August 2000 arXiv papers — page 4

Karl-Georg Schlesinger

We start from a quantum computational principle suggested for string theory in a previous paper and discuss how it might lead to a dynamical principle implying the correct classical gravitational limit. Besides this, we briefly look at some structural properties of moduli space.

Karl-Georg Schlesinger

String theory is accused by some of its critics to be a purely abstract mathematical discipline, having lost the contact to the simple yet deeply rooted questions which physics provided until the beginning of this century. We argue that, in contrary, there are indications that string theory might be linked to a fundamental principle of a quantum computationa

D. K. Park, H. J. W. Müller-Kirsten

The calculation of absorption cross sections for minimal scalars in supergravity backgrounds is an important aspect of the investigation of AdS/CFT correspondence and requires a matching of appropriate wave functions. The low energy case has attracted particular attention. In the following the dependence of the cross section on the matching point is investig

T. S. Evans, H. F. Jones, D. Winder

We use an optimised hopping parameter expansion for the free energy (linear delta expansion) to study the phase transitions at finite temperature and finite charge density in a global U(1) scalar Higgs sector on the lattice at large lattice couplings. We are able to plot out phase diagrams in lattice parameter space and find that the standard second-order ph

D. Drechsel, S. S. Kamalov, L. Tiator

The spin structure of the nucleon resonance region is analyzed on the basis of our phenomenological model MAID. Predictions are given for the Gerasimov-Drell-Hearn sum rule as well as generalized integrals over spin structure functions. The dependence of these integrals on momentum transfer is studied and rigorous relationships between various definitions of

S. N. Gninenko, N. V. Krasnikov

Combined results on $ν_μ\to ν_τ$ oscillations and $νe$-scattering from the Super-Kamiokande and LAMPF experiments, respectively, limit the Dirac $ν_τ$ diagonal magnetic moment to $μ_{ν_τ} < 1.9\times 10^{-9} μ_{B}$. For the scheme with 3 Majorana neutrinos the LAMPF results allow the limitation of effective $ν_τ$ magnetic moment to $μ_{ν_τ} < 7.6 \times 10^{

C. Arias Tobena, M. F. Gari

In the present paper we extend the Schwinger model of the nucleon to the inclusion of loop corrections. Starting from a chiral model of nucleon and delta for the mesons $π,ρ$ and $A_1$ we extend our nonperturbative sefconsistent regularisation scheme to the calculation of the nucleon form factors. Chiral symmetry requires loops according to the interactions

F. Yuan, K. T. Chao

Direct $J/ψ$ and $ψ&#39;$ production rates at Tevatron are calculated in the $k_t$-factorization approach within the color-singlet model. In this approach, the production rates are enhanced by a factor of 20 compared to the naive collinear parton model. However, the theoretical predictions are still below the experimental data by at least one order of magnit

A. G. Grozin

Extended version of lectures given at the University of Karlsruhe and at Calc-2000 school in Dubna. Properties of HQET as a field theory, methods of calculation of HQET diagrams and some simple applications are explained in detail. These lectures can be used as an additional chapter with any modern QCD textbook.

O. V. Kancheli

The Froissart asymptotic behavior of cross-sections is usually considered in a parton picture as corresponding to the collision of two almost black disks filled with partons. In this article we mainly concentrate on the examination of the local transparency of such F-disks. We discuss how is it possible to guarantee the boost-invariance of the reciprocal tra

Andrzej J. Buras, Robert Fleischer

As we pointed out recently, the neutral decays $B_d\toπ^\mp K^\pm$ and $B_d\toπ^0K$ may provide non-trivial bounds on the CKM angle $γ$. Here we reconsider this approach in the light of recent CLEO data, which look very interesting. In particular, the results for the corresponding CP-averaged branching ratios are in favour of strong constraints on $γ$, where

Aiichi Iwazaki

We propose a model in which ultra high energy cosmic rays and gamma ray bursts are produced by collisions between neutron stars and axion stars. The acceleration of such a cosmic ray is made by the electric field, $\sim 10^{15} (B/10^{12} {G}) {eV} {cm}^{-1}$, which is induced in an axion star by relatively strong magnetic field $B>10^{12}$ G of a neutron st

