May 1999 arXiv papers — page 18

I. L. Egusquiza, J. G. Muga

We reappraise and clarify the contradictory statements found in the literature concerning the time-of-arrival operator introduced by Aharonov and Bohm in Phys. Rev. {\bf 122}, 1649 (1961). We use Naimark's dilation theorem to reproduce the generalized decomposition of unity (or POVM) from any self-adjoint extension of the operator, emphasizing a natural

Dan Solomon

Quantum field theory is assumed to be gauge invariant. It is shown that for a Dirac field the assumption of gauge invariance impacts on the way the vacuum state is defined. It is shown that the conventional definition of the vacuum state must be modified to take into account the requirements of gauge invariance.

Miloslav Znojil

Within the framework of the recently proposed formalism using non-hermitean Hamiltonians constrained merely by their PT invariance we describe a new exactly solvable family of the harmonic-oscillator-like potentials with non-equidistant spectrum. Our one-dimensional superposition of the harmonic x^2 with the centrifugal-like G/x^2 is regularized by a purely

Qiong-gui Lin

We propose a simple quantum mechanical equation for $n$ particles in two dimensions, each particle carrying electric charge and magnetic flux. Such particles appear in (2+1)-dimensional Chern-Simons field theories as charged vortex soliton solutions, where the ratio of charge to flux is a constant independent of the specific solution. As an approximation, th

B. G. Sidharth

Recent results than an assembly of Fermions below the Fermi temperature would exhibit anamolous semionic behaviour are examined in the context of assoociated magnetic fields.

K. Morawetz, M. Bonitz, V. G. Morozov, G. Röpke

The short-time dynamics of correlated systems is strongly influenced by initial correlations giving rise to an additional collision integral in the non-Markovian kinetic equation. Exact cancellation of the two integrals is found if the initial state is thermal equilibrium which is an important consistency criterion. Analytical results are given for the time

D. Kugiumtzis

The schemes for the generation of surrogate data in order to test the null hypothesis of linear stochastic process undergoing nonlinear static transform are investigated as to their consistency in representing the null hypothesis. In particular, we pinpoint some important caveats of the prominent algorithm of amplitude adjusted Fourier transform surrogates (

Andris T. Stelbovics

An adaptation of the convergent close-coupling method (CCC) to calculation of differential ionization cross sections is analyzed in the context of the Temkin-Poet model. The asymptotic scattering wave functions and the unitarity relation are given for the model. It is concluded the use of "distinguishable" electrons as proposed in the CCC model is no

M. Auzinsh

In this paper a coherent superposition of angular momentum states created by absorption of polarized light by molecules is analyzed. Attention is paid to the time evolution of wave packets representing spatial orientation of internuclear axis of diatomic molecule. Two examples are considered in detail. Molecules absorbing light in a permanent magnetic field

Deb Shankar Ray

In this article we explore the phenomena of nonequilibrium stochastic process starting from the phenomenological Brownian motion. The essential points are described in terms of Einstein's theory of Brownian motion and then the theory extended to Langevin and Fokker-Planck formalism. Then the theory is applied to barrier crossing dynamics, popularly known

G. A. Lalazissis, D. Vretenar, P. Ring

The Relativistic Hartree Bogoliubov (RHB) model is applied in the description of ground-state properties of proton-rich odd-Z nuclei in the region $53 \leq Z \leq 69$. The NL3 effective interaction is used in the mean-field Lagrangian, and pairing correlations are described by the pairing part of the finite range Gogny interaction D1S. The model predicts the

E877 Collaboration, J. Barrette

Two-proton correlation functions have been measured in Si+Pb collisions at 14.6A GeV/c and Au+Au collisions at 11.5A GeV/c by the E814/E877 collaboration. Data are compared with predictions of the transport model RQMD and the source size is inferred from this comparison. Our analysis shows that, for both reactions, the characteristic size of the system at fr

R. F. Casten, Dimitri Kusnezov, N. V. Zamfir

The study of spherical-deformed ground--state phase transitions in finite nuclei as a function of N and Z is hindered by the discrete values of the nucleon number. A resolution of the integer nucleon number problem, and evidence relating to phase transitions in finite nuclei, are discussed from the experimental point of view and interpreted within the framew

T. A. Larsson

The method of constrained Hamiltonian systems can be used to reduce Fock modules. It is applied to the Virasoro algebra, where a possibly new realization is found.

