Time-Dependent Slef-Consistent Band Theory for the Inner Crust of Neutron Stars: Anti-Entrainment Effects in the Slab Phase
ORAL
Abstract
In the inner crust of neutron stars, a variety of crystalline structures emerge, which are immersed in a sea of dripped neutrons. The dripped neutrons extend spatially, feeling crystalline, periodic nuclear potentials. The situation resembles the one encountered in terrestrial materials, where electrons are under a periodic potential of an ionic Coulomb lattice. Needless to say, one has to work with the band theory of solids to explain diverse properties of materials, e.g., if it is a metal, an insulator, or a semi-conductor. In the same way, to correctly assess properties of conduction neutrons in the inner crust of neutron stars, the use of the band theory of solids is mandatory.
The application of the band theory in the context of neutron stars started only in 2005 [1, 2]. In Ref. [1,2], it has been shown that conduction neutron number density is reduced by Bragg scatterings of dripped neutrons off the periodic potential, leading to increase of the neutron effective mass, which is called "entrainment effect." Moreover, it has been advocated that the neutron effective mass could be more than 10 times larger than the bare neutron mass in some density region [2], which affects interpretations of various astrophysical phenomena. On the other hand, recent fully self-consistent band theory calculations [3] indicate that the neutron effective mass could be reduced at least for the slab phase.
To resolve the debatable situation, we are developing fully self-consistent time-dependent band theory for the inner crust of neutron stars based on time-dependent density functional theory (TDDFT) [4, 5]. In this contribution, we present the outcomes of the first application to the slab phase [4], where we propose an intuitive, real-time method to dynamically quantify the entrainment effect, showing a reduction of the neutron effective mass, identifying an "anti-entrainment" phenomenon in the slab phase.
[1] B. Carter, N. Chamel, and P. Haensel, Nucl. Phys. A748, 675 (2005).
[2] N. Chamel, Nucl. Phys. A773, 263 (2005).
[3] Yu Kashiwaba and T. Nakatsukasa, Phys. Rev. C 100, 035804 (2019).
[4] K. Sekizawa, S. Kobayashi, and M. Matsuo, Phys. Rev. C 105, 045807 (2022).
[5] K. Yoshimura and K. Sekizawa, arXiv:2306.03327 [nucl-th].
The application of the band theory in the context of neutron stars started only in 2005 [1, 2]. In Ref. [1,2], it has been shown that conduction neutron number density is reduced by Bragg scatterings of dripped neutrons off the periodic potential, leading to increase of the neutron effective mass, which is called "entrainment effect." Moreover, it has been advocated that the neutron effective mass could be more than 10 times larger than the bare neutron mass in some density region [2], which affects interpretations of various astrophysical phenomena. On the other hand, recent fully self-consistent band theory calculations [3] indicate that the neutron effective mass could be reduced at least for the slab phase.
To resolve the debatable situation, we are developing fully self-consistent time-dependent band theory for the inner crust of neutron stars based on time-dependent density functional theory (TDDFT) [4, 5]. In this contribution, we present the outcomes of the first application to the slab phase [4], where we propose an intuitive, real-time method to dynamically quantify the entrainment effect, showing a reduction of the neutron effective mass, identifying an "anti-entrainment" phenomenon in the slab phase.
[1] B. Carter, N. Chamel, and P. Haensel, Nucl. Phys. A748, 675 (2005).
[2] N. Chamel, Nucl. Phys. A773, 263 (2005).
[3] Yu Kashiwaba and T. Nakatsukasa, Phys. Rev. C 100, 035804 (2019).
[4] K. Sekizawa, S. Kobayashi, and M. Matsuo, Phys. Rev. C 105, 045807 (2022).
[5] K. Yoshimura and K. Sekizawa, arXiv:2306.03327 [nucl-th].
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Publication: [1] K. Sekizawa, S. Kobayashi, and M. Matsuo, Time-dependent extension of the self-consistent band theory for neutron star matter: Anti-entrainment effects in the slab phase, Phys. Rev. C 105, 045807 (2022).
Presenters
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Kazuyuki Sekizawa
Tokyo Institute of Technology
Authors
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Kazuyuki Sekizawa
Tokyo Institute of Technology
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Kenta Yoshimura
Tokyo Institute of Technology
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Masayuki Matsuo
Niigata University