May 1999 arXiv papers — page 14

Andrea Refolli, Niccolo' Terzi, Daniela Zanon

We study the scattering of three gravitons in M-atrix theory at finite N. With a specific choice of the background we obtain the complete result up to two loops. The contributions from three-body forces agree with the ones presented in recent papers. We extend the calculation and evaluate the two-body exchanges as well. Such terms, somewhat difficult to isol

A. Silva, D. Urbano, T. Watabe, M. Fiolhais

We calculate the ratios E2/M1 and C2/M1 for the electroproduction of the $Δ$(1232) in the region of photon virtuality $0<-q^2<1$ GeV$^2$. The magnetic dipole amplitude M1 is also presented. The theory used is the chiral quark-soliton model, which is based in the instanton vaccum of the QCD. The calculations are performed in flavor SU(2) and SU(3) taking rota

Akinori Nishino, Hideaki Ujino, Miki Wadati

Extending a method developed by Takamura and Takano, we present the Rodrigues formula for the nonsymmetric multivariable Laguerre polynomials which form the orthogonal basis for the $B_{N}$-type Calogero model with distinguishable particles. Our construction makes it possible for the first time to algebraically generate all the nonsymmetric multivariable Lag

Shin&#39;ichi Nojiri, Sergei D. Odintsov

We discuss the quantum corrections to thermodynamics (and geometry) of S(A)dS BHs using large $N$ one-loop anomaly induced effective action for dilaton coupled matter (scalars and spinors). It is found the temperature, mass and entropy with account of quantum effects for multiply horizon SdS BH and SAdS BH what also gives the corresponding expressions for th

Eugene Kogan, Pier A. Mello, He Liqun

We propose an information-theoretic model for the transport of waves through a chaotic cavity in the presence of absorption. The entropy of the S-matrix statistical distribution is maximized, with the constraint $<Tr SS^{\dagger}> =αn$: n is the dimensionality of S, and $0\leq α\leq 1, α=0(1)$ meaning complete (no) absorption. For strong absorption our resul

Soon-Tae Hong, Yong-Wan Kim, Young-Jai Park

We apply the Batalin-Fradkin-Tyutin (BFT) method to the SU(2) Skyrmion to study the full symmetry structure of the model at the first class Hamiltonian level. On the other hand, we also analyze the symmetry structure of the action having the WZ term, which corresponds to this Hamiltonian, in the framework of the Lagrangian approach. Furthermore, following th

Dan Edidin, William Graham

The purpose of this paper is to prove an equivariant Riemann-Roch theorem for schemes or algebraic spaces with an action of a linear algebraic group $G$. For a $G$-space $X$, this theorem gives an isomorphism between a completion of the equivariant Grothendieck group and a completion of equivariant equivariant Chow groups. The key to proving this isomorphism

S. S. Somaroo, C. H. Tseng, T. F. Havel, R. Laflamme

We present a general scheme for performing a simulation of the dynamics of one quantum system using another. This scheme is used to experimentally simulate the dynamics of truncated quantum harmonic and anharmonic oscillators using nuclear magnetic resonance. We believe this to be the first explicit physical realization of such a simulation.

Guang-jiong Ni, Weimin Zhou, Jun Yan

The Klein paradox of Klein-Gordon (KG) equation is discussed to show that KG equation is self-consistent even at one-particle level and the wave function for antiparticle is uniquely determined by the reasonable explanation of Klein paradox. No concept of ``hole&#39;&#39; is needed.

Hans Halvorson, Rob Clifton

Given a state on an algebra of bounded quantum-mechanical observables (the self-adjoint part of a C*-algebra), we investigate those subalgebras that are maximal with respect to the property that the given state&#39;s restriction to the subalgebra is a mixture of dispersion-free states---what we call maximal &#34;beable&#34; subalgebras (borrowing a terminolo

Sameen Ahmed Khan, Modesto Pusterla

An interpretation of the ``halo problem&#39;&#39; in accelerators based on quantum-like diffraction is given. Comparison between this approach and the others based on classical mechanics equations is discussed.

