July 1998 arXiv papers — page 5

Marcus Richter, Thomas Schreiber

We study properties of the human electrocardiogram under the working hypothesis that fluctuations beyond the regular structure of single cardiac cycles are unpredictable. On this background we discuss the possibility to use the phase space embedding method for this kind of signal. In particular, the specific nature of the stochastic or high dimensional compo

John Feldmeier, W. N. Brandt, M. Elvis, A. C. Fabian

We have used the ASCA satellite to make the first X-ray spectra of Markarian 6, a bright Seyfert 1.5 galaxy with complex and variable permitted lines, an ionization cone, and remarkable radio structures. Our 0.6--9.5 keV spectra penetrate to the black hole core of this Seyfert and reveal heavy and complex intrinsic X-ray absorption. Both total covering and s

Yasuhiro Hashimoto, Augustus Oemler

We report the results of the evaluation of the ``concentration-density'' relation of galaxies in the local universe, taking advantage of the very large and homogeneous data set available from the Las Campanas Redshift Survey (Shectman et al. 1996). This data set consists of galaxies inhabiting the entire range of galactic environments, from the spars

R. Giovanelli, M. Haynes, W. Freudling, L. da Costa

The Tully-Fisher (Tully and Fisher 1977; TF) relation is applied to obtain peculiar velocities of field spirals galaxies and to calculate dipoles of the peculiar velocity field to cz ~ 8000 km/s. The field galaxy sample is spatially co-extensive with and completely independent on a cluster sample, for which dipole characteristics are given in a separate pape

Luis C. Ho

Many nearby galaxies contain optical signatures of nuclear activity in the form of LINER nuclei. LINERs may be the weakest and most common manifestation of the quasar phenomenon. The physical origin of this class of objects, however, has been ambiguous. I draw upon a number of recent observations to argue that a significant fraction of LINERs are low-luminos

M. S. Oey

Superbubbles that result from the stellar winds and supernovae of OB associations probably play a fundamental role in the structure and energetics of the ISM in star-forming galaxies. Their influence may also dominate the relationship between the different interstellar gas phases. How do superbubbles form and evolve? How do they affect the local and global I

E. Miyata, H. Tsunemi, K. Torii, K. Hashimotodani

We detected an X-ray compact source inside the Cygnus Loop during the observation project of the whole Cygnus Loop with the ASCA GIS. The source intensity is 0.11 c s$^{-1}$ for GIS and 0.15 c s$^{-1}$ for SIS, which is the strongest in the ASCA band. The X-ray spectra are well fitted by a power law spectrum of a photon index of \error{-2.1}{0.1} with neutra

Martin Pohl

Recently, data of taken with the OSSE experiment have been combined with scanning observations by TGRS and SMM to produce maps of the narrow Galactic 511 keV line emission (Purcell et al. 1997). A modelling of the combined data give evidence for three distinct features: the Galactic plane, a central bulge, and an extended emission region at positive latitude

Martin Pohl

Here is reviewed our current understanding of Galactic and extragalactic diffuse gamma-ray emission. The spectrum of the extragalactic gamma-ray background above 30 MeV can be well described by a power law with photon index s=2.1. In the 2-10 MeV range a preliminary analysis of COMPTEL data indicates a lower intensity than previously found, with no evidence

Ari Laor

The mass of massive black holes in quasar cores can be deduced using the typical velocities of Hb-emitting clouds in the Broad Line Region (BLR) and the size of this region. However, this estimate depends on various assumptions and is susceptible to large systematic errors. The Hb-deduced black hole mass in a sample of 14 bright quasars is found here to corr

Elizabeth Gasparim

Consider the blow up $π: \widetilde{X} \to X$ of a rational surface $X$ at a point. Let $\widetilde{V}$ be a holomorphic bundle over $\widetilde{X}$ whose restriction to the exceptional divisor equals ${\cal{O}(j) \oplus {\cal O}(-j)$ and define $V =(π_*\widetilde{V})^{\vee \vee}.$ Friedman and Morgan gave the following bounds for the second Chern classes $j

Sergey Gavrilets, Hai Li, Michael D. Vose

A classical view of speciation is that reproductive isolation arises as a by-product of genetic divergence. Here, individual-based simulations are used to evaluate whether the mechanisms implied by this view may result in rapid speciation if the only source of genetic divergence are mutation and random genetic drift. Distinctive features of the simulations a

