study the numerical properties of the sections in symplectic Lefschetz fibrations and their relation to the structure of the monodromy group.

D. Grecu, A. S. Cârstea, Anca Visinescu

Self-localized modes in a quantum vibronic system, with long range interaction of Kac-Baker type and interacting nonlinearly with an acoustical phonon bath, is studied. One works in the coherent state approximation. Following a procedure of Sarker and Krumhansl, the problem is reduced to a nearest neighbours one. In the continuum limit the localized state sa

Guihua Zeng

The security of the previous quantum key distribution protocols, which is guaranteed by the nature of physics law, is based on the legitimate users. However, the impersonation of Alice or Bob by eavesdropper, in practice. will be existed in a large probability. In this paper an improvement scheme for the security quantum key is proposed.

C. Cabrillo, J. L. Roldan, P. Garcia-Fernandez

Quantum noise in a model of singly resonant frequency doubling including phase mismatch and driving in the harmonic mode is analyzed. The general formulae about the fixed points and their stability as well as the squeezing spectra calculated linearizing around such points are given. The use of a nonlinear normalization allows to disentangle in the spectra th

Michael H. Peters

It is well-known that the Liouville equation of statistical mechanics is restricted to systems where the total number of particles (N) is fixed. In this paper, we show how the Liouville equation can be extended to systems where the number of particles can vary, such as in open systems or in systems where particles can be annihilated or created. A general con

Jose F. Carinena, Arturo Ramos

In this paper we develop some group theoretical methods which are shown to be very useful for a better understanding of the properties of the Riccati equation and we discuss some of its integrability conditions from a group theoretical perspective. The nonlinear superposition principle also arises in a simple way.

Peter Kuchment, Sergei Levendorski

The paper contains a brief description of a simplified version of A. Sobolev's proof of absolute continuity of spectra of periodic magnetic Schrödinger operators. This approach is applicable to all periodic elliptic operators known to be of interest for math physics (including Maxwell), and in all these cases leads to the same model problem of complex an

Eugene Lerman, Susan Tolman

We provided two explicit formulas for the intersection cohomology (as a graded vector space with pairing) of the symplectic quotient by a circle in terms of the $S^1$ equivariant cohomology of the original symplectic manifold and the fixed point data. The key idea is the construction of a small resolution of the symplectic quotient.

A. K. Motovilov

The spectral problem (A + V(z))ψ=zψis considered with A, a self-adjoint operator. The perturbation V(z) is assumed to depend on the spectral parameter z as resolvent of another self-adjoint operator A': V(z)=-B(A'-z)^{-1}B^{*}. It is supposed that the operator B has a finite Hilbert-Schmidt norm and spectra of the operators A and A' are separated

Omar Foda, Keith S. M. Lee, Yaruslav Pugai, Trevor A. Welsh

We study combinatorial aspects of q-weighted, length-L Forrester-Baxter paths, P^{p, p&#39;}_{a, b, c}(L), where p, p&#39;, a, b, c \in Z_{+}, 0 < p < p&#39;, 0 < a, b, c < p&#39;, c = b \pm 1, L+a-b \equiv 0 (mod 2), and p and p&#39; are co-prime. We obtain a bijection between P^{p, p&#39;}_{a, b, c}(L) and partitions with certain prescribed hook difference

Ziv Ran

This paper gives a canonical construction, in terms of additive cohomological functors, of the universal formal deformation of a compact complex manifold without vector fields (more generally of a faithful $g$-module, where $g$ is a sheaf of Lie algebras without sections). The construction is based on a certain (multivariate) Jacobi complex $J(g)$ associatd

Katrin Becker, Melanie Becker

We consider the Matrix theory proposal describing eleven-dimensional Schwarzschild black holes. We argue that the Newtonian potential between two black holes receives a genuine long range quantum gravity correction, which is finite and can be computed from the supergravity point of view. The result agrees with Matrix theory up to a numerical factor which we

V. I. Fernández, C. M. Naón

We present a (1+1)-dimensional fermionic QFT with non-local couplings between currents. This model describes an ensemble of spinless fermions interacting through forward, backward and umklapp scattering processes. We express the vacuum to vacuum functional in terms of a non trivial fermionic determinant. Using path-integral methods we find a bosonic represen

