bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE CREATION OF DENSITY FLUCTUATIONS FROM THE HETEROTIC COSMIC SUPERSTRING
Authors: POLLOCK M. D.
Published: November 2004

It has been proved by Witten that the heterotic superstring theory appears phenomeno-logically as a closed, superconducting, axionic cosmic string attached to one axion domain wall. After reduction from ten dimensions to four dimensions, the effective mass per unit length of the string is [Formula: see text], where α′ = 1/2πμ is the Regge slope parameter and bc is the compactification length. The string-wall system is present ab initio in the expanding Friedmann universe, and is dominated energetically by the string. Consequently, a scale-free spectrum of density (metric) fluctuations is impressed upon the space-time at its classical inception, whose magnitude, according to Zel'dovich, is ξ ≡ δρ/ρ ≈ 4πGμc ≈ 4 × 10−2g2, where [Formula: see text] is the Newton gravitational constant, M P is the Planck mass and g is the string gauge coupling parameter. The string disappears via gravitational or electromagnetic radiation on the time scale τ ≲ 2M P /μc, thus removing all conflict with the non-observation of timing residuals in the millisecond pulsars. The value of ξ should be commensurate with that previously obtained from the effective action, illustrating the notion of reciprocity between the two-dimensional, world-sheet and four-dimensional, space-time formulations of the theory. It therefore suggests that bc ≈ b H ≡ 1/2πT H , where [Formula: see text] is the Hagedorn temperature, since the two-loop calculation of the free energy by Hellmund and Kripfganz indicates that g2 → 0 as T → T H .
THE EIGENVECTORS OF q-DEFORMED CREATION OPERATOR $a_q^+$ AND THEIR PROPERTIES
Authors: JU GUOXIN , TAO JINHE , LIU ZIXIN , WANG MIAN
Published: November 2004

The eigenvectors of q-deformed creation operator [Formula: see text] are discussed for q being real or a root of unity by using the contour integral representation of δ function. The properties for the eigenvectors are also discussed. In the case of qp = 1, the eigenvectors may be normalizable.
ON THE SCHWINGER–DYSON EQUATIONS FOR A VERTEX MODEL COUPLED TO 2-D GRAVITY
Authors: KAVALOV AL.
Published: November 2004

We consider a two-matrix model with the interaction involving the term tr ABAB, which is quartic in angular variables. It describes a vertex model (in particular — of F-model type) on the lattice of fluctuating geometry and is the simplest representative of the class of matrix models describing coupling to two-dimensional gravity of general vertex models. This class includes most of the physically interesting matrix models, such as lattice gauge theories and matrix models describing extrinsic curvature strings. We show that the system of loop (Schwinger–Dyson) equations of the model decouples in the planar limit and allows one to find closed equations for arbitrary correlators, including the ones involving angular variables. We write down the equations for the two-point function and the eigenvalue density and sketch the calculation of perturbative corrections to the free case
ON THE DYNAMICAL EQUATION OF A SPHERICAL RADIATING SHELL AND THE OSCILLATING STARS
Authors: AQUILANO ROBERTO O. , CASTAGNINO MARIO A. , LARA LUIS P. , CERVILLERA LUIS P. NEIRA
Published: November 2004

A classical and post-Newtonian model of pulsating star is studied.

The condition for an oscillating behavior and the corresponding period are computed.
GENERAL BRANCHING FUNCTIONS OF AFFINE LIE ALGEBRAS
Authors: HWANG STEPHEN , RHEDIN HENRIC
Published: November 2004

Explicit expressions are presented for general branching functions for cosets of affine Lie algebras ĝ with respect to subalgebras ĝ′ for the cases where the corresponding finite-dimensional algebras g and g′ are such that g is simple and g′ is either simple or sums of u(1) terms. A special case of the latter yields the string functions. Our derivation is purely algebraical and has its origin in the results on the BRST cohomology presented by us earlier. We will here give an independent and simple proof of the validity of our results. The method presented here generalizes in a straightforward way to more complicated g and g′ such as sums of simple and u(1) terms.
RENORMALIZATION IN TRUNCATED PARISI-SOURLAS MODEL
Authors: CHUNG MYUNG-HOON
Published: November 2004

The Parisi-Sourlas model is truncated by ignoring irrelevant terms and introducing an N-vector field. The β-functions for the model of 4−ε dimensions are calculated up to two-loop order in the dimensional regularization scheme. By using the β-functions, the critical exponents are evaluated up to ε2-order. The critical exponents of the truncated Parisi-Sourlas model are compared with those of the ordinary N-vector model. It is found that this model roughly corresponds to the (N−2)-vector model. In fact, the ghost-like fields contribute to the critical exponents in the opposite way, being contrasted with the ordinary N-vector field.
PARTICLE CONJUGATION AND THE 1/Nc CORRECTIONS TO gA
Authors: SCHECHTER J. , WEIGEL H.
Published: November 2004

We impose the requirement that the isovector axial vector current for the soliton sector of the chiral quark model transforms correctly under particle conjugation. This forces us to choose an otherwise arbitrary ordering of collective space operators in such a way that the next-to-leading 1/Nc correction to gA computed in the usual cranking model vanishes.
SUPERSYMMETRIC THEORIES ON A NONSIMPLY CONNECTED SPACETIME
Authors: DAS ASHOK , HOTT MARCELO
Published: November 2004

We study the Wess-Zumino theory on ℝ3×S1 where a spatial coordinate is compactified. We show that when the bosonic and fermionic fields satisfy the same boundary condition, the theory does not develop a vacuum energy or tadpoles. We work out the two-point functions at one-loop and show that their forms are consistent with the nonrenormalization theorem. However, the two-point functions are nonanalytic and we discuss the structure of this nonanalyticity.
BV QUANTIZATION OF A VECTOR-TENSOR GAUGE THEORY WITH TOPOLOGICAL COUPLING
Authors: AMORIM R. , BARCELOS-NETO J.
Published: November 2004

