bluuebunny/crossref_metadata_2025 huggingface dataset:
A NONSTANDARD TRIPLE GLUON DECAY
Authors: LI XIN-ZHOU , ZHANG JIAN-ZU
Published: November 2004

In this letter we show a nonstandard decay of technion P0′ into three gluons in Wess–Zumino-type effective action in the technicolor scheme. The implication of this new anomaly gauge boson production process is discussed.
NEW SOLUTION OF VERTEX TYPE TETRAHEDRON EQUATIONS
Authors: MANGAZEEV V. V. , SERGEEV S. M. , STROGANOV YU. G.
Published: November 2004

In this letter we formulate a new N-state spin integrable model on a three-dimensional lattice with spins interacting round each elementary cube of the lattice. This model can also be reformulated as a vertex type model. Weight functions of the model satisfy tetrahedron equations.
GENERALIZED W3-STRINGS FROM FREE FIELDS
Authors: FIGUEROA-O'FARRILL J. M. , HULL C. M. , PALACIOS L. , RAMOS E.
Published: November 2004

The conventional quantization of w3-strings gives theories which are equivalent to special cases of bosonic strings. We explore whether a more general quantization can lead to new generalized W3-string theories by seeking to construct quantum BRST charges directly without requiring the existence of a quantum W3-algebra. We study W3-like strings with a direct space-time interpretation — that is, with matter given by explicit free field realizations. Special emphasis is placed on the attempt to construct a quantum W-string associated with the magic realizations of the classical w3-algebra. We give the general conditions for the existence of W3-like strings, and comment on how the known results fit into our general construction. Our results are negative: we find no new consistent string theories, and in particular rule out the possibility of critical strings based on the magic realizations.
GRAVITATIONAL SELF-ENERGY AS THE LITMUS OF REALITY
Authors: JONES K. R. W.
Published: November 2004

It is argued that the correct physical treatment of self-energy in Newtonian quantum gravity offers a constrained and predictive discriminator for the interpretation of ψ, and thus a clear point of departure for the unification of modern physics.
q-OSCILLATORS, NON-KÄHLER MANIFOLDS AND CONSTRAINED DYNAMICS
Authors: SHABANOV SERGEI V.
Published: November 2004

It is shown that q-deformed quantum mechanics (systems with q-deformed Heisenberg commutation relations) can be interpreted as an ordinary quantum mechanics on Kähler manifolds, or as a quantum theory with second- (or first-) class constraints.
EXACT PARTITION FUNCTION AND BOUNDARY STATE OF CRITICAL ISING MODEL WITH BOUNDARY MAGNETIC FIELD
Authors: CHATTERJEE R.
Published: November 2004

We compute the exact partition function of the 2-D Ising Model at critical temperature but with nonzero magnetic field at the boundary. The model describes a renormalization group flow between the free and fixed conformal boundary conditions in the space of boundary interactions. For this flow the universal ground state degeneracy g and the full boundary state is computed exactly.
NEW PARTICLE SEARCHES HAUNTED BY VIRTUAL LIGHTEST SUPERSYMMETRIC PARTICLES
Authors: DATTA AMITAVA , GUCHHAIT MONORANJAN , MUKHOPADHYAYA BISWARUP
Published: November 2004

Relatively light sneutrinos which are experimentally allowed but not favored theoretically, may significantly affect the currently popular search strategies for supersymmetric particles by decaying predominantly into an invisible channel. In such cases the second lightest neutralino also becomes invisible. Consequences of such scenario in connection with the ongoing searches at the Tevatron and LEP-II are discussed.
ELECTRIC QUADRUPOLE MOMENTS OF THE DECUPLET BARYONS IN THE SKYRME MODEL
Authors: OH YONGSEOK
Published: November 2004

We calculate the electric quadrupole moments of the decuplet baryons in the bound state approach of the Skyrme model. In this approach, all the quadrupole moments of the decuplets are proportional to the third component of the baryon isospin. Contrary to the SU(3) collective model, the kaonic contribution is as important as the pionic one. The transitional quadrupole moments of the hyperons are also predicted.
SEMILEPTONIC B→D(*)lν DECAYS, THE SLOPE OF ISGUR-WISE FUNCTION AND |Vbc| VALUE IN POTENTIAL QUARK MODEL
Authors: KISELEV V.V.
Published: November 2004

The modification of the naive potential model of the heavy meson is considered on the basis of the single-time prescription for the quark-meson form factor and the covariant choice of the quark relative momentum. The application of the model to the description of the semileptonic decays of the beauty meson allows one to determine the Isgur-Wise function slope ρ2≃0.94 and to extract the value |Vbc|=0.036±0.002 from the experimental data.
LIMITS ON EXTENSIONS OF THE MINIMAL STANDARD MODEL FROM COMBINED LEP LINESHAPE DATA
Authors: SOPCZAK ANDRÉ
Published: November 2004

The high statistics of the combined LEP lineshape data are used to derive constraints on hypothetical extensions of the minimal standard model. The data comprises about eight million visible Z decays, recorded between 1989 and 1993. This letter gives limits for simple tests on models which predict additional Z boson decays or modified Z-couplings. As an application, the two-doublet Higgs model is considered.
NEUTRALINO EVENT RATES IN DARK MATTER DETECTORS
Authors: ARNOWITT R. , NATH PRAN
Published: November 2004

