Shape transitions in the weak entanglement approximation.

Atomic nuclei can exhibit rapid changes in deformation along isotopic chains. Many-body methods such as the full-configuration interaction method struggle to investigate these shape transitions due to the exponentially increasing dimensionality of the model. A recently developed importance truncation scheme dubbed the weak entanglement approximation allows us to investigate these shape transitions at a small fraction of the configuration interaction problem size. In this framework, deformation sensitive observables are calculated for Chromium and Krypton even isotope chains, successfully reproducing the deformed to spherical pattern expected around the semi-magic N = 28 subshell closure. The results are compared to full configuration interaction calculations to compare this new method's applicability to low-lying nuclear structure.