I. Martin, A. Restuccia

We desribe the minimal configurations of the bosonic membrane potential, when the membrane wraps up in an irreducible way over $S^{1}\times S^{1}$. The membrane 2-dimensional spatial world volume is taken as a Riemann Surface of genus $g$ with an arbitrary metric over it. All the minimal solutions are obtained and described in terms of 1-forms over an associ

Davide Fioravanti, Marian Stanishkov

We generalize the dressing symmetry construction in mKdV hierarchy. This leads to non-local vector fields (expressed in terms of vertex operators) closing a Virasoro algebra. We argue that this algebra realization should play an important role in the study of 2D integrable field theories and in particular should be related to the Deformed Virasoro Algebra (D

Alexander Ushveridze

First examples of quasi-exactly solvable models describing spin-orbital interaction are constructed. In contrast with other examples of matrix quasi-exactly solvable models discussed in the literature up to now, our models admit (but still incomplete) sets of exact (algebraic) solutions.

Emil M. Prodanov, Siddhartha Sen

We show that when the induced parity breaking part of the effective action for the low-momentum region of U(1) x ... x U(1) Maxwell gauge field theory with massive fermions in 3 dimensions is coupled to a ϕ^4 scalar field theory, it is not possible to eliminate the screening of the long-range Coulomb interactions and get external charges confined in the brok

Michal Brhlik

The lightest neutralino in supersymmetric models with conserved R-parity is an attractive candidate for non-luminous matter in the universe. If relic neutralinos are indeed present as dark matter in our galaxy, they can be directly detected in scattering experiments. This could serve as an independent search channel for supersymmetry complementary to collide

Dieter Zeppenfeld, Kingman Cheung

Measurements of neutral current processes off the $Z$-peak are sensitive probes of new interactions, which may be induced by the exchange of new particles such as leptoquarks or extra $Z$&#39;s. This talk reviews the phenomenology of extra interactions in four-fermion processes and updates a global fit to contact terms in the neutral current sector.

Ulf-G. Meißner

I review the status of chiral perturbation theory in the one-nucleon sector and give some predictions to be tested. I then discuss various methods to go to higher energies (inclusion of the Delta(1232), dispersion relations) and also to higher precision (virtual photons and isospin violation).

Alan Kostelecky

A general Lorentz-violating extension of the minimal SU(3) x SU(2) x U(1) standard model is described, including both CPT-even and CPT-odd terms. Some theoretical properties and experimental implications are given. The extension can be regarded as a low-energy limit of a physically relevant Lorentz-covariant fundamental theory in which spontaneous Lorentz vi

C. Giunti

It is shown that the large angle MSW solution of the solar neutrino problem with a bi-maximal neutrino mixing matrix implies an energy-independent suppression of the solar nu_e flux. The present solar neutrino data exclude this solution of the solar neutrino problem at 99.6% CL.

Bodo Lampe, Ewald Reya

A review on the theoretical aspects and the experimental results of polarized deep inelastic scattering and of other hard scattering processes is presented. The following items are discussed: longitudinally polarized structure functions, results from the SLAC and CERN polarization experiments, the QCD interpretation and the LO and NLO Q2-evolution of g1, the

A. Sinkovics

I review the cancellation of non-perturbative 1/m_Q corrections to the heavy quark inclusive decay width. I summarize the results of an explicit second loop order calculation in perturbation theory which shows the absence of linear corrections when the decay width is expressed in terms of the short distance mass.

Haitham Zaraket

The Hard Thermal Loop expansion, is an attractive theory, but it reveals difficulties when one uses it as a perturbative scheme. To illustrate this we use the HTL expansion to calculate the two loop corrections for soft virtual photons. The resulting corrections are of the same order as the 1-loop correction.

