Description:Porting and development of numerical codes on the GRID for the study of quantum many-body systems
Abstract:It is a well known fact that the quantum many-body problem can not be solved exactly and one has to resort to approximate methods to study their properties.
<br> Moreover, modern studies of ground state and excited states of many body systems require more and more powerful computer resources. <br>The GRID infrastructure is thus a particularly well suited tool for their implementation.
<br>Two different lines of investigation have been mainly carried out till now.
<br>The first one is directed to the development of an extension of the Random Phase Approximation (RPA) aimed to give a better description of ground state correlations. <br>RPA is a microscopic approach largely used in the study of collective excitations in many-body systems and is usually carried out in order to improve the standard mean field description of a physical system, by introducing some correlations which are neglected at mean field level.<br> However, RPA presents some limits and many efforts are still done by the scientific community in order to overcome them by improving the RPA description of ground state correlations. In such a line of investigation, we have developed an improved RPA approach in order to take in account correlations in a self-consistent way and we have applied it in the analysis of electronic properties of several Metal Clusters. In particular we have analysed the dipole plasmon modes and we have found a good agreement with experimental results, better than standard RPA does.
In the second line of investigation we have studied the implementation of Parallel Eigensolvers on the Grid infrastructure. <br>The eigenvalue problem is one of the most recurring numerical task in scientific and engineering disciplines. <br>For example, Shell Model or RPA calculations, that are fundamental tools for the study of many-body systems, consist, from a numerically point of view, in solving an eigenvalue problem. The matrix to be diagonalized, is typically the representation of the Hamiltonian operator in a finite basis. A co