March 1997 arXiv papers — page 13

Francisco J. Solis, Louis Tao

We discuss properties of random fractals by means of a set of numbers that characterize their universal properties. This set is the generalized singularity specturm that consists of the usual spectrum of mulitfractal dimensions and the associated complex analogs. Furthermore, non-universal properties are recovered from the study of a series of functions whic

Lev N. Shchur, Henk W. J. Blöte

We present an extensive analysis of systematic deviations in Wolff cluster simulations of the critical Ising model, using random numbers generated by binary shift registers. We investigate how these deviations depend on the lattice size, the shift-register length, and the number of bits correlated by the production rule. They appear to satisfy scaling relati

Matthias Troyer, Masatoshi Imada

We present high precision estimates of the exponents of a quantum phase transition in a planar antiferromagnet. This has been made possible by the recent development of cluster algorithms for quantum spin systems, the loop algorithms. Our results support the conjecture that the quantum Heisenberg antiferromagnet is in the same universality class as the O(3)

K. Ziegler, M. H. Hettler, P. J. Hirschfeld

In a recent Comment (cond-mat/9701197) on our Letter (PRL 77, 3013 (1996), cond-mat/9604176) Nersesyan and Tsvelik questioned the relevance of our exact calculation of the density of states (DOS) of a 2D d-wave superconductor using a Lorentzian disorder distribution, claiming ``that models with Lorentzian and Gaussian disorder belong to different universalit

K. Ziegler, M. H. Hettler, P. J. Hirschfeld

We consider a disordered d--wave superconductor in two dimensions. Recently, we have shown in an exact calculation that for a lattice model with a Lorentzian distributed random chemical potential the quasiparticle density of states at the Fermi level is nonzero. As the exact result holds only for the special choice of the Lorentzian, we employ different meth

Caroline Barriere, Fred Popowich

Knowledge structures called Concept Clustering Knowledge Graphs (CCKGs) are introduced along with a process for their construction from a machine readable dictionary. CCKGs contain multiple concepts interrelated through multiple semantic relations together forming a semantic cluster represented by a conceptual graph. The knowledge acquisition is performed on

F. Toscano, R. O. Vallejos, M. Saraceno

We evaluate the leading asymptotic contributions to the traces of the quantum baker's map propagator. Besides the usual Gutzwiller periodic orbit contribution, we identify boundary paths giving rise to anomalous log(hbar) terms. Some examples of these anomalous terms are calculated both numerically and analytically.

Michael D. Gregg

The diameter - velocity dispersion relation in B, V, and K for three early-type galaxies in the Leo I (M96) group is derived from published photometry and kinematic data. The relations in all three colors have slopes which agree well with those for the Coma cluster. The RMS scatter of the Leo I galaxies in each color is extremely small, consistent with the g

J. Gorgas, S. Pedraz, R. Guzman, N. Cardiel

We present new measurements of central line-strength indices (namely Mg2, <Fe>, and Hbeta and gradients for a sample of 6 bright spheroidal galaxies (Sph&#39;s) in the Virgo cluster. Comparison with similar measurements for elliptical galaxies (E&#39;s), galactic globular clusters (GGC&#39;s), and stellar population models yield the following results: (1) In

R. Brent Tully, Marc A. W. Verheijen

The Ursa Major Cluster appears to be unevolved and made up of HI-rich spiral galaxies. B,R,I,K&#39; photometry has been obtained for 79 galaxies, including 62 in a complete sample with M(B)<-16.5 mag. The K&#39; information is particularly important for the present discussion because it is not seriously affected by obscuration. There is reasonably convincing

J. Isern, R. Mochkovitch, E. García--Berro, Margarita Hernanz

White dwarfs can be used as galactic chronometers and, therefore, provide important information about galactic evolution if good theoretical models of their cooling are available. Consequently, it is natural to wonder if all the sources or sinks of energy are correctly taken into account. One of these sources is partial differentiation of the chemical compon

Paolo Salucci, Massimo Persic

We present evidence that all galaxies, of any Hubble type and luminosity, bear the kinematical signature of a mass component distributed differently from the luminous matter. We review and/or derive the DM halo properties of galaxies of different luminosities and morphologies: spirals, LSBs, ellipticals, dwarf irregulars and dwarf spheroidals.

