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arXiv · 2507.13597

Equation of state of spin-polarized nuclear matter in the relativistic Hartree-Fock method

Toi Tachibana·Kouichi Hagino·Kenichi Yoshida·Qiang Zhao
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Abstract

We calculate the equation of state (EOS) of spin-polarized nuclear matter in the relativistic Hartree-Fock method. To this end, we employ the relativistic point-coupling model, with which the Fock terms are considerably simplified, reducing them to the same form as the Hartree terms. In analogy to the slope parameter $L$ of the isospin-symmetry energy for spin-unpolarized matter, we evaluate the spin slope parameter $L_s$ of the corresponding spin-symmetry energy for spin-polarized matter. We find that the slope parameter $L$ and the spin slope parameter $L_s$ have a negative correlation in the case of isoscalar polarization, where neutrons and protons are spin-polarized in the same direction. On the other hand, the spin slope parameter is nearly independent of the slope parameter in the case of isovector polarization, where neutrons are spin-polarized along the opposite direction to protons. We show that these correlations are a natural consequence of the relativistic point coupling model which we employ.

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Toi Tachibana, Kouichi Hagino, Kenichi Yoshida, Qiang Zhao. 2025-07-18. Equation of state of spin-polarized nuclear matter in the relativistic Hartree-Fock method. https://arxiv.org/abs/2507.13597

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