The asymmetry of Thurston's earthquake flow

Abstract

We show that Thurston's earthquake flow is strongly asymmetric in the sense that its normalizer is as small as possible inside the group of orbifold automorphisms of the bundle of measured geodesic laminations over moduli space. (At the level of Teichmüller space, such automorphisms correspond to homeomorphisms that are equivariant with respect to an automorphism of the mapping class group.) It follows that the earthquake flow does not extend to an $\mathrm{SL}(2,\mathbf{R})$-action of orbifold automorphisms and does not admit continuous renormalization self-symmetries. In particular, it is not conjugate to the Teichmüller horocycle flow via an orbifold map. This contrasts with a number of previous results, most notably Mirzakhani's theorem that the earthquake and Teichmüller horocycle flows are measurably conjugate.

17 pages, 2 figures. Expanded introduction, references, and some proofs

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Cited by in corpus (2)

• Shear-shape cocycles for measured laminations and ergodic theory of the earthquake flow
• Continuity of the orthogeodesic foliation and ergodic theory of the earthquake flow