May 1996 arXiv papers — page 12

Michael Frank

The two reference lists contain 54/22 references of papers and preprints concerned with the theory and/or various applications of Hilbert modules over Hilbert $*$-algebras and over (non-self-adjoint) operator algebras. They are far from being complete, but they give additional information about two research fields which are closely related to the theory of H

Michael Frank

The overview contains 450 references of books, chapters of monographs, papers, preprints and Ph.~D.~thesises which are concerned with the theory and/or various applications of Hilbert C*-modules. To show a way through this amount of literature a four pages guide is added clustering sources around major research problems and research fields, and giving inform

Edward P. Osipov

With the help of the complex structure and the wave operator of the nonlinear classical Klein-Gordon equation with the interaction $u^4_4$ we define the Wick kernel of the interacting quantum field in four-dimensional space-time and consider its properties. In particular, the diagonal of this Wick kernel is (real) solutions of the classical nonlinear Klein-G

Matthias Fuchs

The structural relaxations of a dense, binary mixture of charged hard spheres are studied using the Mode Coupling Theory (MCT). Qualitative differences to non--ionic systems are shown to result from the long--range Coulomb interaction and charge ordering in dense molten salts. The presented non--equilibrium results are determined by the equilibrium structure

D. F. Agterberg, M. B. Walker

Boundary conditions for a superconducting order parameter at a diffusive scattering boundary are derived from microscopic theory. The results indicate that for all but isotropic gap functions the diffusive boundary almost completely suppresses surface superconductivity in the Ginzburg-Landau regime. This indicates that in anisotropic superconductors surface

A. Diaz-Guilera, Alex Arenas, A. Corral, C. J. Perez

We analyze the collective behavior of a lattice model of pulse-coupled oscillators. By studying the intrinsic dynamics of each member of the population and their mutual interactions we observe the emergence of either spatio-temporal structures or synchronized regimes. We perform a linear stability analysis of these structures.

Erwin Müller-Hartmann, Elbio Dagotto

An effective electronic Hamiltonian for transition metal oxide compounds is presented. For Mn-oxides, the Hamiltonian contains spin-2 ``spins'' and spin-3/2 ``holes'' as degrees of freedom. The model is constructed from the Kondo-lattice Hamiltonian for mobile $e_g$ electrons and localized $t_{2g}$ spins, in the limit of a large Hund's co

Domenico M. Carlucci

Following the work by Houghton, Reeve and Wallace about an alternative formulation of the $n \to 0 $ limit of the $(n+1)$ state Potts model in field theory for the large order behaviour of the perturbative expansion, we generalise their technique to all $n$ by establishing an equivalence in perturbation theory order by order with another bosonic field theory

Jian-Sheng Wang, Ras B. Pandey

Using a highly efficient Monte Carlo algorithm, we are able to study the growth of coverage in a random sequential adsorption (RSA) of self-avoiding walk (SAW) chains for up to 10^{12} time steps on a square lattice. For the first time, the true jamming coverage (theta_J) is found to decay with the chain length (N) with a power-law theta_J propto N^{-0.1}. T

S. Luebeck, B. Tadic, K. D. Usadel

We introduce and study numerically a directed two-dimensional sandpile automaton with probabilistic toppling (probability parameter p) which provides a good laboratory to study both self-organized criticality and the far-from-equilibrium phase transition. In the limit p=1 our model reduces to the critical height model in which the self-organized critical beh

M. V. Simkin

Recently Mishonov (Phys. Rev. B {\bf 50}, 4009 (1994)) suggested to measure the Cooper-pair effective mass using current-induced contact potential difference in superconductors. In this Comment it is shown that actual experiments can be substantially simplified.

H. Alt, H. -D. Graef, R. Hofferbert, H. Rehfeld

We present first measurements on a superconducting three-dimensional, partly chaotic microwave billiard shaped like a small deformed cup. We analyze the statistical properties of the measured spectrum in terms of several methods originally derived for quantum systems like eigenvalue statistics and periodic orbits and obtain according to a model of Berry and

HongSheng Zhao, Shude Mao

The microlensing probability (optical depth $τ$) toward the Galactic center carries information about the mass distribution of the Galactic bulge/bar, so can be used to constrain the very uncertain shape parameters of the bar. We find $tau$ depends on the bar mass, radial profile, angle, axis scale lengths and boxyness by a few simple analytical formulae, wh

