Nuclear band theory of neutron star crust



The inner crust of a neutron star is formed of a crystal lattice of nuclear clusters immersed in a neutron sea. This nuclear environment is closely analogous to more familiar periodic systems in condensed matter, like for instance electrons in ordinary metals, atomic Bose gases in optical lattices, photonic or phononic crystals. All these periodic systems are described by the band theory of solids developed by Felix Bloch.


I started a few years ago to adapt for the first time this theory to neutron star crust. The band theory allows a consistent treatment of both the free neutrons and the nucleons bound inside nuclear clusters. The figure below shows an example of a numerical calculation of the neutron band structure (left) and the corresponding Fermi surface (right), at a density of 700 billion grams per cubic centimeters. The crust is composed of a body centered cubic lattice of zirconium like clusters (40 protons per lattice site). The different colors are associated with different branches of the Fermi surface. 

neutron band structureneutron Fermi surface


see Chamel, Nucl. Phys. A747(2005), 109.
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