bluuebunny/crossref_metadata_2025 huggingface dataset:
PROPERTIES OF AN ALTERNATE LAX DESCRIPTION OF THE KdV HIERARCHY
Authors: BRUNELLI J.C. , DAS ASHOK
Published: November 2004

We study systematically the Lax description of the KdV hierarchy in terms of an operator which is the geometrical recursion operator. We formulate the Lax equation for the nth flow and construct the Hamiltonians which lead to commuting flows. In this formulation, the recursion relation between the conserved quantities follows naturally. We give a simple and compact definition of all the Hamiltonian structures of the theory which are related through a power law.
IMPLICATIONS OF THE RECENT TOP QUARK DISCOVERY ON TWO-HIGGS DOUBLET MODEL
Authors: PARK GYE T.
Published: November 2004

Concentrating on the impact of the very recent top quark discovery, we perform a combined analysis of two strongest constraints on the two-Higgs doublet model, one coming from the recent measurement by CLEO on the inclusive branching ratio of b→sγ decay and the other from the recent LEP data on [Formula: see text] decay. We have included the model predictions for one-loop vertex corrections to [Formula: see text] through εb. We find that the εb constraint excludes most of the less appealing window: tan β≲1 at 95% C.L. for the measured top mass mt=176±8±10 GeV from CDF. Moreover, it excludes tan β≲2 at 95% C.L. for mt≳176 GeV; combined with the b→sγ constraint, only very heavy charged Higgs (≳670 GeV) is allowed by the measured mt from CDF.
EFFECTIVE POTENTIALS AND SYMMETRY RESTORATION IN THE CHIRAL ABELIAN HIGGS MODEL
Authors: ANDERSEN JENS O.
Published: November 2004

The chiral Abelian Higgs model is studied at finite temperature. By integrating out the heavy modes, we make a three-dimensional effective theory for the static modes. It is demonstrated that the plasma masses are correctly reproduced to leading order in m2/T2. The effective potential for the composite operator ɸ†ɸ is calculated at one-loop for the resulting three-dimensional theory and it is shown that the result is gauge parameter independent. The numerical investigation of the potential reveals that the symmetry is restored via a first-order phase transition. Comparison with the ordinary ring improved potential is made and it is found that the barrier height at Tc is somewhat higher.
FINITE SIZE EFFECTS IN CHARGED PARTICLE SPECTRA IN CENTRAL S+S COLLISIONS AT 200 GeV/c PER NUCLEON
Authors: GORENSTEIN M.I. , MILLER H.G. , RITCHIE R.A.
Published: November 2004

The inclusion of finite size effects in a single temperature Maxwell—Boltzmann, which inspired model calculation of pT distributions of h− and proton spectra, leads to an enhancement at low values of pT. In the case of h− spectra this increase is consistent with the recent measurements of S+S at 200 GeV/c per nucleon. The calculated increase at low values of pT in the proton spectra occurs at small values of the transverse kinetic energy which are not accessible in the recent experimental results.
DETERMINATION OF THE HIGGS BOSON MASS BY THE CANCELLATION OF ULTRAVIOLET DIVERGENCES IN THE SU(2)L⊗U(1) THEORY
Authors: CASTRO GABRIEL LÓPEZ , PESTIEAU JEAN
Published: November 2004

We assume the vanishing of the quadratic divergences in the SU(2)L⊗U(1) electroweak theory. Using the top mass value reported recently by the CDF collaboration mt= 176±8±10 GeV, we predict the mass of the Higgs boson to be mH=321±29 GeV. If we assume the vanishing of both quadratic and logarithmic divergences of the top self-mass, we predict mt=170.5±0.3 GeV and mH=308.6±0.7 GeV.
HEAVY FLAVOR PRODUCTION
Authors: BESSON DAVE Z.
Published: November 2004

Recent highlights in the production of charm, bottom, and top quarks, are very briefly covered.
THE PARTON DISTRIBUTIONS IN NUCLEONS: A QUARK MODEL ANALYSIS
Authors: TRAINI MARCO , ZAMBARDA ANDREA , VENTO VICENTE
Published: November 2004

We use a laboratory frame description based on quark model wave functions to study the parton distributions in the nucleon. The present approach incorporates two major improvements, namely, it has the correct support and the renormalization group evolution is carried out to next-to-leading order. We obtain initially the parton distributions arising from the Isgur-Karl wave function. The failure of the latter to reproduce, even approximately, the data motivates us to analyze different scenarios, i.e. additional high momentum components and nonvanishing gluon distributions at the initial scale. We conclude that in order to understand data at various scales complex models simultaneously, it is necessary to include high momentum components and/or valence gluons.
SOME PHYSICAL CONSEQUENCES OF THE GENERAL DEFORMATIONS
Authors: BANG HA HUY
Published: November 2004

The generalized deformed uncertainty principle is derived and the connections of some deformed quantities with the usual ones are studied. Furthermore, taking into consideration the expressions of the quantum fields in terms of the generalized deformed oscillators we can find some special deformations, in which the corresponding deformed quantum fields are local and deformed oscillators are linear.
COALESCED ABELIAN BOSONIZATION
Authors: BOENKOST WOLFRAM , CONSTANTINESCU FLORIN
Published: November 2004

We extend the Abelian bosonization by letting some fermionic as well as bosonic fields coincide (coalesce). To achieve this we use a generalization of the Cauchy determinant formula.
THE SOLAR NEUTRINO PROBLEM AND BOUNDS ON SOLAR NEUTRINO FLUXES
Authors: KWONG WAIKWOK , ROSEN S.P.
Published: November 2004