Heide Gluesing-Luerssen, Joachim Rosenthal, Paul Weiner

Multidimensional convolutional codes generalize (one dimensional) convolutional codes and they correspond under a natural duality to multidimensional systems widely studied in the systems literature.

Yu. A. Neretin

We obtain a family of matrix integrals which decompose to a product of Gamma-functions (they have some relations with S.G.Gindikin 'Beta', but generally speaking essentially differ from it). We obtain Plancherel formula for Berezin representations for all series of classical groups (for large values of parameters of representations). The Berezin repr

A. Vidras, A. Yger

Using Bochner-Martinelli type residual currents we prove some generalizations of Jacobi's Residue Formula, which allow proper polynomial maps to have `common zeroes at infinity', in projective or toric situations.

Dominic Joyce

This is the sequel to "Asymptotically Locally Euclidean metrics with holonomy SU(m)", math.AG/9905041. Let G be a subgroup of U(m), and X a resolution of C^m/G. We define a special class of Kahler metrics g on X called Quasi Asymptotically Locally Euclidean (QALE) metrics. These satisfy a complicated asymptotic condition, implying that g is asymptoti

Dominic Joyce

Let G be a nontrivial finite subgroup of U(m) acting freely on C^m - 0. Then C^m/G has an isolated quotient singularity at 0. Let X be a resolution of C^m/G, and g a Kahler metric on X. We say that g is Asymptotically Locally Euclidean (ALE) if it is asymptotic in a certain way to the Euclidean metric on C^m/G. In this paper we study Ricci-flat ALE Kahler me

Do Ngoc Diep, Nguyen Viet Hai

We demonstrate the main idea of constructing irreducible unitary representations of Lie groups by using Fedosov deformation quantization in the concrete case of the group Aff(R) of affine transformations of the real straight line. By an exact computation of the star-product and the operator $\hat{\ell}_Z$, we show that the resulting representations exhausted

Marcos Marino

We review some of the uses of Whitham hierarchies in the context of the theory of the prepotential in N=2 supersymmetric gauge theories. We focus on the structure of the contact terms in the twisted topological theory, and on the connection between Whitham hierarchies and the u-plane integrals for higher rank gauge groups, trying to put together the differen

Gustavo Dotti

Some N=1 gauge theories, including SQED and N_F=1 SQCD have the property that, for arbitrary superpotentials, all stationary points of the potential V = F+D are D-flat. For others, stationary points of V are complex gauge transformationss of D-flat configurations. As an implication, the technique to parametrize the moduli space of supersymmetric vacua in ter

C. D. Fosco, F. A. Schaposnik

We study the problem of decoupling fermion fields in 1+1 and 2+1 dimensions, in interaction with a gauge field, by performing local transformations of the fermions in the functional integral. This could always be done if singular (large) gauge transformations were allowed, since any gauge field configuration may be represented as a singular pure gauge field.

Roberto Iengo, Chuan-Jie Zhu

In this note we derive an explicit modular invariant formula for the two loop 4-point amplitude in superstring theory in terms of a multiple integral (7 complex integration variables) over the complex plane which is shown to be convergent. We consider in particular the case of the leading term for vanishing momenta of the four graviton amplitude, which would

Massimo Materassi

This paper is almost an exercise in which the Hamiltonian scheme is developed for Polyakov's classical string, by following the usual framework suggested by Dirac and Bergman for the reduction of gauge theories to their essential physical degrees of freedom. The results collected here will be useful in some forthcoming papers, where strings will be studi

German Rodrigo, Mikhail Bilenky, Arcadi Santamaria

We present a detailed description of our calculation of next-to-leading order QCD corrections to heavy quark production in e^+ e^- collisions including mass effects. In particular, we study the observables $R_3^{b\ql}$ and $D_2^{b\ql}$ in the E, EM, JADE and DURHAM jet-clustering algorithms and show how one can use these observables to obtain $m_b(m_Z)$ from

