March 2000 arXiv papers — page 16

Luigi Grasselli, Michele Mulazzani, Roman Nedela

As previously known, all 3-manifolds of genus two can be represented by edge-coloured graphs uniquely defined by 6-tuples of integers satisfying simple conditions. The present paper describes an ``elementary transformation'' on these 6-tuples which changes the associated graph but does not change the represented manifold. This operation is a useful t

Anne Heyworth

This paper involves categories and computer science. The paper is motivated by a question which arises from two pieces of research. Firstly, the work of Brown and Heyworth which extends rewriting techniques to enable the computation of left Kan extensions over the category of sets. It is well known that left Kan extensions can be defined over categories othe

H. Ahmedov, I. H. Duru

SU(1,1) is considered as the automorphism group of the Heisenberg algebra H. The basis in the Hilbert space K of functions on H on which the irreducible representations of the group are realized is explicitly constructed. The addition theorems are derived.

Linda Chen

Hyperquot schemes are generalizations of Grothendieck's Quot scheme to partial flags. Using a Bialynicki-Birula decomposition, we obtain combinatorial data for the Betti numbers, and collect this information into the form of rational generating functions for the Poincare polynomials.

L. Andrianopoli, S. Ferrara, E. Sokatchev, B. Zupnik

We present the analysis of all possible shortenings which occur for composite gauge invariant conformal primary superfields in SU(2,2/N) invariant gauge theories. These primaries have top-spin range N/2 \leq J_{max} < N with J_{max} = J_1 + J_2, (J_1,J_2) being the SL(2,C) quantum numbers of the highest spin component of the superfield. In Harmonic superspac

G. Arutyunov, S. Frolov, S. Theisen

We study five-dimensional gravity models with non-vanishing background scalar fields which are dual to non-conformal boundary field theories. We develop a procedure to decouple the graviton fluctuations from the scalar ones and apply it to the simplest case of one scalar field. The quadratic action for the decoupled scalar fluctuations has a very simple form

Richard C. Brower, Samir D. Mathur, Chung-I Tan

We present the analysis of the complete glueball spectrum for the $AdS^7$ black hole supergravity dual of $QCD_4$ in strong coupling limit: $g^2 N \to \infty$. The bosonic fields in the supergravity multiplet lead to 6 independent wave equations contributing to glueball states with $J^{PC} = 2^{++},1^{+-}, 1^{--}$, $0^{++}$ and $0^{-+}$. We study the spectra

S. P. Gavrilov, D. M. Gitman

We revise the problem of the quantization of relativistic particle models (spinless and spinning), presenting a modified consistent canonical scheme. One of the main point of the modification is related to a principally new realization of the Hilbert space. It allows one not only to include arbitrary backgrounds in the consideration but to get in course of t

J. A. de Azcárraga, A. J. Macfarlane

We study the representation ${\cal D}$ of a simple compact Lie algebra $\g$ of rank l constructed with the aid of the hermitian Dirac matrices of a (${\rm dim} \g$)-dimensional euclidean space. The irreducible representations of $\g$ contained in ${\cal D}$ are found by providing a general construction on suitable fermionic Fock spaces. We give full details

Ruth Gregory, Valery A. Rubakov, Sergei M. Sibiryakov

In the framework of a five-dimensional model with one 3-brane and an infinite extra dimension, we discuss a process in which matter escapes from the brane and propagates into the bulk to arbitrarily large distances. An example is a decay of a particle of mass $2m$ residing on the brane into two particles of mass $m$ that leave the brane and accelerate away.

A. Mostafazadeh, K. Aghababaei Samani

We introduce the notion of a topological symmetry as a quantum mechanical symmetry involving a certain topological invariant. We obtain the underlying algebraic structure of the Z_2-graded uniform topological symmetries of type (1,1) and (2,1). This leads to a novel derivation of the algebras of supersymmetry and $p=2$ parasupersummetry.

L. M. Slad

In the paper a concept of a double symmetry is introduced, and its qualitative characteristics and rigorous definitions are given. We describe two ways to construct the double-symmetric field theories and present an example demonstrating the high efficiency of one of them. In noting the existing double-symmetric theories we draw attention at a dual status of

GianCarlo De Pol, Harvendra Singh, Mario Tonin

We perform explicitly the toroidal compactification of eleven dimensional supergravity to six dimensions and present its action in a manifestly $SO(5,5)\over SO(5)\times SO(5)$ invariant form using the recently proposed covariant formulation of theories involving chiral fields.