F. R. Ferraro, B. Paltrinieri, F. Fusi Pecci, C. Cacciari

The core of the Galactic Globular Cluster M3 (NGC 5272) has been observed with the WFPC2 through the filters F255W, F336W, F555W, and F814W. Using these observations along with a thorough reanalysis of earlier catalogs, we have produced a catalog of blue straggler stars (BSS) spanning the cluster. Earlier studies and the fainter part of our sample suffer sev

Michiel van der Klis, Rudy A. D. Wijnands, Keith Horne, Wan Chen

We report on a series of twenty ~10^5 c/s, 0.125 msec time-resolution RXTE observations of the Z source and low-mass X-ray binary Scorpius X-1. Twin kilohertz quasi-periodic oscillation (QPO) peaks are obvious in nearly all observations. We find that the peak separation is not constant, as expected in some beat-frequency models, but instead varies from ~310

Marco Scodeggio, Riccardo Giovanelli, Martha Haynes

We show that it is possible to define a purely Photometric Fundamental Plane (PFP) for early-type galaxies. This relation is similar to the standard Fundamental Plane (FP), and is obtained by replacing the velocity dispersion parameter with the difference between the magnitude of a galaxy and that of the mode of the Gaussian luminosity function of E and S0 g

Jeffrey A. Newman, Michael Eracleous, Alexei V. Filippenko, Jules P. Halpern

The optical spectrum of the broad-line radio galaxy Arp 102B has been monitored for more than thirteen years to investigate the nature of the source of its broad, double-peaked hydrogen Balmer emission lines. The shape of the lines varied subtly; there was an interval during which the variation in the ratio of the fluxes of the two peaks appeared to be sinus

Arthur Robb, Mina Teicher

Every smooth minimal complex algebraic surface of general type, $X$, may be mapped into a moduli space, $\MM_{c_1^2(X), c_2(X)}$, of minimal surfaces of general type, all of which have the same Chern numbers. Using the braid group and braid monodromy,we construct infinitely many new examples of pairs of minimal surfaces of general type which have the same Ch

Philip A. Foth

We consider the moduli spaces of flat $SL(n, C)$-bundles on Riemann surfaces with one puncture when we fix the conjugacy class ${\cal C}$ of the monodromy transformation around the puncture. We show that under a certain condition on the class ${\cal C}$ (namely the product of $k<n$ eigenvalues is not equal to $1$) that we call property P the moduli space in

Jon Loveday

We estimate the luminosity function of field galaxies over a range of ten magnitudes (-22 < M_{B_J} < -12 for H_0 = 100 km/s/Mpc) by counting the number of faint APM galaxies around Stromlo-APM redshift survey galaxies at known distance. The faint end of the luminosity function rises steeply at M_{B_J} \approx -15, implying that the space density of dwarf ga

R. Dijkgraaf, E. Verlinde, H. Verlinde

Via compactification on a circle, the matrix model of M-theory proposed by Banks et al suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and t

W. L. Smith, R. B. Mann

We consider the gravitational collapse of a dust cloud in an asymptotically anti de Sitter spacetime in which points connected by a discrete subgroup of an isometry subgroup of anti de Sitter spacetime are identified. We find that black holes with event horizons of any topology can form from the collapse of such a cloud. The quasilocal mass parameter of such

Alon E. Faraggi, Jogesh Pati

In Gravity Unified Theories all operators that are consistent with the local gauge and discrete symmetries are expected to arise in the effective low-energy theory. Given the absence of multiplets like 126 of SO(10) in string models, and assuming that B-L is violated spontaneously to generate light neutrino masses via a seesaw mechanism, it is observed that

Eric M. Rains, R. H. Hardin, Peter W. Shor, N. J. A. Sloane

Up to now every good quantum error-correcting code discovered has had the structure of an eigenspace of an Abelian group generated by tensor products of Pauli matrices; such codes are known as stabilizer or additive codes. In this letter we present the first example of a code that is better than any code of this type. It encodes six states in five qubits and

Vladimir V. Kisil

Looking to the history of mathematics one could find out two outer approaches to Geometry. First one (algebraic) is due to Descartes and second one (group-theoretic)--to Klein. We will see that they are not rivalling but are tied (by Galois). We also examine their modern life as philosophies of non-commutative geometry. Connections between different objects

