M. del Castillo-Mussot

1D Schrödinger equations with Coulomb-type potentials

We employ Laplace and Fourier transforms in momentum space to find the bound states of the 1D Schr?dinger equations with two different potentials; and . By performing inverse transforms we show that for the potential the solutions in real space reduce to those of the 1D hydrogen atom with eigenenergies proportional to with n integer. Analogously, we find that for the potential the eigenenergies are proportional to and the eigenfunctions can be expressed in terms of fractional derivatives. Taking into account that both potentials are singular (the potential is analytical and the potential is not), we analyse the nature of their bound states.

High energy levels of Wannier exciton for electron and hole spatially separated in adjacent 2D quantum layers

We analyze a Wannier-Mott exciton in which electron and hole are constrained to move in two separated and parallel 2D quantum layers. We assume that in the confinement direction z both electron and hole are in their respective groundstate of a harmonic potential. We find a ρ and Φ-dependent Schrodinger equation which allows us to calculate the higher exciton eigenenergies and eigenfunctions within the WKB approximation.

Induced Cultural Globalization by an External Vector Field in an Enhanced Axelrod Model

A new model is proposed, in the context of Axelrod’s model for the study of cultural dissemination, to include and external vector field (VF) which describes the effects of mass media on social systems. The VF acts over the whole system and it is characterized by two parameters: a non-null overlap with each agent in the society and a confidence value of its information. Beyond a threshold value of the confidence there is induced monocultural globalization of the system lined up with the VF. Below this value, the multicultural states are unstable and certain homogenization of the system is obtained in opposite line up according to that we have called negative publicity effect. Three regimes of behavior for the spread process of the VF information as a function of time are reported.

Induced Monoculture In Axelrod Model With Clever Mass Media

A new model is proposed, in the context of Axelrods model for the study of cultural dissemination, to include an external vector field (VF) which describes the effects of mass media on social systems. The VF acts over the whole system and it is characterized by two parameters: a nonnull overlap with each agent in the society and a confidence value of its information. Beyond a threshold value of the confidence, there is induced monocultural globalization of the system lined up with the VF. Below this value, the multicultural states are unstable and certain homogenization of the system is obtained in opposite line up according to that we have called negative publicity effect. Three regimes of behavior for the spread process of the VF information as a function of time are reported.

SOCIAL HIERARCHIES WITH AN ATTRACTIVE SITE DISTRIBUTION

We reinvestigate the model of Bonabeau et al.1 of self-organizing social hierarchies by including a distribution of attractive sites. Agents move randomly except in the case where an attractive site is located in its neighborhood. We find that the transition between an egalitarian society at low population density and a hierarchical one at high population density strongly depends on the distribution and percolation of the valuable sites. We also show how agent diffusivity is closely related to social hierarchy.

Surface plasmon effects on the optical reflectivity of adsorbed molecular multilayers

Abstract We calculate the change in optical reflectivity due to the presence of thin films formed by a few layers adsorbed in a metal using a discrete point-dipole model, and we compare our results with those of the usual Fresnel theory. We find a considerable enhancement of the differential reflectance near the surface-plasmon resonance frequency of the vacuum-metal interface. In the case of p -polarization, the contributions coming from the images of molecules lying closer to the metal can be singled out if the angle of incidence is chosen to be the Brewster angle of the vacuum overlayer interface.

Variation of tight-binding parameters near surfaces

Abstract Surface effects on the tight-binding parameters for electrons are examined in a very simple system that allows the analytical calculation of all the atomic integrals needed. In spite of the simplicity of the model various qualitative results are obtained. It is seen that the inclusion of electron-electron interaction is essential to characterize the variation of the tight-binding parameters near defects. Effects of surface relaxation are also modelled and useful conclusions are drawn.

Stark-ladder resonances in the propagation of electromagnetic surface waves

Abstract We generalize a previous work [Phys. Rev. Lett. 64, 1433 (1990)] on bulk electromagnetic Stark-ladder resonances to include also resonances formed by coupled surface plasmons with wavevectors outside the light cone. It is proposed that these new resonances may be observed experimentally by the attenuated total reflectance (ATR) method in appropriate metal-insulator superlattices.

Note on hydrodynamic models of spatially dispersive conductor boundaries

Abstract In hydrodynamic models of electron dynamics the additional boundary condition (ABC), required at the interface between a spatialy dispersive conductor and a local medium, is singled out by the set of ABCs imposed at the boundaries between non local conductors. We find the appropriate ABC at nonlocal-local conductor and nonlocal conductor-local insulator interfaces corresponding to several frequently used sets of ABCs.

Generation of cultural map of 81 societies with economic zones superimposed

There exists [1] a cultural map of 81 societies (countries), with economic zones superimposed, which reflects the responses to scores of questions, given by over 200,000 respondents in all continents in the period 1999-2002. This map is given in terms of the following twodimensions (2D); i) traditional authority vs. secular-rational authority and ii) survival values vs. self-expression values.We try to reproduce the main features of this empirical map by making use of a fuzzy linear space in which each of the vector coordinates represent selected variables such as degree of industrialization, political regime, gap between rich and poor, cultural and religious traditions, etc.