We use the BV quantization method for a theory with coupled tensor and vector gauge fields through a topological term. We consider in detail the reducibility of the tensorial sector as well as the appearance of a mass term in the effective vectorial theory.
ALGEBRAIC SOLUTIONS OF YANG-MILLS-HIGGS EQUATIONS
Authors: BRIHAYE Y. , GILLER STEFAN , KOSINSKI PIOTR
Published: November 2004

We study the SU(2) Yang-Mills-Higgs equations with the Higgs field in an arbitrary irreducible representation of the gauge group. We propose an ansatz for the classical fields which, solving the classical equations, leads to systems of coupled differential equations. Several regular solutions of these systems can be constructed explicitly; they are spatially homogeneous and periodic in time. The connection between our solutions and a recent numerical analysis of sphaleron (monopole)’s evolution is discussed.
A COHERENT STATE PATH INTEGRAL FOR ANYONS
Authors: GRUNDBERG J. , HANSSON T.H.
Published: November 2004

We derive an su (1, 1) coherent state path integral formula for a system of two one-dimensional anyons in a harmonic potential. By a change of variables we transform this integral into a coherent states path integral for a harmonic oscillator with a shifted energy. The shift is the same as the one obtained for anyons by other methods. We justify the procedure by showing that the change of variables corresponds to an su (1, 1) version of the Holstein-Primakoff transformation.
NEUTRINO ENERGY EIGENSTATES IN MATTER WITH VARYING DENSITY
Authors: LEE JAE SIK , KIM JAE KWAN
Published: November 2004

We consider the energy eigenstates of neutrino in matter with varying density. From this consideration we calculate the transition probability of P(νe→νe) as a function of ratio of neutrino energy to neutrino mass difference squared [Formula: see text] in solar neutrino case. We show that our results are consistent with those results obtained by considering the effective mass eigenstates and level crossing.
LORENTZ COVARIANCE AS A SOURCE OF SOLITON DEFLATION IN QUANTUM FIELD THEORY
Authors: SVESHNIKOV K.
Published: November 2004

It is shown that extended particle-like solutions should collapse infinitely into some discontinuous configurations of the same topology, but with vanishing mass. Analytic results concerning the general properties and asymptotic rates of such a process are given for (1+1)-dimensional soliton models.
COMPLEX-TIME APPROACH FOR SEMICLASSICAL QUANTUM TUNNELING
Authors: AOYAMA HIDEAKI , HARANO TOSHIYUKI
Published: November 2004

The complex-time method for quantum tunneling is studied. In one-dimensional quantum mechanics, we construct a reduction formula for a Green function in the number of turning points based on the WKB approximation. This formula yields a series, which can be interpreted as a sum over the complex-time paths. The weights of the paths are determined.
PHASE STRUCTURES OF THE (2+1)-DIMENSIONAL INFINITE-NCPN−1 MODEL WITH TWISTED BOUNDARY CONDITIONS
Authors: HONG SEOK-IN
Published: November 2004

We investigate the finite-temperature Néel transitions of the (2+1)-dimensional infinite-NCPN−1 model with a finite spatial dimension. We consider all possible boundary conditions containing the twisted (antiperiodic) one for the imaginary time (inverse temperature) and one finite space: periodic-antiperiodic, antiperiodic-periodic, and antiperiodic-antiperiodic. Simple analytic expressions for the long-range Néel order (LRNO) and the critical line are obtained. Phase diagrams have a region where LRNO appears. Our system can have LRNO even in the infinite-size limit if the imaginary-time axis has the antiperiodic boundary condition.
KAON Δ = ½ RULE, KL—KS MASS DIFFERENCE AND OLD-FASHIONED PERTURBATION THEORY
Authors: SCADRON M.D. , ELIAS V.
Published: November 2004

We construct a very short-distance weak interaction Δ = ½ Hamiltonian and use it in an old-fashioned perturbation theory to explain both first-order weak [Formula: see text] and [Formula: see text] decays and the second-order weak KL—KS mass difference.
STRANGENESS PARAMETERS OF THE PROTON
Authors: SCHRAMM STEFAN
Published: November 2004

The strange magnetic and electric moments of the proton are calculated. The proton is described in the framework of the constituent quark model. The form factors of the constituent quarks are derived using the NJL model of quarks and the numerical results are discussed in context with parity-violating electron scattering experiments.
CAN THE PHOTON QUADRATIC DIVERGENCE BE CANCELED NUMERICALLY?
Authors: BLOCH J.C.R. , PENNINGTON M.R.
Published: November 2004

The behavior of the photon renormalization function in strong coupling QED has been recently studied numerically by Kondo, Mino and Nakatani. We find that the sharp decrease in its behavior at intermediate photon momenta is an artefact of the method used to remove the quadratic divergence in the vacuum polarization. We discuss how this can be avoided in numerical studies of the Schwinger-Dyson equations.
ASYMPTOTIC EXPANSIONS IN MOMENTA AND MASSES AND CALCULATION OF FEYNMAN DIAGRAMS
Authors: SMIRNOV V.A.
Published: November 2004

General results on asymptotic expansions of Feynman diagrams in momenta and/or masses are reviewed. It is shown how they are applied for calculation of massive diagrams.
A COMPARISON OF THE PROPER-TIME EQUATION AND THE RENORMALIZATION GROUP β-FUNCTION IN STRING THEORY
Authors: SATHIAPALAN B.
Published: November 2004