Sergey Gavrilets

The metaphor of holey adaptive landscapes provides a pictorial representation of the process of speciation as a consequence of genetic divergence. In this metaphor, biological populations diverge along connected clusters of well-fit genotypes in a multidimensional adaptive landscape and become reproductively isolated species when they come to be on opposite

Zygmunt Lalak, Stefan Pokorski, Steven Thomas

In this paper we discuss compactifications of M-theory to four dimensions on X \times S^1/Z_2, in which nonstandard embeddings in the E_8 \times E_8 vacuum gauge bundle are considered. At the level of the effective field theory description of Horava and Witten, this provides a natural extension of well known results at weak coupling, to strongly coupled E_8

Qaisar Shafi, Zurab Tavartkiladze

The supersymmetric flipped $SU(6)\times U(1)$ gauge symmetry can arise through compactification of the ten dimensional $E_8\times E_8$ superstring theory. We show how realistic phenomenology can emerge from this theory by supplementing it with the symmetry ${\cal R}\times {\cal U}(1)$, where ${\cal R}$ denotes a discrete `R'-symmetry. The well-known doub

Ho-Meoyng Choi, Chueng-Ryong Ji

We investigate the form factors and decay rates for the semileptonic decays of the kaon($K_{l3})$ using the light-front quark model. The form factors $f_{\pm}(q^{2})$ are calculated in $q^{+}=0$ frame and analytically continued to the time-like region, $q^{2}>0$. Our numerical results for the physical observables, $f_{-}/f_{+}|_{q^{2}=m^{2}_{l}}=-0.38$, $λ_{

K. Golec-Biernat, A. D. Martin

We construct off-diagonal parton distributions defined on the interval 0 < X < 1 starting from the off-forward distributions defined by Ji. We emphasize the particular role played by the symmetry relations in the &#34;ERBL-like&#34; region. We find the evolution equations for the off-diagonal distributions which conserve these symmetries. We present numerica

J. -M. Chung, B. K. Chung

The three-loop effective potential of the massless O(N) $ϕ^4$ theory is calculated analytically using techniques of dimensional regularization. We see a complete agreement between our result and Jackiw&#39;s result obtained only up to two-loop order using a different regularization (cutoff regularization) method, but the same renormalization conditions. For

Tomoyuki Arakawa

We extend the results of Drinfeld on Drinfeld functor to the case l>n. We present the character of finite-dimensional representations of the Yangian Y(sl_n) in terms of the Kazhdan-Lusztig polynomials as a consequence.

J. Velkovska, C. R. Morton, R. L. McGrath, P. Chung

Fission fragment mass and angular distributions were measured from the ^{64}Ni+^{197}Au reaction at 418 MeV and 383 MeV incident energy. A detailed data analysis was performed, using the one-body dissipation theory implemented in the code HICOL. The effect of the window and the wall friction on the experimental observables was investigated. Friction stronger

Lu-Ming Duan, Guang-Can Guo

To make arbitrarily accurate quantum computation possible, practical realization of quantum computers will require suppressing noise in quantum memory and gate operations to make it below a threshold value. A scheme based on realistic quantum computer models is described for suppressing noise in quantum computation without the cost of stringent quantum compu

P. Bozek

Particle production in equilibrium and nonequilibrium quantum systems is calculated. The effects of the off-shell propagation of nucleons in medium on the particle production are discussed. Comparision to the semiclassical production rate is given.

Tatiana Bandman, Leonid Makar-Limanov

For an affine variety $S$ we consider the ring $AK(S),$ which is the intersection of the rings of constants of all locally-nilpotent derivations of the ring $\Cal {O}(S).$ We show that $AK(S\times\Bbb {C}^n)=AK(S)$ for a smooth affine surface $S$ with $H^2(S,\Bbb {Z})=\{0\}.$

Richard E. Borcherds

The main result of this paper describes the normalizer of a finite parabolic subgroup of a (possibly infinite) Coxeter group. We use this to compute the automorphism groups of some Lorentzian lattices and K3 surfaces.