B. L. G. Bakker, Chueng-Ryong Ji

Naive light-front quantization, carried out by a light-front energy integration of covariant amplitudes, is not guaranteed to generate the corresponding Feynman amplitudes. In an explicit example we show that the nonvalence contribution to the minus-component of the EM current of a meson with fermion constituents has a persistent end-point singularity. Only

Eric Braaten, Yu Jia

In quantum field theory, heavy particles with mass $M$ much greater than the temperature $T$ give not only effects suppressed by the Boltzmann factor $e^{-M/T}$, but also effects suppressed by powers of $T/M$. We show that power-suppressed terms in equilibrium observables arise from effective interactions among light particles due to virtual heavy particles.

Chi-Keung Chow, Thomas D. Cohen

This is the first of two papers to study a new emergent symmetry which connects orbitally excited heavy baryons to the ground states in the combined heavy quark and large $N_c$ limit. The existence of this symmetry is shown in a model-independent way, and different possible realizations of the symmetry are discussed. It is also proved that this emergent symm

M. S. Berger

One of the useful features of muon colliders is the naturally narrow spread in beam energies. Measurements of threshold cross sections then become a prime candidate for precision measurements of particle masses, widths, and couplings as well as determining particle spin. We describe the potential for measuring cross sections near threshold in supersymmetric

Manuel Drees

I point out that the sterile neutrinos suggested as candidates of &#34;cool&#34; Dark Matter will decay through their mixing with light neutrinos. This leads to an upper bound of about 200 keV on the mass of the sterile neutrinos, but might facilitate their detection.

Hans-Christian Pauli

Taking the effective interaction between a quark and an anti-quark from previous work, the dependendence on a regularization scale is removed in line with the renormalization group. In order to emphasize the essential point, the full spinor interaction is replaced by a model which includes only the Coulomb and the hyperfine interaction. By adjusting the effe

Peter Minkowski, Wolfgang Ochs

The constituent nature of candidate gluonic mesons can be studied by comparing their production in quark and gluon jets. The production rate for such mesons depends on the colour confinement processes at the end of the perturbative evolution. Whereas we expect enhanced production of hybrids in the fragmentation region of a gluon jet, the rate for glueballs d

Craig McNeile

I describe some of the data management issues in lattice Quantum Chromodynamics calculations. I focus on the experience of the UKQCD collaboration. I describe an attempt to use a relational database to store part of the data produced by a lattice QCD calculation.

Ivan Horvath

I comment on the above paper(s) discussing the issue of non-ultralocality for Ginsparg-Wilson fermionic actions. The purpose of this note is to point out that the new claim in &#34;v3&#34; (Feb 24, 2000), alleging the proof for &#34;all Ginsparg-Wilson fermions&#34;, might not be substantiated. The remarkable evolution of versions of this paper is put in con

S. Hauswirth

We investigate an approach for the numerical solution of differential equations which is based on the perfect discretization of actions. Such perfect discretizations show up at the fixed points of renormalization group transformations. This technique of integrating out the high momentum degrees of freedom with a path integral has been mainly used in lattice

J. Llosa, D. Soler

Fermat-holonomic congruences are proposed as a weaker substitute for the too restrictive class of Born-rigid motions. The definition is expressed as a set of differential equations. Integrability conditions and Cauchy data are studied.

Piotr Jaranowski, Gerhard Schäfer

The orbital dynamics of the binary point-mass systems is ambiguous at the third post-Newtonian order of approximation. The static ambiguity is known to be related to the difference between the Brill-Lindquist solution and the Misner-Lindquist solution of the time-symmetric conformally flat initial value problem for binary black holes. The kinetic ambiguity i

A. K. Gorbatsievich

For more than 40 years E.Schmutzer has developed a new approach to the (5-dimensional) projective relativistic theory which he later called Projective Unified Field Theory (PUFT). In the present paper we introduce a new axiomatics for Schmutzer&#39;s theory. By means of this axiomatics we can give a new geometrical interpretation of the physical concept of t

Deborah East, Miroslaw Truszczynski

Answer-set programming (ASP) has emerged recently as a viable programming paradigm. We describe here an ASP system, DATALOG with constraints or DC, based on non-monotonic logic. Informally, DC theories consist of propositional clauses (constraints) and of Horn rules. The semantics is a simple and natural extension of the semantics of the propositional logic.