The expected event rates for [Formula: see text] dark matter for supergravity grand unified models are studied for a variety of dark matter detectors over the parameter space with tan β≤20 and a range of gluino masses where the maximum event rate can at least approach 10−2 event/kg.da. This is the maximum sensitivity that the dark matter detectors can hope to achieve in the forseeable future. Radiative breaking constraints are implemented and effects of the heavy neutral Higgs as well as loop corrections to the neutral Higgs sector are included. The parameter space is further restricted so that the [Formula: see text] relic density obeys the CHDM constraint [Formula: see text], consistent with the COBE data and astronomical determinations of the Hubble constant. It is found that the best detectors sensitive to coherent [Formula: see text] scattering (e.g. Pb) are about 5–10 times more sensitive than those based on incoherent spin-dependent scattering (e.g. CaF). In general, the dark matter detectors are most sensitive to the large tan β and small m0 and [Formula: see text] sectors of the parameter space.
ANISOTROPIC AFFINE ALGEBRA AND ANISOTROPIC WZW MODEL
Authors: MUKHOPADHYAY INDRANIL , CHOWDHURY A. ROY
Published: November 2004

Invariant action for a new kind of (anisotropic) WZW model has been constructed using the co-adjoint orbit approach and the affine anistropic algebra suggested by Sidorenko. The Alekseev-Shatashvili type of equation is used to construct the corresponding symplectic form. The present model is similar in many aspects to the WZW model on a Riemann surface.
A COMPLEMENT TO GOLDSTEIN-MORAVCSIK THEOREM
Authors: DEVI A.R. USHA , RAO A. SUDHA , RAMACHANDRAN G.
Published: November 2004

As a complement to Goldstein-Moravcsik theorem, we show that in parity conserving reactions with spin structure 0+1/2→1+1/2 the differential cross-section [Formula: see text] and the vector polarization [Formula: see text] of spin-one particle are sufficient to determine the amplitudes unambiguously and there is no need to measure the tensor polarization [Formula: see text].
GENERAL DILATONIC GRAVITY WITH AN ASYMPTOTICALLY FREE GRAVITATIONAL COUPLING CONSTANT NEAR TWO DIMENSIONS
Authors: ELIZALDE E. , ODINTSOV S.D.
Published: November 2004

We study a renormalizable, general theory of dilatonic gravity (with a kinetic-like term for the dilaton) interacting with scalar matter near two dimensions. The one-loop effective action and the beta functions for this general theory are written down. It is proven that the theory possesses a nontrivial uv fixed point which yields an asymptotically free gravitational coupling constant (at ε→0) in this regime. Moreover, at the fixed point the theory can be cast under the form of a string-inspired model with free scalar matter. The renormalization of the Jackiw-Teitelboim model and of lineal gravity in 2+ε dimensions is also discussed. We show that these two theories are distinguished at the quantum level. Finally, fermion-dilatonic gravity near two dimensions is considered.
MULTI-INSTANTON EFFECT IN TWO-DIMENSIONAL QCD
Authors: OCHIAI TETSUYUKI
Published: November 2004

We analyze multi-instanton sector in two-dimensional U(N) Yang-Mills theory on a sphere. We obtain a contour integral representation of the multi-instanton amplitude and find “neutral” configurations of the even number instantons dominate in the large-N limit. Using this representation, we calculate the 1-, 2-, 3-, 4-body interactions and the free energies for N=3, 4, 5 numerically and find that the multi-instanton interaction effect essentially contributes to the large-N phase transition discovered by Douglas and Kazakov.
INSTANTONS IN THE STOCHASTIC QCD VACUUM
Authors: AGASYAN N.O. , SIMONOV YU.A.
Published: November 2004

Instantons in the stochastic confining background are influenced by both the oneloop renormalization in the background and a direct interaction with the background. Stochasticity (finite correlation length) of the background drastically changes the ir properties and yields a convergent instanton density even neglecting interinstanton interaction, while the packing parameter (ρ/R)4 decreases due to the background.
APPROXIMATE FLAVOR SYMMETRIES AND SEESAW MECHANISM
Authors: LEE KANG YOUNG
Published: November 2004

We study the approximate flavor symmetries imposed on the lepton sector assuming seesaw mechanism as the neutrino mass structure. We apply the symmetry to various neutrino phenomenologies and obtain constraints on neutrino masses and mixings.
THE INTERNAL MOTION OF SUPERPARTICLE AND THE EQUATION OF MOTION OF SUPERSYMMETRIC PARTNERS
Authors: HARA OSAMU
Published: November 2004

The internal motion of the superparticle and the equation of motion of its supersymmetric partners are discussed based on the conservation laws resulting from the invariances possessed by the Lagrangian of the superparticle, one of which is the Lorentz invariance and the other is to be discussed here. It is shown that this leads to the existence of a new quantum number which is related to the spin but gives information independent of it.
EXACT RESULTS FOR THE SUPERSYMMETRIC G2 GAUGE THEORIES
Authors: PESANDO IGOR
Published: November 2004

We study the N=1 supersymmetric G2 gauge theories with Nf flavors of quarks in the fundamental vector representation. We find dynamically generated superpotentials, smooth quantum moduli space, quantum moduli space with additional mesons, nontrivial ir fixed points.
ENERGY AND ATOMIC MASS DEPENDENCE OF NUCLEAR STOPPING POWER IN RELATIVISTIC HEAVY-ION COLLISIONS IN INTERACTING GLUON MODEL
Authors: LIU Q.J. , CHAO W.Q. , WILK G.
Published: November 2004

We present a Monte-Carlo simulation of energy deposition process in relativistic heavyion collisions based on a new realization of the Interacting Gluon Model (IGM) for high energy N-N collisions. In particular we show results for proton spectra from collisions of E lab = 200 GeV/N 32 S beam incident on 32 S target and analyze the energy and mass dependence of nuclear stopping power predicted by our model. Theoretical predictions for proton rapidity distributions of both 208 Pb +208 Pb collisions at E lab =160 GeV/N CERN SPS and 197 Au +197 Au at [Formula: see text] BNL RHIC are given.
UNCONSTRAINED SUPERSPACE FORMALISM OF TOPOLOGICAL 2-D GRAVITY
Authors: TAHIRI M.
Published: November 2004