Pawel Horodecki

It is shown that any separable state on Hilbert space ${\cal H}={\cal H}_1\otimes{\cal H}_2$, can be written as a convex combination of N pure product states with $N\leq (dim{\cal H})^2$. Then a new separability criterion for mixed states in terms of range of density matrix is obtained. It is used in construction of inseparable mixed states with positive par

B. S. Acharya

We give some simple examples of mirror Calabi-Yau fourfolds in Type II string theory. These are realised as toroidal orbifolds. Motivated by the Strominger, Yau, Zaslow argument we give explicitly the mirror transformation which maps Type IIA/IIB on such a fourfold to Type IIA/IIB on the mirror. The mirrors are related by the inclusion/exclusion of discrete

M. Harada, A. Qamar, F. Sannino, J. Schechter

We calculate the next-to-leading order contribution to the masses of the heavy baryons in the bound state approach for baryons containing a heavy quark. These $1/N_C$ corrections arise when states of good spin and isospin are generated from the background soliton of the light meson fields. Our study is motivated by the previously established result that ligh

I. I. Kogan, A. Lewis, O. A. Soloviev

We study correlation functions of coset constructions by utilizing the method of gauge dressing. As an example we apply this method to the minimal models and to the Witten 2D black hole. We exhibit a striking similarity between the latter and the gravitational dressing. In particular, we look for logarithmic operators in the 2D black hole.

Arjun Berera, Li-Zhi Fang, Gary Hinshaw

Inflationary cosmology predicts that the particle horizon should be generically much bigger than the present-day Hubble radius, $1/H_0$. This implies a special regime of super-Hubble scale energy density fluctuations imprinted on the cosmic microwave background radiation (CMBR), which from present theory could only be explained by inflation Causality constra

R. M. Ellem, V. V. Bazhanov

We give further support to Smirnov&#39;s conjecture on the exact kink S-matrix for the massive Quantum Field Theory describing the integrable perturbation of the c=0.7 minimal Conformal Field theory (known to describe the tri-critical Ising model) by the operator $ϕ_{2,1}$. This operator has conformal dimensions $(7/16,7/16)$ and is identified with the suble

Bogdan R. Bulka

The slave boson mean-field studies of the ground state of the Hubbard model with correlated hopping were performed. The approach qualitatively recovers the exact results for the case of the hopping integral t equal to the correlated hopping integral X. The phase diagram for the strongly correlated state with only singly occupied sites, the weakly correlated

A. J. Macfarlane, A. J. Mountain

This paper addresses an issue essential to the study of hidden supersymmetries (meaning here ones that do not close on the Hamiltonian) for one-dimensional non-linear supersymmetric sigma models. The issue relates to ambiguities, due to partial integrations in superspace, both in the actual definition of these supersymmetries and in the Noether definition of

C. M. Marcus, S. R. Patel, A. G. Huibers, S. M. Cronenwett

This paper reviews recent studies of mesoscopic fluctuations in transport through ballistic quantum dots, emphasizing differences between conduction through open dots and tunneling through nearly isolated dots. Both the open dots and the tunnel-contacted dots show random, repeatable conductance fluctuations with universal statistical proper-ties that are acc

T. Fujiwara, H. Igarashi, Y. Takimoto

The exact operator solution for quantum Liouville theory constructed for the generic quantum deformation parameter $q$ is extended to the case with $q$ being a root of unity. The screening charge operator becomes nilpotent in such cases and arbitrary Liouville exponentials can be obtained in finite polynomials of the screening charge.

A. Hocker

We present new results of the tau hadronic spectral function analysis using data accumulated by the ALEPH detector at LEP during the years 1991-94. In addition to the vector spectral functions, the axial-vector spectral functions and, separately, the tau --> 3pi nu as well as the tau --> pi 2pi0 nu spectral functions are determined from their respective unfo

S. Ya. Startsev

An algorithm is constructed which allows to express conserved flows of hyperbolic equations in terms of corresponding conserved densities and to eliminate these flows from conservation laws of hyperbolic equations. The application of this algorithm to canonical conservation laws gives constructive necessary integrability conditions of hyperbolic equations in

L. Lanz, O. Melsheimer, B. Vacchini

It is argued that the dynamics of an isolated system, due to the concrete procedure by which it is separated from the environment, has a non-Hamiltonian contribution. By a unified quantum field theoretical treatment of typical subdynamics, e.g., hydrodynamics, kinetic theory, master equation for a particle interacting with matter, we look for the structure o

Igor Frenkel, Alexander Kirillov, Alexander Varchenko

Using the isomorphism between highest weight U_q(sl_2)-modules and homologies of certain local systems on the configuration spaces, constructed by Varchenko, we give a geometric construction of the dual of the Lusztig&#39;s canonical basis in a tensor product of irreducible finite-dimensional U_q(sl_2)-modules.