It is known that there is a proportionality factor relating the β-function and the equations of motion viz. the Zamolodchikov metric. Usually this factor has to be obtained by other methods. The proper-time equation, on the other hand, is the full equation of motion. We explain the reasons for this and illustrate it by calculating corrections to Maxwell’s equation. The corrections are calculated to cubic order in the field strength, but are exact to all orders in derivatives. We also test the gauge covariance of the proper-time method by calculating higher (covariant) derivative corrections to the Yang-Mills equation.
BROKEN SU(8) AND HADRONIC MASS RELATIONS IN HEAVY QUARK EFFECTIVE THEORY
Authors: DE CAMARGO A. FERRAZ , FERREIRA P. LEAL , PALLADINO B.E.
Published: November 2004

Mass relations for hadrons containing a single heavy quark (charm or beauty) are studied from the viewpoint of a quark model with broken SU(8) symmetry, developed by Hendry and Lichtenberg some time ago, in comparison to that of the heavy quark effective theory. The interplay of the two approaches is explored and spectroscopic consequences derived.
REPRESENTATIONS OF COMPOSITE BRAIDS AND INVARIANTS FOR MUTANT KNOTS AND LINKS IN CHERN-SIMONS FIELD THEORIES
Authors: RAMADEVI P. , GOVINDARAJAN T.R. , KAUL R.K.
Published: November 2004

We show that any of the new knot invariants obtained from Chern-Simons theory based on an arbitrary non-Abelian gauge group do not distinguish isotopically inequivalent mutant knots and links. In an attempt to distinguish these knots and links, we study Murakami (symmetrized version) r-strand composite braids. Salient features of the theory of such composite braids are presented. Representations of generators for these braids are obtained by exploiting properties of Hilbert spaces associated with the correlators of Wess-Zumino conformal field theories. The r-composite invariants for the knots are given by the sum of elementary Chern-Simons invariants associated with the irreducible representations in the product of r representations (allowed by the fusion rules of the corresponding Wess-Zumino conformal field theory) placed on r individual strands of the composite braid. On the other hand, composite invariants for links are given by a weighted sum of elementary multicolored Chern-Simons invariants. Some mutant links can be distinguished through the composite invariants, but mutant knots do not share this property. The results, though developed in detail within the framework of SU(2) Chern-Simons theory are valid for any other non-Abelian gauge groups.
A STRING SCENARIO FOR INFLATIONARY COSMOLOGY
Authors: ELLIS JOHN , NANOPOULOS D.V. , MAVROMATOS N.E.
Published: November 2004

We describe a scenario for inflation in the framework of noncritical string theory, which does not employ an inflaton field. There is an exponential expansion of the volume of the Universe, induced by enormous entropy production in the early stages of cosmological evolution. This is associated with the loss of information carried by global string modes that cross the particle horizon. It is the same loss of information that induces irreversible time flow when target time is identified with the worldsheet Liouville mode. The resulting scenario for inflation is described by a string analog of the Fokker-Planck equation that incorporates diffusion and dissipative effects. Cosmological density perturbations are naturally small.
D- AND τ-DECAYS: PLACING NEW BOUNDS ON R-PARITY-VIOLATING SUPERSYMMETRIC COUPLINGS
Authors: BHATTACHARYYA GAUTAM , CHOUDHURY DEBAJYOTI
Published: November 2004

D- and τ-decays are used to place bounds on some R-parity-violating λ′-type Yukawa interactions. Some of these bounds are competitive with the existing ones, some are improved while some are new.
FLUCTUATIONS OF THE UNRUH TEMPERATURE
Authors: DEMERS JEAN-GUY
Published: November 2004

Using the influence functional formalism, the problem of an accelerating detector in the presence of a scalar field in its ground state is considered in Minkowski space. As is known since the work of Unruh, to a quantum-mechanical detector following a definite, classical acceleration, the field appears to be thermally excited. We relax the requirement of perfect classicality for the trajectory and substitute it with one of derived classicality through the criteria of decoherence. The ensuing fluctuations in temperature are then related with the time and the amplitude of excitation in the detector’s internal degree of freedom.
LIE ALGEBRAIC DISCRETIZATION OF DIFFERENTIAL EQUATIONS
Authors: SMIRNOV YURI , TURBINER ALEXANDER
Published: November 2004

A certain representation for the Heisenberg algebra in finite difference operators is established. The Lie algebraic procedure of discretization of differential equations with isospectral property is proposed. Using sl 2-algebra based approach, (quasi)-exactly-solvable finite difference equations are described. It is shown that the operators having the Hahn, Charlier and Meissner polynomials as the eigenfunctions are reproduced in the present approach as some particular cases. A discrete version of the classical orthogonal polynomials (like Hermite, Laguerre, Legendre and Jacobi ones) is introduced.
COMMENT ON THE RENORMALIZATION GROUP IMPROVEMENT IN EXCLUSIVE b→c TRANSITIONS
Authors: URALTSEV N.G.
Published: November 2004

We argue, using rather general considerations, that the corrections to the exact one-loop expressions for the perturbative factors ηA, ηV in the exclusive zero recoil semileptonic transitions, inferred from the existing next-to-leading logarithmic summations of terms log mb/mc, are numerically irrelevant for actual values of mc and mb. Adopting these corrections for the values of the form factors is misleading. Likewise one cannot estimate their theoretical uncertainty in this way. The central theoretical value for ηA if taken literally is then ηA≃0.965.
LOCAL GAUGE INVARIANCE OF RELATIVISTIC QUANTUM MECHANICS AND CLASSICAL RELATIVISTIC FIELDS
Authors: DASTIDAR T.K. RAI , DASTIDAR KRISHNA RAI
Published: November 2004

