bluuebunny/crossref_metadata_2025 huggingface dataset:
FORMATION OF HIGH ENERGY MICROBEAMS AND THEIR APPLICATION TO MICROELECTRONICS
Authors: TAKAI MIKIO
Published: November 2004

Scanning nuclear microprobes using Rutherford backscattering (RBS) and particle-induced X-ray emission (PIXE) with light ions have been formed using variable objective slits and a magnetic quadrupole doublet. Beam optics, focusing techniques, factors limiting the minimum beam-spot size, and data acquisition systems are discussed. Two- and three-dimensional RBS mapping and channeling contrast mapping of processed semiconductor layers such as multilayered wiring and focused ion-implanted layers are demonstrated. Problems with microbeam analysis such as radiation damages due to the probe beams are discussed.
POSITION-SENSITIVE X-RAY DETECTOR SYSTEM FOR HIGH RESOLUTION PIXE MEASUREMENTS
Authors: Hamanaka H. , Hasegawa K. , Yamamoto Y.
Published: November 2004

A position-sensitive proportional counter with a carbon fiber anode, a goniometer and its associated electronics have been constructed to measure particle induced X-rays. The counter is easy to construct and its volume is about one order of magnitude smaller than a commercially available delay-line PSPC. This counter has good position linearity and uniform sensitivity distribution. Comparison is made between the new type of PSPC and an older one previously reported. It is shown that an enlargement of the X-ray window of the PSPC is effective for improving the detection efficiency.
OPTIMIZATION OF PARAMETRIC YIELD: A TUTORIAL
Authors: DIRECTOR STEPHEN W. , FELDMANN PETER , KRISHNA KANNAN
Published: November 2004

Yield loss can be characterized as either catastrophic or parametric. Catastrophic yield loss is primarily due to local disturbances, such as spot defects, that occur in a manufacturing process. On the other hand, parametric yield loss is due to global disturbances, such as mask misalignment. In this paper we briefly explore these two different types of yield loss and then review some methods that have been developed to maximize parametric yield.
NON-COMMUTATIVE SPHERES I
Authors: BRATTELI OLA , ELLIOTT GEORGE A. , EVANS DAVID E. , KISHIMOTO AKITAKA
Published: November 2004

We give an abstract characterization of the fixed point subalgebra of the irrational rotation algebra under the flip U → U−1, V → V−1, where U, V are the canonical unitaries generating the irrational rotation algebra. We also describe some basic properties of the fixed point subalgebra.
Molecular Transition Moment Calculations Using the Intermediate Operator Quasidegenerate Perturbation Theory
Authors: ZAITSEVSKII A.V. , DEMENT’EV A.I.
Published: November 2004

We developed a procedure for molecular transition one-electron property calculations based on the simple second-order QDPT approximation for the intermediate Hamiltonian and corresponding first-order approximation for intermediate effective property operators. To test its abilities, a series of transition moment calculations for simple molecules was performed and the results were compared with CI results.
MATHEMATICAL FORMULATIONS AND COMPUTER ENUMERATIONS OF POLYMER MODELS WITH LOOPS
Authors: LIM HWA A.
Published: November 2004

The mathematical formalisms and computer enumerations of two polymeric models: trails and silhouettes are presented. Trails have been quite extensively studied, but their equivalence class, silhouettes are less familiar. By drawing parallelism from n→0 magnetic analog, the tricritical properties of silhouettes are studied both analytically and numerically. The tricriticality of trails, which is inaccessible by a renormalization group analysis in ε=4−D dimensions, can therefore only be investigated numerically. The tricritical exponents thus obtained indicate that trails belong to a distinct universality class from silhouettes.
THE MULTICANONICAL ENSEMBLE: A NEW APPROACH TO COMPUTER SIMULATIONS
Authors: BERG BERND A.
Published: November 2004

The multicanonical ensemble is reviewed. Simulations of this ensemble promise improvements for a wide range of systems. Applications to first order phase transitions and spin glasses are summarized.
MOLECULAR DYNAMICS SIMULATIONS OF GRANULAR MATERIALS ON THE INTEL iPSC/860
Authors: RISTOW GERALD H.
Published: November 2004

In this paper we present an efficient algorithm to perform Molecular Dynamics simulations on a distributed memory parallel computer, the Intel iPSC/860. The proposed model describes the flow properties of granular materials in two dimensions. The specific implementation on a 32 node iPSC/860, especially the message passing and load balancing algorithms, are discussed in detail. Performance data are shown for different computers and varying node numbers of the iPSC/860. As a physical example we calculate some properties of the outflow behavior from a two-dimensional hopper and we discuss possible extensions of our model to three dimensions. Our simulations show that Molecular Dynamics simulations can be implemented quite efficiently on a distributed memory parallel computer if one assures load balancing and optimizes the internode communications.
LINEAR SCHEDULING IS NEARLY OPTIMAL
Authors: DARTE ALAIN , KHACHIYAN LEONID , ROBERT YVES
Published: November 2004

This paper deals with the problem of finding optimal schedulings for uniform dependence algorithms. Given a convex domain, let Tf be the total time needed to execute all computations using the free (greedy) schedule and let Tl be the total time needed to execute all computations using the optimal linear schedule. Our main result is to bound Tl/Tf and Tl − Tf for sufficiently "fat" domains.
MENDED CHIRAL SYMMETRY AND THE LINEAR SIGMA MODEL IN ONE-LOOP ORDER
Authors: SCADRON M.D.
Published: November 2004