Howard J. Schnitzer

A discussion of different criteria of consistency of quantum field theory from the point of view of physics and mathematics.

T. Tikkanen, S. Kraft, F. Scholze, R. Thornagel

The detection efficiency and response function of a Si(Li) detector element for the SIXA spectrometer have been determined in the 500 eV to 5 keV energy range using synchrotron radiation emitted at a bending magnet of the electron storage ring BESSY, which is a primary radiation standard. The agreement between the measured spectrum and the model calculation

V. B. Deyirmenjian, Zahir A. Daya, Stephen W. Morris

It has been experimentally observed that weakly conducting suspended films of smectic liquid crystals undergo electroconvection when subjected to a large enough potential difference. The resulting counter-rotating vortices form a very simple convection pattern and exhibit a variety of interesting nonlinear effects. The linear stability problem for this syste

V. V Burov, A. V. Molochkov

The role of relativistic off-mass-shell kinematics in the deep inelastic scattering on deuteron is analyzed. It is shown that the relativistic impulse approximation reproduces effects from the binding, Fermi motion, and two-nucleon contribution. The nonrelativistic limit of the deuteron structure function is in agreement with the nonrelativistic calculations

P. J. A. Bicudo, L. S. Ferreira, C. M. Plácido, J. E. F. T. Ribeiro

We work in a chiral invariant quark model, with a condensed vacuum, characterized by only one parameter. Bound state equations for the nucleon and Delta are solved in order to obtain an updated value of their radii and masses. Nucleon-nucleon S-Wave scattering is studied in the RGM framework both for isospin T=1 and T=0. The phase shifts are calculated and a

Michael Douglas, Joseph Polchinski, Andrew Strominger

We consider a one-brane probe in the presence of a five-dimensional black hole in the classical limit. The velocity-dependent force on a slowly-moving probe is characterized by a metric on the probe moduli space. This metric is computed for large black holes using low-energy supergravity, and for small black holes using D-brane gauge theory. The results are

André Martin

We show that if for fixed negative (physical) square of the momentum transfer t, the differential cross-section ${dσ\over dt}$ tends to zero and if the total cross-section tends to infinity, when the energy goes to infinity, the real part of the even signature amplitude cannot have a constant sign near t = 0.

A. N. Leznov

The new class of integrable mappings and chains is introduced. Corresponding (1+2) integrable systems invariant with respect to such discrete transformations are represented in explicit form. Soliton like solutions of them are represented in terms of matrix elements of fundamental representations of semisimple A_n algebras for a given group element.

M. J. Martins, P. B. Ramos

In this paper we study isotropic integrable systems based on the braid-monoid algebra. These systems constitute a large family of rational multistate vertex models and are realized in terms of the B_n, C_n and D_n Lie algebra and by the superalgebra Osp(n|2m). We present a unified formulation of the quantum inverse scattering method for many of these lattice

Kenneth Lane

Topcolor-assisted technicolor provides a dynamical explanation for electroweak and flavor symmetry breaking and for the large mass of the top quark without unnatural fine tuning. I briefly review the basics of topcolor-assisted technicolor, including major constraints and a general approach to satisfying them. The main challenge to topcolor-assisted technico

Ewan D. Stewart

In a previous paper I showed that a classical scalar potential with $V&#39;&#39;/V \sim 1$ can be sufficiently flattened by quantum corrections to give rise to slow-roll inflation. In this paper I give a hybrid inflation implementation of that idea which can naturally produce a spectral index in the observationally viable range even for $V^{1/4} \sim 10^{10}

W. Hollik

1-loop diagrammatic calculations of cross sections and decay widths of neutral Higgs bosons in the minimal supersymmetric standard model are reviewed and compared with compact expressions in the effective potential approximation.

