September 2000 arXiv papers — page 17

Gernot Münster, Sergei B. Rutkevich

In many systems in condensed matter physics and quantum field theory, first order phase transitions are initiated by the nucleation of bubbles of the stable phase. Traditionally, this process is described by the semiclassical nucleation theory developed by Langer and, in the context of quantum field theory, by Callan and Coleman. They have shown that the nuc

J. S. Frasier, V. Celli

We present numerical simulations of a theory of resonant processes in a frozen gas of excited atoms interacting via dipole-dipole potentials that vary as $r^{-3}$, where $r$ is the interatomic separation. The simulations calculate time-dependent averages of transition amplitudes and transition probabilities for a single atom in a given state interacting reso

Garth Illingworth

Within just the last few years, we have advanced from knowing only a few galaxies at z>2 to having redshifts for nearly 1000 z~2-5 objects. The majority of this sample has been detected through the photometric ``drop-out'' technique used so successfully by Steidel and his collaborators. In addition, a handful of objects have already been detected at

Garth Illingworth, Daniel Kelson, Pieter van Dokkum, Marijn Franx

We have witnessed a dramatic increase over the last five years in results on distant galaxies, in large part because of the high resolution imaging capability of HST, and the multiobject spectroscopic capability of the Keck telescopes. Our program to obtain wide-field, multi-color WFPC2 mosaics with HST of intermediate redshift clusters, and spectroscopic me

Scott J. Kenyon, Benjamin C. Bromley

We describe gravitational stirring models of planetary debris disks using a new multi-annulus planetesimal evolution code. The current code includes gravitational stirring and dynamical friction; future studies will include coagulation, fragmentation, Poynting-Robertson drag, and other physical processes. We use the results of our calculations to investigate

R. Iaria, L. Burderi, T. Di Salvo, A. La Barbera

We report on the spectral analysis of the peculiar source Cir X-1 observed by the BeppoSAX satellite when the X-ray source was near the periastron. A flare lasting $\sim 6 \times 10^3$ s is present at the beginning of the observation. The luminosity during the persistent emission is $1 \times 10^{38}$ erg s$^{-1}$, while during the flare is $2 \times 10^{38}

N. C. Santos, G. Israelian, M. Mayor

We present the chemical analysis of a new set of stars known to harbor low mass companions, namely HD 1237, HD 52265, HD 82943, HD 83443, HD 169830, and HD 202206. In addition, we have also analyzed HD 13445 and HD 7528}, already studied elsewhere. The abundances of C and alpha-elements O, S, Si, Ca and Ti are presented and discussed in the context of the me

Renato Falomo, Jari Kotilainen, Aldo Treves

We present high spatial resolution near-infrared H-band (1.65 microns) images, taken with ISAAC on UT1 of ESO VLT, of three radio-loud quasars at z = 1.5, as a pilot study for imaging of a larger sample of radio-loud and radio-quiet quasars in the redshift range 1 < z < 2. We are able to clearly detect the host galaxy in two quasars (PKS 0000-177 and PKS 034

D. Bersier

I determine a distance to the Fornax dwarf galaxy using stars in the red clump and at the tip of the red giant branch. They are in very good agreement, with $μ_0 = 20.66 mag$. Comparing the magnitudes of the tip of the red giant branch and of the red clump in Fornax, Carina and the Magellanic Clouds, I propose a possible solution to the problem of the discre

R. D. Jeffries, T. Naylor

We take a critical look at the lithium depletion boundary (LDB) technique that has recently been used to derive the ages of open clusters. We identify the sources of experimental and systematic error and show that the probable errors are larger by approximately a factor two than presently claimed in the literature. We then use the Pleiades LDB age and photom

E. Diolaiti, O. Bendinelli, D. Bonaccini, L. Close

We describe a new code for the deep analysis of stellar fields, designed for Adaptive Optics Nyquist-sampled images with high and low Strehl ratio. The Point Spread Function is extracted directly from the image frame, to take into account the actual structure of the instrumental response and the atmospheric effects. The code is written in IDL language and or

Paolo Todini, Andrea Ferrara

We have investigated the formation of dust in the ejecta of Type II supernovae (SNe), mostly of primordial composition, to answer the question of where are the first solid particles formed in the universe. However, we have also considered non-zero progenitor&#39;s metallicity values up to Z=Zsun. The calculations are based on standard nucleation theory and t

