The BCS-Bogoliubov gap equation with external magnetic field and the first-order phase transition

Fuente: arXiv
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Main Author: Watanabe, Shuji
Format: Preprint
Published: 2025
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author Watanabe, Shuji
author_facet Watanabe, Shuji
contents We deal with a type I superconductor in a constant external magnetic field. We obtain the BCS-Bogoliubov gap equation with external magnetic field and apply the implicit function theorem to it. We show that there is a unique magnetic field (the critical magnetic field) given by a smooth function of the temperature and that there is also a unique nonnegative solution (the gap function) given by a smooth function of both the temperature and the external magnetic field. Using the grand potential, we show that the transition from the normal state to the superconducting state in a type I superconductor is of the first order. Moreover we obtain the explicit expression for the entropy gap.
format Preprint
id arxiv_https___arxiv_org_abs_2501_12609
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The BCS-Bogoliubov gap equation with external magnetic field and the first-order phase transition
Watanabe, Shuji
Mathematical Physics
Superconductivity
We deal with a type I superconductor in a constant external magnetic field. We obtain the BCS-Bogoliubov gap equation with external magnetic field and apply the implicit function theorem to it. We show that there is a unique magnetic field (the critical magnetic field) given by a smooth function of the temperature and that there is also a unique nonnegative solution (the gap function) given by a smooth function of both the temperature and the external magnetic field. Using the grand potential, we show that the transition from the normal state to the superconducting state in a type I superconductor is of the first order. Moreover we obtain the explicit expression for the entropy gap.
title The BCS-Bogoliubov gap equation with external magnetic field and the first-order phase transition
topic Mathematical Physics
Superconductivity
url https://arxiv.org/abs/2501.12609