October 1999 arXiv papers — page 21

Paulo F. Bedaque

The influence of different chemical potential for different flavors on color superconductivity is analyzed. It is found that there is a first order transition as the asymmetry grows. This transition proceeds through the formation of bubbles of low density, flavor asymmetric normal phase inside a high density, superconducting phase with a gap {\it larger} tha

S. Heinemeyer, Th. Mannel, G. Weiglein

One year of Z- and WW-Threshold running of TESLA can provide the possibility to measure electroweak precision observables to an extremely high accuracy. At the Z peak O(10^9) Z bosons and about 6 10^8 b quarks can be collected. We employ the expected uncertainties ΔMW = 6 MeV and Δsin(theta_W,eff) = 0.00001 and demonstrate in this way that very stringent con

A. L. Kataev

An experimental motivated QCD analysis of the behaviour of the Adler D-function in the Euclidian region is described. It is stressed that by taking account of $b$-quark mass-dependent $α_s^2$-effects one obtains better agreement between theoretical predictions and experimentally motivated behaviour of the D-function at large Euclidian momentum transfer. A mo

A. Donini, V. Gimenez, L. Giusti, G. Martinelli

We introduce a new parameterization of four-fermion operator matrix elements which does not involve quark masses and thus allows a reduction of systematic uncertainties. In order to simplify the matching between lattice and continuum renormalization schemes, we express our results in terms of renormalization group invariant B-parameters which are renormaliza

R. Aloisio, V. Azcoiti, G. Di Carlo, A. Galante

Simulations in finite density, beta=0 lattice QCD by means of the Monomer-Dimer-Polymer algorithm show a signal of first order transition at finite temporal size. This behaviour agrees with predictions of the mean field approximation, but is difficult to reconcile with infinite mass analytical solution. The MDP simulations are considered in detail and severe

APEX Collaboration, S. Geer

A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on fifteen antiproton decay modes. The results are used to place limits on the characteristic mass scale Mx that could be associated with CPT-violation accompanied by baryon number violation.

Giovanni Amelino-Camelia

The recent paper gr-qc/9909017 criticizes the limit on the measurability of distances that was derived by Salecker and Wigner in the 1950s. If justified, this criticism would have important implications for all the recent studies that have used in various ways the celebrated Salecker-Wigner result, but I show here that the analysis reported in gr-qc/9909017

Mark Miller, Wai-Mo Suen, Malcolm Tobias

Shapiro put forth a conjecture stating that neutron stars in head-on collisions (infalling from infinity) will not collapse to black holes before neutrino cooling, independent of the mass of the neutron stars. In a previous paper we carried out a numerical simulation showing a counter example based on 1.4 $M_{\odot}$ neutron stars, and provided an analysis e

C. N. Ferreira, M. E. X. Guimaraes, J. A. Helayel-Neto

We study the implications of a scalar-tensorial gravity for the metric of an isolated self-gravitating superconducting cosmic string. These modifications are induced by an arbitrary coupling of a massless scalar field to the usual tensorial field in the gravitational Lagrangian. We derive the metric in the weak-field approximation and we analyse the behaviou

K. Ghafoori-Tabrizi, S. S. Gousheh, H. R. Sepangi

We analyse a classical model of gravitation coupled to a self interacting scalar field. We show that, within the context of this model for Robertson-Walker cosmologies, there exist solutions in the spatially non-flat cases exhibiting transitions from a Euclidean to a Lorentzian spacetime. We then discuss the conditions under which these signature changing so

M. Gasperini

It is pointed out that the coupling of macroscopic test masses to the gravi-dilaton background of string theory is non geodesic, in general, and cannot be parametrized by a Brans-Dicke model of scalar-tensor gravity. The response of gravitational antennas to dilatonic waves should be analyzed through a generalized equation of geodesic deviation, taking into

Banibrata Mukhopadhyay

We are familiar with Dirac equation in flat space by which we can investigate the behaviour of half-integral spin particle. With the introduction of general relativistic effects the form of the Dirac equation will be modified. For the cases of different background geometry like Kerr, Schwarzschild etc. the corresponding form of the Dirac equation as well as