HongSheng Zhao

Motivated by the finding that the observed surface brightness profile of many galactic nuclei are well fit by double-power-laws, we explore a range of spherical self-consistent dynamical models with this light profile. We find that the corresponding deprojected volume density profile, phase space density and line-of-sight velocity distribution of these model

Jon Loveday

The Sloan Digital Sky Survey (SDSS) is a project to definitively map $π$ steradians of the local Universe. An array of CCD detectors used in drift-scan mode will digitally image the sky in five passbands to a limiting magnitude of $r' \sim 23$. Selected from the imaging survey, $10^6$ galaxies and $10^5$ quasars will be observed spectroscopically. I desc

Denise Kaisler, William E. Harris, Dennis R. Crabtree, Harvey B. Richer

We present the results of a deep photometric study of the outer halo of NGC 1275, the highly active cD galaxy at the center of the Perseus cluster. We find a modest excess of faint ($R > 22.5$) starlike objects in its halo, indicating a population of old-halo globular clusters. However, the total estimated cluster population corresponds to a specific frequen

Jon D. Pelletier

We model the ascent of warm, moist air in the Earth's atmosphere by turbulent convection and expansion with the KPZ equation, familiar in the physics literature on surface growth. Clouds form in domains where the interface between the rising air and its surrounding air achieves an elevation higher than that necessary for condensation. The model predictio

A. N. Parshin

We define and study a simplicial complex which is a homogeneous space for the group $PGL(2, K)$ over a two-dimensional local field $K$. The complex is a generalization of the tree studied by F. Bruhat, J. Tits, J.-P. Serre and P. Cartier in the 60's and early 70's. Such complex can be canonically attached to the triples $x \in C \subset X$ where $X$

J. M. Pawlowski

The effective action of a SU(N)-gauge theory coupled to fermions is evaluated at a large infrared cut-off scale k within the path integral approach. The gauge field measure includes topologically non-trivial configurations (instantons). Due to the explicit infrared regularisation there are no gauge field zero modes. The Dirac operator of instanton configurat

R. G. Carlberg, L. L. Cowie, A. Songaila, E. M. Hu

Angular and spatial correlations are measured for K-band--selected galaxies, 248 having redshifts, 54 with z>1, in two patches of combined area 27 arcmin^2. The angular correlation for K<=21.5 mag is (theta/1.4+/-0.19 arcsec e^{+/-0.1})^{-0.8}. From the redshift sample we find that the real-space correlation, calculated with q_0=0.1, of M_K<=-23.5 mag galaxi

M. A. Martin-Delgado, R. Shankar, G. Sierra

We map spin ladders with $n_l$ legs and couplings $J'$ across all rungs and $J(1 \pm \gamma)$ along the legs, staggered in both directions, to a sigma model. Setting its $\theta = (2m+1)\pi$ (where it is known to be gapless), we locate the critical curves in the $\gamma$ versus ${J'\over J}$ plane at each $n_l$, and spin $S$. The phase diagram is rich and ha

J. Lowe, B. Bassalleck, H. Burkhardt, A. Rusek

We examine a recently published calculation which predicts an oscillatory behaviour for the decay of Lambdas produced together with a neutral kaon, and proposes a new expression for the wavelength of kaon strangeness oscillations. We modify the calculation by imposing the requirement that the interference of the K_L and K_S components of the kaon wave functi

Jason X. Prochaska, Arthur M. Wolfe

We present high resolution, high SNR spectra of the QSO Q2206-199 obtained with HIRES on the 10m W.M. Keck Telescope. Our analysis focuses on the two previously identified damped \lya systems found at $z=1.920$ and $z=2.076$. For each system, we measure accurate abundances. The $z=1.920$ system exhibits the highest metallicity we have measured for a damped \

Crit Cremers, Maarten Hijzelendoorn

This paper presents a way of reducing the complexity of parsing free coordination. It lives on the Coordinative Count Invariant, a property of derivable sequences in occurrence-sensitive categorial grammar. This invariant can be exploited to cut down deterministically the search space for coordinated sentences to minimal fractions. The invariant is based on

M. Meyer-Hermann, M. Maul, L. Mankiewicz, E. Stein

An estimation of the higher twist contribution to the polarized nonsinglet structure function $g_1$ is given. Its first moment is generally assumed to be small but this could be due to a cancellation of its contribution in different Bjorken-$x$ ranges. We estimate the magnitude of $g_1^{tw4}$ as a function of $x$ in the framework of the renormalon method. Th

