Aplicação de uma língua electrónica na classificação de méis monoflorais

Analisou-se o perfil polínico de 51 amostras de mel nacional. Os pólens mais frequentes no mel são originários das plantas dos géneros Lavandula, Cistus, Echium, Erica, Castanea, Thymus, Prunus, Cytisus, Carduus, Trifolium e Citrus. Considerando a classificação de mel monofloral de Lavandula (pólen predominante superior a 15%), de Erica e de Echium (pólen predominante superior a 45%) seleccionaram-se 38 méis monoflorais: 18, 9 e 11 destes méis foram classificados como méis monoflorais de Lavandula, Erica e Echium, respectivamente. Contudo há méis que podem ser classificados como mel monofloral de dois géneros de pólen (Lavandula-Echium, Erica-Lavandula, Echium-Lavandula). Os méis monoflorais foram analisados com um sistema de multi-sensores químicos não específicos de sensibilidade cruzada (Língua Electrónica) e os resultados foram tratados através da análise de componentes principais e análise discriminante. Verificou-se que é possível discriminar razoavelmente o mel monofloral de acordo com o género do pólen predominante

Mixed quantum state detection with inconclusive results

We consider the problem of designing an optimal quantum detector with a fixed rate of inconclusive results that maximizes the probability of correct detection, when distinguishing between a collection of mixed quantum states. We develop a sufficient condition for the scaled inverse measurement to maximize the probability of correct detection for the case in which the rate of inconclusive results exceeds a certain threshold. Using this condition we derive the optimal measurement for linearly independent pure-state sets, and for mixed-state sets with a broad class of symmetries. Specifically, we consider geometrically uniform (GU) state sets and compound geometrically uniform (CGU) state sets with generators that satisfy a certain constraint. We then show that the optimal measurements corresponding to GU and CGU state sets with arbitrary generators are also GU and CGU respectively, with generators that can be computed very efficiently in polynomial time within any desired accuracy by solving a semidefinite programming problem.Comment: Submitted to Phys. Rev.

Some Properties of the Computable Cross Norm Criterion for Separability

The computable cross norm (CCN) criterion is a new powerful analytical and computable separability criterion for bipartite quantum states, that is also known to systematically detect bound entanglement. In certain aspects this criterion complements the well-known Peres positive partial transpose (PPT) criterion. In the present paper we study important analytical properties of the CCN criterion. We show that in contrast to the PPT criterion it is not sufficient in dimension 2 x 2. In higher dimensions we prove theorems connecting the fidelity of a quantum state with the CCN criterion. We also analyze the behaviour of the CCN criterion under local operations and identify the operations that leave it invariant. It turns out that the CCN criterion is in general not invariant under local operations.Comment: 7 pages; accepted by Physical Review A; error in Appendix B correcte

Azeite ‘Galega Vulgar’: evolução sensorial durante a maturação na campanha 2000/01

Comunicação apresentada no III Simpósio Nacional de Olivicultura que decorreu em Castelo Branco, na Escola Superior Agrária do Instituto Politécnico de Castelo Branco, de 29 a 31 de Outubro de 2003.O presente trabalho teve por objectivo estudar as características cromáticas, os teores em pigmentos e o sabor amargo (K225) do azeite monovarietal da ‘Galega Vulgar’, durante a maturação, na campanha 2000/01. Verificou-se que a pureza óptica e o sabor amargo decresceram linearmente com o índice de maturação. Os teores de feofitina a, de ß-caroteno e de luteína decresceram também com o índice de maturação, mas de forma exponencial

Constructing Entanglement Witness Via Real Skew-Symmetric Operators

In this work, new types of EWs are introduced. They are constructed by using real skew-symmetric operators defined on a single party subsystem of a bipartite dxd system and a maximal entangled state in that system. A canonical form for these witnesses is proposed which is called canonical EW in corresponding to canonical real skew-symmetric operator. Also for each possible partition of the canonical real skew-symmetric operator corresponding EW is obtained. The method used for dxd case is extended to d1xd2 systems. It is shown that there exist Cd2xd1 distinct possibilities to construct EWs for a given d1xd2 Hilbert space. The optimality and nd-optimality problem is studied for each type of EWs. In each step, a large class of quantum PPT states is introduced. It is shown that among them there exist entangled PPT states which are detected by the constructed witnesses. Also the idea of canonical EWs is extended to obtain other EWs with greater PPT entanglement detection power.Comment: 40 page

Microwave dielectric permittivity and photoluminescence of Eu 2O3 doped laser heated pedestal growth Ta 2O5 fibers

Partilhar documento na coleção da comunidade Laboratório Associado I3NWe report the microwave dielectric properties and photoluminescence of undoped and europium oxide doped Ta2O5 fibers, grown by laser heated pedestal growth technique. The effects of Eu2O3 doping 1–3 mol % on the structural, optical, and dielectric properties were investigated. At a frequency of 5 GHz, the undoped material exhibits a dielectric permittivity of 21 and for Eu2O3 doped Ta2O5 samples it increases, reaching up to 36 for the highest doping concentration. Nevertheless, the dielectric losses maintain a very low value. For this wide band gap oxide, Eu3+ optical activation was achieved and the emission is observed up to room temperature. Thus, the transparency and high permittivity make this material promising for electronic devices and microwave applications. © 2008 American Institute of Physics.FCT-PTDC/FIS/66262/06FCT-PTDC/CTM/66195/200

Removal of a single photon by adaptive absorption

We present a method to remove, using only linear optics, exactly one photon from a field-mode. This is achieved by putting the system in contact with an absorbing environment which is under continuous monitoring. A feedback mechanism then decouples the system from the environment as soon as the first photon is absorbed. We propose a possible scheme to implement this process and provide the theoretical tools to describe it

Implications of quantum automata for contextuality

We construct zero-error quantum finite automata (QFAs) for promise problems which cannot be solved by bounded-error probabilistic finite automata (PFAs). Here is a summary of our results: - There is a promise problem solvable by an exact two-way QFA in exponential expected time, but not by any bounded-error sublogarithmic space probabilistic Turing machine (PTM). - There is a promise problem solvable by an exact two-way QFA in quadratic expected time, but not by any bounded-error $o(\log \log n)$-space PTMs in polynomial expected time. The same problem can be solvable by a one-way Las Vegas (or exact two-way) QFA with quantum head in linear (expected) time. - There is a promise problem solvable by a Las Vegas realtime QFA, but not by any bounded-error realtime PFA. The same problem can be solvable by an exact two-way QFA in linear expected time but not by any exact two-way PFA. - There is a family of promise problems such that each promise problem can be solvable by a two-state exact realtime QFAs, but, there is no such bound on the number of states of realtime bounded-error PFAs solving the members this family. Our results imply that there exist zero-error quantum computational devices with a \emph{single qubit} of memory that cannot be simulated by any finite memory classical computational model. This provides a computational perspective on results regarding ontological theories of quantum mechanics \cite{Hardy04}, \cite{Montina08}. As a consequence we find that classical automata based simulation models \cite{Kleinmann11}, \cite{Blasiak13} are not sufficiently powerful to simulate quantum contextuality. We conclude by highlighting the interplay between results from automata models and their application to developing a general framework for quantum contextuality.Comment: 22 page