Abdelhak Djouadi

I discuss the decay modes of the neutral and charged Higgs bosons in the minimal supersymmetric extension of the Standard Model. Special emphasis will be put on the the QCD corrections to the hadronic decay modes, the below threshold -three body- decays and the decays into supersymmetric particles, charginos, neutralinos and sfermions. A Fortran code calcula

P. Bicudo

At the BCS level of chiral symmetry breaking, the mass gap equation for quark-antiquark condensation only uses the kernel of the Bethe-Salpeter equation. We introduce coupled channels with ladder mesons in the mass gap equation. Consistency is insured by the Ward Identity for axial currents, and the $π$ remains a Goldstone boson in the chiral limit. We find

Daniel de Florian, Rodolfo Sassot

We analyse recent data on the production of forward neutrons in deep inelastic scattering at HERA in the framework of a perturbative QCD description for semi-inclusive processes, which includes fracture functions. Using a model estimate for the non-perturbative piece of the fragmentation process, in fairly good agreement with the available data, we analyse t

K. Fiałkowski, R. Wit

A practical method of calculating weights implementing the Bose - Einstein interference effects is presented. The usefulness of the method is demonstrated for the events generated by the JETSET/PYTHIA code to describe the UA1 proton-antiproton data at 630GeV. A good description of data is achieved with a reasonable value of the Gaussian width of a two-partic

K. G. Chetyrkin, B. A. Kniehl, A. Sirlin

A simple procedure to estimate O(alpha_s^3) and O(alpha_s^4) corrections to mass-dependent observables is conjectured. The method is tested in a number of cases where the O(alpha_s^3) contribution is exactly known, and reasonable agreement is found.

J. R. Forshaw, P. J. Sutton

We study the high energy behaviour of elastic scattering amplitudes within the leading logarithm approximation. In particular, we cast the amplitude in a form which allows us to study the internal dynamics of the BFKL Pomeron for general momentum transfer. We demonstrate that the momentum transfer acts as an effective infrared cut-off which ensures that the

S. Mrenna, C. -P. Yuan

The resummation of multiple soft gluon emission affects the production rate and kinematic distributions of $W^+h$ (where h is a Higgs boson) and $t \bar b$ pairs at the Tevatron with $\sqrt{s}=2$ TeV. Using the Collins-Soper-Sterman resummation formalism, the production rate is enhanced over the next-to-leading-order (NLO) prediction by 2-3% for the $W^+h$ p

R. C. Verma

Weak decays of heavy flavor hadrons play a special role in our understanding of physics of the Standard Model and beyond. The measured quantities, however, result from a complicated interplay of weak and strong interactions. Weak leptonic and semileptonic decays are reasonably well understood, whereas weak hadronic decays present challenges to theory. In thi

T. Goldman

In infrared-stable fixed-point field theories, the interaction energy of a test particle is proportional to the non-relativistic (heavy source) coordinate-space potential derived from the field strength produced by that source. This is no longer true in ultraviolet-stable fixed-point field theories (UVSFPFT) as they may not have a finite infrared fixed point

S. Bar-Shalom, G. Eilam, A. Soni, J. Wudka

The reactions e+e- -> t bar-c nu_e bar-nu_e, t bar-c e+ e- are very sensitive probes of the flavor-changing-scalar couplings which can occur in a model with one extra Higgs doublet. At the Next Linear Collider, with a center of mass energy of sqrt{s}=0.5--2 TeV, several hundreds and up to thousands of such events may be produced if the mass of the light neut

The HERMES Collaboration, K. Ackerstaff

Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function $g_1^n(x,Q^2)$ in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized $^3$He internal gas target. The data cover the kinematic range $0.023<x<0.6$ and $1 (GeV/c)^2 < Q^2 <15 (GeV/c)^2$. The integral $

Andrew Abrahams, Arlen Anderson, Yvonne Choquet-Bruhat, James W. York,

Two geometrical well-posed hyperbolic formulations of general relativity are described. One admits any time-slicing which preserves a generalized harmonic condition. The other admits arbitrary time-slicings. Both systems have only the physical characteristic speeds of zero and the speed of light.