We extend our earlier work1 to demonstrate that all free matter fields (Bose as well as Fermi, massive as well as massless), that transform like Φ→TΦ under a local Abelian gauge transformation T= exp (–iβ) with β an arbitrary function of space and time, are governed by field equations that are invariant under such local gauge transformations.
INTEGRABLE SYSTEMS ON FLAG MANIFOLD AND COHERENT STATE PATH-INTEGRAL
Authors: KIM MYUNG-HO , OH PHILLIAL
Published: November 2004

We construct integrable models on flag manifold by using the symplectic structure explicitly given in the Bruhat coordinatization of flag manifold. They are noncommutative integrable and some of the conserved quantities are given by the Casimir invariants. We quantize the systems using the coherent state path-integral technique and find the exact expression for the propagator for some special cases.
A COSMOLOGY WITH A TIME AND SPACE COORDINATE-DEPENDENT SCALE FACTOR
Authors: KIM C.W. , SINIBALDI A. , SONG J.
Published: November 2004

Based on the increase of Ω0 as a function of cosmic scale, the Robertson-Walker metric and the Einstein equation are generalized so that Ω0, H0 and the age of the Universe, to, all become functions of cosmic scales at which we observe them. The calculated local (within our galaxy) age of the Universe is about 18 Gyr, consistent with the ages of the oldest stars and globular clusters in our galaxy, while the ages at distant scales are shorter than the local age, solving the age puzzle. It is also shown that H0 becomes scale-dependent.
THE CANONICAL q-TRANSFORMATIONS WITH TWO q-PARA-BOSE OSCILLATORS
Authors: BANG HA HUY
Published: November 2004

The canonical q-transformations with two q-para-Bose oscillators are described. It turns out that the two q-oscillators are not exactly independent.
QUANTUM COSMOLOGY AND THE VALUE OF Λ
Authors: COULE D.H.
Published: November 2004

We analyze a simple quantum cosmological model with just a Λ term present. Different results for the expected value of Λ are obtained depending on the boundary conditions applied. In the Euclidean regime the Hartle-Hawking boundary condition gives the factor exp (1/Λ) but, in agreement with Rubakov et al.,10 is badly behaved for negative Λ. Tunneling boundary conditions suggest an initially large value for Λ.

If only Lorentzian regions are considered, all boundary conditions suggest an initially large value of A for spatial curvature k=1. This differs from the previously obtained results of Strominger11 for such models, who implicitly assumed that the universe has occurred in its present (large size) form by a quantum event. Whereas, quantum behavior should be restricted to epochs when the universe was ~ Planck size.
DILATONIC GRAVITY NEAR TWO DIMENSIONS AS A STRING THEORY
Authors: ELIZALDE E. , ODINTSOV S.D.
Published: November 2004

Using the renormalization group formalism, a sigma model of a special type — in which the metric and the dilaton depend explicitly on one of the string coordinates only — is investigated near two dimensions. It is seen that dilatonic gravity coupled to N scalar fields can be expressed in this form, using a string parametrization, and that it possesses the usual uv fixed point. However, in this stringy parametrization of the theory the fixed point for the scalar-dilaton coupling turns out to be trivial, while that for the gravitational coupling remains the same as in previous studies being, in particular, nontrivial.
CHARGE RADII OF HYPERONS
Authors: SAHU SARIRA
Published: November 2004

The momentum projected SU(3) chiral color dielectric model (CCDM) is employed to calculate the charge root mean square radii and charge distribution of hyperons. The gluonic and pionic contributions are treated perturbatively. We compare our result with that of Skyrme, MIT bag and cloudy bag model. The charge distribution of Λ in CCDM is similar to that of Skyrme model prediction.
ON GAUGE-INVARIANT BOUNDARY CONDITIONS FOR 2-D GRAVITY WITH DYNAMICAL TORSION
Authors: VASSILEVICH DMITRI V.
Published: November 2004

In the example of R2+T2 gravity on the unit two-dimensional disk we demonstrate that in the presence of an independent spin connection it is possible to define local gauge-invariant boundary conditions even on boundaries which are not totally geodesic. One-loop partition function and the corresponding heat kernel are calculated.
A LIGHT TOP-SQUARK AND ITS CONSEQUENCES AT HIGH ENERGY COLLIDERS
Authors: LOPEZ JORGE L. , NANOPOULOS D.V. , ZICHICHI A.
Published: November 2004

An interesting prediction of a string-inspired one-parameter SU (5)× U (1) supergravity model, is the fact that the lightest member [Formula: see text] of the top-squark doublet [Formula: see text], may be substantially lighter than the top quark. This sparticle [Formula: see text] may be readily pair-produced at the Tevatron and, if [Formula: see text] even be observed at the end of Run IB. Top-squark production may also be a source of top-quark-like signatures in the dilepton and ℓ+ jets channels, if the experimental acceptances are tuned to look for soft leptons. Such a light top-squark is linked with a light supersymmetric spectrum, which can certainly be searched for at the Tevatron through trilepton and squark-gluino searches, and at LEPII through direct [Formula: see text] pair-production and via chargino and Higgs-boson searches.
MODULI SPACES IN THE FOUR-DIMENSIONAL TOPOLOGICAL HALF-FLAT GRAVITY
Authors: ABE MITSUKO
Published: November 2004

