Quantum state of a free spin-1/2 particle and the inextricable dependence of spin and momentum under Lorentz transformations

We revise the Dirac equation for a free particle and investigate Lorentz transformations on spinors. We study how the spin quantization axis changes under Lorentz transformations, and evince the interplay between spin and momentum in this context.Comment: 14 pages, 3 figures, published as a Review in the IJQ

Composição florística e fauna associada das ilhas flutuantes livres, Rio Paraguai, Corumbá, MS.

As ilhas flutuantes livres englobam várias espécies vegetais tais como camalotes e gramíneas. Nas folhas e raízes destas plantas encontra-se uma diversidade de organismos. Este trabalho teve como objetivo fazer o levantamento das espécies vegetais componentes das ilhas flutuantes livres e conhecer os organismos associados e seus hábitos alimentares. Free floating islands include several species such as water hyacinth and grasses. In leaves and roots of these plants there are a diversity of organisms. This study aimed to survey the plant species of these free floating islands and recognize the associated organisms and its food habits

Eficiência alimentar de rações com diferentes níveis proteicos para o peixe ornamental Colisa lalia.

Objetivando conhecer o melhor nível proteico para terminação do crescimento de colisa-lalia, utilizou-se cinco tratamentos com cinco repetições em delineamento inteiramente casualizado. Cada unidade experimental compreendia a média de características mensuradas em seis peixes.Organizado por: Sílvio Ricardo Maurano; AQUACIÊNCIA 2012

Experimental implementation of a NMR entanglement witness

Entanglement witnesses (EW) allow the detection of entanglement in a quantum system, from the measurement of some few observables. They do not require the complete determination of the quantum state, which is regarded as a main advantage. On this paper it is experimentally analyzed an entanglement witness recently proposed in the context of Nuclear Magnetic Resonance (NMR) experiments to test it in some Bell-diagonal states. We also propose some optimal entanglement witness for Bell-diagonal states. The efficiency of the two types of EW's are compared to a measure of entanglement with tomographic cost, the generalized robustness of entanglement. It is used a GRAPE algorithm to produce an entangled state which is out of the detection region of the EW for Bell-diagonal states. Upon relaxation, the results show that there is a region in which both EW fails, whereas the generalized robustness still shows entanglement, but with the entanglement witness proposed here with a better performance