It is shown that the linear σ-model in one-loop order in the chiral limit recovers meson masses mπ=0, mσ=2mqk (NJL), [Formula: see text] (KSRF), along with couplings [Formula: see text] (VMD universality) and Weinberg’s mended chiral symmetry decay width relation Γσ=(9/2)Γρ. The linear σ-model combined quark and meson loops also properly predict the radiative decays π0→2γ, π→evγ and δ0(983)→2γ.
S-MATRIX FROM THE METAPLECTIC REPRESENTATION
Authors: VÁRILLY JOSEPH C. , GRACIA-BONDÍA JOSÉ M.
Published: November 2004

We show how the S-matrix for bosons in an external field can be derived directly from the infinite-dimensional metaplectic representation, in terms of the classical scattering operator.
PION INTERFEROMETRY AS A PROBE OF TIME VARYING SOURCES
Authors: CASADO J.A.
Published: November 2004

We discuss the way in which Bose-Einstein correlations among identical pions are affected by the presence of an explicit time dependence in the pion source’s space-time distribution. A particular functional form for this distribution has been assumed in order to compute both the longitudinal and transverse radii. In addition, the variations of these radii with the two pions center-of-mass rapidity is studied.
FRACTIONAL CHARGED COLOR SINGLET STATES AND STRING UNIFICATION
Authors: BAILIN DAVID , LOVE ALEX
Published: November 2004

The question of whether contributions of exotic multiplets of the gauge group to the running of gauge coupling constants from the string scale to low energy can lead to consistency with the precision low energy values of gauge couplings is discussed for theories with SO(6)×SO(4), SU(3)×SU(3)×SU(3) and flipped SU(5)×U(1) grand unification.
SPLIT INVOLUTION AND SECOND CLASS CONSTRAINTS
Authors: BATALIN I.A. , LYAKHOVICH S.L. , TYUTIN I.V.
Published: November 2004

The new quantization scheme is proposed for theories with second class constraints. The formalism possesses the properties intermediate between those of the conversion method and quantum deformation of the Dirac bracket: on the one hand, all the phase variable operators have nonsingular commutators while the physical states are determined by weak equations; on the other hand, no extra degrees of freedom are introduced.
BRST-FIXED POINTS AND TOPOLOGICAL CONFORMAL SYMMETRY
Authors: NAKATSU TOSHIO , SUGAWARA YUJI
Published: November 2004

We study the twisted version of the supersymmetric G/T = SU (n)/ U (1)⊗(n−1) gauged Wess-Zumino-Witten model. By studying its fixed points under BRST transformation this model is shown to be reduced to a simple topological Field theory, that is, the topological matter system in the K. Li's theory of two-dimensional gravity for the case of n = 2, and its generalization for n ≥ 3.
THERMODYNAMICS OF THE QUANTUM BOSONIC MEMBRANE
Authors: ODINTSOV S. D.
Published: November 2004

The thermodynamics of the semiclassical bosonic membrane is discussed. Using the S-representation for free energy the attempt is given to construct the F-representatian. The possibility of dual symmetry for free energy is investigated, the dual-symmetric generalization of the free energy is presented. The cut-off dependence of the Hagedorn temperature is discussed.
DIFFERENTIAL RENORMALIZATION OF THE WESS-ZUMINO MODEL
Authors: HAAGENSEN PETER E.
Published: November 2004

We apply the recently developed method of differential renormalization to the Wess-Zumino model. From the explicit calculation of a finite, renormalized effective action, the β-function is computed to three loops and is found to agree with previous existing results. As a further, non-trivial check of the method, the Callan-Symanzik equations are also verified to that loop order. Finally, we argue that differential renormalization presents advantages over other superspace renormalization methods, in that it avoids both the ambiguities inherent to supersymmetric regularization by dimensional reduction (SRDR), and the complications of virtually all other supersymmetric regulators.
SCALAR TOP PRODUCTION VIA BOSON-GLUON FUSION AT HERA
Authors: KOBAYASHI TETSURO , KON TADASHI , NAKAMURA KEIICHIRO , SUZUKI TAKESHI
Published: November 2004

We investigate the production of the light scalar top quark [Formula: see text] via boson-gluon fusion at ep collider HERA, based on the minimal supersymmetric standard model. The cross-section is obtained by both an exact tree level calculation and the Weizsäcker-Williams approximation. It is shown that the total cross-section is larger than 0.1pb if [Formula: see text] and does not depend on the mixing angle θt of scalar top quarks. This enables us to search a possible region of parameters for existence of light scalar top at HERA in a wider parameter space [Formula: see text] than LEP.
WORMHOLE SOLUTIONS IN R1×S1×S2 TOPOLOGICAL SPACE
Authors: CHAKRABORTY SUBENOY
Published: November 2004

Wormhole solutions are discussed for two different physical situations in the background of a homogeneous anisotropic space-time. In the first case, the wormholes are solutions of the Euclidean Einstein equations with a cosmological constant and a two-index anti-symmetric tensor for monopole configuration on a space with three-surface of topology S1×S2. In the second step, conformal scalar field is coupled to gravity and wormhole are considered for both λ=0 and λ>0. These results are analogous to the wormhole solutions for FRW metric.
A DIRECT HEAT KERNEL METHOD FOR GENERATING THE CONSERVED QUANTITIES OF THE ZS-AKNS SYSTEM
Authors: WOSPAKRIK HANS J.
Published: November 2004

A heat kernel formulation of an isospectral Lax operator for generating the infinite conserved quantities of the ZS-AKNS two-dimensional system is presented. Using the Nepomechie direct method for computing the asymptotic expansion of the diagonal part of the heat kernel, one obtains a non-recursive formula for the conserved quantities.
MAGNETIC RESONANCES OF THE e+e−-SYSTEM
Authors: DEHNEN H. , SHAHIN M.
Published: November 2004