Christopher D. Carone, Richard F. Lebed

We construct a supersymmetric theory of flavor based on the discrete gauge group (D_6)^2, where D_6 describes the symmetry of a regular hexagon under proper rotations in three dimensions. The representation structure of the group allows one to distinguish the third from the lighter two generations of matter fields, so that in the symmetry limit only the top

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

In this talk, which popularizes some of our recent work, we provide novel insights into the bulk properties of light chiral quarks in a fixed Euclidean volume (e.g. lattice QCD). We show that the spontaneous breakdown of chiral symmetry results into diffusing quarks with a vacuum diffusion constant $D=2F_π^2/|<\bar{q}q>|$ $\approx 0.22$ fm, in striking analo

Pablo E. Lacentre

A description of three body tau decays with general vectorial and derivative (non-minimal) couplings is presented for experiments where the tau direction of flight is not reconstructed. The proposed interactions may be due to charged current weak dipole moment couplings and hence to structure of the $τ$ lepton. The decay distribution is expressed in terms of

F. Gangemi, G. Montagna, M. Moretti, O. Nicrosini

The processes of six-quark production with one $b\bar b$ pair are studied by means of a complete tree-level electroweak calculation. The top-quark signal is examined: the importance of electroweak backgrounds, of the order of 10% above the $t\bar t$ threshold and of about 30% of the purely electroweak signal at threshold, is further stressed by studying the

K. Fialkowski, R. Wit

We present an event-by-event analysis of the cluster structure of final multihadron states resulting from heavy ion collisions. A comparison of experimental data with the states obtained from Monte Carlo generators is shown. The analysis of the first available experimental events suggests that the method is suitable for selecting some different types of even

Edoardo Di Napoli

This is a short report of the entire work developed during the study of the possible realizations of the &#34;Top Mode&#34; Standard Model. Here it is examined the breaking of internal symmetries from another point of view showing that is possible to reproduce the gauged electroweak panorama of the traditional Standard Model in a exhaustive and selfconsisten

F. Karsch, E. Laermann, M. Oevers, P. Schmidt

It has been proposed, that the chiral continuum limit of 2-flavour QCD with Wilson fermions is brought about by a phase in which flavour and parity symmetry are broken spontaneously at finite lattice spacing. At finite temperature this phase should retract from the weak coupling limit to form 5 cusps. This scenario is studied with tree level Symanzik improve

Werner Kerler

Normality in connection with $γ_5$-hermiticity determines the basic chiral properties and rules. The Ginsparg-Wilson (GW) relation is one of the allowed constraints on the spectrum. Interrelations between features of the spectrum, the sum rule for chiral differences of real modes and contributions to the Ward identity are pointed out. The alternative chiral

Kurt Langfeld

The vortex state which arises from a projection of SU(2) to $Z_2$ gauge theory is studied at finite temperatures with a special emphasis on the deconfinement phase transition.

MEGA Collaboration, M. L. Brooks, Y. K. Chen, M. D. Cooper

An experiment has been performed to search for the muon- and electron-number non-conserving decay mu+ to e+_gamma. The upper limit for the branching ratio to be GAMMA(mu+ to e+_gamma)/GAMMA(mu+ to e+_nu_nubar) < 1.2e-11 with 90% confidence.

MASS2 Collaboration

We report here the measurements of the energy spectra of atmospheric muons and of the cosmic ray primary proton and helium nuclei in a single experiment. These were carried out using the MASS superconducting spectrometer in a balloon flight experiment in 1991. The relevance of these results to the atmospheric neutrino anomaly is emphasized. In particular, th

Rose Du, Alexander Yu. Grosberg, Toyoichi Tanaka

Monte Carlo dynamics of the lattice 48 monomers toy protein is interpreted as a random walk in an abstract (discrete) space of conformations. To test the geometry of this space, we examine the return probability $P(T)$, which is the probability to find the polymer in the native state after $T$ Monte Carlo steps, provided that it starts from the native state

Rose Du, Alexander Yu. Grosberg, Toyoichi Tanaka, Michael Rubinstein

We introduce a lattice model of glass transition in polymer globules. This model exhibits a novel scenario of ergodicity breaking in which the disjoint regions of phase space do not arise uniformly, but as small chambers whose number increases exponentially with polymer density. Chamber sizes obey power law distribution, making phase space similar to a fract