T. Bhattacharya, S. Chandrasekharan, R. Gupta, W. Lee

We extend the application of vector and axial Ward identities to calculate $b_A$, $b_P$ and $b_T$, coefficients that give the mass dependence of the renormalization constants of the corresponding bilinear operators in the quenched theory. The extension relies on using operators with non-degenerate quark masses. It allows a complete determination of the $O(a)

T. Blum

I review domain wall fermions in vector gauge theories. Following a brief introduction, the status of lattice calculations using domain wall fermions is presented. I focus on results from QCD, including the light quark masses and spectrum, weak matrix elements, the $n_f=2$ finite temperature phase transition, and topology and zero modes and conclude with top

The OPAL Collaboration, G. Abbiendi et al

The inclusive charm hadron semileptonic branching fractions B(c to e) and B(c to mu) in Z to ccbar events have been determined using 4.4 million hadronic Z decays collected with the OPAL detector at LEP. A charm-enriched sample is obtained by selecting events with reconstructed D*+- mesons. Using leptons found in the hemisphere opposite that of the D*+- meso

Roumen Borissov, Sameer Gupta

One of the main results in canonical quantum gravity is the introduction of spin network states as a basis on the space of kinematical states. To arrive at the physical state space of the theory though we need to understand the dynamics of the quantum gravitational states. To this aim we study a model in which we allow for the spins, labeling the edges of sp

Carmen Molina-Paris, Matt Visser

We investigate the minimal conditions under which the creation of our universe might arise due to a &#34;bounce&#34; from a previous collapse, rather than an explosion from a big-bang singularity. Such a bounce is sometimes referred to as a Tolman wormhole. We subject the bounce to a general model-independent analysis along the lines of that applied to the M

R. J. van Glabbeek

Flat iteration is a variation on the original binary version of the Kleene star operation P*Q, obtained by restricting the first argument to be a sum of atomic actions. It generalizes prefix iteration, in which the first argument is a single action. Complete finite equational axiomatizations are given for five notions of bisimulation congruence over basic CC

Chen-Shan Chin, Marcel den Nijs

We present numerical Monte Carlo results for the stationary state properties of KPZ type growth in two dimensional surfaces, by evaluating the finite size scaling (FSS) behaviour of the 2nd and 4th moments, $W_2$ and $W_4$, and the skewness, $W_3$, in the Kim-Kosterlitz (KK) and BCSOS model. Our results agree with the stationary state proposed by Lässig. The

Arkadiusz Wojs, Pawel Hawrylak, John J. Quinn

Systems of up to twelve electrons and six holes on the Haldane sphere are studied by exact numerical diagonalization. The low lying states of the system involve bound excitonic complexes such as (X^n)-. The angular momenta of these complexes and the pseudopotentials describing their interaction are determined. The similarity to the electron pseudopotential s

Arkadiusz Wojs, Pawel Hawrylak, John J. Quinn

We study the system of up to four negatively charged magneto-excitons (X-&#39;s) in the spherical geometry, using the exact-diagonalization techniques. At low energies, X-&#39;s are bound and behave like charged particles without internal dynamics. The pseudopotential describing X-:X- scattering is almost identical to that of electrons and the low-lying few

Frantisek Slanina

A model which accounts for cracking avalanches in piles of grains subject to external load is introduced and numerically simulated. The stress is stochastically transferred from higher layers to lower ones. Cracked areas exhibit various morphologies, depending on the degree of randomness in the packing and on the ductility of the grains. The external force n

Arkadiusz Wojs, John J. Quinn

The success of the mean field composite Fermion (MFCF) picture in predicting the lowest energy band of angular momentum multiplets in fractional quantum Hall systems cannot be found in a cancellation between the Coulomb and Chern--Simons interactions beyond the mean field, due to their totally different energy scales. We show that the MFCF approximation can

Arkadiusz Wojs, John J. Quinn

The mean field composite Fermion (MFCF) picture has been qualitatively successful when applied to electrons (or holes) in the lowest Landau level. Because the energy scales associated with Coulomb interactions and with Chern-Simons gauge field interactions are different, there is no rigorous justification of the qualitative success of the MFCF picture. Here

Stephen Bigelis, Emilio N. M. Cirillo, Joel L. Lebowitz, Eugene R. Speer

We consider the problem of metastability in a probabilistic cellular automaton (PCA) with a parallel updating rule which is reversible with respect to a Gibbs measure. The dynamical rules contain two parameters $β$ and $h$ which resemble, but are not identical to, the inverse temperature and external magnetic field in a ferromagnetic Ising model; in particul