D. J. Saikia, S. Jeyakumar, C. J. Salter, P. Thomasson

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from different samples of radio sources, and compare these with the larger sources of similar luminosity to understand their evo

G. Chabrier, I. Baraffe, F. Allard, P. Hauschildt

We consider the depletion of primordial deuterium in the interior of substellar objects as a function of mass, age and absolute magnitude in several photometric passbands. We characterize potential spectroscopic signatures of deuterium in the lines of deuterated water HDO. These results will serve as a useful, independent diagnostic to characterize the mass

Noam Soker, Raymond E. White, Laurence P. David, Brian R. McNamara

We propose that the outer portions of cooling flows (CFs) in clusters of galaxies are frequently disrupted by radio jets, and that their effective ages are much shorter than the cluster ages. The inner regions, where the gas density is higher, are more difficult to disrupt, and may continue to harbor CFs even after disruption events. The main assumption of t

David V. Bowen, Raul Jimenez, Edward B. Jenkins, Max Pettini

We present images and spectroscopy of objects close to the sightline of Q2302+029 in order to search for galaxies responsible for the remarkable z=0.7 high-ionization absorption line system found by Jannuzi et al (1996). This system shows `normal&#39; narrow OVI, NV, and CIV lines superimposed on broader (3,000-5,000 km/s wide), unsaturated absorption trough

T. E. Clarke, M. Gladders, G. Mallen-Ornelas

We present the current distance estimates to 11 intermediate velocity clouds (IVCs) which are part of the David Dunlap Observatory Intermediate Velocity Cloud (DDO IVC) Distance Project (Clarke et al. 1999). We briefly discuss constraints these place on infall models and show the potential of IVCs to constrain the radial distribution of hot gas in the Galaxy

Igor F. Herbut

Screening of an external random potential by a two dimensional (2D) Fermi liquid may be strongly dependent on the degree of its polarization. This is considered as a possible mechanism for the observed strong magnetoresistance of the 2D electron liquid in the magnetic field parallel to the electron plane. A Hartree-Fock calculation for the weakly disordered

Alec Maassen van den Brink

We evaluate the detector nonideality (and energy sensitivity) of a normal-state single-electron transistor (SET) in the cotunneling regime in a two-charge-state approximation. For small conductances and at zero temperature, the SET&#39;s performance as a charge-qubit readout device is characterized by a universal one-parameter function. The result shows that

Kevin M. O&#39;Connor, William K. Wootters

Consider a ring of N qubits in a translationally invariant quantum state. We ask to what extent each pair of nearest neighbors can be entangled. Under certain assumptions about the form of the state, we find a formula for the maximum possible nearest-neighbor entanglement. We then compare this maximum with the entanglement achieved by the ground state of an

Mark Laidlaw

We develop a method in which it is possible to calculate one loop corrections to the noncommutativity parameter for open strings in a background F field. We reproduce known disk level results, and find that annulus corrections give the same structure multiplied by a constant due to the tachyon.

Guy D. Moore, Kari Rummukainen

We present a lattice method to compute bubble nucleation rates at radiatively induced first order phase transitions, in high temperature, weakly coupled field theories, nonperturbatively. A generalization of Langer&#39;s approach, it makes no recourse to saddle point expansions and includes completely the dynamical prefactor. We test the technique by applyin

Hajime Yoshino, Anael Lemaitre, Jean-Philippe Bouchaud

We study domain growth dynamics when the target state is suddenly changed on all length scales. This procedure mimics the `chaos&#39; effect postulated by the droplet theory of spin-glasses, and allows us to investigate in details its various dynamical consequences. We study the problem by a variety of methods, including scaling arguments, analytical solutio

Michael Entov

Given a closed symplectic manifold $(M,ω)$ we introduce a certain quantity associated to a tuple of conjugacy classes in the universal cover of the group ${\hbox{\it Ham}} (M,ω)$ by means of the Hofer metric on ${\hbox{\it Ham}} (M,ω)$. We use pseudo-holomorphic curves involved in the definition of the multiplicative structure on the Floer cohomology of a sy

D. Porras, J. Fernandez-Rossier, C. Tejedor

We discuss Fermi-edge singularity effects on the linear and nonlinear transient response of an electron gas in a doped semiconductor. We use a bosonization scheme to describe the low energy excitations, which allows to compute the time and temperature dependence of the response functions. Coherent control of the energy absorption at resonance is analyzed in

Donam Youm

We study BPS solutions for a self-dual string and a neutral string in M5-brane worldvolume theory with constant three-form field. We further generalize such solitons to superpose with a calibrated surface. We also study a traveling wave on a calibrated surface in the constant three-form field background.