L. Pal

The methods of the probability theory have been used in order to build up a new model of hysteresis. It turns out that the reversal points of the control parameter (e. g., the magnetic field) are Markov points which determine the stochastic evolution of the process. It has been shown that the branches of the hysteresis loop are converging to fixed limit curv

B. Schmittmann, R. K. P. Zia

We present a simple, pedagogical introduction to the statistics of extreme values. Motivated by a string of record high temperatures in December 1998, we consider the distribution, averages and lifetimes for a simplified model of such ``records.&#39;&#39; Our ``data&#39;&#39; are sequences of independent random numbers all of which are generated from the sam

A. Gammal, T. Frederico, L. Tomio

In the present work, we improve a numerical method, developed to solve the Gross-Pitaevkii nonlinear Schroedinger equation. A particular scaling is used in the equation, which permits to evaluate the wave-function normalization after the numerical solution. We have a two point boundary value problem, where the second point is taken at infinity. The different

C. M. Varma

A systematic solution of a general model for Copper-Oxides reveals a line of transitions $T = T_p (x)$ for $x$, the doping away from half-filling less than a critical value, to a phase with broken time reversal and rotational symmetry but with translational symmetry preserved. The single-particle spectrum in this phase is calculated to have a gap of $d_{x^2

Alexei Vazquez, Oscar Sotolongo-Costa

The precise determination of the universality classes in self-organized critical phenomena (SOC) is still an unsolved problem. Different SOC models like sandpile, linear interface depinning, and the Barkhausen effect have been investigated independently. In the present work we demonstrate that these models can all be mapped into a linear interface depinning

A. V. Nikulov, E. Milani, G. Balestrino, V. A. Oboznov

The resistive properties of layered HTSC BiSrCaCuO in the mixed state are compared with those of thin films of conventional superconductors with weak disorders (amorphous Nb_{1-x}0_{x} films) and with strong disorders (Nb_{1-x}O_{x} films with small grain structure). The excess conductivity is considered as a function of superconducting electron density and

Mark A. Miller, Jonathan P. K. Doye, David J. Wales

The role of the potential energy landscape in determining the relaxation dynamics of model clusters is studied using a master equation. Two types of energy landscape are examined: a single funnel, as exemplified by 13-atom Morse clusters, and the double funnel landscape of the 38-atom Lennard-Jones cluster. Interwell rate constants are calculated using Rice-

V. Bruyndoncx, J. G. Rodrigo, T. Puig, L. Van Look

We investigate the nucleation of superconductivity in a uniform perpendicular magnetic field H in aluminum microsquares containing a few (2 and 4) submicron holes (antidots). The normal/superconducting phase boundary T_c(H) of these structures shows a quite different behavior in low and high fields. In the low magnetic field regime fluxoid quantization aroun

S. F. Edwards, D. V. Grinev

We give a statistical-mechanical theory of stress transmission in disordered arrays of rigid grains with perfect friction. Starting from the equations of microscopic force and torque balance we derive the fundamental equations of stress equilibrium. We illustrate the validity of our approach by solving the stress distribution of a homogeneous and isotropic a

L. Fabbian, A. Latz, R. Schilling, F. Sciortino

We present mode-coupling equations for the description of the slow dynamics observed in supercooled molecular liquids close to the glass transition. The mode-coupling theory (MCT) originally formulated to study the slow relaxation in simple atomic liquids, and then extended to the analysis of liquids composed by linear molecules, is here generalized to syste

Walter Kob, Francesco Sciortino, Piero Tartaglia

The relaxation dynamics of many disordered systems, such as structural glasses, proteins, granular materials or spin glasses, is not completely frozen even at very low temperatures. This residual motion leads to a change of the properties of the material, a process commonly called aging. Despite recent advances in the theoretical description of such aging pr

D. Meyer, T. Wegner, M. Potthoff, W. Nolting

We investigate the single-impurity Anderson model by means of the recently introduced modified perturbation theory. This approximation scheme yields reasonable results away from the symmetric case. The agreement with exactly known results for the symmetric case is checked, and results for the non-symmetric case are presented. With decreasing conduction band

C. W. Gardiner, P. Zoller

A detailed quantum kinetic master equation is developed which couples the kinetics of a trapped condensate to the vapor of non-condensed particles. This generalizes previous work which treated the vapor as being undepleted.