V. Kapin, M. Inoue, Y. Iwashita, A. Noda

There are applications, which require MeV-range multiple-beams consisting of a large number of identical highly packed beamlets. The multiple-beam RFQ (MB-RFQ) arranged as a matrix array of longitudinal rod-electrodes is appropriate candidate. A configuration of MB-RFQ resonator should ensure identical quadrupole fields in every accelerating channel. The MB-

J. A. Gonzalez, A. Bellorin, L. E. Guerrero

We investigate (theoretically and numerically) the dynamics of a soliton moving in an asymmetrical potential well with a finite barrier. For large values of the width of the well, the width of the barrier and/or the height of the barrier, the soliton behaves classically. On the other hand, we obtain the conditions for the existence of soliton tunneling with

M. -Th. Huett, A. I. L&#39;vov, A. I. Milstein, M. Schumacher

The concept of Compton scattering by even-even nuclei from giant-resonance to nucleon-resonance energies and the status of experimental and theoretical researches in this field are outlined. Nuclear Compton scattering in the giant-resonance energy-region provides information on the dynamical properties of the in-medium mass of the nucleon. The electromagneti

A. Bonasera

We discuss the dynamics of quarks within a Vlasov approach. We use an interquark ($qq$) potential consistent with the indications of Lattice QCD calculations and containing a Coulomb term, a confining part and a spin dependent term. Hadrons masses are shown to arise from the interplay of these three terms plus the Fermi motion and the finite masses of the qu

Fabio Giannoni, Paolo Piccione, Daniel V. Tausk

The travel time brachistochrone curves in a general relativistic framework are timelike curves, satisfying a suitable conservation law with respect to a an observer field, that are stationary points of the travel time functional. In this paper we develop a global variational theory for brachistochrones joining an event $p$ and the worldline of an observer $γ

Ph. Ellia, D. Franco

We prove that a smooth surface, non of general type, in projective four-space, which lies on a quartic hypersurface with isolated singularities has degree at most 27 (in fact we prove a slightly more general result).

Frank Hausser, Florian Nill

We generalize the fundamental structure Theorem on Hopf (bi)-modules by Larson and Sweedler to quasi-Hopf algebras H. If H is finite dimensional this proves the existence and uniqueness (up to scalar multiples) of integrals in H. Among other applications we prove a Maschke type Theorem for diagonal crossed products as constructed by the authors.

Arturo Magidin

Dominions, in the sense of Isbell, are investigated in the context of decomposable varieties of groups. An upper and lower bound for dominions in such a variety is given in terms of the two varietal factors, and the internal structure of the group being analyzed. Finally, the following result is established: If a variety ${\cal N}$ has instances of nontrivia

Arturo Magidin

This paper has been withdrawn. The results are now part of math.GR/9804072.

Arturo Magidin

In the first part, we prove that the dominion (in the sense of Isbell) of a subgroup of a finitely generated nilpotent group is trivial in the category of all nilpotent groups. In the second part, we show that the dominion of a subgroup of a finitely generated nilpotent group of class two is trivial in the category of all metabelian nilpotent groups.

Arturo Magidin

We investigate the concept of dominion (in the sense of Isbell) in several varieties of nilpotent groups. We obtain a full description of dominions in the variety of nilpotent groups of class at most two. Then we look at the behavior of dominions of subgroups of groups in ${\cal N}_2$ when taken in the context of ${\cal N}_c$ with $c>2$. Finally we establish

Arturo Magidin

Using the description of dominions in the variety of nilpotent groups of class at most two, we give a characterization of which groups are absolutely closed in this variety. We use the general result to derive an easier characterization for some subclasses; e.g. an abelian group $G$ is absolutely closed in ${\cal N}_2$ if and only if $G/pG$ is cyclic for eve

James Bardeen, Gary T. Horowitz

We study the near horizon limit of a four dimensional extreme rotating black hole. The limiting metric is a completely nonsingular vacuum solution, with an enhanced symmetry group SL(2,R) x U(1). We show that many of the properties of this solution are similar to the AdS_2 x S^2 geometry arising in the near horizon limit of extreme charged black holes. In pa

L. E. Ibanez, R. Rabadan, A. M. Uranga

Compact Type IIB D=4, N=1 orientifolds have certain U(1) sigma model symmetries at the level of the effective Lagrangian. These symmetries are generically anomalous. We study the particular case of $Z_N$ orientifolds and find that these anomalies may be cancelled by a generalized Green-Schwarz mechanism. This mechanism works by the exchange of twisted RR-fie