We review the current status of the solar neutrino problem. A survey of the experiments and their results are given, and solar physics crucial to the understanding of these results are discussed. Semi-empirical methods are used to derive bounds on the fluxes of the three most important components (pp, 7Be and 8B) of the solar neutrino spectrum. The 8B neutrinos are directly measured to be about half of the theoretical prediction. Relative to their theoretical predictions, we find the 7Be neutrinos to be highly suppressed and the pp neutrinos not suppressed. We are also able to derive a lower bound on the pp flux.
QUANTUM GRAVITY WITH BOUNDARIES NEAR TWO DIMENSIONS
Authors: AIDA TOSHIAKI , KITAZAWA YOSHIHISA
Published: November 2004

We evaluate the quantum corrections of the Einstein-Hilbert action with boundaries in (2+ε)-dimensional expansion approach. We find the Einstein-Hilbert action with boundaries to be renormalizable to the one-loop order. We compute the geometric entropy beyond the semiclassical approximation. It is found that the exact geometric entropy is related to the string susceptibility by the analytic continuation in the central charge. Our results also show that we can renormalize the divergent quantum corrections for the Bekenstein-Hawking entropy of black holes by the gravitational coupling constant renormalization beyond two dimensions.
CHIRAL BOSONS AS SOLUTIONS OF THE BV MASTER EQUATION FOR 2-D CHIRAL GAUGE THEORIES
Authors: BRAGA N.R.F. , MONTANI H.
Published: November 2004

We construct the chiral Wess-Zumino term as a solution for the Batalin-Vilkovisky master equation for anomalous two-dimensional gauge theories, working in an extended field-antifield space, where the gauge group elements are introduced as additional degrees of freedom. We analyze the Abelian and the non-Abelian cases, calculating in both cases the BRST generator in order to show the physical equivalence between this chiral solution for the master equation and the usual (nonchiral) one.
A LINK INVARIANT FROM QUANTUM DILOGARITHM
Authors: KASHAEV R.M.
Published: November 2004

The link invariant, arising from the cyclic quantum dilogarithm via the particular R- matrix construction is proved to coincide with the invariant of triangulated links in S3 introduced in Ref. 14. The obtained invariant, like Alexander-Conway polynomial, vanishes on disjoint union of links. The R-matrix can be considered as the cyclic analog of the universal R-matrix associated with Uq(sl(2)) algebra.
NONRENORMALIZABILITY MAY BE SUPERFICIAL IN THE COVARIANT FORMALISM OF QUANTUM GRAVITY
Authors: ABE MITSUO , NAKANISHI NOBORU
Published: November 2004

It is pointed out that the nonrenormalizability of quantum Einstein gravity may be caused by the inadequacy of the conventional perturbative approach. It is more reasonable to reconsider the problem in the light of a newly proposed perturbative scheme, which is free of the ad hoc assumption on which the conventional perturbation theory is based. It is explicitly shown that there is a gravity-theory example which is nonrenormalizable in the usual sense but completely finite if the new perturbative scheme is applied.
FREE ENERGY DECREASES ALONG WILSON RENORMALIZATION GROUP TRAJECTORIES
Authors: PERIWAL VIPUL
Published: November 2004

The free energy is shown to decrease along Wilson renormalization group trajectories, in a dimension-independent fashion, for d>2. The argument assumes the monotonicity of the cutoff function, and positivity of a spectral representation of the two-point function. The argument is valid for all orders in perturbation theory.
THE VERTEX CORRECTIONS IN TECHNICOLOR MODEL WITHOUT EXACT CUSTODIAL SYMMETRY
Authors: YOSHIKAWA TADASHI
Published: November 2004

We discuss the effects of isospin breaking which appear in the vertex corrections for [Formula: see text], Zτ+τ− and Wντ in a one-family technicolor model without exact custodial symmetry. By means of the effective Lagrangian approach we compute the vertex corrections for [Formula: see text], Zττ and Wτν. When the isospin symmetry in technilepton sector is not exact and there are a few lighter technivector mesons that are composed by technileptons, the technivector mesons contribute to the vertex corrections. It would be the evidence of the isospin breaking when the difference of the vertex corrections between Zττ and Wτν is measured.
SUPERSYMMETRY, VARIATIONAL METHOD AND HULTHÉN POTENTIAL
Authors: FILHO ELSO DRIGO , RICOTTA REGINA MARIA
Published: November 2004

The formalism of supersymmetric quantum mechanics provides us with the eigenfunctions to be used in the variational method to obtain the eigenvalues for the Hulthén potential.
HIGH TEMPERATURE EXPANSION OF STRING FREE ENERGY IN HYPERBOLIC SPACE
Authors: BYTSENKO A.A. , ODINTSOV S.D. , ZERBINI S.
Published: November 2004

The high temperature behavior of the open bosonic string free energy in the space S1 ⊗ HN with vanishingly small curvature is investigated. The leading term of the high temperature expansion of the one-loop free energy, near the Hagedorn instability, is obtained. The problem of ir regularization of thermodynamical quantities is pointed out. For minimally coupling quantum fields related to the normal modes of strings, the results are similar to the ones valid for Rindler space. In the lower mass string states regime a connection with the quantum corrections to the black hole entropy is outlined.
SPIN STRUCTURE OF THE PROTON
Authors: WU CHUNG-YI
Published: November 2004

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton’s spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global leading-order QCD fit to obtain the spin-dependent quark distributions, which could be used as input for analyzing lepton-hadron and hadron-hadron collisions.
REPRODUCTION OF THE NUCLEON SPIN EXPERIMENTAL DATA FROM THE IMPROVED ELLIS-JAFFE SUM RULES
Authors: LIU JUEPING
Published: November 2004

The proton, neutron and deuteron spin experimental data obtained so far are reproduced by using the improved Ellis-Jaffe sum rules, the spin structure of nucleon is then analyzed by assuming that the orbit angular momentum of the partons inside the nucleon is vanishing at a not very large energy scale.
AN EFFECTIVE STRONG GRAVITY INDUCED BY QCD
Authors: BRINDEJONC VINCENT , COHEN-TANNOUDJI GILLES
Published: November 2004