Tarek Ibrahim, Pran Nath

An analysis of the electric dipole moment (EDM) of the neutron and of the leptons in the minimal supersymmetric standard model (MSSM) with the most general allowed set of CP violating phases without generational mixing is given. The analysis includes the contributions from the gluino, the chargino and the neutralino exchanges to the electric dipole operator,

Romuald A. Janik, Maciej A. Nowak, Gabor Papp, Ismail Zahed

We investigate the effects of several Abelian Aharonov-Bohm fluxes $ϕ$ on the Euclidean Dirac spectrum of light quarks in QCD with two colors. A quantitative change in the quark return probability is caused by the fluxes, resulting into a change of the spectral correlations. These changes are controlled by a universal function of $σ_L ϕ^2$ where $σ_L$ is the

Chang Soo Park, Sahng-Kyoon Yoo, D. K. Park, Dal-Ho Yoon

We have investigated the escape rate of the nanospin particle with a magnetic field applied along the easy axis. The model studied here is described by the Hamiltonian $\hat{\cal H} = K_1 \hat{S}_z^2 + K_2 \hat{S}_y^2 + gμ_b H \hat{S}_x $, $(K_1 > K_2 > 0)$ from which the escape rate is calculated within the semiclassical approximation. We have obtained a di

V. Melik-Alaverdian, N. E. Bonesteel

Variational Monte Carlo calculations of the quasielectron and quasihole excitation energies in the fractional quantum Hall effect have been carried out at filling fractions $ν=1/3$, 1/5, and 1/7. For the quasielectron both the trial wave function originally proposed by Laughlin and the composite fermion wave function proposed by Jain have been used. We find

Henrik Bruus, Karsten Flensberg

Using a hydrodynamic model of the electron fluid in a point contact geometry we show that localized plasmons are likely to exist near the constriction. We attempt to relate these plasmons with the recent experimental observation of deviations of the quantum point contact conductance from ideal integer quantization. As a function of temperature this deviation

Noah Brosch

I review the development of UV and EUV astronomy, covering the spectral range from 5 to 300 nm, with emphasis on sky surveys for discrete sources. I discuss studies which resulted in lists of sources observed by imaging and deliberately omit most spectroscopic studies. Technical issues, such as detector and telescope developments, are treated separately from

T. Usui, M. Saito, A. Tomita

We observationally study the current star formation activities of early type spiral galaxies. We construct a complete sample of 15 early type spirals having far-infrared (FIR) to optical B band luminosity ratios, L(FIR)/L(B), larger than the average of the type, and make their CCD imaging of the R and H-alpha bands. The equivalent widths of H-alpha emission

S. Albeverio, S. M. Fei, Y. P. Wang

A detailed study of an $S={1\over2}$ spin ladder model is given. The ladder consists of plaquettes formed by nearest neighbor rungs with all possible SU(2)-invariant interactions. For properly chosen coupling constants, the model is shown to be integrable in the sense that the quantum Yang-Baxter equation holds and one has an infinite number of conserved qua

G. Grunberg

Power corrections in QCD (both conventional and unconventional ones arising from the ultraviolet region) are discussed within the infrared finite coupling-dispersive approach. It is shown how power corrections in Minkowskian quantities can be derived from the corresponding ones in associated Euclidean quantities through analyticity, allowing a parametrizatio

Takuya Okabe

We develop a general theory of Fermi liquids to discuss the Kadowaki-Woods relation $A\propto γ^2$. We derive a formula for the ratio $A/γ^2$ which is expressed as a product of two dimensionless parameters $α$ and $F$, where $α$ represents a coupling constant for quasiparticle scattering and $F$ is a geometric factor determined by the shape of the Fermi surf

Gary A. Williams

The distribution of thermally excited vortex loops near a superfluid phase transition is calculated from a renormalized theory. The number density of loops with a given perimeter is found to change from exponential decay with increasing perimeter to algebraic decay as T_c is approached, in agreement with recent simulations of both cosmic strings and high-T_c

R. E. Lagos, A. C. M. Stein-Barana, G. G. Cabrera

We present a simple model for the doped compound $Nd_{2-y}Ce_{y}CuO_{4}$, in order to explain some recent experimental results on the latter. Within a Hartree-Fock context, we start from an impurity Anderson-like model and consider the magnetic splitting of the $Nd$-$4f$ ground state Kramers doublet due to exchange interactions with the ordered $Cu$ moments.