K. Tsemekhman, V. Tsemekhman, C. Wexler

We present a consistent treatment of the quantum Hall effect within the electrostatic approximation. We derive the form of the density of states (DOS) which differs from the usual gaussian shape valid for non-interacting electrons. Below a crossover temperature, this DOS gradually transforms into the non-interacting DOS near the Fermi energy. We obtain an es

Victor Barzykin, Ian Affleck

Corrections to the asymptotic correlation function in a Heisenberg spin-1/2 antiferromagnetic spin chain are known to vanish slowly (logarithmically) as a function of the distance r or the chain size L. This leads to significant differences with numerical results. We calculate the sub-leading logarithmic corrections to the finite-size correlation function, u

Ariel Dobry, David Ibaceta

We reconsider the excitation spectra of a dimerized and frustrated antiferromagnetic Heisenberg chain. This model is taken as the simpler example of compiting spontaneous and explicit dimerization relevant for Spin-Peierls compounds. The bosonized theory is a two frequency Sine-Gordon field theory. We analize the excitation spectrum by semiclassical methods.

Ph. A. Martin, J. Piasecki

One considers the motion of a test particle in an homogeneous fluid in equilibrium at temperature $T$, undergoing dissipative collisions with the fluid particles. It is shown that the corresponding linear Boltzmann equation still posseses a stationary Maxwellian velocity distribution, with an effective temperature smaller than $T$. This effective temperature

Ph. A. Martin, J. Piasecki

Propagation of a particle accelerated by an external field through a scattering medium is studied within the generalized Lorentz model allowing inelastic collisions. Energy losses at collisions are proportional to $(1-α^{2})$, where $0\leα\le 1$ is the restitution coefficient. For $α=1$ (elastic collisions) there is no stationary state. It is proved in one d

Johann Kroha

We show that quantum correlations induced by electron-electron interactions in the presence of random impurity scattering can play an important role in the thermal stabilization of amorphous Hume-Rothery systems: When there is strong backscattering off local, concentrical ion clusters, the static electron density response $χ(0,q)$ acquires a powerlaw diverge

H. B. Sun, G. J. Milburn

A quantum Markovian master equation is derived to describe the current noise in resonant tunnelling devices. This equation includes both incoherent and coherent quantum tunnelling processes. We show how to obtain the population master equation by adiabatic elimination of quantum coherences in the presence of elastic scattering. We calculate the noise spectru

Yoshiyuki Y. Yamaguchi, Yasusada Nambu

We investigate perturbed Hamiltonian systems with two degrees of freedom by renormalization group method, which derives a reduced equation called renormalization group equation (RGE) by handling secular terms. We found that RGE is not always a Hamiltonian system. The necessary and sufficient condition that RGE becomes a Hamiltonian system up to the second le

James R. Murray, Martijn de Kool, Jianke Li

We numerically investigate the hydrodynamics of accretion disk reversal and relate our findings to the observed spin-rate changes in the accreting X-ray pulsar GX~1+4. In this system, which accretes from a slow wind, the accretion disk contains two dynamically distinct regions. In the inner part viscous forces are dominant and disk evolution occurs on a visc

Eliot Quataert, Ramesh Narayan

Using mean field MHD, we discuss the energetics of optically thin, two temperature, advection-dominated accretion flows (ADAFs). If the magnetic field is tangled and roughly isotropic, flux freezing is insufficient to maintain the field in equipartition with the gas. In this case, we expect a fraction of the energy generated by shear in the flow to be used t

Christopher W. Mauche

An admittedly pedantic but hopefully useful and informative analysis is presented of the EUVE 70--180 Angstrom spectra of nine polars. These spectra are fit with three different models---a blackbody, a pure-H stellar atmosphere, and a solar abundance stellar atmosphere---to reveal the presence of spectral features such as absorption lines and edges, and to i

K. Bischoff, W. Pietsch, T. Boller, S. Döbereiner

We present the results of a program to identify so far unknown active nuclei (AGN) in galaxies. Candidate galactic nuclei have been selected for optical spectroscopy from a cross-correlation of the ROSAT all sky survey (RASS) bright source catalog with optical galaxy catalogs. In this paper we present results from the second optical observing run.

