The No Core Gamow Shell Model for ab-initio Nuclear Structure Calculations

International audienceOne of the methods for calculating nuclear properties from first principles is the No-Core Shell Model (NCSM) [1]. Even though this method was applied with much success in the description of wellbound states, some problems arose when it was used for calculating properties of nuclei with a large radial extent ("halo" nuclei) or in the description of unbound states. The basic source of the problem was that a very large number of HO states are required to capture the physics of weakly bound "halo" nuclei, due to the Gaussian asymptotic behavior of the HO wavefunction. This does not mean that using HO states is wrong, but that they do not provide the correct scheme to calculate weakly-bound and unbound systems. This usually leads to non-converged results and the extrapolations to "infinite" basis were not very successful, until recently [2, 3]. Additionally, it was soon realized that the coupling to the continuum can also have an appreciable e ect on the properties of states close to threshold. This leads to a modification of many-body methods in order to include the continuum coupling in their frameworks [4-8]. In this work, our method of choice is the No-Core Gamow Shell Model, where the continuum is taken into account via the diagonalization of the many-body Hamiltonian in the Berggren basis [9]