December 1997 arXiv papers — page 6

M. Stebelski, M. Lisowski, E. Zipper

Quantum coherence of electrons interacting via the magnetostatic coupling and confined to a mesoscopic cylinder is discussed. The electromagnetic response of a system is studied. It is shown that the electromagnetic kernel has finite low frequency limit what implies infinite conductivity. It means that part of the electrons is in a coherent state and the sys

Alberto Pimpinelli

The morphological stability of two-dimensional islands nucleated on a substrate during vacuum or vapour-phase atom deposition is investigated. Using simple scaling arguments, it is shown that, contrary to expectation, dendritic islands may be converted into compact ones by increasing the deposition rate, provided that the size of the critical nucleus is larg

D. Rainer, H. Burkhardt, M. Fogelstrom, J. A. Sauls

A characteristic feature of the BCS theory of superconductivity is the quantum-mechanical coherence of particle and hole states. Direct observation of particle-hole coherence in unusual superconducting materials is a strong indication of traditional superconductivity. We use the Fermi liquid theory of superconductivity to study the implications of particle-h

Zhigang Zheng, Bambi Hu, Gang Hu

The spatiotemporal dynamics of a damped sine-Gordon chain with sinusoidal nearest-neighbor couplings driven by a constant uniform force are discussed. The velocity characteristics of the chain versus the external force is shown. Dynamics in the high- and low-velocity regimes are investigated. It is found that in the high-velocity regime, the dynamics is domi

Alexander D. Mirlin

This is an extended version of the talk given by the author at the NATO Advanced Study Institute "Supersymmetry and Trace Formulae" (Isaac Newton Institute, Cambridge, UK, 8-19 Septemebr 1997). Contains the following sections: 1. Eigenfunction correlations in the weak localization regime. 2. Strong correlations of eigenfunctions and level repulsion a

Edward W. Olszewski

We discuss the quality of kinematic data in dwarf spheroidal galaxies, the current interpretations of those data, and prospects for actually deriving the mass profile in these galaxies. We then discuss stellar populations constraints on some of the models that attempt to explain the kinematics and formation of the dSph's.

T. M. Brown, R. Kotak, S. D. Horner, E. J. Kennelly

Spectroscopic observations of 51 Pegasi and tau Bootis show no periodic changes in the shapes of their line profiles; these results for 51 Peg are in significant conflict with those reported by Gray and Hatzes (1997). Our detection limits are small enough to rule out nonradial pulsations as the cause of the variability in tau Boo, but not in 51 Peg. The abse

A. Comastri, W. N. Brandt, K. M. Leighly, F. Fiore

Results are presented for the first year of observations of a selected sample of Narrow-Line Seyfert 1 galaxies (Ton S 180, RE J1034+396, Ark 564) obtained with the imaging instruments onboard BeppoSAX. These are the first simultaneous broad band (0.1--10 keV) spectra so far obtained for this class of objects.

Frederick K. Lamb, M. Coleman Miller, Dimitrios Psaltis

The frequencies of the highest-frequency kilohertz QPOs recently discovered in some sixteen neutron stars in low-mass X-ray binary systems are most likely orbital frequencies. If so, these QPOs provide tight upper bounds on the masses and radii of these neutron stars and interesting new constraints on the equation of state of neutron star matter. If the freq

Tereasa G. Brainerd, Ian Smail

The angular clustering of faint field galaxies is investigated using deep imaging (I~25) obtained with the 10-m Keck-I telescope. The autocorrelation function is consistent with w(theta) ~ theta^-0.8 and, although less steep correlation functions cannot be ruled out with high confidence, we find no compelling evidence for a systematic decrease in the power l

Ulisse Munari, Giovanni Carraro, Roberto Barbon

UBVRI CCD photometry of a $2.^{\prime}1 \times 3.^{\prime}3$ field centered on the young open cluster Haffner~18 is presented and discussed. Spectroscopic classification of seven stars is also provided. 44 clusters members are identified, the earliest type being O6. The distance to the cluster is found to be 6.3 kpc, corresponding to a galactocentric distanc

Astrid Orr, A. N. Parmar, T. Yaqoob, M. Guainazzi

The combination of the broad band coverage and moderate spectral resolution of the LECS and MECS instruments on-board BeppoSAX allow the spectra of AGN to be studied in unprecedented detail down to 0.1 keV. We describe the calibration and the performance of the LECS and report on observations of low-energy absorption features in the spectra of both a low (MC

C. O. Escobar, P. L. Da Silva, R. A. Vázquez

The potentiality of a Giant Shower Array to low energy gamma rays from gamma ray bursts is discussed. Effective areas are calculated for different scenarios and the results are encouraging. If gamma ray bursts have a spectrum which continues in the high energy gamma ray region, the Pierre Auger Observatory will be able to detect it.