M. Avrigeanu, A. N. Antonov, H. Lenske, I. Stetcu

The real part of the optical potential for the nucleon-nucleus scattering at lower energies (E_i<100MeV) has been calculated including nucleonic and mesonic form factors by a double folding approach. Realistic density- and energy-dependent effective NN-interactions DDM3Y, BDM3Y and HLM3Y based on the Reid and Paris potentials are used in this respect. The ef

Denis V. Juriev

Some natural hidden symmetries in the Verma modules over the Virasoro algebra are constructed in terms of geometric quantization. Their differential geometric meaning is established and their expression via $q_R$-conformal symmetries in the Verma modules over the Lie algebra $sl(2,C)$ is found. The analysis and the unraveling of the algebraic structure of th

A. Khodjamirian, R. Rückl

We use operator product expansion and QCD light-cone sum rules to estimate the amplitude of the decay $B \to J/ψK $ taking into account leading nonfactorizable contributions. The result is very similar to the estimate obtained earlier from a four-point QCD sum rule. We discuss applications of this method to other nonleptonic $B$ decay modes.

Nick E. Mavromatos, Richard J. Szabo

We describe the short-distance properties of the spacetime of a system of D-particles by viewing their matrix-valued coordinates as coupling constants of a deformed worldsheet $σ$-model. We show that the Zamolodchikov metric on the associated moduli space naturally encodes properties of the non-abelian dynamics, and from this we derive new spacetime uncertai

Takuya Okabe

On the basis of the Fermi liquid theory, we investigate the many-body effect on the Drude weight. In a lattice system, the Drude weight $D$ is modified by electron-electron interaction due to Umklapp processes, while it is not renormalized in a Galilean invariant system. This is explained by showing that the effective mass $m&#39;$ for $D\propto n/m&#39;$ is

Predrag Cvitanovic&#39;, C. P. Dettmann, Ronnie Mainieri, Gabor Vattay

Periodic orbit theory is an effective tool for the analysis of classical and quantum chaotic systems. In this paper we extend this approach to stochastic systems, in particular to mappings with additive noise. The theory is cast in the standard field theoretic formalism, and weak noise perturbation theory written in terms of Feynman diagrams. The result is a

Peter Lundqvist

The H II region created by the progenitor of SN 1987A was further heated and ionized by the supernova flash. Prior to the flash, the temperature of the gas was 4000 - 5000 K, and helium was neutral, while the post-flash temperature was only slightly less than 10^5 K, with the gas being ionized to helium-like ionization stages of C, N and O. We have followed

Geoffrey T. Bodwin, Yu-Qi Chen

We analyze the renormalon ambiguities that appear in factorization formulas in QCD. Our analysis contains a simple argument that the ambiguities in the short-distance coefficients and operator matrix elements are artifacts of dimensional-regularization factorization schemes and are absent in cutoff schemes. We also present a method for computing the renormal

Marcelo Gleiser, Ronald Roberts

The breaking of an approximate discrete symmetry, the final stages of a first order phase transition, or a post-inflationary biased probability distribution for scalar fields are possible cosmological scenarios characterized by the presence of unstable domain wall networks. Combining analytical and numerical techniques, we show that the non-spherical collaps

Mikhail Bilenky, Susana Cabrera, Joan Fuster, Salvador Marti

We consider the production of heavy quark jets at the $Z$-pole at the next-to-leading order (NLO) using the {\it Cambridge jet-algorithm}. We study the effects of the quark mass in two- and three-jet observables and the uncertainty due to unknown higher order corrections as well as due to fragmentation. We found that the three-jet observable has remarkably s

V. F. Gantmakher, M. V. Golubkov, V. T. Dolgopolov, G. E. Tsydynzhapov

We have investigated the field-induced superconductivity-destroying quantum transition in amorphous indium oxide films at low temperatures down to 30 mK. It has been found that, on the high-field side of the transition, the magnetoresistance reaches a maximum and the phase can be insulating as well as metallic. With further increasing magnetic field the film

Christoph Schmid, Dominik J. Schwarz, Peter Widerin

The cosmological QCD transition affects primordial density perturbations. If the QCD transition is first order, the sound speed vanishes during the transition and density perturbations fall freely. For scales below the Hubble radius at the transition the primordial Harrison-Zel&#39;dovich spectrum of density fluctuations develops large peaks and dips. These

