bluuebunny/crossref_metadata_2025 huggingface dataset:
SELF-DUAL SUPERGRAVITY AND SUPERSYMMETRIC YANG-MILLS THEORY COUPLED TO GREEN-SCHWARZ SUPERSTRING
Authors: NISHINO HITOSHI
Published: November 2004

We present the canonical set of superspace constraints for self-dual supergravity, a “self-dual” tensor multiplet and a self-dual Yang-Mills multiplet with N=1 supersymmetry in the space-time with signature (+,+, −, −). For this set of constraints, the consistency of the self-duality conditions on these multiplets with supersymmetry is manifest. The energy-momentum tensors of all the self-dual “matter” multiplets vanish, to be consistent with the self-duality of the Riemann tensor. In particular, the special significance of the “self-dual” tensor multiplet is noted. This result fills the gap left over in our previous series of papers, with respect to the consistent couplings among the self-dual matter multiplets. We also couple these nontrivial backgrounds to a Green-Schwarz superstring σ model, under the requirement of invariance under fermionic (kappa) symmetry. The finiteness of the self-dual supergravity is discussed, based on its “off-shell” structure. A set of exact solutions for the “self-dual” tensor and self-dual Yang-Mills multiplets for the gauge group SL(2) on a self-dual gravitational instanton background is given, and its consistency with the Green-Schwarz string σ model is demonstrated.
ARE GLUONS MASSIVE?
Authors: FIELD J.H.
Published: November 2004

The mass of the gluon is determined using asymptotic perturbative QCD in the [Formula: see text] renormalization scheme. The experimental determination of the couplant ās(2), which occurs in the perturbation expansions for [Formula: see text] and [Formula: see text] together with an estimate of the on-shell couplant, αs=0.096±0.016 [or αs(0)=0.30±0.05], yields the results [Formula: see text] if typical current (constituent) masses are assigned to the quarks.
STRESS-ENERGY TENSOR AND ULTRAVIOLET BEHAVIOR IN MASSIVE INTEGRABLE QUANTUM FIELD THEORIES
Authors: MUSSARDO G. , SIMONETTI P.
Published: November 2004

The short distance behavior of massive integrable quantum field theories is analyzed in terms of the form factor approach. We show that the on-shell dynamics is compatible with different definitions of the stress-energy tensor Tµν(x) of the theory. In terms of form factors, this is equivalent to having a possible nonzero matrix element F1 of the trace of Tµν on a one-particle state. Each choice of F1 induces a different scaling behavior of the massive theory in the ultraviolet limit.
GAUGING OF CHERN-SIMONS p-BRANES
Authors: ZAIKOV RAIKO P.
Published: November 2004

The Chern-Simons membranes and in general the Chern-Simons p-branes moving in D-dimensional target space admit an infinite set of secondary constraints. With respect to the Poisson bracket these constraints form a closed algebra which contains the classical W1+∞ algebra in p dimensions as a subalgebra. A corresponding gauged theory in the phase space is constructed in a Hamiltonian gauge as an analog of the ordinary W gravity.
THE TACHYON FIELD BELOW THE MASS BARRIER
Authors: BARCI D.G. , BOLLINI C.G. , ROCCA M.C.
Published: November 2004

We consider a tachyon field whose Fourier components correspond to spatial momenta with modulus smaller than the mass parameter. The plane wave solutions have then a time evolution which is a real exponential. The field is quantized and the solution of the eigenvalue problem for the Hamiltonian leads to the evaluation of the vacuum expectation value of products of field operators. The propagator turns out to be half-advanced and half-retarded. This completes the proof4 that the total propagator is the Wheeler Green function.4,7
A DERIVATION OF THE SCHWARZSCHILD EQUATIONS BY THE USE OF NEWTONIAN MECHANICS
Authors: SAVICKAS D.
Published: November 2004

An exact derivation of both the Schwarzschild metric of general relativity and its equations of motion is made by the use of Newtonian mechanics. Although the form of Newtonian mechanics itself is not modified, the concepts of length and time on which it is based are modified in a manner that allows Newton’s laws to be expressed in a non-Euclidean space-time geometry. The lengths used in the laws are defined in terms of local-scale-measured distances, rather than the usual coordinate distances. Particle velocities are then defined in terms of these differential scale lengths. The Newtonian law of gravitation is also defined in terms of the gradient of the usual Newtonian potential with respect to these same scale lengths. It is shown that non-Euclidean geometry is imposed by the requirement that a photon in a gravitational field should maintain a constant total energy that is expressed in terms of its frequency, while also having a potential energy that is independent of the geometry of space. These conditions and modifications make it possible to derive equations of motion which are Newtonian, but which can also be reduced to forms that are identical to the Schwarzschild equations of motion for an orbiting particle or a gravitationally deflected photon.
QUANTUM NON-ABELIAN TODA FIELD THEORIES
Authors: JACK I. , JONES D.R.T. , PANVEL J.
Published: November 2004

We derive an explicit, exactly conformally invariant form for the action for the non-Abelian Toda field theory. We demonstrate that the conformal invariance conditions, expressed in terms of the β functions of the theory, are satisfied to all orders, and we use our results to obtain a value for the central charge agreeing with previous calculations.
RESONANT AND NONRESONANT PIECES OF THE $D\to \bar K\pi$ SEMILEPTONIC TRANSITION AMPLITUDE
Authors: SCHECHTER J. , SUBBARAMAN A. , SURYA S.
Published: November 2004