S. Luding, H. J. Herrmann

When dissipative particles are left alone, their fluctuation energy decays due to collisional interactions, clusters build up and grow with time until the system size is reached. When the effective dissipation is strong enough, this may lead to the `inelastic collapse', i.e. the divergence of the collision frequency of some particles. The cluster growth

P. Barbara, F. M. Araujo-Moreira, A. B. Cawthorne, C. J. Lobb

The paramagnetic Meissner effect (PME) measured in high $T_{C}$ granular superconductors has been attributed to the presence of $π$-junctions between the grains. Here we present measurements of complex AC magnetic susceptibility from two-dimensional arrays of conventional (non $π$) Nb/Al/AlOx/Nb Josephson junctions. We measured the susceptibility as a functi

German Drazer, Horacio S. Wio, Constantino Tsallis

Recently, analytical solutions of a nonlinear Fokker-Planck equation describing anomalous diffusion with an external linear force were found using a non extensive thermostatistical Ansatz. We have extended these solutions to the case when an homogeneous absorption process is also present. Some peculiar aspects of the interrelation between the deterministic f

S. Luding, O. Strauss, S. McNamara

Granular media are examined with the focus on polydisperse mixtures in the presence of two localized heat-baths. If the two driving energies are similar, the large particles prefer to stay in the `cold' regions of the system -- as far away from the energy source as possible. If one of the temperatures is larger than the other, the cold region is shifted

S. McNamara, S. Luding

We show that a mixture of two species of granular particles with equal sizes but differing densities can be either segregated or mixed by adjusting the granular temperature gradient and the magnitude of the gravitational force. In the absence of gravity, the dense, heavy particles move to the colder regions. If the temperature gradient is put into a gravitat

Juan R. Sanchez

There are three fundamental physical processes that gives rise to the morphology of a surface: deposition, surface diffusion and desorption. The characteristics of the interfaces generated by the combination of deposition and surface diffusion has been well studied during the past decades . In particular for growth models, particles are added to the surface

G. M. Kavoulakis, C. J. Pethick, H. Smith

The damping of collective modes and the relaxation of temperature anisotropies in a trapped Bose gas is determined at temperatures above the Bose-Einstein condensation temperature in the collisionless regime. We demonstrate for both cases how the effects of collisions may be treated perturbatively and calculate relaxation rates based on a variational princip

R. Monasson, R. Zecchina, S. Kirkpatrick, B. Selman

Heuristic methods for solution of problems in the NP-Complete class of decision problems often reach exact solutions, but fail badly at "phase boundaries", across which the decision to be reached changes from almost always having one value to almost having a different value. We report an analytic solution and experimental investigations of the phase

D. Roubtsov, Y. Lepine

We explore a nonlinear field model to describe the interplay between the ability of excitons to be Bose-condensed and their interaction with other modes of a crystal. We apply our consideration to the long-living para-excitons in Cu2O. Taking into account the exciton-phonon interaction and introducing a coherent phonon part of the moving condensate, we deriv

M. Piccioni, V. Loreto, S. Roux

The dilatancy angle describes the propensity of a granular medium to dilate under an applied shear. Using a simple spin model (the ``tetris'' model) which accounts for geometrical ``frustration'' effects, we study such a dilatancy angle as a function of density. An exact mapping can be drawn with a directed percolation process which proves th

E. Caglioti, V. Loreto

We investigate the role of entropic concepts for the relaxation dynamics in granular systems. In these systems the existence of a geometrical frustration induces a drastic modification of the allowed phase space, which in its turn induces a dynamic behavior characterized by hierarchical relaxation phenomena with several time scales associated. In particular

P. Lemmens, M. Fischer, M. Grove, P. H. M. v. Loosdrecht

Many low dimensional spin systems with a dimerized or ladder-like antiferromagnetic exchange coupling have a gapped excitation spectrum with magnetic bound states within the spin gap. For spin ladders with an even number of legs the existence of spin gaps and within the t-J model a tendency toward superconductivity with d-wave symmetry is predicted. In the f

U. Zuelicke, A. H. MacDonald

We study the low-lying excitations of a quantum-Hall sample that has undergone edge reconstruction such that there exist three branches of chiral edge excitations. Among the interaction processes that involve electrons close to the three Fermi points is a new type of Umklapp-scattering process which has not been discussed before. Using bosonization and a ref

