Selective Control of the Symmetric Dicke Subspace in Trapped Ions

We propose a method of manipulating selectively the symmetric Dicke subspace in the internal degrees of freedom of N trapped ions. We show that the direct access to ionic-motional subspaces, based on a suitable tuning of motion-dependent AC Stark shifts, induces a two-level dynamics involving previously selected ionic Dicke states. In this manner, it is possible to produce, sequentially and unitarily, ionic Dicke states with increasing excitation number. Moreover, we propose a probabilistic technique to produce directly any ionic Dicke state assuming suitable initial conditions.Comment: 5 pages and 1 figure. New version with minor changes and added references. Accepted in Physical Review

Effective Quantum Dynamics of Interacting Systems with Inhomogeneous Coupling

We study the quantum dynamics of a single mode/particle interacting inhomogeneously with a large number of particles and introduce an effective approach to find the accessible Hilbert space where the dynamics takes place. Two relevant examples are given: the inhomogeneous Tavis-Cummings model (e.g., N atomic qubits coupled to a single cavity mode, or to a motional mode in trapped ions) and the inhomogeneous coupling of an electron spin to N nuclear spins in a quantum dot.Comment: 9 pages and 10 figures, new version, accepted in Physical Review

A search for new hot subdwarf stars by means of Virtual Observatory tools

Hot subdwarf stars are faint, blue objects, and are the main contributors to the far-UV excess observed in elliptical galaxies. They offer an excellent laboratory to study close and wide binary systems, and to scrutinize their interiors through asteroseismology, as some of them undergo stellar oscillations. However, their origins are still uncertain, and increasing the number of detections is crucial to undertake statistical studies. In this work, we aim at defining a strategy to find new, uncatalogued hot subdwarfs. Making use of Virtual Observatory tools we thoroughly search stellar catalogues to retrieve multi-colour photometry and astrometric information of a known sample of blue objects, including hot subdwarfs, white dwarfs, cataclysmic variables and main sequence OB stars. We define a procedure to discriminate among these spectral classes, particularly designed to obtain a hot subdwarf sample with a low contamination factor. In order to check the validity of the method, this procedure is then applied to two test sky regions: the Kepler FoV and to a test region of around (RA:225, DEC:5) deg. As a result, we obtained 38 hot subdwarf candidates, 23 of which had already a spectral classification. We have acquired spectroscopy for three other targets, and four additional ones have an available SDSS spectrum, which we used to determine their spectral type. A temperature estimate is provided for the candidates based on their spectral energy distribution, considering two-atmospheres fit for objects with clear infrared excess. Eventually, out of 30 candidates with spectral classification, 26 objects were confirmed to be hot subdwarfs, yielding a contamination factor of only 13%. The high rate of success demonstrates the validity of the proposed strategy to find new uncatalogued hot subdwarfs. An application of this method to the entire sky will be presented in a forthcoming work.Comment: 13 pages, 7 figure

Multipartite Entanglement Generation Assisted by Inhomogeneous Coupling

We show that controllable inhomogeneous coupling between two-level systems and a common data bus provides a fast mechanism to produce multipartite entanglement. Our proposal combines resonant interactions and engineering of coupling strengths---between the qubits and the single mode---leading to well defined entangled states. Furthermore, we show that, if the two-level systems interact dispersively with the quantized mode, engineering of coupling strengths allows the controlled access of the symmetric Hilbert space of qubits.Comment: 5 pages, 4 figures. Submitted for publicatio

Sudden Birth Versus Sudden Death of Entanglement in Multipartite Systems

We study the entanglement dynamics of two cavities interacting with independent reservoirs. Expectedly, we observe that, as the cavity entanglement is depleted, it is transferred to the reservoir degrees of freedom. We find that when the cavity entanglement suddenly disappear, the reservoir entanglement suddenly and necessarily appears. Surprisingly, we show that this {\it entanglement sudden birth} can manifest before, simultaneously, or even after {\it entanglement sudden death}. Finally, we present an explanatory study of other entanglement partitions and of higher dimensional systems.Comment: 5 pages, 5 figures, accepted for publication in Physical Review Letter

Biochemical composition and physicochemical properties of Moringa oleifera seed oil

Moringa oleifera tree has been recognized internationally for its nutritional, therapeutic and medicinal properties. Dry seeds are rich sources of oil with a high potential of commercial exploitation. The present study reports the physicochemical characterization, polyphenol content, DPPH radical scavenging capacity and fatty acid profile of moringa seed oil, and the chemical composition of the seed cultivated in Sonora, Mexico. Moisture, ash, protein and lipid contents in the seed were found to be 4.7, 5.8, 26 and 39%, respectively. The oil showed a refractive index of 1.4642. The saponification number was 183 mg KOH/g oil, iodine value: 75 g I/100 g of oil, acid value: 0.49 (% oleic acid). The polyphenol content was 0.137 mg of gallic acid equivalent/g and DPPH radical scavenging capacity was 87.39%. The moringa seed oil was rich (68%) in the major fatty acid, oleic acid (C18:1n9). Moringa oil extracted by sonication showed a fatty acid profile and physicochemical properties comparable to the oil from seeds grown in different regions of the world. The optimization of the oil extraction process on a large scale shows high potential, as the oil could be marketed as edible vegetable oil, for frying purposes, or as a functional ingredient

Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials

Glass-ceramic material prepared with sugar cane bagasse ash as one of the raw materials was characterized to determine some important properties for its application as a coating material. X-ray diffraction patterns showed that wollastonite-2M (CaSiO3) was the major glass-ceramic phase. The Rietveld method was used to quantify the crystalline (60 wt.%) and vitreous (40 wt.%) phases in the glass-ceramic. The microstructure (determined by scanning electron microscopy) of this material had a marble appearance, showing a microporous network of elongated crystals with some areas with dendritic, feather-like ordering. Microhardness data gave a mean hardness value of 564.4 HV (Vickers-hardness), and light microscopy disclosed a greenish brown colored material with a vitreous luster.The authors acknowledge the financial support provided through the project TRISOLCOOLAB (ENE2010-20650-CO2-01-02), Ministerio de Ciencia e Innovación of the Spanish government for facilitating the presentation of this work in CRYSTALLIZATION 2012. Also, the authors thank FAPESP (2008/04368-4) for financial support of this project and FUNDUNESP (01090/2011-DFP) for financial aid.Peer reviewe

Twelfth Intercomparison Campaign of the Regional Brewer Calibration Center Europe: El Arenosillo Atmospheric Sounding Station, Huelva, Spain, 29 May to 9 June 2017

Editado por Alberto Redondas y Stoyka NetchevaThe twelfth European Brewer Intercomparison Campaign was organized by the Regional Brewer Calibration Center for Europe (RBCC-E) in collaboration with the “Area of Instrumentation and Atmospheric Research Area” of Instituto Nacional de Tecnica Aeroespacial (INTA), with the support of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) and the EUBREWNET ES1207 COST Action. Alongside the campaign, the ATMOZ (Traceability of Atmospheric Total Ozone) project workshop took place at the station. In addition, this event was also used as a demonstration exercise of the calibration methodologies and error assessment developed by the project (Gröbner et al., 2018)

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Presentación realizada en: Nordic Ozone Group Meeting (2021), celebrado el 21 de abril de 2021 de manera virtual