The Equation of State of Neutron Stars and the Role of Nuclear Experiments

1S0 Pairing Gaps, Chemical Potentials and Entrainment Matrix in Superfluid Neutron-Star Cores for the Brussels–Montreal Functionals

“…and ε Λ is a cutoff above the Fermi level to regularize the ultraviolet divergences (see Section 3.1). Expressing the hyperbolic functions in terms of the exponential function, we can alternatively rewrite (43) and (44) as…”

“…The functional BSk24 has been recently employed for determining the composition and the equation of state of dense matter throughout all regions of a neutron star [19,20] including the pasta mantle [21] and allowing for strong magnetic fields [22]. More importantly, as shown in [23,43,44], this functional turns out to be in very good agreement with existing astrophysical observations including those from the binary neutron-star merger GW170817 [45] as well as from PSR J0740+6620 and PSR J0030+0451 by the Neutron star Interior Composition Explorer (NICER) [46][47][48][49]. Results for the entrainment matrix at finite temperatures but in the absence of superflows have been recently published in [11] within Landau's theory using values for the Landau parameters calculated for the Brussels-Montreal functionals including BSk24 and setting arbitrarily the critical temperatures.…”

Nuclear physics inputs for dense-matter modelling in neutron stars. The nuclear equation of state

“…Finally, we remind that the hypothesis underlying the employed meta-modelling is that only nucleons and leptons are present in the NS core, which might be restrictive at high densities in NSs. However, this model can be also used as a null hypothesis to infer from the astrophysical data the presence of additional non-nucleonic degrees of freedom (see the discussion in [43]).…”