We show that, when quantized on a “curved intra-hadronic spacetime”, QCD induces an effective gravitation-like interaction with gravitational and cosmological constants in the GeV range.
ALL CONFORMAL INVARIANT REPRESENTATIONS OF d-DIMENSIONAL ANTI-DE SITTER GROUP
Authors: METSAEV R.R.
Published: November 2004

All the irreducible representations of the anti-de Sitter group which are relevant for elementary particles and which can be realized as irreducible representations of the conformal group are found. It is shown that all these representations correspond to massless representations which arise from considerations of gauge invariance. The problem is studied for arbitrary d>2 dimensional anti-de Sitter group.
TC CORRECTIONS TO $b\bar{b}$ PRODUCTION IN e+e− ANNIHILATION
Authors: LU GONG-RU , XIAO ZHEN-JUN , LI HAI-BO , YANG YA-DONG
Published: November 2004

We calculated the TC [Formula: see text] corrections to bottom quark production at high energy e+e− colliders in one generation TC model. We found that the corrections to the total cross-section can reach −2.6% level for favorable parameter values. For the forward-backward and left-right asymmetries, the effects are small (<1%) except for the large top mass and small PGBs mass.
CONSTRAINTS ON NO-SCALE SUPERGRAVITY MODELS
Authors: KELLEY S. , LOPEZ JORGE L. , NANOPOULOS D.V. , ZICHICHI A.
Published: November 2004

We revisit the no-scale mechanism in the context of the simplest no-scale supergravity extension of the standard model. This model has the usual four-dimensional parameter space plus an additional parameter ξ3/2≡m3/2/m1/2. We show how predictions of the model may be extracted over the whole parameter space. A necessary condition for the potential to be stable is Str ℳ4>0. In a class of no-scale supergravity models this condition implies [Formula: see text]. We also calculate the residual vacuum energy at the unification scale [Formula: see text], and find that in typical models one must require C0> 10. Such constraints may be important in the search for a realistic string no-scale supergravity model.
A RENORMALIZATION GROUP IMPROVED NONLOCAL GRAVITATIONAL EFFECTIVE LAGRANGIAN
Authors: ELIZALDE E. , ODINTSOV S.D.
Published: November 2004

Renormalization group techniques are used in order to obtain the improved nonlocal gravitational effective action corresponding to any asymptotically free GUT, up to invariants which are quadratic on the curvature. The corresponding nonlocal gravitational equations are written down, both for the case of asymptotically free GUTs and also for quantum R2-gravity. The implications of the results when obtaining the flux of vacuum radiation through the future null infinity are briefly discussed.
LIMIT ON A HEAVY DIRAC NEUTRINO THROUGH OBLIQUE RADIATIVE CORRECTIONS
Authors: NATALE A.A. , DA SILVA P.S. RODRIGUES
Published: November 2004

We compute the one-loop oblique corrections in a typical model with neutrino masses due to the seesaw mechanism. We verify that a Dirac neutrino mass up to 178 GeV is still allowed by the experimental data.
HIGHER SPIN REALIZATIONS OF THE BOSONIC STRING
Authors: LÜ H. , POPE C.N. , XU K.W.
Published: November 2004

It has been shown that certain W algebras can be linearized by the inclusion of a spin-one current. This provides a way of obtaining new realizations of the W algebras. Recently such new realizations of W3 were used in order to embed the bosonic string in the critical and noncritical W3 strings. In this letter, we consider similar embeddings in W2,4 and W2,6 strings. The linearization of W2,4 is already known, and can be achieved for all values of central charge. We use this to embed the bosonic string in critical and noncritical W2,4 strings. We then derive the linearization of W2,6 using a spin-one current, which turns out to be possible only at central charge c=390. We use this to embed the bosonic string in a noncritical W2,6 string.
DO THE PRESENT ELECTROWEAK PRECISION MEASUREMENTS LEAVE ROOM FOR EXTRA GENERATIONS?
Authors: NOVIKOV V.A. , OKUN L.B. , ROZANOV A.N. , VYSOTSKY M.I. , YUROV V.P.
Published: November 2004

The recent data on Z boson decays and on the W mass are analyzed from the point of view of the possible existence of extra generations of leptons and quarks with masses ≳mz/2. Present experimental accuracy is not sufficient to exclude the existence of one extra generation of leptons and quarks, even with masses as low as 50 GeV.
SUCCESSIVE SUPERALGEBRAIC TRUNCATIONS FROM THE MAXIMAL SUPERGRAVITY IN FOUR DIMENSIONS
Authors: KIM CHANG-HO , PARK YOUNG-JAI , KIM YONGDUK
Published: November 2004

We study the four-dimensional N=8 maximal supergravity in the context of Lie superalgebra SU(8/1). All possible successive superalgebraic truncations from four-dimensional N=8 theory to N=7, 6, …, 1 supergravity theories are systematically realized as sub-superalgebra chains of SU(8/1) by using the Kac-Dynkin weight techniques.
INFLATON POTENTIAL RECONSTRUCTION AND GENERALIZED EQUATIONS OF STATE
Authors: MANGANO G. , MIELE G. , STORNAIOLO C.
Published: November 2004

We extend a previous analysis concerning cosmological fluids with generalized equations of state in order to study inflationary scenarios. In the framework of the slow-roll approximation we find the expressions for the perturbation parameters ε, η and the density perturbation spectra in terms of the adiabatic index γ(a) as a function of the universe scale factor. This connection allows one to find straightforwardly γ(a) corresponding, for example, to the simplest chaotic model and to the Harrison-Zeldovich potential and shows its capability to be applied to more complicated situations. Finally, we use this description to develop a new approach to the early universe dynamics, based on a 1/N expansion, where N is the e-fold number. To this end, we introduce a set of suitable dimensionless variables and show that at the zeroth order in /1N, an improved slow-roll approximation is obtained.
ELECTROMAGNETIC FIELD IN SOME ANISOTROPIC STIFF FLUID UNIVERSES
Authors: PIMENTEL LUIS O.
Published: November 2004