H. Wissowski, H. A. Kastrup

Bianchi -I, -III, and FRW type models minimally coupled to a massive spatially homogeneous scalar field (i.e. a particle) are studied in the framework of semiclassical quantum gravity. In a first step we discuss the solutions of the corresponding equation for a Schrödinger particle propagating on a classical background. The back reaction of the Schrödinger p

Renaud Parentani

We extract transition amplitudes among matter constituents of the universe from the solutions of the Wheeler De Witt equation. The physical interpretation of these solutions is then reached by an analysis of the properties of the transition amplitudes. The interpretation so obtained is based on the current carried by these solutions and confirms ideas put fo

Jun Hu, A. H. MacDonald

We report on a Monte Carlo study of the lowest-Landau-level limit of the Lawrence-Doniach model for a layered superconductor. We have studied order parameter correlation functions for indications of the broken translational symmetry and the off-diagonal long range order present in the mean-field-theory vortex lattice. Our results are consistent with a single

Jacek Dziarmaga

Dynamics of magnetic bubbles in planar ferromagnets described by the Landau-Lifshitz equation with dissipation is analyzed. The pure O(3) sigma model has static multisoliton solutions, characterized by a number of parameters. The parameters describe a finite dimensional manifold. A small perturbation of energy functional with respect to the sigma model force

H. Kachkachi, P. Kornilovitch, Y. Meurdesoif, J. -C. Grenier

Using a Dirac-Heisenberg Hamiltonian with biquadratic exchange interactions, we study the effect of iron disproportionation on the magnetic ordering, and describe the first-order magnetic transition occurring in the perovskite Sr_{2}LaFe_{3}O_{9}. Upon fitting the experimental data, we give an estimate of the exchange integrals for the antiferromagntic and f

Lydéric Bocquet, Henrik Jeldtoft Jensen

When a elastic body is moved quasistatically back and forth over a surface, the friction of the interface is experimentally observed to circulate through a hysteretic loop. The asymptotic behaviour of the hysteresis loop is approached exponentially. We describe how this behaviour is connected to the collective properties of the elastic instabilities suffered

O. V. Danylenko, O. V. Dolgov, V. V. Losyakov

In some newly discovered materials the ratio of phonon to electron energies is no longer small. We have investigated the basement of the recently proposed gauge-invariant self-consistent method and found conditions of its applicability.

G. Wellein, H. Fehske

We present numerical exact results for the polaronic band structure of the Holstein molecular crystal model in one and two dimensions. The use of direct Lanczos diagonalization technique, preserving the full dynamics and quantum nature of phonons, allows us to analyze in detail the renormalization of both quasiparticle bandwidth and dispersion by the electro

Frank A. Maao, Y. Galperin

A dc current induced in a quantum constriction by a traveling acoustic wave (or by non-equilibrium ballistic phonons) is considered. We show that in many important situations the effect is originated from acoustically-induced scattering between the propagating and reflecting states in the constriction. Two particular regimes corresponding to relatively high

Hyeonjin Doh, Seung-Pyo Hong, Sung-Ho Suck Salk

By allowing interactions between electrons, a new Harper&#39;s equation is derived to examine the effects of electron correlations on the Hofstadter energy spectra. It is shown that the structure of the Hofstadter butterfly ofr the system of correlated electrons is modified only in the band gaps and the band widths, but not in the characteristics of self-sim

M. T. Batchelor, V. Fridkin, A. Kuniba, K. Sakai

We obtain the free energies and critical exponents of models associated with elliptic solutions of the star-triangle relation and reflection equation. The models considered are related to the affine Lie algebras A_1^{(1)}, B_n^{(1)},C_n^{(1)} and D_n^{(1)}. The bulk and surface specific heat exponents are seen to satisfy the scaling relation 2α_s = α_b + 2.

