Adiabatic creation of entangled states by a bichromatic field designed from the topology of the dressed eigenenergies

Preparation of entangled pairs of coupled two-state systems driven by a bichromatic external field is studied. We use a system of two coupled spin-1/2 that can be translated into a three-state ladder model whose intermediate state represents the entangled state. We show that this entangled state can be prepared in a robust way with appropriate fields. Their frequencies and envelopes are derived from the topological properties of the model.Comment: 10 pages, 9 figure

Scattering by rough surfaces with alpha-stable non-Gaussian height distribution

We study the electromagnetic scattering problem on a random rough surface when the height distribution of the profile belongs to the family of alpha-stable laws. This allows us to model peaks of very large amplitude that are not accounted for by the classical Gaussian scheme. For such probability distributions with infinite variance the usual roughness parameters such as the RMS height, the correlation length or the correlation function are irrelevant. We show, however, that these notions can be extended to the alpha-stable case and introduce a set of adapted roughness parameters that coincide with the classical quantities in the Gaussian case. Then we study the scattering problem on a stationary alpha-stable surface and compute the scattering coefficient under the first-order Kirchhoff and small-slope approximations. An analytical formula is given in the high-frequency limit, which generalizes the well-known geometrical optics approximation. Some numerical results are given and discussed

Electromagnetic Scattering From Multi-Scale Rough Surfaces

It is shown that the wavelet correlation dimension is a very relevant quantity for the characterization of rough surfaces by remote sensing means. First, the concept of correlation length is generalized to surfaces with wide power spectrum. Second, it is demonstrated that, in the framework of the small-perturbation theory, the wavelet correlation dimension can be retrieved from a knowledge of the backscattered cross section for a discrete set of frequencies. Rigorous numerical experiments confirm these predictions, and in the last section an experimental scheme for a straightforward derivation of the wavelet correlation dimension is proposed

Catálogo dos Erotylidae (Coleoptera) Neotropicais Catalogue of Neotropical Erotylidae (Coleoptera)

<abstract language="eng">The present catalog is an inventory of names proposed in Erotylidae (from family through subspecies) ocurring in the Neotropical Region, up to the present date (1988). It updates the nomenclature of included taxa, adds taxonomic units proposed after the Kuhnt's Genera Insectorum (Kuhnt, 1909) and includes abbreviated references to the literature, which are fully cited at the end of this catalogue. The systematic order follows Kuhnt, 1909, and afterwards, the position given to each taxa by the original author