An unconstrained superconnection formalism is used to derive in a natural way the fields and their BRST transformations in topological 2-D gravity. Anti-BRST transformations of the fields are also obtained. We also show how the usual BRST exact quantum action is anti-BRST exact.
SOLUTION OF κ DEFORMED DIRAC EQUATION WITH ANOMALOUS MAGNETIC MOMENT INTERACTION
Authors: ROY P. , ROYCHOUDHURY R.
Published: November 2004

We construct the deformed Dirac equation with anomalous magnetic moment interaction and solve this equation for a charged particle in the presence of a constant magnetic field.
COSMIC STRINGS FROM N=2, D=5 SUPERGRAVITY
Authors: PIMENTEL LUIS O.
Published: November 2004

Exact solutions of N=2 supergravity in five dimensions are found in the metric with cylindrical symmetry, a particular case corresponds to the exterior of a cosmic string.
SCALING RELATION FOR THE $\Upsilon (4S)\to B\bar{B}$ AND $\psi (3770)\to
D\bar{D}$ DECAY CONSTANTS FROM PHENOMENOLOGICAL SUM RULES
Authors: KISELEV V.V.
Published: November 2004

The sum rules for exclusive production of heavy meson pairs in e+e− annihilation are used to evaluate the [Formula: see text] and [Formula: see text] decay widths. Infinitely heavy quark limit is discussed, and the scaling relation for the quarkonium-meson coupling constant is derived. The [Formula: see text] pair contribution into the leptonic constant fϒ(4S) is estimated.
N-POINT AMPLITUDES FOR d=2, c=1 DISCRETE STATES FROM STRING FIELD THEORY
Authors: AREF’EVA I. YA. , ZUBAREV A.P. , MEDVEDEV P.B.
Published: November 2004

Starting from string field theory for 2-D gravity coupled to c=1 matter we analyze N-point off-shell tree amplitudes of discrete states. The amplitudes exhibit the pole structure and we use the oscillator representation to extract the residues. The residues are generated by a simple effective action. We show that the effective action can be directly deduced from a string field action in a special transversal-like gauge.
INDICATIONS ON THE HIGGS-BOSON MASS FROM THE LEP DATA
Authors: CONSOLI M. , HIOKI Z.
Published: November 2004

We update our previous analysis on the Higgs mass mh and the QCD coupling αs(=αs(Mz)) by using the LEP data after the 1995 Winter Conferences. For mt= 180 GeV we find evidence for a rather large value of the Higgs mass in the range 500–1000 GeV, in agreement with the indications from the W mass.
CHIRAL ANOMALY IN d=4, N=1 SUPERGRAVITY
Authors: YAJIMA SATOSHI , HIGASIDA YOJI , TAIRA HIDEO
Published: November 2004

The chiral U (1) anomaly in d=4, N=1 supergravity is evaluated on the basis of the heat kernel method. We consider all gravitino interactions of the theory, i.e. not only the minimal coupling of gravitino and gravitational fields, but also four-gravitino interactions which are treated as two-gravitino interactions in the background field method. We show the explicit form of a new contribution from the four-gravitino interactions to the anomaly.
THE MASTER FIELD FOR LARGE-N MATRIX MODELS AND QUANTUM GROUPS
Authors: ACCARDI L. , AREF’EVA I.YA. , KOZYREV S.V. , VOLOVICH I.V.
Published: November 2004

In recent works by Singer, Douglas, Gopakumar and Gross an application of results of Voiculescu from noncommutative probability theory to constructions of the master field for large-N matrix field theories have been suggested. It turns out that this master field becomes the Boltzmann field in the free Fock space. In this note we consider interrelations between the master field and quantum semigroups. We define the master field algebra and observe that it is isomorphic to the algebra of functions on the quantum semigroup SU q(2) for q=0. The master field becomes a central element of the quantum group bialgebra. The quantum Haar measure on the SU q(2) for any q gives the Wigner semicircle distribution for the master field. Coherent states on SU q(2) become coherent states in the master field theory.
ENHANCEMENT OF THE MAGNETIC MOMENT OF THE ELECTRON DUE TO A TOPOLOGICAL DEFECT
Authors: MORAES FERNANDO
Published: November 2004

In the framework of the theory of defects/three-dimensional gravitation, a positive correction to the magnetic moment of the electron bound to a disclination in a dielectric solid is obtained.
MASSIVE SUPERSTRINGS ARE BLACK HOLES
Authors: FRAMPTON PAUL H. , KEPHART THOMAS W.
Published: November 2004

We argue that it is inconsistent to ignore backreaction for on-shell superstring states at the Planck mass and beyond, and that these quantum states become rotating black holes in the classical limit. Consequences are discussed.
INDUCED GAUGE FIELDS IN THE PATH-INTEGRAL
Authors: TANIMURA SHOGO , TSUTSUI IZUMI
Published: November 2004

The path-integral on a homogeneous space G/H is constructed, based on the guiding principle “first lift to G and then project to G/H”. It is then shown that this principle admits inequivalent quantizations inducing a gauge field (the canonical connection) on the homogeneous space, and thereby reproduces the result obtained earlier by algebraic approaches.
GAUGE-INVARIANT HAMILTONIAN FORMULATION OF LATTICE YANG-MILLS THEORY AND THE HEISENBERG DOUBLE
Authors: FROLOV S.A.
Published: November 2004