Joerg P. Ueberla

In this paper, a method of domain adaptation for clustered language models is developed. It is based on a previously developed clustering algorithm, but with a modified optimisation criterion. The results are shown to be slightly superior to the previously published &#39;Fillup&#39; method, which can be used to adapt standard n-gram models. However, the impr

J. Timmer, S. Klein

A statistical test is presented to decide whether data are adequately described by probabilistic functions of finite state Markov chains (&#39;&#39;hidden Markov models&#39;&#39;) as applied in the analysis of ion channel data. Particularly, the test can be used to decide whether a system obeys the Markov condition. Simulation studies are performed in order

D. Beauchamp, E. Hardy

We describe an imaging method that makes use of interference filters to provide integrated stellar spectral indices for spiral disks to faint surface brightness limits. We use filters with bandpasses ~60A FWHM, centered on the Mg and Fe features (5176A and 5270A respectively) allowing the determination of the spatial distribution of the Lick indices Mg2 and

M. Guainazzi, G. Matt, L. Piro, N. R. Robba

Preliminary results of the RXTE observation of the Seyfert 2 Galaxy NGC4507 are presented. The observed broadband [4-100 keV] spectrum is intrinsically hard (Gamma = 1.2); an iron line is detected with a relatively high equivalent width (EW = 400 eV). The remaining calibration uncertanties are briefly discussed, as well as the scientific implications of our

A. J. Blair, I. Georgantopoulos, G. C. Stewart

We present ROSAT observations of two luminous L~10^44 erg/s EMSS galaxies, MS1019+5139 and MS1209+3917, previously classified as &#39;cooling flow&#39; galaxies. MS1019+5139 does not appear to be spatially extended (<13 kpc) while its spectrum is well fit by a power law with Gamma = 1.73 +0.19-0.18; X-ray variability on a timescale of ~ years is also clearly

D. S. Krivitsky, V. M. Kontorovich

A Monte Carlo simulation of mergers in clusters of galaxies is carried out. An ``explosive&#39;&#39; character of the merging process (an analog of phase transition), suggested earlier by Cavaliere et al. (1991), Kontorovich et al. (1992), is confirmed. In particular, a giant object similar to cD-galaxy is formed in a comparatively short time as a result of

G. E. Soberman, E. S. Phinney, E. P. J. van den Heuvel

The evolution of a binary star system by various analytic approximations of mass transfer is discussed, with particular attention payed to the stability of these processes against runaway on the thermal and dynamical timescales of the mass donating star. Mass transfer in red giant - neutron star binary systems is used as a specific example of such mass trans

R. Alemany, M. Davier, A. Hocker

We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon (g-2) and to the running of the QED fine structure constant alpha(s) at s=M_Z**2. We incorporated new data from hadronic tau decays, recently published by the ALEPH Collaboration. In addition, compared to previous analyses, we use more extensive e+e- annihilation data

James J. Griffin

The best fit to the published APEX U+Th data describes a sharp line of 123 pairs of width 23 keV at 793$\pm$7 keV; also, the data impose a positive 99.0%CL lower bound of 23 sharp pairs. It is therefore untenable to argue from the APEX data against the existence of sharp pairs. Data-only ratios APEX/EPOS pair counts show empirically that the two experiments&

Tin-Lun Ho, Michael Ma

Current magnetic traps can be made so anisotropic that the atomic gas trapped inside behaves like quasi one or two dimensional system. Unlike the homogeneous case, quantum phase fluctuations do not destroy macroscopic off-diagonal order of trapped Bose gases in $d\leq 2$. In the dilute limit, quantum fluctuations increase, remain constant, and decrease with

Margit Rösler

Based on the theory of Dunkl operators, this paper presents a general concept of multivariable Hermite polynomials and Hermite functions which are associated with finite reflection groups on $\b R^N$. The definition and properties of these generalized Hermite systems extend naturally those of their classical counterparts; partial derivatives and the usual ex

R. Banerjee, J. Barcelos-Neto

We propose a systematic method of dealing with the canonical constrained structure of reducible systems in the Dirac and symplectic approaches which involves an enlargement of phase and configuration spaces, respectively. It is not necessary, as in the Dirac approach, to isolate the independent subset of constraints or to introduce, as in the symplectic anal

J. A. de Azcarraga, J. M. Izquierdo, J. C. Perez Bueno

The characterization of the Nambu-Poisson n-tensors as a subfamily of the Generalized-Poisson ones recently introduced (and here extended to the odd order case) is discussed. The homology and cohomology complexes of both structures are compared, and some physical considerations are made.