Y. Suzuki

Possibility to use ultra pure liquid Xenon as a low energy solar neutrino detector by means of $ν$+e scatterings is evaluated. A possible detector with 10 tons of fiducial volume will give $\sim$14 events for pp-neutrinos and $\sim$6 events for $^{7}$Be neutrinos with the energy threshold at 50 keV. The detector can be built with known and established techno

Gordon L. Kane

After an introduction recalling that we expect low energy supersymmetry to be part of our description of nature because of considerable indirect evidence and successful predictions, and a discussion of the essential role of data for formulating and testing string theory, these lectures focus on the role of the supersymmetry soft-breaking Lagrangian in connec

J. Chizma, G. Karl

We discuss the agreement in sign between the recently measured strange contribution to the proton magnetic moment and SU(3) based fits to baryon octet magnetic moments.

Sheldon Stone

Recent results include the measurement of B->D(*)pi+pi-pi-pi0 decays, with rates of ~1.8% observation of a significant omega pi^- substructure that appears to result from the decay of the rho&#39; resonance, whose mass and width we determine as 1418 MeV and 382 MeV, respectively. Using B to charmonium decays we find that the neutral B fraction in Y(4S) decay

J. W. Maluf, J. F. da Rocha-Neto, T. M. Toribio, K. H. Castello-Branco

The Hamiltonian formulation of the teleparallel equivalent of general relativity without gauge fixing has recently been established in terms of the Hamiltonian constraint and a set of six primary constraints. Altogether, they constitute a set of first class constraints. In view of the constraint structure we establish definitions for the energy, momentum and

R. B. Mann, G. Potvin, M. Raiteri

A general definition of energy is given, via the Nöther theorem, for the N-body problem in (1+1) dimensional gravity. Within a first-order Lagrangian framework, the density of energy of a solution relative to a background is identified with the superpotential of the theory. For specific applications we reproduce the expected Hamiltonian for the motion of N p

Peter B. Weichman, Alexa W. Harter, David L. Goodstein

We review a striking array of recent experiments, and their theoretical interpretations, on the superfluid transition in $^4$He in the presence of a heat flux, $Q$. We define and evaluate a new set of critical point exponents. The statics and dynamics of the superfluid-normal interface are discussed, with special attention to the role of gravity. If $Q$ is i

Heng Fan, Miki Wadati

We investigate the generalized supersymmetric $t-J$ model with boundary impurities in different gradings. All three different gradings: fermion, fermion, boson (FFB), boson, fermion, fermion (BFF) and fermion, boson, fermion (FBF), are studied for the generalized supersymmetric $t-J$ model. Boundary K-matrix operators are found for the different gradings. By

Philippe Curty, Hans Beck

The d-dimensional complex Ginzburg-Landau (GL) model is solved according to a variational method by separating phase and amplitude. The GL transition becomes first order for high superfluid density because of effects of phase fluctuations. We discuss its origin with various arguments showing that, in particular for d = 3, the validity of our approach lies pr

M. V. Cheremisin

We demonstrate that in strong quantum limit the thermoelectric Peltier effect could define the longitudinal resistivity of dissipationless two-dimensional electron(hole) gas. The current results in heating(cooling) at first(second) Hall bar sample contact due to Peltier effect. At small current the contacts temperatures are different, the temperature gradien

Frank Eurich, Philipp Maass

A soft ellipsoid model for Gaussian polymer chains is studied, following an idea proposed by Murat and Kremer [J. Chem. Phys. 108, 4340 (1998)]. In this model chain molecules are mapped onto ellipsoids with certain shapes, and to each shape a monomer density is assigned. In the first part of the work, the probabilities for the shapes and the associated monom

Achille Giacometti

The existence and stability of the universality class associated to local minimal energy landscapes is investigated. Using extensive numerical simulations, we first study the dependence on a parameter $γ$ of a partial differential equation which was proposed to describe the evolution of a rugged landscape toward a local minimum of the dissipated energy. We t

C. Raman, R. Onofrio, J. M. Vogels, J. R. Abo-Shaeer

We study dissipation in a dilute Bose gas induced by the motion of a macroscopic object. A blue-detuned laser beam focused on the center of a trapped gas of sodium atoms was scanned both above and below the BEC transition temperature. The measurements allow for a comparison between the heating rates for the superfluid and normal gas.