It is known that to get the usual Hamiltonian formulation of lattice Yang-Mills theory in the temporal gauge A0=0 one should place on each link a cotangent bundle of a Lie group. The cotangent bundle may be considered as a limiting case of a so-called Heisenberg double of a Lie group which is one of the basic objects in the theory of Lie-Poisson and quantum groups. It is shown in the paper that there is a generalization of the usual Hamiltonian formulation to the case of the Heisenberg double. The physical phase space of the (1+1)-dimensional γ-deformed Yang-Mills model is proved to be equivalent to the moduli space of flat connections on a two-dimensional torus.
MATRIX MODEL APPROACH TO d>2 NONCRITICAL SUPERSTRINGS
Authors: HASHIMOTO AKIKAZU , KLEBANOV IGOR R.
Published: November 2004

We apply light-cone quantization to a (1+1)-dimensional supersymmetric field theory of large-N matrices. We provide some preliminary numerical evidence that when the coupling constant is tuned to a critical value, this model describes a (2+1)-dimensional noncritical superstring.
THE SEARCH FOR NONSTANDARD HIGGS BOSONS WITH BIG YUKAWA COUPLING CONSTANTS AT FNAL AND LHC
Authors: KRASNIKOV N.V.
Published: November 2004

We discuss the phenomenology of many Higgs doublet model—the model where each Higgs doublet couples with its own quark and lepton with relatively big Yukawa coupling constants. Namely, we investigate the discovery potential of the Higgs bosons at LHC and find lower mass limits on nonstandard Higgs bosons from FNAL data. We find that it is possible to discover such Higgs bosons at LHC with the masses up to 5 TeV.
NEW MEASUREMENTS OF COSMIC RAY POSITRONS
Authors: TANG K.K.
Published: November 2004

Cosmic ray electrons consists of mostly negative electrons and a relatively smaller flux of positrons. A simple interpretation is that all the positrons, together with an approximately equal flux of negative electrons, are decay products of pions created in the interaction of cosmic ray protons with the interstellar medium, and the remaining negative electrons are produced in primary cosmic ray sources. However, the existing data on the positron fraction (e+/e++e−) does not support this simple picture. While the positron flux around a few GeV can be explained by the secondary production, there are apparently excesses of positrons both at lower and higher energies. This has stimulated many interpretation and conjectures of new astrophysical sources of positrons. Recently, there are new measurements from four different balloon experiments. They begin to show some discrepancy with the old data. A brief summary of the new results and their impact is given here.
CABIBBO ANGLE-ENHANCED AND DOUBLY SUPPRESSED D→Kπ WEAK DECAYS AND PCAC
Authors: SCADRON M.D.
Published: November 2004

The observed branching ratio of D°→K+π− to K−π+ is obtained using current algebra-PCAC consistency. The latter approach also sets the scale for the three Cabibbo angle-enhanced [Formula: see text] decays in a manner compatible with data.
THE QUANTUM GALILEI GROUP
Authors: GILLER S. , GONERA C. , KOSIŃSKI P. , MAŚLANKA P.
Published: November 2004

The quantum Galilei group Gκ is defined. The bicross-product structure of Gκ and the corresponding Lie algebra is revealed. The projective representations for two-dimensional quantum Galilei group are constructed.
THERMODYNAMICS OF BLACK HOLE IN (N+3) DIMENSIONS FROM EUCLIDEAN N-BRANE THEORY
Authors: ODA ICHIRO
Published: November 2004

In this letter we consider an N-brane description of an (N+3)-dimensional black hole horizon. First of all, we start by examining in more detail a previous work where a string theory is used in describing the dynamics of the event horizon of a four-dimensional black hole. This is an attempt to understand the black hole thermodynamics by an effective two-dimensional field theory of the event horizon of a black hole. Then we consider a particle model defined on one-dimensional Euclidean line in a three-dimensional black hole as a target spacetime metric. By solving the field equations we find a “worldline instanton” which connects the past event horizon with the future one. This solution gives us the exact value of the Hawking temperature and to leading order the Bekenstein-Hawking formula of black hole entropy. We also show that this formalism is extensible to an arbitrary spacetime dimension. Finally we make a comment of many recent works of one-loop quantum correction to the black hole entropy.
LOCAL SYMMETRIES STRUCTURE OF THE SUPERPARTICLE AND SUPERGRAVITY BACKGROUNDS
Authors: DERIGLAZOV A.A. , GALAJINSKY A.V.
Published: November 2004

The classical (1,0) superparticle in a curved superspace is considered. The minimal set of constraints to be imposed on the background for correct inclusion of interaction is found. The most general form of Siegel-type local fermionic symmetry is presented. Gauge algebra of the model is shown to be closed off-shell (by means of adding one trivial symmetry) and deformed as compared to the flat one. The form and algebraic structure of local symmetries of the theory are shown not to be deformed (in comparing with the flat case) in the (1,0) supergravity background only.
EXACT BETHE ANSATZ SOLUTION OF NON-ULTRALOCAL QUANTUM mKdV MODEL
Authors: KUNDU ANJAN
Published: November 2004

A lattice regularized Lax operator for the non-ultralocal modified Korteweg de Vries (mKdV) equation is proposed at the quantum level with the basic operators satisfying a q-deformed braided algebra. From the associated quantum R and Z-matrices the exact integrability of the model is proved through the braided quantum Yang-Baxter equation which is a suitably generalized equation for the non-ultralocal models. Using the algebraic Bethe ansatz the eigenvalue problem of the quantum mKdV model is exactly solved and its connection with the spin-1/2 XXZ chain is established, facilitating the investigation of the corresponding conformal properties.
AN EXTENDED N=1 FERMIONIC SUPERCURRENT AND ITS ASSOCIATED N=2 SUPERCONFORMAL ALGEBRA
Authors: PIERCE DAVID M.
Published: November 2004