M. Lachieze-Rey, J. P. Luminet

General relativity does not allow one to specify the topology of space, leaving the possibility that space is multi-- rather than simply--connected. We review the main mathematical properties of multi--connected spaces, and the different tools to classify them and to analyse their properties. Following the mathematical classification, we describe the differe

She-Sheng Xue

We present the details of analyzing an $SU_L(2)\otimes U_R(1)$ chiral theory with multifermion couplings on a lattice. An existence of a possible scaling region in the phase space of multifermion couplings for defining the continuum limit of chiral fermions is advocated. In this scaling region, no spontaneous symmetry breaking occurs; the ``spectator&#39;&#3

Carlos Castro

The exact quantum integrability problem of the membrane is investigated. It is found that the spherical membrane moving in flat target spacetime backgrounds is an exact quantum integrable system for a particular class of solutions of the light-cone gauge equations of motion : a dimensionally-reduced $SU(\infty)$ Yang-Mills theory to one temporal dimension. C

I. Juhász, Zs. Nagy, Lajos Soukup, Z. Szentmiklóssy

A topological space is called P_2 ( P_3, P_{<omega} ) if and only if it does not contain two (three, finitely many) uncountable open sets with empty intersection. We show that (i) there are 0-dimensional P_{<omega} spaces of size 2^omega, (ii) there are compact P_{<omega} spaces of size omega_1, (iii) the existence of a Psi-like examples for a compact P_{<om

Gilbert Baumslag, Martin Bridson, Charles Miller, Hamish Short

We describe a general technique for embedding certain amalgamated products into direct products. This technique provides us with a way of constructing a host of finitely presented subgroups of automatic groups which are not even asynchronously automatic. We can also arrange that such subgroups satisfy, at best, an exponential isoperimetric inequality.

S. Kachru, N. Seiberg, E. Silverstein

Many N=1 heterotic string compactifications exhibit physically mysterious singularities at codimension one in the moduli space of vacua. At these singularities, Yukawa couplings of charged fields develop poles as a function of the moduli. We explain these conformal field theory singularities, in a class of examples, as arising from non-perturbative gauge dyn

Stephen L. Adler, Christian Schubert

We recalculate the amplitude for photon splitting in a strong magnetic field below the pair production threshold, using the worldline path integral variant of the Bern--Kosower formalism. Numerical comparison (using programs that we have made available for public access on the Internet) shows that the results of the recalculation are identical to the earlier

Alfredo Macías, Abel Camacho, Eckehard W. Mielke, Tonatiuh Matos

We consider an 8--dimensional gravitational theory, which possesses a principle fiber bundle structure, with Lorentz--scalar fields coupled to the metric. One of them plays the role of a Higgs field and the other one that of a dilaton field. The effective cosmological constant is interpreted as a Higgs potential. The Yukawa couplings are introduce by hand. T

Michael Green, Jeffrey A. Harvey, Gregory Moore

We show that the anomalous couplings of $D$-brane gauge and gravitational fields to Ramond-Ramond tensor potentials can be deduced by a simple anomaly inflow argument applied to intersecting $D$-branes and use this to determine the eight-form gravitational coupling.

L. Andrianopoli, M. Bertolini, A. Ceresole, R. D&#39;Auria

The general form of N=2 supergravity coupled to an arbitrary number of vector multiplets and hypermultiplets, with a generic gauging of the scalar manifold isometries is given. This extends the results already available in the literature in that we use a coordinate independent and manifestly symplectic covariant formalism which allows to cover theories diffi

D. V. Antonov

Using stochastic quantization method we derive equations for correlators of quantum fluctuations around the classical solution in the massless phi^4 theory. The obtained equations are then solved in the lowest orders of perturbation theory, and the first correction to the free propagator of a quantum fluctuation is calculated.

M. Reuter

A scale--dependent effective action for gravity is introduced and an exact nonperturbative evolution equation is derived which governs its renormalization group flow. It is invariant under general coordinate transformations and satisfies modified BRS Ward--Identities. The evolution equation is solved for a simple truncation of the space of actions. In 2+epsi

V. Davidovsky, Sh. Shvartsman

We consider the acceleration of particles (protons) in a plasma clot by an induced field which appears due to the dissolving of the clot. The mechanism of this acceleration is based on a model where the clot consists of double flat moving current layers. It is assumed that the currents flow in opposite directions, while the clot moves in a perpendicular one.

