The theoretical description of neutron stars, relevant to the interpretation of
a variety of astrophysical observations,
requires a quantitative understanding of both equilibrium and non equilibrium
properties of nuclear matter at high density.
However, while equilibrium properties---e.g. the zero-temperature equation of state (EOS)---are generally obtained
from realistic dynamical models, strongly constrained from nuclear systematics and
nucleon-nucleon scattering data, theoretical studies of the dynamical properties, such as the response functions, often
resort to oversimplified
models of nuclear interactions.
The work aimed at developing a consistent description of the nuclear matter EOS and electroweak response in
the low-energy region, carried out by my group over the past decade, has been largely based on a density-dependent
effective interaction, derived from a highly realistic nuclear hamiltonian using the formalism of correlated basis
functions (CBF) and the cluster expansion technique [Phys. Rev. Lett. 99 (2007) 232501;
Phys. Rev. C 83 (2011) 054003].
By construction, the CBF effective interaction provides the same EOS obtained from state-of-the-art ab initio
approaches, such as Fermi Hyper-Netted Chain (FHNC) and Green's Function Monte Carlo (GFMC). However, unlike the bare
nucleon-nucleon potential, it is suitable to carry out perturbative
calculations of a variety of nuclear matter properties, including the dynamic responses, using the basis
states of the non interacting system.
The calculated responses to neutral current weak interactions with neutrinos carrying energies of few MeV have
been used to obtain the corresponding contributions to the neutrino mean free path in both pure neutron matter
and isospin-symmetric matter at zero temperature [Phys. Rev. C 89 (2014) 025804].
In addition, combining the effective interaction formalism to Landau's theory of normal Fermi liquids
we have been able to extend its applicability to the regime of non vanishing temperature, relevant to supernovae and newly formed neutron stars [Phys. Rev. C 87 (2013) 014601].
In the past few years, the CBF efective interactions has been employed to carry out systematic calculations
of the equation of state of nuclear matter with arbitrary neutron excess and nonzero temperature
[Phys. Rev. C 96 (2017) 054301]. The fisrt results of this work have been employed
to study the neutrino luminosity and gravitational wave emission of protoneutron stars during
the Kelvin-Helmoltz evolutionary phase [Phys. Rev. D 96 (2017) 043015].