The electromagnetic field is studied in a family of exact solutions of the Einstein equations whose material content is a perfect fluid with stiff equation of state (p=ε). The field equations are solved exactly for several members of the family.
MIRROR BIREFRINGENCE IN A FABRY-PEROT CAVITY AND THE DETECTION OF VACUUM BIREFRINGENCE IN A MAGNETIC FIELD
Authors: CHUI T.C.P. , SHAO M. , REDDING D. , GURSEL Y. , BODEN A.
Published: November 2004

Quantum electrodynamics (QED) theory predicts that vacuum under the influence of a strong magnetic field is birefringence. Recently, several groups have proposed to used a high finesse Fabry—Perot cavity to increase the average path length of the light in the magnetic field. This together with the state-of-the-art dipole magnets, should bring the effect within reach of observation. However, the mirrors used in the FP are known to have intrinsic birefringence which is of orders of magnitude larger than the birefringence of the vacuum. In this letter, we analyze the effect of uncontrollable variations of mirror birefringence on two recently proposed optical schemes. The first scheme,1 which we called the frequency scheme, is based on measurement of the beat frequency of two orthogonal polarized laser beams in the cavity. We show that mirror birefringence contributes to the detection uncertainties in first order, resulting in a high susceptibility to variations of its value. In the second scheme, which we called the polarization scheme, laser polarized at 45° relative to the B-field is injected into the cavity. The ellipticity and polarization rotation of the light exiting the cavity is measured.2 Under this scheme, mirror birefringence contributes as a correction of the QED effect, greatly reducing its sensitivity to the undesirable changes.
O(4) SYMMETRIC SINGULAR SOLUTIONS AND MULTIPARTICLE CROSS-SECTIONS IN Φ4 THEORY AT TREE LEVEL
Authors: BEZRUKOV F.L. , LIBANOV M.V. , TROITSKY S.V.
Published: November 2004

We solve the classical Euclidean boundary value problem for tree-level multiparticle production in Φ4 theory at arbitrary energies in the case of O(4) symmetric field configurations. We reproduce the known low-energy results and obtain a lower bound on the tree cross-sections at arbitrary energies.
HAMILTONIAN REDUCTION AND SUPERSYMMETRIC TODA MODELS
Authors: AU G. , SPENCE B.
Published: November 2004

New formulations of the solutions of N=1 and N=2 super-Toda field theory are introduced, using Hamiltonian reduction of the N=1 and N=2 super-WZNW models to the super-Toda models. These parametrizations are then used to present the Hamiltonian formulations of the super-Toda theories on the spaces of solutions.
ON FIELD THEORIES OF LOOPS
Authors: NAKAZAWA NAOHITO
Published: November 2004

We apply stochastic quantization method to real symmetric matrix models for the second quantization of nonorientable loops in both discretized and continuum levels. The stochastic process defined by the Langevin equation in loop space describes the time evolution of the nonorientable loops defined on nonorientable 2-D surfaces. The corresponding Fokker-Planck Hamiltonian deduces a nonorientable string field theory at the continuum limit.
GENERALIZED DEFORMED su(2) ALGEBRAS, DEFORMED PARAFERMIONIC OSCILLATORS AND FINITE W-ALGEBRAS
Authors: BONATSOS D. , KOLOKOTRONIS P. , DASKALOYANNIS C.
Published: November 2004

Several physical systems (two identical particles in two dimensions, isotropic oscillator and Kepler system in a two-dimensional curved space) and mathematical structures (quadratic algebra QH(3), finite W-algebra [Formula: see text]) are shown to possess the structure of a generalized deformed su (2) algebra, the representation theory of which is known. Furthermore, the generalized deformed parafermionic oscillator is identified with the algebra of several physical systems (isotropic oscillator and Kepler system in two-dimensional curved space, Fokas-Lagerstrom, Smorodinsky-Winternitz and Holt potentials) and mathematical constructions (generalized deformed su (2) algebra, finite W-algebras [Formula: see text] and [Formula: see text]). The fact that the Holt potential is characterized by the [Formula: see text] symmetry is obtained as a by-product.
EXACT SOLVABILITY OF THE CALOGERO AND SUTHERLAND MODELS
Authors: RÜHL WERNER , TURBINER ALEXANDER
Published: November 2004

Translationally invariant symmetric polynomials as coordinates for N-body problems with identical particles are proposed. It is shown that in those coordinates the Calogero and Sutherland N-body Hamiltonians, after appropriate gauge transformations, can be presented as a quadratic polynomial in the generators of the algebra sl N in finitedimensional degenerate representation. The exact solvability of these models follows from the existence of the infinite flag of such representation spaces, preserved by the above Hamiltonians. A connection with Jack polynomials is discussed.
SUPERDIFFEOMORPHISMS OF THE TOPOLOGICAL YANG-MILLS AND RENORMALIZATION
Authors: ZERROUKI H.
Published: November 2004

We give the superdiffeomorphisms transformations of the four-dimensional topological Yang-Mills theory in curved manifold and discuss the uv renormalization of the model. The explicit expression of the most general counterterm is given.
SOLVING NONPERTURBATIVE FLOW EQUATIONS
Authors: ADAMS J. , TETRADIS N. , BERGES J. , FREIRE F. , WETTERICH C. , BORNHOLDT S.
Published: November 2004

