October 1999 arXiv papers — page 20

V. A. Rubakov

We comment on two issues in quantum cosmology, in the context of the Wheeler-De Witt equation and wave function of the Universe: (i) arrow of time and interpretation of the wave function in the classically allowed regions; (ii) stability of an approximation of the Born-Oppenheimer type in classically forbidden regions of the scale factor.

Z. A. Xu, N. P. Ong, T. Noda, H. Eisaki

The Nd-doped cuprate La_{2-y-x}Nd_ySr_xCuO_4 displays a first-order phase transition at T_d (= 74 K for x=0.10, y = 0.60) to a low-temperature tetragonal (LTT) phase. A magnetic field H applied || the a-axis leads to an increase in T_d, whereas T_d is decreased when H || c. These effects show that magnetic ordering involving both Nd and Cu spins plays a key

Nic Shannon

We prove a simple theorem on the overlap of the wavefunctions of a manybody system with and without a single impurity and show how, and under which conditions, this leads to the ``Orthogonality Catastrophe'' (OC) described by Anderson. A compact new derivation of the known result for the OC exponent in a free electron gas, $α=2 \sum_l(2l+1) (δ_l(ε_f)

A. Marchenkov, R. W. Simmonds, A. Loshak, J. C. Davis

The quantum phase difference across a superfluid Josephson-like weak link may exhibit periodic motion describable by a nonlinear equation identical to that of a rigid pendulum. We have directly observed this mode and find that the phase oscillation frequency decreases toward zero as the phase amplitude increases toward $π$. We also find that the low amplitud

H. Feldmann, R. Oppermann

The fermionic Ising spin glass is analyzed for arbitrary filling and for all temperatures. A selforganized 3-band structure of the model is obtained in the magnetically ordered phase. Deviation from half filling generates a central nonmagnetic band, which becomes sharply separated at T=0 by (pseudo)gaps from upper and lower magnetic bands. Replica symmetry b

W. A. C. Passos, F. M. Araujo-Moreira, W. A. Ortiz

In this work we study the magnetic remanence exhibited by Josephson junction arrays in response to an excitation with an AC magnetic field. The effect, predicted by numerical simulations to occur in a range of temperatures, is clearly seen in our tridimensional disordered arrays. We also discuss the influence of the critical current distribution on the tempe

S. Ilani, A. Yacoby, D. Mahalu, Hadas Shtrikman

We have measured the local electronic compressibility of a two-dimensional hole gas as it crosses the B=0 Metal-Insulator Transition. In the metallic phase, the compressibility follows the mean-field Hartree-Fock (HF) theory and is found to be spatially homogeneous. In the insulating phase it deviates by more than an order of magnitude from the HF prediction

Jonathan Doye

In this paper I describe the computer simulations that I have performed to critically examine the Lauritzen-Hoffman and the Sadler-Gilmer theories of polymer crystallization. In particular, I have computed the free energy profile for nucleation of a new crystalline layer on the growth face to compare with that assumed by the Lauritzen-Hoffman theory, I have

V. A. Schweigert, F. M. Peeters

Using a linear analysis, we study the stability of giant-vortex states in very thin disks. The vortex expulsion and penetration fields are obtained for finite thickness disks from a numerical solution of the non-linear Ginzburg-Landau (GL) equations. Using an extension of the London approximation, in which the phase distribution of the order parameter is pre

Vittorio Basso, Cinzia Beatrice, Martino LoBue, Paola Tiberto

The connection between hysteresis and thermal relaxation in magnetic materials is studied from both the experimental and the theoretical viewpoint. Hysteresis and viscosity effects are measured in Finemet-type nanocrystalline materials above the Curie temperature of the amorphous phase, where the system consists of ferromagnetic nanograins imbedded in a para

G. Khaliullin, R. Kilian

In metallic manganites with low Curie temperatures, a peculiar softening of the magnon spectrum close to the magnetic zone boundary has experimentally been observed. Here we present a theory of the renormalization of the magnetic excitation spectrum in colossal magnetoresistance compounds. The theory is based on the modulation of magnetic exchange bonds by t

Guido Burkard, Georg Seelig, Daniel Loss

We determine the spin exchange coupling J between two electrons located in two vertically tunnel-coupled quantum dots, and its variation when magnetic (B) and electric (E) fields (both in-plane and perpendicular) are applied. We predict a strong decrease of J as the in-plane B field is increased, mainly due to orbital compression. Combined with the Zeeman sp

