Showing papers in "Progress of Theoretical Physics in 1986"

Large Scale Quantum Fluctuations in the Inflationary Universe

Abstract: Quantum fluctuations of an inflation-driving scalar field are evaluated in a way manifestly independent of the choice of coordinate gauge conditions. It is found that the dynamical degree of freedom of the fluctuating field is represented in terms of a nearly massless conformal scalar field in the unperturbed de Sitter background. Implications of the result are discussed. In particular, it is argued that classical cosmological density perturbations may not be generated in the sense as discussed in the literature.

A Soluble Active Rotater Model Showing Phase Transitions via Mutual Entertainment

Abstract: Some analytical results are obtained for a large population of limit·cycle oscillators modelled by a set of deterministic equations 1>i = WiNK'2;/j~lsin(

Vacuum Energies of String Compactified on Torus

Abstract: Computation of the one-loop vacuum energy is attempted for closed bosonic string compactified on various tori. Modular invariance of the one-loop vacuum energy is shown. The divergent tachyon contribution forces us to employ a subtraction prescription. For one-dimensional torus, the affine Kac-Moody algebra for SU(2)×SU(2) is realized at the absolute minimum of the vacuum energy. For general r-dimensional torus, the algebra for [SU(2)×SU(2)]^r is found to be an unstable saddle point. A detailed study of r=2 case shows that SU(3)×SU(3) has the lowest vacuum energy.

Phase transitions in active rotator systems

Abstract: On introduit un modele de rotateur actif afin d'etudier la dynamique statistique d'une grande population d'oscillateurs a cycle limite ou d'elements excitables. Ceci se definit dynamiquement comme une version stochastique d'un modele planaire relaxationnel modifiee par une force constante additionnelle

Fermi Liquid Theory on the Basis of the Periodic Anderson Hamiltonian

Abstract: T-linear term of specific heat and magnetic susceptibility at zero temperature are derived for the heavy eleCtron systems, and relations among these quantities are discussed on the basis of the Fermi liquid theory. Further, a rigorous expression of the T2-term of resistivity at low temperatures is also obtained on the basis of Kubo formula. It is shown that the coefficient of the T2-term arising from the electron interaction is strongly enhanced though it vanishes because of the momentum conservation for a free electron system possessing no crystal lattice.

A polar state in a slab as a soluble model of p-wave Fermi superfluid in finite geometry

Abstract: Modele de l'effet dimensionnel, avec un parametre d'ordre perpendiculaire a la paroi, de forme essentiellement identique a celle du reseau solitons du polyacetylene, representant une solution analytique autocoherente de l'equation de la bande interdite

Stability Theory of Synchronized Motion in Coupled-Oscillator Systems. IV ---Instability of Synchronized Chaos and New Intermittency---

Abstract: On etudie un systeme a chaos couples constitue de deux sous-systemes immediatement apres le point d'instabilite des chaos synchronises. Le systeme exhibe deux types d'intermittance

Can the Membrane Be a Unification Model

Abstract: On etudie quand un modele de membrane peut engendrer des particules sans masse dans le spectre en calculant l'energie de Casimir

Gauge invariant local action of string field from BRS formalism

Abstract: A systematic prescription is given to find the "original" gauge-invariant string field Lagrangian from Siegel's gauge-fixed Lagrangian containing an infinite tower of ghosts' ghosts. A local and gauge­ invariant Lagrangian of free bosonic string field is constructed in a complete form by this method. It reproduces Neveu and West's result up to the sixth excited level order. We also discuss the extension of the BRS formalism to the interacting string field theory and give the unitarity proof of such class of theories.

Curvature Invariants of Random Interface Generated by Gaussian Fields

Abstract: On considere des interfaces aleatoires engendrees par des intersections de niveaux d'un champ aleatoire gaussien

Intermittency Caused by Chaotic Modulation. II ---Lyapunov Exponent, Fractal Structure and Power Spectrum---

Abstract: On etudie un systeme application sous une modulation chaotique, qui a le point fixe, independamment du parametre de controle et de modulation

Localization Length and Inverse Participation Ratio of Two Dimensional Electron in the Quantized Hall Effect

Abstract: Calcul du rapport de participation inverse pour le niveau de Landau ZD le plus bas en presence d'un potentiel aleatoire gaussien et estimation de l'exposant critique de la longueur de localisation au voisinage du centre de bande

Vibron Solitons and Soliton-Induced Infrared Spectra of Crystalline Acetanilide

Abstract: Application de la theorie de solitons vibroniques, developpee recemment par l'auteur, a l'interpretation de la bande amide I, deplacee vers le rouge, qui a ete observee dans le spectre de l'acetanilide. Determination de la frequence propre des solitons stationnaires par resolution approchee d'une equation aux valeurs propres non lineaire