We compare the resonant and nonresonant contributions in various regions of phase space for the [Formula: see text] semileptonic transition amplitude, computed in a chiral model which incorporates the heavy quark symmetry. Remarks on the significance for experiment and for chiral perturbation theory are made.
THE STATISTICS TRANSMUTING CHERN–SIMONS FIELD AND THE BRAID GROUP ON RIEMANN SURFACES OF GENUS g > 0
Authors: FAYYAZUDDIN ANSAR
Published: November 2004

We study bosons interacting with an Abelian Chern–Simons field on Riemann surfaces of genus g > 0. It is shown that a singular gauge transformation brings the Hamiltonian to free form. The transformed wave functions furnish a multicomponent representation of the braid group for spinning anyons studied by Imbo and March-Russell and Einarsson, among others. The construction constitutes a proof of the equivalence of bosons coupled to a Chern–Simons field and anyons and generalizes the well-known equivalence of the two pictures on the plane.
AREA-PRESERVING DIFFEOMORPHISMS, W∞ AND ${\mathcal U}_q [{\rm sl}(2)]$ IN CHERN–SIMONS THEORY AND THE QUANTUM HALL SYSTEM
Authors: KOGAN IAN I.
Published: November 2004

We discuss a quantum [Formula: see text] symmetry in the Landau problem, which naturally arises due to the relation between [Formula: see text] and the group of magnetic translations. The latter is connected with W∞ and area-preserving (symplectic) diffeomorphisms which are the canonical transformations in the two-dimensional phase space. We shall discuss the hidden quantum symmetry in a 2 + 1 gauge theory with the Chern–Simons term and in a quantum Hall system, which are both connected with the Landau problem.
ABELIAN ANOMALIES IN NONLOCAL REGULARIZATION
Authors: CLAYTON M.A. , DEMOPOULOS L. , MOFFAT J.W.
Published: November 2004

The nonlocal regularization of QED is shown to possess an axial anomaly of the same form as other regularization schemes. The Noether current is explicitly constructed and the symmetries are shown to be violated, whereas the identities constructed when one properly considers the contribution from the path integral measure are respected. We also discuss the merits and new features of the regularization scheme, as well as the barrier to quantizing the fully gauged chiral-invariant theory.
A NEW SET OF EXACT FORM FACTORS
Authors: SMIRNOV FEODOR A.
Published: November 2004

We present form factors for a wide range of integrable models which include marginal perturbations of the SU(2) WZNZ model for arbitrary central charge and the principal chiral field model. The interesting structure of these form factors is discussed.
ALTERNATIVE CANONICAL FORMALISM FOR THE WESS-ZUMINO-WITTEN MODEL
Authors: RAJEEV S.G. , SPARANO G. , VITALE P.
Published: November 2004

We study a canonical quantization of the Wess-Zumino-Witten (WZW) model which depends on two integer parameters rather than one. The usual theory can be obtained as a contraction, in which our two parameters go to infinity keeping the difference fixed. The quantum theory is equivalent to a generalized Thirring model, with left- and right-handed fermions transforming under different representations of the symmetry group. We also note that the classical WZW model with a compact target space has a canonical formalism in which the current algebra is an affine Lie algebra of the noncompact type. In addition, there are some nonunitary quantizations of the WZW model in which there is invariance only under half the conformal algebra (one copy of the Virasoro algebra).
GAUGED SU(2)L×SU(2)R/SU(2)L+Rσ MODEL IN THE FRAMEWORK OF NONCOMMUTATIVE GEOMETRY
Authors: HWANG DAE SUNG , LEE TAEHOON
Published: November 2004

We study the gauged SU(2) L× SU(2) Rσ model in the SU(2|2) superalgebra formalism. The superconnection is taken to have one-form vector fields as its even part and zero-form scalar fields as its odd part. Incorporating the matrix derivative of noncommutative geometry proposed by Connes and Coquereaux et al., we naturally obtain the spontaneously symmetry broken SU(2) L× SU(2) Rσ model. The masses of the axial vector gauge fields and the Higgs fields are obtained.
A TEST OF OPTIMIZED PERTURBATIVE QCD TO ${\mathcal O}(\alpha _s^2)$ AND ${\mathcal O}(\alpha_s^3)$ FROM Z0 AND τ DECAYS, AND A METHOD TO DEAL WITH THE RENORMALIZATION SCALE AMBIGUITY
Authors: SANGHERA SUKHPAL
Published: November 2004

A QCD analysis of the published LEP data on 11 observables measured in the Z0 and τ decays is performed in order to probe the renormalization scale optimization of perturbative QCD to [Formula: see text] and [Formula: see text]. The explicit dependence of the fundamental QCD parameter [Formula: see text] on the renormalization scale μ2 is extracted from the data. The theoretical predictions for the optimized scale are calculated using various QCD-inspired procedures, and are compared to the experimental results. An experimental procedure is presented to deal with the renormalization scale ambiguity in the determination of αs. Applying this procedure to 11 observables, we obtain αs(Mz0)=0.114±0.004 as our final result.
c=1 STRING AS A TOPOLOGICAL MODEL
Authors: ISHIKAWA HIROSHI , KATO MITSUHIRO
Published: November 2004

The discrete states in the c=1 string are shown to be the physical states of a certain topological sigma model. We define a set of new fields directly from c=1 variables, in terms of which the BRST charge and energy-momentum tensor are rewritten as those of the topological sigma model. Remarkably, ground ring generator x turns out to be a coordinate of the sigma model. All of the discrete states realize a graded ring which contains the ground ring as a subset.
A PARTICULAR CLASS OF GUTS WITH VANISHING ONE-LOOP BETA FUNCTIONS
Authors: LUCHA WOLFGANG , SCHÖBERL FRANZ F.
Published: November 2004