A. Langari, M. Abolfath, M. A. Martin-Delgado

We study the phase diagram of a 2-leg bond-alternation spin-(1/2, 1) ladder for two different configurations using a quantum renormalization group approach. Although d-dimensional ferrimagnets show gapless behavior, we will explicitly show that the effect of the spin mixing and the bond-alternation can open the possibility for observing an energy gap. We sho

J. C. Flores, E. Lazo

We study the effect of charge discreteness in a quantum mesoscopic ring wih inductance L. The ring is pierced by a time depending external magnetic field. When the external magnetic flux varies uniformly, the current induced in the ring oscillates with a frequency proportional to the charge discreteness and the flux variation. This phenomenon is very similar

R. P. van Gorkom, Arne Brataas, Gerrit E. W. Bauer

The electrical resistance of a diffusive ferromagnet with magnetic domain walls is studied theoretically, taking into account the spatial dependence of the magnetization. The semiclassical domain wall resistance is found to be either negative or positive depending on the difference between the spin-dependent scattering life-times. The predictions can be test

Adam Lipowski

Using Monte Carlo simulations we study a lattice model of a prey-predator system. We show that in the three-dimensional model populations of preys and predators exhibit coherent periodic oscillations but such a behaviour is absent in lower-dimensional models. Finite-size analysis indicate that amplitude of these oscillations is finite even in the thermodynam

C. Schindelin, D. Ihle, S. -L. Drechsler, H. Fehske

The ground-state properties of the square-lattice spin-1/2 Heisenberg antiferromagnet with spatially anisotropic couplings are investigated by Green's-function projection approaches. The staggered magnetization and the two-spin correlators are calculated; the competition between magnetic long- and short-range order is discussed in comparison with experim

H. Fehske, G. Wellein, H. Büttner, A. R. Bishop

We analyze numerically the ground-state and spectral properties of the three-quarter filled Peierls-Hubbard Hamiltonian. Various charge- and spin-ordered states are identified. In the strong-coupling regime, we find clear signatures of local lattice distortions accompanied by intrinsic multi-phonon localization. The results are discussed in relation to recen

D. Mentrup, H. -J. Schmidt, J. Schnack, Marshall Luban

We focus on the transition from quantum to classical behavior in thermodynamic functions and time correlation functions of a system consisting of three identical quantum spins s that interact via isotropic Heisenberg exchange. The partition function and the zero-field magnetic susceptibility are readily shown to adopt their classical forms with increasing s.

A. V. Chechkin, V. Yu. Gonchar

We get fractional symmetric Fokker - Planck and Einstein - Smoluchowski kinetic equations, which describe evolution of the systems influenced by stochastic forces distributed with stable probability laws. These equations generalize known kinetic equations of the Brownian motion theory and contain symmetric fractional derivatives over velocity and space, resp

Andrey V. Chubukov, Nathan Gemelke, Ar. Abanov

We study $B_{1g}$ Raman intensity $R(Ω)$ and the density of states $N(ω)$ in isotropic 2D d-wave superconductors. For an ideal gas, $R(Ω)$ and $N(ω)$ have sharp peaks at $Ω=2Δ$ and $ω=Δ$, respectively, where $Δ$ is the maximum value of the gap. We study how the peak positions are affected by the fermionic damping due to impurity scattering. We show that whil

Paolo Padoan, ; Ellen Zweibel, ; AAke Nordlund

Although thermal pressure is unimportant dynamically in most molecular gas, the temperature is an important diagnostic of dynamical processes and physical conditions. This is the first of two papers on thermal equilibrium in molecular clouds. We present calculations of frictional heating by ion-neutral (or ambipolar) drift in three-dimensional simulations of

Sidney van den Bergh

The mass M, and the radius R_h, of the Centaurus A group are estimated from the positions and radial velocities of 30 probable cluster members. For an assumed distance of 3.9 Mpc it is found that R_h \sim 640 kpc. The velocity dispersion in the Cen A group is 114 \pm 21 km/s. From this value, and R_h = 640 kpc, the virial theorem yields a total mass of 1.4 \

Marcelo B. Ribeiro

The two-point correlation function for the dust distribution in the unperturbed Einstein-de Sitter cosmological model is studied along the past light cone. It was found that this function seems unable to represent the theoretical distribution of dust along the backward null cone of this unperturbed model, which has already been determined in a previous paper

C. C. Steidel, K. L. Adelberger, A. E. Shapley, M. Pettini

We present very deep imaging observations, through a narrow-band filter tuned to Lyman alpha at <z = 3.09>, of a volume containing a significant over-density of galaxies at this redshift previously discovered in our survey for continuum-selected Lyman break galaxies (LBGs). The new observations are used in conjunction with our spectroscopic results on LBGs t