Per Berglund, Eric G. Gimon, Djordje Minic

We list the spectrum generating algebras for string theory and M-theory compactified on various backgrounds of the form $AdS_{d+1} \times S^n$. We identify the representations of these algebras which make up the classical supergravity spectra and argue for the presence of these spectrum generating algebras in the classical string/M-theory. We also discuss th

M. Cvetic, James T. Liu, H. Lu, C. N. Pope

Kaluza-Klein sphere reductions of supergravities that admit AdS x Sphere vacuum solutions are believed to be consistent. The examples include the S^4 and S^7 reductions of eleven-dimensional supergravity, and the S^5 reduction of ten-dimensional type IIB supergravity. In this paper we provide evidence that sphere reductions of supergravities that admit inste

J. -M. Chung

We calculate the induced Lorentz- and CPT-violating Chern-Simons term arising from the Lorentz- and CPT-violating sector of quantum electrodynamics with a $b_μ\barψγ^μγ_5ψ$ term. The result to all orders in $b$ coincides with the previous linear-in-$b$ calulation by Chung and Oh [hep-th/9812132] as well as Jackiw and Kostelecký [Phys. Rev. Lett. {\bf 82}, 35

A. Niégawa

This paper describes perturbative framework, on the basis of the closed-time-path formalism, in terms of quasiparticle picture for studying quasiuniform relativistic quantum field systems near equilibrium and nonequilibrium quasistationary systems. Two calculational schemes are introduced, the one is formulated on the basis of the initial-particle distributi

C. D. Fosco, J. C. Le Guillou

The paper has been temporarily withdrawn.

Daniel Boer

We investigate leading twist transverse momentum dependent origins of transverse spin asymmetries in hadron-hadron collisions. The chiral-odd T-odd distribution function with intrinsic transverse momentum dependence, which would signal an intrinsic handedness of quarks inside a hadron, could account for single spin asymmetries and at the same time for the la

J. L. Diaz-Cruz, J. M. Hernandez, J. J. Toscano

We study the inter-relations that exist between the present experimental bounds on the Higgs mass, as obtained from radiative corrections to $m_W$, and the effective parameters, $α_i$ and $Λ$. We find that the SM bounds on $m_H$, arising from a precise determination of the $m_W$ mass, can be substantially modified by the presence of dimension-6 operators whi

Thomas D. Cohen, Xiangdong Ji

We show that the Drell-Hearn-Gerasimov sum rule for the nucleon is entirely saturated by the Δresonance in the limit of a large number of colors, N_c \to \infty. Corrections are at relative order 1/N_c^2.

D. I. Kazakov

The status of the Higgs boson mass in the Standard Model and its supersymmetric extensions is reviewed and the perspectives of Higgs searches are discussed. The parameter space of the Minimal Supersymmetric Standard Model (MSSM) is analysed with the emphasis on the lightest Higgs mass. The infrared behaviour of renormalization group equations for the paramet

H. Weigel, E. Ruiz Arriola, L. Gamberg

We provide a consistent regularization procedure for calculating hadron structure functions in a chiral quark model. The structure functions are extracted from the absorptive part of the forward Compton amplitude in the Bjorken limit. Since this amplitude is obtained as a time-ordered correlation function its regularization is consistently determined from th

Joannis Papavassiliou

The consistent description of unstable particles within the framework of perturbative gauge field theories necessitates the definition and resummation of off-shell Green&#39;s functions, which must respect several crucial physical requirements. We present the solution to this problem at one-loop, using the pinch technique.

Sandhya Choubey, Kamales Kar

The neutrinos from galactic supernovae can be detected by the Sudbury Neutrino Observatory and the Super-Kamiokande. The effect of neutrino mass can show up in the observed neutrino signal by (i) delay in the time of flight and (ii) distortion of the neutrino energy spectrum due to flavor mixing. We discuss a combination of the two effects for both charged a

M. R. Pennington

The riddle of the sigma is recast in a way that tries to differentiate fact from fiction as a basis for future/further discussion. By doing this, it is hoped that the role of the sigma as dominating the ubiquitous $ππ$ interactions below 1 GeV and its relation to the QCD vacuum can be clarified.