Akinori Nishino, Miki Wadati

We construct bosonic and fermionic eigenstates for the generalized Sutherland models associated with arbitrary reduced root systems respectively, through W-symmetrization and W-anti-symmetrization of Heckman-Opdam&#39;s nonsymmetric Jacobi polynomials. Square norms of the nonsymmetric Heckman-Opdam polynomials are evaluated from their Rodrigues formulae. The

Denis J. Evans, Debra J. Searles, Emil Mittag

For thermostatted dissipative systems the Fluctuation Theorem gives an analytical expression for the ratio of probabilities that the time averaged entropy production in a finite system observed for a finite time, takes on a specified value compared to the negative of that value. Hitherto it had been thought that the presence of some thermostatting mechanism

Patrick A. Lee, Xiao-Gang Wen

In underdoped cuprates the normal state is highly anomalous and is characterized as a pseudogap phase. The question of how to describe the ``normal&#39;&#39; core of a superconducting vortex is an outstanding open problem. We show that the SU(2) formulation of the t-J model provides a description of the normal state as well as the vortex core. Interestingly,

P. Chaddah, M. Manekar

We present a model in which metastable supercooled phase and stable equilibrium phase of vortex matter coexist in different regions of a sample. Minor hysteresis loops are calculated with the simple assumption of the two phases of vortex matter having field-independent critical current densities. We use our earlier published ideas that the free energy barrie

T. V. Shahbazyan, N. Primozich, I. E. Perakis

We study theoretically the ultrafast nonlinear optical response of quantum well excitons in a perpendicular magnetic field. We show that for magnetoexcitons confined to the lowest Landau levels, the third-order four-wave-mixing (FWM) polarization is dominated by the exciton-exciton interaction effects. For repulsive interactions, we identify two regimes in t

P. Valageas, R. Schaeffer

We use a unified analytical formulation for the multiplicity functions of clusters and galaxies which is free from the cloud-in-cloud problem encountered in earlier approaches and well adapted to the description of the non-linear clustering features. It is especially suited to simultaneously describe rich clusters, groups and galaxies, consistently with the

Jon A. Holtzman, Graeme H. Smith, Carl Grillmair

We present HST/WFPC2 photometry of the central regions of the Phoenix dwarf. Accurate photometry allows us to: 1) confirm the existence of the horizontal branch previously detected by ground-based observations, and use it to determine a distance to Phoenix, 2) clearly detect the existence of multiple ages in the stellar population of Phoenix, 3) determine a

F. Cuisinier, J. Koppen, A. Acker, W. J. Maciel

We compare the populations of Red Giant stars and Planetary Nebulae in the Galactic Bulge, in the light of recent determinations of their abundances patterns. We find both populations to be compatible. From the planetary nebulae, we find evidences that the Bulge did not form stars recently. The whole abundances pattern remains however puzzling, some elements

France Allard, Peter H. Hauschildt, David Schwenke

We compare the structures of model atmospheres and synthetic spectra calculated using different line lists for TiO and water vapor. We discuss the effects of different line list combinations on the model strutures and spectra for both dwarf and giant stars. It is shown that recent improvements result in significantly improved spectra, in particular in the op

France Allard, Peter H. Hauschildt, Andreas Schweitzer

We present a grid of spherically symmetric model atmospheres for young pre-MS stars. This grid spans the parameter range $2000\K \leq \Teff \leq 6800\K$ and $2.0 \leq \logg \leq 3.5$ for $M=0.1\Msun$, appropriate for low mass stars and brown dwarfs. A major improvement is the replacement of TiO and \water line lists with the newer line list calculated by the

A. M. Khokhlov

The paper describes a physical model and numerical algorithm for modeling Type Ia supernova (SNIa) explosions in three dimensions and presents first results of modeling a deflagration explosion in a nonrotating, Chandrasekhar-mass carbon-oxygen (CO) white dwarf. Simulations show that the turbulent flame speed grows exponentially, reaches approximately 30% of

R. J. Brunner, L. M. Lubin

Clusters of galaxies are important laboratories for understanding both galaxy evolution and constraining cosmological quantities. Any analysis of clusters, however, is best done when one can reliably determine which galaxies are members of the cluster. While this would ideally be done spectroscopically, the difficulty in acquiring a complete sample of spectr

Anlaug Amanda Kaas, Sylvain Bontemps

We summarize the main results of a mid-IR photometric survey with ISO for a few nearby embedded clusters. The sensitivity and spatial resolution of ISOCAM provided a wonderful tool for studies of the youngest stellar clusters, which are still deeply embedded in their parent molecular clouds. Mid-IR photometry is found to be extremely efficient in finding all