An extended free fermionic construction of the internal N=1 worldsheet supercurrent for four-dimensional superstring theory is given. We show how it can describe theories with massless fermions, and we discuss the corresponding N=2 superconformal algebra. As an intermediate step, we show that an internal N=2 global superconformal invariance occurs in any superstring theory with massless fermions at tree level. To demonstrate this fact, we give the N=2 supercurrents for a model with N=1 spacetime supersymmetry and a model without spacetime supersymmetry.
PRECISION LOW ENERGY WEAK NEUTRAL CURRENT EXPERIMENTS
Authors: KUMAR K.S. , HUGHES E.W. , HOLMES R. , SOUDER P.A.
Published: November 2004

Precision measurements of weak neutral current amplitudes at [Formula: see text] are a sensitive probe of contact interactions arising from new high energy physics. Such measurements significantly enhance the analysis of precision data on the Z0 resonance, permitting tests of the running of the electroweak coupling constants. The behavior of the coupling constants as a function of Q2 can reveal the presence of many possible new physics scenarios, such as new gauge bosons, superparticles and substructure; some of these effects are difficult to observe on the Z0 pole. In order to probe energy scales up to 1 TeV, future low Q2 measurements must be precise enough to measure electroweak radiative corrections. Two experimental programs which aim to reach this sensitivity are deep inelastic neutrino nucleon scattering and atomic parity violation experiments. Another important technique is polarized electron scattering off unpolarized targets. We review the current status and future prospects of such measurements. We present an experimental design to measure the left-right parity violating asymmetry in polarized Møller scattering (e−e−→e−e−), which could constitute the most precise measurement of the weak mixing angle [Formula: see text] at [Formula: see text].
INSTABILITIES, POINT ATTRACTORS AND LIMIT CYCLES IN AN INFLATIONARY UNIVERSE
Authors: SALASNICH LUCA
Published: November 2004

We study the stability of a scalar inflaton field and analyze its point attractors in the phase space. We show that the value of the inflaton field in the vacuum is a bifurcation parameter and prove the possible existence of a limit cycle by using analytical and numerical arguments.
DIJETS PRODUCTION IN NONMINIMAL TECHNICOLOR AND LIMITS ON THE COLOR-OCTET TECHNIRHO MASS
Authors: ZERWEKH ALFONSO R.
Published: November 2004

Recently has been shown that the physical (mass eigenstate) color-octet technirho may not couple to two gluons. In this paper we study if this result can affect the presently accepted limits for the color-octet technirho mass obtained from the study of dijets production at the Tevatron. Our results show that no important changes are introduced on these limits.
ESTIMATING THE DIMENSIONAL CHARACTERISTICS OF TWO-DIMENSIONAL PATTERNS
Authors: ZHELEZNYAK A.L. , CHUA L.O.
Published: November 2004

Dynamical properties of two-dimensional patterns generated by spatially extended systems can be described via the characteristics of attractors in the matrix phase space of the associated translation (or translational-evolution) dynamical systems. Questions regarding the possibility of estimating the fractal dimensions of two-dimensional patterns from the fractal dimensions of one-dimensional observables scanning the patterns along a chosen path are investigated. The presented proofs state that the generalized dimensions of the scanning observables are lower bounds for estimating the corresponding generalized dimensions of two-dimensional patterns. Spatial field distributions defined as superposition of planar waves and different spatiotemporal patterns produced by cellular neural networks made of Chua’s circuits are studied numerically. The results of computer experiments confirm the theoretical predictions presented in this paper.
PENDULUM WITH POSITIVE AND NEGATIVE DRY FRICTION.: CONTINUUM OF HOMOCLINIC ORBITS
Authors: LEONOV G.A.
Published: November 2004

Pendulum-like systems with dry friction are considered. The existence of a continuum of homoclinic orbits with various homotopic properties on the cylinder is proven.
CHIRAL SELECTION OF ROTATING WAVES IN A REACTION-DIFFUSION SYSTEM: THE EFFECT OF A CIRCULARLY POLARIZED ELECTROMAGNETIC FIELD
Authors: ALMIRANTIS Y. , KAUFMAN M.
Published: November 2004

The interaction between a symmetry-breaking bifurcation and a weak external field represents a possible mechanism of pattern selection. Here, the coupling of a reaction-diffusion system operating under periodic boundary conditions, with a circularly polarized electromagnetic field is analyzed near a wave-producing bifurcation. The system is studied under resonant and quasiresonant conditions, the field frequency being equal or close to the system frequency or to one of its harmonics. A main result of this analysis is the existence of chiral pattern selection between the initially equiprobable clockwise and counterclockwise rotating waves, due to the splitting of the degenerate bifurcation point. A class of rotating solutions studied herein is found to form an isola.
LIMITING DYNAMICS FOR THE COMPLEX STANDARD FAMILY
Authors: FAGELLA NÚRIA
Published: November 2004

The complexification of the standard family of circle maps Fαβ(θ)=θ+α+β+β sin(θ) mod (2π) is given by Fαβ(ω)=ωeiαe(β/2)(ω−1/ω) and its lift fαβ(z)=z+a+β sin(z). We investigate the three-dimensional parameter space for Fαβ that results from considering a complex and β real. In particular, we study the two-dimensional cross-sections β=constant as β tends to zero. As the functions tend to the rigid rotation Fα,0, their dynamics tend to the dynamics of the family Gλ(z)=λzez where λ=e−iα. This new family exhibits behavior typical of the exponential family together with characteristic features of quadratic polynomials. For example, we show that the λ-plane contains infinitely many curves for which the Julia set of the corresponding maps is the whole plane. We also prove the existence of infinitely many sets of λ values homeomorphic to the Mandelbrot set.
CHAOS AND CHAOTIC TRANSIENTS IN A FORCED MODEL OF THE ECONOMIC LONG WAVE: THE ROLE OF HOMOCLINIC BIFURCATION TO INFINITY
Authors: STURIS JEPPE , BRØNS MORTEN
Published: November 2004