A. Anastasiadis, K. Kleidis, H. Varvoglis

The interaction of charged particles, moving in a uniform magnetic field, with a plane-polarized gravitational wave is considered using the Fokker-Planck- Kolmogorov (FPK) approach. By using a stochasticity criterion, we determine the exact locations in phase space, where resonance overlapping occurs. We investigate the diffusion of orbits around each primar

K. Kleidis, D. B. Papadopoulos

In the context of higher-dimensional cosmologies with isotropic visible and internal space and multi-perfect fluid matter, we study the conditions under which adiabatic expansion of the visoble external space is possible, when a time-dependent internal space is present. The analysis is based on a reinterpretation of the four-dimensional stress-energy tensor

K. Kleidis, A. Kouirukidis, D. B. Papadopoulos, H. Varvoglis

Ten-dimensional models, arising from a gravitational action which includes terms up to the fourth order in curvature tensor, are discussed. The spacetime consists of one timelike dimension and two maximally symmetric subspaces, filled with matter in the form of an anisotropic fluid. Numerical integration of the cosmological field equations indicates that exp

K. Kleidis, D. B. Papadopoulos

Massive scalar particle production, due to the anisotropic evolution of a five-dimensional spacetime, is considered in the context of a quadratic Lagrangian theory of gravity. Those particles, corresponding to field modes with non-vanishing momentum component along the fifth dimension, are created mostly in the neighbourhood of a singular epoch where only th

Hisao Suzuki, Eiichi Takasugi, Hiroshi Umetsu

The analytic solution of Teukolsky equation in Kerr-de Sitter and Kerr-Newman-de Sitter geometries is presented and the properties of the solution are examined. In particular, we show that our solution satisfies the Teukolsky-Starobinsky identities explicitly and fix the relative normalization between solutions with the spin weight $s$ and $-s$.

Sascha Husa, Jeffrey Winicour

We study event horizons of non-axisymmetric black holes and show how features found in axisymmetric studies of colliding black holes and of toroidal black holes are non-generic and how new features emerge. Most of the details of black hole formation and black hole merger are known only in the axisymmetric case, in which numerical evolution has successfully p

Gennady P. Berman, David K. Campbell, Gary D. Doolen, Kirill E. Nagaev

We study numerically the process of nuclear spin measurement in a solid-state quantum computer of the type proposed by Kane by modeling the quantum dynamics of two coupled nuclear spins on $^{31}$P donors implanted in silicon. We estimate the minimum measurement time necessary for the reliable transfer of quantum information from the nuclear spin subsystem t

M. I. Lubin, J. H. Bylaska, J. H. Weare

The solvation of Al and its hydrolyzed species in water clusters has been studied by means of ab initio molecular dynamics simulations. The hexa-hydrate aluminum ion formed a stable complex in the finite temperature cluster simulation of one aluminum ion and 16 waters. The average dipole moment of strongly polarized hydrated water molecules in the first solv

Mark A. Novotny

An introduction to the Propp-Wilson method of coupling-from-the-past for the Ising model is presented. It enables one to obtain exact samples from the equilibrium spin distribution for ferromagnetic interactions. Both uniform and random quenched magnetic fields are included. The time to couple from the past and its standard deviation are shown as functions o

A. I. Belousov, Yu. E. Lozovik

By path integral Monte Carlo simulations we study the phase diagram of two - dimensional mesoscopic clusters formed by electrons in a semiconductor quantum dot or by indirect magnetoexcitons in double quantum dots. At zero (or sufficiently small) temperature, as quantum fluctuations of particles increase, two types of quantum disordering phenomena take place

G. E. Astrakharchik, A. I. Belousov, Yu. E. Lozovik

Two-dimensional classical cluster of particles interacting through a screened Coulomb potential is studied. This system can be used as a model for &#34;dusty particles&#34; in high-frequency discharge plasma. For systems consisting of N = 2 - 40 particles and confined by a harmonic potential we find ground-state configurations, eigenfrequencies and eigenvect

Carlos Frontera, Eduard Vives

Intensive numerical studies of exact ground states of the 2-d ferromagnetic random field Ising model at T=0 with gaussian distribution of fields are presented. Standard finite size scaling analysis of the data suggests the existence of a transition at sigma_c= 0.64 +/- 0.08. Results are compared with existing theories and with the study of metastable avalanc

U. Hansen, P. Vogl, V. Fiorentini

We discuss a computationally efficient classical many-body potential designed to model the Al-Al interaction in a wide range of bonding geometries. We show that the potential yields results in properties in excellent agreement with experiment and ab initio results for a number of bulk and surface properties, among others for surface and step formation energi

