Proto-neutron star inner crust

We show that the inclusion of non-linear mixing terms arising from the ion centre-of-mass motion leads to a breakdown of the ensemble equivalence between the one-component and multi-component approach. Our findings also illustrate that the abundance of light nuclei becomes important and eventually dominates the whole distribution at higher density and temperature in the crust. This is reflected in the impurity parameter, which, in turn, may have a potential impact on neutron-star cooling.

For practical application to astrophysical simulations, we also provide a fitting formula for the impurity parameter in the proto-neutron-star inner crust. Our results obtained within a self-consistent multi-component approach show important differences in the prediction of the proto-neutron-star composition with respect to those obtained with a one-component approximation or a perturbative multicomponent approximation, particularly in the deeper region of the crust.

This highlights the importance of a full, self-consistent multi-component plasma calculation for reliable predictions of the proto- neutron-star crust composition.