By explicit solution of the one-loop finiteness conditions for gauge and quartic scalar-boson self-interaction coupling constants, a particular class of grand unified theories with vanishing Yukawa couplings as well as vanishing one-loop renormalization-group beta functions is constructed.
ALMOST INTEGRABLE MAPPINGS
Authors: BOUKRAA S. , MAILLARD J.-M. , ROLLET G.
Published: November 2004

We analyze birational transformations obtained from very simple algebraic calculations, namely taking the inverse of q × q matrices and permuting some of the entries of these matrices. We concentrate on 4 × 4 matrices and elementary transpositions of two entries. This analysis brings out six classes of birational transformations. Three classes correspond to integrable mappings, their iteration yielding elliptic curves. Generically, the iterations corresponding to the three other classes are included in higher dimensional non-trivial algebraic varieties. Nevertheless some orbits of the parameter space lie on (transcendental) curves. These transformations act on fifteen (or q2 − 1) variables, however one can associate to them remarkably simple non-linear recurrences bearing on a single variable. The study of these last recurrences gives a complementary understanding of these amazingly regular non-integrable mappings, which could provide interesting tools to analyze weak chaos.
FIELD THEORY APPROACH TO CRITICAL QUANTUM IMPURITY PROBLEMS AND APPLICATIONS TO THE MULTI-CHANNEL KONDO EFFECT
Authors: LUDWIG Andreas W. W.
Published: November 2004

A new, general approach to finding exact solutions of Quantum Impurity Problems is reviewed, in which a local quantum mechanical degree of freedom is coupled to an extended variable, having gapless excitations. The principle ideas, using Conformal Field Theory techniques, are demonstrated in the example of the Multi-Channel Kondo effect, which exhibits unusual non-Fermi-liquid behavior at low temperatures and which appears to be relevant for Heavy Fermion Materials. In particular, static and dynamic Green's functions as well as transport and pairing properties are calculated exactly at low temperatures. Quantum Impurity Problems provide realizations of non-trivial, fully interacting Conformal Field Theories.
CRITICAL EXPONENTS IN THE ONE-DIMENSIONAL HUBBARD MODEL
Authors: Frahm Holger , Korepin V. E.
Published: November 2004

Exact Bethe Ansatz results on the spectrum of large but finite Hubbard chains in conjunction with methods from conformal quantum field theory can be used to obtain exact results for the asymptotic behaviour of correlation functions. We review this method and discuss some interesting consequences of the results.
THE CN TODA CHAIN
Authors: Pasquier V.
Published: November 2004

We obtain the exact equation for the spectrum of the CN Toda chain and for a spin chain which gives the Toda chain back in the infinite spin limit. The method we use is a variant of the Bethe Ansatz technique discovered by Sklyanin based on M. Gutzwiller's solution of the AN case.
HOPPING AND DISSIPATIVE TUNNELING OF ORIENTATIONAL DEFECTS IN ICE
Authors: Careri Giorgio , Bruni Fabio , Consolini Giuseppe
Published: November 2004

We have measured the dielectric relaxation time of orientational defects for H2O and D2O polycrystalline ice samples, in the temperature range 200–270 K, and over the frequency range 0.3–1000 kHz. Results are in good agreement with previous studies, and at T<240 K departures from the familiar Arrhenius law have been observed. We show that these deviations from classical rate theory can be well described within the framework of dissipative quantum tunneling (DQT) theory, assuming impurity-generated Bjerrum defects responsible for the observed dielectric relaxation process over the entire temperature range investigated. The temperature regions where quantum tunneling, crossover to thermal hopping, and quantum corrections to classical laws, respectively prevail are here reviewed. Particularly significant is the perfect agreement, near the crossover temperature Tc, of all our different samples with a universal scaling law, as predicted by DQT theory. The crossover temperature Tc, where quantum tunneling and thermal hopping merge, has been found close to 240 K and to 220 K for H2O and D2O ice respectively, thus showing the higher relevance of quantum effects in H2O ice. It is shown that the dielectric relaxation time of orientational defects for both H2O and D2O ice samples never attains a fully classical behaviour, even at their melting temperature.
Coulomb Gap in the Tunneling Density of States of Two-Dimensional Electron Liquid in a Strong Magnetic Field
Authors: Efros A.L. , Pikus F.G.
Published: November 2004

A model of a classical electron liquid without external disorder is applied to two-dimensional electrons in a strong magnetic field. Computer modeling gives a quantitative explanation for the recently observed gap in the tunneling current of a double quantum well structure. We find that both the Coulomb gap in the single-well density of states and the correlation of electron motion in the two wells are responsible for the tunneling gap. We show that the classical liquid model provides an accurate description of the low temperature compressibility obtained from magnetocapacitance experiment.
GROUP THEORY CLASSIFICATION SCHEMES OF THE N-ELECTRON QUANTUM DOT
Authors: HAASE R.W. , JOHNSON N.F.
Published: November 2004

We develop a general framework for discussing collective behavior in confined many-electron systems. Our specific goal is the application to N-electron quantum dots, which are mesoscopic semiconductor systems of great current interest as possible ultra-small electronic devices. In view of its broad applicability, we are able to cast the discussion of the many-electron problem in general terms. We consider the general N-interacting particle system in d dimensions and study its bilinear dynamical symmetry group which is the noncompact symplectic group Sp(2Nd, R). Giving their explicit dependence on N and d, we focus on the classification of many-particle bound states which requires knowledge of the unitary discrete series representation theory of Sp(2Nd, R) and the corresponding character reductions. We also discuss matrix elements of the generators, the implementation of the Pauli principle, and a procedure to derive total angular momentum quantum numbers associated with a given total spin.
REACTIVE ION ETCHING OF III–V SEMICONDUCTORS
Authors: PEARTON S.J.
Published: November 2004

