Photoluminiscence of a quantum dot hybridized with a continuum

We calculate the intensity of photon emission from a trion in a single quantum dot, as a function of energy and gate voltage, using the impurity Anderson model and variational wave functions. Assuming a flat density of conduction states and constant hybridization energy, the results agree with the main features observed in recent experiments: non-monotonic dependence of the energy on gate voltage, non-Lorentzian line shapes, and a line width that increases near the regions of instability of the single electron final state to occupations zero or two.Comment: 4 pages, 3 figures, Journal-ref adde

Geometry-induced enhancement factor improvement in covered-gold-nanorod-dimer antennas

Illuminated gapped-gold-nanorod dimers hold surface plasmon polaritons (SPPs) that can be engineered, by an appropriate choice of geometrical parameters, to enhance the electromagnetic field at the gap, allowing applications in molecular detection via surface-enhanced Raman spectroscopy (SERS). Envisioning hybrid devices in which the SERS spectroscopy of molecules in the gap is complemented by electrical measurements, it arises the question of designing efficient geometries to contact the nanorods without decreasing the enhancement factor (EF) of the nanoantenna, i.e., the figure of merit for SERS spectroscopy. Within this framework we theoretically study the feasibility to fabricate designs based on covering with gold the far-from-the-gap areas of the dimer. We show that by tuning the geometrical parameters of the designs these systems can reach enhancement factors larger than the best achieved in the uncovered dimer: this supremacy survives even in the presence of dimer asymmetries and vacancies at the interfaces between the nanorods and the covering layers. Our results show that geometrical modifications away from the gap can improve the optical response at the gap, thus enabling the use of these devices both for hybrid and optical applications.Comment: 10 pages, 8 figure

Effect of the excitation setup in the improved enhancement factor of covered-gold-nanorod-dimer antennas

Devices possessing the ability to sense both electrically and optically molecular targets are of fundamental and technological interest. Towards this end, it has been shown that covering the ends of gapped gold-nanorod-dimer nanoantennas can improve the enhancement factor (EF) that quantifies the nanoantenna efficiency for surface-enhancement Raman spectroscopy (SERS) for an incident wave coming from the top of the sample. Here, as the covering breaks the top-bottom symmetry, we investigate the behaviour of the EF for excitation coming from the bottom of the sample. This is relevant in presence of a reflecting substrate or due to the placement of the device in a cavity field. We also study the case of a superposition of waves coming from both directions in the limit cases in which a node or an antinode of the total incident field lies at the center of the gold nanorods. In all these situations we find that the EF of the covered device can continue to be higher than for the uncovered case when the geometrical parameters are tuned to the peak values of the calculated enhancement factor

Subjectively complex part, indivisibility and annullability for relative incapacity: The darkest article of the Peruvian Civil Code also celebrates its thirtieth anniversary (and says good-bye?)

The Peruvian Civil Code commemorates its thirty years of existence. Some of its rules’content is clear, while some other rules are –in the words of the author– dark andquestionable.  One of these controversial rules in its meaning and application is that contained in article 226 of the Code, relatedwith a person’s legal capacity.In this article, the author makes a historical and comparative analysis of such article, to then approach the problems contained in it, contrasting their role in the current social reality and verifying if such figure is still useful in our legal system.El Código Civil peruano cumple treinta años de vigencia. Algunas de sus disposiciones son claras respecto a su contenido y otras son –en palabras del autor– oscuras y discutibles. Una de las normas controvertidas en su significado y aplicación es la contenida en el artículo 226del Código, relacionado con la capacidad jurídica de la persona.En este artículo, el autor realiza un análisis histórico-comparativo del mencionado artículo, para luego abordar los problemas en él contenidos, contrastar su función en la realidad social actual y verificar si tal figura es aun útil en nuestro ordenamiento jurídico

METIS: multiple extraction techniques for informative sentences

Summary: METIS is a web-based integrated annotation tool. From single query sequences, the PRECIS component allows users to generate structured protein family reports from sets of related Swiss-Prot entries. These reports may then be augmented with pertinent sentences extracted from online biomedical literature via support vector machine and rule-based sentence classification systems. Availability: Contact: [email protected] Supplementary informatio

Microcavity exciton-polariton mediated Raman scattering: Experiments and theory

We studied the intensity of resonant Raman scattering due to optical phonons in a planar II-VI-type semiconductor microcavity in the regime of strong coupling between light and matter. Two different sets of independent experiments were performed at near outgoing resonance with the middle polariton (MP)branch of the cavity. In the first, the Stokes-shifted photons were kept at exact resonance with the MP, varying the photonic or excitonic character of the polariton. In the second, only the incoming light wavelength was varied, and the resonant profile of the inelastic scattered intensity was studied when the system was tuned out of the resonant condition. Taking some matrix elements as free parameters, both independent experiments are quantitatively described by a model which incorporates lifetime effects in both excitons and photons, and the coupling of the cavity photons to the electron-hole continuum. The model is solved using a Green's function approach which treats the exciton-photon coupling nonperturbatively.Comment: 10 pages, 6 figure