Nuclear Structure in the Framework of the Unitary Correlation Operator Method

Correlations play a crucial role in the nuclear many-body problem. We give an overview of recent developments in nuclear structure theory aiming at the description of these interaction-induced correlations by unitary transformations. We focus on the Unitary Correlation Operator Method (UCOM), which offers a very intuitive, universal and robust approach for the treatment of short-range correlations. We discuss the UCOM formalism in detail and highlight the connections to other methods for the description of short-range correlations and the construction of effective interactions. In particular, we juxtapose UCOM with the Similarity Renormalization Group (SRG) approach, which implements the unitary transformation of the Hamiltonian through a very flexible flow-equation formulation. The UCOM- and SRG-transformed interactions are compared on the level of matrix elements and in many-body calculations within the no-core shell model and with Hartree-Fock plus perturbation theory for a variety of nuclei and observables. These calculations provide a detailed picture of the similarities and differences as well as the advantages and limitations of unitary transformation methods.Comment: 72 pages, 31 figure

Nuclear Structure - "ab initio"

An ab-initio description of atomic nuclei that solves the nuclear many-body problem for realistic nuclear forces is expected to possess a high degree of predictive power. In this contribution we treat the main obstacle, namely the short-ranged repulsive and tensor correlations induced by the realistic nucleon-nucleon interaction, by means of a unitary correlation operator. This correlator applied to uncorrelated many-body states imprints short-ranged correlations that cannot be described by product states. When applied to an observable it induces the correlations into the operator, creating for example a correlated Hamiltonian suited for Slater determinants. Adding to the correlated realistic interaction a correction for three-body effects, consisting of a momentum-dependent central and spin-orbit two-body potential we obtain an effective interaction that is successfully used for all nuclei up to mass 60. Various results are shown.Comment: 9 pages, Invited talk and poster at the international symposium "A New Era of Nuclear Structure Physics" (NENS03), Niigata, Japan, Nov. 19-22, 200

Influence of polarizability on metal oxide properties studied by molecular dynamics simulations

We have studied the dependence of metal oxide properties in molecular dynamics (MD) simulations on the polarizability of oxygen ions. We present studies of both liquid and crystalline structures of silica (SiO2), magnesia (MgO) and alumina (Al2O3). For each of the three oxides, two separately optimized sets of force fields were used: (i) Long-range Coulomb interactions between oxide and metal ions combined with a short-range pair potential. (ii) Extension of force field (i) by adding polarizability to the oxygen ions. We show that while an effective potential of type (i) without polarizable oxygen ions can describe radial distributions and lattice constants reasonably well, potentials of type (ii) are required to obtain correct values for bond angles and the equation of state. The importance of polarizability for metal oxide properties decreases with increasing temperature.Comment: 8 pages, 7 figure

Immigració i escola: experiències d’integració a Hamburg

L’article tracta, en primer lloc, el sistema escolar a l’Estat Federal d’Hamburg (República Federal d’Alemanya) i les mesures adoptades per a la integració de l’alumnat immigrant. Tot seguit, s’explica fil per randa l’experiència de l’escola Wielandstraße i la seva organització de classes de transició al sistema escolar regular. Es detallen els procediments per aconseguir el màxim èxit en els processos d’integració i es fa una valoració crítica de l’experiència. Finalment es fa una anàlisi i es presenten propostes de la didàctica de la d’educació física des d’una perspectiva intercultural

Inmigración y escuela: experiencias de integración en Hamburgo

El artículo trata, en primer lugar, el sistema escolar en el Estado Federal de Hamburgo (República Federal de Alemania) y las medidas adoptadas para la integración del alumnado inmigrante. A continuación, se explica en detalle la experiencia de la escuela Wielandstraße y su organización de clases de transición al sistema escolar regular. Se detallan los procedimientos para lograr el máximo éxito en los procesos de integración y se hace una valoración crítica de la experiencia. Por último, se analiza y se presentan propuestas de la didáctica de la de Educación Física desde una perspectiva intercultural

The Swedish Sámi Parliament: A challenged recognition?

Work Package 4: National Case Studies of Challenges to Tolerance in Political LifeThe ACCEPT PLURALISM project (2010-2013) is funded by the European Commission under the Seventh Framework Programme, Socio-economic Sciences and Humanities. (Call FP7-SSH-2009-A, Grant Agreement no: 243837). Coordinator: Prof. Anna Triandafyllidou, Robert Schuman Centre for Advanced Studies, European University Institute