N. Neininger

We are performing a fully sampled survey of the 12CO(1-0) line emission of the nearby galaxy M 31 with the IRAM 30-m telescope. The resolution obtained is 23&#34; which corresponds to about 90 pc along the major axis. This small beam is well adapted to the size of typical structures of the molecular gas and allows to detect even interarm cloud complexes. We

A. D&#39;Ercole, S. Recchi, L. Ciotti

During a Hubble time, cluster galaxies may undergo several mutual encounters close enough to gravitationally perturb their hot, X-ray emitting gas flows. We ran several 2D, time dependent hydrodynamical models to investigate the effects of such perturbations on the gas flow inside elliptical galaxies. In particular, we studied in detail the modifications occ

D. M. Worrall, M. Birkinshaw

We report ROSAT PSPC spatial and spectral analysis of the eight B2 radio galaxies NGC 315, NGC 326, 4C 35.03, B2 0326+39, NGC 2484, B2 1040+31, B2 1855+37, and 3C 449, expected to be representative of the class of low-power radio galaxies. Multiple X-ray components are present in each, and the gas components have a wide range of linear sizes and follow an ex

A. Georgakakis, B. Mobasher, L. Cram, A. Hopkins

The significance of tidal interactions in the evolution of the faint radio population (sub-mJy) is studied using a deep and homogeneous radio survey (1.4 GHz), covering an area of 3.14 deg$^2$ and complete to a flux density of 0.4 mJy. Optical photometric and spectroscopic data are also available for this sample. A statistical approach is employed to identif

P. Reig, M. Mendez, M. van der Klis, E. Ford

Based on Rossi X-ray Timing Explorer data, we discuss the classification of the soft X-ray transient Aquila X-1 in the Z/atoll scheme, and the relation of its kilohertz quasi-periodic oscillations (kHz QPO) properties to the X-ray colors. The color-color diagram shows one elongated (&#34;banana&#34;) structure and several &#34;islands&#34; of data points. Th

C. R. Contaldi, P. G. Ferreira, J. Magueijo, K. M. Gorski

We propose a formalism for estimating the skewness and angular power spectrum of a general Cosmic Microwave Background data set. We use the Edgeworth Expansion to define a non-Gaussian likelihood function that takes into account the anisotropic nature of the noise and the incompleteness of the sky coverage. The formalism is then applied to estimate the skewn

René A. Méndez, Imants Platais, Terrence M. Girard, Vera Kozhurina-Platais

The predictions from a Galactic Structure and Kinematic model code are compared to the color counts and absolute proper-motions derived from the Southern Proper-Motion survey covering more than 700 $°^2$ toward the South Galactic Pole in the range $9 < B_{\rm J} \le 19$. The theoretical assumptions and associated computational procedures, the geometry for th

I. Karachentsev, A. Aparicio, L. Makarova

The distance, star formation history and global properties of the Local Group dIrr galaxy SagDIG are derived based on an [I-(V-I)] colour--magnitude diagram of ~1550 stars. A distance of 1.06+/-0.10 Mpc is obtained from the I magnitude of the TRGB. This corresponds to 1.17 Mpc to the barycenter of the Local Group and 1.34 to M 31, being DDO 210, at 0.35 Mpc,

V. N. Lukash, E. V. Mikheeva

We explore a broad class of three-parameter inflationary models, called the $Λ$-inflation, and its observational predictions: high abundance of cosmic gravitational waves consistent with the Harrison-Zel&#39;dovich spectrum of primordial cosmological perturbations, the non-power-law wing-like spectrum of matter density perturbations, high efficiency of these

A. Kinkhabwala, S. E. Thorsett

Giant pulses are short, intense outbursts of radio emission with a power-law intensity distribution that have been observed from the Crab Pulsar and PSR B1937+21. We have undertaken a systematic study of giant pulses from PSR B1937+21 using the Arecibo telescope at 430, 1420, and 2380 MHz. At 430 MHz, interstellar scattering broadens giant pulses to duration

BAIKAL Collaboration, V. Balkanov

We present the results of a search for high energy neutrinos with the Baikal underwater Cherenkov detector NT-96. An upper limit to the flux of ν_e + ν_μ + \bar{ν_μ} of E^2F_ν(E)<1.4 10^{-5} cm^{-2} s^{-1} sr^{-1} GeV is obtained, assuming an E^{-2} behavior of the neutrino spectrum.