Neil F. Johnson, Michael Hart, Pak Ming Hui, Dafang Zheng

We explore various extensions of Challet and Zhang's Minority Game in an attempt to gain insight into the dynamics underlying financial markets. First we consider a heterogeneous population where individual traders employ differing `time horizons' when making predictions based on historical data. The resulting average winnings per trader is a highly

Jesper Lykke Jacobsen, Marco Picco

We numerically examine the large-q asymptotics of the q-state random bond Potts model. Special attention is paid to the parametrisation of the critical line, which is determined by combining the loop representation of the transfer matrix with Zamolodchikov's c-theorem. Asymptotically the central charge seems to behave like c(q) = 1/2 log_2(q) + O(1). Ver

M. V. Tokarchuk, I. P. Omelyan, A. E. Kobryn

We consider a new kinetic equation for systems with a multistep potential of interaction proposed by us recently in Physica A 234 (1996) 89. This potential consists of the hard sphere part and a system of attractive and repulsive walls. Such a model is a generalization of many previous semi-phenomenological kinetic theories of dense gases and liquids. In thi

Leonid Didukh, Vasyl Hankevych

In the present paper we study chemical potential of a generalized Hubbard model with correlated hopping at half-filling using a generalized mean-field approximation. For the special case of the model the approach reproduces the exact results: metal-insulator transition, ground state energy. Chemical potential of generelized Hubbard model with correlated hopp

F. M. Araujo-Moreira, C. Navau, A. Sanchez

We study the magnetic response of superconductors in the presence of low values of a uniform applied magnetic field. We report measurements of DC magnetization and AC magnetic susceptibility performed on niobium cylinders of different length-to-radius ratios, which show a dramatic enhance of the initial magnetization for thin samples, due to the demagnetizin

Ophir M. Auslaender, Shmuel Fishman

Adiabatic variation of the parameters of a chaotic system results in a fluctuating reaction force. In the leading order in the adiabaticity parameter, a dissipative force, that is present in classical mechanics was found to vanish in quantum mechanics. On the time scale t, this force is proportional to I(t), the integral of the force-force correlation functi

Martin Sieber

We investigate the influence of diffraction on the statistics of energy levels in quantum systems with a chaotic classical limit. By applying the geometrical theory of diffraction we show that diffraction on singularities of the potential can lead to modifications in semiclassical approximations for spectral statistics that persist in the semiclassical limit

Ashot Yu. Shahverdian

The paper introduces a one dimensional analogy of Poincare's "section" method. Its application to numerical study of sequences of fractional parts is considered. As a result, the possibility of Cantorian structure of time flow is deduced. A possible way of interrelating the time flow and time perception, is discussed.

K. I. Uchida, K. Sellgren, M. W. Werner, M. L. Houdashelt

We present 5-15 micron imaging spectroscopy of the reflection nebulae vdB 17 (NGC 1333), vdB 59 (NGC 2068), vdB 101, vdB 111, vdB 133 and vdB 135, obtained with the infrared camera and circular variable filter wheel on the Infrared Space Observatory (ISO). These nebulae are illuminated by stars with Teff = 3,600-19,000 K, implying ultraviolet to total stella

K. K. S. Wu, A. C. Fabian, P. E. J. Nulsen

Almost all of the extragalactic X-ray background (XRB) at 0.25 keV can be accounted for by radio-quiet quasars, allowing us to derive an upper limit of 4 \bgunit\ for the remaining background at 0.25 keV. However, the XRB from the gas halos of groups of galaxies, with gas removal due to cooling accounted for, exceeds this upper limit by an order of magnitude

S. B. Kraemer, D. M. Crenshaw, J. B. Hutchings, T. R. Gull

We have examined the physical conditions in the narrow-line region of the well-studied Seyfert galaxy NGC 4151, using long-slit spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS). The data were taken along a position angle of 221 degrees, centered on the optical nucleus. We have generated photoionization models f

Tiziana Di Matteo, Dimitrios Psaltis

We calculate upper bounds on the inner radii of geometrically thin accretion disks in galactic black-hole systems by relating their rapid variability properties to those of neutron stars. We infer that the inner disk radii do not exhibit large excursions between different spectral states, in contrast with the concept that the disk retreats significantly duri

