Energy surface for a spin mapped onto a sphere, showing local minima (blue) separated by energy ridges. Black x’s are first order saddle points. Red curves are saddle point search paths.

From the article:

Duplication, Collapse, and Escape of Magnetic Skyrmions Revealed Using a Systematic Saddle Point Search Method
Gideon P. Müller, Pavel F. Bessarab, Sergei M. Vlasov, Fabian Lux, Nikolai S. Kiselev, Stefan Blügel, Valery M. Uzdin, and Hannes Jónsson
Phys. Rev. Lett. 121, 197202 (2018)

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