J. J. M. in 't Zand, F. Verbunt, J. Heise, J. M. Muller

Two type I X-ray bursts were detected from a position consistent with the transient X-ray source in NGC 6652 with the Wide Field Camera of the BeppoSAX satellite, strongly suggesting that this transient is a neutron star. Our detection brings to ten the number of X-ray sources in globular clusters in which a type I X-ray burst has been seen, out of twelve kn

L. S. Nazarova, P. T. O'Brien, M. J. Ward, P. M. Gondhalekar

We present photoionization models of the high excitation gas in the Extended Narrow Line Region (ENLR) of NGC1068. The ENLR line fluxes have been calculated allowing for attenuation of the central-source ionizing continuum as a function of distance from the centre. Diffuse continuum emission from low density ENLR gas is included as an important secondary sou

Karl Glazebrook, Roberto Abraham, Basilio Santiago, Richard Ellis

The excess numbers of blue galaxies at faint magnitudes is a subject of much controversy. Recent Hubble Space Telescope results has revealed a plethora of galaxies with peculiar morphologies tentatively identified as the evolving population. We report the results of optical spectroscopy and near-infrared photometry of a sample of faint \HST galaxies from the

Maxim Braverman

We obtain estimates on the character of the cohomology of an $S^1$-equivariant holomorphic vector bundle over a Kaehler manifold $M$ in terms of the cohomology of the Lerman symplectic cuts and the symplectic reduction of $M$. In particular, we prove and extend inequalities conjectured by Wu and Zhang. The proof is based on constructing a flat family of comp

Jean-Paul Brasselet, Andrzej Weber

There are several ways to generalize characteristic classes for singular algebraic varieties. The simplest ones to describe are Chern-Mather classes obtained by Nash blow up. They serve as an ingredient to construct Chern-MacPherson-Schwartz classes. Unfortunately, they all are defined in homology. There are examples showing, that they do not lie in the imag

Alexander Polishchuk

In this paper we define a Poisson structure on some moduli spaces related to principal G-bundles on elliptic curves, the simplest example being the moduli space of stable pairs: a vector bundle and its global section. We also study birational morphisms between projective spaces appearing as such moduli spaces.

Alexander Polishchuk

In this paper we construct a projective action of certain arithmetic group on the derived category of coherent sheaves on an abelian scheme $A$, which is analogous to Weil representation of the symplectic group. More precisely, the arithmetic group in question is a congruence subgroup in the group of "symplectic" automorphisms of $A\times\hat{A}$ whe

B. C. Allanach, G. K. Leontaris, S. T. Petcov

It is shown that the hybrid MSW + VO solution of the solar neutrino problem, according to which the solar nu_e undergo matter-enhanced transitions into nu_mu, nu_tau in the Sun followed by long wave length (about 1.5 10^8 km) nu_e -> nu_mu, nu_tau oscillations in vacuum between the Sun and the Earth, can occur naturally in string-motivated grand unified theo

Enrique Gaztanaga, Pablo Fosalba

In Part I of this series, we introduced the Spherical Collapse (SC) approximation in Lagrangian space as a way of estimating the cumulants $ξ_J$ of density fluctuations in cosmological Perturbation Theory (PT). Within this approximation, the dynamics is decoupled from the statistics of the initial conditions, so we are able to present here the cumulants for

Michel Casse, Keith A. Olive, Elisabeth Vangioni-Flam, Jean Audouze

The flood of new data on deep surveys, and above all the CFRS (Canada-France-Redshift-Survey), has had a great impact on studies of galactic evolution. On the basis of cosmological models consistent with the improved values of the Hubble parameter, different star formation histories are tested against the observed UV, B and IR broad band comoving luminosity