S. Dye, A. Taylor

We present a new method for directly determining accurate, self-consistent cluster lens mass and shear maps in the strong lensing regime from the magnification bias of background galaxies. The method relies upon pixellisation of the surface mass density distribution which allows us to write down a simple, solvable set of equations. We also show how pixellisa

K. Behrndt, A. H. Chamseddine, W. A. Sabra

BPS black hole solutions of U(1) gauged five-dimensional supergravity are obtained by solving the Killing spinor equations. These extremal static black holes live in an asymptotic AdS_5 space time. Unlike black holes in asymptotic flat space time none of them possess a regular horizon. We also calculate the influence, of a particular class of these solutions

S. Yoshida, Y. Eriguchi

A numerical method of mode analysis of rapidly rotating relativistic stellar models by the Cowling approximation is applied to rotating neutron stars with realistic equations of state. For selected equations of state, eigenvalues and eigenfunctions of f-modes are numerically solved for stellar models from non-rotating to maximally rotating states. Neutral po

Jeong-Hyuck Park

Superconformal symmetry in six-dimensions is analyzed in terms of coordinate transformations on superspace. A superconformal Killing equation is derived and its solutions are identified in terms of supertranslations, dilations, Lorentz transformations, R-symmetry transformations and special superconformal transformations. The full superconformal symmetry, wh

Miguel S. Costa

A D-5-brane bound state with a self-dual field strength on a 4-torus is considered. In a particular case this model reproduces the D5-D1 brane bound state usually used in the string theory description of 5-dimensional black holes. In the limit where the brane dynamics decouples from the bulk the Higgs and Coulomb branches of the theory on the brane decouple.

D. Iellici, E. S. Moreira

An ambiguity in the computation of the one-loop effective action for fields living on a cone is illustrated. It is shown that the ambiguity arises due to the non-commutativity of the regularization of ultraviolet and (conical) boundary divergencies.

Hisashi Kondo, Tôru Moriya

Spin fluctuation-induced superconductivity in two-dimensional organic compounds such as κ-(ET)_2-X is investigated by using a simplified dimer Hubbard model with right-angled isosceles triangular lattice (transfer matrices -τ, -τ^\prime). The dynamical susceptiblity and the self-energy are calculated self-consistently within the fluctuation exchange approxim

R. Nebauer, J. Aichelin

Since years it has been vividly debated whether multifragmentation is a thermal or a dynamical process. Recently it has been claimed \cite{toek1,po} that new data allow to decide this question. The conclusion, drawn in these papers, are, however, opposite. Whereas \cite{toek1} states that the behavior of different observables as a function of the fragment mu

D. F. V. James, M. S. Gulley, M. H. Holzscheiter, R. J. Hughes

We briefly review the development and theory of an experiment to investigate quantum computation with trapped calcium ions. The ion trap, laser and ion requirements are determined, and the parameters required for simple quantum logic operations are described

Daniel S. Abrams, Seth Lloyd

We describe a new polynomial time quantum algorithm that uses the quantum fast fourier transform to find eigenvalues and eigenvectors of a Hamiltonian operator, and that can be applied in cases (commonly found in ab initio physics and chemistry problems) for which all known classical algorithms require exponential time. Applications of the algorithm to speci

N Linden, S Popescu

Recently M. Horodecki, P. Horodecki and R. Horodecki have introduced a set of density matrices of two spin-1 particles from which it is not possible to distill any maximally entangled states, even though the density matrices are entangled. Thus these density matrices do not allow reliable teleportation. However it might nevertheless be the case that these st

H. Kleinert, D. H. Lin

We set up a trace formula for the relativistic density of states in terms of a topological sum of classical periodic orbits. The result is applicable to any relativistic integrable system.

Arun Kumar Pati

We recast Grover&#39;s generalised search algorithm in a geometric language even when the states are not approximately orthogonal. We provide a possible search algorithm based on an arbitrary unitary transformation which can speed up the steps still further. We discuss the lower and upper bounds on the transition matrix elements when the unitary operator cha

A. Arodzero

This paper describes a new framework in educational technology - the World Wide Student Laboratory (WWSL) Project. WWSL is a dynamic international Internet-based collaboration of resourses of educational and research labs of universities, institutions, government research centers and companies. The concepts of the WWSL are outlined, a possible idea for struc

Jan Toke, W. Udo Schroeder

It is shown that conclusions regarding the statistical nature of multifragmentation, drawn by Botvina and Gross from experimental data, are unfounded. Imperfections of the experimental apparatus cannot restore information, once destroyed by statistical fluctuations. Attention is also called to the special treatment of neutron phase space in the Berlin MMMC,