The possibility of the existence of magnetically bound positronium states (superpositronium) is investigated starting from Barut’s relativistic two-body equations. For the total angular momentum j=0 quasi-bound energy states are found in the form of resonances of the cross-section calculated with the use of the phase of the scattering states. The energies are in agreement with the observed kinetic energy of the disintegration electrons or positrons in the heavy-ion collision experiments. From the width of the resonances the lifetime of the quasi-bound states can be estimated. Really bound superpositronium states could not be found.
FIELD-THEORETICAL ANALYSIS OF ANYONIC SUPERCONDUCTIVITY
Authors: LYKKEN JOSEPH D. , SONNENSCHEIN JACOB , WEISS NATHAN
Published: November 2004

We derive several results pertaining to anyonic superconductivity as described by a Chern-Simons field theory. (1) The renormalized Chern-Simons term at finite density is shown to vanish when the renormalized coefficient at zero density takes values Ne2/2π. This is the field-theoretical requirement to have a massless pole in the current-current correlator. We can then show that in the Chern-Simons description a system of charged anyons at zero temperature is a superconductor. This result is shown to hold to all orders in perturbation theory by generalizing a nonrenormalization theorem of the zero density case. (2) At finite temperature the renormalized Chern-Simons term does not vanish at the one-loop perturbative level. We compute the mass of this apparent “pseudo-Goldstone mode”. We also exhibit an effect suggestive of critical behavior, for this same system, at a nonzero Tc. We discuss the possible implications of these perturbative results. (3) A low energy effective action for an anyonic superconductor is derived directly from Chern-Simons field theory. Several P and T violating effects occur.
N=2 LANDAU-GINZBURG VS. CALABI-YAU σ-MODELS: NON-PERTURBATIVE ASPECTS
Authors: CECOTTI S.
Published: November 2004

We discuss some nonperturbative aspects of the correspondence between N=2 Landau-Ginzburg orbifolds and Calabi-Yau σ-models. We suggest that the correct framework is Deligne’s theory of mixed Hodge structures (closely related to catastrophe theory). We derive a general topological formula for the chiral ring OPE coefficients of any Landau-Ginzburg model, including the absolute normalization. This follows from the identification of spectral flow with Grothendieck’s local duality. Wherever the LG model has a CY interpretation, its OPE coefficients are equal to those of the σ-model as given by intersection theory, including normalization. We discuss at length the tricky case of a number of LG fields greater than c/3+2, presenting explicit examples. In passing, we get many results about the geometry of moduli spaces for such conformal theories. We explain the beautiful algebraic geometry connected with a remarkable model pointed out by Vafa, and its relations with moduli space geometry.
SEARCH FOR CHARGED HEAVY LEPTONS WITH ARBITRARY NEUTRINO MASSES IN e+e− ANNIHILATIONS AT $\sqrt{s} = 50 - 60.8~{\rm GeV}$
Authors: Kim G.N. , Smith J.R. , Breedon R.E. , Ko Winston , Lander R.L. , Maeshima K. , Malchow R.L. , Rowe J. , Stuart D. , Imlay R. , Kirk P. , Lim J. , McNeil R.R. , Metcalf W. , Myung S.S. , Cheng C.P. , Gu P. , Li J. , Li Y.K. , Ye M.H. , Zhu Y.C. , Abashian A. , Gotow K. , Hu K.P. , Low E.H. , Mattson M.E. , Piilonen L. , Sterner K.L. , Lusin S. , Rosenfeld C. , Wang A.T.M. , Wilson S. , Frautschi M. , Kagan H. , Kass R. , Trahern C.G. , Abe K. , Fujii Y. , Higashi Y. , Kim S.K. , Kurihara Y. , Maki A. , Nozaki T. , Omori T. , Sagawa H. , Sakai Y. , Sugimoto Y. , Takaiwa Y. , Terada S. , Walker R. , Kajino F. , Perticone D. , Poling R. , Thomas T. , Ishi Y. , Miyano K. , Miyata H. , Sasaki T. , Yamashita Y. , Bacala A. , Liu J. , Park I.H. , Sannes F. , Schnetzer S. , Stone R. , Vinson J. , Auchincloss P. , Blanis D. , Bodek A. , Budd H. , Eno S. , Fry C.A. , Harada H. , Ho Y.H. , Kim B.J. , Kim Y.K. , Kumita T. , Mori T. , Olsen S.L. , Shaw N.M. , Sill A. , Thorndike E.H. , Ueno K. , Velissaris C. , Zheng H.W. , Kobayashi S. , Murakami A. , Kang J.S. , Kim H.J. , Lee M.H. , Han D.H. , Kim E.J. , Son D. , Matsumoto S. , Tanaka R. , Tomioka K. , Ishizuka T. , Ohta K.
Published: November 2004

Results of a search for the pair production of charged heavy leptons in e+e− annihilations over the center-of-mass energy range of 50 to 60.8 GeV are reported. We assume that the leptons are of the sequential type but have allowed for the case where the associated neutrino might be massive. Separate searches for evidence for decays to hadronic and leptonic final states, searches specialized for the case where the charged lepton and its associated neutrino are close in mass, and a search for stable heavy leptons have uncovered no evidence for the production of such particles at these energies. Mass limits for heavy leptons and their associated neutrinos are determined for a range of hadronic and leptonic decay branching fractions. A sequential charged heavy lepton with mass between 12.6 and 29.6 GeV/c2 and with massless neutrino is excluded at the 95% confidence level.
EVEN INTEGER LATTICES FROM SIMPLY LACED GKO COSETS
Authors: AULAKH CHARANJIT S. , MAHAPATRA SWAPNA
Published: November 2004

