A Robust Semidefinite Programming Approach to the Separability Problem

We express the optimization of entanglement witnesses for arbitrary bipartite states in terms of a class of convex optimization problems known as Robust Semidefinite Programs (RSDP). We propose, using well known properties of RSDP, several new sufficient tests for the separability of mixed states. Our results are then generalized to multipartite density operators.Comment: Revised version (minor spell corrections) . 6 pages; submitted to Physical Review

VILA DE PICINGUABA : O CASO DE UMA COMUNIDADE CAlÇARA NO INTERIOR DE UMA ÁREA PROTEGIDA

A Vila de Picinguaba no município de Ubatuba, Estado de São Paulo, está desde 1979 situada no interior do Parque Estadual da Serra do Mar, no denominado Núcleo Picinguaba. Este Núcleo tem aproximadamente 8.000 ha e é a única região do parque que chega até o mar. Originalmente, a vila era de pescadores artesanais, que detêm características culturais específicas. Nos últimos 15 anos, houve um processo de crescimento e transformação desta vila, o que vem descaracterizando a cultura local, ameaçando os objetivos de implantação do parque e degenerando a qualidade de vida de seus habitantes. Como retrato desta situação, temos hoje que 51,9% das edificações domiciliares são de propriedade de turistas. Para que houvesse 'tJma discussão conjunta, entre a população habitante da vila e o Instituto Florestal, das propostas de manejo para a área foram realizados dois diagnósticos (ambiental e de ocupação) e o seminário: "Vila de Picinguaba: Propostas para seu desenvolvimento e preservação" O trabalho aqui apresentado visa apontar as possibilidades de manejo desta área, considerando as finalidades conservacionistas de um parque estadual e a importância de se possibilitar a expressão de aspectos culturais tradicionais, ainda existentes no Estado de São Paulo

The violation of the Hund's rule in semiconductor artificial atoms

The unrestricted Pople-Nesbet approach for real atoms is adapted to quantum dots, the man-made artificial atoms, under applied magnetic field. Gaussian basis sets are used instead of the exact single-particle orbitals in the construction of the appropriated Slater determinants. Both system chemical potential and charging energy are calculated, as also the expected values for total and z-component in spin states. We have verified the validity of the energy shell structure as well as the Hund's rule state population at zero magnetic field. Above given fields, we have observed a violation of the Hund's rule by the suppression of triplets and quartets states at the 1p energy shell, taken as an example. We also compare our present results with those obtained using the LS-coupling scheme for low electronic occupations. We have focused our attention to ground-state properties for GaAs quantum dots populated up to forty electrons.Comment: 5 pages, 2 figures, submitted to Semic. Sci. Techno

Relativistic entanglement in single-particle quantum states using Non-Linear entanglement witnesses

In this study, the spin-momentum correlation of one massive spin-1/2 and spin-1 particle states, which are made based on projection of a relativistic spin operator into timelike direction is investigated. It is shown that by using Non-Linear entanglement witnesses (NLEWs), the effect of Lorentz transformation would decrease both the amount and the region of entanglement.Comment: 16 pages, 2 figures; to be published in Quantum Inf Process, 10.1007/s11128-011-0289-z (2011

Wannier-function description of the electronic polarization and infrared absorption of high-pressure hydrogen

We have constructed maximally-localized Wannier functions for prototype structures of solid molecular hydrogen under pressure, starting from LDA and tight-binding Bloch wave functions. Each occupied Wannier function can be associated with two paired protons, defining a ``Wannier molecule''. The sum of the dipole moments of these ``molecules'' always gives the correct macroscopic polarization, even under strong compression, when the overlap between nearby Wannier functions becomes significant. We find that at megabar pressures the contributions to the dipoles arising from the overlapping tails of the Wannier functions is very large. The strong vibron infrared absorption experimentally observed in phase III, above ~ 150 GPa, is analyzed in terms of the vibron-induced fluctuations of the Wannier dipoles. We decompose these fluctuations into ``static'' and ``dynamical'' contributions, and find that at such high densities the latter term, which increases much more steeply with pressure, is dominant.Comment: 17 pages, two-column style with 14 postscript figures embedded. Uses REVTEX and epsf macro

Recombinant proteins in plants.

Edição do Congress of the Brazilian Biotechnology Society, Florianópolis, 2013

Plasma Dynamics

Contains reports on four research projects.National Science Foundation (Grant GK-37979X)U.S. Atomic Energy Commission (Contract AT(11-1)-3070