Christopher J. Conselice

We demonstrate in this paper the use of asymmetry in conjunction with the integrated (B-V) color of galaxies for physical morphological purposes. We show how color-asymmetry diagrams can be used to distinguish between various types of galaxies, including ellipticals, late and early type disks, irregulars and interacting/merging galaxies. We also show how asy

J. P. Halpern, M. C. Eracleous

We show that unusual Balmer emission line profiles of the quasar OX 169, frequently described as either self-absorbed or double peaked, are actually neither. The effect is an illusion resulting from two coincidences. First, the forbidden lines are quite strong and broad. Consequently, the [N II]6583 line and the associated narrow-line component of H-alpha pr

M. P. Ulmer, C. Adami, R. Pildis, A. K. Romer

We have performed simulations of the effectiveness of the Serendipitous High-redshift Archival ROSAT Cluster (SHARC) survey for various model universes. We find, in agreement with work based on a preliminary set of simulations no statistically significant evolution of the luminosity function out to z = 0.8.

S. Piraino, A. Santangelo, E. C. Ford, P. Kaaret

We report the first simultaneous measurement of the broad band X-ray (0.3-150 keV) spectrum of the neutron star x-ray binary 4U0614+091. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. We dete

S. B. Popov, M. Colpi, A. Treves, R. Turolla

The paucity of old isolated accreting neutron stars in ROSAT observations is used to derive a lower limit on the mean velocity of neutron stars at birth. The secular evolution of the population is simulated following the paths of a statistical sample of stars for different values of the initial kick velocity, drawn from an isotropic Gaussian distribution wit

H. Van Winckel, M. Reyniers

We present in this paper a homogeneous photospheric abundance study, on the basis of the analysis of high resolution optical spectra, of six post-AGB objects displaying a 21mic circumstellar dust feature in their IR spectrum. The F-G spectral type of the 21mic stars make that a large range of elements including a wide variety of s-process elements, can be st

M. Hernanz, J. Jose, A. Coc, J. Gomez-Gomar

Classical novae emit gamma-ray radiation at 511 keV and below, with a cut-off at around (20-30) keV, related to positron annihilation and its Comptonization in the expanding envelope. This emission has been elusive up to now, because it occurs at epochs well before the maximum in optical luminosity, but it could be detected by some sensitive intrument on boa

Andrew R Liddle

We are on the verge of the first precision testing of the inflationary cosmology as a model for the origin of structure in the Universe. I review the key predictions of inflation which can be used as observational tests, in the sense of allowing inflation to be falsified. The most important prediction of this type is that the perturbations will cross inside

M. Arnaboldi, N. Napolitano, M. Capaccioli

Planetary Nebulae (PNe) are very important kinematical tracers of the outer regions of early-type galaxies, where the integrated light techniques fail. Under ad hoc assumptions, they allow measurements of rotation velocity and velocity dispersion profile from descrete radial velocity fields. We present the results on the precision allowed by different set of

R. Falomo, J. K. Kotilainen

We investigate the properties of the host galaxies of X-ray selected (high frequency peaked) BL Lac objects using a large and homogeneous data set of high spatial resolution R-band observations of 52 BL Lacs in the EMSS and Slew samples. The redshift distribution of the BL Lacs ranges from z = 0.04 to z>0.7, with average and median redshifts z = 0.26 and z =

Yoshiaki Sofue

Using high-accuracy rotation curves of spiral galaxies, we derive distributions of the surface mass density. Comparing with the luminosity profiles, we show that the dark mass in disk and bulge distributions follows those of luminous (stellar) mass, while luminous mass in halos does not follow dark mass. The dark-mass fraction (DMF) increases with the radius

M. Sullivan, M. A. Treyer, R. S. Ellis, T. J. Bridges

We present further spectroscopic observations for a sample of galaxies selected in the vacuum ultraviolet (UV) at 2000 Åfrom the FOCA balloon-borne imaging camera of Milliard et al. (1992). This work represents an extension of the initial study of Treyer et al. (1998). Our enlarged catalogue contains 433 sources; 273 of these are galaxies, nearly all with re

A. A. Deshpande, R. Ramachandran, V. Radhakrishnan

We examine available observations on pulsars for evidence pertaining to mechanisms proposed to explain the origin of their velocities. We find that mechanisms predicting a correlation between the rotation axis and the pulsar velocity are ruled out. Also, that there is no significant correlation between pulsar magnetic field strengths and velocities. With res

