Exact Bethe Ansatz solution for An−1A_{n-1} chains with non-SUq(n)SU_{q}(n) invariant open boundary conditions

The Nested Bethe Ansatz is generalized to open and independent boundary conditions depending on two continuous and two discrete free parameters. This is used to find the exact eigenvectors and eigenvalues of the $A_{n-1}$ vertex models and $SU(n)$ spin chains with such boundary conditions. The solution is found for all diagonal families of solutions to the reflection equations in all possible combinations. The Bethe ansatz equations are used to find de first order finite size correction.Comment: Two references adde

El control de la inmigración irregular en España: compromisos y desarrollos

Esta contribución realiza un examen crítico de los desarrollos más recientes producidos en la práctica española en relación con el control de la inmigración irregular. Se analizan tanto los compromisos gestados en el marco del proceso de integración europea y sus implicaciones relacionadas con el control de las fronteras exteriores, como los desarrollos convencionales y «paraconvencionales» (acuerdos no normativos, memorandos de entendimiento, etc.) concluidos por España y orientados al control de los flujos de personas. En este orden, el examen incide igualmente en las obligaciones internacionales de España en materia de derechos humanos y aborda finalmente los desarrollos internos más recientes, tanto las modificaciones legislativas aprobadas o en curso como la práctica administrativa. Asimismo, se valora críticamente la congruencia de este conjunto de desarrollos y se analizan episodios como las «devoluciones en caliente», abordados a la luz de los parámetros precedentes

Exact solution of the SUq(n)SU_{q}(n) invariant quantum spin chains

The Nested Bethe Ansatz is generalized to open boundary conditions. This is used to find the exact eigenvectors and eigenvalues of the $A_{n-1}$ vertex model with fixed open boundary conditions and the corresponding $SU_{q}(n)$ invariant hamiltonian. The Bethe Ansatz equations obtained are solved in the thermodynamic limit giving the vertex model free energy and the hamiltonian ground state energy including the corresponding boundary contributions.Comment: 29 page

The estación de las Delicias site (Madrid) and paleolithic research in the Manzanares valley

El yacimiento madrileño de las Delicias, excavado por Obermaier y Wernert en 1918, ha sido durante décadas uno de los más notables del conjunto de localidades paleolíticas clásicas del valle del Manzanares. En el presente artículo se hace un repaso crítico de la documentación ofrecida por la antigua excavación, se evalúan historiográficamentelas distintasinterpretaciones vertidas sobre la industria del yacimiento y se enumeran algunos de los objetivos sobre los que construir un nuevo proyecto de excavación sobrelos depósitos aún conservados del mismo.The archaeological site of Las Delicias (Madrid) excavated by Obermaier andWernert in 1918, it has been one of the most important classic palaeolithic sites of the Manzanares valley for years. In this paper we offer a critical review of all the data caming from ancient excavation, together with an historiographical evaluation of the different interpretations based on lithic industry of the site, and finally we want to set some objectives looking for a new archaeological research in the Delicia´s remaining sediment

Integrable open-boundary conditions for the supersymmetric t-J model. The quantum group invariant case

We consider integrable open--boundary conditions for the supersymmetric t--J model commuting with the number operator $n$ and $S^{z}$. Four families, each one depending on two arbitrary parameters, are found. We find the relation between Sklyanin's method of constructing open boundary conditions and the one for the quantum group invariant case based on Markov traces. The eigenvalue problem is solved for the new cases by generalizing the Nested Algebraic Bethe ansatz of the quantum group invariant case (which is obtained as a special limit). For the quantum group invariant case the Bethe ansatz states are shown to be highest weights of $spl_{q}(2,1)$.Comment: Latex, 24 pages. Some new comments and references. Final version to appear in Nucl. Phys.

Globular Clusters: DNA of Early-Type galaxies?

This paper explores if the mean properties of Early-Type Galaxies (ETG) can be reconstructed from "genetic" information stored in their GCs (i.e., in their chemical abundances, spatial distributions and ages). This approach implies that the formation of each globular occurs in very massive stellar environments, as suggested by some models that aim at explaining the presence of multi-populations in these systems. The assumption that the relative number of globular clusters to diffuse stellar mass depends exponentially on chemical abundance, [Z/H], and the presence of two dominant GC sub-populations blue and red, allows the mapping of low metallicity halos and of higher metallicity (and more heterogeneous) bulges. In particular, the masses of the low-metallicity halos seem to scale up with dark matter mass through a constant. We also find a dependence of the globular cluster formation efficiency with the mean projected stellar mass density of the galaxies within their effective radii. The analysis is based on a selected sub-sample of galaxies observed within the ACS Virgo Cluster Survey of the {\it Hubble Space Telescope}. These systems were grouped, according to their absolute magnitudes, in order to define composite fiducial galaxies and look for a quantitative connection with their (also composite) globular clusters systems. The results strengthen the idea that globular clusters are good quantitative tracers of both baryonic and dark matter in ETGs.Comment: 20 pages, 28 figures and 5 table

El marco jurídico internacional y europeo de acogida de los refugiados y la incidencia de la declaración UE-Turquía.

Curso de Verano 2016 : 14 y 15 de julio de 2016 Palacio Miramar, Donostia-San Sebastián. XV Premio Investigación Francisco Javier de Landaburu Universitas 2016

Circular strings, wormholes and minimum size

The quantization of circular strings in an anti-de Sitter background spacetime is performed, obtaining a discrete spectrum for the string mass. A comparison with a four-dimensional homogeneous and isotropic spacetime coupled to a conformal scalar field shows that the string radius and the scale factor have the same classical solutions and that the quantum theories of these two models are formally equivalent. However, the physically relevant observables of these two systems have different spectra, although they are related to each other by a specific one-to-one transformation. We finally obtain a discrete spectrum for the spacetime size of both systems, which presents a nonvanishing lower bound.Comment: 11 pages, LaTeX2e, minor change