When an autonomous system of ordinary differential equations exhibits limit cycle behavior but is close in parameter space to a homoclinic bifurcation to infinity in which the limit cycle blows up to infinite amplitude and disappears, periodic forcing of the system may result in the appearance of both chaos and chaotic transients. In this paper, we use numerical techniques to map out Arnol’d tongues of a forced model of the economic long wave and illustrate how the system becomes chaotic and also exhibits chaotic transients for certain parameter combinations. Based on linearizations at infinity, we argue that infinity acts like a saddle with stable and unstable manifolds. By numerical computation, we show that chaotic transients occur when the manifolds intersect. Depending on parameters, two types of bifurcations have been identified: A chaotic attractor blows up to infinite size and disappears or the boundary of the basin of attraction of a periodic solution becomes fractal.
A NONLINEAR DYNAMICS INTERPRETATION OF ALGORITHMIC A/D CONVERSION
Authors: KENNEDY MICHAEL PETER
Published: November 2004

An algorithmic A/D converter may be viewed as a discrete-time dynamical system. From this perspective, an ideal one bit recycling binary converter corresponds to the Bernouilli Shift map. An implementation of the tent map (by means of a folding circuit or otherwise) yields an algorithmic converter with Gray code output.
FINDING PARAMETERS FOR CHUA’S OSCILLATOR WHICH IS TOPOLOGICALLY CONJUGATE TO SYSTEMS WITH A SCALAR NONLINEARITY
Authors: WU CHAI WAH , CHUA LEON O.
Published: November 2004

Chua’s oscillator is topologically conjugate to a large class of vector fields with a scalar non-linearity. In this letter, we give an algorithm which, given a vector field in this class, finds the parameters for Chua’s oscillator for which Chua’s oscillator is topologically conjugate to it. We illustrate this by transforming Sparrow’s system and the chaotic Colpitts oscillator into equivalent Chua’s oscillators.
STABILITY OF SYNCHRONIZATION IN NETWORKS OF DIGITAL PHASE-LOCKED LOOPS
Authors: GOLDSZTEIN GUILLERMO , STROGATZ STEVEN H.
Published: November 2004

We analyze the linear stability of the synchronized state in networks of N identical digital phase-locked loops. These are pulse-coupled oscillator arrays in which the frequency (rather than the phase) of each oscillator is updated discontinuously whenever that oscillator reaches a specific phase in its cycle. Three different coupling configurations are studied: one-way rings, two-way rings, and globally coupled arrays. In each case we obtain explicit formulas for the transient time to lock, the critical gain at which the synchronized state loses stability, and the period of the bifurcating solution at the onset of instability. Our results explain the numerical observations of de Sousa Vieira, Lichtenberg, and Lieberman.
FRACTAL AGGREGATION OF BASIN ISLANDS IN TWO-DIMENSIONAL QUADRATIC NONINVERTIBLE MAPS
Authors: MIRA C. , RAUZY C.
Published: November 2004

Properties of basins of noninvertible maps of the plane are studied by using the method of critical curves. The paper considers the simplest class of quadratic maps, that having a phase plane made up of two regions, one with two first rank preimages, the other with no preimage, in situations different from those described in a previous publication. More specifically, the considered quadratic maps give rise to a basin made up of infinitely many nonconnected regions, a parameter variation leading to an aggregation of these regions, which occur in a fractal way. The nonconnected regions, different from that containing an attracting set, are called "islands".
BISTABILITY, BIFURCATION AND CHAOS IN A LASER SYSTEM
Authors: O'CAIRBRE F. , O'FARRELL A. G. , O'REILLY A.
Published: November 2004

In this paper we study a one-dimensional dynamical system that provides a model for the evolution of a Fabry–Perot cavity in Laser Physics. We determine the parameter ranges for bistability and chaos in the system. We also examine the bifurcations of the system and the occurrence of various types of cycles.
CHAOTIC PHENOMENA IN AN ORDER 1 DPCM TRANSMISSION SYSTEM
Authors: UHL C. , FOURNIER-PRUNARET D.
Published: November 2004

The existence of chaotic phenomena in DPCM transmission systems of order 1 is studied. The coupling at the encoder between the nonlinear quantization and the prediction makes the encoder recursive even if the prediction is transversal; The encoder has a feedback loop which is a recursive linear filter. For an order 1 transversal predictor, the bifurcation structure of the encoder state equations is determined. It is proven that the encoder output signal may be chaotic even if the stability condition of the linear filter is satisfied. Parameters giving rise to chaotic phenomena can be determined in order to avoid dysfunctioning of the system.
SELF-SIMILARITY MAPS FOR THE SET OF UNIMODAL CYCLES
Authors: BERNHARDT CHRIS
Published: November 2004

Self-similarity maps are defined for the set of unimodal cycles ordered by the forcing relation. Two examples, with dynamical interpretations, are given.
ZERO ENTROPY PERMUTATIONS
Authors: BLOCK LOUIS , BLOKH ALEXANDER M. , COVEN ETHAN M.
Published: November 2004

The entropy of a permutation is the (topological) entropy of the "connect-the-dots" map determined by it. We give matrix- and graph-theoretic, geometric, and dynamical characterizations of zero entropy permutations, as well as a procedure for constructing all of them. We also include some information about the number of zero entropy permutations.
COMBINATORICS OF THE KNEADING MAP
Authors: BRUIN H.
Published: November 2004

The kneading map and the Hofbauer tower are tools, developed by F. Hofbauer and G. Keller, to study unimodal maps and the kneading theory. In this paper we survey the geometric properties of these tools. Results concerning the topological structure of the critical omega-limit set are obtained.
DESIGN OF ONE-DIMENSIONAL CHAOTIC MAPS WITH PRESCRIBED STATISTICAL PROPERTIES
Authors: BARANOVSKY A. , DAEMS D.
Published: November 2004