M. Banados

We consider five-dimensional S(2,2|N) Chern-Simons supergravity on M_4 * R . By fine-tuning the Kaluza-Klein reduction to make the 4d cosmological constant equal zero, it is shown that selfdual curvatures on M_4 provide exact solutions to the equations of motion if N=2.

Kenji Mohri, Yoko Onjo, Sung-Kil Yang

We study D-branes wrapping an exceptional four-cycle P(1,a,b) in a blown-up C^3/Z_m non-compact Calabi-Yau threefold with (m;a,b)=(3;1,1), (4;1,2) and (6;2,3). In applying the method of local mirror symmetry we find that the Picard-Fuchs equations for the local mirror periods in the Z_{3,4,6} orbifolds take the same form as the ones in the local E_{6,7,8} de

Y. Anusooya-Pati, Z. G. Soos, A. Painelli

Exact ground states, charge densities and excitation energies are found using valence bond methods for N-site modified Hubbard models with uniform spacing. At the neutral-ionic transition (NIT), the ground state has a symmetry crossover in 4n, 4n+2 rings with periodic and antiperiodic boundary conditions, respectively. The modified Hubbard model has a contin

Gil Paz

The radial momentum operator in quantum mechanics is usually obtained through canonical quantization of the (symmetrical form of the) classical radial momentum. We show that the well known connection between the Hamiltonian of a free particle and the radial momentum operator $\hat{H}=\hat{P}_{r}^2/2m+ $\hat{L}^2$}/2mr^{2}$ is true only in one or three dimens

A. Dedes, C. Hugonie, S. Moretti, K. Tamvakis

We study the phenomenology of a new Minimally-extended Supersymmetric Standard Model (nMSSM) where a gauge singlet superfield is added to the MSSM spectrum. The superpotential of this model contains no dimensionful parameters, thus solving the mu-problem of the MSSM. A global discrete R-symmetry, forbidding the cubic singlet self-interaction, imposed on the

Scott J. Kenyon, Rogier A. Windhorst

We investigate the constraints that Olbers Paradox, applied to the Zodiacal Background as measured from space, sets on outer solar system objects. If extended to very faint limits, R = 40--50 mag, the steep optical luminosity function (LF) of Kuiper Belt objects (KBOs) at R less than 26 mag implies an infinitely bright night sky. Small KBOs with radii of 1 m

David A. Kokorowski, Alex D. Cronin, Tony D. Roberts, David E. Pritchard

We measure the decoherence of a spatially separated atomic superposition due to spontaneous photon scattering. We observe a qualitative change in decoherence versus separation as the number of scattered photons increases, and verify quantitatively the decoherence rate constant in the many-photon limit. Our results illustrate an evolution of decoherence consi

Qun Wang, Chung-Wen Kao, Gouranga C. Nayak, Horst Stoecker

By using the background field method of QCD in a path integral approach, we derive the equation of motion for the classical chromofield and for the gluon in a system containing the gluon and the classical chromofield simultaneously. This inhomogeneous field equation contains a current term, which is the expectation value of a composite operator including lin

Marie-Noëlle Célérier

This paper is the third of a series dedicated to the study of the Delayed Big-Bang (DBB) class of inhomogeneous cosmological models of Lemaître-Tolman-Bondi type. In the first work, it was shown that the geometrical properties of the DBB model are such that the horizon problem can be solved, without need for any inflationary phase, for an observer situated s

Gil Paz

The non self-adjointness of the radial momentum operator has been noted before by several authors, but the various proofs are incorrect. We give a rigorous proof that the $n$-dimensional radial momentum operator is not self- adjoint and has no self-adjoint extensions. The main idea of the proof is to show that this operator is unitarily equivalent to the mom