Edwin A. Bergin

We discuss recent models of chemical evolution in the developing and collapsing protostellar envelopes associated with low-mass star formation. In particular, the effects of depletion of gas-phase molecules onto grain surfaces is considered. We show that during the middle to late evolutionary stages, prior to the formation of a protostar, various species sel

Max Pettini, Sara Ellison, Charles C. Steidel, Alice E. Shapley

We have measured the abundances of Zn, Si, Mn, Cr, Fe, and Ni in three damped Lyman alpha systems at redshifts z < 1 from high resolution echelle spectra of QSOs recorded with the Keck I telescope. In all three cases the abundances of Cr, Fe, and Ni relative to Zn indicate low levels of dust depletions. We propose that when the proportion of refractory eleme

R. Fux

A high-resolution N-body simulation suggests that stellar streams in the discs of barred galaxies are common and strongly time-dependent. The velocity distribution of stars in the Solar neighbourhood betray many such streams, including a stream of outward moving stars with low angular momentum. This stream is interpreted as a signature of the Galactic bar, i

E. Rizza, C. Loken, M. Bliton, K. Roettiger

We present high resolution ROSAT x-ray and radio observations of three cooling flow clusters containing steep spectrum radio sources at their cores. All three systems exhibit strong signs of interaction between the radio plasma and the hot intracluster medium. Two clusters, A133 and A2626, show enhanced x-ray emission spatially coincident with the radio sour

Matthew G. Baring

Most recent extragalactic models of gamma-ray bursts consider the expansion of a relativistic blast wave, emanating from a solar-mass type progenitor, into the surrounding interstellar medium as the site for their activity. The popular perception is that the optical afterglows result from the external shock interface, while the prompt transient gamma-ray sig

Matthew G. Baring, Alice K. Harding

Developments over the last couple of years have supported the interpretation that anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) possess unusually high magnetic fields, and furthermore may represent a class or classes of neutron stars distinct from the population of conventional radio pulsars. We have recently suggested that such a dichotomiz

Frank C. Jones, Matthew G. Baring, Donald C. Ellison

We have modeled the injection and acceleration of pickup ions at the solar wind termination shock and investigated the parameters needed to produce the observed Anomalous Cosmic Ray (ACR) fluxes. A non-linear Monte Carlo technique was employed which in effect solves the Boltzmann equation and is not restricted to near isotropic particle distribution function

Donald C. Ellison, Philippe Goret, Matthew G. Baring, Isabelle A. Grenier

We calculate particle spectra and continuum photon emission from the Cassiopeia A supernova remnant (SNR). The particle spectra, ion and electron, result from diffusive shock acceleration at the forward SNR shock and are determined with a nonlinear Monte Carlo calculation. The calculation self-consistently determines the shock structure under the influence o

A. B. Giles, K. M. Hill, J. G. Greenhill

A set of CCD images have been obtained during the decline of the X-ray transient SAX J1808.4-3658 during April-June 1998. The optical counterpart has been confirmed by several pieces of evidence. The optical flux shows a modulation on several nights which is consistent with the established X-ray binary orbit period of 2 hours. This optical variability is rou

Iosif Bena

In this brief note we construct the propagator for the antisymmetric tensor in AdS_{d+1}. We check our result using the Poincare duality between the antisymmetric tensor and the gauge boson in AdS_5. This propagator was needed for a computation which turned out to be too hard. It can be used for computing various other things in AdS.

Tim R. Morris

A manifestly gauge invariant continuous renormalization group flow equation is constructed for pure SU(N) gauge theory. The formulation makes sense without gauge fixing and manifestly gauge invariant calculations may thus be carried out. The flow equation is naturally expressed in terms of fluctuating Wilson loops, with the effective action appearing as an i

Michael B. Green, Pierre Vanhove

The one-loop four-graviton amplitude in either of the type II superstring theories is expanded in powers of the external momenta up to and including terms of order s^4 log s R^4, where R^4 denotes a specific contraction of four linearized Weyl tensors and s is a Mandelstam invariant. Terms in this series are obtained by integrating powers of the two-dimensio

In-Sang Yang, M. V. Klein, S. L. Cooper, P. C. Canfield

Superconductivity-induced changes in the electronic Raman scattering response were observed for the RNi$_2$B$_2$C (R = Y, Lu) system in different scattering geometries. In the superconducting state, 2$Δ$-like peaks were observed in A$_{1g}$, B$_{1g}$, and B$_{2g}$ spectra from single crystals. The peaks in A$_{1g}$ and B$_{2g}$ symmetries are significantly s