Patricia Ball

Due to its comparatively theoretical ``simplicity&#39;&#39;, the decay channel $B\toρe ν$ offers one of the best possibilities to determine the CKM matrix element $|V_{ub}|$ accurately. I present a new calculation of the relevant hadronic form factors from light-cone sum rules. I also review the results from lattice calculations and find that they agree with

M. M. Musakhanov, F. C. Khanna

The axial anomaly in the divergence of the singlet axial current in QCD $+$ QED leads to low-energy theorems for the matrix element of this operator equation over vacuum and two--photon states and for the matrix element over vacuum and two--gluon states. The solution of these theorems is related only to the nonperturbative phenomena. These matrix elements ar

J. Nemchik, N. N. Nikolaev, E. Predazzi, B. G. Zakharov

We develop the color dipole phenomenology of diffractive photo- and electroproduction $γ^{*}\,N\rightarrow V(V&#39;)\,N$ of light vector mesons ($V(1S) = ϕ^0, ω^0, ρ^0$) and their radial excitations ($V&#39;(2S) = ϕ&#39;, ω&#39;, ρ&#39;$). The node of the radial wave function of the $2S$ states in conjunction with the energy dependence of the color dipole cr

M. D. Tonasse

We study the mass spectrum and the eigenstates of the scalar sectors in 3-3-1 models. We show that, in one of the models, the physical scalar masses lead to theoretical constraints to the vacuum expectation values. The models allow very light Higgs bosons. One of the neutral scalars can be identified with the standard model one.

Thierry Grandou

We consider a scalar massless quantum field model, at finite temperature $T$, both renormalizable and asymptotically free. Focussing on the singular structure of the effective perturbation theory about the light cone, several new insights are put forth, regarding the interplay between hard thermal loop resummation and the overall compensation of collinear si

Domenico Giulini

We consider in a pedagogical fashion alterations to Newtonian gravity due to the postulate that all energy corresponds to active gravitational mass when applied to the self-energy of the gravitational field. We show why a simple addition of ${1\over c^2}$ times the gravitational field energy to the matter density in Newton&#39;s field equation is inconsisten

F. Despa, V. Topa

Diffusional interactions within the Ostwald Ripening process are analyzed in the present paper. An {\it off-centre diffusion approach \/} is performed to point out the direct correlation between the size of clusters. Herein the diffusion solution is derived as a function of both the growing and shrinking cluster sizes. Also, it is shown that the frequency tr

M. J. M. de Jong

The distribution function of transmitted charge through a double-barrier junction is studied at zero temperature and at small applied voltage. Both a semiclassical model, in which the transport is described by jump rates, and a quantum mechanical model, which averages over resonant and non-resonant states, are used to determine the characteristic function of

Steven H. Simon

When a surface acoustic wave (SAW) is coupled piezoelectrically to a two dimensional electron gas (2DEG), a velocity shift and attenuation of the SAW are induced that reflect the conductivity of the 2DEG. This paper considers the case of a AlGaAs heterostructure with a 2DEG a distance $d$ from a (100) surface of the crystal where the SAWs are propagated in t

Anton Bovier, Milos Zahradnik

We analyse the low temperature phase of ferromagnetic Kac-Ising models in dimensions $d\geq 2$. We show that if the range of interactions is $\g^{-1}$, then two disjoint translation invariant Gibbs states exist, if the inverse temperature $\b$ satisfies $\b -1\geq \g^\k$ where $\k=\frac {d(1-\e)}{(2d+1)(d+1)}$, for any $\e>0$. The prove involves the blocking

Arne Brataas, A. G. Mal&#39;shukov, Vidar Gudmundsson, K. A. Chao

We have used the Hartree-Fock Random Phase Approximation (HF-RPA) to study the interacting electron gas in a quantum wire. The spectra of intersubband spin-flip excitations reveal a considerable red shift with respect to single-particle HF energies. That signals on appearance of collective intersubband spind-density excitations due to the exchange interactio