W. Kollatschny, K. Bischoff

We present results of optical long-term variability campaigns (10 - 20 years) of the two Seyfert galaxies NGC 7603 and Mrk 110. The variations of the continuum, of the individual broad line intensities and of their line profiles are investigated in detail and compared to line profile variations in NGC 5548 and NGC 4593. Individual emission line profiles vary

M. R. Burleigh, M. A. Barstow

We report the identification, in an Extreme Ultraviolet Explorer (EUVE) spectrum, of a hot white dwarf companion to the 3rd magnitude late-B star Theta Hya (HR3665, HD79469). This is the second B star + white dwarf binary to be conclusively identified; Vennes, Berghofer and Christian (1997), and Burleigh and Barstow (1998) had previously reported the spectro

G. S. Bisnovatyi-Kogan

Accretion disc theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disc. One of the most important new invention of this theory was a phenomenological treatment of the turbulent viscosity, known as &#39;&#39;alpha&#39;&#39; prescription, when the (r$ϕ$) compo

M. R. Burleigh, S. Jordan, W. Schweizer

We present phase resolved FUV HST FOS spectra of the rapidly rotating, highly magnetic white dwarf RE J0317-853. Using these data, we construct a new model for the magnetic field morphology across the stellar surface. From an expansion into spherical harmonics, we find the range of magnetic field strengths present is 180-800MG. For the first time we could id

Neven Bilic, Raoul D. Viollier

It is shown, in the framework of the Thomas-Fermi model at finite temperature, that a cooling non-degenerate gas of massive neutrinos will, at a certain temperature, become unstable and undergo a first-order phase transition in which quasi-degenerate supermassive neutrino stars are formed through gravitational collapse. For neutrinos in the mass range of 10

A. Finoguenov, C. Jones, W. Forman, L. David

In this paper we analyze the diffuse X-ray coronae surrounding the elliptical galaxy NGC5846, combining measurements from two observatories, ROSAT and ASCA. We map the gas temperature distribution and find a central cool region within an approximately isothermal gas halo extending to a radius of about 50 kpc, and evidence for a temperature decrease at larger

E. Branchini, C. S. Frenk L. Teodoro, I. Schmoldt, G. Efstathiou

We present a self-consistent nonparametric model of the cosmic velocity field based on the spatial distribution of IRAS galaxies in the recently completed all-sky PSC$z$ redshift survey. The most streaking feature of the PSCz model velocity field is a coherent large-scale streaming motion along the Perseus Pisces, Local Supercluster, Great Attractor and Shap

Stefanie Komossa, Jochen Greiner

Warm absorbers are an important new tool for investigating the conditions within the central regions of active galaxies. They have been observed in ~50% of the well-studied Seyfert galaxies and have also been detected in quite a number of Narrow-line Seyfert 1 galaxies (NLSy1). Here, we present a study of the X-ray properties of several NLSy1s with focus on

I. G. Kovalenko, Yu. A. Shchekinov

Nonlinear evolution of one-dimensional planar perturbations in an optically thin radiatively cooling medium in the long-wavelength limit is studied numerically. The accepted cooling function generates in thermal equilibrium a bistable equation of state $P(ρ)$. The unperturbed state is taken close to the upper (low-density) unstable state with infinite compre

Srdjan Samurovic, Milan M. Cirkovic

By extrapolating the accumulated low-redshift data on the absorption radius of galaxies and its luminosity scaling, it is possible to predict the total absorption cross-section of the gas associated with collapsed structures in the universe at any given epoch. This prediction can be verified observationally through comparison with the well-known spatial dist

P. Papaderos, K. J. Fricke

We present first results of a study devoted to the analysis of the X-ray emission as tracer of activity and diagnostic tool for the structural properties of Blue Compact Dwarf Galaxies. The case of Henize 2-10 is being reviewed, and first trends are discussed.