We determine the branching functions (“coset characters”) for the decomposition of the characters, at genus one, of level-one Kac-Moody algebras based on simply laced simple Lie algebras (ĝ1) into the characters of their level-one subalgebras (ĥ1) to be (improved) theta functions on certain even integer lattices. These characters support unitary representations of the modular group and provide explicit examples of the characters of Gaussian RCFT associated with an arbitrary even integer lattice, as discussed in Refs. 1 and 9.
SPECTRUM GENERATING QUANTUM GROUP OF THE HARMONIC OSCILLATOR
Authors: MACFARLANE A.J. , MAJID SHAHN
Published: November 2004

Some conceptual problems for the interpretation of osp(1|2) as a spectrum generating algebra for the bosonic harmonic oscillator are resolved using quantum groups. We show that in place of the superalgebra osp(1|2) one may work equivalently with its bosonization, bosp(1|2), which we introduce. It is a quantum group and provides a purely bosonic spectrum generating algebra for the harmonic oscillator. The construction is extended to include the q-deformed situation also.
ON THE USE OF DUAL REGGEON VERTICES FOR UNTWISTED AND TWISTED SCALAR FIELDS
Authors: ENGBERG NICLAS , NILSSON BENGT E.W. , SUNDELL PER
Published: November 2004

We point out certain simplifying features in the calculation of higher genus multi-Reggeon vertices for the (untwisted) bosonic string which appear when using the dual Reggeon vertex instead of the standard three vertex. In the case of twisted scalar fields we show that the form of the twisted (one-particle) emission vertex recently discussed by Frenkel, Lepowsky and Meurman, Corrigan and Hollowood, and by Dolan, Goddard and Montague is a direct consequence of a special normal ordering prescription which is closely related to the one used earlier in the fermion emission vertex and its generalization the dual Ramond vertex. We also explain why this particular prescription must be chosen. Finally we derive the dual Reggeon vertex for twisted scalars.
COMBINATORICS OF THE MODULAR GROUP II THE KONTSEVICH INTEGRALS
Authors: ITZYKSON C. , ZUBER J.-B.
Published: November 2004

We study algebraic aspects of Kontsevich integrals as generating functions for intersection theory over moduli space and review the derivation of Virasoro and KdV constraints.
NONCOMMUTATIVE GEOMETRY AND GRADED ALGEBRAS IN ELECTROWEAK INTERACTIONS
Authors: COQUEREAUX R. , FARÈSE G. ESPOSITO , SCHECK F.
Published: November 2004

The Standard Model of Electroweak Interactions can be described by a generalized Yang-Mills field incorporating both the usual gauge bosons and the Higgs fields. The graded derivative by means of which the Yang-Mills field strength is constructed involves both a differential acting on space-time and a differential acting on an associative graded algebra of matrices. The square of the curvature for the corresponding covariant derivative yields the bosonic Lagrangian of the Standard Model. We show how to recover the whole fermionic part of the Standard Model in this framework. Quarks and leptons fit naturally into the smallest typical and nontypical irreducible representations of the graded algebra Lie SU(2|1) associated with the above associative ℤ2-graded algebra. The existence of reducible indecomposable representations leads naturally to flavor mixing in the quark sector, possibility of existence for a right neutrino and possible mixing in the leptonic sector. We therefore bridge the gap between noncommutative geometry and graded Lie algebras. The Z2 grading refers to left and right chiralities in the fermionic sector and to even and odd forms in the bosonic sector. Supergauge transformations could only be defined in an extension of the theory incorporating tensor fields of higher rank. The Standard Model contains only one-forms and zero-forms in the bosonic sector, therefore only the even part of the above graded Lie algebra — i.e. Lie[SU(2)×U(1)] — acts.
SOq(N, R)-SYMMETRIC HARMONIC OSCILLATOR ON THE N-DIM REAL QUANTUM EUCLIDEAN SPACE
Authors: FIORE GAETANO
Published: November 2004

The Schroedinger equation for the [w.r.t. SOq(N, R)] isotropic harmonic oscillator on the N-dimensional real quantum Euclidean space [Formula: see text] is algebraically solved. The Hamiltonian and the other operators are built in terms of the deformed coordinates and derivatives characterizing this noncommutative geometrical space and its two differential calculi. The spectrum and the eigenfunctions (the q-deformed Hermite functions) are studied.
STOCHASTIC QUANTIZATION OF FERMIONIC THEORIES: RENORMALIZATION OF THE MASSIVE THIRRING MODEL
Authors: BRUNELLI J.C.
Published: November 2004

Using the Langevin approach for stochastic processes, we study the renormalizability of the massive Thirring model. At finite fictitious time, we prove the absence of induced quadrilinear counterterms by verifying the cancellation of the divergencies of graphs with four external lines. This implies that the vanishing of the renormalization group beta function already occurs at finite times.
GENERALIZED N=2 SUPER KdV HIERACHIES: LIE SUPERALGEBRAIC METHODS AND SCALAR SUPER LAX FORMALISM
Authors: INAMI TAKEO , KANNO HIROAKI
Published: November 2004

Generalized N=2 super KdV hierarchies are constructed based on super Lax equations associated with Lie superalgebras SL(n|n)(1). The equivalence of the scalar super Lax formalism and the Lie superalgebraic method is derived by taking account of gauge transformations regarding the centre of SL(n|n)(1). We show that generalized N=2 super KdV hierarchies are related to the even reductions of the super KP hierarchy.
FERMIONS AND LINK INVARIANTS
Authors: Kauffman L. , Saleur H.
Published: November 2004

This paper deals with various aspects of knot theory when fermionic degrees of freedom are taken into account in the braid group representations and in the state models. We discuss how the Ř matrix for the Alexander polynomial arises from the Fox differential calculus, and how it is related to the quantum group Uqgl(1,1). We investigate new families of solutions of the Yang Baxter equation obtained from "linear" representations of the braid group and exterior algebra. We study state models associated with Uqsl(n,m), and in the case n=m=1 a state model for the multivariable Alexander polynomial. We consider invariants of links in solid handlebodies and show how the non trivial topology lifts the boson fermion degeneracy that is present in S3. We use "gauge like" changes of basis to obtain invariants in thickened surfaces Σ×[0,1].
SDIFF(2) KP HIERARCHY
Authors: TAKASAKI KANEHISA , TAKEBE TAKASHI
Published: November 2004