Y. Georgelin, J. C. Wallet

We analyze the action of the inhomogeneous modular group $Γ(2)$ on the three cusps of its principal fundamental domain in the Poincare half plane. From this, we obtain an exhaustive classification of the fractional quantum Hall numbers. This classification is somehow similar to the one given by Jain. We also present some resulting remarks concerning direct p

I. L. Aleiner, L. I. Glazman

We study mesoscopic fluctuations of the conductance through a quantum dot at the wings of the Coulomb blokade peaks. At low temperatures, the main mechanism of conduction is the elastic cotunneling. The conductance strongly fluctuates with an applied magnetic field. The magnetic correlation field is shown to be controlled by the charging energy, and the corr

Michael Collins

This paper describes a new statistical parser which is based on probabilities of dependencies between head-words in the parse tree. Standard bigram probability estimation techniques are extended to calculate probabilities of dependencies between pairs of words. Tests using Wall Street Journal data show that the method performs at least as well as SPATTER (Ma

Stephan Busemann

Current work in surface realization concentrates on the use of general, abstract algorithms that interpret large, reversible grammars. Only little attention has been paid so far to the many small and simple applications that require coverage of a small sublanguage at different degrees of sophistication. The system TG/2 described in this paper can be smoothly

Tsafrir Kolatt, Tsvi Piran

We find that Gamma-ray bursts (GRBs) at the 3B catalog are correlated (at 95\% confidence level) with Abell clusters. This is the first known correlation of GRBs with any other astronomical population. It confirms the cosmological origin of GRBs. Comparison of the rich clusters auto-correlation with the cross-correlation found here suggests that \sim 26 \pm

Beverly J. Smith, P. M. Harvey

We present new high spatial resolution Kuiper Airborne Observatory 50 micron and/or 100 micron data for 11 infrared-bright galaxies. We also tabulate previously published KAO data for 11 other galaxies, along with the IRAS data for the bulges of M 31 and M 81. We find that L(FIR)/L(B) and L(FIR)/L(H) correlate with CO (1 - 0) intensity and tau(100). Galaxies

Rene A. Ong, the STACEE Collaboration

The gamma-ray energy region between 20 and 250 GeV is largely unexplored. Ground-based atmospheric Cherenkov detectors offer a possible way to explore this region, but large Cherenkov photon collection areas are needed to achieve low energy thresholds. This paper discusses the development of a Cherenkov detector using the heliostat mirrors of a solar power p

H. C. Spruit

Progress in the theory of stellar convection over the past decade is reviewed. The similarities and differences between convection in stellar envelopes and laboratory convection at high Rayleigh numbers are discussed. Direct numerical simulation of the solar surface layers, with no other input than atomic physics, the equations of hydrodynamics and radiative

R. Engel, M. A. Braun, C. Pajares, J. Ranft

The cross sections for the production of hadrons in quasi-real photon-photon collisions in proton-proton and heavy ion interactions are compared with the corresponding cross sections for central diffraction and for photon-pomeron collisions. The signatures, heavy ions or protons with only slightly changed momenta together with two large rapidity gaps and a c

C. Bachas, C. Fabre

We analyze the one-loop effective gauge-field action in $Z_2$-orbifold compactifications of type-I theory. We show how, for non-abelian group factors, the threshold effects are ultraviolet finite though given entirely by a six-dimensional field theory expression.

V. Elias, D. G. C. McKeon, V. A. Miransky, I. A. Shovkovy

The infrared dynamics in the (3+1)-dimensional supersymmetric and non-supersymmetric Nambu-Jona-Lasinio model in a constant magnetic field is studied. While at strong coupling the dynamics in these two models is essentially different, it is shown that the models become equivalent at weak coupling. In particular, at weak coupling, as the strength of the magne

Yael Karov, Shimon Edelman

We describe a method for automatic word sense disambiguation using a text corpus and a machine-readable dictionary (MRD). The method is based on word similarity and context similarity measures. Words are considered similar if they appear in similar contexts; contexts are similar if they contain similar words. The circularity of this definition is resolved by

Mico Durdevic

It is shown that every quantum principal bundle is braided, in the sense that there exists an intrinsic braid operator twisting the functions on the bundle. A detailed algebraic analysis of this operator is performed. In particular, it turns out that the braiding admits a natural extension to the level of arbitrary differential forms on the bundle. Applicati