Nonperturbative exact flow equations describe the scale dependence of the effective average action. We present a numerical solution for an approximate form of the flow equation for the potential in a three-dimensional N-component scalar field theory. The critical behavior, with associated critical exponents, can be inferred with good accuracy.
DILATON GRAVITY COUPLED TO A NONLINEAR SIGMA MODEL IN 2+ε DIMENSIONS
Authors: KOJIMA SHIN-ICHI , SAKAI NORISUKE , TANII YOSHIAKI
Published: November 2004

Quantum theory of dilaton gravity coupled to a nonlinear sigma model with a maximally symmetric target space is studied in 2+ε dimensions. The uv stable fixed point for the curvature of the nonlinear sigma model demands a new fixed point theory for the dilaton coupling function. The fixed point of the dilaton coupling is a saddle point similarly to the previous case of the flat target space.
ON THE POSSIBILITY OF CONSTRUCTING COVARIANT CHROMOMAGNETIC FIELD MODELS
Authors: CABO ALEJANDRO , PEÑARANDA SIANNAH , MARTINEZ RENE
Published: November 2004

Expressions for SO(4) invariant Euclidean QCD generating functionals are introduced which should produce nonvanishing gluon condensates. We consider first the loop expansion of the corresponding effectíve action searching for a description differing from the usual perturbation theory. At this level, we consider special free propagators which have off-diagonal long range order. The calculation of the polarization tensor leads to a gluon mass term which is proportional to the squared root of the finite value for . The summation of all the one-loop contributions to the energy having only mass insertions, indicates the spontaneous generation of the condensate from the perturbative ground state in a way resembling the similar effect in the case of chromomagnetic field models.
W-EXTENSIONS OF THE FRAPPAT et al. SYMMETRIES AND FIELD THEORETICAL REALIZATIONS ON THE TORUS
Authors: SAIDI E.H. , SEDRA M.B. , SERHANI A.
Published: November 2004

A new extension of the standard Virasoro algebra as well as its W-generalizations containing the Antoniadis et al. and Frappat et al. symmetries (Refs. 8 and 9 as special cases), are obtained. The fundamentals of the quantum field theory representation of the Frappat et al. symmetry are given. Other remarkable properties are also discussed.
DISCONTINUITIES AND COLLISION OF GRAVITATIONAL WAVES IN STRING THEORY
Authors: KEHAGIAS ALEXANDROS A. , PAPANTONOPOULOS E.
Published: November 2004

We examine here discontinuities in the metric, the antisymmetric tensor and the dilaton field which are allowed by conformal invariance. We find that the surfaces of discontinuity must necessarily be null and both shock and impulsive waves are allowed. We employ our results for the case of colliding plane gravitational waves and we discuss the SL(2, [Formula: see text]) × SU(2)/[Formula: see text] × [Formula: see text]WZW model in the present perspective. In particular, the singularities encountered in this model may be viewed as the result of the mutual focusing of the colliding waves.
CONSTRAINTS ON THE ELECTROWEAK UNIVERSAL PARAMETERS AND THE TOP AND HIGGS MASSES FROM UPDATED LEP/SLC DATA
Authors: MATSUMOTO SEIJI
Published: November 2004

A global analysis is performed using the recent data from LEP and SLC. Constraints on the electroweak universal parameters (S, T, U) and on the masses of the top quark and Higgs boson within the standard model (SM) are investigated. The uncertainties due to the QCD and QED effective couplings, αs(mz) and , [Formula: see text] are examined in detail. Even though the mean value of S is increased to be consistent with zero, the naive Technicolor models are still disfavored due to its reduced error. Within the SM, we find the 90% CL constraints; 133 GeV<mt<190 GeV and 10 GeV<mH< 440 GeV for αs(mz)=0.116 and [Formula: see text]. The experimental constraints on the ZbLbL vertex form factor, [Formula: see text] play an important role in disfavoring the region of large mt(mt~200GeV) and large mH(mH~1000 GeV). If mt is precisely known, the present electroweak data give a rather strict upper bound on the Higgs mass, mH<140(300) GeV at 95% CL, for mt=160(175) GeV and for the above αs(mz) and [Formula: see text].
QUANTUM OSCILLATOR AND A BOUND SYSTEM OF TWO DYONS
Authors: TER-ANTONYAN V.M. , NERSESSIAN A.
Published: November 2004

It is shown that U(1)-Hamiltonian reduction of a four-dimensional isotropic quantum oscillator results in a bound system of two spinless Schwinger’s dyons. Its wave functions and spectrum are constructed.
SUPERFIELD FORMULATION OF THE LAGRANGIAN BRST QUANTIZATION METHOD
Authors: LAVROV P.M. , MOSHIN P.YU. , RESHETNYAK A.A.
Published: November 2004

Lagrangian quantization rules for general gauge theories are proposed on a basis of a superfield formulation of the standard BRST symmetry. Independence of the S-matrix on a choice of the gauge is proved. The Ward identities in terms of superfields are derived.
TWO- AND THREE-DIMENSIONAL SPIN SYSTEMS WITH GONIHEDRIC ACTION
Authors: BATHAS G.K. , FLORATOS E. , SAVVIDY G.K. , SAVVIDY K.G.
Published: November 2004

We perform numerical simulations of the three-dimensional spin system with competing interaction that has been proposed in Refs. 1–3 as a model of random surfaces with gonihedric action. For the system with a self-intersection coupling constant k equal to one we observe the second-order phase transition at the temperature βc≃0.44. We suggest the full set of order parameters, which characterize the structure of the vacuum states and of the phase transition.
QUANTUM GROUP SUq(2) FOR COMPLEX q-DEFORMATION
Authors: JOHAL RAMANDEEP S. , GUPTA RAJ K.
Published: November 2004

q-deformed harmonic oscillator is established for any arbitrary complex q-deformation parameter (with real and imaginary q as its special cases) and the formalism so developed is used to construct the quantum group SUq(2). The eigenvalues of the Casimir of SUq(2) are now real, even for complex q-deformation (q=ea+ib). This happens for (a,b)≪1. Thus, the use of real part of energies in the earlier works of Gupta and collaborators7–14 is mathematically rigorous, since only small values of (a, b) are involved in all the nuclear and molecular physics problems studied7–14,18–20 so far.
REMARKS ON GRAVITATIONAL SOURCES
Authors: NG Y. JACK , DAM HENDRIK VAN
Published: November 2004