C. P. Bachas, M. B. Green

The occupied and unoccupied fermionic BPS quantum states of a type-IIA string stretched between a D6-brane and an orthogonal D2-brane are described in M-theory by two particular holomorphic curves embedded in a Kaluza-Klein monopole. The absence of multiply-occupied fermionic states --- the Pauli exclusion principle --- is manifested in M-theory by the absen

Eugene H. Kim

The conductivity sum rule for a one-band hopping model relates the integrated spectral weight of the real part of the conductivity to the average kinetic energy. For such a model, the superconducting penetration depth is therefore dependent upon both the change in the conductivity spectral weight and the change in kinetic energy between the normal and superc

A. Recknagel, V. Schomerus

We discuss D-branes from a conformal field theory point of view. In this approach, branes are described by boundary states providing sources for closed string modes, independently of classical notions. The boundary states must satisfy constraints which fall into two classes: The first consists of gluing conditions between left- and right-moving Virasoro or f

Markus Grassl, Martin Roetteler, Thomas Beth

We investigate means to describe the non-local properties of quantum systems and to test if two quantum systems are locally equivalent. For this we consider quantum systems that consist of several subsystems, especially multiple qubits. We compute invariant polynomials, i. e., polynomial functions of the entries of the density operator which are invariant un

Stefan Giller, Piotr Milczarski

It is shown that a change of variable in 1-dim Schroedinger equation applied to the Borel summable fundamental solutions [Giller] is equivalent to Borel resummation of the fundamental solutions multiplied by suitably chosen $\hbar$-dependent constant. This explains why change of variable can improve JWKB formulae [Giller, Milczarski]. It is shown also that a

W. M. Alberico, M. B. Barbaro, S. M. Bilenky, J. A. Caballero

We calculate the ratio of proton and neutron yields in NC induced neutrino(antineutrino)-nucleus inelastic scattering at neutrino energies of about 1 GeV. We show that this ratio depends very weakly on the nuclear models employed and that in the neutrino and antineutrino cases the ratios have different sensitivity to the axial and vector strange form factors

M. Jezabek, P. Urban

Analytic formulae for the one-loop order QCD corrections to the differential width of the semileptonic b decay are given with the tau polarization taken into account. Thence the polarization of tau is expressed by its energy and the invariant mass of the tau + antineutrino system. The non-perturbative corrections by Falk et al. are incorporated in the calcul

Stephen M. Merkowitz

A spherical gravitational wave antenna is distinct from other types of gravitational wave antennas in that only a single detector is necessary to determine the direction and polarization of a gravitational wave. Zhou and Michelson showed that the inverse problem can be solved using the maximum likelihood method if the detector outputs are independent and hav

Michael B. Mensky

It is shown how the technique of restricted path integrals (RPI) or quantum corridors (QC) may be applied for the analysis of relativistic measurements. Then this technique is used to clarify the physical nature of thermal effects as seen by an accelerated observer in Minkowski space-time (Unruh effect) and by a far observer in the field of a black hole (Haw

Isao Kishimoto, Naoki Sasakura

We discuss the BPS configurations of IIB strings in the 7-brane background from M-theory viewpoint. We first obtain the hyperkahler geometry background of M-theory expected from the 7-brane solutions of the type IIB supergravity. We choose the appropriate complex structures of the background geometries and embed a membrane of M-theory holomorphically to obta

L. M. Kurdadze, Z. K. Silagadze

Some semileptonic weak decays of vector mesons are considered in the framework of the most popular quark models. The predicted branching ratios are unfortunately too small to make a study of these decays realistic at meson factories under construction.

