Search results for "Mathematical physics"
showing 10 items of 2687 documents
Automorphism Groups of Certain Rational Hypersurfaces in Complex Four-Space
2014
The Russell cubic is a smooth contractible affine complex threefold which is not isomorphic to affine three-space. In previous articles, we discussed the structure of the automorphism group of this variety. Here we review some consequences of this structure and generalize some results to other hypersurfaces which arise as deformations of Koras–Russell threefolds.
Quotients of the Dwork Pencil
2012
In this paper we investigate the geometry of the Dwork pencil in any dimension. More specifically, we study the automorphism group G of the generic fiber of the pencil over the complex projective line, and the quotients of it by various subgroups of G. In particular, we compute the Hodge numbers of these quotients via orbifold cohomology.
Groups acting freely on Calabi-Yau threefolds embedded in a product of del Pezzo surfaces
2011
In this paper, we investigate quotients of Calabi-Yau manifolds $Y$ embedded in Fano varieties $X$, which are products of two del Pezzo surfaces — with respect to groups $G$ that act freely on $Y$. In particular, we revisit some known examples and we obtain some new Calabi-Yau varieties with small Hodge numbers. The groups $G$ are subgroups of the automorphism groups of $X$, which is described in terms of the automorphism group of the two del Pezzo surfaces.
Representable and Continuous Functionals on Banach Quasi *-Algebras
2017
In the study of locally convex quasi *-algebras an important role is played by representable linear functionals; i.e., functionals which allow a GNS-construction. This paper is mainly devoted to the study of the continuity of representable functionals in Banach and Hilbert quasi *-algebras. Some other concepts related to representable functionals (full-representability, *-semisimplicity, etc) are revisited in these special cases. In particular, in the case of Hilbert quasi *-algebras, which are shown to be fully representable, the existence of a 1-1 correspondence between positive, bounded elements (defined in an appropriate way) and continuous representable functionals is proved.
The role of the $\Delta(1232)$-resonance in covariant baryon chiral perturbation theory
2013
We stress, on theoretical and phenomenological grounds, the importance of the $\Delta(1232)$-resonance in a chiral effective field theory approach applied to the study of $\pi N$ scattering. We show how its inclusion as a dynamical degree of freedom allow us to obtain reliably valuable information from $\pi N$ scattering data.
Chiral coupled channel dynamics of theΛ(1520)and theK−p→π0π0Λreaction
2005
We study the $\ensuremath{\Lambda}(1520){D}_{03}$ in a chiral coupled channel approach. This resonance appears to be dynamically generated from the interaction of the decuplet of baryons and the octet of mesons in s wave, and its treatment is improved here with the phenomenological inclusion of the $\overline{K}N$ and $\ensuremath{\pi}\ensuremath{\Sigma}$ channels in d wave. Since the most important building block in $\ensuremath{\Lambda}(1520)$ is the $\ensuremath{\pi}{\ensuremath{\Sigma}}^{*}(1385){P}_{13}$ channel, we study the ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}\ensuremath{\pi}{\ensuremath{\Sigma}}^{*}(1385)({\ensuremath{\pi}}^{0}\ensuremath{\Lambda})$ reaction in the region …
Limits to the fixed center approximation to Faddeev equations: The case of theϕ(2170)
2011
The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the $\ensuremath{\phi}(2170)$, which has been described by means of Faddeev equations as a resonant state of $\ensuremath{\phi}$ and $K\overline{K}$, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed.
Improved comparison of bar P and P charge-to-mass ratios
1995
The measured ratio of charge-to-mass ratios for the antiproton and proton is 1.000 000 001 5 ± 0.000 000 001 1. This 1 part in 109 comparison (1 ppb) is possible because a single or p is now directly observed while trapped in an open access Penning trap. The comparison is the most accurate mass spectrometry of particles with opposite charge and is the most sensitive test of CPT invariance for a baryon system. It is 40 times more accurate than our earlier comparison with many trapped antiprotons and protons, and is more than 45 000 times more accurate than earlier comparisons made with other techniques.
A bending theory of thermoelastic diffusion plates based on Green-Naghdi theory
2017
Abstract This article is concerned with bending plate theory for thermoelastic diffusion materials under Green-Naghdi theory. First, we present the basic equations which characterize the bending of thin thermoelastic diffusion plates for type II and III models. The theory allows for the effect of transverse shear deformation without any shear correction factor, and permits the propagation of waves at a finite speed without energy dissipation for type II model and with energy dissipation for type III model. By the semigroup theory of linear operators, we prove the well-posedness of the both models and the asymptotic behavior of the solutions of type III model. For unbounded plate of type III…
Equations-of-motion approach to the spin-12Ising model on the Bethe lattice
2006
We exactly solve the ferromagnetic spin- 1/2 Ising model on the Bethe lattice in the presence of an external magnetic field by means of the equations of motion method within the Green's function formalism. In particular, such an approach is applied to an isomorphic model of localized Fermi particles interacting via an intersite Coulomb interaction. A complete set of eigenoperators is found together with the corresponding eigenvalues. The Green's functions and the correlation functions are written in terms of a finite set of parameters to be self-consistently determined. A procedure is developed that allows us to exactly fix the unknown parameters in the case of a Bethe lattice with any coor…