Stephan Busemann, Sven Schmeier, Roman G. Arens

Customer care in technical domains is increasingly based on e-mail communication, allowing for the reproduction of approved solutions. Identifying the customer&#39;s problem is often time-consuming, as the problem space changes if new products are launched. This paper describes a new approach to the classification of e-mail requests based on shallow text pro

Mary-Anne Williams, Aidan Sims

SATEN is an object-oriented web-based extraction and belief revision engine. It runs on any computer via a Java 1.1 enabled browser such as Netscape 4. SATEN performs belief revision based on the AGM approach. The extraction and belief revision reasoning engines operate on a user specified ranking of information. One of the features of SATEN is that it can b

A. B. Pakhomov, J. C. Denardin, M. Knobel, O. F. de Lima

(withdrawn)AC resistance of melt-spun granular magnetic Cu85Co15 ribbons was measured as a function of temperature in the range 5-300 K, magnetic field Hdc in the range -60 kOe to 60 kOe, and frequency in the range 1-1000 Hz. A sharp peak of zero-field resistance, which scales with frequency, and an associated isotropic giant AC magnetoresistance in small fi

Gyula Bene, Peter Szepfalusy

Corrections to the Thomas-Fermi-type solution of the Gross-Pitaevskii equation are inevitable in order to get correctly the frequencies of the low lying modes out of the Bogolyubov equations. These corrections are important in the bulk, too, thus the failure of the Thomas-Fermi approximation is not confined to the surface. We discuss this effect quantitative

S. Higashitani, K. Nagai

Effects of order parameter collective modes on electromagnetic response are studied for a clean spin-triplet superconductor with $k_x\pm ik_y$ orbital symmetry, which has been proposed as a candidate pairing symmetry for Sr$_2$RuO$_4$. It is shown that the $k_x \pm ik_y$ superconductor has characteristic massive collective modes analogous to the clapping mod

Klaus Halterman, Oriol T. Valls

We consider the Maxwell-London electrodynamics of three dimensional superconductors in p-wave pairing states with nodal points or lines in the energy gap. The current-velocity relation is then nonlinear in the applied field, cubic for point nodes and quadratic for lines. We obtain explicit angular and depth dependent expressions for measurable quantities suc

R. A. Serota

We evaluate the mean value of the van Vleck response of a two-level system with level spacing distribution and argue that it describes the orbital magnetism of small conducting particles.

Walter T. Strunz

We introduce a family of correlated trial wave functions for the $N$-particle ground state of an interacting Bose gas in a harmonic trap. For large $N$, the correlations lead to a relative energy decrease of a fraction $3/5N$, compared to mean field Gross-Pitaevskii theory. The kinetic energy in the weakly confining direction turns out to be most sensitive t

M. Marsili

We discuss a new approach to data clustering. We find that maximum likelyhood leads naturally to an Hamiltonian of Potts variables which depends on the correlation matrix and whose low temperature behavior describes the correlation structure of the data. For random, uncorrelated data sets no correlation structure emerges. On the other hand for data sets with

M. I. Marques, J. A. Gonzalo

The crossover of a pure (undiluted) Ising system (spin per site probability p=1) to a diluted Ising system (spin per site probability p<0.8) is studied by means of Monte Carlo calculations with p ranging between 1 and 0.8 at intervals of 0.025. The evolution of the self averaging is analyzed by direct determination of the normalized square widths for magneti

V. Yu. Butko, J. F. DiTusa, P. W. Adams

We present magnetoconductance (MC) measurements of homogeneously disordered Be films whose zero field sheet conductance (G) is described by the Efros-Shklovskii hopping law $G(T)=(2e^2/h)\exp{-(T_o/T)^{1/2}}$. The low field MC of the films is negative with G decreasing 200% below 1 T. In contrast the MC above 1 T is strongly positive. At 8 T, G increases 100

