Nuclear Pasta at Finite Temperature with the Time-Dependent Hartree-Fock Approach

6th Nuclear Physics in Astrophysics

物理学;天文学

Schuetrumpf, B.^1 ; Klatt, M.A.^2 ; Iida, K.^3 ; Maruhn, J.A.^1 ; Mecke, K.^2 ; Reinhard, P.-G.^2

Institut für Theoretische Physik, Universität Frankfurt, Frankfurt

D-60438, Germany^1

Institut für Theoretische Physik, Universität Erlangen-Nürnberg, Erlangen

D-91058, Germany^2

Department of Natural Science, Kochi University, 2-5-1 Akebono-cho, Kochi

780-8520, Japan^3

关键词: Euler characteristic;    Finite temperatures;    Maxwell-Boltzmann distribution;    Minkowski functionals;    Randomly distributed;    Three-dimensional grids;    Time-dependent hartree-fock;    Topological analysis;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/665/1/012074/pdf
DOI  :  10.1088/1742-6596/665/1/012074

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

We present simulations of neutron-rich matter at sub-nuclear densities, like supernova matter. With the time-dependent Hartree-Fock approximation we can study the evolution of the system at temperatures of several MeV employing a full Skyrme interaction in a periodic three-dimensional grid [1]. The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. The matter evolves into spherical, rod-like, connected rod-like and slab-like shapes. Further we observe gyroid-like structures, discussed e.g. in [2], which are formed spontaneously choosing a certain value of the simulation box length. The ρ-T-map of pasta shapes is basically consistent with the phase diagrams obtained from QMD calculations [3]. By an improved topological analysis based on Minkowski functionals [4], all observed pasta shapes can be uniquely identified by only two valuations, namely the Euler characteristic and the integral mean curvature. In addition we propose the variance in the cell-density distribution as a measure to distinguish pasta matter from uniform matter.