M. Salle, J. Smit, J. C. Vink

Using a Hartree ensemble approximation, we investigate the dynamics of the \f^4 model in 1+1 dimensions. We find that the fields initially thermalize with a Bose-Einstein distribution for the fields. Gradually, however, the distribution changes towards classical equipartition. Using suitable initial conditions quantum thermalization is achieved much faster t

S. J. Smartt, P. A. Crowther, P. L. Dufton, D. J. Lennon

We present high quality spectroscopic data for two massive stars in the OB10 association of M31, OB10-64 (B0Ia) and OB10-WR1 (WC6). Medium resolution spectra of both stars were obtained using the ISIS spectrograph on the William Hershel Telescope. This is supplemented with HST-STIS UV spectroscopy and KeckI HIRES data for OB10-64. A non-LTE model atmosphere

Demosthenes Ellinas, Jiannis Pachos

We present a nonlocal construction of universal gates by means of holonomic (geometric) quantum teleportation. The effect of the errors from imperfect control of the classical parameters, the looping variation of which builds up holonomic gates, is investigated. Additionally, the influence of quantum decoherence on holonomic teleportation used as a computati

T. Scopigno, U. Balucani, G. Ruocco, F. Sette

New inelastic X-ray scattering experiments have been performed on liquid lithium in a wide wavevector range. With respect to the previous measurements, the instrumental resolution, improved up to 1.5 meV, allows to accurately investigate the dynamical processes determining the observed shape of the the dynamic structure factor, $S(Q,ω)$. A detailed analysis

S. Alexeyev, S. Mignemi

We show that the black hole solutions of the effective string theory action, where one-loop effects that couple the moduli to gravity via a Gauss-Bonnet term are taken into account, admit primary scalar hair. The requirement of absence of naked singularities imposes an upper bound on the scalar charges.

G. Eilam, F. Krauss, M. Lublinsky

We discuss the possibility that mass effects, beyond phase space, may have substantial influence on the direct determination of $V_{tq}$ in decays of top quarks. In principle, our results are valid both for singly produced top and for $t {\bar t}$ pair production. The mass effect is practically irrelevant for the extraction of $V_{tb}$ from Tevatron data, bu

D. Karevski, Y-C. Lin, H. Rieger, N. Kawashima

We study the critical behavior of Ising quantum magnets with broadly distributed random couplings (J), such that $P(\ln J) \sim |\ln J|^{-1-α}$, $α>1$, for large $|\ln J|$ (Lévy flight statistics). For sufficiently broad distributions, $α<α_c$, the critical behavior is controlled by a line of fixed points, where the critical exponents vary with the Lévy inde

B. P. Kosyakov

The holographic principle is represented as the well-known de Alfaro, Fubini and Furlan correspondence between the generating functional for the Green functions of the Euclidean quantum field theory in $D$ dimensions and the Gibbs average for the classical statistical mechanics in $D+1$ dimensions. This correspondence is used to explain the origin of quantum

Teparksorn Pengpan, Xiaozhen Xiong

We show that the noncommutative Wess-Zumino (NCWZ) Lagrangian with permutation terms in the interaction parts is renormalizable at one-loop level by only a wave function renormalization. When the non-commutativity vanishes, the logarithmic divergence of the wave function renormalization of the NCWZ theory is the same as that of the commutative one. Next the

Wung-Hong Huang

The renormalization of effective potential for the noncommutative scalar field theory is investigated to the two-loop approximation. It is seen that the nonplanar diagram does not appear in the one-loop potential. However, nonplanar diagram can become dominant in the two-loop level as the noncommutativity of geometry is sufficiently small. The result shows t

Michael Steiner, R. W. Rendell

Entanglement between particle and detector is known to be inherent in the measurement process. Gurvitz recently analyzed the coupling of an electron in a double dot (DD) to a quantum point contact (QPC) detector. In this paper we examine the dynamics of entanglement that result between the DD and QPC. The rate of entanglement is optimized as a function of co

Giacomo Ciaramicoli, Paolo Tombesi, David Vitali

We study the possible limitations and sources of decoherence in the scheme for the deterministic generation of polarization-entangled photons, recently proposed by Gheri et al. [K. M. Gheri et al., Phys. Rev. A 58, R2627 (1998)], based on an appropriately driven single atom trapped within an optical cavity. We consider in particular the effects of laser inte

Yong-Sheng Zhang, Chuan-Feng Li, Guang-Can Guo

In a recent paper [A. Cabello, Phys. Rev. A 61, 052312 (2000)], a quantum key distribution protocol based on entanglement swapping was proposed. However, in this comment, it is shown that this protocol is insecure if Eve use a special strategy to attack.