N. D. Hari Dass, B. Sathiapalan

We study a configuration of a parallel F- (fundamental) and D- string in IIB string theory by considering its T-dual configuration in the matrix model description of M-theory. We show that certain non-perturbative features of string theory such as $O(e^{-\frac{1}{g_{s}}})$ effects due to soliton loops, the existence of bound state (1,1) strings and manifest

Hal Tasaki

This is a self-contained review about ferromagnetism in the Hubbard model, which should be accessible to readers with various backgrounds who are new to the field. We describe Nagaoka's ferromagnetism and flat-band ferromagnetism in detail, giving all necessary backgrounds as well as complete (but elementary) mathematical proofs. By studying an intermedi

M. H. S. Amin, Ian Affleck, M. Franz

We study the effect of the superconducting gap nodes on the vortex lattice properties of high temperature superconductors at very low temperatures. The nonlinear, nonlocal and nonanalytic nature of this effect is shown to have measurable consequences for the vortex lattice geometry and the effective penetration depth in the mixed state as measured by muon-sp

C. R. Gattringer, S. Jaimungal, G. W. Semenoff

We show how to obtain the dual of any lattice model with inhomogeneous local interactions based on an arbitrary Abelian group in any dimension and on lattices with arbitrary topology. It is shown that in general the dual theory contains disorder loops on the generators of the cohomology group of a particular dimension. An explicit construction for altering t

Seiji Terashima

We study the moduli space of vacua of four dimensional N=1 and N=2 supersymmetric gauge theories with the gauge groups $Sp(2 N_c)$, $SO(2 N_c)$ and $SO(2 N_c +1)$ using the M theory fivebrane. Higgs branches of the N=2 supersymmetric gauge theories are interpreted in terms of the M theory fivebrane and the type IIA $s$-rule is realized in it. In particular w

Andrew Gray

A new formulation of quantum mechanics is developed which does not require the concept of the wave-particle duality. Rather than assigning probabilities to outcomes, probabilities are instead assigned to entire fine-grained histories. The formulation is fully relativistic and applicable to multi-particle systems. It shall be shown that this new formulation m

H. Aratyn, E. Nissimov, S. Pacheva

A new infinite set of commuting additional (``ghost'') symmetries is proposed for the KP-type integrable hierarchy. These symmetries allow for a Lax representation in which they are realized as standard isospectral flows. This gives rise to a new double-KP hierarchy embedding ``ghost'' and original KP-type Lax hierarchies connected to each ot

Jiin-Chang Shaw, Ming-Hsien Tu

We study the gauge transformations between the supersymmetric AKNS (sAKNS) and supersymmetric two-boson (sTB) hierarchies. The Hamiltonian nature of these gauge transformations is investigated, which turns out to be canonical. We also obtain the Darboux-Backlund transformations for the sAKNS hierarchy from these gauge transformations.

Mariusz Dudek, Stefan Giller, Piotr Milczarski

We discuss a finite rectangular well as a perturbation for the infinite one with a depth $λ^2$ of the former as a perturbation parameter. In particular we consider a behaviour of energy levels in the well as functions of complex $λ$. It is found that all the levels of the same parity are defined on infinitely sheeted Riemann surfaces which topological struct

A. Bohm, H. Kaldass, P. Patuleanu

Intrinsic microphysical irreversibility is the time asymmetry observed in exponentially decaying states. It is described by the semigroup generated by the Hamiltonian $\QTR{it}{H}$ of the quantum physical system, not by the semigroup generated by a Liouvillian $\QTR{it}{L}$ which describes the irreversibility due to the influence of an external reservoir or

Stavros Garoufalidis, Jerome Levine

The goal of the present paper is to find higher genus surgery formulae for the set of finite-type invariants of homology spheres, and to develop a companion theory of finite-type invariants to be applied, in a subsequent publication, to the study of subgroups of the mapping class group. The main result is to show that six filtrations on the vector space gene

U. Mueller, M. Braun, R. Reichle, R. F. Salzgeber

We investigated the vibrational energies in the 2p^2A^"_2 and 3d^2E^" states of the triatomic deuterium molecule D_3. The experiments were performed using a fast neutral beam photoionization spectrometer recently developed at Freiburg. A depletion type optical double-resonance scheme using two pulsed dye lasers was applied. The measured vibrational f

C. N. De Marzo

The longitudinal development and other characteristics of the EECR induced atmospheric showers can be studied from space by detecting the fluorescence light induced in the atmospheric nitrogen. According to the Airwatch concept a single fast detector can be used for measuring both intensity and time development of the streak of fluorescence light produced by

N. H. Brook

The progress towards the realisation of the LHC-B Ring Imaging Cherenkov detector is reported.