C. Sanchez Contreras, V. Bujarrabal, R. Neri, J. Alcolea

We present high-resolution observations of several molecular lines in OH231.8+4.2 taken with the IRAM interferometer. All molecules are distributed in a narrow region along the symmetry axis, and flow outwards following a velocity gradient similar to that found in CO. The HCO+ emission is found to be very clumpy and strongly enhanced in the shock-accelerated

D. Lutz, R. Genzel, E. Sturm, L. Tacconi

We report infrared spectroscopy of the prototypical Seyfert 2 galaxy NGC 1068, aiming at detection of broad components of hydrogen recombination lines that originate in the obscured broad-line region. Using the Short Wavelength Spectrometer on board the Infrared Space Observatory, we have observed for the first time the regions of Brackett beta 2.626um and P

R. G. Carlberg, H. K. C. Yee, S. L. Morris, H. Lin

The correlation evolution of a high luminosity subsample of the CNOC2 redshift survey is examined. The sample is restricted to galaxies for which the k corrected and evolution corrected R luminosity is M_R <=-20 mag, where M_* ~= -20.3 mag. This subsample contains about 2300 galaxies. In consort with 13000 galaxies in a similarly defined low redshift sample

E. L. Blanton, M. D. Gregg, D. J. Helfand, R. H. Becker

Bent-double radio sources can act as tracers for clusters of galaxies. We present imaging and spectroscopic observations of the environments surrounding ten of these sources (most of them Wide Angle Tails (WATs)) selected from the VLA FIRST survey. Our results reveal a previously unknown cluster associated with eight of the radio sources with redshifts in th

Varun Sahni, Limin Wang

We propose a new class of quintessence models in which late times oscillations of a scalar field give rise to an effective equation of state which can be negative and hence drive the observed acceleration of the universe. Our ansatz provides a unified picture of quintessence and a new form of dark matter we call &#34;Frustrated Cold Dark Matter&#34; (FCDM).

Daniel J. H. Chung, Katherine Freese

We demonstrate a non-inflationary solution to the cosmological horizon problem in scenarios in which our observable universe is confined to three spatial dimensions (a three-brane) embedded in a higher dimensional space. A signal traveling along an extra-dimensional null geodesic may leave our three-brane, travel into the extra dimensions, and subsequently r

N. A. Grogin, M. J. Geller

We assess the morphology-density relation, H-alpha linewidth-density relation, and the effects of nearby companions for 300 galaxies selected from low-density environments of the Center for Astrophysics Redshift Survey. Both the morphological mix and the EW(H-alpha) distribution of galaxies at modest underdensites are indistinguishable from our control sampl

Roman G. Mints, Vladimir G. Kogan, John R. Clem

Pancake vortices in stacks of thin superconducting films or layers are considered. It is stressed that in the absence of Josephson coupling topological restrictions upon possible configurations of vortices are removed and various examples of structures forbidden in bulk superconductors are given. In particular, it is shown that vortices may skip surface laye

Adel M. Awad, Clifford V. Johnson

We use the counterterm subtraction method to calculate the action and stress-energy-momentum tensor for the (Kerr) rotating black holes in AdS_{n+1}, for n=2, 3 and 4. We demonstrate that the expressions for the total energy for the Kerr-AdS_3 and Kerr-AdS_5 spacetimes, in the limit of vanishing black hole mass, are equal to the Casimir energies of the holog

Philip D. Mannheim

In this paper we provide both a diagnosis and resolution of the cosmological constant problem, one in which a large (as opposed to a small) cosmological constant $Λ$ can be made compatible with observation. We trace the origin of the cosmological constant problem to the assumption that the local gravitational Newton constant $G$ (as measured in a Cavendish e

Brendan Hassett, Yuri Tschinkel

Let F be a polarized irreducible holomorphic symplectic fourfold, deformation equivalent to the Hilbert scheme parametrizing length-two zero-dimensional subschemes of a K3 surface. The homology group H^2(F,Z) is equipped with an integral symmetric nondegenerate form, the Beauville form. We give precise conjectures for the structure of the cone of effective c

A. Borowiec, G. A. Vazquez Coutino

We study a coderivation from a cobimodule into a coalgebra. Vector cofields are defined by the action of a codual bicomodule on a coalgebra. This action is induced by a codifferential. A construction of a codual object in the category of bicomodules over a given coalgebra has been proposed. Various notions of duality have been analysed in this context.