An analogue of the KP hierarchy, the SDiff(2) KP hierarchy, related to the group of area-preserving diffeomorphisms on a cylinder is proposed. An improved Lax formalism of the KP hierarchy is shown to give a prototype of this new hierarchy. Two important potentials, S and τ, are introduced. The latter is a counterpart of the tau function of the ordinary KP hierarchy. A Riemann-Hilbert problem relative to the group of area-diffeomorphisms gives a twistor theoretical description (nonlinear gravition construction) of general solutions. A special family of solutions related to topological minimal models are identified in the framework of the Riemann-Hilbert problem. Further, infinitesimal symmetries of the hierarchy are constructed. At the level of the tau function, these symmetries obey anomalous commutation relations, hence leads to a central extension of the algebra of infinitesimal area-preserving diffeomorphisms (or of the associated Poisson algebra).
KILLING FORMS, HARISH-CHANDRA ISOMORPHISMS, AND UNIVERSAL R-MATRICES FOR QUANTUM ALGEBRAS
Authors: TANISAKI TOSHIYUKI
Published: November 2004

We describe the Killing form of the quantum algebra using the duality pairing between the plus and the minus parts, and give a structure theorem for the center. A detailed proof of the existence of the universal R-matrix (Drinfeld's theorem) is also given.
THE DYNAMICS OF A QUANTUM CIRCUIT CONNECTED TO A CLASSICAL LOSSY OSCILLATOR
Authors: SPILLER T. P. , POULTON D. A. , CLARK T. D. , PRANCE R. J. , PRANCE H.
Published: November 2004

We calculate the dynamical behaviour of a classical circuit weakly coupled to a macroscopic quantum circuit, in the adiabatic limit. The quantum circuit generates characteristic signatures in these dynamics. The relevance of these results to SQUID magnetometer experiments is discussed.
FERMIONIC STRINGS AND THE EXACT SOLUTION OF EDGE MODELS IN THREE DIMENSIONS
Authors: ORLAND PETER
Published: November 2004

A three-dimensional statistical system, called here the six-edge model, is shown, for a particular domain of parameters, to be equivalent to a theory of Fermionic strings. This model has a local U(1) gauge invariance, similiar to the global invariance of the two-dimensional six-vertex model. Further restricting the parameters gives a system named here the five-edge model, which is exactly solvable. The conformal anomaly of the surfaces is calculated. The transfer matrix is diagonalized, and the free energy, phase diagram and correlation length are determined exactly. The surfaces of the model display a roughening transition similiar to that analyzed by Blöte, Hilhorst and Nienhuis.
ORDERING PROBLEM FOR THE ANTIFERROMAGNETIC POTTS MODEL: T=0 MONTE-CARLO STUDIES
Authors: BAKAEV A.V. , KABANOVICH V.I. , KURBATOV A.M.
Published: November 2004

AF Potts model MC dynamics at T=0 is considered. It is shown that q=3 square lattice and q=4 triangular lattice models are frozen for local MC algorithm. The nature of the previously discussed long-range order phases is examined and entropically favored states are considered.
NUMERICAL EVIDENCE OF A FIRST-ORDER TRANSITION IN A BRANCHED POLYMER: FINITE SIZE EFFECT AT THE TRANSITION
Authors: GUJRATI P.D. , ZHU Y.
Published: November 2004

Within the ε-expansion scheme, we argue that the upper critical dimension for the continuous transition (if it exists) in the dilute limit of branched polymers should be du=4. However, Monte-Carlo simulations in d=2, 3 and 4 for a single branched polymer on a finite lattice show evidence of a first-order transition at K=K0 and not a continuous transition which we observe for a linear polymer. Here, K represents bond activity. Our extensive simulation in d=2 is compared with previously known results. The existence of a first-order transition at K0 is not inconsistent with power-law singularities as [Formula: see text], which have been observed by various workers. However, for K<K0, the self-similarity which is a prerequisite of a fractal (i.e., a critical) object is only approximate. At K=K0 the branched polymer is a regular, compact object and not a fractal. In constrast, a linear polymer is a fractal at the transition, as is expected and as our simulation also suggests. Thus, our work shows that the order of the thermodynamic limit N→∞ and K→K0 is important, provided the transition remains first-order in the thermodynamic limit. In previous works, one considers [Formula: see text] after the limit N→∞ has already been taken, whereas we are interested in K→K0, followed by N→∞.
COMBINATORIAL AND TOPOLOGICAL PHASE STRUCTURE OF NON-PERTURBATIVE n-DIMENSIONAL QUANTUM GRAVITY
Authors: CARFORA M. , MARTELLINI M. , MARZUOLI A.
Published: November 2004

We provide a non-perturbative geometrical characterization of the partition function of ndimensional quantum gravity based on a rough classification of Riemannian geometries. We show that, under natural geometrical constraints, the theory admits a continuum limit with a non-trivial phase structure parametrized by the homotopy types of the class of manifolds considered. The results obtained qualitatively coincide, when specialized to dimension two, with those of two-dimensional quantum gravity models based on random triangulations of surfaces.
EXPERIMENTAL MEASUREMENTS OF THE DYNAMIC TORQUE RESPONSE OF AN ELECTRORHEOLOGICAL FLUID IN THE SHEAR MODE
Authors: HOSSEINI-SIANAKI A. , BULLOUGH W. A. , FIROOZIAN R. , MAKIN J. , TOZER R. C.
Published: November 2004

Experimental measurements of the time response of an electrorheological fluid in a high natural frequency Couette type of rheometer system are reported for both step and variable frequency, DC biased small amplitude sine wave voltage excitation.