Michael B. Green, Hwang-h. Kwon, Pierre Vanhove

The two-loop Feynman diagram contribution to the four-graviton amplitude of eleven-dimensional supergravity compactified on a two-torus, T^2, is analyzed in detail. The Schwinger parameter integrations are re-expressed as integration over the moduli space of a second torus, \hat T^2, which enables the leading low-momentum contribution to be evaluated in term

B. Noheda, J. A. Gonzalo, L. E. Cross, R. Guo

The perovskite-like ferroelectric system PbZr(1-x)Ti(x)O3 (PZT) has a nearly vertical morphotropic phase boundary (MPB) around x=0.45-0.50. Recent synchrotron x-ray powder diffraction measurements by Noheda et al. [Appl. Phys. Lett. 74, 2059 (1999)] have revealed a new monoclinic phase between the previously-established tetragonal and rhombohedral regions. I

R. C. Myers

We extend the usual world-volume action for a Dp-brane to the case of N coincident Dp-branes where the world-volume theory involves a U(N) gauge theory. The guiding principle in our construction is that the action should be consistent with the familiar rules of T-duality. The resulting action involves a variety of potential terms, i.e., nonderivative interac

Tamas Hauer, Amer Iqbal

A map between string junctions in the affine 7-brane backgrounds and vector bundles on del Pezzo surfaces is constructed using mirror symmetry. It is shown that the lattice of string junctions with support on an affine 7-brane configuration is isomorphic to the K-theory group of the corresponding del Pezzo surface. This isomorphism allows us to construct a m

M. Alford, J. Berges, K. Rajagopal

We discuss the Meissner effect for a color superconductor formed by cold dense quark matter. Though color and ordinary electromagnetism are broken in a color superconductor, there is a linear combination of the photon and a gluon that remains massless. Consequently, a color superconducting region may be penetrated by an external magnetic field. We show that

L. Henderson, L. Hardy, V. Vedral

Quantum teleportation with additional a priori information about the input state achieves higher fidelity than teleportation of a completely unknown state. However, perfect teleportation of two non-orthogonal input states requires the same amount of entanglement as perfect teleportation of an unknown state, namely one ebit. We analyse how well two-state tele

H. Umeda, K. Nomoto, S. Tsuruta, S. Mineshige

Very recently the Chandra First Light Observation discovered a point-like source in Cassiopeia A (Cas A) supernova remnant. This detection was subsequently confirmed by the analyses of the archival data from both ROSAT and Einstein observations. Here we compare the results from these observations with the scenarios involving both black holes (BH) and neutron

Sergio Caracciolo, Maria Serena Causo, Andrea Pelissetto

We study the end-to-end distribution function for dilute polymers. We present a computation to order $O(ε^2)$, $ε= 4 - d$, and discuss in detail its asymptotic behaviour for small and large distances. The theoretical predictions are compared with Monte Carlo results, finding good agreement.

David P. DiVincenzo, Peter W. Shor, John A. Smolin, Barbara M. Terhal

We exhibit a two-parameter family of bipartite mixed states $ρ_{bc}$, in a $d\otimes d$ Hilbert space, which are negative under partial transposition (NPT), but for which we conjecture that no maximally entangled pure states in $2\otimes 2$ can be distilled by local quantum operations and classical communication (LQ+CC). Evidence for this undistillability is

A. W. Holleitner, H. Qin, F. Simmel, B. Irmer

We present measurements on microwave spectroscopy on a double quantum dot with an on-chip microwave source. The quantum dots are realized in the two-dimensional electron gas of an AlGaAs/GaAs heterostructure and are weakly coupled in series by a tunnelling barrier forming an &#39;ionic&#39; molecular state. We employ a Josephson oscillator formed by a long N

Enzo Granato

Vortex critical dynamics of the two dimensional XY spin glass is studied by Monte Carlo methods in the Coulomb-gas representation. A scaling analysis of the nonlinear response is used to calculate the correlation length exponent $ν$ of the zero-temperature glass transition. The estimate, $ν=1.3(2)$, is in agreement witth a recent estimate in the phase repres

J. R. Forshaw, G. R. Kerley, G. Shaw

We employ a parameterisation of the proton dipole cross section previously extracted from electroproduction and photoproduction data to predict the diffractive structure function F2D(3)(Q^2, beta, xpom). Comparison with HERA H1 data yields good agreement.