We show that, due to quantum fluctuations of the spacetime metric, any source of observable static gravitational fields is a classical object. We also show that, at the classical level, the gravitational mass of any system of finite volume is equal to its inertial mass in general only after time averaging.
INADEQUACY OF NARROW RESONANCE APPROXIMATION IN THE ϕ→γa0 AND ϕ→γf0 DECAYS
Authors: ACHASOV N.N. , GUBIN V.V.
Published: November 2004

It is shown that the approximation of the narrow widths of the f0 and a0 resonances, which is used in both theoretical and experimental investigations of the radiative decays ϕ→γa0 and ϕ→γf0, is not valid. We will explain that there is a need to take into account the corrections for finite widths.
HAMILTONIAN LATTICE GAUGE MODELS AND THE HEISENBERG DOUBLE
Authors: FROLOV S.A.
Published: November 2004

Hamiltonian lattice gauge models based on the assignment of the Heisenberg double of a Lie group to each link of the lattice are constructed in arbitrary spacetime dimensions. It is shown that the corresponding generalization of the gauge-invariant Wilson line observables requires to attach to each vertex of the line a vertex operator which goes to the unity in the continuum limit.
ON THE GENERALIZED TANH METHOD FOR THE (2+1)-DIMENSIONAL BREAKING SOLITON EQUATION
Authors: TIAN BO , GAO YI-TIAN
Published: November 2004

There is an open question as to whether or not the recently-proposed tanh method can be modified in order to proceed beyond the traveling or solitary wave solutions for nonlinear evolution equations. On the other hand, the class of the breaking soliton equations, which the self-dual Yang-Mills equation is found to belong to, is of current interest. In this letter, we propose a generalized tanh method, with symbolic computation, to construct a family of soliton-like solutions for a (2+1)-dimensional breaking soliton equation.
HIGGS BOSON MASSES IN NONMINIMAL SUPERSYMMETRY
Authors: ASATRIAN H.M. , EGUIAN G.K.
Published: November 2004

The Higgs boson mass problem is considered in the next-to-minimal supersymmetric standard model. The Higgs potential and the renormalization group equations for the gauge, Yukawa and scalar coupling constants are analyzed. The restrictions on the Higgs boson masses are found for the cases of presence and absence of spontaneous CP-violation.
SYMPLECTIC STRUCTURE OF LINEAR GRAVITY COUPLED TO A MASSIVE PARTICLE
Authors: KIM SUNG KU , SOH KWANG-SUP , YEE JAE HYUNG , HWANG DAE SUNG , NAMGUNG WUK
Published: November 2004

Jackiw-Teitelboim model of linear gravity coupled to a point particle is studied in a curved cylindrical spacetime. The classical solutions for the metric, the particle trajectory, and the scalar field are explicitly given. We studied the symplectic structure on the phase space of the classical solutions.
q-CALCULUS AND THE DISCRETE INVERSE SCATTERING
Authors: KARLO T. , JACOB H. , TRIPATHY K.C.
Published: November 2004

The discrete inverse scattering in one dimension has been re-identified with lattice calculus. By transforming the deformation parameter, the coordinate and the partial derivatives from lattice space to q-space, the Schrödinger equation with a potential is systematically analyzed. The potential having explicit q-dependence is derived from the knowledge of the spectral measure. The role of q to generate simulation is also highlighted.
EQUATION OF STATE AND TEMPERATURE OF MASSIVE NONRELATIVISTIC BOSONS ARISING IN THE UNIVERSE AT THE FIRST STAGE OF REHEATING
Authors: DYMNIKOVA I. , KRAWCZYK M.
Published: November 2004

We consider heavy nonrelativistic bosons with masses M~MGUT which arise in the Universe during phase transitions with spontaneous symmetry breaking at the grand unification scale. In the frame of statistical mechanics approach with model-independent description of cosmological background we show that the process of emerging of massive GUT bosons looks like evaporation of a Bose condensate. First massive nonrelativistic bosons behave like ideal quantum degenerate Bose gas which has the Gibbons-Hawking temperature due to the presence of the de Sitter event horizon.
EMERGENCE OF A PERIODIC PROFILE OF THE TIME SERIES OF POPULATION IN THE MINORITY GAME
Authors: HSIEH CHIA-LI , TSENG HSEN-CHE , CHEN HUNG-JUNG
Published: November 2004

Based on the results of existing studies of the minority game, we further explored the periodic properties of the time series of population and discovered its exhibition of a separate three-bump distribution, in which an unusual periodic pattern is existent. By defining "the variance of scores" of all the strategies, we found a method to identify the distinctive features between periodic and non-periodic distributions. We also found there exists a critical point at which periodic behavior disappears when N goes from large to small.
TEMPERATURE DEPENDENCE AND THE ROLE OF INTERNAL NOISE IN SIGNAL TRANSDUCTION EFFICIENCY OF CRAYFISH MECHANORECEPTORS
Authors: PANTAZELOU ELENI , DAMES CHRIS , MOSS FRANK , DOUGLASS JOHN , WILKENS LON
Published: November 2004

