Detection of Multiparticle Entanglement: Quantifying the Search for Symmetric Extensions

We provide quantitative bounds on the characterisation of multiparticle separable states by states that have locally symmetric extensions. The bounds are derived from two-particle bounds and relate to recent studies on quantum versions of de Finetti's theorem. We discuss algorithmic applications of our results, in particular a quasipolynomial-time algorithm to decide whether a multiparticle quantum state is separable or entangled (for constant number of particles and constant error in the LOCC or Frobenius norm). Our results provide a theoretical justification for the use of the Search for Symmetric Extensions as a practical test for multiparticle entanglement.Comment: 5 pages, 1 figur

The quantum one-time pad in the presence of an eavesdropper

A classical one-time pad allows two parties to send private messages over a public classical channel -- an eavesdropper who intercepts the communication learns nothing about the message. A quantum one-time pad is a shared quantum state which allows two parties to send private messages or private quantum states over a public quantum channel. If the eavesdropper intercepts the quantum communication she learns nothing about the message. In the classical case, a one-time pad can be created using shared and partially private correlations. Here we consider the quantum case in the presence of an eavesdropper, and find the single letter formula for the rate at which the two parties can send messages using a quantum one-time pad

Letter to the editor

info:eu-repo/semantics/publishedVersio

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

Mosaico de imagens de satélite do Pantanal no ano 2000.

O Pantanal devido a sua extensão e dificuldade de acesso representa um desafio para o desenvolvimento de atividades de produção e conservação da natureza. Nesse sentido as tecnologias de Sensoriamento Remoto podem contribuir muito para o conhecimento e manejo desse ecossistema. O presente trabalho apresenta o mosaico de imagens Landsat 7 ETM do ano 2000 do Pantanal, onde ao contrário dos demais produtos dessa natureza, apresenta uma maior precisão de posicionamento em função de um extenso trabalho de campo realizado para o georreferenciamento das imagens. Esse trabalho é o resultado da parceria entre a Embrapa Pantanal e a WWF Brasil e está disponível também na homepage da Embrapa Pantanal. Esperamos com essa iniciativa estar cumprindo com nosso objetivo de levar à comunidade informações sobre o Pantanal.bitstream/item/81191/1/DOC43.pd

Avaliação da formação de corpos lúteos acessórios e dosagem de progesterona em cabras da raça Saanen após o uso de hCG.

Avalia a formação de CLa e concentração plasmática de progesterona em decorrência da administração de hCG em cabras cinco dias após a última monta natural. Conclui-se que o tratamento com hCG 5 dias após a última MN induziu um efeito luteotrópico, e não a formação de CLa, antecipando o momento da ocorrência da elevação das concentração de progesterona plasmática. [Evaluation of formation of accessories corpora lutea and plasma progesterone concentration in Saanen goats treated with hCG]

Quantifying Quantum Correlations in Fermionic Systems using Witness Operators

We present a method to quantify quantum correlations in arbitrary systems of indistinguishable fermions using witness operators. The method associates the problem of finding the optimal entan- glement witness of a state with a class of problems known as semidefinite programs (SDPs), which can be solved efficiently with arbitrary accuracy. Based on these optimal witnesses, we introduce a measure of quantum correlations which has an interpretation analogous to the Generalized Robust- ness of entanglement. We also extend the notion of quantum discord to the case of indistinguishable fermions, and propose a geometric quantifier, which is compared to our entanglement measure. Our numerical results show a remarkable equivalence between the proposed Generalized Robustness and the Schliemann concurrence, which are equal for pure states. For mixed states, the Schliemann con- currence presents itself as an upper bound for the Generalized Robustness. The quantum discord is also found to be an upper bound for the entanglement.Comment: 7 pages, 6 figures, Accepted for publication in Quantum Information Processin

A New Genus And Species Of Euptychiina (lepidoptera: Nymphalidae: Satyrinae) From Southern Brazil.

This paper describes a new genus and a new species of Euptychiina from open grassland habitats (campos de cima da serra) in southern Brazil. The systematic position of this new taxon is discussed based on morphological and molecular data, and it is considered sister to Taydebis Freitas. Since the campos vegetation is considered endangered due to anthropogenic activities, this butterfly species deserves attention and should be included in future conservation plans for this biome.40231-