Harold Steinacker

An algebra of functions on q-deformed Anti-de Sitter space AdS_q^D is defined which is covariant under U_q(so(2,D-1)), for q a root of unity. The star-structure is studied in detail. The scalar fields have an intrinsic high-energy cutoff, and arise most naturally as fields on orbifolds AdS_q^D \times S^D/G if D is odd, and AdS_q^D \times S_χ^{2D-1}/G if D is

She-Sheng Xue

In the possible scaling region for an SU(2) lattice chiral fermion advocated in {\it Nucl. Phys.} B486 (1997) 282, no hard spontaneous symmetry breaking occurs and doublers are gauge-invariantly decoupled via mixing with composite three-fermion-states that are formed by local multifermion interactions. However the strong coupling expansion breaks down due to

N. Brambilla, A. Pineda, J. Soto, A. Vairo

We compute the complete leading-log terms of the next-to-next-to-next-to-leading-order corrections to potential NRQCD. As a by-product we obtain the leading logs at $O(mα_s^5)$ in the heavy quarkonium spectrum. These leading logs, when $Λ_{QCD} \ll mα_s^2$, give the complete $O(mα_s^5 \ln α_s)$ corrections to the heavy quarkonium spectrum.

Guido Cognola, Emilio Elizalde, Sergio Zerbini

The zeta and eta-functions associated with massless and massive Dirac operators, in a D-dimensional (D odd or even) manifold without boundary, are rigorously constructed. Several mathematical subtleties involved in this process are stressed, as the intrisic ambiguity present in the definition of the associated fermion functional determinant in the massless c

Tsutomu Momoi, Keisuke Totsuka

We study the magnetization process in two-dimensional S=1/2 spin systems, to discuss the appearance of a plateau structure. The following three cases are considered: (1) the Heisenberg antiferromagnet and multiple-spin exchange model on the triangular lattice, (2) Shastry-Sutherland type lattice, [which is a possible model for SrCu2(BO3)2,] (3) 1/5-depleted

A. P. Zuker

The three main contributions to the nuclear Hamiltonian - monopole, quadrupole and pairing - are analyzed in a shell model context. The first has to be treated phenomenologically, while the other two can be reliably extracted from the realistic interactions. Due to simple scaling properties, the realistic quadrupole and pairing interactions eliminate the ten

T. Harmark, N. A. Obers

We present a general analysis of the thermodynamics of spinning black p-branes of string and M-theory. This is carried out both for the asymptotically-flat and near-horizon case, with emphasis on the latter. In particular, we use the conjectured correspondence between the near-horizon brane solutions and field theories with 16 supercharges in various dimensi

Adrian Lange, Heinz Langer, Andreas Engel

To describe the dynamics of a single peak of the Rosensweig instability a model is proposed which approximates the peak by a half-ellipsoid atop a layer of magnetic fluid. The resulting nonlinear equation for the height of the peak leads to the correct subcritical character of the bifurcation for static induction. For a time-dependent induction the effects o

N. Dupuis, V. M. Yakovenko

We study the long-wavelength collective modes in the magnetic-field-induced spin-density-wave (FISDW) phases experimentally observed in organic conductors of the Bechgaard salts family, focusing on phases that exhibit a sign reversal of the quantum Hall effect (Ribault anomaly). We have recently proposed that two SDW&#39;s coexist in the Ribault phase, as a

A. Engel, J. B. Swift

Benard-Marangoni convection in a system of two superimposed liquids is investigated theoretically. Extending previous studies the complete hydrodynamics of both layers is treated and buoyancy is consistently taken into account. The planform selection problem between rolls, squares and hexagons is investigated by explicitly calculating the coefficients of an

H. Frusawa, R. Hayakawa

To go beyond Gaussian approximation to the Hohenberg-Kohn free energy playing the key role in the density functional theory (DFT), the density functional \textit{integral} representation would be relevant, because field theoretical approach to perturbative calculations becomes available. Then the present letter first derives the associated Hamiltonian of den

M. Jinzenji

In this paper, we propose the formulas that compute all the rational structural constants of the quantum Kähler sub-ring of Fano hypersurfaces.