Anisotropic dry etching by a number of different techniques is widely employed in III–V compound semiconductor technology for pattern transfer, device isolation, mesa formation, grating fabrication and via hole etching. In this paper we review the different dry etching techniques, the plasma chemistries employed for III–V materials and electrical and optical changes to the near-surface of the etched sample. We give examples of the use of dry etching in fabrication of heterojunction bipolar transistors, field effect transistors and various types of semiconductor lasers. Particular attention is paid to the characteristics of Electron Cyclotron Resonance discharges operating at high ion densities (≥5×1011 cm −3) and low pressure (~1 mTorr) with low ion energies (≤15 eV ) which are ideally suited for dry etching of III–V semiconductors.
THE MICROSCOPIC THEORY OF SURFACE PROPERTIES OF ANHARMONIC CRYSTALS III: SINGULAR SURFACES OF SIMPLE CUBIC CRYSTALS
Authors: ZUBOV V.I. , MAMONTOV I.V. , BAZIRUWIHA J.D.
Published: November 2004

A theoretical study of the singular surfaces of simple cubic crystals has been fulfilled using the correlative unsymmetrized self-consistent field method (CUSF) for anharmonic crystals developed in preceding works. The lattice relaxation, amplitudes of the anharmonic vibrations of atoms and their anisotropy have been calculated. The excess thermodynamic functions have been found: the surface energy and Helmholtz free energy, surface stress and tension, surface entropy and specific heat. The results are compared with those obtained earlier for other cubic lattices and for the two-dimensional model with square lattice.
RANDOM MIXED SPINS ISING MODEL ON THE HONEYCOMB LATTICE
Authors: GONÇALVES J.R. , GONÇALVES L.L.
Published: November 2004

The Ising model on the honeycomb lattice with spins of magnitudes 1/2 and s with random exchange constant and random uniaxial anisotropy is considered. The two cases are studied separately, and in both cases binary annealed distributions of the random parameters are considered. An exact solution is obtained by mapping the model onto the uniform spin 1/2 Ising model on the triangular lattice, and the transition temperature is determined as a function of the parameters for arbitrary s. Explicit results are presented for s=1 and s=3/2, and it is shown that some critical parameters, surprisingly, are not universal.
DETERMINANTAL IDENTITIES ON INTEGRABLE MAPPINGS
Authors: BOUKRAA S. , MAILLARD J-M. , ROLLET G.
Published: November 2004

We describe birational representations of discrete groups generated by involutions, having their origin in the theory of exactly solvable vertex-models in lattice statistical mechanics. These involutions correspond respectively to two kinds of transformations on q×q matrices: the inversion of the q×q matrix and an (involutive) permutation of the entries of the matrix. In a case where the permutation is a particular elementary transposition of two entries, it is shown that the iteration of this group of birational transformations yield algebraic elliptic curves in the parameter space associated with the (homogeneous) entries of the matrix. It is also shown that the successive iterated matrices do have remarkable factorization properties which yield introducing a series of canonical polynomials corresponding to the greatest common factor in the entries. These polynomials do satisfy a simple nonlinear recurrence which also yields algebraic elliptic curves, associated with biquadratic relations. In fact, these polynomials not only satisfy one recurrence but a whole hierarchy of recurrences. Remarkably these recurrences are universal: they are independent of q, the size of the matrices. This study provides examples of infinite dimensional integrable mappings.
QUARTET STATE OF THE TWO-DIMENSIONAL HEISENBERG MODEL WITH THE SPIN-½ ON A SQUARE LATTICE
Authors: BELINICHER V.I. , POPOVICH L.V.
Published: November 2004

The low-energy properties of the two-dimensional Heisenberg model with spin-½ on a square lattice are investigated on the basis of the local dimer order. The lattice is divided into square blocks consisting of the quartets of spins. The spin variables and the Heisenberg Hamiltonian are expressed in terms of the low-energy quartet variables. On the basis of the Dyson-Maleev representation, the spin-wave theory of the quartet state is developed. The spectrum of the lower magnon excitations consists of three degenerate modes with the energy gap Δ=0.17J. The ground state energy per spin E/N=−0.6J. Calculations of the basic corrections make the work complete.
EFFECTIVE DIPOLE-RADIATION-FIELD THEORY I: ONE-DIMENSIONAL OSCILLATOR BEYOND STANDARD COUPLING
Authors: DEKKER H.
Published: November 2004

A novel generalization is given of the standard dipole interaction between a charged particle and the electromagnetic field in the radiation gauge. The resulting nonlinear interaction problem is statistically linearized. The ensuing dynamics is solved exactly for a harmonically bound nonrelativistic electron in a finite region of three-dimensional space. The solution involves a generalized renormalization procedure and is free of runaway modes. The theory is particularly suited for a self-consistent treatment of the system's quantum mechanics. As a consequence of the generalized coupling an earlier noted ultraviolet quantum mechanical divergence is absent.
THERMODYNAMICS OF THE TODA CHAIN
Authors: CUCCOLI ALESSANDRO , LIVI ROBERTO , SPICCI MAURO , TOGNETTI VALERIO , VAIA RUGGERO
Published: November 2004