Z. Li, N. T. Folwell, T. O. Raubenheimer

In the JLC/NLC X-band linear collider, it is essential to reduce the long-range dipole wakefields in the accelerator structure to prevent beam break up (BBU) and emittance degradation. The two methods of reducing the long-range wakefields are detuning and damping. Detuning reduces the wakefields rapidly as the dipole modes de-cohere but, with a finite number

V. M. Shabaev

The quantum electrodynamic theory of the nuclear recoil effect in atoms to all orders in αZ and to first order in m/M is considered. The complete αZ - dependence formulas for the relativistic recoil corrections to the atomic energy levels are derived in a simple way. The results of numerical calculations of the recoil effect to all orders in αZ are presented

Vladimir G. Baryshevsky, Konstantin G. Batrakov

Effect of guiding magnetic field on evolution of stimulated emission is considered. It is shown that the transverse dynamics of electrons contributes to generation process and that contribution decreases with the magnetic field grows. The equation of generation for stimulated radiation of electron beam passing over periodic medium in magnetic field of arbitr

J. A. Lettry

Exotic beams of short-lived radioisotopes are produced in nuclear reactions such as thermal neutron induced fission, target or projectile fragmentation and fusion reactions. For a given radioactive ion beam (RIB), different production modes are in competition. For each of them the cross section, the intensity of the projectile beam and the target thickness d

Sangyong Jeon, Joseph Kapusta

We compare three semi-microscopic theories to the first data on particle production in central Au+Au collisions taken at RHIC by the PHOBOS collaboration as well as to existing data on central Pb+Pb collisions taken at the SPS by the NA49 collaboration. LEXUS represents the SPS data quite well but not the RHIC data, whereas the wounded nucleon model does the

Jiunn-Wei Chen, Thomas D. Cohen, Chung Wen Kao

Polarized beam gamma p Compton scattering provides a theoretically clean way to extract the isovector parity violating pion-nucleon coupling constant $h_{πNN}^{(1)}$. This channel is more tractable experimentally than the recently proposed extraction of $h_{πNN}^{(1)}$ from the Bedaque-Savage process --- polarized target gamma p compton scattering. The leadi

T. Gaitanos, H. H. Wolter, C. Fuchs

We analyze the thermodynamical state of nuclear matter in transport descriptions of heavy ion reactions. We determine thermodynamical variables from an analysis of local momentum space distributions and compare to blast model parameters from an analysis of fragment energy spectra. These descriptions are applied to spectator and fireball matter in semi-centra

T. Gaitanos, H. H. Wolter, C. Fuchs, A. Faessler

We discuss the problems involved in extracting the nuclear equation-of-state from heavy-ion collisions. We demonstrate that the equation of state becomes effectively softer in non-equilibrium and this effect is observable in terms of collective flow effects. Thus, non-equilibrium effects must be included in transport descriptions on the level of the effectiv

E. Pace, G. Salme`, S. Scopetta

The possibility to safely extract the neutron deep inelastic structure function $F_2^n(x)$ in the range $0 \le x \le 0.9$ from joint measurements of deep inelastic structure functions of $^{3}He$ and $^{3}H$ is demonstrated. While the nuclear structure effects are relevant, the model dependence in this extraction linked to the $N-N$ interaction is shown to b

G. M. Huber, G. J. Lolos, Z. Papandreou, J. Hovdebo

The (pi+,pd), and (pi+,dd) reactions were investigated with pions of 100 and 165 MeV kinetic energy on 6Li and 12C targets. In comparison with previously published (pi+,pp) data on the same targets and at the same beam energies, kinematic regions were identified in which the neutron pickup process n+p->d dominated the observed deuteron yield. The importance