A simple phenomenon called stochastic resonance (SR), well known in nonlinear statistical physics, offers an explanation of how random fluctuations can enhance the detectability and/or the coherence of a weak signal in certain nonlinear dynamical systems. It is interesting to speculate that SR may play a role in the remarkable sensitivity exhibited by numerous biological sensory systems: systems which are themselves often inherently noisy and which, moreover, must usually operate in a noisy environment. A distinction is thus drawn between the external, or environmental, noise and the internal noise inherent in the sensory neurons themselves and distinguished by the randomness in time intervals between action potential spikes. We report the results of experiments with the internal noise, the intensity of which is varied by controlling the temperature of the preparation during the experiment. The useful range of temperatures could be extended by acclimating individual crayfish to a low or high temperature environment for many weeks prior to the experiment. Our results indicate that noise plays a significant role in signal transduction efficiency, increasing the signal-to-noise (SNR) ratio exponentially with noise intensity up to a maximum. Increasing the temperature beyond this maximum results in reduced SNRs and sharply reduced internal noise levels. The results of shifts in the data due to acclimation temperature can be removed by plotting the data versus the noise level, indicating that the noise may be a universal quantity in the dynamics of biological neurons.
NEW METHOD FOR STABILIZATION OF UNSTABLE PERIODIC ORBITS IN CHAOTIC SYSTEMS
Authors: GALIAS ZBIGNIEW
Published: November 2004

In this paper we present a new method of controlling periodic orbits in chaotic systems. This method can be applied in situations when the chaotic system depends on one system parameter, which can be changed over a continuous interval or over a discrete, two-element set. We compare the new method to other ones, discuss its properties, and illustrate our approach with a numerical example.
REDUCTION ENTROPY
Authors: TAKENS FLORIS
Published: November 2004

In this paper we study the numerical determination of the different reduction entropies (or α-entropies) of dynamical systems from time series. This method is advocated as a more suitable way to investigate the different aspects of sensitive dependence on initial positions than the determination of Lyapunov exponents, especially in the case of “noisy” time series.
BURSTING, SPIKING, CHAOS, FRACTALS, AND UNIVERSALITY IN BIOLOGICAL RHYTHMS
Authors: CHAY TERESA REE , FAN YIN SHUI , LEE YOUNG SEEK
Published: November 2004

Biological systems offer many interesting examples of oscillations, chaos, and bifurcations. Oscillations in biology arise because most cellular processes contain feedbacks that are appropriate for generating rhythms. These rhythms are essential for regulating cellular function. In this tutorial review, we treat two interesting nonlinear dynamic processes in biology that give rise to bursting, spiking, chaos, and fractals: endogenous electrical activity of excitable cells and Ca2+ releases from the Ca2+ stores in nonexcitable cells induced by hormones and neurotransmitters. We will first show that each of these complex processes can be described by a simple, yet elegant, mathematical model. We then show how to utilize bifurcation analyses to gain a deeper insight into the mechanisms involved in the neuronal and cellular oscillations. With the bifurcating diagrams, we explain how spiking can be transformed to bursting via a complex type of dynamic structure when the key parameter in the model varies. Understanding how this parameter would affect the bifurcation structure is important in predicting and controlling abnormal biological rhythms. Although we describe two very different dynamic processes in biological rhythms, we will show that there is universality in their bifurcation structures.
PARAMETRICALLY EXCITED NONLINEAR TWO-DEGREE-OF-FREEDOM SYSTEMS WITH NONSEMISIMPLE ONE-TO-ONE RESONANCE
Authors: CHIN C. , NAYFEH A.H.
Published: November 2004

The response of a parametrically excited two-degree-of-freedom system with quadratic and cubic nonlinearities and a nonsemisimple one-to-one internal resonance is investigated. The method of multiple scales is used to derive four first-order differential equations governing the modulation of the amplitudes and phases of the two modes for the cases of fundamental and principal parametric resonances. Bifurcation analysis of the case of fundamental parametric resonance reveals that the quadratic nonlinearities qualitatively change the response of the system. They change the pitchfork bifurcation to a transcritical bifurcation. Cyclic-fold, Hopf bifurcations of the nontrivial constant solutions, and period-doubling sequences leading to chaos are induced by these quadratic terms. The effects of quadratic nonlinearities for the case of principal parametric resonance are discussed.
ELECTRIC FIELD INFLUENCE ON TRAVELING WAVE PROPAGATION AND STATIONARY PATTERN FORMATION
Authors: MOSQUERA J. , GÓMEZ-GESTEIRA M. , PÉREZ-MUÑUZURI V. , MUÑUZURI A.P. , PÉREZ-VILLAR V.
Published: November 2004

The electric field influence on pattern formation and traveling wave propagation is investigated in the framework of the Oregonator model. When an electric field is applied to a system that can suffer spatial instabilities, Turing and Turing-like patterns (traveling fronts that become stationary patterns when reaching a zero-flux boundary) are observed. On the other hand, when an electric field is applied to a system that cannot become unstable by spatial terms and where wavefronts are propagating in the absence of electric fields, the velocity of these wavefronts is modified and can even be reversed. This is in good agreement with previous experimental results.
A SPECTRAL APPROACH FOR CHAOS PREDICTION IN DELAYED CELLULAR NEURAL NETWORKS
Authors: GILLI MARCO
Published: November 2004

We apply a spectral technique for predicting chaos in a complex system, described by a functional differential equation: a delayed cellular neural network. We show that by solving simple sets of transcendental equations, the delay which gives rise to period doubling bifurcation and the range of parameters for which chaos occurs can be predicted with a very high accuracy.
ESTIMATION OF SYMMETRY BREAKING AND ESCAPE BY OBSERVATION OF MANIFOLD TANGENCIES
Authors: CLIFFORD M.J. , BISHOP S.R.
Published: November 2004