P. T. Leung, Y. T. Liu, W. M. Suen, C. Y. Tam

Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is

David A. Brown, Pawel Danielewicz

We develop the new method of optimized discretization for imaging the relative source from two particle correlation functions. In this method, the source resolution depends on the relative particle separation and is adjusted to available data and their errors. We test the method by restoring assumed pp sources and then apply the method to pp and IMF data. In

E. Caurier, F. Didierjean, F. Nowacki, G. Walter

Allowed $β^+$ branches of very proton-rich $fp$ shell $Tz=-2$ nuclei at the proton drip-line are calculated in the full fp valence space. The $β^+$ decay half-lives calculated with the standard quenching factor ($g^{eff}_{A}/g_{A}$)=0.74 are in good agreement with existing experimental data. Detailed branching Gamow-Teller strength are predicted but comparis

S. B. Gerasimov

The cross section of the reaction $pp \to pp γγ$ is estimated and the exploration possibilities of this reaction to probe for a possible excitation of subnuclear degrees of freedom in two-nucleon systems, in particular, the production and decay of the NN-decoupled dibaryon resonances, are briefly discussed.Some arguments for and implications of the intermedi

Hideki Madokoro, Masayuki Matsuzaki

Relativistic Mean Field Theory is applied to the description of rotating nuclei. Since the previous formulation of Munich group was based on a special relativistic transformation property of the spinor fields, we reformulate in a fully covariant manner using tetrad formalism. The numerical calculations are performed for 3 zinc isotopes, including the newly d

K. Riisager

The increase at low energy of the S-factor for the 16O(p,gamma)17F* reaction claimed by Morlock et al. to be a new observation is well documented and explained in the literature.

Antoine Chambert-Loir

This is the text of a talk to the study week on \emph{Modular forms and Galois representations} held in Luminy, 1997. We give a survey of $p$-adic modular forms, as developped by Serre, Katz, Hida, Wiles, Coleman and others...

Antoine Chambert-Loir

Nous proposons dans ce texte une théorie des périodes $p$-adiques pour des schémas en groupes finis et plats. Nous utilisons pour ce faire la théorie de Dieudonné cristalline de Berthelot, Breen et Messing, ainsi que l'interprétation cristalline des anneaux de Fontaine. ----- We propose in this paper a theory of $p$-adic periods for finite flat group sch

Alfred S. Goldhaber

Intrinsically stable or `fundamental' solitons may be decorated with conserved charges which are pieces of those carried by elementary particles in the same medium. These `hairs' are always significant in principle, and in the strong-coupling regime (where solitons and particles exchange roles) may become major factors in dynamics.

Stanislaw D. Glazek

We outline a method of deriving boost invariant hamiltonians for effective particles in quantum field theory. The hamiltonians are defined and calculated using creation and annihilation operators in light-front dynamics. The renormalization group equations are written for a sequence of unitary transformations which gradually transform the bare canonical crea

Zheng Yin

We review brane engineering of mirror pairs of 3d N=4 theories. It reveals aspects of 3d physics not known from previous field theoretic studies: novel QFT's without Lagrangian description and transitions to them from conventional QFT's.

Raimar Wulkenhaar

We investigate the (noncommutative) geometry defined by the standard model, which turns out to be of Kaluza-Klein type. We find that spacetime points are replaced by extended two-dimensional objects which resemble the surface of a gyro. Their size is of the order of the inverse top quark mass.

Klaus Junemann, Olaf Lechtenfeld

We compute the BRST cohomology of the holomorphic part of the N=2 string at arbitrary ghost and picture number. We confirm the expectation that the relative cohomology at non-zero momentum consists of a single massless state in each picture. The absolute cohomology is obtained by an independent method based on homological algebra. For vanishing momentum, the

M. Quandt, H. Reinhardt

We consider Yang-Mills theory in a general class of Abelian gauges. Exploiting the residual Abelian symmetry on a quantum level, we derive a set of Ward identities in functional form, valid to all orders in perturbation theory. As a consequence, the coupling constant is only renormalised through the Abelian two-point function. This implies that asymptotic fr

Gordon Chalmers

We re-examine the threshold bound state problem on the wrong sign Taub-Nut space; the metric on which describes the relative moduli space of well separated BPS monopoles. The quantum mechanics gives rise to a continuous family of threshold bound states, in distinction to the unique one found on the Atiyah-Hitchin metric.