A. Bonaccorso, D. M. Brink

In this paper we study the energy spectra and related parallel momentum distributions of the neutrons from the breakup of 11Be. Earlier papers on transfer to the continuum reactions have shown that the breakup amplitude reduces to a simple eikonal approximation in the limit of weakly bound projectiles. The aim is to establish a reliable method to obtain info

A. Covello, L. Coraggio, A. Gargano

We have performed realistic shell-model calculations for nuclei around doubly magic 100Sn and 132Sn using an effective interaction derived from the Bonn A nucleon-nucleon potential. The results are in remarkably good agreement with the experimental data showing the ability of our effective interaction to provide an accurate description of nuclear structure p

Jan Toke, W. Udo Schroeder

It is shown that the Comment by Phair et al. on PRL 77, 3514 (1996) does not challenge the paper by T&#245;ke et al. It is, in fact, consistent with all conclusions of the targeted paper. The Comment disputes claims never made.

D. Bandyopadhyay, S. K. Basu, C. Bhattacharya, S. Bhattacharya

The energy spectra of alpha particles have been measured in coincidence with the evaporation residues for the decay of the compound nucleus $^31$P produced in the reaction $^19$F (96 MeV) + $^12$C. The data have been compared with the predictions of the statistical model code CASCADE. It has been observed that significant deformation effect in the compound n

A. Joye, C. -E. Pfister

We review recent results concerning the exponential behaviour of transition probabilities across a gap in the adiabatic limit of the time-dependent Schrödinger equation. They range from an exponential estimate in quite general situations to asymptotic Landau-Zener type formulae for finite dimensional systems, or systems reducible to this case.

N. P. Landsman

This is a graduate-level introduction to C*-algebras, Hilbert C*-modules, vector bundles, and induced representations of groups and C*-algebras, with applications to quantization theory, phase space localization, and configuration space localization. The reader is supposed to know elementary functional analysis and quantum mechanics.

N. P. Landsman

Quantization relates Poisson algebras to $C^*$-algebras. The analysis of local gauge symmetries in algebraic quantum field theory is approached through the quantization of classical gauge theories, regarded as constrained dynamical systems. This approach is based on the analogy between symplectic reduction and Rieffel induction on the classical and on the qu

N. P. Landsman

A nonzero 2-cocycle $Γ\in Z^2(\g,\R)$ on the Lie algebra $\g$ of a compact Lie group $G$ defines a twisted version of the Lie-Poisson structure on the dual Lie algebra $\g^*$, leading to a Poisson algebra $C^{\infty}(\g_{(Γ)}^*)$. Similarly, a multiplier $c\in Z^2(G,U(1))$ on $G$ which is smooth near the identity defines a twist in the convolution product on

N. P. Landsman

A strict quantization of a compact symplectic manifold $S$ on a subset $I\subseteq\R$, containing 0 as an accumulation point, is defined as a continuous field of $C^*$-algebras $\{A_{\hbar}\}_{\hbar\in I}$, with $A_0=C_0(S)$, and a set of continuous cross-sections $\{Q(f)\}_{f\in C^{\infty}(S)}$ for which $Q_0(f)=f$. Here $Q_{\hbar}(f^*)=Q_{\hbar}(f)^*$ for

A. Opfermann, G. Papadopoulos

We present the construction of a large class of homogeneous KT, HKT and QKT manifolds, $G/K$, using an invariant metric on $G$ and the canonical connection. For this a decomposition of the Lie algebra of $G$ is employed, which is most easily described in terms of colourings of Dynkin diagrams of simple Lie algebras. KT structures on homogeneous spaces are as

Cesar Bautista

We show explicitly a generalised Lie algebra embedded in the positive and negative parts of the Drinfeld-Jimbo quantum groups of type A_n. Such a generalised Lie algebra satisfy axioms closely related to the ones found by S.L. Woronowicz. For the universal enveloping algebra of such generalised Lie algebras we establish several conditions in order to obtain

Mark Brittenham

A persistent lamination for a knot K is an essential lamination in the complement of K, which remains essential after every non-trivial Dehn surgery along K. Having a persistent lamination implies, for example, that every manifold obtained by non-trivial Dehn surgery along K has universal cover R^3. In this paper we present a method for building persistent l