We classify the moduli spaces of the four-dimensional topological half-flat gravity models by using the canonical bundle. For a K3-surface or T4, they describe an equivalent class of a trio of the Einstein-Kähler forms (the hyperkähler forms). We calculate the dimensions of these moduli spaces by using the Atiyah-Singer Index theorem. We mention the partition function and the possibility of the observables in the Witten-type topological half-flat gravity model case.
STRING QUANTIZATION IN CURVED SPACETIMES: NULL STRING APPROACH
Authors: DE VEGA H.J. , GIANNAKIS I. , NICOLAIDIS A.
Published: November 2004

We study quantum strings in strong gravitational fields. The relevant small parameter is [Formula: see text] where Rc is the curvature of the spacetime and T0 is the string tension. Within our systematic expansion we obtain to zeroth-order the null string (string with zero tension), while the first-order correction incorporates the string dynamics. We apply our formalism to quantum null strings in de Sitter spacetime. After a reparametrization of the worldsheet coordinates, the equations of motion are simplified. The quantum algebra generated by the constraints is considered, ordering the momentum operators to the right of the coordinate operators. No critical dimension appears. It is anticipated, however, that the conformal anomaly will appear when the first-order corrections proportional to T0, are introduced.
TIME DELAY IN SEMICLASSICAL SCATTERING THEORY
Authors: PATO M.P. , HUSSEIN M.S.
Published: November 2004

An asymptotic evaluation of the time delay in the context of the semiclassical approximation is performed. It is shown that it is related to Stokes’s discontinuities of the asymptotic series caused by singularities determined by the turning points and points of equilibrium of the effective potential in the complex r-plane. The theory is applied to the repulsive potentials inversely proportional to the fourth and the sixth power of the distance. The case of complex potentials, usually considered in nuclear scattering is also discussed.
Q-DEFORMED OSCILLATOR ALGEBRA AND AN INDEX THEOREM FOR THE PHOTON PHASE OPERATOR
Authors: FUJIKAWA KAZUO , KWEK L.C. , OH C.H.
Published: November 2004

The quantum deformation of the oscillator algebra and its implications on the phase operator are studied from a viewpoint of an index theorem by using an explicit matrix representation. For a positive deformation parameter q or q=exp(2πiθ) with an irrational θ, one obtains an index condition dim ker a–dim ker a†=1 which allows only a nonhermitian phase operator with dim ker eiφ–dim ker(eiφ)†=1. For q=exp(2πiθ) with a rational θ, one formally obtains the singular situation dim ker a=∞ and dim ker a†=∞, which allows a hermitian phase operator with dim ker eiΦ–dim ker(eiΦ)†=0 as well as the nonhermitian one with dim ker eiφ– dim ker(eiφ)†=1. Implications of this interpretation of the quantum deformation are discussed. We also show how to overcome the problem of negative norm for q=exp(2πiθ).
UNIVERSALITY OF THE VACUA OF THE STOCHASTIC STABILIZED 2-D QUANTUM GRAVITY
Authors: DIEGO OSCAR
Published: November 2004

In this letter we study the universality of the nonperturbative effects and the vacua structure of the stochastic stabilization of the matrix models which defines pure 2-D quantum gravity.
THE CLASSICAL BASIS FOR κ-DEFORMED POINCARÉ ALGEBRA AND SUPERALGEBRA
Authors: KOSIŃSKI P. , LUKIERSKI J. , SOBCZYK J. , MAŚLANKA P.
Published: November 2004

We describe here the general solution describing generators of κ-deformed Poincaré algebra as the functions of classical Poincaré algebra generators as well as the inverse formulas. Further we present analogous relations for the generators of N=1, D=4 κ-deformed Poincaré superalgebra expressed by the classical Poincaré superalgebra generators. In such a way we obtain the κ-deformed Poincaré (super)algebras with all the quantum deformation present only in the co-algebra sector. As an application we use the classical basis of κ-deformed Poincaré superalgebra for obtaining a new result: the κ-deformation of supersymmetric spin (Pauli-Lubanski) Casimir.
IMPORTANCE OF THE π-FIELD IN THE RELATIVISTIC MEAN FIELD THEORY FOR NUCLEAR MATTER
Authors: ZHANG QI-REN , GREINER WALTER
Published: November 2004

We generalize the Walecka model for nuclear matter by including the π-field. It is found that a finite mean π-field may lower the energy per nucleon even in the nuclear matter of subnormal density. A mean π-field may significantly change the nuclear equation of state. The importance of considering the π-field in the relativistic mean field theory for nuclear matter is therefore emphasized.
GAMMA RAY BURSTS AND PARTICLE PHYSICS
Authors: CLINE DAVID B.
Published: November 2004

We provide a brief review of the current situation concerning gamma ray bursts, with emphasis on the role that particle physics may play in the interesting phenomena. The current understanding of GRB origins allows for a large range of physical processes from primordial black hole evaporation to neutron star and black hole collisions. There does not seem to be a simple standard luminosity function and the burst times range from ms to 1000 s of seconds five orders of magnitude. It is likely that some type of fireball model is needed to explain the GRBs. No counterparts of GRB have been detected. We indicate some ways in which progress can be made in either the study of the fine time structure (~μs) or the detection of very high energy photons (>100 GeV to >100 TeV). We also indicate how a small but unique class of the GRB could come from primordial black hole evaporation.
NEW PERTURBATION THEORY FOR QUANTUM FIELD THEORY: CONVERGENT SERIES INSTEAD OF ASYMPTOTIC EXPANSIONS
Authors: BELOKUROV V.V. , SHAVGULIDZE E.T. , SOLOVYOV YU. P.
Published: November 2004

Asymptotic expansions, employed in quantum physics as series of perturbation theory, appear as a result of the representation of functional integrals by power series with respect to coupling constant. To derive these series one has to change the order of functional integration and infinite summation. In general, this procedure is incorrect and is responsible for the divergence of the asymptotic expansions.