A heteroclinic tangency marking the initial change in secondary Birkhoff signature is identified as a good indicator of the chaotic escape from a symmetric potential well under parametric excitation as it occurs shortly after the symmetry breaking bifurcation which precedes the final event. This is compared to the criterion for asymmetric potential wells, and the lack of any change in primary Birkhoff signature highlights the differences in the two cases.
FOURIER ANALYSIS OF THE COMPLEX MOTION OF SPIRAL TIPS IN EXCITABLE MEDIA
Authors: PLESSER THEO , MÜLLER KARL-HEINZ
Published: November 2004

An analysis of spiral tip trajectories by complex Fast Fourier Transform (FFT) is presented. The trajectories are obtained from the numerical integration of partial differential equations describing the Oregonator model of an excitable medium. Their analysis shows: (1) There are regions in the (ε, f) parameter space of the model where for a given ε and increasing f up to four frequency branches appear. The frequencies of these branches determine the coarse structure and geometry of the pattern, i.e., the number and the size of their loops, and are called "structural" frequencies. Other frequencies of the spectra are related with the detailed shape of the loops. (2) The interplay of up to four structural frequencies generates regular trajectories of high complexity but no sign of chaos has been found. (3) The spiral wave outside the core region is independent of the complexity of the tip trajectory. It is solely determined by the structural Fourier component with frequency ν and amplitude r that has the highest circular speed c = 2πrν.
GLOBAL ANALYSIS OF DYNAMICAL SYSTEMS USING POSETS AND DIGRAPHS
Authors: HSU C. S.
Published: November 2004

In this paper the resources of the theory of partially ordered sets (posets) and the theory of digraphs are used to aid the task of global analysis of nonlinear dynamical systems. The basic idea underpinning this approach is the primitive notion that a dynamical systems is simply an ordering machine which assigns fore-and-after relations for pairs of states. In order to make the linkage between the theory of posets and digraphs and dynamical systems, cell mapping is used to put dynamical systems in their discretized form and an essential concept of self-cycling sets is used. After a discussion of the basic notion of ordering, appropriate results from the theory of posets and digraphs are adapted for the purpose of determining the global evolution properties of dynamical systems. In terms of posets, evolution processes and strange attractors can be studied in a new light. It is believed that this approach offers us a new way to examine the multifaceted complex behavior of nonlinear systems. Computation algorithms are also discussed and an example of application is included.
ADAPTIVE ORBIT CORRECTION IN CHAOS CONTROL
Authors: DOERNER R. , HÜBINGER B. , MARTIENSSEN W.
Published: November 2004

The deterministic chaotic motion of a nonlinear system is governed by the set of unstable periodic orbits constituting the strange attractor. We introduce an adaptation scheme to improve experimentally the coordinates of orbits calculated from an approximate model or extracted from a time series. The method also allows to trace an unstable orbit if the system parameters are slowly changing. Feasibility of the method is demonstrated by numerical simulation at the Hénon system using the OGY control method, and experimentally at a driven pendulum using the local control method.
CONSTRUCTING INVARIANT MEASURES FROM DATA
Authors: FROYLAND GARY , JUDD KEVIN , MEES ALISTAIR I. , WATSON DAVID , MURAO KENJI
Published: November 2004

We present a method of approximating an invariant measure of a dynamical system from a finite set of experimental data. Our reconstruction technique automatically provides us with a partition of phase space, and we assign each set in the partition a certain weight. By refining the partition, we may make our approximation to an invariant measure of the reconstructed system as accurate as we wish. Our method provides us with both a singular and an absolutely continuous approximation, so that the most suitable representation may be chosen for a particular problem.
ON THE MATHEMATICAL MODELLING OF INTRONIC SECTORS OF THE DNA MOLECULE
Authors: MANSILLA RICARDO , MATEO-REIG ROSENDO
Published: November 2004

Based on thermodynamic features present in intronic regions of eukaryotics DNA, a fitness function for those regions is built and used as selective criterion for a genetic-algorithm based evolutionary model. Extensive computer simulations show that the proposed model reproduces long-range correlations as observed in real intronic sequences reported in the literature.
SIMPLE AND COMPLEX DYNAMICS FOR ONE-DIMENSIONAL MANIFOLD MAPS
Authors: FEDORENKO VLADIMIR
Published: November 2004

We give a characterization of complex and simple interval maps and circle maps (in the sense of positive or zero topological entropy respectively), formulated in terms of the description of the dynamics of the map on its chain recurrent set. We also describe the behavior of complex maps on their periodic points.
ON THE EXTENSION OF SHARKOVSKIĬ'S THEOREM TO CONNECTED GRAPHS WITH NON-POSITIVE EULER CHARACTERISTIC
Authors: LLIBRE J. , PARAÑOS J. , RODRIGUEZ J. A.
Published: November 2004

This paper contains a characterization of all possible sets of periods for all continuous self-maps on a connected topological graph with zero Euler characteristic having all branching points fixed. A characterization in terms of linear orderings is given for the simplest connected topological graph with zero Euler characteristic that has a branching point, the topological graph shaped like the letter σ. In this case a proof follows by lifting the continuous self-map on σ. We show the difficulties that arise in the simplest connected topological graphs with negative Euler characteristic, like for instance the topological graph shaped like the figure 8.
SELF-STRUCTURING AND SELF-SIMILARITY IN BOUNDARY VALUE PROBLEMS
Authors: Yu. ROMANENKO E. , SHARKOVSKY A. N. , VEREIKINA M. B.
Published: November 2004

This paper aims at understanding the mathematical features of self-structuring in distributive media. We suggest a mathematical formalism for the description of structures and their dynamics in time and in space; in particular, the notions of coherent and self-similar structures are covered. A specific class of nonlinear boundary value problems presenting the evolution of some ideal medium is studied. Some regularities of structures appearing in its solutions with time increasing are established, The mathematical formulation is accompanied by computer pictures which visualize various properties of structures, in particular, the cascade process of appearance of coherent spatial-temporal structures and the process of forming spatially self-similar structures which become fractal as t → ∞.