A. Ptak

Low-luminosity AGN (with X-ray luminosity < 1e42 ergs/s) far outnumber ordinary AGN, and are therefore perhaps more relevant to our understanding of AGN phenomena and the relationship between AGN and host galaxies. Many normal galaxies harbor LINER and starburst nuclei, which, together with LLAGN, are a class of ``low-activity&#39;&#39; galaxies that have a

A. E. Wehrle, B. G. Piner, S. C. Unwin, A. C. Zook

We present results of long-term high-frequency VLBI monitoring of the relativistic jet in 3C279, consisting of 18 epochs at 22 GHz from 1991 to 1997 and 10 epochs at 43 GHz from 1995 to 1997. Three major results of this study are: apparent speeds measured for six superluminal components range from 4.8 to 7.5 c (H_{0}=70 km s^{-1} Mpc^{-1}, q_{0}=0.1), variat

Jacco Vink, Fabrizio Bocchino, Francesco Damiani, Jelle S. Kaastra

We report on the discovery of an unresolved X-ray source inside the supernova remnant G315.4-2.3 (RCW 86). The source is located 7&#39; to the Southwest of the geometrical centre and may be close to the actual explosion centre of the supernova, which makes this a candidate for the stellar remnant associated with RCW 86. However, the presence of a possible op

F. Combes

Although about a dozen high redshift (z larger than 2) starburst galaxies have been recently detected in the CO lines, spectroscopic detections of molecular gas of very young galaxies are still very difficult. The CO lines are usually optically thick, which limits greatly the increase of emission with redshift, as observed for the dust continuum. However the

D. W. Hoard, Paula Szkody, R. K. Honeycutt, Jeff Robertson

We present an analysis of ground-based optical photometry and spectroscopy, and Rossi X-ray Timing Explorer X-ray observations of the old novae DI Lacertae and V841 Ophiuchi. Our optical photometry data (obtained with the automated photometry telescope RoboScope) comprise an almost decade-long light curve for each star, while the contemporaneous spectroscopy

Eve C. Ostriker, James M. Stone, Charles F. Gammie

We use 3D numerical MHD simulations to follow the evolution of cold, turbulent, gaseous systems with parameters representing GMC conditions. We study three cloud simulations with varying mean magnetic fields, but identical initial velocity fields. We show that turbulent energy is reduced by a factor two after 0.4-0.8 flow crossing times (2-4 Myr), and that t

Eelco van Kampen

This paper discusses physical and numerical disruption processes acting on subhaloes in galaxy haloes and in galaxy cluster haloes, and compare the effects of these processes on the subhalo abundance within both types of haloes. N-body simulations with a resolution high enough not to suffer from overmerging (subhalo disruption due to numerical processes) sho

L. Morales-Rueda, T. R. Marsh, R. C. North

We present high resolution spectra of the AM CVn helium binary GP Com at two different wavelength ranges. The spectra show the same flaring behaviour observed in previous UV and optical data. We find that the central spike contributes to the flare spectra indicating that its origin is probably the compact object. We also detect that the central spike moves w

E. Ros, J. M. Marcaide, J. C. Guirado, M. A. Perez-Torres

We report on the present status of our S5 polar cap phase-connected astrometry program. We observe 13 radio sources in the northernmost 20deg of the sky at the wavelengths of 3.6cm and 2cm, and we plan to extend the program to 0.7cm. We phase-connect jointly all our data successfully. We image the radio sources and some of them show morphological changes, in

M. Feldt, M. Kasper, F. Eisenhauer, S. Hippler

In this paper, we discuss the benefits of ground-based, adaptive optics (AO) aided observations for star formation research. After outlining the general advantages, we present results obtained during the ALFA science demonstration programme in 1999. These results underline the absolute necessity of AO assistance for almost any kind of observations regarding

P. P. Avelino, C. J. A. P. Martins, G. Rocha, P. Viana

We perform a likelihood analysis of the recently released BOOMERanG and MAXIMA data, allowing for the possibility of a time-varying fine-structure constant. We find that in general this data prefers a value of $α$ that was smaller in the past (which is in agreement with measurements of $α$ from quasar observations). However, there are some interesting degene