Mico Durdevic

A construction of the noncommutative-geometric counterparts of classical classifying spaces is presented, for general compact matrix quantum structure groups. A quantum analogue of the classical concept of the classifying map is introduced and analyzed. Interrelations with the abstract algebraic theory of quantum characteristic classes are discussed. Various

Mico Durdevic

A brief exposition of the general theory of characteristic classes of quantum principal bundles is given. The theory of quantum characteristic classes incorporates ideas of classical Weil theory into the conceptual framework of non-commutative differential geometry. A purely cohomological interpretation of the Weil homomorphism is given, together with a stan

Mico Durdevic

A noncommutative-geometric generalization of the classical formalism of frame bundles is developed, incorporating into the theory of quantum principal bundles the concept of the Levi-Civita connection. The construction of a natural differential calculus on quantum principal frame bundles is presented, including the construction of the associated differential

Mico Durdevic

A differential calculus of the first order over multi-braided quantum groups is developed. In analogy with the standard theory, left/right-covariant and bicovariant differential structures are introduced and investigated. Furthermore, antipodally covariant calculi are studied. The concept of the *-structure on a multi-braided quantum group is formulated, and

E. Elizalde, M. Lygren, D. V. Vassilevich

The Laplace operator acting on antisymmetric tensor fields in a $D$--dimensional Euclidean ball is studied. Gauge-invariant local boundary conditions (absolute and relative ones, in the language of Gilkey) are considered. The eigenfuctions of the operator are found explicitly for all values of $D$. Using in a row a number of basic techniques, as Mellin trans

Ariel Zhitnitsky

We discuss a few, apparently different (but actually, tightly related) problems: 1. The relation between QCD and valence quark model, 2. The asymptotic behavior of the nonperturbative pion wave function $ψ(\k, x)$ at $x\rightarrow 0,~1, \k \rightarrow \infty$ and 3. The dimensional counting rules in the intermediate region of energy. The analysis is based on

Stefano Moretti

The complete matrix element for $e^+e^-\rightarrow b\bar b W^+W^-$ is computed at tree-level within the Minimal Supersymmetric Standard Model. Rates of interest to phenomenological analyses at the Next Linear Collider are given. In particular, we study: - $t\bar t$ production and decay $t\bar t\ar (bW^+)(\bar bW^-)$; - $ZH$ production followed by $Z\ar b\bar

George E. A. Matsas

We show that the emission of a Minkowski particle by a general class of scalar sources as described by inertial observers corresponds to either the emission or the absorption of a Rindler particle as described by uniformly accelerated observers. Our results are discussed in connection with the current controversy whether uniformly accelerated detectors radia

Ping Xu

An anologue of the Calabi invariant for Poisson manifolds is considered. For any Poisson manifold $P$, the Poisson bracket on $C^{\infty}(P)$ extends to a Lie bracket on the space $Ω^{1}(P)$ of all differential one-forms, under which the space $Z^{1}(P)$ of closed one-forms and the space $B^{1}(P)$ of exact one-forms are Lie subalgebras. These Lie algebras a

K. Kundu, D. Giri, K. Ray

The behavior of electronic states of one dimensional correlated disordered systems which are modelled by a tight binding Hamiltonian is studied analytically using the invariant measure method. The approach of Bovier is generalized to include the possibility of different site energies and nearest neighbor hopping integrals inside the correlated sites or the c

Dilek Zeynep Hakkani, Kemal Oflazer, Ilyas Cicekli

This paper describes tactical generation in Turkish, a free constituent order language, in which the order of the constituents may change according to the information structure of the sentences to be generated. In the absence of any information regarding the information structure of a sentence (i.e., topic, focus, background, etc.), the constituents of the s

A. Y. Potekhin, G. G. Pavlov, J. Ventura

High magnetic fields in neutron stars, B ~ 10^{11} - 10^{13} G, substantially modify the properties of atoms and their interaction with radiation. In particular, the photoionization cross section becomes anisotropic and strongly polarization dependent. In a number of previous works based on the adiabatic approximation the conclusion was drawn that the transv

Anatol N. Kirillov, Masatoshi Noumi

We study certain $q$-difference raising operators for Macdonald polynomials (of type $A_{n-1}$) which are originated from the $q$-difference-reflection operators introduced in our previous paper. These operators can be regarded as a $q$-difference version of the raising operators for Jack polynomials introduced by L.Lapointe and L.Vinet. As an application of

