Experimental investigations of the dipolar interactions between single Rydberg atoms

This review summarizes experimental works performed over the last decade by several groups on the manipulation of a few individual interacting Rydberg atoms. These studies establish arrays of single Rydberg atoms as a promising platform for quantum state engineering, with potential applications to quantum metrology, quantum simulation and quantum information

Recursos multimedia y protagonismo del rey Juan Carlos I Un análisis de ABC.es y ELPAÍS.com (2009 – 2011)*

A través de la multimedialidad los cibermedios pueden articular un lenguajemás flexible que el de los medios convencionales. En nuestro análisis decontenido, focalizado en las alusiones a Juan Carlos I durante 2009 y 2011,evaluamos tanto la integración de recursos multimedia en ABC.es y ELPAÍS.com, como el protagonismo concedido al rey de España en esos recursos.En los resultados destaca la elevada implementación audiovisual de lamonarquía: casi seis unidades de cada diez, en ABC.es, y casi ocho de cadadiez, en ELPAÍS.com, poseían algún tipo de recurso audiovisual. La conclusiónmás importante es la relativa al protagonismo: ambas cabeceras, a prioridistanciadas simbólicamente, denotan un patrón estructural semejante en lacaracterización del monarca, lo que evidencia la elevada direccionalidad delas informaciones descriptivas de la institución monárquica

Measurement of the Angular Dependence of the Dipole-Dipole Interaction Between Two Individual Rydberg Atoms at a F\"orster Resonance

We measure the angular dependence of the resonant dipole-dipole interaction between two individual Rydberg atoms with controlled relative positions. By applying a combination of static electric and magnetic fields on the atoms, we demonstrate the possibility to isolate a single interaction channel at a F\"orster resonance, that shows a well-defined angular dependence. We first identify spectroscopically the F\"orster resonance of choice and we then perform a direct measurement of the interaction strength between the two atoms as a function of the angle between the internuclear axis and the quantization axis. Our results show good agreement with the expected angular dependence $\propto(1-3\cos^2\theta)$, and represent an important step towards quantum state engineering in two-dimensional arrays of individual Rydberg atoms.Comment: 5 pages, 4 figure

Synthetic three-dimensional atomic structures assembled atom by atom

We demonstrate the realization of large, fully loaded, arbitrarily-shaped three-dimensional arrays of single atoms. Using holographic methods and real-time, atom-by-atom, plane-by-plane assembly, we engineer atomic structures with up to 72 atoms separated by distances of a few micrometres. Our method allows for high average filling fractions and the unique possibility to obtain defect-free arrays with high repetition rates. These results find immediate application for the quantum simulation of spin Hamiltonians using Rydberg atoms in state-of-the-art platforms, and are very promising for quantum-information processing with neutral atoms.Comment: 5 pages, 3 figure

An atom-by-atom assembler of defect-free arbitrary 2d atomic arrays

Large arrays of individually controlled atoms trapped in optical tweezers are a very promising platform for quantum engineering applications. However, to date, only disordered arrays have been demonstrated, due to the non-deterministic loading of the traps. Here, we demonstrate the preparation of fully loaded, two-dimensional arrays of up to 50 microtraps each containing a single atom, and arranged in arbitrary geometries. Starting from initially larger, half-filled matrices of randomly loaded traps, we obtain user-defined target arrays at unit filling. This is achieved with a real-time control system and a moving optical tweezers that performs a sequence of rapid atom moves depending on the initial distribution of the atoms in the arrays. These results open exciting prospects for quantum engineering with neutral atoms in tunable geometries

Coherent dipole-dipole coupling between two single atoms at a F\"orster resonance

Resonant energy transfers, i.e. the non-radiative redistribution of an electronic excitation between two particles coupled by the dipole-dipole interaction, lie at the heart of a variety of chemical and biological phenomena, most notably photosynthesis. In 1948, F\"orster established the theoretical basis of fluorescence resonant energy transfer (FRET), paving the ground towards the widespread use of FRET as a "spectroscopic ruler" for the determination of nanometer-scale distances in biomolecules. The underlying mechanism is a coherent dipole-dipole coupling between particles, as already recognized in the early days of quantum mechanics, but this coherence was not directly observed so far. Here, we study, both spectroscopically and in the time domain, the coherent, dipolar-induced exchange of electronic excitations between two single Rydberg atoms separated by a controlled distance as large as 15 microns, and brought into resonance by applying a small electric field. The coherent oscillation of the system between two degenerate pair states occurs at a frequency that scales as the inverse third power of the distance, the hallmark of dipole-dipole interactions. Our results not only demonstrate, at the most fundamental level of two atoms, the basic mechanism underlying FRET, but also open exciting prospects for active tuning of strong, coherent interactions in quantum many-body systems.Comment: 4 pages, 3 figure