V. Fiorentini, F. Bernardini, F. Della Sala, A. Di Carlo

Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we discuss the background theory, the role of spontaneous polarization in this context, and the practical implications of built-

A. S. Alexandrov, C. J. Dent

A theory of angle-resolved photoemission (ARPES) in doped cuprates and other charge-transfer Mott insulators is developed taking into account the realistic (LDA+U) band structure, (bi)polaron formation due to the strong electron-phonon interaction, and a random field potential. In most of these materials the first band to be doped is the oxygen band inside t

M. Nitti, A. Torcini, S. Ruffo

A detailed description and validation of a recently developed integration scheme is here reported for one- and two-dimensional reaction-diffusion models. As paradigmatic examples of this class of partial differential equations the complex Ginzburg-Landau and the Fitzhugh-Nagumo equations have been analyzed. The novel algorithm has precision and stability com

Patrick Ahlrichs, Burkhard Duenweg

In this paper we establish a new efficient method for simulating polymer-solvent systems which combines a lattice Boltzmann approach for the fluid with a continuum molecular dynamics (MD) model for the polymer chain. The two parts are coupled by a simple dissipative force while the system is driven by stochastic forces added to both the fluid and the polymer

Tomoya Isoshima, Kazushige Machida, Tetsuo Ohmi

The spatial structure of the spinor Bose-Einstein condensates with the spin degrees of freedom is analyzed based on the generalized Gross-Pitaevskii equation (GP) in the light of the present spin domain experiment on m_F=\pm 1, and 0 of the hyperfine state F=1 of ^{23}Na atom gases. The GP solutions in three- and one-spatial dimensional cases reproduce the o

P. D. Sacramento

We calculate the quasiparticle contribution to the zero temperature Hall conductance of two-dimensional extreme type-II superconductors in a high magnetic field, using the Landau basis. As one enters the superconducting phase the Hall conductance is renormalized to smaller values, with respect to the normal state result, until a quantum level-crossing transi

P. D. Sacramento

We show that gapless superconductivity of a strongly type-II superconductor in a high magnetic field prevails in the presence of disorder, suggesting a topological nature. We calculate the density of states of the Bogoliubov-de Gennes quasiparticles for a two-dimensional inhomogeneous system in both cases of weak and strong disorder. In the limit of very wea

Hideaki Ujino, Miki Wadati

Applying a method developed by Takamura and Takano for the nonsymmetric Jack polynomial, we present the Rodrigues formula for the nonsymmetric multivariable Hermite polynomial.

Himanshu Agrawal

This study aims at finding a method for constructing molecular dynamics like models using the formalism of cellular automata for fast simulation of fluid dynamic systems (including compressible phenomena). In as much as the results indicate, the attempt is successful. A systematic method for constructing cellular automata models of fluid dynamic systems is d

Hiroya Nakao

A two-dimensional system of non-locally coupled complex Ginzburg-Landau oscillators is investigated numerically for the first time. As already known for the one-dimensional case, the system exhibits anomalous spatio-temporal chaos characterized by power-law spatial correlations. In this chaotic regime, the amplitude difference between neighboring elements sh

Wen Xu, Li-Zhi Fang

The recently observed bright optical transients(OT) of high redshift GRBs indicate that they are in a violent dynamical state. We think it is reasonable to assume that the GRBs form in the environment of gravitationally collapsed halos of the cosmic matter field, and we investigate the basic parameters of the halos which are favored to host GRBs. If the harb

I. N. Reid, J. D. Kirkpatrick, J. Liebert, A. Burrows

Analysis of initial observations from near-infrared sky surveys has shown that the resulting photometric catalogues, combined with far-red optical data, provide an extremely effective method of finding isolated, very low-temperature objects in the general field. Follow-up observations have already identified more than 25 sources with temperatures cooler than

F. Bertola, E. M. Corsini, J. C. Vega Beltran, A. Pizzella

The R-band isophotal map of the Sa galaxy NGC 4698 shows that the inner region of the bulge structure is elongated perpendicularly to the major axis of the disk, this is also true for the outer parts of the bulge if a parametric photometric decomposition is adopted. At the same time the stellar component is characterized by an inner velocity gradient and a c