Jun-ichi Inoue, Tobias Brandes, Akira Shimizu

An effective bosonic Hamiltonian of $1s$ excitons with ``spin&#39;&#39; degrees of freedom in two dimension is obtained through a projection procedure, starting from a conventional electron-hole Hamiltonian ${\cal H}_{eh}$. We first demonstrate that a straightforward transformation of ${\cal H}_{eh}$ into a Hamiltonian of bosonic excitons does not give the t

Raymundo Baptista, M. S. Catalan

We report on the analysis of high-speed photometry of the dwarf-nova HS1804+67 through its outburst cycle with eclipse mapping techniques. Eclipse maps show evidences of the formation of a spiral structure in the disc at the early stages of the outburst and reveal how the disc expands during the rise until its fills most of the primary Roche lobe at maximum

Asantha R. Cooray

We present the observed relation between the cosmic microwave background (CMB) temperature decrement due to the Sunyaev-Zeldovich (SZ) effect and the X-ray luminosity of galaxy clusters. We discuss this relation in terms of the cluster properties, and show that the slope of the observed relation is in agreement with both the L-T relation based on numerical s

Beverley J. Wills

The differences among apparently diverse classes of AGN are mainly the result of viewing the central engine at different orientations, because dust, which absorbs and scatters the light, partially covers the central source, and because synchrotron emission is highly beamed along the relativistic jet. Also important are factors independent of orientation: the

Zdenka Kuncic

The observation that the extremely broad, blueshifted absorption troughs which characterize broad absorption line quasars (BALQs) occur exclusively in radio-quiet quasars (RQQs) suggests that this class of active galactic nuclei (AGN) may offer important clues to the radio-loud/radio-quiet (RL/RQ) dichotomy in quasars. Interestingly, there is also substantia

Beverley J. Wills, M. S. Brotherton, A. Laor, D. Wills

The UV to soft X-rays of luminous AGNs dominate their bolometric luminosity, driven by an accretion-powered dynamo at the center. These photons ionize the surrounding gas, thereby providing clues to fueling and exhaust. Two sets of important relationships - neither of them understood - link the continuum and gas properties. (i) Boroson & Green&#39;s `eigenve

G. I. Ogilvie

Differentially rotating, &#34;advection-dominated&#34; accretion flows are considered in which the heat generated by viscous dissipation is retained in the fluid. The equations of time-dependent quasi-spherical accretion are solved in a simplified one-dimensional model that neglects the latitudinal dependence of the flow. A self-similar solution is presented

J. C. Niemeyer, W. K. Bushe, G. R. Ruetsch

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and l

A. W. Jones

In this paper I report on the recent results obtained from the Tenerife switched beam (10 GHz to 33 GHz) experiment and Jodrell Bank 5 GHz interferometer and their predictions for foreground levels. The full data analysis and results will be presented elsewhere. It is found that free-free emission dominates above 10 GHz, whereas synchrotron emission dominate

Ralf M. Hafner, N. Wyn Evans, Walter Dehnen, James Binney

An extension of Schwarzschild&#39;s galaxy-building technique is presented that, for the first time, enables one to build Schwarzschild models with known distribution functions (DFs). The new extension makes it possible to combine a DF that depends only on classical integrals with orbits that respect non-classical integrals. With such a combination, Schwarzs

G. Dubus, K. S. Long, P. A. Charles

The most luminous X-ray source in the Local Group is associated with the nucleus of M33. This source, M33 X-8, appears modulated by ~20% over a ~106 day period, making it unlikely that the combined emission from unresolved sources could explain the otherwise persistent ~1e39 erg/s X-ray flux (Dubus et al. 1997, Hernquist et al. 1991). We present here high re

Ph. Prugniel, V. Golev, G. Maubon

In order to study the influence of the environment on the stellar population of early-type galaxies we have analyzed the relations between the density of the environment (lrho) and the residuals to the Mg2-sigma relation, R_a, and between lrho and the residuals to the Fundamental Plane, R_f. Our sample of galaxies covers the range of densities, between field

