Atomic Focusing by Quantum Fields: Entanglement Properties

The coherent manipulation of the atomic matter waves is of great interest both in science and technology. In order to study how an atom optic device alters the coherence of an atomic beam, we consider the quantum lens proposed by Averbukh et al [1] to show the discrete nature of the electromagnetic field. We extend the analysis of this quantum lens to the study of another essentially quantum property present in the focusing process, i.e., the atom-field entanglement, and show how the initial atomic coherence and purity are affected by the entanglement. The dynamics of this process is obtained in closed form. We calculate the beam quality factor and the trace of the square of the reduced density matrix as a function of the average photon number in order to analyze the coherence and purity of the atomic beam during the focusing process.Comment: 10 pages, 4 figure

Plants used by chimpanzees and humans in Cantanhez, Guinea-Bissau. Field guide

This is the final version. Available from LAE/CRIA via the link in this recordThe Portuguese version of this field guide is available in ORE: http://hdl.handle.net/10871/121034FC

Plants used by chimpanzees and humans in Cantanhez, Guinea-Bissau. Field guide

This is the final version. Available from LAE/CRIA via the link in this recordThe Portuguese version of this field guide is available in ORE: http://hdl.handle.net/10871/121034FC

Crystallization and preliminary crystallographic studies of FoxE from Rhodobacter ferrooxidans SW2, an FeII oxidoreductase involved in photoferrotrophy

FoxE is a protein encoded by the foxEYZ operon of Rhodobacter ferrooxidans SW2 that is involved in Fe^II-based anoxygenic photosynthesis (`photoferrotrophy'). It is thought to reside in the periplasm, where it stimulates light-dependent Fe^II oxidation. It contains 259 residues, including two haem c-binding motifs. As no three-dimensional model is available and there is no structure with a similar sequence, crystals of FoxE were produced. They diffracted to 2.44 Å resolution using synchrotron radiation at the Fe edge. The phase problem was solved by SAD using SHELXC/D/E and the experimental maps confirmed the presence of two haems per molecule

Strain sensitivity enhancement in suspended core fiber tapers

Suspended core fiber tapers with different cross sections (with diameters from 70 μm to 120 μm) are produced by filament heating. Before obtaining the taper, the spectral behavior of the suspended core fiber is a multimode interference structure. When the taper is made, an intermodal interference between a few modes is observed. This effect is clearly visible for low taper core dimensions. Since the core and cladding do not collapse, two taper regions exist, one in the core and the other in the cladding. The cladding taper does not affect the light transmission, only the core is reduced to a microtaper. The spectral response of the microtaper based-suspended core fiber is similar to a beat of two interferometers. The strain is applied to the microtaper, and with the reduction in the transverse area, an increase in sensitivity is observed. When the taper is immersed in a liquid with a different index of refraction or subjected to temperature variations, no spectral change occurs

Pimenta longa: nutrição, calagem e adubação.

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Escarificação mecânica e embebição na germinação de sementes de castanha-do-brasil.

bitstream/item/28826/1/CPATU-BP10.pd