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Teiji Kunihiro

Publications and source records attributed to Teiji Kunihiro.

114 records · Page 7Linked to original sources
arXiv1996

The Renormalization-Group Method Applied to Asymptotic Analysis of Vector Fields

The renormalization group method of Goldenfeld, Oono and their collaborators is applied to asymptotic analysis of vector fields. The method is formulated on the basis of the theory of envelopes, as was done for scalar fields. This formulation actually completes the discussion of the previous work for scalar equations. It is shown in a generic way that the method applied to equations with a bifurcation leads to the Landau-Stuart and the (time-dependent) Ginzburg-Landau equations. It is confirmed that this method is actually a powerful theory for the reduction of the dynamics as the reductive perturbation method is. Some examples for ordinary diferential equations, such as the forced Duffing, the Lotka-Volterra and the Lorenz equations, are worked out in this method: The time evolution of the solution of the Lotka-Volterra equation is explicitly given, while the center manifolds of the Lorenz equation are constructed in a simple way in the RG method.

hep-th↗
arXiv1996

Possible Production of the Sigma Meson in Nuclei

It should be a typical subject in this workshop to explore possible change of hadron properties in association with that of QCD vacuum due to an environmental change. In this report, we first summarize what hadrons are expected to show such a change and how they do. Then we propose several experiments including the ones utilizing electron and photon beams for examining possible restoration of chiral symmetry in nuclei and the possible existence of the sigma meson. The experiments are based on the observation that the sigma meson may decrease the mass and the width along with the partial restoration of chiral symmetry in the medium.

nucl-th↗
arXiv1995

A Geometrical Formulation of the Renormalization Group Method for Global Analysis II: Partial Differential Equations

It is shown that the renormalization group (RG) method for global analysis can be formulated in the context of the classical theory of envelopes: Several examples from partial differential equations are analyzed. The amplitude equations which are usually derived by the reductive perturbation theory are shown to be naturally derived as the equations describing the envelopes of the local solutions obtained in the perturbation theory.

patt-sol↗
arXiv1995

CHIRAL SYMMETRY AND $U_A(1)$ ANOMALY IN AN EFFECTIVE THEORY OF QCD

We show on the basis of an effective theory of QCD that a wide variety of observables in the hadron world is governed by the chiral symmetry together with an interplay between the axial anomaly and the explicit symmetry breaking due to the current quark mass. We also discuss the nature of the chiral transition at finite temperature and related dynamical phenomena using the effective Lagrangian. Some phenomenological implications of the small vector coupling (``vector limit'') at high temperatures are suggested.

hep-ph↗
arXiv1995

Chiral Symmetry and Scalar Meson in Hadron and Nuclear Physics

After giving a short introduction to the Nambu-Jona-Lasinio model with an anomaly term, we show the importance of the scalar-scalar correlation in the low-energy hadron dynamics, which correlation may be summarized by a scalar-isoscalar meson, the sigma meson. The discussion is based on the chiral quark model with the sigma-meson degrees of freedom. Possible experiments are proposed to produce the elusive meson in a nucleus and detect it. In relation to a precursory soft mode for the chiral transition, the reason is clarified why the dynamic properties of the superconductor may be described by the diffusive time-dependent Ginzburg-Landau (TDGL) equation. We indicate the chiral symmetry plays a significant role also in nuclei; one may say that the stability of nuclei is due to the chiral symmetry of QCD.

hep-ph↗