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On the uniqueness of minimisers of Ginzburg-Landau functionals. (English) Zbl 1445.35011

Summary: We provide necessary and sufficient conditions for the uniqueness of minimisers of the Ginzburg-Landau functional for \(\mathbb{R}^n\)-valued maps under a suitable convexity assumption on the potential and for \(H^{1/2} \cap L^\infty\) boundary data that is non-negative in a fixed direction \(e\in \mathbb{S}^{n-1} \). Furthermore, we show that, when minimisers are not unique, the set of minimisers is generated from any of its elements using appropriate orthogonal transformations of \(\mathbb{R}^n\). We also prove corresponding results for harmonic maps with values into \(\mathbb{S}^{n-1}\).

MSC:

35A02 Uniqueness problems for PDEs: global uniqueness, local uniqueness, non-uniqueness
35B06 Symmetries, invariants, etc. in context of PDEs
35J50 Variational methods for elliptic systems
35Q56 Ginzburg-Landau equations

Keywords:

harmonic maps