To discuss the possibility that the superconductivities in NaxCoO2·yH2O are induced by electron correlation, we investigate the possible pairing symmetry based on the single-band Hubbard model whose dispersion of the bare energy band is obtained using the band structure calculation of NaxCoO2·yH2O. The superconducting transition temperature is estimated by solving the Éliashberg equation. In th...

To discuss a possibility that the superconductivities in NaxCoO2·yH2O are induced by the electron correlation, we investigate the possible pairing symmetry based on the single-band Hubbard model whose dispersion of the bare energy band is obtained by using FLAPW-LDA band structure calculation of NaxCoO2·yH2O. The superconducting transition temperature is estimated by solving the Éliashberg equa...

To discuss the possibility that the superconductivities in NaxCoO2·yH2O are induced by electron correlation, we investigate the possible pairing symmetry based on the single-band Hubbard model whose dispersion of the bare energy band is obtained using the band structure calculation of NaxCoO2·yH2O. The superconducting transition temperature is estimated by solving the Éliashberg equation. In th...

The parameter imbedding method for the Fredholm equation converts it into an initial value problem in its parameter λ. We establish the method for general operator equations of the form [I + ˆ f (λ)]ψ = φ. It is particularly useful for studying spontaneous symmetry breaking problems, such as contained in the nonlinear Schwinger-Dyson equation.

We consider static spherically symmetric solutions of the Einstein equations with cosmological constant Λ coupled to the SU(2) Yang Mills equations. We prove that under relatively mild conditions, any solution can be continued back to the origin of spherical symmetry and that the qualitative behavior of the solutions near the origin does not depend on Λ.

In this paper we will find a continuous of periodic orbits passing near infinity for a class of polynomial vector fields in R3. We consider polynomial vector fields that are invariant under a symmetry with respect to a plane Σ and that possess a “generalized heteroclinic loop” formed by two singular points e+ and e at infinity and their invariant manifolds Γ and Λ. Γ is an invariant manifold of...

For K an abstract elementary class with amalgamation and no maximal models, we show that categoricity in a highenough cardinal implies structural properties such as the uniqueness of limit models and the existence of good frames. This improves several classical results of Shelah. Theorem 0.1. Let μ ≥ LS(K). If K is categorical in a λ ≥ i(2μ)+ , then: (1) Whenever M0,M1,M2 ∈ Kμ are such that M1 ...

We examine the radiative decays of the Λ(1405) to octet baryons, Λ(1405) → Λγ and Λ(1405) → Σ0γ. In the limit of SU(3) symmetry the decay rates for these two modes are related, and we compute the leading correction to the relation in chiral perturbation theory. Such measurements will allow the sign of the strong coupling gΛ∗ to be determined. The SU(3) violating radiative decay to the baryon de...

This paper studies relationships between the order reductions of ordinary differential equations derived by the existence of λ-symmetries, telescopic vector fields and some nonlocal symmetries obtained by embedding the equation in an auxiliary system. The results let us connect such nonlocal symmetries with approaches that had been previously introduced: the exponential vector fields and the λ-...

We discuss the fate of the axial U(1) symmetry in 2-flavor QCD at finite temperature, where the non-singlet chiral symmetry is restored. We first summarize the previous theoretical investigation on the relation between the eigenvalue density of the Dirac operator and the axial U(1) symmetry. We show that the eigenvalue density near the origin behaves as λ γ with γ > 2 in the chirally symmetric ...