A review of the classical and quantum thermodynamic properties of the Toda chain is provided, together with a survey of the techniques that have been used to work them out, i.e., the bilateral Laplace transform method for the classical system, the Bethe–Ansatz and the variational path-integral approach for the quantum one. For the classical Toda chain we also recall some of the main dynamical features, i.e. the integrability of the model and the soliton-like solutions of the equations of motion. In the quantum case a comparison between the Bethe–Ansatz and the variational method is made. In particular it is shown as the latter offers the possibility of also evaluating static correlation functions.
SOLITON THEORY FOR CLASSICAL STATISTICAL MECHANICS OF THE MASSIVE-THIRRING-SINE-GORDON MODEL
Authors: CHUNG S. G.
Published: November 2004

This paper reviews soliton theories for classical statistical mechanics of the massive-Thirring-sine-Gordon model. These theories attempt not only to reproduce the classical transfer matrix method result but also to provide thermodynamic information about exact nonlinear excitations of the model. Three theories are discussed. Firstly, the soliton–gas phenomenology which is successful in the Toda lattice is shown to be not even approximately correct for the sine-Gordon model. This breakdown is due to the incorrect counting of the number of degrees of freedom. Secondly, the soliton–phonon theory which reproduces the WKB result is also shown to be not exact. This non-exactness is ascribed to the fact that the nonlinear phonons are not exact elementary excitations in the model. Thirdly, a non-gas phenomenological soliton–breather theory is derived as a classical limit of quantum statistical mechanics of the model. The exactness of the last theory is demonstrated through an accurate numerical analysis of its basic equations.
NON-GAUSSIAN ASYMPTOTIC BEHAVIOR OF RANDOM CONCENTRATION FIELDS WITH LONG TAILS
Authors: VLAD MARCEL OVIDIU
Published: November 2004

The asymptotic behavior of random scalar fields with long tails is analyzed. The problem is illustrated by considering the distribution of rare minerals (e.g. gold) on Earth crust. The main assumptions of the model are the following: a) the concentration field is generated by a random number of independent sources obeying nonhomogeneous Poisson statistics; b) the contribution of a source to the concentration field is a random function selected from a certain probability density functional; c) the moments of the contributions of a source have long tails with respect to the distance from the source. An analytical description of the random process described by these assumptions is possible: the generating functional of the concentration field as well as the cumulants of the concentration can be computed exactly. We distinguish two different regimes. If the average distance between two points is large enough, the finiteness of the system determines the asymptotic behavior and the random process is neither Gaussian nor of the Lévy type. This behavior is due to the long tails: they result in a partial overlapping of the contributions of the different sources to the concentration field, the fluctuations are strong and the superior cumulants do not vanish; however, as the system is finite they are also finite. If the average distance between two sources tends to zero, by using an appropriate length scale the system may be assumed to be infinite; the enhancement of fluctuations due to the overlapping is much bigger than in the first case, the cumulants become infinite and the stochastic process is of the Lévy type. The new approach can be applied to a large class of natural phenomena such as the shape of the fitness landscape in evolutionary biology, the stochastic gravitational fluctuations in astrophysics or the behavior of Langevin force fields in random media.
LAUGHLIN STATES AT THE EDGE
Authors: STONE MICHAEL , FISHER MATTHEW P. A.
Published: November 2004

An effective wavefunction for the edge excitations in the Fractional quantum Hall effect can be found by dimensionally reducing the bulk wavefunction. Treated this way the Laughlin ν = 1/(2n + 1) wavefunction yields a Luttinger model ground state. We identify the edge-electron field with a Luttinger hyper-fermion operator, and the edge electron itself with a non-backscattering Bogoliubov quasi-particle. The edge-electron propagator may be calculated directly from the effective wavefunction using the properties of a one-dimensional one-component plasma, provided a prescription is adopted which is sensitive to the extra flux attached to the electrons.
PRELIMINARY OPTICAL STUDY ON ER FLUIDS
Authors: ZHOU L. W. , YE J. F. , TAO R. B. , TANG Y. , PENG J. F. , GAO Z. , LIU L. Y. , MA S. H. , WANG W. C.
Published: November 2004

Linear and nonlinear optical study on electrorheological (ER) fluids is reported. The ER fluids under the investigation were glass beads, zeolite and ferroelectrics. The linear optical response of some ER fluids showed sharp changes near critical electric fields. An enhancement of electric field induced second harmonic generations (EFISH) was observed as the function of E2, where E is the external electric field. The said enhancement is considered to be corresponding to a modulation of the material's refractive index associated with the electric field induced polarization of the delocalized electrons. The enhanced nonlinear optical response on the transition between liquid and solid states can be related to the phase transition in ER fluids.
TWO-DIMENSIONAL BINGHAM PLASTIC FLOW IN A CYLINDRICAL PRESSURISED CLUTCH
Authors: ATKIN R. J. , CORDEN T. J. , KUM T. G. , BULLOUGH W. A.
Published: November 2004

An examination of the capability of an energised electro-rheological fluid to act as a rotating shaft seal is reported. A two-dimensional laminar flow model based on a Bingham plastic flowing between parallel plate electrodes indicated that leakage would always occur whenever the shaft was in rotation, whatever the magnitude of the pressure gradient along the sealing annulus. This result was confirmed in experiments, the results of which show some discrepancy between theory and experiment in the magnitude of the leakage rate. However this error is accountable and is acceptable in the area of immediate interest-shaft speed of circa 1000/1500 rpm and at maximum yield or electro-stress.
SIMULATION AND EXPERIMENTAL STUDY OF A SEMI-ACTIVE SUSPENSION WITH AN ELECTRORHEOLOGICAL DAMPER
Authors: WU X. M. , WONG J. Y. , STURK M. , RUSSELL D. L.
Published: November 2004

Various control strategies for a semi-active suspension system with an electrorheological (ER) damper were studied using computer simulation techniques, as well as experimentally using a quarter-car model test facility. The control strategies examined included those primarily designed for enhancing ride comfort and for improving road holding. It was found that the strategies designed for enhancing ride comfort do not necessarily provide improved road holding characteristics, and vice versa. Consequently, various composite control strategies for improving both ride comfort and road holding were investigated.