Jean-Luc Thiffeault

We classify Lie-Poisson brackets that are formed from Lie algebra extensions. The problem is relevant because many physical systems owe their Hamiltonian structure to such brackets. A classification involves reducing all brackets to a set of normal forms, independent under coordinate transformations, and is achieved with the techniques of Lie algebra cohomol

Mark Adler, Pierre van Moerbeke

Matrix Fourier-like integrals over the classical groups O_+(n), O_-(n), Sp(n) and U(n) are connected with the distribution of the length of the longest increasing sequence in random permutations and random involutions and the spectrum of random matrices. One of the purposes of this paper is to show that all those integrals satisfy the Painlevé V equation wit

Etienne Blanchard, Ken Dykema

Given reduced amalgamated free products of C$^*$-algebras, $(A,phi)=*_i(A_i,phi_i)$ and $(D,psi)=*_i(D_i,psi_i)$, an embedding $A\to D$ is shown to exist assuming there are conditional expectation preserving embeddings $A_i\to D_i$. This result is extended to show the existance of the reduced amalgamated free product of certain classes of unital completely p

Allen Knutson

We prove two lemmata about Schubert calculus on generalized flag manifolds G/B, and in the case of the ordinary flag manifold GL_n/B we interpret them combinatorially in terms of descents, and geometrically in terms of missing subspaces. One of them gives a symmetry of Schubert calculus that we christen_descent-cycling_. Computer experiment shows that these

A. Koukkous, H. Guiol

We consider an asymmetric zero range process in infinite volume with zero mean and random jump rates starting from equilibrium. We investigate the large deviations from the hydrodynamical limit of the empirical distribution of particles and prove an upper and a lower bound for the large deviation principle. Our main argument is based on a super-exponential e

János Kollár

We prove that for every compact, connected, differentiable 3--manifold $M$ there is a compact complex manifold $X$ which can be obtained from projective 3--space by a sequence of smooth, real blow ups and downs such that $M$ is diffeomorphic to the set of real points of $X$. By earlier results, such an $X$ can almost never be projective.

Carlos Simpson

We give an explicit way of calculating the set of homotopy classes of morphisms from a Tamsamani n-category A to another one B. This calculation uses a Reedy-cofibrant cosimplicial resolution of A, using a new notion of ``free cofibration&#39;&#39; of n-precats. The free cofibrations of n-precats seem to be the analogue for n-categories of the Bousfield-Kan

Claude Cibils, Marc Rosso

We classify graded Hopf algebras structures over path coalgebras, that is over free pointed coalgebras, using Hopf quivers which are analogous to Cayley graphs. The description involves formulas for the product besides the canonical formulas for the coproduct. This makes explicit the quantum shuffle product making use of natural elements in a Hopf bimodule h

Aleksy Tralle

In this paper we show that a certain solvable Lie group constructed in a paper by Benson and Gordon has no lattices. This result answers (in the negative way) a question posed by several authors in the context of symplectic geometry. The main theorem is proved with the use of rational homotopy theory.

Torsten Ekedahl, Gerard van der Geer

We give upper and lower bounds for the order of the top Chern class of the Hodge bundle on the moduli space of principally polarized abelian varieties. We also give a generalization to higher genera of the famous formula $12 λ_1=δ$ for genus 1.

Markus Fulmek, Michael Kleber

We present a ``method&#39;&#39; for bijective proofs for determinant identities, which is based on translating determinants to Schur functions by the Jacobi--Trudi identity. We illustrate this ``method&#39;&#39; by generalizing a bijective construction (which was first used by Goulden) to a class of Schur function identities, from which we shall obtain bijec

Nguyen Ai Viet, Kameshwar C. Wali

We study the geometry of a two-sheeted space-time within the framework of non-commutative geometry. As a prelude to the Standard Model in curved space-time, we present a model of a left- and a right- chiral field living on the two sheeted-space time and construct the action functionals that describe their interactions.

D. V. Vassilevich, A. Zelnikov

We study discrete (duality) symmetries of functional determinants. An exact transformation of the effective action under the inversion of background fields $β(x) \to β^{-1}(x)$ is found. We show that in many cases this inversion does not change functional determinants. Explicitly studied models include a matrix theory in two dimensions, the dilaton-Maxwell t

Max Zucker

Using N=2 off-shell supergravity in five dimensions, we supersymmetrize the brane world scenario of Randall and Sundrum. We extend their construction to include supersymmetric matter at the fixpoints.

