A survey of nuclear pasta in the intermediate-density regime I: Shapes and energies

Journal Article · 23 August 2019 · Physical Review C

DOI: https://doi.org/10.1103/PhysRevC.100.045806 · OSTI ID:1571271

Schuetrumpf, Bastian ^[1]; Martínez-Pinedo, Gabriel ^[2]; Afibuzzaman, Md ^[3]; Aktulga, Hasan Metin ^[3]

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1. GSI Helmholzzentrum fur Schwerionenforschung, Darmstadt (Germany)
2. GSI Helmholzzentrum fur Schwerionenforschung, Darmstadt (Germany); Technische Univ. Darmstadt, Darmstadt (Germany)
3. Michigan State Univ., East Lansing, MI (United States)

Nuclear pasta, emerging due to the competition between the long-range Coulomb force and the short-range strong force, is believed to be present in astrophysical scenarios, such as neutron stars and core-collapse supernovae. Its structure can have a high impact e.g. on neutrino transport or the tidal deformability of neutron stars. We study several possible pasta configurations, all of them minimal surface configurations, which are expected to appear in the mid-density regime of nuclear pasta, i.e. around 40% of the nuclear saturation density. In particular we are interested in the energy spectrum for different pasta configurations considered. Employing the density functional theory (DFT) approach, we calculate the binding energy of the different configurations for three values of the proton content X_P = 1/10, 1/3 and 1/2, by optimizing their periodic length. We study finite temperature effects and the impact of electron screening. [Results] Nuclear pasta lowers the energy significantly compared to uniform matter, especially for X_P ≥ 1/3. However, the different configurations have very similar binding energies. For large proton content, X_P ≳ 1/3, the pasta configurations are very stable, for lower proton content temperatures of a few MeV are enough for the transition to uniform matter. Electron screening has a small influence on the binding energy of nuclear pasta, but increases its periodic length. Nuclear pasta in the mid-density regime lowers the energy of the matter for all proton fractions under study. Here, it can survive even large temperatures of several MeV. Since various configurations have very similar energy, it is to expect that many configurations can coexist simultaneously already at small temperatures.

• Research Organization: Michigan State Univ., East Lansing, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR). Scientific Discovery through Advanced Computing (SciDAC)
• Contributing Organization: GSI Helmholzzentrum fur Schwerionenforschung, Darmstadt (Germany) Institut fur Kernphysik (Theoriezentrum), Technische Universitat Darmstadt (Germany)
• Grant/Contract Number: SC0018083
• OSTI ID: 1571271
• Journal Information: Physical Review C, Vol. 100, Issue 4; ISSN 2469-9985
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English