Rudy Wijnands, Michiel van der Klis

We report on the rapid X-ray variability of the variable star and X-ray transient V4641 Sagittarii (SAX J1819.3-2525; XTE J1819-254) as observed on 15 Sept. 1999 by the proportional counter array (PCA) on board the Rossi X-ray Timing Explorer (RXTE). During the first ~900 s of the first PCA observation, V4641 Sgr showed very strong X-ray fluctuations by a fa

Jason R. Cooke, Gerald A. Miller, Daniel R. Phillips

We study bound states in a model with scalar nucleons interacting via an exchanged scalar meson using the Hamiltonian formalism on the light front. In this approach manifest rotational invariance is broken when the Fock space is truncated. By considering an effective Hamiltonian that takes into account two meson exchanges, we find that this breaking of rotat

J. Lorenzo Diaz-Cruz, J. J. Toscano

We evaluate the lepton flavour violating (LFV) decays of HIggs bosons H->li+lj in several extensions of the SM, including both the effective lagrangian approach and several specific models. For the effective lagrangian case, we focus on dimension-six operators that induce LFV vertices for the Higgs and or Z bosons. For those operators whose coefficients can

P. H. Chankowski, W. Krolikowski, S. Pokorski

We derive the renormalization group equations for the neutrino masses and mixing angles in explicit form and discuss the possible classes of their solutions. We identify fixed points in the equations for mixing angles, which can be reached during the evolution for several mass patterns and give $\sin^22θ_{sol}=\sin^22θ_{atm}\sin^2θ_3/ (\sin^2θ_{atm}\cos^2θ_3

J. Barcelos-Neto, Alin Constandache, Ashok Das

We analyze the dispersionless limits of the Kupershmidt equation, the SUSY KdV-B equation and the SUSY KdV equation. We present the Lax description for each of these models and bring out various properties associated with them as well as discuss open questions that need to be addressed in connection with these models.

S. Prvanovic, Z. Maric, Belgrade, Serbia

The basic concepts of classical mechanics are given in the operator form. Then, the hybrid systems approach, with the operator formulation of both quantum and classical sector, is applied to the case of an ideal nonselective measurement. It is found that the dynamical equation, consisting of the Schrödinger and Liouville dynamics, produces noncausal evolutio

A. Isar

In the framework of the Lindblad theory for open quantum systems, expressions for the density operator, von Neumann entropy and effective temperature of the damped harmonic oscillator are obtained. The entropy for a state characterized by a Wigner distribution function which is Gaussian in form is found to depend only on the variance of the distribution func

H. C. Rosu

A selective chronological survey of Darboux transformations as related to supersymmetric quantum mechanics, intertwining operators and inverse scattering techniques is presented. Short comments are appended to each quotation and basic concepts are explained in order to provide a useful primer

Alexander K. Guts, Artem A. Zvyagintsev

The topos theory is a theory which is used for deciding a number of problems of theory of relativity, gravitation and quantum physics. It is known that topos-theoretic geometry can be successfully developed within the framework of Synthetic Differential Geometry of Kock-Lawvere (SDG), the models of which are serving the toposes, i.e. categories possessing ma

Tadafumi Kishimoto

We show that kaonic nuclei can be produced by the $(K^-,p)$ and $(K^-,n)$ reactions. The reactions are shown to have cross sections experimentally measurable. The observation of the kaonic nuclei gives a kaon-nucleus potential which answers the question on the existence of kaon condensation in dense nuclear matter especially neutron stars.

A. Taranenko, A. Kugler, R. Pleskac, P. Tlusty

Azimuthal distributions of $η$ and $π^{0}$ mesons emitted at midrapidity in collisions of 1.9 AGeV $^{58}$Ni+$^{58}$Ni and 2 AGeV $^{40}$Ca+$^{nat}$Ca are studied as a function of the number of projectile-like spectator nucleons. The observed anisotropy corresponds to a negative elliptic flow signal for $η$ mesons, indicating a preferred emission perpendicul

R. Golub, S. K. Lamoreaux

The Thomas-Fermi approximation for an atomic wavefunction is used to calculate the interaction of a neutron spin with the atomic electric field, either through motional magnetic (v x E) or possibly electric (due to the possible existence of a neutron permanent electric dipole moment) couplings.

