A quantitative witness for Greenberger-Horne-Zeilinger entanglement

Along with the vast progress in experimental quantum technologies there is an increasing demand for the quantification of entanglement between three or more quantum systems. Theory still does not provide adequate tools for this purpose. The objective is, besides the quest for exact results, to develop operational methods that allow for efficient entanglement quantification. Here we put forward an analytical approach that serves both these goals. We provide a simple procedure to quantify Greenberger-Horne-Zeilinger-type multipartite entanglement in arbitrary three-qubit states. For two qubits this method is equivalent to Wootters' seminal result for the concurrence. It establishes a close link between entanglement quantification and entanglement detection by witnesses, and can be generalised both to higher dimensions and to more than three parties.

Relaciones comerciales entre puertos franceses y guipuzcoanos en las décadas finales del siglo XVI y la primera mitad del siglo XVII: síntoma de vitalidad económica

[ES]El presente trabajo presenta una fuente documental infrautilizada, la de los libros de manifestaciones, que representa un interesantísimo instrumento de estudio para el conocimiento de la realidad comercial e industrial de la Guipúzcoa de los siglos XVI y XVII. Esta documentación permite matizar algunas de las afirmaciones que durante décadas han venido marcando la historiografía vasca sobre la tan manida “crisis del siglo XVII”, más en consonancia con los criterios que en los últimos años se vienen imponiendo en los ámbitos español y europeo. Las relaciones comerciales con puertos, principalmente franceses, que se pueden seguir a través de las mencionadas fuentes permiten seguir los fluidos intercambios y las llegadas de cereales y bastimentos, así como la salida de hierro y moneda desde algunos de los principales puertos guipuzcoanos. Una de las principales conclusiones es que la exportación de hierro a los puertos franceses tuvo continuidad a fines del siglo XVI y principios del siglo XVII

Documentación espacial del patrimonio: preservación de la información. Necesidades, posibilidades, estrategias y estándares

[ES] La parte práctica de esta tesis se centra en un proyecto ERASMUS realizado en el Monasterio de San Prudencio de Monte Laturce (Clavijo, La Rioja). Dicho proyecto aparece descrito en varios registros de este mismo repositorio a los que se puede acceder a través del siguiente:

Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago

The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We review the terrestrial Late Cretaceous record from Europe and discuss its importance for understanding the paleogeography, ecology, evolution, and extinction of land-dwelling vertebrates. We review the major Late Cretaceous faunas from Austria, Hungary, France, Spain, Portugal, and Romania, as well as more fragmentary records from elsewhere in Europe. We discuss the paleogeographic background and history of assembly of these faunas, and argue that they are comprised of an endemic 'core' supplemented with various immigration waves. These faunas lived on an island archipelago, and we describe how this insular setting led to ecological peculiarities such as low diversity, a preponderance of primitive taxa, and marked changes in morphology (particularly body size dwarfing). We conclude by discussing the importance of the European record in understanding the end-Cretaceous extinction and show that there is no clear evidence that dinosaurs or other groups were undergoing long-term declines in Europe prior to the bolide impact.