S. Sheppard, D. Jewitt, C. Trujillo, M. Brown

A modified Baker-Nunn camera was used to conduct a wide-field survey of 1428 square degrees of sky near the ecliptic in search of bright Kuiper Belt objects and Centaurs. This area is an order of magnitude larger than any previously published CCD survey for Centaurs and Kuiper Belt Objects. No new objects brighter than red magnitude m=18.8 and moving at a ra

N. Langer, A. Deutschmann, S. Wellstein, P. Hoeflich

Close binaries consisting of a main sequence star and a white dwarf are considered as candidates for Type~Ia supernova progenitors. We present selfconsistent calculations of the time dependence of the structure of the main sequence star, the mass transfer rate, and the orbit by means of a binary stellar evolution program. In contrast to results based on simp

D. Pequignot, J. R. Walsh, A. A. Zijlstra, G. Dudziak

The planetary nebulae He 2-436 and Wray 16-423 in the Sagittarius dwarf galaxy appear to result from nearly twin stars, except that third-dredge-up carbon is more abundant in He 2-436. A thorough photoionization-model analysis implies that ratios Ne/O, S/O and Ar/O are significantly smaller in He 2-436, indicative of third-dredge-up oxygen enrichment. The en

A. P. Lobanov, L. I. Gurvits, S. Frey, R. T. Schilizzi

We report results of a VSOP (VLBI Space Observatory Programme) observation of a high redshift quasar PKS 2215+020 (z=3.572). The ~1 milliarcsecond resolution image of the quasar reveals a prominent `core-jet&#39; structure on linear scales from 5/h to 300/h pc ($H_0=100*h km/(s*Mpc). The brightness temperatures and sizes of bright features identified in the

Seungjoon Hyun

We show that the NCOS (noncommutative open string) theories on torus $T^p$ ($p\leq 5$) are U-dual to matrix theory on torus with electric flux background. Under U-duality, the number of D-branes and the number of units of electric flux get interchanged. Furthermore under the same U-duality the decoupling limit taken in the NCOS theory maps to the decoupling

Denis Dalidovich, Philip Phillips

We consider here the fluctuation conductivity near the point of the insulator-superconductor transition in a system of regular Josephson junction arrays in the presence of particle-hole asymmetry or equivalently homogeneous charge frustration. The transition is characterised by the dynamic critical exponent $z=2$, opening the possibility of the perturbative

C. J. Hemming, R. Kapral

The dynamics of spatiotemporal patterns in oscillatory reaction-diffusion systems subject to periodic forcing with a spatially random forcing amplitude field are investigated. Quenched disorder is studied using the resonantly forced complex Ginzburg-Landau equation in the 3:1 resonance regime. Front roughening and spontaneous nucleation of target patterns ar

B. J. Mochejska, J. Kaluzny, I. Thompson, W. Pych

We present UBV color magnitude diagrams (CMDs) for the globular cluster M4. The CMDs show a sequence of four luminous blue stars (V<20, U-V<-0.6) which appear to be cluster hot subdwarfs. We present spectra for the three brightest ones. We also note the presence of a population of faint blue objects, likely to be hot, young white dwarfs (WDs) belonging to th

Michael Gronau

We prove a general theorem about equal CP rate differences within pairs of U-spin related charmless $B$ and $B_s$ decays. Large deviations from equalities would be evidence for new physics. Six pairs of decays into two pseudoscalar mesons are identified where such relations hold. Ratios of corresponding rate differences and certain ratios of rates measure U-

W. Vincent Liu, Eduardo Fradkin

We study a model of the stripe state in strongly correlated systems consisting of an array of antiferromagnetic spin ladders, each with $n_{leg}$ legs, coupled to each other through the spin-exchange interaction to charged stripes in between each pair of ladders. The charged stripes are assumed to be Luttinger liquids in a spin-gap regime (Luther-Emery). An

A. C. Quillen, Mihoko Yukita

We measure reddenings to HII regions in NGC 2903, NGC 1512, M51, NGC 4449 and NGC 6946 from Hubble Space Telescope Pa alpha and H alpha images. Extinctions range from A_V ~ 5 - 0 depending upon the galaxy. For the galaxies with HST images in both lines, NGC 2903, NGC 1512 and M51, the Pa alpha and H alpha emission are almost identical in morphology which imp

