Laboratory link : http://irfu.cea.fr/dphn/index.php
The theoretical description from first principles, i.e. in a so-called ab initio fashion, of atomic nuclei containing more than ~12 nucleons has become possible only recently thanks to crucial developments in many-body theory and the availability of increasingly powerful high-performance computers. Such ab initio techniques are being successfully applied to study the structure of nuclei starting from the lighter isotopes and reaching today mid-mass nuclei containing up to about 80 nucleons. The extension to even heavier systems requires decisive breakthroughs regarding the storage and running time induced by any of the available many-body methods. In this context, the goal of the thesis is to formulate and apply the recently proposed Importance Truncation (IT) techniques within the frame of Gorkov Self-consistent Green’s function calculations, a specific ab initio technique devised at CEA Saclay over the last 9 years, as a way to select a priori and systematically many-body basis states that do contribute significantly to many-body correlations. The project will exploit the latest advances in nuclear theory, including the use of nuclear interactions from chiral effective field theory and renormalisation group techniques, as well as high-performance computing codes and resources. The work will consist in formal developments, computational tasks and application of the new technology to cases of experimental interest. International collaborations constitute an integral part of the project.