In the present work, we suggest a method of construction of a new perturbation theory. In the framework of this perturbation theory, a convergent series corresponds to any physical quantity represented by a functional integral. The relations between the coefficients of these series and those of the asymptotic expansions are established.
A NEW MASS FORMULA FOR NG BOSONS IN QCD
Authors: CAHILL REGINALD T. , GUNNER SUSAN M.
Published: November 2004

An oftenly used mass formula for Nambu-Goldstone (NG) bosons in QCD, such as the pions, involves the condensate [Formula: see text], fπ and the quark current masses. We argue, within the context of the global color model to QCD, that this expression is wrong. Analysis of the interplay between the Dyson-Schwinger equation for the constituent quark effect and the Bethe-Salpeter equation for the NG boson results in a new mass formula.
STRINGS AS A MODEL FOR PARENT AND BABY UNIVERSES: TOTAL SPLITTING RATES
Authors: NIROV KH. S. , RUBAKOV V.A.
Published: November 2004

Emission of hard microscopic string (graviton) by an excited macroscopic string may be viewed as a model of branching of a (1+1)-dimensional baby universe off large parent one. We show that, apart from a trivial factor, the total emission rate is not suppressed by the size of the macroscopic string. This implies unsuppressed loss of quantum coherence in (1+1)-dimensional parent universe.
ON THE SHORT-TIME BEHAVIOR OF QUANTUM MECHANICAL SYSTEMS
Authors: NAKAZATO HIROMICHI , PASCAZIO SAVERIO
Published: November 2004

The conditions that yield deviations from a purely exponential behavior of a quantum mechanical system at short times are analyzed with special emphasis on the boundedness of the Hamiltonian. A few practical examples are considered. The problem of dissipation in quantum mechanics and quantum field theory is also briefly discussed.
RENORMALIZATION GROUP IMPROVED RADIATIVE CORRECTIONS TO THE SUPERSYMMETRIC HIGGS BOSON MASSES
Authors: GLADYSHEV A.V. , KAZAKOV D.I.
Published: November 2004

The one-loop radiative corrections to the Higgs boson potential in the MSSM, originating from the top quark and squark loops, are summed in the leading log approximation using the renormalization group (RG). The RG improved effective potential is minimized and the corrections to the CP-odd and CP-even Higgs boson masses are calculated. The resulting masses exhibit smoother top mass dependence than those calculated without RG summation. We have also found that for preferable values of the top mass the light Higgs mass does not exceed 100 GeV.
ON THE CLASSICAL STRING SOLUTIONS AND STRING/FIELD THEORY DUALITY II
Authors: ALEKSANDROVA D. , BOZHILOV P.
Published: November 2004

Based on the recently considered classical string configurations, in the framework of the semiclassical limit of the string/gauge theory correspondence, we describe a procedure for obtaining exact classical string solutions in general string theory backgrounds, when the string embedding coordinates depend nonlinearly on the worldsheet spatial parameter. The tensionless limit, corresponding to small 't Hooft coupling on the field theory side, is also considered. Applying the developed approach, we first reproduce some known results. Then, we find new string solutions — with two spins in AdS 5 black hole background and in AdS 5× S 5 with two spins and up to nine independent conserved R-charges.
ON PT-SYMMETRIC EXTENSIONS OF THE CALOGERO AND SUTHERLAND MODELS
Authors: BRIHAYE YVES , NININAHAZWE ANCILLA
Published: November 2004

The original Calogero and Sutherland models describe N quantum particles on the line interacting pairwise through an inverse square and an inverse sinus-square potential respectively. These models are well known to be integrable and solvable. Here we extend the Calogero and Sutherland Hamiltonians by means of new interactions which are PT-symmetric but not self-adjoint. Some of these new interactions lead to integrable PT-symmetric Hamiltonians. The algebraic properties of these interactions reveal further that they are also solvable. In addition, we consider PT-symmetric interactions which lead to new quasi-exactly-solvable deformations of the Calogero and Sutherland Hamiltonians.
PROBING MALDACENA–NUNEZ IN IR WITH p$\overline{\rm D3}$-BRANES
Authors: PAL SHESANSU SEKHAR
Published: November 2004

We probed Maldacena–Nunez solution in IR with p coincident anti-D3-branes and found that these probe branes become a fuzzy NS5-brane. Doing the dual analysis, i.e. from the NS5-brane point of view with the charge of p anti-D3-brane on the world-volume of NS5-brane, we showed that to leading order this potential matches with that of p anti-D3-branes and the potential on the NS5-brane has a stable minima and have also calculated the potential, from the NS5-brane point of view, for a small fluctuation along the radial direction.
STRUCTURE FORMATION FOR LIGHT ANNIHILATING DARK MATTER
Authors: BOEHM CÉLINE
Published: November 2004

Dark Matter (DM) is generally assumed to be made of weakly interacting massive particles. The latter are now embedded in the Cold Dark Matter (CDM) scenario. CDM does not necessarily mean collisionless DM though. In fact, DM with quite strong interactions may still appear as perfect CDM candidates. Alternatively DM particles with weak interactions may suffer from large collisional damping effects that make them looking alike Warm (or even Hot) Dark Matter (WDM) candidates. This is expected to be relevant, in particular, if DM is lighter than a proton. Light Dark Matter particles (LDMp) were introduced as an alternative to neutralinos. They become much more interesting after one realizes that they could potentially explain the 511 keV emission line detected and mapped by INTEGRAL/SPI in the center of the galaxy. Here, we study their consequences on structure formation.
ON THE RESPONSE OF COMPOSITE FERMIONS TO WEAK ELECTROSTATIC POTENTIALS
Authors: FARID BEHNAM
Published: November 2004