John E. Gizis, I. Neill Reid, David G. Monet

We present results of a search for very low mass stars and brown dwarfs towards the central region of the Hyades cluster. Using Two Micron All Sky Survey (2MASS) near-infrared and Second Palomar Sky Survey (POSSII) optical photometry, we select candidates corresponding to spectral types M8 through L4 at the distance of the Hyades. Spectroscopic followup data

S. Silich, J. Franco

Here we present a possible solution to the apparent discrepancy between the observed properties of LMC bubbles and the standard, constant density bubble model. A two-dimensional model of a wind-driven bubble expanding from a flattened giant molecular cloud is examined. We conclude that the expansion velocities derived from spherically symmetric models are no

V. Celebonovic

This is a short review of the main results on the equation of state of a Bose gas.Some known results are expressed in a new form,and their possible applications in astrophysics and solid state physics are pointed out.

C. M. Rudge, D. J. Raine

We have previously shown that the linewidth distribution in AGN can be accounted for by an axisymmetric broad emission line region. In this paper we show that the linewidth distribution changes with redshift and that these changes are dependent on H_0 and q_0. We show that relatively small samples of AGN at high redshift with measured linewidth at half maxim

Jocelyn Tomkin, David L. Lambert

We report the first extensive study of stellar Rb abundances. High-resolution spectra have been used to determine, or set upper limits on, the abundances of this heavy element and the associated elements Y, Zr, and Ba in 44 dwarfs and giants with metallicities spanning the range -2.0 <[Fe/H] < 0.0. In metal-deficient stars Rb is systematically overabundant r

F. R. Pearce, A. Jenkins, C. S. Frenk, J. M. Colberg

We discuss early results from the first large N-body/hydrodynamical simulation to resolve the formation of galaxies in a cold dark matter universe. The simulation follows the formation of galaxies by gas cooling within dark halos of mass a few times $10^{11}\Msun$ and above, in a flat universe with a positive cosmological constant. Over 2200 galaxies form in

A. S. Majumdar

We describe extended inflation and its typical problems. We then briefly review essential features of Kaluza-Klein theory, and show that it leads to a scenario of inflationary cosmology in four dimensions. The problem of stable compactification of extra spatial dimensions is discussed. The requirements for successful extended inflation lead to constraints on

A. A. Panferov

The relativistic jets of SS433 are outstanding for their optical thermal radiation.The radiation is produced by small clouds ($10^8$ cm) whose lifetime is about $10^3$ times larger than the gas-dynamical crushing time. We show that the clouds reside in thermal and dynamical balance as long as they collisionally interact with the wind of the supercritical acc

V. F. Litvin, V. V. Orlov, S. A. Matveef, W. E. Pereira

We carried out a search for peak inhomogeneities in the distribution of matter - namely clumps and voids, within the range Z ~ 1-3. We used a new method, based on the lensing of quasars by a combination of lenses, belonging to the above sought inhomogeneities in the matter distribution. This work confirms the evidence of the existence of inhomogeneities foun

Wen Xu, Li-Zhi Fang, Zugan Deng

We investigated the structures on scales beyond the typical clusters of galaxies. These structures are crucial to understand the cosmic gravitational clustering in the pre-virialized stage, or quasilinear règime. Based on the multi-resolution analysis of the discrete wavelet transformation, we got statistical available ensembles of $r_{cl}$-clusters, i.e. th

Inger Jorgensen, Marijn Franx, Jens Hjorth, Pieter G. van Dokkum

New photometry and spectroscopy for the two rich clusters Abell 665 and Abell 2218 are presented and used to establish the Fundamental Plane (FP) for the clusters. The FP for these two clusters adds important knowledge about the properties of E and S0 galaxies in the relatively unexplored redshift interval 0.05 to 0.3. We have compared the FP for A665 and A2

Alan Stockton, Gabriela Canalizo, Susan E. Ridgway

We have obtained imaging in the K&#39; band (~I-band rest frame) of the z=1.786 radio galaxy 3C 294 with the 36-element curvature-sensing adaptive optics system Hokupa`a and the Canada-France-Hawaii Telescope. At a resolution of < \~0.&#34;15, the galaxy is seen as a group of small but resolved knots distributed over a roughly triangular region ~1.&#34;4 acr