W. Pietsch, G. Trinchieri, A. Vogler

We report the results of the spatial and spectral analysis of the ROSAT HRI and PSPC observations of the edge-on spiral galaxy NGC 3079. We detected several sources in the field of NGC 3079 with both PSPC and HRI, and complex emission from the inner 5&#39; around NGC 3079. We have identified possible counterparts for several of the sources outside NGC 3079 b

Q. -S. Gu, J. -H. Huang, H. -J. Su, Z. -H. Shang

We present optical spectra for new infrared Seyfert galaxies obtained with the 2.16m telescope at Beijing Astronomical Observatory (BAO). After wavelength and flux calibration, they are classified by the degree of nuclear activity: nine Seyfert 2 and three Seyfert 3 galaxies. In addition, by using the data from de Grijp et al.(1992), we find that (1) there e

Q. -S. Gu, J. -H. Huang, L. Ji

In this paper, we report our preliminary results on enhanced star formation activity in Seyfert 2 galaxies. By re-analysing the Tully-Fisher relation for Whittle(1992)&#39;s sample and for a Seyfert 2s&#39; sample selecting from Veron-Cetty & Veron (1996), we find that (1) almost all Seyfert 2 galaxies with circumnuclear star formation have a ratio of far in

Jeroen P. E. Gerritsen, W. J. G. de Blok

We present N-body simulations of Low Surface Brightness (LSB) galaxies and their Interstellar Medium to investigate the cause for their low star formation rates (SFR).Due to their massive halos, stellar disks of LSB galaxies are very stable and thin. Lack of dust makes the projected edge-on surface brightness of LSB galaxies comparable to the projected edge-

Takashi Hamana

Weyl focusing effects on the image magnifications are investigated by using the multiple gravitational lens theory. We focus on the gravitational lensing effects due to the small scale virialized objects, such as galaxies and clusters of galaxies. We consider a simple model of an inhomogeneous universe. The matter distribution in the universe is modeled by r

John C. Lattanzio

We summarise the main properties of Asymptotic Giant Branch stars, including their structure, evolution and nucleosynthesis. The main physical mechanisms are outlined, as are the uncertainties. In keeping with the multi-disciplinary nature of this meeting, this paper is designed for those who are not experts in stellar structure.

Jacob Mostovoy

A rope is a non-singular embedding of a closed interval into R^3, which sends the ends of the interval to some fixed points A and B such that |AB|=1. A rope is short if its length is less than 3. The main result of the paper is that the fundamental group of the space of short ropes is naturally isomorphic to the group completion of the semigroup of knots.

Jiunn-Wei Chen

The differential cross section for gamma-deuteron Compton scattering from a tensor polarized deuteron is computed in an effective field theory. The first non-vanishing contributions to this differential cross section are the interference terms between the leading electric coupling diagrams and the subleading single potential pion exchange diagrams or the sub

I. Bakas, E. Floratos, A. Kehagias

We construct eight-dimensional gravitational instantons by solving appropriate self-duality equations for the spin-connection. The particular gravitational instanton we present has $Spin(7)$ holonomy and, in a sense, it is the eight-dimensional analog of the Eguchi-Hanson 4D space. It has a removable bolt singularity which is topologically S^4 and its bounda

Feng Xu

All unitary Rational Conformal Field Theories (RCFT) are conjectured to be related to unitary coset Conformal Field Theories, i.e., gauged Wess-Zumino-Witten (WZW) models with compact gauge groups. In this paper we use subfactor theory and ideas of algebraic quantum field theory to approach coset Conformal Field Theories. Two conjectures are formulated and t

Xiangdong Shi, George M. Fuller

We propose a new and unique dark matter candidate: $\sim 100$ eV to $\sim 10$ keV sterile neutrinos produced via lepton number-driven resonant MSW (Mikheyev-Smirnov-Wolfenstein) conversion of active neutrinos. The requisite lepton number asymmetries in any of the active neutrino flavors range from 10$^{-3}$ to 10$^{-1}$ of the photon number - well within pri

Xiangdong Shi, George M. Fuller

We discuss Big Bang Nucleosynthesis constraints on maximal $ν_μ\leftrightarrowν_s$ mixing. Vacuum $ν_μ\leftrightarrowν_s$ oscillation has been proposed as one possible explanation of the Super Kamiokande atmospheric neutrino data. Based on the most recent primordial abundance measurements, we find that the effective number of neutrino species for Big Bang Nu

E. Schmidt, L. Knoell, D. -G. Welsch

The quantum statistics of damped optical solitons is studied using cumulant-expansion techniques. The effect of absorption is described in terms of ordinary Markovian relaxation theory, by coupling the optical field to a continuum of reservoir modes. After introduction of local bosonic field operators and spatial discretization pseudo-Fokker-Planck equations