C. Weiss, K. Goeke

We calculate the isosinglet unpolarized quark-- and antiquark distributions at a low normalization point in the large--$N_c$ limit. The nucleon is described as a self-consistent soliton solution of the effective chiral theory. The ultraviolet cutoff is implemented by a Pauli-Villars subtraction. The quark and antiquark distributions satisfy the momentum as w

N. G. Deshpande, B. Dutta, Sechul Oh

We consider two body decays of B meson into a light vector (V) and a pseudoscalar (P) meson. The constraint obtained from the $B\to P P$ modes on the parameter space of the input parameters is imposed also on $B\to V P$ modes. In particular we constrain $ξ\equiv (1/N_c)$ for those modes from recently measured $B\to ωK, ϕK$ and are able to get a satisfactory

John Ellis

After a brief review of the Big Issues in particle physics, we discuss the contributions to resolving that could be made by various planned and proposed future colliders. These include future runs of LEP and the Fermilab Tevatron collider, B factories, RHIC, the LHC, a linear electron-positron collider, an electron-proton collider in the LEP/LHC tunnel, a mu

T. Barreiro, B. de Carlos, E. J. Copeland

We present the results of a detailed investigation into the consequences of adding specific string motivated non-perturbative corrections to the usual tree level Kahler potential in dilaton dominated scenarios. The success of the model is judged through our ability to obtain a realistic VEV for the dilaton < Re S > ~ 2, corresponding to the true minima of th

Stefano Catani

The following topics in perturbative QCD are reviewed: recent theoretical progress in higher-order calculations; soft-gluon resummation for hard-scattering processes at large $E_T$ and high $x$; low-$x$ behaviour of structure functions and recent theoretical results on BFKL dynamics; infrared renormalons and power corrections to perturbative predictions; upd

M. K. Samal

The determination of CP violating phases in the Majorana neutrino mixing matrix using phenomenological constraints from neutrino oscillations, neutrinoless double beta decay, ($μ^-, e^+$) conversion and few other processes is discussed. We give the expressions for the phases in terms of the mixing angles and masses consistent with the recent data from Kamiok

Jan Stern

We review some theoretical and phenomenological aspects of the scenario in which the spontaneous breaking of chiral symmetry is not triggered by a formation of a large condensate <\bar{q} q>. Emphasis is put on the resulting pattern of light quark masses, on the constraints arising from QCD sum rules and on forthcoming experimental tests.

M. G. Ryskin, Yu. M. Shabelski

The backgrounds due to the direct diffractive dissociation of the photon into the $π^+π^-$ as well as $K^+K^-$ pairs to the &#34;elastic&#34; diffractive $ρ&#39;$ and $ϕ$ mesons production in electron-proton collisions are calculated. It is shown that the role of background and background-resonant interference contributions is very important in experimental

HM Chan, ST Tsou

The Dualized Standard Model offers a natural place both to Higgs fields and to fermion generations with Higgs fields appearing as frame vectors in internal symmetry space and generation appearing as dual colour. If they are assigned those niches, it follows that there are exactly 3 generations of fermions, and that at the tree-level, only one generation has

Tord Riemann

The Z line shape is measured at LEP with an accuracy at the per mille level. Usually it is described in the Standard Model of electroweak interactions with account of quantum corrections. Alternatively, one may attempt different model-independent approaches in order to extract quantities like mass and width of the Z boson. If a fit deviates from that in the

T. Kobayashi, Z. Z. Xing

Four simple but realistic patterns of quark mass matrices are derived from orbifold models of superstring theory in the absence of gauge symmetries. Two of them correspond to the Ramond-Roberts-Ross types, which have five texture zeros in up and down quark sectors. The other two, with four texture zeros, preserve the structural parallelism between up and dow

G. Holzwarth

In the standard $R^4$ embedding of the chiral O(4) model in 3+1 dimensions the winding number is not conserved near the chiral phase transition and thus no longer can be identified with baryon number. In order to reestablish conserved baryon number in effective low-energy models near and above the critical temperature $T_c$ it is argued that insisting in O(N

