Saddle Point Configurations for Spherical Ferromagnets

Fuente: arXiv
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Autori principali: Gustafson, Stephen, Meinert, Daniel, Melcher, Christof
Natura: Preprint
Pubblicazione: 2025
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author Gustafson, Stephen
Meinert, Daniel
Melcher, Christof
author_facet Gustafson, Stephen
Meinert, Daniel
Melcher, Christof
contents We investigate saddle point configurations in spherical ferromagnets with perpendicular anisotropy. These are modeled by a micromagnetic energy functional on the unit sphere that leads to the emergence of the so-called curvature induced Dzyaloshinskii--Moriya interaction. For this functional we establish the existence of two distinct types of saddle points with zero mapping degree. We use a parabolic flow approach inspired by the harmonic map heat flow where for certain highly symmetric initial conditions we can rule out finite and infinite time blowup. Hence, we obtain solutions of the underlying Euler--Lagrange equation in the long time limit. This is in contrast to harmonic maps between two-spheres, where every map is a local minimizer of the energy functional.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05159
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Saddle Point Configurations for Spherical Ferromagnets
Gustafson, Stephen
Meinert, Daniel
Melcher, Christof
Analysis of PDEs
Mathematical Physics
35B38, 58J35, 58E20, 35Q60, 82D40
We investigate saddle point configurations in spherical ferromagnets with perpendicular anisotropy. These are modeled by a micromagnetic energy functional on the unit sphere that leads to the emergence of the so-called curvature induced Dzyaloshinskii--Moriya interaction. For this functional we establish the existence of two distinct types of saddle points with zero mapping degree. We use a parabolic flow approach inspired by the harmonic map heat flow where for certain highly symmetric initial conditions we can rule out finite and infinite time blowup. Hence, we obtain solutions of the underlying Euler--Lagrange equation in the long time limit. This is in contrast to harmonic maps between two-spheres, where every map is a local minimizer of the energy functional.
title Saddle Point Configurations for Spherical Ferromagnets
topic Analysis of PDEs
Mathematical Physics
35B38, 58J35, 58E20, 35Q60, 82D40
url https://arxiv.org/abs/2509.05159