The statistical properties of a wide class of 1D piecewise linear Markov maps are compiled. The method used enables one to address analytically the inverse problem of designing a map with a prescribed correlation function. This class of piecewise linear maps is then used as a system of reference to analyze non-Markov piecewise linear maps and to design maps with given invariant measure and correlation function.
THE SPECTRAL STATISTICS OF TRIANGULAR QUANTUM BILLIARDS
Authors: BELLOMO PAOLO
Published: November 2004

We study the spectral statistics of three triangular quantum billiards. We show that for an ergodic billiard the nearest neighbor spacings distribution in the low energy regime is strongly influenced by a neighboring integrable domain (equilateral triangle). With increasing energy we observe a transition towards a more chaotic-like pattern. We also show that for all three triangles the properties of the spectral distributions depend heavily on the energy range considered. This is specially true for the spectral rigidity, because of its essentially local character. The features of the distributions do not depend strongly on the genus of classical billiards.
DYNAMICS OF TWO COUPLED CHUA'S CIRCUITS
Authors: ANISHCHENKO V. C. , VADIVASOVA T. E. , ASTAKHOV V. V. , SOSNOVTSEVA O. V. , WU C. W. , CHUA L. O.
Published: November 2004

Two resistively coupled Chua's circuits are studied in this paper. We consider the case when the two circuits are identical, and the case when there is a detuning between the basic frequencies of the two circuits. In the first case, the multistability (i.e. the coexistence of attractors) evolution scenario is studied. In the second case, we study the influence of detuning on the multistability, and on the mutual synchronization in the chaotic regimes. We present bifurcation diagrams of the main synchronization regions. We also compare the dynamics of coupled Chua's circuits with the dynamics of other coupled systems.
TOWARD EXPERIMENTAL IMPLEMENTATIONS OF MIGRATION CONTROLS
Authors: JACKSON E. ATLEE , GROSU I.
Published: November 2004

Jackson and Grosu developed a method for controlling complex dynamic systems that employs an open-plus-closed-loop control components (the OPCL method), and proved that it is capable of entraining the dynamics of standard dynamic systems to arbitrary goal dynamics, g(t) ∈ Rn [Jackson & Grosu, 1995]. Rather than use this control for entrainment, one of us has shown [Jackson, 1995] how the OPCL can be easily employed to transfer the dynamics of a multiple-attractor system from one attractor to another ("migration controls" [Jackson, 1990]). For this purpose, a Chua-circuit model with five distinct attractors was used. In the present study we will show how to experimentally implement the OPCL migration control on such a circuit, by using prerecorded signals, which makes it possible to restrict the control action to only one dynamic component.
FRACTALS AND VIBRATIONS: CAN YOU HEAR THE SHAPE OF A FRACTAL DRUM?
Authors: LAPIDUS MICHEL L.
Published: November 2004

We study various aspects of the question “Can one hear the shape of a fractal drum?”, both for “drums with fractal boundary” (or “surface fractals”) and for “drums with fractal membrane” (or “mass fractals”).
FRACTAL APPROACHES IN SIGNAL PROCESSING
Authors: LÉVY-VÉHEL JACQUES
Published: November 2004

Some recent advances in the application of fractal tools for studying complex signals are presented. The first part of the paper is devoted to a brief description of the theoretical methods used. These essentially consist of generalizations of previous techniques that allow us to efficiently handle real signals. We present some results dealing with the multifractal analysis of sequences of Choquet capacities, and the possibility of constructing such capacities with prescribed spectrum. Related results concerning the pointwise irregularity of a continuous function at each point are given in the frame of iterated functions systems. Finally, some results on a particular stochastic process are sketched: the multifractional Brownian motion, which is a generalization of the classical fractional Brownian motion, where the parameter H is replaced by a function. The second part consists of the description of selected applications of current interest, in the fields of image analysis, speech synthesis and road traffic modeling. In each case we try to show how a fractal approach provides new means to solve specific problems in signal processing, sometimes with greater success than classical methods.
FIXED SCALE TRANSFORMATION APPROACH FOR BORN MODEL OF FRACTURES
Authors: CALDARELLI GUIDO , VESPIGNANI ALESSANDRO
Published: November 2004

We use the Fixed Scale Transformation theoretical approach to study the problem of fractal growth in fractures generated by using the Born Model. In this case the application of the method is more complex because of the vectorial nature of the model considered. In particular, one needs a careful choice of the lattice path integral for the fracture evolution and the identification of the appropriate way to take effectively into account screening effects. The good agreement of our results with computer simulations shows the validity and flexibility of the FST method in the study of fractal patterns evolution.
GROWTH OF Ge ON In-ADSORBED Si(111) SURFACES STUDIED BY UHV-REM
Authors: MINODA H. , TANISHIRO Y. , YAMAMOTO N. , YAGI K.
Published: November 2004

Growth of Ge on In-adsorbed Si (111)[Formula: see text] and 4×1 surfaces was studied by REM-RHEED. Indium atoms were segregated to the topmost surface during Ge deposition. The formation of the 1×1 structure, which is one of the In-adsorbed structures on the Ge (111) surface, was observed on both the [Formula: see text] structure and the 4×1 surface structures. Suppression of two- and three-dimensional island nucleation of Ge by In predeposition was noticed below 430°C on both surface structures. The critical thickness at which the layer growth mode changed to the island growth mode on the 4×1 surface structure was larger than that on the [Formula: see text] surface structure. Apparent surface diffusion lengths of Ge changed after 2 ML deposition of Ge on the [Formula: see text] surface structure.
SURFACE STUDIES BY CORE-EXCITATION REFLECTION ELECTRON ENERGY LOSS SPECTROSCOPY
Authors: HITCHCOCK A.P. , TYLISZCZAK T.
Published: November 2004

