In this Review we study the nuclear pastas as they are expected to be formed in neutron star cores. We start with a study of the pastas formed in nuclear matter (composed of protons and neutrons), we follow with the role of the electron gas on the formation of pastas, and we then investigate the pastas in neutron star matter (nuclear matter embedded in an electron gas).
Nuclear matter (NM) at intermediate temperatures (1 MeVT 15 MeV), at saturation and sub-saturation densities, and with proton content ranging from 30% to 50% was found to have liquid, gaseous and liquid-gas mixed phases. The isospin-dependent phase diagram was obtained along with the critical points, and the symmetry energy was calculated and compared to experimental data and other theories. At low temperatures (T 1 MeV) NM produces crystal-like structures 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, Minkowski functionals; 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 is included in the calculation by the inclusion of an screened Coulomb potential. To connect the NM pastas with those in neutron star matter (NSM), the role the strength and screening length of the Coulomb interaction have on the formation of the pastas in NM was investigated. Past was found to exist even without the presence of the electron gas, but the effect of the Coulomb interaction is to form more defined pasta structures, among other effects. Likewise, it was determined that there is 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, symmetry energy, structure function and thermal conductivity. Like in NM, pasta forms at around T ≈ 1.5 MeV, and liquid-to-solid phase changes were detected at T ≈ 0.5 MeV. The structure function and the symmetry energy were also found to depend on the pasta structures.
Contents
I. IntroductionA. The pasta B. The pasta in nuclear matter and in neutron star matter II. Nuclear matter A. Nuclear matter at intermediate temperatures B. Nuclear matter at low temperatures C. Summary of nuclear matter properties III. Electron gas: connecting nuclear matter with neutron star matter A. The strength of V C B. The screening length C. Summarizing the electron gas IV. Neutron star matter A. Symmetric neutron star matter B. Non-symmetric neutron star matter C. The symmetry energy D. Neutrino transport properties E. Properties of non-traditional pasta F. The nucleon thermal conductivity G. Summary of NSM properties V. Conclusion A. Nuclear matter B. The electron gas C. The pasta in neutron star matter VI. Appendices A. Classical Molecular Dynamics B. The Maxwell construction C. Nuclear symmetry energy from CMD at...