N. Chamoun, S. J. Landau, H. Vucetich

We propose to generalize Bekenstein model for the time variation of the fine structure &#34;constant&#34; $α_{em}$ to QCD strong coupling constant $α_S$. We find that, except for a ``fine tuned&#39;&#39; choice of the free parameters, the extension can not be performed trivially without being in conflict with experimental constraints and this rules out $α_S$

H. -Th. Janka

Energy deposition by neutrinos can rejuvenate the stalled bounce shock and can provide the energy for the supernova explosion of a massive star. This neutrino-heating mechanism, however, is not finally accepted or proven as the trigger of the explosion. Part of the problem is that the complexity of the hydrodynamic models often hampers a clear and simple int

S. James Gates,, Hitoshi Nishino

At the component-level we study the `beta-function-favored constraint&#39; (bffc) formalism, suggested in 1988 as the most natural formulation for supergravity derived from more fundamental theories. We begin with the suggestion that \bffc supergravity be identified with new minimal supergravity together with an additional chiral compensator multiplet. After

Adel M. Awad, Clifford V. Johnson

Using the counterterm subtraction technique we calculatehe stress-energy tensor, action, and other physical quantities for Kerr-AdS black holes in various dimensions. For Kerr-AdS_5 with both rotation parameters non-zero, we demonstrate that stress-energy tensor, in the zero mass parameter limit, is equal to the stress tensor of the weakly coupled four dimen

A. L. Chernyshev, Y. C. Chen, A. H. Castro Neto

The problem of diluted two-dimensional (2D) quantum antiferromagnet (AF) on a square lattice is studied using spin-wave theory. The influence of impurities on static and dynamic properties is investigated and a good agreement with experiments and Monte Carlo (MC) data is found. The hydrodynamic description of spin-waves breaks down at characteristic waveleng

Thomas Kerler

We develop an explicit skein theoretical algorithm to compute the Alexander polynomial of a 3-manifold from a surgery presentation employing the methods used in the construction of quantum invariants of 3-manifolds. As a prerequisite we establish and prove a rather unexpected equivalence between the topological quantum field theory constructed by Frohman and

C. Ciuti, P. Schwendimann, A. Quattropani

The spectral and dispersive emission properties are analytically determined for the two-dimensional system of exciton-polaritons in microcavities excited by a resonant and coherent optical pump. New collective excitations result from the anomalous coupling between one generic polariton state and its idler, created by the scattering of two pumped polaritons.

Jakyoung Song, Sergio E. Ulloa

We study the effect of magnetic field and geometric confinement on excitons confined to a quantum ring. We use analytical matrix elements of the Coulomb interaction and diagonalize numerically the effective-mass Hamiltonian of the problem. To explore the role of different boundary conditions, we investigate the quantum ring structure with a parabolic confine

Antonio L. Maroto

We study the amplification of electromagnetic vacuum fluctuations induced by the evolution of scalar metric perturbations at the end of inflation. Such perturbations break the conformal invariance of Maxwell equations in Friedmann-Robertson-Walker backgrounds and allow the growth of magnetic fields on super-Hubble scales. We relate the strength of the fields

O. A. Castro-Alvaredo, A. Fring

The renormalization group flow of an integrable two dimensional quantum field theory which contains unstable particles is investigated. The analysis is carried out for the Virasoro central charge and the conformal dimensions as a function of the renormalization group flow parameter. This allows to identify the corresponding conformal field theories together

Dongsu Bak

We consider the noncommutative Abelian-Higgs theory and construct new types of exact multi-vortex solutions that solve the static equations of motion. They in general do not follow from the BPS equations; only for some specific values of parameters, they satisfy the BPS equations saturating the Bogomol&#39;nyi bound. We further consider the Abelian-Higgs the

T. Gehrmann, E. Remiddi

The calculation of the two-loop corrections to the three jet production rate and to event shapes in electron-positron annihilation requires the computation of a number of up to now unknown two-loop four-point master integrals with one off-shell and three on-shell legs. In this paper, we compute those master integrals which correspond to planar topologies by

Pedro Luis del Angel, Stefan Müller-Stach

We compute the transcendental part of the normal function corresponding to the Deligne class of a cycle in K_1 of a mirror family of quartic K3 surfaces. The resulting multivalued function does not satisfy the hypergeometric differential equation of the periods and we conclude that the cycle is indecomposable for most points in the mirror family. The occurri

J. M. Luck, Anita Mehta

We demonstrate via several examples that a uniform drift velocity gives rise to anomalous aging, characterized by a specific form for the two-time correlation functions, in a variety of statistical-mechanical systems far from equilibrium. Our first example concerns the oscillatory phase observed recently in a model of competitive learning. Further examples,

Miguel Alcubierre, Bernd Bruegmann

We describe a simple implementation of black hole excision in 3+1 numerical relativity. We apply this technique to a Schwarzschild black hole with octant symmetry in Eddington-Finkelstein coordinates and show how one can obtain accurate, long-term stable numerical evolutions.