Inelastic electron scattering in a reflection geometry is a useful alternative to synchrotron radiation X-ray absorption spectroscopy for inner-shell excitation studies of surfaces. This article reviews the current capabilities of reflection electron energy loss spectroscopy for core-excitation studies of the electronic and geometric structure of surfaces. Issues discussed include: momentum transfer dependence, comparison to X-ray techniques, orientational sensitivity, spatial and energy resolution, and technological applications. Examples of applications to clean surfaces, atomic and molecular adsorbates, and thin films are given.
LOW-DIMENSIONAL ELECTRONIC STATES AT METAL SURFACES: QUANTUM WELLS AND QUANTUM WIRES
Authors: HIMPSEL F.J.
Published: November 2004

Several possibilities of “engineering” low-dimensional solids on the atomic scale are discussed. The electronic and magnetic structure of such materials is explored for two classes, i.e., multilayers and “wires” attached to step edges. Magnetic multilayers represent a particularly promising case, since quantum effects have macroscopic consequences. Quantization perpendicular to the layers is connected with oscillatory magnetic coupling, which in turn is important for obtaining “giant” magnetoresistance. This effect is being applied towards the fabrication of magnetoresistive reading heads for magnetically stored data. Extensions towards lateral superlattices and quantum wires are explored, where a stepped surface acts as a template. It is found that electrons can be trapped at step edges, and level shifts of the order 0.5 eV are observed for atoms adsorbed at step edges.
A PHOTOEMISSION STUDY OF THE ELECTRONIC STRUCTURE INDUCED BY POTASSIUM ADSORPTION ON TiO2(110)
Authors: HEISE RAINER , COURTHS RALF
Published: November 2004

Electronic structure effects induced by potassium adsorption up to one monolayer (ML) on a nearly stoichiometric TiO 2(110) surface has been studied by means of angle-resolved photoemission spectroscopy (ARUPS and ARXPS) from valence states and core levels. In agreement with the observations on K/TiO 2(100) [P.J. Hardman et al., Surf. Sci.269/270, 677 (1992)], potassium adsorption at room temperature leads—due to K-to-substrate charge transfer—to the reduction of surface Ti ions (to nominally Ti 3+ ions), evidenced by lowered Ti 2p core-level binding energy (ΔBE=–1.6 eV ) and occupation of Ti 3d-like band-gap states centered at 0.9 eV BE. The gap-state intensity exhibits a pronounced maximum at 0.37 ML coverage, where the work function has a weak minimum. This behavior is in agreement with a ionic-to-neutral transition of the K-substrate bonding with increasing K coverage, as suggested recently [Souda et al., Surf. Sci.285, 265 (1993)]. Annealing of a surface precovered with 0.27 ML potassium up to 1000 K results in metallization of the surface, evidenced by (i) the occupation of a second gap-state centered at 0.4 BE and with a considerable state-density at the Fermi energy, and (ii) Ti 2p core-levels lowered by 3.2 eV in BE (nominally “ Ti 2+” ions). This dramatic reduction of the surface is healed out with complete desorption of potassium. A discussion in terms of desorption of KO x species and oxygen diffusion from the bulk to the surface is given.
MODIFICATION OF THE ELECTRICAL RESISTANCE OF THIN COBALT FILMS UPON THE ADSORPTION OF CARBON MONOXIDE
Authors: CABRERA A.L. , GARRIDO-MOLINA W.H. , VOLKMANN U.G.
Published: November 2004

Thin films of pure Co with thicknesses ranging between 10 and 50 nm were produced in UHV conditions. The films were deposited onto mica substrates with dimensions of 1 cm ×1 cm ×0.1 cm . Thin gold wires were attached to the ends of the films in order to monitor their electrical resistivity. The films were introduced into a UHV chamber which consists of a quadrupole mass spectrometer and an Arsputtering gun for cleaning. The films were exposed to 10−6 torr of high-purity CO and the resistivity of the films was monitored during exposure. The resistivity changed in a “sawtooth” fashion similar to the changes observed by Pick in the Nb/H 2 system. The aim of these studies is to correlate changes in resistivity of the film with well-characterized adsorption states of CO on the Co surface. Carbon monoxide desorption from the cobalt films was studied (using a mass spectrometric method in an ultrahigh vacuum system) and two carbon monoxide desorption peaks were observed identical to prior work using Co foils. These two states correspond to molecular CO and presumably dissociated CO. Changes in resistivity of the thin Co films appear to be related only to the molecular CO adsorbed on the Co surface.
XPS STUDIES OF THE STABILITY OF A MIXED ZIRCONIUM OXIDE AND SULPHIDE THIN FILM
Authors: WONG P.C. , LI Y.S. , ZHOU M.Y. , MITCHELL K.A.R.
Published: November 2004

A 25 Å film formed by depositing zirconium (~2 Å min –1) onto gold foil in the presence of H 2 S (~5×10−8 mbar ) and H 2 O (~1×10−9 mbar ) has been studied by XPS. This film has an outer region composed of a mixed zirconium oxide/sulphide, while below there is metallic zirconium plus Zr/Au alloy in contact with gold. This film appears stable on heating to 400°C under UHV insofar as the sulphide part does not change, although the oxide part increases apparently as a result of some reaction of metallic zirconium with ambient water. By contrast, when this preheated film at room temperature was treated with a hydrogen plasma, the sulphide component was completely removed and the whole film was converted to the ZrO 2-like form with enhanced formation of OH groups. The hydrogen plasma treatment is therefore capable of desulphurizing the mixed zirconium oxide/sulphide film.