Experimental investigations showed that the damping characteristics of an electrorheological damper depend not only on the electrical field strength but also on the frequency of excitation. For the electrorheological fluid used in the study, the equivalent damping ratio decreases significantly with the increase in the frequency of excitation. This is primarily due to the fact that the shear ratio of the fluid used, which is the ratio of the shear strength at a given electrical field strength to that without applied electrical field, decreases with the increase in the shear rate. This behavior must be taken into account in the development of electrorheological dampers. Furthermore, at high frequencies, the duration of the applied voltage with any of the control strategies examined is very short. As a result, there is little difference in the measured performance of the semi-active suspension with different control strategies examined over a wide range of frequency. To achieve the potential of an ER fluid damper, improvements in the mechanical behavior of ER fluids are a key factor.
DISORDERING MECHANISMS OF THE Cu(110) SURFACE
Authors: MERIKOSKI J. , HÄKKINEN H. , MANNINEN M. , TIMONEN J. , KASKI K.
Published: November 2004

We review recent theoretical work on the various disordering mechanisms of the Cu(110) surface. In these studies the properties of the surface, from the onset of enhanced anharmonicity in surface vibrations up to bulk melting point T M , have been studied using molecular dynamics and lattice-gas Monte Carlo methods with many-body interactions derived from the effective medium theory. Well after the onset of enhanced out-of-plane surface vibrations, clustering of surface defects is found to induce a roughening transition at T≈0.81T M , and surface premelting is found to occur at T≈0.97T M . These results suggest, that these transitions can both appear at Cu(110). The general picture of disordering as reported here for Cu(110), is expected to be valid also for other unreconstructed (110) surfaces of fcc metals.
ENHANCEMENT EFFECT DUE TO HOP-ON AND HOP-OFF INTERACTION BETWEEN COOPER PAIR AND BIPOLARON ON THE CHARACTERISTICS OF THE HIGH-Tc CERAMIC SUPERCONDUCTOR
Authors: LAM C.C. , WONG K.N. , LEE C.M.
Published: November 2004

Enhancement in the critical temperature of high-Tc ceramic superconductors has been studied based on the bipolaronic theory which involves the hop-on and hop-off interaction between the Cooper pair and the bipolaron. As a consequence, the BCS energy gap is broadened to a certain extent which is determined by the interaction between the Cooper pair and the bipolaron. The effective superconducting energy gap for the ceramics consists of two parts: the traditional BCS energy gap of the ceramic and the gap broadening contributed by the hop-on and hop-off process. The critical temperature has been formulated from the effective BCS energy gap, and expressed in terms of the electronegativity difference Δχ. Results of our calculation on the critical temperature for MBCO-type, T(n) BCCO , and HBCCO match with the experimental data excellently. For a certain series of ceramic superconductors, the variation of Tc against Δχ traces out a curve having a high enough maximum value, in general.
ON THE EXCEPTIONAL STRUCTURE OF $End_{U_q sl_2 } \left( {V_N^{ \otimes n} } \right)$
Authors: MARTIN PAUL , SALEUR HUBERT
Published: November 2004

We show that the algebras [Formula: see text] and [Formula: see text] are Morita equivalent for any N, M, for n>1 provided that [Formula: see text]. Since all the generic structures are known, and the full structure of the N = 2 case is known, this completely determines the representation theory of all these algebras, including all unitarizable and non-unitarizable exceptional cases.
CHAOTIC BEATS IN A MODIFIED CHUA'S CIRCUIT: DYNAMIC BEHAVIOR AND CIRCUIT DESIGN
Authors: CAFAGNA DONATO , GRASSI GIUSEPPE
Published: November 2004

This paper illustrates the recent phenomenon of chaotic beats in a modified version of Chua's circuit, driven by two sinusoidal inputs with slightly different frequencies. In order to satisfy the constraints imposed by the beats dynamics, a novel implementation of the voltage-controlled characteristic of the Chua diode is proposed. By using Pspice simulator, the behavior of the designed circuit is analyzed both in time-domain and state-space, confirming the chaotic nature of the phenomenon and the effectiveness of the approach.
TWO IMPULSIVE SYNCHRONIZATION STUDIES USING SC-CNN-BASED CIRCUIT AND CHUA'S CIRCUIT
Authors: KILIÇ RECAI , ALÇI MUSTAFA , GÜNAY ENIS
Published: November 2004

The impulsive synchronization method has been applied to several well-known chaotic circuits and systems such as Chua's circuit, Lorenz system and hyperchaotic circuit in the literature. In this paper, we also present two impulsive synchronization studies using SC-CNN-based circuit and Chua's circuit. In the first study, we have investigated the impulsive synchronization between two SC-CNN-based circuits. Pspice simulation results show that two SC-CNN-based circuits can be synchronized impulsively via x1 and x2 cell dynamics for different impulse width and impulse period values. And in the second study, we have investigated the impulsive synchronization between SC-CNN-based circuit and Chua's circuit. Pspice simulation results verify that two chaotic circuits, which have identical dynamical systems via appropriate parameter transformations but having quite different hardware implementations, can be synchronized impulsively for different impulse width and impulse period values.
A SUFFICIENT CONDITION FOR THE UNIQUENESS OF NORMAL FORMS AND UNIQUE NORMAL FORMS OF GENERALIZED HOPF SINGULARITIES
Authors: PENG JIANPING , WANG DUO
Published: November 2004