F. M. Steffens, K. Tsushima, A. W. Thomas, K. Saito

The determination of the spin distribution functions for the neutron requires an understanding of the changes induced by a nuclear medium. We present the first estimates of the changes induced in the spin-dependent, valence parton distributions of the proton and neutron bound in $^3$He and $^6$Li. For $^3$He the result is quite reassuring, in that the off-sh

P. M. Cowdall

The maximal SO(5) gauged D=7 supergravity is dimensionally reduced to six dimensions yielding a new SO(5) gauged D=6 model. It is shown that, unlike in D=7, the SO(5) gauge coupling constant can be taken to zero to yield the maximally extended supergravity in six dimensions. It is also shown that the limit of D=5 N=4 SU(2)xU(1) gauged supergravity in which t

Kikuo Harigaya

A phenomenological coupled exciton model is proposed in order to characterize optical excitations in extended dendrimers. An onsite exciton state is assigned at each phenyl rings and a nearest neighbor hopping integral which obeys the Gaussian distribution is considered between the exciton states. The decreasing optical excitation energy with respect to the

Lorenzo Fatibene, Marco Ferraris, Mauro Francaviglia, Marco Raiteri

We criticize and generalize some properties of Noether charges presented in a paper by V. Iyer and R. M. Wald and their application to entropy of black holes. The first law of black holes thermodynamics is proven for any gauge-natural field theory. As an application charged Kerr-Newman solutions are considered. As a further example we consider a (1+2) black

I. Bandos, E. Ivanov, A. Kapustnikov, S. Ulanov

We present the general solution of the system of coupled nonlinear equations describing dynamics of $D$--dimensional bosonic string in the geometric (or embedding) approach. The solution is parametrized in terms of two sets of the left- and right-moving Lorentz harmonic variables providing a special coset space realization of the product of two (D-2)- dimens

Qiong-gui Lin

We calculate the probability of electron-positron pair creation in vacuum in 3+1 dimensions by an external electromagnetic field composed of a constant uniform electric field and a constant uniform magnetic field, both of arbitrary magnitudes and directions. The same problem is also studied in 2+1 and 1+1 dimensions in appropriate external fields and similar

V. Ravindran, W. L. van Neerven

The sentence, 7th line below Eq. (28), starting with &#34;Further we exclude all interference terms ....&#34; is wrong and has been corrected. Eq. (33) : f_k^{l,(i)} -> h_k^{l,(i)} i=0,1 Second line below Eq. (33) m_bar(m)=m is replaced by m_bar(μ_0)=μ_0 with μ_0=4.10 GeV and μ_0=166.1 GeV for bottom and top respectively. The numbers in the third column of t

Fabrizio Cei

We report on the search for Rare Particles (Magnetic Monopoles, Nuclearites, Weakly Interacting Massive Particles and Lightly Ionizing Particles) with the MACRO detector. For magnetic monopoles (the main goal of the experiment) our limit is about 0.4 times the Parker bound for monopole velocities between 10^{-4} and 10^{-1}.

Gia Dvali, Yosef Nir

Moduli are generic in string (M) theory. In a large class of gauge-mediated Supersymmetry breaking models, the fermionic components of such fields have very light masses, around the eV scale, and non-negligible mixing with active neutrinos, of order $10^{-4}$. Consequently, these fermions could play the role of sterile neutrinos to which active neutrinos osc

K. Tsushima, D. H. Lu, A. W. Thomas, K. Saito

We show that the D^- meson will form narrow bound states with ^{208}Pb. Mean field potentials for the D^0, D^0-bar and D^- in ^{208}Pb are calculated self-consistently using the quark-meson coupling (QMC) model in local density approximation. The meson-^{208}Pb bound state energies are then calculated by solving the Klein-Gordon equation with these potential

John Palmer

We introduce a family of local deformations for meromorphic connections on the Riemann sphere in the neighborhood of a higher rank (simple) singularity. Following a scheme introduced by Malgrange we use these local models to prove that the zeros of the tau function introduced by Jimbo, Miwa and Ueno occur precisely at those points in the deformation space at