The effects of both the speed of the rotating element of the rheometer and the magnitude of its voltage relative to the stationary element as well as the fluid temperature level are presented for time, frequency and steady domains. For a given DC voltage level and over the range of tests carried out, the fluid response time improves considerably with both increase in the temperature and speed, whereas the effect on the magnitude of the steady state ER torque value is marginal. Very encouraging results are obtained when the performance of the fluid with regard to the step tests are compared with results of transformed data taken from a larger and more practical clutch system and those acquired from the same fluid but in the flow mode valve arrangement.
ELECTRON-ELECTRON INTERACTIONS: WARD IDENTITIES
Authors: MAHAN G.D.
Published: November 2004

We derive several new identities for the correlation functions which are evaluated for electron-electron interactions. These exact results are useful for checking numerous approximations.
Atomic structure of metallic clusters of medium size
Authors: Alonso J.A. , Glossman M.D. , Iñiguez M.P.
Published: November 2004

We have used Density Functional Theory and the Spherically Averaged Pseudopotential (SAPS) model to study the relative stabilities of sodium clusters with. different atomic arrangements in the size range N ≤340. Starting with perfect crystalline clusters with filled atomic shells we find that small distortions of the geometry strongly enhance their stability. However in the size range studied in this work the distorted crystalline structures are not the absolute energy minima. These are, instead, non-crystalline structures obtained by energy minimization without any structural constraints. In particular, non-crystalline clusters with a number of electrons able to give filled electronic shells are the most stable clusters. The crossover between magic numbers of electronic origin (clusters with filled electronic shells) and magic numbers of atomic origin (crystalline structures with filled atomic shells) has not yet taken place in the size range studied here and should occur for larger sizes.
METASTABLE PHOTOINDUCED SUPERCONDUCTIVITY IN YBaCuO FILMS CLOSE TO METAL-SEMICONDUCTOR TRANSITION
Authors: KREINES N.M. , KUDINOV V.I.
Published: November 2004

The paper gives a brief overview of experiments concerned with the metastable photoinduced superconductivity phenomenon that have been recently discovered. As evidenced, illuminating the YBa 2 Cu 3 O 6.4 films by visible light to enhancement of metal properties and occurrence of a superconducting transition at low temperatures. Both the temperature of the onset of a superconducting transition and the superconducting phase space in the films rise with the increase of exposure dose. The phenomena discovered are due to photoexcitation of extra mobile holes in the CuO 2 plane allowing a new metastable superconducting phase to be initiated (photodoping). Also discussed are microscopic mechanisms of photoinduced superconductivity.
dc SUSCEPTIBILITY AND CURRENT PATH IN Ag-SHEATHED Bi(Pb)2223 WIRES
Authors: XUE Y.Y. , FENG F. , TAO Y.K. , WANG Y.Q. , HOR P.H. , CHU C.W.
Published: November 2004

dc susceptibility has been used to interpret the percolation behavior of several Ag-sheathed 3-layer Bi(Pb)-compound wires. The wires have been synthesized to obtain relatively inferior transport critical current densities (J c ’s) from 0 to 8×103 A/cm 2 at 77 K and 0 T. Combined with SEM and X-ray data, our observations suggest that the superconductive cores in the wires are highly textured grains with a considerable fraction of voids. The neighboring Bi-grains in the same plane are frequently bridged by grains in the next layer. The transport supercurrent, therefore, flows in a zig-zag pattern across the grain boundaries along the c-direction. The large and relatively clean grain boundaries in the c-planes help to achieve a rather large J c under optimum conditions. However, in such a percolation figure, the intergrowth or layered inclusions become one of the main factors to limit J c .
NUMERICAL STUDIES OF RESISTANCE AND CONDUCTANCE FLUCTUATIONS IN CHAINS WITH CONTINUOUS DISORDERED POTENTIALS
Authors: MANNA SUSIL KUMAR , MOOKERJEE ABHIJIT
Published: November 2004

We have studied the behaviour of resistance and conductance vfluctuation in disordered chains, using the invariant embedding approach. Length dependence of the average ln (1 + ρ), where ρ is the resistance of the sample, is linear for all values of ρ. We have shown that in the mesoscopic regime the conductance fluctuation in this model is almost constant with length and takes a value about 0.26 independent of the degree of disorder. These fluctuations die down at large lengths beyond mesoscopic region. This is entirely because of coherent backscattering due to disorder and has nothing to do with inelastic scattering which is absent in our model.
CAVITY QUANTUM ELECTRODYNAMIC ENHANCEMENT OF SPONTANEOUS AND STIMULATED EMISSION IN MICRODROPLETS
Authors: CAMPILLO A. J. , EVERSOLE J. D. , LIN H.-B.
Published: November 2004

A brief review is presented of recent developments in the field of cavity quantum electrodynamic emission enhancement in liquid microdroplets. These include spectral changes, emission lifetime modification, enhanced energy transfer, and enhanced lasing and Raman gains.
TURING STRUCTURES IN CATALYTIC SURFACE REACTIONS: THE FACETTING OF Pt(110) IN CO + O2
Authors: IMBIHL R.
Published: November 2004

Exposing a Pt(110) surface to catalytic CO oxidation causes the development of a regular facet pattern of microscopic dimensions which has been identified as a dissipative structure of the Turing type. The primary step in the facetting process is considered to be the [Formula: see text] phase transition which is also responsible for the occurrence of kinetic oscillations in the same system. This interpretation was confirmed in a Monte Carlo simulation which was based on the Langmuir-Hinshelwood mechanism of catalytic CO oxidation and the properties of the surface phase transition. Thus a detailed microscopic description is available for the process by which a Turing structure is formed during a surface reaction.
SENSORY INFORMATION PROCESSING BY NOISY BISTABLE NEURONS
Authors: LONGTIN ANDRÉ , BULSARA ADI , MOSS FRANK
Published: November 2004