D. D. Sarma, E. V. Sampathkumaran, Sugata Ray, R. Nagarajan

We have prepared crystallographically ordered and disorder specimens of the double perovskite, Sr$_2$FeMoO$_6$ and investigated their magnetoresistance behaviour. The extent of ordering between the Fe and Mo sites in the two samples is determined by Rietveld analysis of powder x-ray diffraction patterns and reconfirmed by Mössbauer studies. While the ordered

Marco Bosch, Wim van Saarloos, Jan Zaanen

The stripe phases found in correlated oxides can be viewed as an ordering of the solitons associated with doping the Mott-insulating state. Inspired by the recent observation that the stripes tilt away from the main axis of the crystal lattice in the regime x = 1/8, we propose that a new type of stripe phase is realized in the large doping regime. This new p

Ph. Lambin, V. Meunier, A. Rubio

Most of the works devoted so far to the electronic band structure of multiwall nanotubes have been restricted to the case where the individual layers have the same helicity. By comparison, much less is known on the electronic properties of multiwall nanotubes that mix different helicities. These are interesting systems, however, since they can be composed of

A. V. Petukhov, A. Fasolino

We present a detailed comparison of the structural predictions of the effective many-body Brenner potential with those of ab-initio studies for known reconstructions of diamond (100) and (111) surfaces. These results suggest high reliability of the Brenner potential for dealing with carbon-based structures where different types of bonding are present at the

E. Halvorsen, Y. Galperin, K. A. Chao

We have used an eight band model to investigate the electronic structures and to calculate the optical matrix elements of InAs-GaSb broken gap semiconductor heterostructures. The unusual hybridization of the conduction band states in InAs layers with the valence band states in GaSb layers has been analyzed in details. We have studied the dependence of optica

Ping Lou, Hang-sheng Wu

A mean field SDW analysis of pseudogap in the underdoped cuprates is proposed on the basis of the $t-t^{\prime}-U$ Hubbard model. The prediction of our theory is consistent with the experiment quite well within the uncertainty of the present experimental measurement. Therefore we argue that the pseudogap phenomenon in the underdoped cuprates can be well expl

M. Mahesh Kumar, E. V. Sampathkumaran

We have investigated the magnetic and electrical resistance behaviour of Ca$_{3-x}$Y$_x$LiRuO$_6$. The parent compound exhibits magnetic ordering from Ru sublattice at a rather high temperature, 113 K. Though the paramagnetic Curie temperature ($θ$$_p$) is negative indicative of antiferromagnetic ordering, the large magnitude (-250 K) of $θ$$_p$ reveals comp

K. Hukushima, H. Kawamura

Finite-size effects in the mean-field Ising spin glass and the mean-field three-state Potts glass are investigated by Monte Carlo simulations. In the thermodynamic limit, each model is known to exhibit a continuous phase transition into the ordered state with a full and a one-step replica-symmetry breaking (RSB), respectively. In the Ising case, Binder param

Alexander N. Korotkov

We consider a two-level quantum system (qubit) which is continuously measured by a detector and calculate the spectral density of the detector output. In the weakly coupled case the spectrum exhibits a moderate peak at the frequency of quantum oscillations and a Lorentzian-shape increase of the detector noise at low frequency. With increasing coupling the sp

T. Shanks, B. J. Boyle, S. M. Croom, N. Loaring

With approximately 6000 QSO redshifts,the 2dF QSO redshift survey is already the biggest complete QSO survey. The aim for the survey is to have 25000 QSO redshifts, providing an order of magnitude increase in QSO clustering statistics. We first describe the observational parameters of the 2dF QSO survey. We then describe several highlights of the survey so f

Asantha Cooray, Wayne Hu, Jordi Miralda-Escude

Weak gravitational lensing observations probe the spectrum and evolution of density fluctuations and the cosmological parameters which govern them but are currently limited to small fields and subject to selection biases. We show how the expected signal from large-scale structure arises from the contributions from and correlations between individual halos. W

Martin D. Weinberg, Sergei Nikolaev

We derive structural parameters and evidence for extended tidal debris from star count and preliminary standard candle analyses of the Large Magellanic Cloud based on Two Micron All Sky Survey (2MASS) data. The full-sky coverage and low extinction in K_s presents an ideal sample for structural analysis of the LMC. The star count surface densities and deproje

Daniel E. Vanden Berk, Chris Stoughton, Arlin P. S. Crotts, David Tytler

We have imaged a 45x45 sq. arcmin. area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to respective limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2. The principal goals of the survey are to identify QSOs and to map structure traced by luminous galaxies and QSO absorption line systems in a wide volume containing the HD