A sufficient condition for the uniqueness of the Nth order normal form is provided. A new grading function is proposed and used to prove the uniqueness of the first-order normal forms of generalized Hopf singularities. Recursive formulas for computation of coefficients of unique normal forms of generalized Hopf singularities are also presented.
NEWTON'S VERSUS HALLEY'S METHOD: A DYNAMICAL SYSTEMS APPROACH
Authors: ROBERTS GARETH E. , HORGAN-KOBELSKI JEREMY
Published: November 2004

We compare the iterative root-finding methods of Newton and Halley applied to cubic polynomials in the complex plane. Of specific interest are those "bad" polynomials for which a given numerical method contains an attracting cycle distinct from the roots. This implies the existence of an open set of initial guesses whose iterates do not converge to one of the roots (i.e. the numerical method fails). Searching for a set of bad parameter values leads to Mandelbrot-like sets and interesting figures in the parameter plane. We provide some analytic and geometric arguments to explain the contrasting parameter plane pictures. In particular, we show that there exists a sequence of parameter values λn for which the corresponding numerical method has a superattracting n cycle. The λn lie at the centers of a converging sequence of Mandelbrot-like sets.
MULTIGRID-CONJUGATE GRADIENT TYPE METHODS FOR REACTION–DIFFUSION SYSTEMS
Authors: CHANG S.-L. , CHEN H.-S. , CHIEN C.-S.
Published: November 2004

We study multigrid methods in the context of continuation methods for reaction–diffusion systems, where the Bi-CGSTAB and GMRES methods are used as the relaxation scheme for the V-cycle, W-cycle and full approximation schemes, respectively. In particular, we apply the results of Brown and Walker [1997] to investigate how the GMRES method can be used to solve nearly singular systems that occur in continuation problems. We show that for the sake of switching branches safely, one would rather solve a perturbed problem near bifurcation points. We propose several multigrid-continuation algorithms for curve-tracking in nonlinear elliptic eigenvalue problems. Our numerical results show that the algorithms proposed have the advantage of being robust and easy to implement.
DETECTION OF LIMIT CYCLE BIFURCATIONS USING HARMONIC BALANCE METHODS
Authors: ROBBIO FEDERICO I. , ALONSO DIEGO M. , MOIOLA JORGE L.
Published: November 2004

In this paper, bifurcations of limit cycles close to certain singularities of the vector fields are explored using an algorithm based on the harmonic balance method, the theory of nonlinear feedback systems and the monodromy matrix. Period-doubling, pitchfork and Neimark–Sacker bifurcations of cycles are detected close to a Gavrilov–Guckenheimer singularity in two modified Rössler systems. This special singularity has a zero eigenvalue and a pair of pure imaginary eigenvalues in the linearization of the flow around its equilibrium. The presented results suggest that the proposed technique can be promising in analyzing limit cycle bifurcations arising in the unfoldings of other complex singularities.
A WAVE APPROACH TO PATTERN RECOGNITION (WITH APPLICATION TO OPTICAL CHARACTER RECOGNITION)
Authors: BIKTASHEV VADIM , KRINSKY VALENTIN , HAKEN HERMANN
Published: November 2004

The possibility of using nonlinear media as a highly parallel computation tool is discussed, specifically for image classification and recognition. Some approaches of this type are known, that are based on stationary dissipative structures which can “measure” scalar products of images. In this paper, we exploit the analogy between binary images and point sets, and use the Hausdorff metrics for comparing the images. It does not require the measure at all, and is based only on the metrics of the space whose subsets we consider.

In addition to Hausdorff distance, we suggest a new “nonlinear” version of this distance for comparison of images, called “autowave” distance. This distance can be calculated very easily and yields some additional advantages for pattern recognition (e.g. noise tolerance).

The method was illustrated for the problem of machine reading (Optical Character Recognition). It was compared with some famous OCR programs for PC. On a medium quality xerocopy of a journal page, in the same conditions of learning and recognition, the autowave approach resulted in much fewer mistakes.

The method can be realized using only one chip with simple uniform connection of the elements. In this case, it yields an increase in computation speed of several orders of magnitude.
INTENSITY PROBABILITY DISTRIBUTION OF SPIKING-MODE OSCILLATIONS IN LASERS: POWER-LAW UNIVERSALITY
Authors: ISHIYAMA FUMIHIKO , OTSUKA KENJU
Published: November 2004

We theoretically investigated the probability distributions of the output intensity of lasers with external perturbations. These perturbations were loss modulation and incoherent delayed feedback. We found that the intensity probability distributions usually obey a distinct power-law in spiking-mode oscillations both in periodic and chaotic regimes.
NONLINEAR VIBRATIONS IN AN AGRICULTURAL IMPLEMENT SYSTEM
Authors: SAKAI KENSHI , AIHARA KAZUYUKI
Published: November 2004

Vibrations in an agricultural implement system composed of a tractor and a subsoiler are analyzed from the viewpoint of nonlinear dynamics. The time series data of acceleration experimentally obtained are classified to chaotic and periodic vibrations with reconstruction of possible attractors and with deterministic nonlinear prediction.
NONUNIFORM NONLINEAR OSCILLATIONS OF A DOMAIN WALL IN UNIAXIAL FERROMAGNET
Authors: POPKOV A.F. , YAREMA I.P. , ELEONSKY V.M.
Published: November 2004