Mark Brittenham

A persistent lamination for a knot K is an essential lamination in the complement of the K, which remains essential after every non-trivial Dehn surgery along K. In particular, this implies that all of the Dehn surgery manifolds have universal cover R^3. This paper presents a method for building tangles T with the property that every knot K obtained by tangl

L. Accardi, S. V. Kozyrev, I. V. Volovich

A model of particle interacting with quantum field is considered. The model includes as particular cases the polaron model and non-relativistic quantum electrodynamics. We show that the field operators obey q-commutation relations with q depending on time. After the stochastic (or van Hove) limit, due to the nonlinearity, the atomic and field degrees of free

D. Ioffe, Y. Velenik

We prove that for a class of massless $\nablaϕ$ interface models on $\Ztwo$ an introduction of an arbitrary small pinning self-potential leads to exponential decay of correlation, or, in other words, to creation of mass.

J. -D. Deuschel, Y. Velenik

We consider a model of a two-dimensional interface of the SOS type, with finite-range, even, strictly convex, twice continuously differentiable interactions. We prove that, under an arbitrarily weak potential favouring zero-height, the surface has finite mean square heights. We consider the cases of both square well and $δ$ potentials. These results extend p

H. Garcia-Compean, O. Obregon, C. Ramirez

Recently a strong-weak coupling duality in non-abelian non-supersymmetric theories in four dimensions has been found. An analogous procedure is reviewed, which allows to find the `dual action&#39; to the gauge theory of dynamical gravity constructed by the MacDowell-Mansouri model plus the superposition of a $Θ$ term.

Katsushi Ito, Chuan-Sheng Xiong, Sung-Kil Yang

In view of two-dimensional topological gravity coupled to matter, we study the Seiberg-Witten theory for the low-energy behavior of N=2 supersymmetric Yang-Mills theory with ADE gauge groups. We construct a new solution of the Picard-Fuchs equations obeyed by the Seiberg-Witten periods. Our solution is expressed as the linear sum over the infinite set of one

Jose M Figueroa-O&#39;Farrill

This is the written version of my talk at SUSY &#39;98. It presents a geometric characterisation of the allowed near-horizon geometries of supersymmetric branes. We focus primarily on the M2-brane, but results for other branes (e.g., the D3-brane) are also presented. Some new examples are discussed.

Otto C. W. Kong

The origin of CP violation is a major mystery, especially in relation to the strong CP problem. CP being a spontaneously broken symmetry could provide an elegant solution. However, such models have difficulty making themselves compatible with low-energy supersymmetry, which is popularly accepted as the solution to the hierarchy problem. We demonstrate that a

J. C. Osborn, J. J. M. Verbaarschot

Eigenvalues and eigenfunctions of the QCD Dirac operator are studied for an instanton liquid partition function. We find that for energy differences $δE$ below an energy scale $E_c$, identified as the Thouless energy, the eigenvalue correlations are given by Random Matrix Theory. The value of $E_c$ shows a weak volume dependence for eigenvalues near zero and

S. Munier, R. Peschanski, Ch. Royon

Using the QCD dipole picture of the hard BFKL pomeron, we derive the general expressions of the elastic and inelastic components of the proton diffractive structure functions. We obtain a good 7 parameter fit (including a secondary reggeon contribution) to data taken at HERA by the H1 and ZEUS collaborations. The main characteristic features of the model in

P. Taxil, J. -M. Virey

Theoretical and phenomenological arguments are in favor of an elusive new neutral vector boson Z&#39; with a relatively low mass, chiral couplings to ordinary quarks and whose couplings to ordinary leptons are suppressed (leptophobia). We point out that this new particle could induce some parity violating spin asymmetries which could be measured soon at the

V. P. Gusynin, A. V. Smilga

We study the electron self--energy in a strong magnetic field when the parameter η\equiv (α/2π) \ln^2 (eB/m^2_0) \sim 1 and explore the transition between the perturbative regime η<<1 and the nonperturbative massless QED regime η>>1 where chiral symmetry is broken spontaneously and electrons acquire the dynamically induced mass.

