This research reveals examples of rigidity failures in higher rank geometry, indicating limitations of Ratner's theorem.
Ratner's theorem shows that in a locally symmetric space of noncompact type and finite volume, every immersed totally geodesic subspace of noncompact type is topologically rigid: its closure is an immersed submanifold. We construct the first explicit higher-rank, infinite-volume examples in which this rigidity fails, via floating geodesic planes. Specifically, we exhibit a Zariski-dense Hitchin surface group Γ<SL₃(R) such that Γ SL₃(R)/ SO(3) contains a sequence of immersed floating geodesic planes with fractal closures whose Hausdorff dimensions, non-integral, accumulate at $2$. Moreover, $Γ$ can be chosen inside SL₃(Z). Our method uses Goldman's bulging deformations, but in higher rank new difficulties arise: unlike in rank one, where geodesics orthogonal to a hyperplane always diverge, here one must analyze the collective behavior of entire families of parallel geodesics inside flats under bulging, a phenomenon intrinsic to higher rank.
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Dey et al. (2025) studied this question.
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