Valery P. Dmitriyev

The formula for the electric field of a point charge moving with constant velocity is derived using the symmetry properties of Maxwell&#39;s equations - its Lorentz invariance. In contrast to conventional treatments, the derivation presented does not use retarded integrals or relativity transformations.

Fulvio Melia, Siming Liu, Robert Coker

The sub-mm bump observed in the spectrum of Sgr A* appears to indicate the existence of a compact emitting component within several Schwarzschild radii, $r_S$, of the nucleus at the Galactic Center. This is interesting in view of the predicted circularized flow within $\sim 5-10 r_S$, based on detailed multi-dimensional hydrodynamic simulations of Bondi-Hoyl

Kazuo Ghoroku

The renormalization group equations of the Yang-Mills theory are examined in the non-critical string theory according to the framework of the holography. Under a simple ansatz for the tachyon, we could find several interesting solutions which are classified by the value of the tachyon potential at the vacuum. We show two typical, asymptotic-free solutions wh

J. F. Corney, P. D. Drummond

The dynamics of a soliton propagating in a single-mode optical fiber with gain, loss, and Raman coupling to thermal phonons is analyzed. Using both soliton perturbation theory and exact numerical techniques, we predict that intrinsic thermal quantum noise from the phonon reservoirs is a larger source of jitter and other perturbations than the gain-related Go

P. D. Drummond, J. F. Corney

We analyze the quantum dynamics of radiation propagating in a single mode optical fiber with dispersion, nonlinearity, and Raman coupling to thermal phonons. We start from a fundamental Hamiltonian that includes the principal known nonlinear effects and quantum noise sources, including linear gain and loss. Both Markovian and frequency-dependent, non-Markovi

Rafael G. Campos, L. O. Pimentel, .

A useful finite-dimensional matrix representation of the derivative of periodic functions is obtained by using some elementary facts of trigonometric interpolation. This NxN matrix becomes a projection of the angular derivative into polynomial subspaces of finite dimension and it can be interpreted as a generator of discrete rotations associated to the z-com

Y. -T. Chough, H. J. Carmichael

It is problematic to interpret the quantum jumps of an atom interacting with thermal light in terms of counts at detectors monitoring the atom&#39;s inputs and outputs. As an alternative, we develop an interpretation based on a self-consistency argument. We include one mode of the thermal field in the system Hamiltonian and describe its interaction with the

J. Reichel, W. Hänsel, P. Hommelhoff, T. W. Hänsch

Lithographically fabricated circuit patterns can provide magnetic guides and microtraps for cold neutral atoms. By combining several such structures on the same ceramic substrate, we have realized the first ``atom chips&#39;&#39; that permit complex manipulations of ultracold trapped atoms or de Broglie wavepackets. We show how to design magnetic potentials

Mario Castagnino

A unified (classical-quantum-statistical) formalism for a system with continuous spectrum is introduced. For this kind of systems ergodicity behavior and the existence of microcanonical and canonical (KMS) equilibrium is proved. It is argued that the continuous spectrum condition is essential for the thermodynamical behavior

Miloslav Znojil

A few modified textbook Rayleigh-Schrödinger perturbative representations of bound states are reviewed. They were all inspired by an adaptive re-split of the Hamiltonian, using nonstandard bases and the flexibility of normalization of the wave functions.

Diana Duplij, Steven Duplij

Various symmetries connected with purine-pyrimidine content of DNA sequences are studied in terms of the intruduced determinative degree, a new characteristics of nucleotide which is connected with codon usage. A numerological explanation of CG pressure is proposed. A classification of DNA sequences is given. Calculations with real sequences show that purine

D. F. Phillips, M. A. Humphrey, E. M. Mattison, R. E. Stoner

We present a new measurement constraining Lorentz and CPT violation of the proton using a hydrogen maser double resonance technique. A search for hydrogen Zeeman frequency variations with a period of the sidereal day (23.93 h) sets a clean limit on violation of Lorentz and CPT symmetry of the proton at the 10^{-27} GeV level.