A. Finoguenov, C. Jones

We analyzed nine X-ray bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profile and abundances of Mg, Si and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of a cooler region at the galaxy center. We present new ev

Nino Panagia, Giuseppe Bono

We present the preliminary results of a detailed theoretical investigation on the hydrodynamical properties of Red Supergiant (RSG) stars at solar chemical composition and for stellar masses ranging from 10 to 20 M_sun. We find that the main parameter governing their hydrodynamical behavior is the effective temperature, and indeed when moving from higher to

J. Binney, O. Gerhard, J. Silk

In the generic CDM cosmogony, dark-matter halos emerge too lumpy and centrally concentrated to host observed galactic disks. Moreover, disks are predicted to be smaller than those observed. We argue that the resolution of these problems may lie with a combination of the effects of protogalactic disks, which would have had a mass comparable to that of the inn

S. Serjeant, S. Oliver, M. Rowan-Robinson, H. Crockett

We present preliminary source counts at 6.7um and 15um from the Preliminary Analysis of the European Large Area ISO survey, with limiting flux densities of \~2mJy at 15um & ~1mJy at 6.7um. We separate the stellar contribution from the extragalactic using identifications with APM sources made with the likelihood ratio technique. We quantify the completeness &

Marco Chiaberge, Annalisa Celotti, Alessandro Capetti, Gabriele Ghisellini

We explore the viability of the unification of BL Lacs and FR I radio galaxies by comparing the core emission of radio galaxies with those of BL Lacs of similar extended radio power, taking advantage of the newly measured optical nuclear luminosity of FR I sources. The spectral properties of complete samples are also studied in the radio-optical luminosity p

Luis Colina, Santiago Arribas, Kirk D. Borne, Ana Monreal

Integral field optical spectroscopy with the INTEGRAL fiber-fed system and HST optical imaging are used to map the complex stellar and warm ionized gas structure in the ultraluminous infrared galaxy IRAS 12112+0305. Images reconstructed from wavelength-delimited extractions of the integral field spectra reveal that the observed ionized gas distribution is de

J. J. Binney

Both theory and observation indicate that galaxies like the Milky Way accrete matter at the rate of a few Msun per year.

A. L. B. Ribeiro, C. A. Wuensche, P. S. Letelier

We raise the hypothesis that the density fluctuations field which originates the growth of large scale structures is a combination of two or more distributions. By applying the statistical analysis of finite mixture distributions to a specific combination of Gaussian plus non-Gaussian random fields, we studied the case where just a small departure from Gauss

H. Ebeling, A. C. Edge, S. W. Allen, C. S. Crawford

We present a low-flux extension of the X-ray selected ROSAT Brightest Cluster Sample (BCS) published in Paper I of this series. Like the original BCS and employing an identical selection procedure, the BCS extension is compiled from ROSAT All-Sky Survey (RASS) data in the northern hemisphere (dec > 0 deg) and at high Galactic latitudes (|b| > 20 deg). It com

G. Cvetic

Previously developed Pade-related method of resummation for QCD observables, which achieves exact renormalization-scale-invariance, is extended so that the scheme-invariance is obtained as well. The dependence on the leading scheme parameter $c_2$ is eliminated by a variant of the method of the principle of minimal sensitivity. The subleading parameter $c_3$

L. Castellani, L. Sommovigo

We present a new class of solutions of D=10, N=2 chiral supergravity. A nonvanishing background for the field strength G_{MNR} of the complex two-form triggers AdS_3 x M_7 compactifications, where M_7 is a 7-dimensional compact manifold. When M_7 is a nonsymmetric coset space G/H, we can always find a set of constants G_{MNR} covariantly conserved and thus s

M. Cvetic, H. Lu, C. N. Pope, A. Sadrzadeh

Type IIB supergravity can be consistently truncated to the metric and the self-dual 5-form. We obtain the complete non-linear Kaluza-Klein S^5 reduction Ansatz for this theory, giving rise to gravity coupled to the fifteen Yang-Mills gauge fields of SO(6) and the twenty scalars of the coset SL(6,R)/SO(6). This provides a consistent embedding of this subsecto

C. E. Ortiz, A. Garcia, R. A. Waltz, M. Bhattacharya

The beta-delayed alpha spectrum from the decay of 8B has been measured with a setup that minimized systematic uncertainties that affected previous measurements. Consequently the deduced neutrino spectrum presents much smaller uncertainties than the previous recommendation. The 8B neutrino spectrum is found to be harder than previously recommended with about

R. Benguria, H. Castillo, M. Loewe

An elementary treatment of the Dirac Equation in the presence of a three-dimensional spherically symmetric $δ(r-r_0)$-potential is presented. We show how to handle the matching conditions in the configuration space, and discuss the occurrence of supercritical effects.