A. Chuvakin, J. Smith, W. L. van Neerven

Where appropriate, the abbreviation &#39;VFNS&#39; is replaced by &#39;CSN&#39; to indicate the scheme using massive heavy quark coefficient functions proposed in this paper. The text below Eq. (2.13) and between Eqs. (2.33) and (2.36) has been considerably changed.

Satoshi Fujimoto

We study the strong correlation effects in the vicinity of the Mott metal-insulator transition using coupled clean or disordered Hubbard chains with a infinitely large coordinate number $D_{\perp}\to\infty$ in the direction perpendicular to the chains and with a long-range transverse hopping. Strong electron correlation effects are treated partially non-pert

E. P. Nakhmedov, H. Feldmann, R. Oppermann

A new diagrammatic method, which is a reformulation of Berezinskii&#39;s technique, is constructed to study the density of electronic states $ρ(ε,ϕ)$ of a one-channel weakly disordered ring, threaded by an external magnetic flux. The exact result obtained for the density of states shows an oscillation of $ρ(ε,ϕ)$ with a period of the flux quantum $ϕ_0= hc/e

S. Pakvasa

I review explanations for the three neutrino anomalies (solar, atmospheric and LSND) which go beyond the ``conventional&#39;&#39; neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well.

Diego A. R. Dalvit, Paulo A. Maia Neto

We derive a master equation for a mirror interacting with the vacuum field via radiation pressure. The dynamical Casimir effect leads to decoherence of a &#39;Schroedinger cat&#39; state in a time scale that depends on the degree of &#39;macroscopicity&#39; of the state components, and which may be much shorter than the relaxation time scale. Coherent states

Kentaro Imafuku, Kazuya Yuasa, Ichiro Ohba

After a brief review of stochastic limit approximation with spin-boson system from physical points of view, amplification phenomenon-stochastic resonance phenomenon-in driven spin-boson system is observed which is helped by the quantum white noise introduced through the stochastic limit approximation. The shift in frequency of the system due to the interacti

B. T. H. Varcoe, R. Sang, W. R. MacGillivray, M. C. Standage

We present a novel technique in which the total internal quantum state of an atom may be reconstructed via the measurement of the momentum transferred to an atom following its interaction with a near resonant travelling wave laser beam. We present the first such measurement and demonstrate the feasibility of the technique.

W. Dür, J. I. Cirac, M. Lewenstein, D. Bruss

We study the distillability of a certain class of bipartite density operators which can be obtained via depolarization starting from an arbitrary one. Our results suggest that non-positivity of the partial transpose of a density operator is not a sufficient condition for distillability, when the dimension of both subsystems is higher than two.

Wan-Li Li, Chuan-Feng Li, Guang-Can Guo

Teleportation may be taken as sending and extracting quantum information through quantum channels. In this report, it is shown that to get the maximal probability of exact teleportation through partially entangled quantum channels, the sender (Alice) need only to operate a measurement which satisfy an ``entanglement matching&#39;&#39; to this channel. An opt

G. F. Gribakin, V. K. Ivanov, A . V. Korol, M . Yu. Kuchiev

Absolute three-photon detachment cross sections are calculated for the fluorine negative ion within the lowest-order perturbation theory. The Dyson equation of the atomic many-body theory is used to obtain the ground-state 2p wavefunction with correct asymptotic behaviour, corresponding to the true (experimental) binding energy. We show that in accordance wi

G. N. Afanasiev, V. G. Kartavenko

The effects arising from accelerated and decelerated motion of a point charge inside a medium are studied. The motion is manifestly relativistic and may be produced by a constant uniform electric field. It is shown that in addition to the bremsstrahlung and Cherenkov shock waves, the electromagnetic shock wave arises when the charge particle velocity coincid

W. Florkowski, W. Broniowski

We confront the hypothesis of chemical freeze-out in ultra-relativistic heavy-ion collisions with the hypothesis of large modifications of hadron masses in nuclear medium. We find that the thermal-model predictions for the ratios of particle multiplicities are sensitive to the values of in-medium hadronic masses. In particular, the $π^+/p$ ratio decreases by

Joseph P. Previte, Eugene Z. Xia

Let M be a Riemann surface with boundary $\partial M$ and genus greater than zero. Let $Γ$ be the mapping class group of M fixing $\partial M$. The group $Γ$ acts on ${\mathcal M}_{\mathcal C} = \Hom_{\mathcal C}(π_1(M),SU(2)/SU(2)$ which is the space of SU(2)-gauge equivalence classes of flat SU(2)-connections on M with fixed holonomy on $\partial M$. We st