We establish that the response to static perturbations of two-dimensional electron systems (2DESs), exposed to magnetic field B, in states with the Landau-level filling fractions ν e close to one such as 1/2, is singularly different from that of 2DESs at small ‖B‖. Thus in addition to demonstrating the severe inadequacy of the treatment of composite fermions as non-interacting particles, we show, in contradiction to a recent theoretical finding, that the physical origin of the observed behavior of the dc longitudinal magneto-resistivity for ν e ≈1/2 in periodically modulated 2DESs remains to be determined.
WHY IRREVERSIBILITY? THE FORMULATION OF CLASSICAL AND QUANTUM MECHANICS FOR NONINTEGRABLE SYSTEMS
Authors: PRIGOGINE ILYA
Published: November 2004

Nonintegrable Poincaré systems with continuous spectrum (so-called Large Poincaré Systems, LPS) lead to the appearance of diffusive terms in the framework of dynamics. These terms break time symmetry. They lead, therefore, to limitations to classical trajectory dynamics and of wave functions. These diffusive terms correspond to well-defined classes of dynamical processes (i.e., so-called “vacuum-vacuum” transitions). The diffusive effects are amplified in situations corresponding to persistent interactions. As a result, we have to include already in the fundamental dynamical description the two aspects, probability and irreversibility, which are so conspicuous on the macroscopic level. We have to formulate both classical and quantum mechanics on the Liouville level of probability distributions (or density matrices). For integrable systems, we recover the usual formulations of classical or quantum mechanics. Instead of being irreducible concepts, which cannot be further analyzed, trajectories and wave functions appear as special solutions of the Liouville-von Neumann equations.

This extension of classical and quantum dynamics permits us to unify the two concepts of nature we inherited from the 19th century, based on the one hand on dynamical time-reversible laws and on the other on an evolutionary view associated to entropy. It leads also to a unified formulation of quantum theory avoiding the conventional dual structure based on Schrödinger’s equation on the one hand, and on the “collapse” of the wave function on the other. A dynamical interpretation is given to processes such as decoherence or approach to equilibrium without any appeal to extra dynamic considerations (such as the many-world theory, coarse graining or averaging over the environment). There is a striking parallelism between classical and quantum theory. For LPS we have, in general, both a “collapse” of trajectories and of wave functions for LPS. In both cases, we need a generalized formulation of dynamics in terms of probability distributions or density matrices.

Since the beginning of this century, we know that classical mechanics had to be generalized to take into account the existence of universal constants. We now see that classical as well as quantum mechanics also have to be extended to include unstable dynamical systems such as LPS. As a result, we achieve a new formulation of "laws of physics" dealing no more with certitudes but with probabilities. The formulation is appropriate to describe an open, evolving universe.
COMPUTATIONAL DYNAMICS OF ORDINARY DIFFERENTIAL EQUATIONS
Authors: POLIASHENKO MAXIM , AIDUN CYRUS K.
Published: November 2004

Discrete schemes, used to perform time integration of ODE’s, are expected to exhibit qualitatively ‘true’ dynamics in terms of the solutions and their stability. In past years, it has been discovered that such discretizations may cause spurious steady states and some explicit schemes may produce ‘computational chaos.’ In this study, we show that implicit time integration schemes, such as the backward Euler method, can also produce computationally chaotic solutions. Furthermore, we show that the opposite phenomenon may also take place both for explicit and for implicit schemes: computationally generated ‘spurious order’ may replace the true chaotic solution before the scheme becomes linearly unstable. The numerical solution may become chaotic again as the discretization step is further increased. The spurious computational order and chaos are discussed by solving low-dimensional dynamical systems, as well as a large system of ODE representing the solution to the Navier-Stokes equation. Our results support the point of view that the deviations in the behavior of the computed solution from the true solution has deterministic character with the time step playing the role of an artificial bifurcation parameter.
CHAOS IN THE TANG-MEES-CHUA MODEL OF THRESHOLD SYNCHRONISATION
Authors: SMALL A.J. , DUMBELL K.D. , SMITH P.D.
Published: November 2004

A simple mathematical model of the Threshold Synchronisation Mechanism (which we refer to here as the Tang-Mees-Chua Model) is studied. An auxiliary dynamical system is associated to the model in certain parameter ranges which have not been considered before. We prove that for part of this range the underlying dynamics are chaotic. In particular, we establish sensitivity to initial conditions, the existence of unstable periodic orbits of all periods and the presence of dense orbits. This theoretical work is supported by measurements of an experimental circuit and computer simulations.
TORUS DOUBLING IN FOUR WEAKLY COUPLED OSCILLATORS
Authors: ASHWIN PETER , SWIFT JAMES W.
Published: November 2004

We present evidence of torus doubling in systems of four weakly coupled oscillators. We assume that the oscillators are dissipative, so the system has an attracting invariant four-torus giving a Poincaré map on a section which is a three-torus. Using averaging, the asymptotic dynamics can be approximated by a flow on a three-torus. Thus it is possible to have period doubling in the averaged flow, corresponding to torus doubling in the unaveraged system; this is not possible for three or fewer oscillators in the weakly coupled limit. We observe torus-doubling bifurcations for a three-torus map and for a system of four coupled electronic oscillators.
SYNCHRONIZATION THEOREM FOR A CHAOTIC SYSTEM
Authors: SCHWEIZER JÖRG , KENNEDY MICHAEL PETER , HASLER MARTIN , DEDIEU HERVÉ
Published: November 2004