T. Babutsidze, T. Kopaleishvili, A. G. Rusetsky

Bound q\bar q systems are studied in the framework of different 3-dimensional relativistic equations derived from the Bethe-Salpeter equation with the instantaneous kernel in the momentum space. Except the Salpeter equation, all these equations have a correct one-body limit when one of the constituent quark masses tends to infinity. The spin structure of the

G. Raffelt

Positive evidence for neutrino oscillations is mounting from the solar and atmospheric neutrino anomalies and the LSND experiment. Accordingly, the neutrino mass differences appear to lie in the sub-eV range and at least some of the mixing angles appear to be large. We explore some of the consequences of this picture for supernova (SN) physics and cosmology.

S. Geer, J. Marriner, R. Ray, J. Streets

A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on six antiproton decay modes which contain a final-state muon. At the 90% C.L. we find that tau/B(mu gamma) > 5.0 x 10^4 yr, tau/B(mu pi0) > 4.8 x 10^4 yr, tau/B(mu eta) > 7.9 x 10^3 yr, tau/B(mu gamma gamma) > 2.3 x 10^4 yr, tau/B(mu K0S > 4.3 x 10^3 yr, a

N. P. Landsman

The need for a mathematically rigorous quantization procedure of singular spaces and incomplete motions is pointed out in connection with quantum cosmology. We put our previous suggestion for such a procedure, based on the theory of induced representations of C*-algebras, in the light of L. Schwartz&#39; theory of Hilbert subspaces. This turns out to account

J. A. Vickers, J. P. Wilson

The coordinate invariant theory of generalised functions of Colombeau and Meril is reviewed and extended to enable the construction of multi-index generalised tensor functions whose transformation laws coincide with their counterparts in classical distribution theory.

A. Borowiec, M. Francaviglia

We shall use the variational decomposition technique in order to calculate equations of motion and Noether energy-momentum complex for some classes of non-linear gravitational Lagrangians within the first-order (Palatini) formalism. In particular, a complex space-time appears as a solution of our variational problem.

Semyon Pol&#39;shin

The basic principles of generalization of the group theoretical approach to the relativistic wave equations on curved spaces are examined. The general method of the determination of wave equations from the known symmetry group of a symmetrical curved space is described. The method of obtaining the symmetrical spaces in which invariant wave equations admit th

Olga Perkovic, Karin A. Dahmen, James P. Sethna

We present numerical simulations of avalanches and critical phenomena associated with hysteresis loops, modeled using the zero-temperature random-field Ising model. We study the transition between smooth hysteresis loops and loops with a sharp jump in the magnetization, as the disorder in our model is decreased. In a large region near the critical point, we

Muhittin Mungan, Chorng-Haur Sow, Susan N. Coppersmith, David G. Grier

We examine metastable configurations of a two-dimensional system of interacting particles on a quenched random potential landscape and ask how the configurational pair correlation function is related to the particle interactions and the statistical properties of the potential landscape. Understanding this relation facilitates quantitative studies of magnetic

F. Zhou, C. Biagini

We find the spin polarized disordered Fermi liquids are unstable to the nucleation of superconducting pairing states at mesoscopic scales even when magnetic fields which polarize the spins are substantially higher than the critical one. We study the probability of finding superconducting pairing states at mesoscopic scales in this limit. We find that the dis

Stefano Ghirlanda, Francesco Guerra

For a very general class of probability distributions in disordered Ising spin systems, in the thermodynamical limit, we prove the following property for overlaps among real replicas. Consider the overlaps among s replicas. Add one replica s+1. Then, the overlap q(a,s+1) between one of the first s replicas, let us say a, and the added s+1 is either independe

Stefan Heinrichs, William J. Mullin

Path-Integral-Monte-Carlo simulation has been used to calculate the properties of a two-dimensional (2D) interacting Bose system. The bosons interact with hard-core potentials and are confined to a harmonic trap. Results for the density profiles, the condensate fraction, and the superfluid density are presented. By comparing with the ideal gas we easily obse

N. Gayathri, A. K. Raychaudhuri, X. Q. Xu, J. L. Peng

We report a study of the magnetoresistance (MR) of the metallic perovskite oxide LaNiO$_{3-δ}$ as a function of the oxygen stoichiometry $δ$ ($δ\leq$ 0.14), magnetic field (H $\leq 6T$) and temperature (1.5K $\leq $ T $\leq $ 25K). We find a strong dependence of the nature of MR on the oxygen stoichiometry. The MR at low temperatures change from positive to