Luis M. A. Bettencourt, Christof Wetterich

We investigate the non-equilibrium properties of an N-component scalar field theory. The time evolution of the correlation functions for an arbitrary ensemble of initial conditions is described by an exact functional differential equation. In leading order in the 1/N expansion the system can be understood in terms of infinitely many conserved quantities. The

R. D. Peccei

After outlining some of the issues surrounding the flavor problem, I present three speculative ideas on the origin of families. In turn, families are conjectured to arise from an underlying preon dynamics; from random dynamics at very short distances; or as a result of compactification in higher-dimensional theories. Examples and limitations of each of these

Jing-Ling Chen, Mo-Lin Ge, Xue-Qian Li, Yong Liu

The relation between CP-violation phase angle and the other three mixing angles in Cabibbo-Kobayashi-Maskawa matrix is postulated. This relation has a very definite geometry meaning. The numerical result coincides surprisingly with that extracting from the experiments. It can be further put to the more precise tests in the future.

N. E. Ligterink, N. R. Walet, R. F. Bishop

We apply the coupled cluster method (CCM) to the Hamiltonian version of the latticised O(4) non-linear sigma model. The method, which was initially developed for the accurate description of quantum many-body systems, gives rise to two distinct approximation schemes. These approaches are compared with each other as well as with some other Hamiltonian approach

SESAM, TXL collaboration, :, Th. Lippert

We investigate the critical dynamics of the Hybrid Monte Carlo algorithm approaching the chiral limit of standard Wilson fermions. Our observations are based on time series of lengths O(5000) for a variety of observables. The lattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and kappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55.

Thomas Lippert

The Hybrid Monte Carlo (HMC) algorithm currently is the favorite scheme to simulate quantum chromodynamics including dynamical fermions. In this talk-which is intended for a non-expert audience--I want to bring together methodical and practical aspects of the HMC for full QCD simulations. I will comment on its merits and shortcomings, touch recent improvemen

Stefano Bianco

Physics at DAFNE, the new Frascati e+e- machine, is reviewed, as well as the esperiments: DEAR - search for KN exotic atoms, FINUDA - spectroscopy and decays of hypernuclei, and KLOE - a multipurpose detector designed for measuring direct CP violation in the K system.

M. K. Suleimanov, O. B. Abdinov, A. I. Anoshin, A. M. Bagirov

New experimental data on the behaviour of the single-particle two-dimensional correlation functions R versus Q (Q is the number of nucleons emitted from nuc- lei) and Ap (Ap is the mass of projectile nuclei) are presented in this paper. The interactions of protons, d, 4He and 12C nuclei with carbon nuclei (at a momentum of 4.2 A GeV/c) are considered.The val

E. Frlez, D. Pocanic, K. A. Assamagan, J. P. Chen

We have measured pion single charge exchange differential cross sections on the proton at 27.5 MeV incident $π^-$ kinetic energy in the center of momentum angular range between $0^\circ$ and $55^\circ$. The extracted cross sections are compared with predictions of the standard pion-nucleon partial wave analysis and found to be in excellent agreement.

A. Barros, C. Romero

It is shown that in the weak field approximation solutions of Brans-Dicke equations are simply related to the solutions of General Relativity equations for the same matter distribution. A simple method is developed which permits to obtain Brans-Dicke solutions from Einstein solutions when both theories are considered in their linearized forms. To illustrate

Ruy Exel, Marcelo Laca, John Quigg

A collection of partial isometries whose range and initial projections satisfy a specified set of conditions often gives rise to a partial representation of a group. The C*-algebra generated by the partial isometries is thus a quotient of the universal C*-algebra for partial representations of the group, from which it inherits a crossed product structure, of

L. Cooper, I. I. Kogan, A. Lopez, R. J. Szabo

It is shown that the Jain mapping between states of integer and fractional quantum Hall systems can be described dynamically as a perturbative renormalization of an effective Chern-Simons field theory. The effects of mirror duality symmetries of toroidally compactified string theory on this system are studied and it is shown that, when the gauge group is com

Eric Cockayne, Karin M. Rabe

We use first-principles density-functional total energy and polarization calculations to calculate the piezoelectric tensor at zero temperature for both cubic and simple tetragonal ordered supercells of Pb_3GeTe_4. The largest piezoelectric coefficient for the tetragonal configuration is enhanced by a factor of about three with respect to that of the cubic c

