Pathways Workshop: Topological and Geometric Structures in Low Dimensions & Geometry and Dynamics for Discrete Subgroups of Higher Rank Lie Groups: Double exponential mixing in analytic dynamics
Presenter
January 23, 2026
Keywords:
- low-dimensional topology
- geometric structures
- homogeneous dynamics
- Anosov representations
- Higher rank Lie groups
- symmetric spaces of non- compact type
MSC:
- 57M50 - General geometric structures on low-dimensional manifolds
- 57M60 - Group actions on manifolds and cell complexes in low dimensions
- 57N16 - Geometric structures on manifolds of high or arbitrary dimension
- 57S25 - Groups acting on specific manifolds
- 22E40 - Discrete subgroups of Lie groups
- 22F30 - Homogeneous spaces
- 37E05 - Dynamical systems involving maps of the interval
- 37E10 - Dynamical systems involving maps of the circle
- 37E30 - Dynamical systems involving homeomorphisms and diffeomorphisms of planes and surfaces
- 37E35 - Flows on surfaces
- 30F60 - Teichmüller theory for Riemann surfaces
- 32G15 - Moduli of Riemann surfaces
- Teichmüller theory (complex-analytic aspects in several variables)]
- 30F40 - Kleinian groups (aspects of compact Riemann surfaces and uniformization)
Abstract
In dynamics, the speed of mixing depends on the dynamical features of the map and the regularity of the observables. Notably, two classical linear models—the Bernoulli doubling map and the CAT map—exhibit double exponential mixing for analytic observables. Are ergodic linear maps the only ones with this property? In dimension one, we provide a full classification for maps from the space of volume-preserving finite Blaschke products acting on the circle (as well as for free semigroup actions generated by a finite collection of such maps). In higher dimensions, we identify a necessary condition for double exponential mixing and present several families of examples and non-examples. Key ideas of the proof involve the Koopman precomposition operator on spaces of hyperfunctions (elements of the dual space of analytic functions), which turns out to be non-self-adjoint, compact, and quasi-nilpotent, with spectrum reduced to zero.