Yu. A. Sitenko

The problem of the axial anomaly in the presence of the Bohm-Aharonov gauge vector field is exactly solved.

Yu. A. Sitenko

A massless spinor field is quantized in the background of a singular static magnetic vortex in 2+1-dimensional space-time. The method of self-adjoint extensions is employed to define the most general set of physically acceptable boundary conditions at the location of the vortex. Under these conditions, the vacuum energy density and effective potential in the

Yu. A. Sitenko

Effects of the configuration of an external static magnetic field in the form of a singular vortex on the vacuum of a quantized massless spinor field are determined. The most general boundary conditions at the punctured singular point which make the twodimensional Dirac Hamiltonian to be self-adjoint are employed.

A. A. Deriglazov

Bosonic model inspired by D=11 superstring action is investigated. An appropriate set of variables is find, in which the light-cone quantization turns out to be possible. It is shown that anomaly terms in the algebra of the light-cone Poincare generators are absent for the case D=27.

Bo Feng, Yang-Hui He

In this short note, inspired by much recent activity centered around attempts to formulate various correspondences between the classification of affine SU(k) WZW modular-invariant partition functions and that of discrete finite subgroups of SU(k), we present a small and perhaps interesting observation in this light. In particular we show how the groups gener

Alfredo T. Suzuki, Alexandre G. M. Schmidt

The Coulomb gauge has at least two advantadges over other gauge choices in that bound states between quarks and studies of confinement are easier to understand in this gauge. However, perturbative calculations, namely Feynman loop integrations are not well-defined (there are the so-called energy integrals) even within the context of dimensional regularizatio

Ichiro Oda

We report the issues of localization of various bulk fields on a brane in a curved background from a local field-theoretic viewpoint where a special attention is paid to a warp geometry in a general space-time dimension. We point out that spin 0 scalar field and spin 2 graviton are naturally localized on a brane with the exponentially decreasing warp factor,

Kirill A. Kazakov

The relationship between the classical and quantum theories of gravity is reexamined. The value of the gravitational potential defined with the help of the two-particle scattering amplitudes is shown to be in disagreement with the classical result of General Relativity given by the Schwarzschild solution. It is shown also that the potential so defined fails

Karyn M. Apfeldorf, Horacio E. Camblong, Carlos R. Ordonez

The issue of field redefinition invariance of path integrals in quantum field theory is reexamined. A ``paradox&#39;&#39; is presented involving the reduction to an effective quantum-mechanical theory of a $(d+1)$-dimensional free scalar field in a Minkowskian spacetime with compactified spatial coordinates. The implementation of field redefinitions both bef

Philip R. Page

The colour, flavour, spin and J^PC of glueballs and hybrid mesons and baryons are constructed in an intuitive manner in both the gluon counting and adiabatic definitions. Glueball decay, production and mixing and hybrid meson decay selection rules and production are clarified.

V. Folomeev, V. Gurovich, R. Usupov

Now the hypothesis of existence of scalar fields of a various nature and energy density in the modern Universe is intensively explored. It can explain a nature of the dark (non- baryon) matter in the Universe and an existence of positive $Λ$-term (see e.g. gr-qc/9904398). One of component of such field has a cluster nature and organizes in the closed gravita

T. M. Aliev, M. K. Cakmak, M. Savci

The general analysis of lepton polarization asymmetries in rare B -> K^* l^+ l^- decay is investigated. Using the most general, model independent effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for l^- and l^+ and combinations of them are presented. The dependence of lepton polarizations and

M. Shifman

I review the notion of the quark-hadron duality from the modern perspective. Both, the theoretical foundation and practical applications are discussed. The proper theoretical framework in which the problem can be formulated and treated is Wilson&#39;s operator product expansion (OPE). Two models developed for the description of duality violations are conside

Adrian Kent

Recent papers by Busza et al. and Dar et al. have considered empirical bounds on the risk of producing a hypothetical stable negatively charged strangelet at the Brookhaven relativistic heavy ion collider (RHIC) experiments, and thereby destroying the Earth. We examine here ways in which these bounds could, hypothetically, be evaded. We find several,some of