K. R. Goodearl, T. H. Lenagan, L. Rigal

We prove First Fundamental Theorems of Coinvariant Theory for the standard coactions of the quantum general and special linear groups on tensor products of quantum matrix algebras. More precisely, let m,n,t be arbitrary positive integers, let A and B be the quantum coordinate rings of the $t \times t$ general and special linear groups over an arbitrary field

Andras Vasy

We describe the propagation of singularities of tempered distributional generalized eigenfunctions of many-body Hamiltonians at non-threshold energies under the assumption that the inter-particle interactions are real-valued polyhomogeneous symbols of order -1 (e.g. Coulomb-type, but without the singularity at the origin). Here the term `singularity&#39; ref

Marco Abate

We describe a canonical procedure for associating to any (germ of) holomorphic self-map f of C^n fixing the origin such that df_O is invertible and non-diagonalizable an n-dimensional complex manifold M, a holomorphic map p from M to C^n, a point e in M and a (germ of) holomorphic self-map F of M so that: p restricted to the complement of p^{-1}(O) is a biho

D. Calow, R. Matthes

Extending work of Budzynski and Kondracki, we investigate coverings and gluings of algebras and differential algebras. We describe in detail the gluing of two quantum discs along their classical subspace, giving a C*-algebra isomorphic to a certain Podles sphere, as well as the gluing of U_{\sqrt{q}}(sl_2)-covariant differential calculi on the discs.

J. F. Feinstein, E. Kaniuth, D. W. B. Somerset

This paper continues the study of spectral synthesis and the topologies $τ_{\infty}$ and $τ_r$ on the ideal space of a Banach algebra, concentrating on the class of Banach $^*$-algebras, and in particular on $L^1$-group algebras. It is shown that if a group G is a finite extension of an abelian group then $τ_r$ is Hausdorff on the ideal space of $L^1(G)$ if

Zinovy Reichstein, Boris Youssin, János Kollár, Endre Szabó

Let G be an algebraic group and let X be a generically free G-variety. We show that X can be transformed, by a sequence of blowups with smooth G-equivariant centers, into a G-variety X&#39; with the following property: the stabilizer of every point of X&#39; is isomorphic to a semidirect product of a unipotent group U and a diagonalizable group A. As an appl

Scott Crass

The requirement for solving a polynomial is a means of breaking its symmetry, which in the case of the quintic, is that of the symmetric group S_5. Induced by its five-dimensional linear permutation representation is a three-dimensional projective action. A mapping of complex projective 3-space with this S_5 symmetry can provide the requisite symmetry-breaki

Washington Taylor, Mark Van Raamsdonk

We find the terms in the nonabelian world-volume action of a system of many Dp-branes which describe the leading coupling to all type II supergravity background fields. These results are found by T-dualizing earlier results for D0-branes, which in turn were determined from calculations of the M(atrix) theory description of the supercurrent of 11D supergravit

R. Acharya

It is shown that quantum chromodynamics based on asymptotic freedom and confinement exhibits the vector mode of chiral symmetry conjectured by Georgi.

G. Gabadadze, M. Shifman

A number of arguments exists that the &#34;minimal&#34; BPS wall width in large N supersymmetric gluodynamics vanishes as 1/N. There is a certain tension between this assertion and the fact that the mesons coupled to the gluino condensate have masses which do not scale with N. To reconcile these facts we argue that there should exist additional soliton-like

J. A. Nieto

We develope the analogue of S-duality for linearized gravity in (3+1)-dimensions. Our basic idea is to consider the self-dual (anti-self-dual) curvature tensor for linearized gravity in the context of the Macdowell-Mansouri formalism. We find that the strong-weak coupling duality for linearized gravity is an exact symmetry and implies small-large duality for

Jussi Kalkkinen

As superstring solitons that carry Neuveu-Schwarz charge can be described in terms of gerbes, one expects non-Abelian gerbes to appear e.g. in the exotic six-dimensional world-volume theories of coinciding NS5 branes. We consider open bosonic strings on a space-time that is branched in such a way that the B-field is provided with the same Lie algebra structu

Katsushi Ito

We study the hybrid formulation of Green-Schwarz superstrings on AdS_3 with NS flux and the boundary N=4 superconformal algebra. We show the equivalence between the NSR and GS superstrings by a field redefinition. The boundary N=4 superconformal algebra is realized by the free fields of the affine Lie superalgebra A(1|1)^{(1)}. We also consider the light-con

