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Stability of point defects of degree \(\pm \frac{1}{2}\) in a two-dimensional nematic liquid crystal model. (English) Zbl 1353.82076

Summary: We study \(k\)-radially symmetric solutions corresponding to topological defects of charge \(\frac{k}{2}\) for integer \(k\neq 0\) in the Landau-de Gennes model describing liquid crystals in two-dimensional domains. We show that the solutions whose radial profiles satisfy a natural sign invariance are stable when \(|k| = 1\) (unlike the case \(|k| > 1\) which we treated before). The proof crucially uses the monotonicity of the suitable components, obtained by making use of the cooperative character of the system. A uniqueness result for the radial profiles is also established.

MSC:

82D30 Statistical mechanics of random media, disordered materials (including liquid crystals and spin glasses)
35A15 Variational methods applied to PDEs
35B38 Critical points of functionals in context of PDEs (e.g., energy functionals)
49J10 Existence theories for free problems in two or more independent variables
49J30 Existence of optimal solutions belonging to restricted classes (Lipschitz controls, bang-bang controls, etc.)
76A15 Liquid crystals

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