Yutaka Fujita, Fumio Takahara

Based on the two-parameter family nature of X-ray clusters of galaxies obtained in a separate paper, we discuss the formation history of clusters and cosmological parameters of the universe. Utilizing the spherical collapse model of cluster formation, and assuming that the cluster X-ray core radius is proportional to the virial radius at the time of the clus

Yutaka Fujita, Fumio Takahara

We analyze the relations among central gas density, core radius, and temperature of X-ray clusters by plotting the observational data in the three-dimensional ($\log ρ_0$, $\log R$, and $\log T$) space and find that the data lie on a &#39;fundamental plane&#39;. Its existence implies that the clusters form a two-parameter family. The data on the plane still

S. J. Melhuish, S. Dicker, R. D. Davies, C. M. Gutierrez

We describe a new high sensitivity experiment for observing cosmic microwave background (CMB) anisotropies. The instrument is a 2-element interferometer operating at 33 GHz with a ~3 GHz bandwidth. It is installed on the high and dry Teide Observatory site on Tenerife where successful beam-switching observations have been made at this frequency. Two realizat

Paul J. Francis, Beverley J. Wills

Understanding the inverse equivalent width - luminosity relationship (Baldwin Effect), the topic of this meeting, requires extracting information on continuum and emission line parameters from samples of AGN. We wish to discover whether, and how, different subsets of measured parameters may correlate with each other. This general problem is the domain of Pri

Aleksey Polishchuk

The two-point Green function of a local operator in CFT corresponding to a massive symmetric tensor field on the AdS background is computed in the framework of the AdS/CFT correspondence. The obtained two-point function is shown to coincide with the two-point function of the graviton in the limit when the mass vanishes.

R. Schelp

Recent indications of neutrino oscillations raise the question of the possibility of incorporating massive neutrinos in the formulation of the Standard Model (SM) within noncommutative geometry (NCG). We find that the NCG requirement of Poincare duality constrains the numbers of massless quarks and neutrinos to be unequal unless new fermions are introduced.

Maya Paczuski, Kevin E. Bassler, Alvaro Corral

A model of Boolean agents competing in a market is presented where each agent bases his action on information obtained from a small group of other agents. The agents play a competitive game that rewards those in the minority. After a long time interval, the poorest player&#39;s strategy is changed randomly, and the process is repeated. Eventually the network

Thomas Papenbrock

We investigate the interplay of collective and chaotic motion in a classical self-bound N-body system with two-body interactions. This system displays a hierarchy of three well separated time scales that govern the onset of chaos, damping of collective motion and equilibration. Comparison with a mean-field problem shows that damping is mainly due to dephasin

Gilvan A. Alves

Hard diffraction in events with dijets and rapidity gaps has been studied by D\O and CDF for three processes: hard color singlet exchange, hard single diffraction, and hard double pomeron exchange, using Tevatron $\bar pp$ data at $\sqrt{s}$ = 630 GeV and 1.8 TeV. Measurements of rates, $\eta, E_T$ and $\sqrt{s}$ dependencies are presented and comparisons ma

J. L. Alonso, L. A. Fernandez, V. Martin-Mayor

We study the linear response to an external electric field of a system of fermions in a lattice at zero temperature. This allows to measure numerically the Euclidean conductivity which turns out to be compatible with an analytical calculation for free fermions. The numerical method is generalizable to systems with dynamical interactions where no analytical a

Massimo Campostrini, Andrea Pelissetto, Paolo Rossi, Ettore Vicari

High-temperature series are computed for a generalized $3d$ Ising model with arbitrary potential. Two specific ``improved&#39;&#39; potentials (suppressing leading scaling corrections) are selected by Monte Carlo computation. Critical exponents are extracted from high-temperature series specialized to improved potentials, achieving high accuracy; our best es

Stephan Narison

I extract the strange-quark mass using a $τ$-like decay sum rule for the $ϕ$-meson, and some other sum rules involving its difference with the vector component of the hadronic $τ$-decay. As a conservative estimate, one obtains to order $α_s^3$: $\bar{m}_s$(1 GeV) = $(178\pm 33)$ MeV $\lrar \~\bar{m}_s$(2 GeV) = $(129\pm 24)$ MeV, while the positivity of the