Since Pecora & Carroll [Pecora & Carroll, 1991; Carroll & Pecora, 1991] have shown that it is possible to synchronize chaotic systems by means of a drive-response partition of the systems, various authors have proposed synchronization schemes and possible secure communications applications [Dedieu et al., 1993, Oppenheim et al., 1992]. In most cases synchronization is proven by numerically computing the conditional Lyapunov exponents of the response system. In this work a new synchronization method using error-feedback is developed, where synchronization is provable using a global Lyapunov function. Furthermore, it is shown how this scheme can be applied to secure communication systems.
EFFICIENT NEIGHBOR SEARCHING IN NONLINEAR TIME SERIES ANALYSIS
Authors: SCHREIBER THOMAS
Published: November 2004

We want to encourage the use of fast algorithms to find nearest neighbors in k-dimensional space. We review methods which are particularly useful for the study of time-series data from chaotic systems. As an example, a simple box-assisted method and possible refinements are described in some detail. The efficiency of the method is compared to the naive approach and to a multidimensional tree for some exemplary data sets.
BIFURCATIONS IN A DISCONTINUOUS CIRCLE MAP: A THEORY FOR A CHAOTIC CARDIAC ARRHYTHMIA
Authors: BUB GIL , GLASS LEON
Published: November 2004

The dynamics of discontinuous circle maps are investigated in the context of modulated parasystole, a cardiac arrhythmia in which there is an interaction between normal (sinus) and abnormal (ectopic) pacemaking sites in the heart. A class of noninvertible discontinuous circle maps with slope greater than 1 displays banded chaos under certain conditions. Banded chaos in these maps is characterized by a zero rotation interval width in the presence of a positive Lyapunov exponent. The bifurcations of a simple piecewise linear circle map are investigated. Parameters that result in banded chaos are organized into discrete, nonoverlapping zones in the parameter space. We apply these results to analyze a circle map that models modulated parasystole. Analysis of the model is complicated by the fact that the map has slope less than 1 for part of its domain. However, numerical simulations indicate that the modulated parasystole map displays banded chaos over a wide range of parameters. Banded chaos in this map produces rhythms with a relatively constant sinus-ectopic coupling interval, long trains of uninterrupted sinus beats, and patterns of successive sinus beats between ectopic beats characteristic of those found clinically.
PERIODIC AND HOMOCLINIC ORBITS IN A TWO-PARAMETER UNFOLDING OF A HAMILTONIAN SYSTEM WITH A HOMOCLINIC ORBIT TO A SADDLE-CENTER
Authors: KOLTSOVA O. Yu. , LERMAN L.M.
Published: November 2004

For a two-degrees-of-freedom Hamiltonian system with a homoclinic orbit (loop) to a saddle-center we prove that the Poincaré map on a section to the loop within the Hamiltonian level containing a saddle-center is a twist map with discontinuity at the point of intersection with the loop. It explains the reason for existence of a countable set of periodic orbits near the loop. The types of these orbits are determined. We discover homoclinic doubling and tripling in a generic two-parameter Hamiltonian unfolding of such a Hamiltonian system. Besides this, we also study the nonautonomous linear Hamiltonian system obtained by means of the linearization of the original system at the loop. We derive the invariant formulation of the genericity condition that is needed for studying the original system.
SINGULARITIES OF THE PARAMETRIC PLANE OF AN n-DIMENSIONAL MAP.
Authors: CARCASSES JEAN-PIERRE
Published: November 2004

This paper uses the notion of “contour lines” in a parameter plane. A given contour line is related to a constant value of a “reduced multiplier” constructed from the elements of the Jacobian matrix associated with a given periodic point. The singularities type of such lines permit to determine a point of intersection of two bifurcation curves of same nature (flip or fold) and a point of tangency between a fold bifurcation curve and a flip bifurcation curve. When a third parameter varies, these singularities permit to determine the appearance (or disappearance) of a closed fold or flip bifurcation curve. Three different configurations of fold and flip bifurcation curves, centred round a cusp point of a fold curve, are considered. They are called saddle area, spring area, and crossroad area. The singularities type of the contour lines define the configuration types of these areas and, when a third parameter varies, the qualitative changes of such areas are directly identified.
MODELLING ECOLOGICAL SYSTEMS
Authors: RAI VIKAS
Published: November 2004

The paper introduces some new techniques which facilitate the study of nonlinear coupled ordinary differential equations modelling ecological systems. The strength and weaknesses of these techniques are discussed in detail. It also assesses the usefulness of “deterministic chaos” as a paradigm to understanding the dynamics of interacting populations.
CHAOTIC OSCILLATIONS OF A BUCKLED BEAM
Authors: RAGAZZO C. GROTTA
Published: November 2004

We show that the equation [Formula: see text], x ∈ (0, π), α < -1, which models transversal nonlinear vibrations of a buckled beam, has invariant four-dimensional manifolds of solutions containing periodic orbits with transversal homoclinic orbits to them. The basic tool used in the proof is a theorem concerning two degrees of freedom Hamiltonian systems with saddle-center loops.
EXTENSIONS OF THE NOTION OF CHAOTIC AREA IN SECOND-ORDER ENDOMORPHISMS
Authors: BARUGOLA A. , CATHALA J.C. , MIRA C.
Published: November 2004

Properties of chaotic areas (i.e. invariant domains of points positively stable in the Poisson’s sense) of non-invertible maps of the plane are studied by using the method of critical curves (two-dimensional extension of the notion of critical points in the one-dimensional case). The classical situation is that of a chaotic area bounded by a finite number of critical curves segments. This paper considers another class of chaotic areas bounded by the union of critical curves segments and segments of the unstable manifold of a saddle fixed point, or that of saddle cycle (periodic point). Different configurations are examined, as their bifurcations when a map parameter varies.