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

We derive and analyze the Bethe-Salpeter equations for spin zero diquarks in the color superconducting phase of cold dense QCD with two massless flavors. The spectrum of diquarks contains an infinite number of massive excitations and five (nearly) massless pseudoscalars. The former are singlets while the latter include a doublet, an antidoublet and a singlet

M. Hirsch, W. Porod, J. Romao, J. W. F. Valle

The solar and atmospheric neutrino anomalies constitute the only solid and most remarkable evidence for physics beyond the Standard Model, indicating that the lepton mixing matrix is fundamentally distinct from that describing the quarks. Here I will report on how supersymmetry with spontaneously or bilinearly broken R Parity provides a predictive theory for

M. Hirsch, W. Porod, J. W. F. Valle, M. A. Diaz

Bilinear R-parity violation is a simple extension of the MSSM allowing for Majorana neutrino masses. One of the three neutrinos picks up mass by mixing with the neutralinos of the MSSM, while the other two neutrinos gain mass from 1-loop corrections. Once 1-loop corrections are carefully taken into account the model is able to explain solar and atmospheric n

M. M. Brisudova, L. Burakovsky, T. Goldman

Regge trajectories of quark-antiquark mesons can be well approximated for phenomenology purposes by a specific nonlinear form, reflecting that the flux tubes cannot be arbitrarily large, but break due to the effect of pair-production. If confirmed, this would imply that there is only a finite number of bound states on each trajectory, and consequently, an ex

M. M. Brisudova, L. Burakovsky, T. Goldman

Meson spectra can be well approximated by a specific form of a nonlinear Regge trajectory which is consistent with a finite number of bound states. This may have important consequencies for experiment, and may be a hint for the theory.

F. Karsch, M. G. Mustafa, M. H. Thoma

Temporal meson correlators and their spectral functions are calculated in the deconfined phase using the hard thermal loop resummation technique. The spectral functions exhibit strong medium effects coming from the hard thermal loop approximation for the quark propagator. The correlators, on the other hand, do not differ significantly from free correlators,

Kacper Zalewski

Bose-Einstein correlations are being exploited to obtain information about the structure of the sources of hadrons in multiple particle production processes. In this paper the principles of this approach are described and some of the controversies about their implementation are discussed.

A. Boehrer

New results on inclusive heavy quark production in gamma gamma collisions are presented. Charm and bottom production are investigated at LEP II energies by the experiments ALEPH, DELPHI, L3, and OPAL. The total and differential cross sections for charm quarks are measured. The contributions from the direct and single-resolved processes are separated and thei

G. Bossard, H. J. Drescher, N. N. Kalmykov, S. Ostapchenko

The purpose of this paper is twofold: first we want to introduce a new type of hadronic interaction model (NEXUS), which has a much more solid theoretical basis as, for example, presently used models like QGSJET and VENUS, and ensures therefore a much more reliable extrapolation towards high energies. Secondly, we want to promote an extensive air shower (EAS

A. A. Pankov, N. Paver

We quantitatively discuss the possibility of deriving model-independent constraints on the general four-fermion contact interaction couplings, from the currently available data on the two-fermion production processes $e^+e^-\toμ^+μ^-$, $b\bar{b}$ and $c\bar{c}$ with unpolarized initial beams. The method is essentially based on particular, simple, combination

Chris Michael

We review lattice QCD results for glueballs (including a discussion of mixing with scalar mesons), hybrid mesons and exotic mesons (such as $B_s B_s$ molecules). We also discuss string breaking as a mixing between colour flux states and $B \bar{B}$ states.

Kacper Zalewski

The GGLP approach to Bose-Einstein correlations, a hydrodynamic model and a string model are briefly reviewed. The implications of the two models for the Bose-Einstein correlations among the decay products of a pair of W bosons are presented.

Y. Yamada, H. Eberl, K. Hidaka, S. Kraml

The O(alpha_s) SUSY QCD corrections to the decays of the MSSM Higgs bosons into bottom quarks and squarks can be very large for large tan beta in the on--shell renormalization scheme. We improve the calculation by a careful choice of the tree-level Higgs boson couplings in terms of running parameters of quarks and squarks.