The nonlinear small amplitude excitations of a domain wall (DW) in the ferromagnet with high uniaxial anisotropy are investigated using reduced magnetodynamic equations. The “life-time” of soliton-like oscillations of DW in the nondissipative media is defined. The conditions of direct and parametric stabilization of self-localized DW oscillations by alternating magnetic fields are analyzed in the presence of dissipation.
KNOTTED PERIODIC ORBITS IN CHUA’S CIRCUIT
Authors: KOCAREV Lj. , TASEV Z. , DIMOVSKI D. , CHUA L.O.
Published: November 2004

Induced templates for two members of Chua’s attractors: spiral-type and double-scroll chaotic attractors are computed using the orbits of lower period. The template describes the topological properties of periodic orbits embedded in the attractor. It is identified by a set of integers which characterize the attractor. The templates are confirmed by investigating orbits of higher period.
NONLINEAR DYNAMICS OF DIGITAL PHASE-LOCKED LOOPS WITH DELAY
Authors: VIEIRA MARIA DE SOUSA , LICHTENBERG ALLAN J. , LIEBERMAN MICHAEL A.
Published: November 2004

We investigate numerically and analytically the nonlinear dynamics of a system consisting of two self-synchronizing pulse-coupled nonlinear oscillators with delay. The particular system considered consists of connected digital phase-locked loops. We find mapping equations that govern the system and determine the synchronization properties. We study the bifurcation diagrams, which show regions of periodic, quasiperiodic and chaotic behavior, with unusual bifurcation diagrams, depending on the delay. We show that depending on the parameter that is varied, the delay will have a synchronizing or desynchronizing effect on the locked state. The stability of the system is studied by determining the Liapunov exponents, indicating marked differences compared to coupled systems without delay.
CONSTRUCTING HOMOCLINIC ORBITS AND CHAOTIC ATTRACTORS
Authors: DENG BO
Published: November 2004

Homoclinic orbits and chaotic attractors are constructed progressively by singular perturbations. More specifically, lower dimensional slow subsystems and fast subsystems are constructed separately as building blocks. The former are then modulated onto the latter via homotopy. This gives a systematic way to implement Rössler’s dual principle for mathematical modeling. Systems constructed in this way are simple, robust, and ideal for the purposes of experimental and theoretical analyses.
GLOBAL BEHAVIOR OF THE CHARGED ISOSCELES THREE-BODY PROBLEM
Authors: ATELA PAU , McLACHLAN ROBERT I.
Published: November 2004

We study the global bifurcation diagram of the two-parameter family of ODE’s that govern the charged isosceles three-body problem. (The classic isosceles three-body problem and the anisotropic Kepler problem (two bodies) are included in the same family.) There are two major sources of periodic orbits. On the one hand the “Kepler” orbit, a stable orbit exhibiting the generic bifurcations as the multiplier crosses rational values. This orbit turns out to be the continuation of the classical circular Kepler orbit. On the other extreme we have the collision-ejection orbit which exhibits an “infinite-furcation.” Up to a limiting value of the parameter we have finitely many periodic orbits (for each fixed numerator in the rotation number), passed this value there is a sudden birth of an infinite number of them. We find that these two bifurcations are remarkably connected forming the main “skeleton” of the global bifurcation diagram. We conjecture that this type of global connection must be present in related problems such as the classic isosceles three-body problem and the anisotropic Kepler problem.
MODE INTERACTIONS WITH SPHERICAL SYMMETRY
Authors: CASTRO S.B.S.D.
Published: November 2004

We study mode interaction steady-state bifurcation problems with spherical symmetry. Using the representation of O(3) in terms of spherical harmonics, we study the interactions of the modes of dimension 1, 3 and 5. When studying mode interactions involving the 3- and the 5-dimensional modes, we come across a very natural representation, which turns out to be that of SO(3) instead of O(3). Given that the study of problems with this latter symmetry has already been done, we then study problems with SO(3) symmetry. For all these problems, we stress the existence of secondary bifurcations giving rise to the existence of limit cycles and the occurrence of heteroclinic connections between equilibria.
EXPERIMENTAL EVIDENCE FOR SYNCHRONOUS BEHAVIOR OF CHAOTIC NONLINEAR OSCILLATORS WITH UNIDIRECTIONAL OR MUTUAL DRIVING
Authors: RÍO EZEQUIEL DEL , VELARDE MANUEL G. , RODRÍGUEZ-LOZANO ANGEL , RUL’KOV NIKOLAI F. , VOLKOVSKII ALEXANDER R.
Published: November 2004

Experimental evidence is provided for the synchronization of chaotic self-excited oscillators and chaotic synchronous response. With unidirectional coupling between two chaotic nonlinear circuits, synchronous chaotic oscillations can result from either forced synchronization or the response phenomenon. With mutual coupling, two originally chaotic oscillators can become time periodic, a result that we have shown to persist for values of the coupling down to noise level.
RESONANTLY FORCED SURFACE WAVES IN A NATTERER TUBE: PATTERNS, DEFECTS AND SQUEEZES
Authors: GONZÁLEZ-VIÑAS W. , SALÁN J.
Published: November 2004

Experimental results on interfacial waves forced periodically and perpendicular to gravity which appear in a Natterer tube are presented. If the control parameter is moved, the patterns stamped by these waves will evolve with defects and more complex structures appearing, which lead to chaos. Also, squeezes (a few drops produced by squeezing) appear that move along the tube and interact with each other.