J. Balog, L. Feher, L. Palla

The chiral WZNW symplectic form $Ω^ρ_{chir}$ is inverted in the general case. Thereby a precise relationship between the arbitrary monodromy dependent 2-form appearing in $Ω^ρ_{chir}$ and the exchange r-matrix that governs the Poisson brackets of the group valued chiral fields is established. The exchange r-matrices are shown to satisfy a new dynamical gener

Alexander Burinskii

The structure of spinning particle suggested by the rotating Kerr-Newman (black hole) solution, super-Kerr-Newman solution and the Kerr-Sen solution to low energy string theory is considered. Main peculiarities of the Kerr spinning particle are discussed: a vortex of twisting principal null congruence, singular ring and the Kerr source representing a rotatin

M. Yu. Kuchiev

Conventional non-Abelian SO(4) gauge theory is able to describe gravity provided the gauge field possesses a specific polarized vacuum state in which the instantons have a preferred orientation. Their orientation plays the role of the order parameter for the polarized phase of the gauge field. The interaction of a weak and smooth gauge field with the polariz

Davoud Kamani

In this article we present a general description of two moving branes in presence of the $B_{μν}$ field and gauge fields $A^{(1)}_{α_1}$ and $A^{(2)}_{α_2}$ on them, in spacetime in which some of its directions are compact on tori. Some examples are considered to elucidate this general description. Also contribution of the massless states to the interaction

Kazuya Yuasa, Hiromichi Nakazato

By making use of the Langevin equation with a kernel, it was shown that the Feynman measure exp(-S) can be realized in a restricted sense in a diffusive stochastic process, which diverges and has no equilibrium, for bottomless systems. In this paper, the dependence on the initial conditions and the temporal behavior are analyzed for 0-dim bottomless systems.

Tim R. Morris

In these lectures we describe the construction of a gauge invariant renormalization group equation for pure non-Abelian gauge theory. In the process, a non-perturbative gauge invariant continuum Wilsonian effective action is precisely defined. The formulation makes sense without gauge fixing and thus manifest gauge invariance may be preserved at all stages.

Volker D. Burkert

Open problems in the study of the nucleon structure using electromagnetic probes are discussed. The focus is on experimental aspects in the regime of strong interaction QCD. Significant progress in our understanding of the nucleon structure in this domain of QCD may be expected in the first decade of the next millenium. This is due to major experimental and

U. Nierste

I give a detailed introduction into the theoretical formalism for epsilon&#39;/epsilon, which measures direct CP-violation in K -> pi pi decays. The current status of hadronic matrix elements and the strange quark mass is discussed. Several possible explanations of the unexpectedly high experimental results for epsilon&#39;/epsilon are pointed out: A small s

Xiangdong Ji, Chung-Wen Kao, Jonathan Osborne

We calculate the forward spin-dependent photon-nucleon Compton amplitudes $S_1$ and $S_2$ as functions of photon energy $ν$ and mass $Q^2$ at the next-to-leading (${\cal O}(p^4)$) order in chiral perturbation theory, from which we extract the contribution to a generalized Drell-Hearn-Gerasimov sum rule at low $Q^2$. The result indicates a much rapid $Q^2$ va

Vittorio Del Duca, William B. Kilgore, Fabio Maltoni

We present the tree-level amplitudes involving one, two and three photons that are required for next-to-leading order QCD calculations of production rates of three final-state particles. We also present the required one-loop amplitudes in terms of previously published results.

P. Aurenche, M. Fontannaz, J. -Ph. Guillet, B. A. Kniehl

We review the phenomenology of pi^0 production at large transverse momentum in proton-induced collisions. Uncertainties in the next-to-leading-order predictions of Quantum Chromodynamics are discussed. The comparison with data reveals that the disagreement between theory and experiment lies essentially in an overall normalization factor. The situation for pi

A. Yu. Loginov, A. A. Sidorov, V. N. Stibunov

Influence of the effects of the pion-nucleon and nucleon-nucleon re-scattering on the polarization observables of the reaction gamma + d = p + p + pi- in Delta - isobar region is investigated. Pion-nucleon and nucleon-nucleon re-scattering are studied in the diagrammatic approach. Relativistic-invariant forms of the pion photoproduction and pion-nucleon scat

Muneyuki Ishida, Toshihiko Komada, Shin Ishida, Taku Ishida

The pi0 pi0 mass spectra and angular distributions around KK_bar-threshold and at 1.5 GeV in pp_bar(at rest) to 3pi0 in the Crystal Barrel experiment are reanalyzed by applying the new method, which is consistent with unitarity of S-matrix and expressed directly by resonance parameters. The effects of light sigma-meson production are clearly seen to improve