Stephan J. Huber, Michael G. Schmidt

SUSY models with a gauge singlet easily allow for a strong first order electroweak phase transition (EWPT) if the vevs of the singlet and Higgs fields are of comparable size. We discuss the profile of the stationary expanding bubble wall and CP-violation in the effective potential, in particular transitional CP-violation inside the bubble wall during the EWP

M. Novello, S. E. Perez Bergliaffa, J. M. Salim

We study here some consequences of the nonlinearities of the electromagnetic field acting as a source of Einstein&#39;s equations on the propagation of photons. We restrict to the particular case of a ``regular black hole&#39;&#39;, and show that there exist singularities in the effective geometry. These singularities may be hidden behind a horizon or naked,

Micheal S. Berger, Kim Siyeon

We show that solutions for the masses and mixings of the quarks and leptons based on a $U(1)\times Z_2$ horizontal symmetry are possible. The seesaw mechanism is shown to work consistently in the presence of the discrete symmetry. The discrete symmetry results in the phenomenologically useful suppressions of elements of the Yukawa matrices. The quark and lep

Alexander Buehler, Norbert Elstner, Goetz S. Uhrig

A computer aided high temperature expansion of the magnetic susceptibility and the magnetic specific heat is presented and demonstrated for frustrated and unfrustrated spin chains. The results are analytic in nature since the calculations are performed in the integer domain. They are provided in the form of polynomials allowing quick and easy fits. Various r

Niranjan Sambhus, S. Sridhar

The twin peaks in the nucleus of M31 have been interpreted by Tremaine as a thick, eccentric, disk of stars orbiting a massive dark object; the required alignment of the apoapsides of the stellar orbits could be maintained by self-gravity, and the whole structure might be a discrete, nonlinear eigenmode. The pattern speed of this mode could, in principle, be

Ludwik Dabrowski, Thomas Krajewski, Giovanni Landi

We introduce non-linear $σ$-models in the framework of noncommutative geometry with special emphasis on models defined on the noncommutative torus. We choose as target spaces the two point space and the circle and illustrate some characteristic features of the corresponding $σ$-models. In particular we construct a $σ$-model instanton with topological charge

D. H. Lyth

Brief review of some current topics, including gravitino creation and large extra dimensions.

D. R. Matravers, C. G. Tsagas

We discuss how a cosmological magnetic field could affect the expansion of the universe, through its interaction with the spacetime geometry. The tension of the field lines means that the magneto-curvature coupling tends to accelerate positively curved regions and decelerate those with negative curvature. Depending on the equation of state of the matter, the

Michael Gronau, Jonathan L. Rosner

The decay rates for $B^0 \to K^+ π^-$, $B^+ \to K^0 π^+$, and the charge-conjugate processes were found to provide information on the weak phase $γ\equiv {\rm Arg}(V_{ub}^*)$ when the ratio $r$ of weak tree and penguin amplitudes was taken from data on $B \to ππ$ or semileptonic $B \to π$ decays. We show here that the rates for $B_s \to K^- π^+$ and $\bar B_

Thibault Damour, Piotr Jaranowski, Gerhard Schäfer

A previously found momentum-dependent regularization ambiguity in the third post-Newtonian two point-mass Arnowitt-Deser-Misner Hamiltonian is shown to be uniquely determined by requiring global Poincaré invariance. The phase-space generators realizing the Poincaré algebra are explicitly constructed.