Tratamiento de género en las informaciones ofrecidas sobre el Día Internacional de la Mujer Trabajadora (2001-2010) en www.abc.es

En la siguiente comunicación se analiza la cobertura informativa del Día Internacional de la Mujer Trabajadora realizada por el periódico www.abc.es entre el 1 de enero de 2001 y el 31 de diciembre de 2010. Para ello se han combinado las técnicas de análisis de contenido informatizado a través de un examen de las palabras más frecuentes mediante una escala de categorías no jerarquizadas. Los resultados de este estudio señalan, por un lado, el mantenimiento de los estereotipos de este periódico según los cuales son las periodistas -y no los periodistas-, quienes construyen su propio discurso mientras que los contenidos de opinión -que cimentan el prestigio del diario-, tienden a favorecer la autoría masculina. Asimismo se describe www.abc.es como un modelo de fósil tecnológico que restringe la participación de los lectores, que evita la inclusión de enlaces, que resulta poco atractivo visualmente y que manifiesta una dejadez ortográfica presente en el polimorfismo de las alusiones encontradas a esta importante celebración. Por todo ello se propone la revisión de la cobertura informativa de este diario con el fin de homogeneizar su manual de estilo pero también de profundizar en los contenidos de una fecha clave reconocida por la ONU

Intermediate Journalistic Cultures. International Comparative Studies in Journalism

Defining journalistic culture is a complex process as it is necessary to explain on a general level the nature of culture is as a lifestyle. The attitudes of journalists are broadly embedded within meaning spheres that shape typical and traditional values of a common professional conduct. Throughout the last century, Western journalistic culture is taken as reference at all times to act as a model for imitation. However, this article presents the contextualization of different journalistic cultures as informative practice that currently varies from place to place and is determined by the different social, political, cultural and economic situation. The multiplicity-or multipolarity- in journalism, has led to the study of so-called intermediate journalistic cultures defined by having different features of the Western journalistic culture. Today, more than ever, those fragmented cultures mould and develop the static and mono-based standardization of all international journalistic features. The following study clarifies the singularities of journalistic cultures in different regions around the globe. It is a huge task, but necessary to underpin the theoretical notions of an important line of research born in recent decades: international comparative studies in journalism

Towards the democratization of journalism participant: three models of transparency in the management of coral interviews of MARCA.com

Las entrevistas corales de MARCA.com son una de las principales formas del ciberperiodismo híbrido: los usuarios organizan una entrevista ante los invitados que propone el cibermedio. Su atractivo radica, fundamentalmente, en los bajos costes de producción informativa, en la posibilidad de introducir el concepto de polifonía de Bakhtine (cit. por Araújo y Melo, 2003), y en la generación de un discurso más flexible, según describíamos en un trabajo anterior (Barredo y Oller, 2013a). La interrelación de estas características ocasiona que, en los cinco enfrentamientos entre el Real Madrid y el Barcelona de la temporada 2010 – 11, el 30% de las palabras totales se produjeran de manera coral (Barredo y Oller, 2013b). Sin embargo en esos estudios previos hemos percibido un funcionamiento arbitrario: el ciberdiario, además de las pautas explícitas de las normas de participación, escoge o descarta las preguntas en función de criterios no revelados. Con este artículo ofrecemos tres modelos de gestión que profundizan en el concepto de transparencia ciberperiodística, los cuales pueden evitar, en nuestra opinión, la fosilización de las entrevistas corales o su vinculación con formas derivadas del marketing (publientrevista) y no con el periodismo.Interviews of MARCA.com are one of the main forms of online hybrid journalism: users organize an interview with the guests proposed by the online media. Its appeal lies mainly in the low information production costs, the possibility of introducing the concept of Bakhtin’s polyphony (quoted by Araújo and Melo, 2003), and the generation of a more flexible speech, as we described in a previous paper (Barredo and Oller, 2013a). The interplay of these characteristics is the cause that in the five matches between Real Madrid and Barcelona in the season 2010-11, 30% of the total words came from coral interviews (Barredo and Oller, 2013b). However, in these previous studies we have noted an arbitrary function of the organization: in addition to the explicit guidelines in the rules of participation, the online newspaper discards or chooses questions based on undisclosed criteria. With this article we offer three management models which explore the concept of online transparency. Those models can avoid, in our opinion, the stagnation of the coral interviews or similar forms linked to direct marketing (advertorials) and not to journalism