A. Muecke, J. P. Rachen, R. Engel, R. J. Protheroe

Photomeson production is the main energy loss for relativistic nucleons in dense radiation fields like the cosmic microwave background and the radiation fields in Gamma Ray Bursts (GRB) and jets of Active Galactic Nuclei (AGN). In this paper we study photomeson production in typical GRB and AGN jet radiation fields by using the recently developed Monte Carlo

Valentin D. Ivanov, Almudena Alonso-Herrero, Marcia J. Rieke, Don McCarthy

We present for the first time infrared observations of the nearby highly obscured galaxy Dwingeloo 1 (Dw1), including deep H-band imaging covering a total of 4.9x4.9 arcmin, together with J and Ks imaging of the central 2.5x2.5 arcmin. We used the small dispersion of the intrinsic infrared colors of spiral galaxies to determine an infrared H-band extinction

Jason D. Fiege, Ralph E. Pudritz

We develop a theory for filamentary molecular clouds including the effects of ordered magnetic fields, and external pressure. We first derive a form of the virial equation appropriate for filamentary clouds. By comparing with observational results collected from the literature, we find that the fields are likely helical. Secondly, we construct numerical, MHD

S. H. Rhie, D. P. Bennett, A. C. Becker, B. A. Peterson

We present observations of microlensing event MACHO-98-BLG-35 which reached a peak magnification factor of almost 80. These observations by the Microlensing Planet Search (MPS) and the MOA Collaborations place strong constraints on the possible planetary system of the lens star and show intriguing evidence for a low mass planet with a mass fraction $4\times

J. S. Olafsen, J. S. Urbach

Velocity distributions in a vibrated granular monolayer are investigated experimentally. Non-Gaussian velocity distributions are observed at low vibration amplitudes but cross over smoothly to Gaussian distributions as the amplitude is increased. Cross-correlations between fluctuations in density and temperature are present only when the velocity distributio

Thomas Wynter

High energy fixed angle scattering is studied in matrix string theory. The saddle point world sheet configurations, which give the dominant contributions to the string theory amplitude, are taken as classical backgrounds in matrix string theory. A one loop fluctuation analysis about the classical background is performed. An exact treatment of the fermionic a

M. Gierlinski, A. A. Zdziarski, J. Poutanen, P. S. Coppi

We present X-ray/gamma-ray spectra of Cyg X-1 observed during the transition from the hard to the soft state and in the soft state by ASCA, RXTE and OSSE in 1996 May and June. The spectra consist of a dominant soft component below ~2 keV and a power-law-like continuum extending to at least ~800 keV. We interpret them as emission from an optically-thick, cold

A. Kambili, G. Fagas, Vladimir I. Fal&#39;ko, C. J. Lambert

We present an analysis of acoustic phonon propagation through long, free-standing, insulating wires with rough surfaces. Due to a crossover from ballistic propagation of the lowest-frequency phonon mode at $ω<ω_{1}=πc/W$ to a diffusive (or even localized) behavior upon the increase of phonon frequency, followed by re-entrance into the quasi-ballistic regime,

A. V. Bolsinov, I. A. Taimanov

An example of a real-analytic metric on a compact manifold whose geodesic flow is Liouville integrable by $C^\infty$ functions and has positive topological entropy is constructed.

V. A. Smirnov

The dimensionally regularized massless on-shell double box Feynman diagram with powers of propagators equal to one is analytically evaluated for general values of the Mandelstam variables s and t. An explicit result is expressed either in terms of polylogarithms Li_a(-t/s), up to a=4, and generalized polylogarithms S_{a,b}(-t/s), with a=1,2 and b=2, or in te

I. Daumont, T. Dombre, J. -L. Gilson

It has been shown recently that intermittency of the Gledzer Ohkitani Yamada (GOY) shell model of turbulence has to be related to singular structures whose dynamics in the inertial range includes interactions with a background of fluctuations. In this paper we propose a statistical theory of these objects by modelling the incoherent background as a Gaussian

Thomas Nowotny, Heiko Patzlaff, Ulrich Behn

We consider the one dimensional classical Ising model in a symmetric dichotomous random field. The problem is reduced to a random iterated function system for an effective field. The D_q-spectrum of the invariant measure of this effective field exhibits a sharp drop of all D_q with q < 0 at some critical strength of the random field. We introduce the concept

Igor Batalin, Robert Marnelius

The recently introduced quantum antibracket is further generalized allowing for the defining odd operator Q to be arbitrary. We give exact formulas for higher quantum antibrackets of arbitrary orders and their generalized Jacobi identities. Their applications to BV-quantization and BFV-BRST quantization are then reviewed including some new aspects.