Adolfo G. Eguiluz, Wolf-Dieter Schoene

Theoretical descriptions of the spectrum of electronic excitations in real metals have not yet reached a fully predictive, &#34;first-principles&#34; stage. In this paper we begin by presenting brief highlights of recent progress made in the evaluation of dynamical electronic response in metals. A comparison between calculated and measured spectra - we use t

S. Yu. Ezhov, V. I. Anisimov, H. F. Pen, D. I. Khomskii

We present a band structure study of orbital polarization and ordering in the two-dimensional triangular lattice transition metal compounds LiVO_2 and NaTiO_2. It is found that while in NaTiO_2 the degeneracy of t_{2g} orbitals is lifted due to the trigonal symmetry of the crystal and the strong on cite Coulomb interaction, in LiVO_2 orbital degeneracy remai

Allan I. Solomon, Karol A. Penson

We consider the Hubbard model and its extensions on bipartite lattices. We define a dynamical group based on the $η$-pairing operators introduced by C.N.Yang, and define coherent pairing states, which are combinations of eigenfunctions of $η$-operators. These states permit exact calculations of numerous physical properties of the system, including energy, va

David Carpentier, Pierre Le Doussal

We study 2D solids with weak substrate disorder, using Coulomb gas renormalisation. The melting transition is found to be replaced by a sharp crossover between a high $T$ liquid with thermally induced dislocations, and a low $T$ glassy regime with disorder induced dislocations at scales larger than $ξ_{d}$ which we compute ($ξ_{d}\gg R_{c}\sim R_{a}$, the La

Per Frojdh, Martin Howard, Kent B. Lauritsen

We examine the effects of introducing a wall or edge into a directed percolation process. Scaling ansatzes are presented for the density and survival probability of a cluster in these geometries, and we make the connection to surface critical phenomena and field theory. The results of previous numerical work for a wall can thus be interpreted in terms of sur

Allan I. Solomon, Joseph L. Birman

A dynamical group for the single-particle (non-interacting) Quantum Hall Effect is found, and used to describe the Landau levels and determine the transverse (Hall) current.

Jeppe C. Dyre

This paper considers the problem of estimating the time auto-correlation function for a quantity that is defined in configuration space, given a knowledge of the mean-square displacement as function of time in configuration space. The problem is particularly relevant for viscous liquids, where the interesting time-scales are often beyond those reachable by c

S. Curnoe, P. C. E. Stamp

Quantum oscillation phenomena, in conventional 2-dimensional electron systems and in the fractional quantum Hall effect, are usually treated in the Lifshitz-Kosevich formalism. This is justified in three dimensions by Luttinger&#39;s expansion, in the parameter $omega_c/μ$. We show that in two dimensions this expansion breaks down, and derive a new expressio

Sudip Chakravarty, Lan Yin, Elihu Abrahams

We show that a non-Fermi liquid state of interacting electrons in two dimensions is stable in the presence of disorder and is a perfect conductor, provided the interactions are sufficiently strong. Otherwise, the disorder leads to localization as in the case of non-interacting electrons. This conclusion is established by examining the replica field theory in

Volkhard Buchholtz, Thorsten Poeschel

We investigate numerically the interaction of a stream of granular particles with a resting obstacle in two dimensions. For the case of high stream velocity we find that the force acting on the obstacle is proportional to the square of the stream velocity, the density and the obstacle size. This behavior is equivalent to that of non- interacting hard spheres

Kai Nagel, Dietrich E Wolf, Peter Wagner, Patrice Simon

Microscopic modeling of multi-lane traffic is usually done by applying heuristic lane changing rules, and often with unsatisfying results. Recently, a cellular automaton model for two-lane traffic was able to overcome some of these problems and to produce a correct density inversion at densities somewhat below the maximum flow density. In this paper, we summ

Michael Blank, Gerhard Keller

For piecewise expanding one-dimensional maps without periodic turning points we prove that isolated eigenvalues of small (random) perturbations of these maps are close to isolated eigenvalues of the unperturbed system. (Here ``eigenvalue&#39;&#39; means eigenvalue of the corresponding Perron-Frobenius operator acting on the space of functions of bounded vari