Anatol N. Kirillov, Masatoshi Noumi

We introduce certain raising and lowering operators for Macdonald polynomials (of type $A_{n-1}$) by means of Dunkl operators. The raising operators we discuss are a natural $q$-analogue of raising operators for Jack polynomials introduced by L.Lapointe and L.Vinet. As an application we prove the integrality of double Kostka coefficients. Double analog of th

D. R. Phillips, I. R. Afnan

The four-dimensional $NN-πNN$ equations are adapted to the case of scalar particles with a $ϕ^2σ$ interaction Lagrangian, and solved for energies below the $σ$-production threshold. This is achieved in the approximation where $ϕσ$ scattering is dominated by the $s$-channel $ϕ$-pole term. The importance of the removal of double-counting is investigated, and a

Hiroyuki Takata

We consider 4D quantum gravity with N-dilatons with the most general couplings. Especially, on constant dilaton and arbitrary metric background, we show the structure of the divergent terms. We show the constraint between the couplings necessary to cancel the coefficient of the square of the Wyle tensor. Next we show the N dependence of a non-renormalizable

V. M. Manuilov

It is well known that in the commutative case, i.e. for $A=C(X)$ being a commutative C*-algebra, compact selfadjoint operators acting on the Hilbert C*-module $H_A$ (= continuous families of such operators $K(x)$, $x\in X$) can be diagonalized if we pass to a bigger W*-algebra $L^\infty(X)={\bf A} \supset A$ which can be obtained from $A$ by completing it wi

Saliha Azzam

We propose an algorithm to resolve anaphors, tackling mainly the problem of intrasentential antecedents. We base our methodology on the fact that such antecedents are likely to occur in embedded sentences. Sidner&#39;s focusing mechanism is used as the basic algorithm in a more complete approach. The proposed algorithm has been tested and implemented as a pa

Gregory L. Eyink

We introduce a variational method for approximating distribution functions of dynamics with a ``Liouville operator'' $\hL,$ in terms of a {\em nonequilibrium action functional} for two independent (left and right) trial states. The method is valid for deterministic or stochastic Markov dynamics, and for stationary or time-dependent distributions. A practical

Piet Hut

The size of the core is one of the main diagnostics of the evolutionary state of a globular cluster. Much has been learned over the last few years about the behavior of the core radius during and after core collapse, under a variety of different conditions related to the presence or absence of large numbers of binaries. An overview is presented of the basic

Kevin Ingersent

In a number of systems, including certain semiconductors and unconventional superconductors, the effective density of states varies near the Fermi energy like $|E-E_F|^r$. The behavior of dilute magnetic impurities in such systems is studied using a non-perturbative renormalization-group approach. Close to particle-hole symmetry, the Kondo effect is suppress

Frederic Mila, Patrice Millet, Jacques Bonvoisin

We have performed measurements of the magnetic susceptibility of NaV$_2$O$_5$ between 2 and 400 K. The high temperature part is typical of spin 1/2 chains with a nearest--neighbour antiferromagnetic exchange integral $J$ of 529 K. We develop a model for the susceptibility of a system with finite chains to account for the low temperature part of the data, whi

P. Charlat, H. Courtois, Ph. Gandit, D. Mailly

We present an experimental study of the diffusive transport in a normal metal near a superconducting interface, showing the re-entrance of the metallic conductance at very low temperature. This new mesoscopic regime comes in when the thermal coherence length of the electron pairs exceeds the sample size. This re-entrance is suppressed by a bias voltage given

Diego A. R. Dalvit, Francisco D. Mazzitelli

We consider a scalar field theory in Minkowski spacetime and define a coarse grained Closed Time Path (CTP) effective action by integrating quantum fluctuations of wavelengths shorter than a critical value. We derive an exact CTP renormalization group equation and solve it using a derivative expansion approach. Explicit calculation is performed for the $λϕ^4

Dalibor Kekez, Dubravko Klabucar

We evaluate the $π^0γ^* \to γ$ transition form factor and $γγ$ decay widths for $π^0, η_c$ and $η_b$ treated as $q\bar{q}$ bound states in the Bethe-Salpeter formalism, incorporating the dynamical chiral symmetry breaking and the Goldstone nature of the pion. In the chiral limit, the Abelian axial anomaly is incorporated analytically in our coupled Schwinger