Many neurons in the central nervous system and at the sensory periphery receive periodic input. The neural activity of interest here is one which may be called "statistical phase-locking", where the neuron fires preferentially near a given phase of the stimulus, but skips a random number of stimulus cycles between successive firings. It is shown that intervals between successive firings are distributed according to the same density as that of residence times in bistable noisy systems, provided these times are computed from suitably chosen interwell transitions. This brief review further makes this connection plausible by relating properties of neurons to those of bistable systems. Further it looks at the question of what role noise and possibly stochastic resonance, which can arise in this context, may play in information processing at the sensory neuron level.
THE GENERALIZED THERMODYNAMIC FORMALISM APPLIED TO HYPERBOLIC AND NONHYPERBOLIC MODELS
Authors: PARISI J. , STOOP R.
Published: November 2004

In this contribution, scaling properties of hyperbolic and nonhyperbolic model systems are discussed by using the generalized thermodynamic formalism. The central quantity for the investigation is the generalized entropy function. With the help of this approach, insight into the possible occurrence of phase transitions in the various entropy-like scaling functions can be gained. It is shown how this effect is determined by the existence of a critical line in the surface described by the generalized entropy function.
JAYNES-CUMMINGS SPECTRA BY LINEARIZATION WITH CLIFFORD VARIABLES
Authors: RASTELLO MARIA LUISA
Published: November 2004

The effect of rotating-wave and counter-rotating terms in the energy spectrum of a single two-level atom interacting with a quantized field is investigated within a fermionic linearization scheme involving Clifford variables.

After reproducing the Jaynes-Cummings results in the rotating-wave approximation, the counter-rotating terms are shown to determine an energy spectrum sensitive to low photon-number conditions.
FIELD-INDUCED ANISOTROPY IN MICROWAVE ABSORPTION OF HIGH-TcPOWDERS INTERCALATED BY ORGANIC MOLECULES
Authors: GRIGORYAN L.S. , CHAKRAVARTY N. , CAPRI A.Z.
Published: November 2004

The room-temperature microwave absorption spectra of the benzene- and nickel phthalocyanine-intercalated powder samples of Bi- and Tl-oxide high-Tc superconductors have been studied. The powder samples become magnetically anisotropic after magnetization by external dc field. Analysis of the angular variations of the microwave absorption spectra of the magnetized powder samples in three-orthogonal planes has shown that the angular curves are asymmetric with respect to the external dc field, indicating that the magnetic moment induced in the sample is not exactly collinear with the external dc field. The origin of the observed anisotropic microwave absorption is tentatively ascribed to the persistent orbital moments, associated with the circulation of π-electrons within the conjugated rings of the guest organic molecules.
RELAXATION MODES OF THE CONTACT LINE IN SITUATION OF PARTIAL WETTING
Authors: ONDARÇUHU THIERRY
Published: November 2004

We present here a brief review of theoretical and experimental results concerning the relaxation modes of the contact line between a solid, a liquid and a gas. This study constitutes a first step in view of the elucidation of wetting of non-homogeneous surfaces. The dispersion law giving the characteristic relaxation rate as a function of the wavevector of the deformation is derived from the balance of elastic driving force and dissipation processes. The very anomalous form of the dispersion law is confirmed by experimental measurements achieved on model surfaces using an original method to deform periodically the line.
THE RANDOM NEURAL NETWORK MODEL FOR TEXTURE GENERATION
Authors: ATALAY VOLKAN , GELENBE EROL , YALABIK NESE
Published: November 2004

The generation of artifical textures is a useful function in image synthesis systems. The purpose of this paper is to describe the use of the random neural network (RN) model developed by Gelenbe to generate various textures having different characteristics. An eight parameter model, based on a choice of the local interaction parameters between neighbouring neurons in the plane, is proposed. Numerical iterations of the field equations of the neural network model, starting with a randomly generated gray-level image, are shown to produce textures having different desirable features such as granularity, inclination, and randomness. The experimental evaluation shows that the random network provides good results, at a computational cost less than that of other approaches such as Markov random fields. Various examples of textures generated by our method are presented.
TWO-DIMENSIONAL UNIQUELY PARSABLE ISOMETRIC ARRAY GRAMMARS
Authors: YAMAMOTO YASUNORI , MORITA KENICHI
Published: November 2004

We propose a new subclass of two-dimensional isometric array grammar, called Uniquely Parsable Array Grammar (UPAG). UPAG is a grammar class such that when we parse (i.e. apply rewriting rules reversely to) a given two-dimensional word, the rewritable portions of the word do not overlap each other and the rule that is applicable to each portion is uniquely determined. Thus parsing can be done in a deterministic manner. We study basic properties of UPAG such as unique parsability and parallel parsability. Then we define Monotone Terminating UPAG (MTUPAG), a subclass of UPAG, and show that any two-dimensional word generated by MTUPAG can be parsed in linear time. We also show several examples of MTUPAGs which generate interesting sets of geometrical patterns.
A NEW APPROACH FOR FEATURE POINT CLASSIFICATION, AGGREGATION, AND DESCRIPTION
Authors: CHEN LING-HWEI
Published: November 2004