R. Folk, Yu. Holovatch, T. Yavors&#39;kii

Six-loop massive scheme renormalization group functions of a d=3-dimensional cubic model (J.M. Carmona, A. Pelissetto, and E. Vicari, Phys. Rev. B vol. 61, 15136 (2000)) are reconsidered by means of the pseudo-epsilon expansion. The marginal order parameter components number N_c=2.862(5) as well as critical exponents of the cubic model are obtained. Our esti

Stefan Bornholdt, Thimo Rohlf

We evolve network topology of an asymmetrically connected threshold network by a simple local rewiring rule: quiet nodes grow links, active nodes lose links. This leads to convergence of the average connectivity of the network towards the critical value $K_c =2$ in the limit of large system size $N$. How this principle could generate self-organization in nat

F. Becattini, S. Bottai

The propagation of extremely energetic nu_tau&#39;s through the Earth is studied by means of a detailed Monte Carlo simulation. All major mechanisms of nu_tau interactions and tau energy loss as well as all its relevant decay modes are properly taken into account. The detection possibility of nu_tau&#39;s emerging from Earth in forthcoming neutrino telescope

S. Groote, A. A. Pivovarov

The near threshold expansion of generalized sunset-type (water melon) diagrams with arbitrary masses is constructed by using a configuration space technique. We present analytical expressions for the expansion of the spectral density near threshold and compare it with the exact expression obtained earlier using the method of the Hankel transform. We formulat

Christos Siopis, Henry E. Kandrup

(Abridged) This paper studies chaotic orbit ensembles evolved in triaxial generalisations of the Dehnen potential which have been proposed to model ellipticals with a strong density cusp that manifest significant deviations from axisymmetry. Allowance is made for a possible supermassive black hole, as well as low amplitude friction, noise, and periodic drivi

Yu. A. Simonov

Spectrum of gluons in the adjoint source field is computed analytically using the QCD string Hamiltonian, containing only one parameter - string tension, fixed by meson and glueball spectrum. Spin splitting is shown to be small. A good agreement is observed with spatially generated gluelump states measured on the lattice. Important role of gluelumps defining

G. Oliveira-Neto

We study an analytical solution to the Einstein&#39;s equations in 2+1-dimensions. The space-time is dynamical and has a line symmetry. The matter content is a minimally coupled, massless, scalar field. Depending on the value of certain parameters, this solution represents three distinct space-times. The first one is flat space-time. Then, we have a big bang

M-R. Cioni, C. Loup, H. J. Habing, P. Fouque&#39;

We have compiled the near infrared Point Source Catalogue (PSC) towards the Magellanic Clouds (MCs) extracted from the data obtained with the Deep Near Infrared Survey of the Southern Sky - DENIS (Epchtein et al. 1997). The catalogue covers an area of of 19.87* 16 square degrees centered on (RA, DEC)=(5h27m20s, -69o00&#39;00&#39;&#39;) for the Large Magellan

Takeru Ken Suzuki, Yuzuru Yoshii, Timothy C. Beers

We have refined the estimate of the primordial level of $^7$Li abundance to an accuracy better than 10%, based on high-precision Li abundances for metal-poor halo stars, and a recent model of post-BBN (Big Bang Nucleosynthesis) chemical evolution that provides a quantitative explanation of the detected gentle ascent of the Spite Plateau for stars with metall

Brigitta von Rekowski, Axel Brandenburg, Wolfgang Dobler, Anvar Shukurov

We present an axisymmetric numerical model of a dynamo active accretion disc. If the dynamo-generated magnetic field in the disc is sufficiently strong (close to equipartition with thermal energy), a fast magneto-centrifugally driven outflow develops within a conical shell near the rotation axis, together with a slower pressure driven outflow from the outer

Igor Z. Golubchik, Vladimir V. Sokolov

Reductions for systems of ODEs integrable via the standard factorization method (the Adler-Kostant-Symes scheme) or the generalized factorization method, developed by the authors earlier, are considered. Relationships between such reductions, operator Yang-Baxter equations, and some kinds of non-associative algebras are established.