Giovanni Felder, Anke Schorr

We extend Sklyanin&#39;s method of separation of variables to quantum integrable models associated to elliptic curves. After reviewing the differential case, the elliptic Gaudin model studied by Enriquez, Feigin and Rubtsov, we consider the difference case and find a class of transfer matrices whose eigenvalue problem can be solved by separation of variables

K. H. Andersen, T. Bohr, M. H. Jensen, J. L. Nielsen

We study the propagation of localised disturbances in a turbulent, but momentarily quiescent and unforced shell model (an approximation of the Navier-Stokes equations on a set of exponentially spaced momentum shells). These disturbances represent bursts of turbulence travelling down the inertial range, which is thought to be responsible for the intermittency

C. Boros, Meng Ta-chung, R. Rittel, K. Tabelow

This is the extensive follow-up report of a recent Letter in which the existence of self-organized criticality (SOC) in systems of interacting soft gluons is proposed, and its consequences for inelastic diffractive scattering processes are discussed. It is pointed out, that color-singlet gluon-clusters can be formed in hadrons as a consequence of SOC in syst

D. Falcone

A nearly historical account of quark mass matrix models is given, and the structure of quark mass matrices in the Standard Model is studied. For a minimal parameter basis suggested earlier, where $M_u$ is diagonal and $M_{d11}$, $M_{d13}$, $M_{d31}$ are zero, the dependence of mass matrices on the CP violating phase $δ$ of $V_{CKM}$ is reported: all paramete

S. C. Erwin, A. A. Baski, L. J. Whitman, R. E. Rudd

We describe in greater detail the exactly solvable microscopic model we have developed for analyzing the strain-mediated interaction of vacancy lines in a pseudomorphic adsorbate system (Phys. Rev. Lett., to appear). The model is applied to Ga/Si(112) by extracting values for the microscopic parameters from total-energy calculations. The results, which are i

Zahid Zakir

The 4-index energy-momentum tensors for gravitation and matter are analyzed on the basis of new equations for the gravitational field with the Riemann tensor. Some properties of the such defined gravitational energy are discussed.

Lieven M. K. Vandersypen, Costantino S. Yannoni, Mark H. Sherwood, Isaac L. Chuang

We report the first use of &#34;logical labeling&#34; to perform a quantum computation with a room-temperature bulk system. This method entails the selection of a subsystem which behaves as if it were at zero temperature - except for a decrease in signal strength - conditioned upon the state of the remaining system. No averaging over differently prepared mol

S. Hill, J. S. Brooks, Z. Q. Mao, Y. Maeno

We have measured the cyclotron masses in Sr2RuO4 through the observation of periodic-orbit-resonances - a magnetic resonance technique closely related to cyclotron resonance. We obtain values for the alpha, beta and gamma Fermi surfaces of (4.33+/-0.05)me, (5.81+/-0.03)me and (9.71+/-0.11)me respectively. The appreciable differences between these results and

Aldo H. Romero, David W. Brown, Katja Lindenberg

We apply weak-coupling perturbation theory and strong-coupling perturbation theory to the Holstein molecular crystal model in order to elucidate the effects of anisotropy on polaron properties in D dimensions. The ground state energy is considered as a primary criterion through which to study the effects of anisotropy on the self-trapping transition, the sel

A. Burrows, T. Young, P. A. Pinto, R. Eastman

We have developed an implicit, multi-group, time-dependent, spherical neutrino transport code based on the Feautrier variables, the tangent-ray method, and accelerated ${\bf Λ}$ iteration. The code achieves high angular resolution, is good to O($v/c$), is equivalent to a Boltzmann solver (without gravitational redshifts), and solves the transport equation at

Martin Andler, Alexander Dvorsky, Siddhartha Sahi

In 1979, M. Kashiwara and M. Vergne formulated a conjecture on a Lie group G which implies that the Duflo isomorphism of Z(g) and S(g)^g extends to a natural module isomorphism between the spaces of germs of invariant distributions on G and g=Lie(G), respectively. They also proved their conjecture for G solvable. Using Kontsevich&#39;s deformation quantizati