In this paper, an edge point, line point, or curve point is called a feature point. A new approach to extract junction points and to describe feature points is proposed here. It accepts as input data a binary image resulting from a feature detector without thinning. In the binary image, each black point is first classified based on the number of lines passing through it and on a local property that the classes of its neighboring points are almost the same. Next, an aggregation method is presented to group those classified points into several segments. The orientation of each segment is kept either clockwise or counterclockwise. Conic curves are then used to describe these segments. Finally, junction points including corner points, cross points, branch points, and inflection points are located. It is worth mentioning that the proposed method does not use any thinning process and curvature information. The effectiveness of the approach is also verified by one illustrative example and two experimental results.
SCALED AND SCALING-FREE McCLELLAN TRANSFORMATIONS FOR THE DESIGN OF 2-D DIGITAL FILTERS
Authors: NAGAMUTHU N. , SWAMY M. N. S.
Published: November 2004

In this paper, the scaling problem of McClellan transformation used for the design 2-D digital filters with elliptical and circular cutoff contours is critically analyzed. Several new and extremely simple formulas for calculating the maximum and minimum values of the transformation function are presented. Using these extreme values, simple formulas for scaling factors and scaled McClellan transformations are derived for the various cases of each type of contour. Using the necessary and sufficient conditions for a scaling-free transformation, the scaling-free McClellan transformations are also derived. It is shown that the number of independent coefficients in them to be optimized varies from 0 to 2 depending on the case, compared to 3 in the original transformation. They are very useful in deriving analytical expressions for the transformation coefficients, and the 2-D filters designed by employing them have a smaller number of multiplications per output sample and hence, attractive for real-time applications.

A new scaling formula is presented and some of its properties and effects on the derived formulas are discussed. The major advantage of this new formula is that from the unscaled transformation coefficients for a given type of 2-D filter, we can generate the scaled transformation coefficients for a different type of 2-D filter. Some examples are presented to demonstrate the usefulness of the derived formulas.
BASIN ORGANIZATION PRIOR TO A TANGLED SADDLE-NODE BIFURCATION
Authors: SOLIMAN MOHAMED S. , THOMPSON J. M. T.
Published: November 2004

Heteroclinic and homoclinic connections of saddle cycles play an important role in basin organization. In this study, we outline how these events can lead to an indeterminate jump to resonance from a saddle-node bifurcation. Here, due to the fractal structure of the basins in the vicinity of the saddle-node, we cannot predict to which available attractor the system will jump in the presence of even infinitesimal noise.
COMPUTATIONAL UNFOLDING OF DOUBLE-CUSP MODELS OF OPINION FORMATION
Authors: ABRAHAM RALPH , KEITH ALEXANDER , KOEBBE MATTHEW , MAYER-KRESS GOTTFRIED
Published: November 2004

In 1975, Isnard and Zeeman proposed a cusp catastrophe model for the polarization of a social group, such as the population of a democratic nation. Ten years later, Kadyrov combined two of these cusps into a model for the opinion dynamics of two "nonsocialist" nations. This is a nongradient dynamical system, more general than the double-cusp catastrophe studied by Callahan and Sashin [1987]. Here, we present a computational study of the nongradient double cusp, in which the degeneracy of Kadyrov's model is unfolded in codimension eight. Also, we develop a discrete-time cusp model, study the corresponding double cusp, establish its equivalence to the continuous-time double cusp, and discuss some potential applications. We find bifurcations for multiple critical-point attractors, periodic attractors, and (for the discrete case) bifurcations to quasiperiodic and chaotic attractors.
ITERATED ALGEBRAIC FUNCTIONS AND FUNCTIONAL EQUATIONS
Authors: MÜNZNER H. F. , RASCH H.-M.
Published: November 2004

This paper deals with the foundations of a theory of iterated algebraic functions. The results concern a modification of the shift space of all forward orbits, which one can get as a projective limit of Riemann surfaces. Our interest in this topic stems from computer experiments. The connection between the theory and these experiments is only sketched in the introduction.
THE FORMATION OF A RE-ENTRANT ACTION POTENTIAL WAVE FRONT IN TISSUE WITH UNEQUAL ANISOTROPY RATIOS
Authors: ROTH BRADLEY J. , SAYPOL JOSHUA M.
Published: November 2004

In a syncytial tissue, the intracellular and extracellular spaces may have different degrees of anisotropy. This property allows generation of a re-entrant wave front in a two-dimensional sheet of tissue after two successive stimuli are applied through the same electrode, if the second stimulus is delivered during the vulnerable phase of the first action potential. The re-entrant wave front contains four phase singularities placed symmetrically about the position of the electrode.
TRANSMISSION OF DIGITAL SIGNALS BY CHAOTIC SYNCHRONIZATION
Authors: PARLITZ U. , CHUA L.O. , KOCAREV Lj. , HALLE K.S. , SHANG A.
Published: November 2004

The transmission of digital signals by means of chaotic synchronization is demonstrated, numerically as well as experimentally, via Chua’s circuit.
TRANSOBJ: SOFTWARE PROTOTYPING ENVIRONMENT FOR REAL-TIME TRANSACTION-BASED SOFTWARE SYSTEM APPLICATIONS
Authors: ITOH KIYOSHI , TAMURA YASUHISA , HONIDEN SHINICHI
Published: November 2004

A software prototyping environment called TransObj (TRANSaction and OBJect) is used for designing real-time Transaction-based Concurrent Software Systems (TCSS). In a TCSS design process, a software designer should perform both functional design and performance design. The designer should change his design view from a transaction-based paradigm to an object-based paradigm during the TCSS design process. Recognition of re-entrant functional objects and serially reusable functional objects in the TCSS should be required. TransObj includes the Stepwise Prototyping Method (SPM), and two SPM-based tools: Prolog-based TransObj (P-TransObj) and GPSS-based TransObj (G-TransObj). SPM enables the designer to advance both functional design and performance design for the TCSS prototype as controling the change of design view paradigms. P-TransObj mainly checks the prototype in a microscopic view on a personal computer. G-TransObj mainly checks the same prototype with a longer time span on a large-scale computer.