Seth A. Major

Spin networks, essentially labeled graphs, are ``good quantum numbers&#39;&#39; for the quantum theory of geometry. These structures encompass a diverse range of techniques which may be used in the quantum mechanics of finite dimensional systems, gauge theory, and knot theory. Though accessible to undergraduates, spin network techniques are buried in more co

Seth A. Major

Inspired by the spin geometry theorem, two operators are defined which measure angles in the quantum theory of geometry. One operator assigns a discrete angle to every pair of surfaces passing through a single vertex of a spin network. This operator, which is effectively the cosine of an angle, is defined via a scalar product density operator and the area op

B. M. Brown, E. B. Davies, P. K. Jimack, M. D. Mihajlovi'c

This paper is concerned with the accurate numerical approximation of the spectral properties of the biharmonic operator on various domains in two dimensions. A number of analytic results concerning the eigenfunctions of this operator are summarized and their implications for numerical approximation are discussed. In particular, the asymptotic behaviour of th

Johannes Berg, Martin Weigt

We use techniques from the statistical mechanics of disordered systems to analyse the properties of Nash equilibria of bimatrix games with large random payoff matrices. By means of an annealed bound, we calculate their number and analyse the properties of typical Nash equilibria, which are exponentially dominant in number. We find that a randomly chosen equi

Tsuguhiko Asakawa, Taichiro Kugo, Tomohiko Takahashi

We calculate one-loop 2-point tachyon amplitudes in unoriented open-closed string field theory, and determine all the coupling constants of the interaction vertices in the theory. It is shown that the planar, nonplanar and nonorientable amplitudes are all reproduced correctly, and nontrivial consistencies between the determined coupling constants are observe

K. I. Gus&#39;kov

The symmetrized contribution of E-type spin-rotation interaction to conversion between spin modifications of E- and A_1-types in molecules with C_{3v}-symmetry is considered. Using the high-J descending of collisional broadening for accidental rotational resonances between these spin modifications, it was possible to co-ordinate the theoretical description o

A. W. Whinnett, Diego F. Torres

We study charged boson stars in scalar-tensor (ST) gravitational theories. We analyse the weak field limit of the solutions and analytically show that there is a maximum charge to mass ratio for the bosons above which the weak field solutions are not stable. This charge limit can be greater than the GR limit for a wide class of ST theories. We numerically in

Yoichi Ando, A. N. Lavrov, Kouji Segawa

We report novel features in the in-plane magnetoresistance (MR) of heavily underdoped YBa_2Cu_3O_{6+x}, which unveil a developed ``charged stripe&#39;&#39; structure in this system. One of the striking features is an anisotropy of the MR with a &#34;d-wave&#34; symmetry upon rotating the magnetic field H within the ab plane, which is caused by the rotation o

Lars Petter Endresen

We give an algorithm for efficient step size control in numerical integration of non-stiff initial value problems, based on a formula tailormade to methods where the numerical solution is compared with a solution of lower order.

Takafumi Kita

Based on the Ginzburg-Landau functional of E_{u} symmetry presented by Agterberg, vortex states of Sr_{2}RuO_{4} are studied in detail over $H_{c1}\lesssim H \leq H_{c2}$ by using the Landau-level expansion method. For the field in the basal plane, it is found that (i) the second superconducting transition should be present irrespective of the field directio

Myung Gyoon Lee, Antonio Aparicio, Nikolay Tikonov, Yong-Ik Byun

We present deep BVI CCD photometry of the stars in the dwarf galaxy DDO 210. The color-magnitude diagrams of DDO 210 show a well-defined red giant branch (RGB) and a blue plume. The tip of the RGB is found to be at I_TRGB = 20.95 +/- 0.10 mag. From this the distance to DDO 210 is estimated to be d = 950 +/- 50 kpc. The corresponding distance of DDO 210 to th

Sadayoshi Toh, Tomoaki Itano

The instability of a streak and its nonlinear evolution are investigated by direct numerical simulation (DNS) for plane Poiseuille flow at Re=3000. It is suggested that there exists a traveling-wave solution (TWS). The TWS is localized around one of the two walls and notably resemble to the coherent structures observed in experiments and DNS so far. The phas