Giuseppe Castagnoli

The topical quantum computation paradigm is a transposition of the Turing machine into the quantum framework. Implementations based on this paradigm have limitations as to the number of: qubits, computation steps, efficient quantum algorithms (found so far). A new exclusively quantum paradigm (with no classical counterpart) is propounded, based on the specul

Robert B. Griffiths

John Wheeler devised a gedanken experiment in which a piece of apparatus can be altered just before the arrival of particle, and this ``delayed choice&#39;&#39; can, seemingly, alter the quantum state of the particle at a much earlier time, long before the choice is made. A slightly different gedanken experiment, which exhibits the same conceptual difficulty

Michael J. York

We discuss the conditions under which identical particles may yet be distinguishable and the relationship between particle permutation and exchange. We show that we can always define permutation-symmetric state vectors. When the particles are completely indistinguishable, then exchange is equivalent to permutation and therefore the exchange eigenvalue for su

Carsten Henkel, Vahid Sandoghdar

We present an analytical approach to the calculation of the linewidth and lineshift of an atom or molecule in the near field of a structured dielectric surface. For soft surface corrugations with amplitude lambda/50, we find variations of the linewidth in the ten percent region. More strikingly, the shift of the molecular resonance can reach several natural

A. P. Potylitsin

The paper considers the process of Thomson scattering of coherent diffraction radiation (CDR) produced by the preceding bunch of the accelerator on one of the following bunches. It is shown that the yield of scattered hard photons is proportional to N$_e^3$, where N$_e$ is the number of electrons per bunch. A geometry is chosen for the CDR generation and an

S. G. Porsev, Yu. G. Rakhlina, M. G. Kozlov

We calculate energies and hyperfine structure constants A and B for low-lying levels of $^{173}$Yb. The latter is treated as a two-electron atom. To account for valence-valence correlations the configuration interaction method is used. Valence-core correlations are accounted for within the many-body perturbation theory which is used to construct effective tw

T. Ostoma, M. Trushyk

A new formulation of Special Relativity is described. It is based on Cellular Automata theory and on a new theory of inertia called Quantum Inertia. The universe consists of a huge 3D array of cells given by C(x,y,z), whose numeric states are updated by every new CA clock period. The numeric state of the cells depends on the contents of the imediate neigbour

T. A. Bobrova, L. I. Ognev

A new method for investigation of x-ray propagation in a rough narrow dielectric waveguide is proposed on the basis of the numerical integration of the quazioptical equation. In calculations a model rough surface was used with the given statistical properties. It was shown that the losses in the narrow waveguides strongly depend on the wall roughness and on

A. Parreño, A. Ramos, N. G. Kelkar, C. Bennhold

The weak production of Lambdas in nucleon-nucleon scattering is studied in a meson-exchange framework. The weak transition operator for the $NN \to N Λ$ reaction is identical to a previously developed weak strangeness-changing transition potential $ΛN \to NN$ that describes the nonmesonic decay of hypernuclei. The initial $NN$ and final $YN$ state interactio

A. M. Sandorfi, S. Hoblit, J. Tonnison

Multipole analyses of the p(g,pi0), p(g,pi+) and p(g,g) reactions are carried out using different data sets. With sufficient constraints from polarization observables, the ratio of E2/M1 transition amplitudes for N->delta (EMR) appears to be largely insensitive to differences between recent p(g,pi0) cross section measurements. We deduce a current best estima

Georg Wagner

Radiative decays of decuplet hyperons and octet hyperon charge radii are evaluated in a chiral constituent quark model emphasizing the role of exchange currents. Exchange currents largely cancel for the M1 decay amplitudes, while they dominate the E2 amplitude. Due to the pseudoscalar meson cloud the charge radii of Sigma^- and Xi^- are almost as large as th

S. Majid

The cross coproduct braided group $Aut(C) \rcocross B$ is obtained by Tannaka-Krein reconstruction from $C^B\to C$ for a braided group $B$ in braided category $C$. We apply this construction to obtain partial solutions to two problems in braided group theory, namely the tensor problem and the braided double. We obtain $Aut(C)\rcocross Aut(C)\isom Aut(C)\lcro