J. Reignier

Special relativity was discovered at the eve of the century, but finds its roots in the 19th century efforts to understand the optics and electromagnetism of moving bodies. These roots are reviewed in Parts 1 and 2, the latter being specially devoted to the works of Lorentz and of Poincare up to 1904. Part 3 contains a detailed comparison of the works of Ein

Kirk T. McDonald

A wheel or sphere rolling without slipping on the inside of a sphere in a uniform gravitational field can have stable circular orbits that lie wholly above the &#34;equator&#34;, while a particle sliding freely cannot.

K. L. F. Bane, V. V. Stupakov

In accelerator projects involving the use of very short bunches, such as the Linac Coherent Light Source (LCLS)-where the rms bunch length in the undulator section is 30 micron-, it appears that even submicron imperfections in the beam tube surface can generate an impedance that is unacceptably large. We consider two periodic models of an imperfect, rough su

H. Leeb, S. A. Sofianos, J. -M. Sparenberg, D. Baye

A transformation of supersymmetric quantum mechanics for N coupled channels is presented, which allows the introduction of up to N degenerate bound states without altering the remaining spectrum of the Hamiltonian. Phase equivalence of the Hamiltonian can be restored by two successive supersymmetric transformations at the same energy. The method is successfu

M. Guttormsen, M. Hjorth-Jensen, E. Melby, J. Rekstad

Information on level density for nuclei with mass numbers A = 20 - 250 is deduced from discrete low-lying levels and neutron resonance data. The odd-mass nuclei exhibit in general 4 - 7 times the level density found for its neighboring even-even nuclei at the same excitation energy. This excess corresponds to an entropy of approx. 1.7 k for the odd particle.

Ph. Feinsilver, M. Giering, J. Kocik

The approach of Berezin to the quantization of so(n,2) via generalized coherent states is considered in detail. A family of n commuting observables is found in which the basis for an associated Fock-type representation space is expressed. An interesting feature is that computations can be done by explicit matrix calculations in a particular basis. The basic

A. Chodos, G. Gallatin

Standard discussions of Goldstone&#39;s theorem based on a symmetry of the action assume constant fields and global transformations, i.e., transformations which are independent of spacetime coordinates. By allowing for arbitrary field distributions in a general representation of the symmetry we derive a generalization of the standard Goldstone&#39;s theorem.

Lenhard L. Ng

We resolve a question of Fuchs and Tabachnikov by showing that there is a Legendrian knot in standard contact three-space with zero Maslov number which is not Legendrian isotopic to its mirror. The proof uses the differential graded algebras of Chekanov.

Andrei Khruzin

We determine the number of nonequivalent chord diagrams of order $n$ under the action of two groups, $C_{2n}$, a cyclic group of order $2n$, and $D_{2n}$, a dihedral group of order $4n$. Asymptotic formulas are also established.

Nils Berglund, Barbara Gentz

The slow drift (with speed $\eps$) of a parameter through a pitchfork bifurcation point, known as the dynamic pitchfork bifurcation, is characterized by a significant delay of the transition from the unstable to the stable state. We describe the effect of an additive noise, of intensity $σ$, by giving precise estimates on the behaviour of the individual path

Guenther Hoermann, Michael Kunzinger

The Colombeau algebra of generalized functions allows to unrestrictedly carry out products of distributions. We analyze this operation from a microlocal point of view, deriving a general inclusion relation for wave front sets of products in the algebra. Furthermore, we give explicit examples showing that the given result is optimal, i.e. its assumptions cann

A. Beauville

We prove that a smooth hypersurface of degree >2 and dimension >1 admits no endomorphism of degree >1 (for hyperquadrics this is due to Paranjape and Srinivas). We then collect some general results on endomorphisms of projective manifolds; we prove in particular that ramified endomorphisms occur only on varieties of negative Kodaira dimension, and we classif

J. G. Russo

These are introductory lectures on the correspondence between SU(N) gauge theories and Superstring Theory in anti-de Sitter geometries (AdS). The subject combines a number of different topics, including supersymmetric field theory, classical and quantum physics of black holes, string theory, string dualities, conformal field theories (CFT), and quantum field