F. Fucito, M. Martellini, M. Zeni

Using the BF version of pure Yang-Mills, it is possible to find a covariant representation of the &#39;t Hooft magnetic flux operator. In this framework, &#39;t Hooft&#39;s pioneering work on confinement finds an explicit realization in the continuum. Employing the Abelian projection gauge we compute the expectation value of the magnetic variable and find th

K. Harayama, N. Okamura

We analyze properties of general quark mass matrices. The up and down part quark mass matrices are written in terms of six dimensionless parameters and six quark masses. It is shown that two of the former six dimensionless parameters can be chosen to be any value. Once values for these two parameters are chosen, Kobayashi-Maskawa matrix is written in terms o

Xin-Nian Wang

A pQCD-based model for parton production and equilibration in ultrarelativistic heavy-ion collisions is reviewed. The model combines pQCD processes including initial and final state radiations together with string phenomenology for nonperturbative soft processes. Nuclear effects on the initial parton production, such as multiple parton scattering and nuclear

Won Young Hwang, In Gyu Koh, Yeong Deok Han

We discuss supplementary (or hidden) variables in spin-measuring equipments in EPR-Bell experiment. This theme was considered in a Bell&#39;s later work. We generalize it. First, we show why the original supplementary variable $λ$ is not to be regarded to include supplementary variables in spin-measuring equipments (why supplementary variables should be intr

N. J. Cerf, C. Adami

An analysis of quantum measurement is presented that relies on an information-theoretic description of quantum entanglement. In a consistent quantum information theory of entanglement, entropies (uncertainties) conditional on measurement outcomes can be negative, implying that measurement can be described via unitary, entropy-conserving, interactions, while

O. Ragnisco, Yu. B. Suris

Integrable discretizations are introduced for the rational and hyperbolic spin Ruijsenaars--Schneider models. These discrete dynamical systems are demonstrated to belong to the same integrable hierarchies as their continuous--time counterparts. Explicit solutions are obtained for arbitrary flows of the hierarchies, including the discrete time ones.

Sandu Popescu, Daniel Rohrlich

Quantum mechanics permits nonlocality---both nonlocal correlations and nonlocal equations of motion---while respecting relativistic causality. Is quantum mechanics the unique theory that reconciles nonlocality and causality? We consider two models, going beyond quantum mechanics, of nonlocality---``superquantum&#34; correlations, and nonlocal ``jamming&#34;

B. Pasquini, S. Boffi

Virtual Compton scattering in the $Δ$-resonance region is considered in the case of a target nucleus. The discussion involves generalized polarizabilities and is developed for zero-spin nuclei, focusing on the new information coming from virtual Compton scattering in comparison with real Compton scattering.

R. E. Cohen, J. S. Weitz

The melting curve for MgO was obtained using molecular dynamics and a non-empirical, many-body potential. We also studied premelting effects by computing the dynamical structure factor in the crystal on approach to melting. The melting curve simulations were performed with periodic boundary conditions with cells up to 512 atoms using the ab-initio Variationa

Sakae Fuchino, Lajos Soukup

In this paper, we introduce a very weak square principle which is even weaker than the similar principle introduced by Foreman and Magidor. A characterization of this principle is given in term of sequences of elementary submodels of H(χ). This is used in turn to prove a characterization of kappa-Freese-Nation property under the very weak square principle an

H. Ishikawa, Y. Matsuo, Y. Sugawara, K. Sugiyama

We derive the BPS mass formulae of the Dirichlet branes from the Born-Infeld type action. BPS saturation is realized when the brane has the minimal volume while keeping the appropriate winding numbers. We apply the idea to two cases, type IIA superstring compactified on $T^4$ and $K3$. The result is consistent with the string duality, and the expected spectr

S. Leseduarte, August Romeo

A technique for evaluating the electromagnetic Casimir energy in situations involving spherical or circular boundaries is presented. Zeta function regularization is unambiguously used from the start and the properties of Bessel and related zeta functions are central. Nontrivial results concerning these functions are given. While part of their application agr

Stefano De Leo, Pietro Rotelli

We complete the rules of translation between standard complex quantum mechanics (CQM) and quaternionic quantum mechanics (QQM) with a complex geometry. In particular we describe how to reduce ($2n$+$1$)-dimensional complex matrices to {\em overlapping\/} ($n$+$1$)-dimensional quaternionic matrices with generalized quaternionic elements. This step resolves an