Jian Zhou

We calculate the Hirzebruch $χ_y$ and $\hatχ_y$-genera of symmetric products of closed complex manifolds by the holomorphic Lefschetz formula of Atiyah and Singer \cite{Ati-Sin}. Such calculation rederive some formulas proved in an earlier paper \cite{Zho} by a different method.

Jian Zhou

For any closed complex manifold $X$, we calculate the Poincaré and Hodge polynomials of the delocalized equivariant cohomology $H^*(X^n, S_n)$ with a grading specified by physicists. As a consequence, we recover a special case of a formula for the elliptic genera of symmetric products in Dijkgraaf-Moore-Verlinde-Verlinde \cite{Dij-Moo-Ver-Ver}. For a project

Jian Zhou

We explain how to relate the problem of finding a mirror manifold for a Calabi-Yau manifold to the problem of characterizing the rational homotopy types of closed Kähler manifolds.

M. Brightwell, P. Turner

We introduce the homotopy surface category of a space which generalizes the 1+1-dimensional cobordism category of circles and surfaces to the situation where one introduces a background space. We explain how for a simply connected background space, monoidal functors from this category to vector spaces can be interpreted in terms of Frobenius algebras with ad

Dev Sinha

In this paper we compute homotopical equivariant bordism for the group ${\bf Z/2}$, namely $MO^{\bf Z/2}$, geometric equivariant bordism $Ω^{\bf Z/2}_*$, and their quotient as modules over geometric bordism. This quotient is a module of stable transversality obstructions. In doing these computations, we use the techniques the author developed in the complex

Dev Sinha

In this paper we compute homotopical bordism rings $MU^G_*$ for abelian compact Lie groups G, giving explicit generators and relations. The key constructions are operations on equivariant bordism which should play an important role in equivariant stable homotopy theory more generally. The main technique used is localization of the theory by inverting Euler c

Alan Adolphson, Steven Sperber

The method of Lagrange multipliers relates the critical points of a given function f to the critical points of an auxiliary function F. We establish a cohomological relationship between f and F and use it, in conjunction with the Eagon-Northcott complex, to compute the sum of the Milnor numbers of the critical points in certain situations.

Juan Gonzalez-Meneses

In this paper we give new presentations of the braid groups and the pure braid groups of a closed surface. We also give an algorithm to solve the word problem in these groups, using the given presentations.

Jinho Baik, Eric M. Rains

Selecting N random points in a unit square corresponds to selecting a random permutation. By putting 5 types of symmetry restrictions on the points, we obtain subsets of permutations : involutions, signed permutations and signed involutions. We are interested in the statistics of the length of the longest up/right path of random points selections in each sym

Lucian M. Ionescu

The associator of a non-associative algebra is the curvature of the Hochschild quasi-complex. The relationship ``curvature-associator&#39;&#39; is investigated. Based on this generic example, we extend the geometric language of vector fields to a purely algebraic setting, similar to the context of Gerstenhaber algebras. We interprete the elements of a non-as

Paul E. Gunnells, Robert Sczech

We define certain higher-dimensional Dedekind sums that generalize the classical Dedekind-Rademacher sums, and show how to compute them effectively using a generalization of the continued-fraction algorithm. We present two applications. First, we show how to express special values of partial zeta functions associated to totally real number fields in terms of

Chi-Keung Ng

Three natural definitions for amenability of general Hopf C^*-algebras (all of them being generalizations of the case of locally compact groups) were given and the relations between them were studied. Moreover, amenability in the situation of duality of Hopf C^*-algebras was also studied.

Michael Mueger

Given a braided tensor *-category C with conjugate (dual) objects and irreducible unit together with a full symmetric subcategory S we define a crossed product C\rtimes S. This construction yields a tensor *-category with conjugates and an irreducible unit. (A *-category is a category enriched over Vect_C with positive *-operation.) A Galois correspondence i

Alon E. Faraggi

In the first part of this paper I review the construction of the realistic free fermionic models, as well as current attempts to study aspects of these models in the nonperturbative framework of M- and F-theories. I discuss the recent demonstration of a Minimal Superstring Standard Model, which contains in the observable sector, below the string scale, solel