Michel Rieutord

Recently, eigenmodes of rotating fluids, namely inertial modes, have received much attention in relation to their destabilization when coupled to gravitational radiation within neutron stars. However, these modes have been known for a long time by fluid dynamicists. We give a short account of their history and review our present understanding of their proper

Manfred Requardt

We develop an alternative approach to this field, which was to a large extent developed by Verbeure et al. It is meant to complement their approach, which is largely based on a non-commutative central limit theorem and coordinate space estimates. In contrast to that we deal directly with the limits of $l$-point truncated correlation functions and show that t

Keun-Young Kim, Bum-Hoon Lee, Hyun Seok Yang

We study U(1) and U(2) instanton solutions on noncommutative R^4 based on the noncommutative version of ADHM equation proposed by Nekrasov and Schwarz. It is shown that the anti-self-dual gauge fields on self-dual noncommutative R^4 correctly give integer instanton numbers for all cases we consider. We also show that the completeness relation in the ADHM con

Donsu Bak, Sang Pyo Kim, Sung Ku Kim, Kwang-Sup Soh

We study the analytic structure of the S-matrix which is obtained from the reduced Wheeler-DeWitt wave function describing spherically symmetric gravitational collapse of massless scalar fields. The complex simple poles in the S-matrix lead to the wave functions that satisfy the same boundary condition as quasi-normal modes of a black hole, and correspond to

M. Laine, M. Losada

In many extensions of the Standard Model, finite temperature computations are complicated by a hierarchy of zero temperature mass scales, in addition to the usual thermal mass scales. We extend the standard thermal resummations to such a situation, and discuss the 2-loop computations of the Higgs effective potential, and an effective 3d field theory for the

Franck Selva, Dietmar Weinmann

A Wigner crystal structure of the electronic ground state is induced by strong Coulomb interactions at low temperature in clean or disordered two-dimensional (2d) samples. For fermions on a mesoscopic disordered 2d lattice, being closed to a torus, we study the persistent current in the regime of strong interaction at zero temperature. We perform a perturbat

A. Yu. Orlov, D. M. Scherbin

We present the q-deformed multivariate hypergeometric functions related to Schur polynomials as tau-functions of the KP and of the two-dimensional Toda lattice hierarchies. The variables of the hypergeometric functions are the higher times of those hierarchies. The discrete Toda lattice variable shifts parameters of hypergeometric functions. The role of addi

C. O. Rodriguez, Ruben Weht, W. E. Pickett

Electron-hole mixing-induced fine structure in alkaline earth hexaborides leads to lower energy (temperature) scales, and thus stronger tendency toward an excitonic instability, than in their doped counterparts (viz. Ca(1-x)La(x)B(6), x=0.005), which are high Curie temperature, small moment ferromagnets. Comparison of Fermi surfaces and spectral distribution

S. Mazumdar, R. T. Clay, D. K. Campbell

We report two surprising results regarding the nature of the spatial broken symmetries in the two-dimensional (2D), quarter-filled band with strong electron-electron interactions. First, in direct contradiction to the predictions of one-electron theory, we find a coexisting ``bond-order and charge density wave&#39;&#39; (BCDW) insulating ground state in the

Aneesh V. Manohar, Iain W. Stewart

The 1/k contribution to the heavy quark potential is first generated at one loop order in QCD. We compute the two loop anomalous dimension for this potential, and find that the renormalization group running is significant. The next-to-leading-log coefficient for the heavy quark production current near threshold is determined. The velocity renormalization gro

Bo Feng, Amihay Hanany, Yang-Hui He

Via partial resolution of Abelian orbifolds we present an algorithm for extracting a consistent set of gauge theory data for an arbitrary toric variety whose singularity a D-brane probes. As illustrative examples, we tabulate the matter content and superpotential for a D-brane living on the toric del Pezzo surfaces as well as the zeroth Hirzebruch surface. M

D. Han, Y. S. Kim, Marilyn E. Noz

It is shown that the Lorentz group is the natural language for two-beam interferometers if there are no decoherence effects. This aspect of the interferometer can be translated into six-parameter representations of the Lorentz group, as in the case of polarization optics where there are two orthogonal components of one light beam. It is shown that there are

W. M. de Muynck, A. J. A. Hendrikx

A number of atomic beam experiments, related to the Ramsey experiment and a recent experiment by Brune et al., are studied with respect to the question of complementarity. Three different procedures for obtaining information on the state of the incoming atom are compared. Positive operator-valued measures are explicitly calculated. It is demonstrated that, i

F. Popescu, A. S. Chirkin

A simple method for the production of ultrashort light pulses (USPs) with suppressed photon fluctuations is considered. The method is based on self-phase modulation (SPM) of an USP in a nonlinear medium (optical fibre) and subsequent transmission of pulse through a dispersive optical element.