Supersymmetric Non-Linear Lagrangians of Kählerian Coset Spaces G/H: G=E6, E7 and E8

Abstract: On donne une procedure simple et generale pour construire explicitement un lagrangien de modele sigma non lineaire supersymetrique pour un espace co-ensemble kahlerien G/H. On considere les varietes G/H=E 7 /SU(5)×SU(3)×U(1) et E 8 /SO(10)×SU(3)×U(1)

Motion of a Shell at Metric Junction

Abstract: On etudie le mouvement de la coque spherique aux jonctions metriques entre les metriques de Minkowski, Schwarzschild et De Sitter a la fois pour une coque de poussiere et pour une coque a energie vide

Global Spectral Characterization of Chaotic Dynamics

Abstract: On propose une nouvelle caracterisation globale de la dynamique chaotique. Elle donne une description unifiee de certains aspects du chaos

Statistical Properties of Random Interface System

Abstract: StatisticaJ properties of binary phase system with semi-macroscopic random interfaces are studied. Singularity and symmetry of the correlation function are discussed in the case of smooth interface. Characteristic length scales,are defined by using the interface statistics. The existence of the equivalent sphere system is shown for the non-spherical irregular droplet. The irregularity of simple droplets is characterized by an inequality related to the topological invariant. It is shown that statistically self­ complementary, smooth system is mutually percolating. As a statistical foundation of the random interface problem, the relations to the theory of excursion set of random field are discussed. The expression of area density of the boundary set is obtained for the Gaussian field in Euclidean space with arbitrary dimension d. The cross-over phenomena in the spinodal decomposition process is also discussed using the statistical analyses on the interface.

On p-Wave Pairing Superconductivity under Hexagonal and Tetragonal Symmetries

Abstract: Recently much attention has been focused on heavy electron systems l ) such as UBeI3, UPta and CeCu2Siz. One of the most controvertial points is the nature of the superconductivity: Whether it is a convensional singlet pairing or triplet pairing. Volovik and Gor'kov;) Ueda and Rice,3) and Bloune) have discussed non-trivial pairing super­ conducting states under certain crystal-field symmetries whenthe spin-orbit coupling is strong. In particular, Volovik and Gor'kov 2 ) have listed all possible states for both triplet and singlet pairings in the systems with cubic ( 0), hexagonal (D6 ) and tetragonal (D.) symmetries. They2)-.) all agree that there is no triplet pairing states in which the energy gap vanishes on lines of the Fermi surface. In an earlier paper 5 ) (referred to as 1) we have

The Recovery of the Chiral Symmetry in Lattice Gross-Neveu Model

Abstract: The recovery of the chiral symmetry is carefully analyzed in the lattice Gross·Neveu model with Wilson's fermion, by using the effective potential obtained in the large N limit. It turns out that we have to introduce two bare coupling constants for four· fermi interactions as well as the bare mass term in order to obtain the chiral symmetric theory in the continuum limit. A method is proposed to extract the genuine order parameter that scales in the continuum limit. .

The Dynamical Stability of a Fat Disk with Constant Specific Angular Momentum

Abstract: On etudie la stabilite de tores en rotation, stationnaires, axisymetriques de moment angulaire specifique constant et d'entropie uniforme. A l'aide d'une equation de perturbation linearisee, on resout numeriquement le probleme aux valeurs propres a 2 dimensions. On trouve que de tels tores sont instables

Cooperative Phenomena in Two-Dimensional Active Rotator Systems

Abstract: Phase transitions of active rotator systems with short-range coupling are discussed. The constituents of the system which we call active rotators are represented by a phase model of a limit-cycle oscillator or an excitable element, i.e., dt/J/dt = w-bsint/J, (Iw/bl

Monte Carlo Simulation of Quantum Heisenberg Magnets on the Triangular Lattice

Abstract: 2) a systematic method for Monte Carlo simulation of quantum systems. There have been reported many studies using this method to investigate various quantum systems. 3 ) The essence of the method is to approximate the partition function with the use of the generalized Trotter formula exp(-S$C)~[ITexp (-SJljn)]n, (1) j

Covariant Quantization of Neveu-Schwarz-Ramond Model

Abstract: On presente une quantification manifestement covariante des modeles de Neveu-Schwarz et de Ramond en utilisant l'invariance BRS. On determine la dimension critique de chaque modele. On demontre le theoreme de non-fantome