Zitterbewegung by Quantum Field Theory Considerations

The validity of the work by Lamata et al [Phys. Rev. Lett. 98, 253005 (2007)] can be further shown by quantum field theory considerations.Comment: 5 pages, no figure, to be published in Physical Review

Multipole polarizability of a graded spherical particle

We have studied the multipole polarizability of a graded spherical particle in a nonuniform electric field, in which the conductivity can vary radially inside the particle. The main objective of this work is to access the effects of multipole interactions at small interparticle separations, which can be important in non-dilute suspensions of functionally graded materials. The nonuniform electric field arises either from that applied on the particle or from the local field of all other particles. We developed a differential effective multipole moment approximation (DEMMA) to compute the multipole moment of a graded spherical particle in a nonuniform external field. Moreover, we compare the DEMMA results with the exact results of the power-law graded profile and the agreement is excellent. The extension to anisotropic DEMMA will be studied in an Appendix.Comment: LaTeX format, 2 eps figures, submitted for publication

Soliton solution of continuum magnetization-equation in conducting ferromagnet with a spin-polarized current

Exact soliton solutions of a modified Landau-Lifshitz equation for the magnetization of conducting ferromagnet in the presence of a spin-polarized current are obtained by means of inverse scattering transformation. From the analytical solution effects of spin-current on the frequency, wave number, and dispersion law of spin wave are investigated. The one-soliton solution indicates obviously current-driven precession and periodic shape-variation as well. The inelastic collision of solitons by which we mean the shape change before and after collision appears due to the spin current. We, moreover, show that complete inelastic collisions can be achieved by adjusting spectrum and current parameters. This may lead to a potential technique for shape control of spin wave.Comment: 8 pages, 2 figure

HOUSEHOLD SIZE AND COMPOSITION IMPACTS ON MEAT DEMAND IN MEXICO: A CENSORED DEMAND SYSTEM APPROACH

The proposed paper adopts the censored demand system approach of Lee and Pitt (1986) to examine the structure of Mexican food demand. This approach uses the concept of virtual prices to explain specific purchase patterns. The contribution of our selected paper is the incorporation of the endogenous equivalence scale function proposed by Phlipps (1998) within this censored system. The contribution of this analysis is not only in terms of the use of an endogenous scaling function within a censored demand system, but we also will be use simulated maximum likelihood techniques which allows for the specification and estimation of significantly larger sized demand systems without the imposition of restrictive distributional assumptions on the equation error terms. We use a Gibbs sampling techniques to evaluate higher order truncated distributions required to implement the Lee and Pitt (1986) model specification.Demand and Price Analysis,