Impact of complex many-body correlations on electron capture in thermally excited nuclei around 78Ni

We link complex many-body correlations, which play a decisive role in the structural properties of atomic nuclei, to the electron capture occurring during star evolution. The recently developed finite-temperature response theory, taking into account the coupling between single-nucleon and collective degrees of freedom, is applied to spin-isospin transitions, which dominate the electron capture rates. Calculations are performed for Ni-78 and for the surrounding even-even nuclei associated with a high-sensitivity region of the nuclear chart in the context of core-collapse supernova simulations. The obtained electron capture rates are compared to those of a simpler thermal quasiparticle random phase approximation (TQRPA), which is standardly used in such computations. The comparison indicates that correlations beyond TQRPA lead to significantly higher electron capture rates under the typical thermodynamical conditions.

Automated summary

This study links complex many-body correlations to electron capture during star evolution, utilizing finite-temperature response theory to calculate electron capture rates for spin-isospin transitions. The results show that correlations beyond the thermal quasiparticle random phase approximation significantly increase electron capture rates under typical thermodynamical conditions.