P. Zinn-Justin

In this article, a model of random hermitian matrices is considered, in which the measure $\exp(-S)$ contains a general U(N)-invariant potential and an external source term: $S=N\tr(V(M)+MA)$. The generalization of known determinant formulae leads to compact expressions for the correlation functions of the energy levels. These expressions, exact at finite $N

Sean Keel

I give a necessary and sufficient condition for a nef and big line bundle in positive characteristic to be semi-ample, and then give two applications: I show that the relative dualizing sheaf of the universal curve is semi-ample, in positive characteristic, and give a simple example which shows that this, and the semi-ampleness criterion, fail in characteris

S. Sinel&#39;shchikov, L. Vaksman

A very well known result by Harish-Chandra claims that any Hermitian symmetric space of non-compact type admits a canonical embedding into a complex vector space $V$. The image of this embedding is a bounded symmetric domain in $V$. This work provides a construction of q-analogues of a polynomial algebra on $V$ and the differential algebra of exterior forms

Per Elmfors, Kari Enqvist, Georg Raffelt, Günter Sigl

Neutrinos with a magnetic moment $μ$ change their helicity when interacting with an electromagnetic field. Various aspects of this effect have been described as spin precession, spin-flip scattering, and magnetic Cherenkov radiation. These perspectives are unified in an expression for the $ν_L\toν_R$ transition rate which involves the correlators of the elec

S. V. Kozyrev

Free coherent states for a system with two degrees of freedom is defined. An isomorphism of the space of distributions on 2-adic disc and the space of free coherent states is constructed.

Pei-Ming Ho, Yong-Shi Wu

In this paper we study duality properties of the M(atrix) theory compactified on a circle. We establish the equivalence of this theory to the strong coupling limit of type IIB string theory compactified on a circle. In the M(atrix) theory context, our major evidence for this duality consists of identifying the BPS states of IIB strings in the spectrum and fi

Fedor Bogomolov, Ludmil Katzarkov

The paper contains a general construction which produces new examples of non simply-connected smooth projective surfaces. We analyze the resulting surfaces and their fundamental groups. Many of these fundamental groups are expected to be non-residually finite. Using the construction we also suggest a series of potential counterexamples to the Shafarevich con

Lev Vaidman

It is argued that the proof of Cohen [Phys. Rev. A 51, 4373 (1995)] which shows that an application of the Aharonov-Bergmann-Lebowitz (ABL) rule leads to contradiction with predictions of quantum theory is erroneous. A generalization of the ABL rule for the case of an incomplete final measurement (which is needed for the analysis of Cohen&#39;s proof) is pre

S. Majid

We introduce braided Lie bialgebras as the infinitesimal version of braided groups. They are Lie algebras and Lie coalgebras with the coboundary of the Lie cobracket an infinitesimal braiding. We provide theorems of transmutation, Lie biproduct, bosonisation and double-bosonisation relating braided Lie bialgebras to usual Lie bialgebras. Among the results, t

Horia C. Pop

We prove that row reducing a quantum matrix yields another quantum matrix for the same parameter q. This means that the elements of the new matrix satisfy the same relations as those of the original quantum matrix ring M_q(n). As a corollary, we can prove that the image of the quantum determinant in the abelianization of the total ring of quotients of M_q(n)

Stephen G. Low

Born proposed a unification of special relativity and quantum mechanics that placed position, time, energy and momentum on equal footing through a reciprocity principle and extended the usual position-time and energy-momentum line elements to this space by combining them through a new fundamental constant. Requiring also invariance of the symplectic metric y

E. D. Belokolos

A new formulation of statistical mechanics is put forward according to which a random variable characterizing a macroscopic body is postulated to be infinitely divisible. It leads to a parametric representation of partition function of an arbitrary macroscopic body, a possibility to describe a macroscopic body under excitation by a gas of some elementary qua

L. Engvik, E. Osnes, M. Hjorth-Jensen, T. T. S. Kuo

In this work we investigate the so-called model-space Brueckner-Hartree-Fock (MBHF) approach for nuclear matter as well as for neutron matter and the extension of this which includes the particle-particle and hole-hole (PPHH) diagrams. A central ingredient in the model-space approach for nuclear matter is the boundary momentum $k_M$ beyond which the single-p

C. Bennhold, T. Mart, D. Kusno

Kaon photo- and electroproduction off the nucleon is investigated in the framework of an isobaric model up to energies of about 1 GeV above threshold for all six isospin channels. The hadronic coupling constants in the model are determined by fitting to the available experimental data. We give a brief status report on the state of these models and discuss pr