Weak-strong uniqueness for the general Ericksen-Leslie system in three dimensions

Abstract: We study the Ericksen-Leslie system equipped with a quadratic free energy functional. The norm restriction of the director is incorporated by a standard relaxation technique using a double-well potential. We use the relative energy concept, often applied in the context of compressible Euler- or related systems of fluid dynamics, to prove weak-strong uniqueness of solutions. A main novelty is that the relative energy inequality is proved for a system with a nonconvex energy.