Properties of nuclear pastas

C. O. DORSO; G.FRANK; J. LOPEZ

Frontiers in Physics

Frontiers Media SA

Lugar: lausane; Año: 2021 p. 1 - 85

2296-424X

In this Review we study the nuclear pastas as they are expected to be formed in neutron starcores. We start with a study of the pastas formed in nuclear matter (composed of protons andneutrons), we follow with the role of the electron gas on the formation of pastas, and we theninvestigate the pastas in neutron star matter (nuclear matter embedded in an electron gas).Nuclear matter (NM) at intermediate temperatures (1 MeV . T . 15 MeV), at saturationand sub-saturation densities, and with proton content ranging from 30% to 50% was found tohave liquid, gaseous and liquid-gas mixed phases. The isospin-dependent phase diagram wasobtained along with the critical points, and the symmetry energy was calculated and compared toexperimental data and other theories. At low temperatures (T . 1 MeV) NM produces crystal-likestructures around saturation densities, and pasta-like structures at sub-saturation densities.Properties of the pasta structures were studied with cluster-recognition algorithms, caloric curve,the radial distribution function, the Lindemann coefficient, Kolmogorov statistics, Minkowskifunctionals; the symmetry energy of the pasta showed a connection with its morphology.Neutron star matter (NSM) is nuclear matter embedded in an electron gas. The electron gas isincluded in the calculation by the inclusion of an screened Coulomb potential. To connect the NMpastas with those in neutron star matter (NSM), the role the strength and screening length of theCoulomb interaction have on the formation of the pastas in NM was investigated. Past was foundto exist even without the presence of the electron gas, but the effect of the Coulomb interaction isto form more defined pasta structures, among other effects. Likewise, it was determined that thereis a minimal screening length for the developed structures to be independent of the cell size.Neutron star matter was found to have similar phases as NM, phase transitions, symmetryenergy, structure function and thermal conductivity. Like in NM, pasta forms at around T ≈ 1.5MeV, and liquid-to-solid phase changes were detected at T ≈ 0.5 MeV. The structure function andthe symmetry energy were also found to depend on the pasta structures.