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arXiv · 2303.18151

Microscopic calculation of the pinning energy of a vortex in the inner crust of a neutron star

P. Klausner·F. Barranco·P. M. Pizzochero·X. Roca-Maza·E. Vigezzi
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Abstract

The structure of a vortex in the inner crust of a pulsar is calculated microscopically in the Wigner-Seitz cell approximation, simulating the conditions of the inner crust of a cold, non-accreting neutron star, in which a lattice of nuclei coexists with a sea of superfluid neutrons. The calculation is based on the axially deformed Hartree-Fock-Bogolyubov framework, using effective interactions. The present work extends and improves previous studies in four ways: i) it allows for the axial deformation of protons induced by the large deformation of neutrons due to the appearance of vortices; ii) it includes the effect of Coulomb exchange; iii) considers the possible effects of the screening of the pairing interaction; and iv) it improves the numerical treatment. We also demonstrate that the binding energy of the nucleus-vortex system can be used as a proxy to the pinning energy of a vortex and discuss in which conditions this applies. From our results, we can estimate the mesoscopic pinning forces per unit length acting on vortices. We obtain values ranging between $10^{14}$ to $10^{16}$ dyn/cm, consistent with previous findings.

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P. Klausner, F. Barranco, P. M. Pizzochero, X. Roca-Maza, E. Vigezzi. 2023-03-31. Microscopic calculation of the pinning energy of a vortex in the inner crust of a neutron star. https://doi.org/10.1103/physrevc.108.035808

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