Decoherence, pointer engineering and quantum state protection

We present a proposal for protecting states against decoherence, based on the engineering of pointer states. We apply this procedure to the vibrational motion of a trapped ion, and show how to protect qubits, squeezed states, approximate phase eigenstates and superpositions of coherent states.Comment: 1 figur

Quintessence and Scalar Dark Matter in the Universe

Continuing with previous works, we present a cosmological model in which dark matter and dark energy are modeled by scalar fields $\Phi$ and $\Psi$, respectively, endowed with the scalar potentials $V(\Phi)=V_{o}[ \cosh {(\lambda \sqrt{\kappa_{o}}\Phi)}-1]$ and $\tilde{V}(\Psi)=\tilde{V_{o}}[ \sinh {(\alpha \sqrt{\kappa_{o}}\Psi)}] ^{\beta}$. This model contains 95% of scalar field. We obtain that the scalar dark matter mass is $m_{\Phi}\sim 10^{-26}eV.$ The solution obtained allows us to recover the success of the standard CDM. The implications on the formation of structure are reviewed. We obtain that the minimal cutoff radio for this model is $r_{c}\sim 1.2 kpc.$Comment: 4 pages REVTeX, 3 eps color figures. Minor changes and references updated. To appear in Classical and Quantum Gravity as a Letter to the Editor. More information at http://www.fis.cinvestav.mx/~siddh/PHI

Single observable concurrence measurement without simultaneous copies

We present a protocol that allows us to obtain the concurrence of any two qubit pure state by performing a minimal and optimal tomography of one of the subsystems through measuring a single observable of an ancillary four dimensional qudit. An implementation for a system of trapped ions is also proposed, which can be achieved with present day experimental techniques.Comment: 4 pages, 1 figur

Dados portugueses para o estudo dos salários na Índia: Cananor, 1516-1517

This essay discusses new evidence for wage developments in Western India from c. 1300 to 1600. By introducing wage and price data for Kannur (Cananor in Portuguese and British sources) for the years 1516-1517 we contribute to a larger discussion about standards of living in South Asia. These figures from unpublished Portuguese archival sources are compared to Indian ones for the early fourteenth and late sixteenth centuries (no other being available so far). We conclude that the overall purchasing power of wage earners in Kannur in 1516-1517 was not substantially lower than in Delhi 1311. This suggests that real wages remained stable at a low level in the fourteenth and fifteenth centuries, then rose during the sixteenth century to an all-time high around 1600, before dropping again (if expressed in grain), though never returning to the low levels of 1300-1500.info:eu-repo/semantics/publishedVersio

Key Phrase Extraction of Lightly Filtered Broadcast News

This paper explores the impact of light filtering on automatic key phrase extraction (AKE) applied to Broadcast News (BN). Key phrases are words and expressions that best characterize the content of a document. Key phrases are often used to index the document or as features in further processing. This makes improvements in AKE accuracy particularly important. We hypothesized that filtering out marginally relevant sentences from a document would improve AKE accuracy. Our experiments confirmed this hypothesis. Elimination of as little as 10% of the document sentences lead to a 2% improvement in AKE precision and recall. AKE is built over MAUI toolkit that follows a supervised learning approach. We trained and tested our AKE method on a gold standard made of 8 BN programs containing 110 manually annotated news stories. The experiments were conducted within a Multimedia Monitoring Solution (MMS) system for TV and radio news/programs, running daily, and monitoring 12 TV and 4 radio channels.Comment: In 15th International Conference on Text, Speech and Dialogue (TSD 2012

Produção de mudas de abacaxi variedade BRS Imperial em função de tipos de seccionamento de talo.

A produção de mudas de qualidade fitossanitária de abacaxi é um grande gargalo para a expansão e crescimento da área produtiva desta cultura no país, principalmente para variedades novas. A propagação do abacaxizeiro se faz exclusivamente de forma vegetativa, ou seja, as mudas utilizadas no novo plantio são provenientes do cultivo anterior