F. D. R. Bonnet, P. O. Bowman, D. B. Leinweber, A. G. Williams

Lattice discretisation errors in the Landau gauge condition are examined. An improved gauge fixing algorithm in which ${\cal O}(a^2)$ errors are removed is presented. ${\cal O}(a^2)$ improvement of the gauge fixing condition improves comparison with continuum Landau gauge in two ways: 1) through the elimination of ${\cal O}(a^2)$ errors and 2) through a seco

Kevin K. Lehmann

This paper presents an analysis of the motion of an neutral impurity species in a nanometer scale $^4$He cluster, extending a previous study of the dynamics of an ionic impurity. It is shown that for realistic neutral impurity-He potentials, such as those of SF$_6$ and OCS, the impurity is kept well away of the the surface of the cluster by long range induct

H. Blas, B. M. Pimentel

The conformal affine sl(2) Toda model coupled to matter field is treated as a constrained system in the context of Faddeev-Jackiw and the (constrained) symplectic schemes. We recover from this theory either, the sine-Gordon or the massive Thirring model, through a process of Hamiltonian reduction, considering the equivalence of the Noether and topological cu

S. W. Allen, T. Di Matteo, A. C. Fabian

We report the detection of hard X-ray emission components in the spectra of six nearby, giant elliptical galaxies observed with the ASCA satellite. The systems studied, which exhibit strong dynamical evidence for supermassive black holes in their nuclei, are M87, NGC 1399 and NGC 4696 (the dominant galaxies of the Virgo, Fornax and Centaurus clusters, respec

T. Tsuchida, M. Wadati

The Lax pair for a derivative nonlinear Schrödinger equation proposed by Chen-Lee-Liu is generalized into matrix form. This gives new types of integrable coupled derivative nonlinear Schrödinger equations. By virtue of a gauge transformation, a new multi-component extension of a derivative nonlinear Schrödinger equation proposed by Kaup-Newell is also obtain

Alexander Turbiner, Pavel Winternitz

Matrix Riccati equations and other nonlinear ordinary differential equations with superposition formulas are, in the case of constant coefficients, shown to have the same exact solutions as their group theoretical discretizations. Explicit solutions of certain classes of scalar and matrix Riccati equations are presented as an illustration of the general resu

N. Gisin, B. Gisin

A local hidden variable model exploiting the detection loophole to reproduce exactly the quantum correlation of the singlet state is presented. The model is shown to be compatible with both the CHSH and the CH Bell inequalities. Moreover, it bears the same rotational symmetry as spins. The reason why the model can reproduce the quantum correlation without vi

P. Facchi, S. Pascazio

The quantum &#34;Zeno&#34; time of the 2P-1S transition of the hydrogen atom is computed and found to be approximately 3.59 10^{-15}s (the lifetime is approximately 1.595 10^{-9}s). The temporal behavior of this system is analyzed in a purely quantum field theoretical framework and is compared to the exponential decay law.

M. Auzinsh, R. Damburg

A simple expression for a ground state energy for a two-electron atom is derived. For this, assumption based upon the Niels Bohr &#39;&#39;old&#39;&#39; quantum mechanics idea about electron correlation in a two-electron atom is exploited. Results are compared with experimental data and theoretical results based on a variation approach.

Oscar Bolina

We discuss how a class of difficult kinematic problems can play an important role in an introductory course in stimulating students&#39; reasoning on more complex physical situations. The problems presented here have an elementary analysis once certain symmetry features of the motion are revealed. We also explore some unexpected directions these problems lea

Oscar Bolina

We show how some geometric elements of the path of a particle moving in a plane -- the osculating circle and its radius of curvature -- can be used to construct the parabolic trajectory of projectiles in motion under gravity.

A. F. Borghesani, F. Tamburini

The drift mobility of the negative oxygen ion in dense Argon gas near the liquid-vapor critical point has been measured as a function of the density. Near the critical temperature the zero-field density-normalized ion mobility shows a deep minimum at a density smaller than the critical one. This phenomenon was previously intepreted as the result of the forma