arXiv subjects

Dale Winter

Publications and source records attributed to Dale Winter.

7 recordsLinked to original sources

arXiv2020

Exponential mixing of frame flows for convex cocompact hyperbolic manifolds

The aim of this paper is to establish exponential mixing of frame flows for convex cocompact hyperbolic manifolds of arbitrary dimension with respect to the Bowen-Margulis-Sullivan measure. Some immediate applications include an asymptotic formula for matrix coefficients with an exponential error term as well as the exponential equidistribution of holonomy of closed geodesics. The main technical result is a spectral bound on transfer operators twisted by holonomy, which we obtain by building on Dolgopyat's method.

math.DS↗

arXiv2017

Uniform congruence counting for Schottky semigroups in $\mathrm{SL}_2(\mathbf{Z})$

Let $Γ$ be a Schottky semigroup in $\mathrm{SL}_2(\mathbf{Z})$, and for $q\in \mathbf N$, let $Γ(q):=\{γ\in Γ: γ= e \text{ (mod $q$)}\}$ be its congruence subsemigroup of level $q$. We prove the following uniform congruence counting theorem with respect to the family of Euclidean norm balls $B_R$ in $M_2(\mathbf{R})$ of radius $R$: for all $q$ with no small prime factors, $ (Γ(q) \cap B_R )= c_Γ\frac{R^{2δ}}{ (\mathrm{SL}_2(\mathbf{Z}/q\mathbf{Z}))} +O(q^C R^{2δ-ε})$ as $R\to \infty$ for some $c_Γ>0, C>0, ε>0$ which are independent of $q$. Our technique also applies to give a similar counting result for the continued fractions semigroup of $\mathrm{SL}_2(\mathbf{Z})$, which arises in the study of Zaremba's conjecture on continued fractions.

math.NT↗

arXiv2016

Exponential Mixing of Frame Flow for Convex Cocompact Hyperbolic Manifolds

The aim of this paper is to establish exponential mixing of frame flow for the measure of maximal entropy on a convex cocompact hyperbolic manifold. Consequences include results on the decay of matrix coefficients and on effective equidistribution of holonomies. The main technical point is a spectral bound on certain twisted transfer operators, which we obtain by building on Dolgopyat's framework. This extends and strengthens earlier work of Dolgopyat, Stoyanov, Pollicott, and others.

math.DS↗

arXiv2016

Prime number theorems and holonomies for hyperbolic rational maps

We discuss analogues of the prime number theorem for a hyperbolic rational map f of degree at least two on the Riemann sphere. More precisely, we provide counting estimates for the number of primitive periodic orbits of f ordered by their multiplier, and also obtain equidistribution of the associated holonomies; both estimates have power savings error terms. Our counting and equidistribution results will follow from a study of dynamical zeta functions that have been twisted by characters of $S^1$. We will show that these zeta functions are non-vanishing on a half plane $\Re(s) > δ- ε$, where $δ$ is the Hausdorff dimension of the Julia set of f.

math.DS↗

arXiv2015

Uniform exponential mixing and resonance free regions for convex cocompact congruence subgroups of $\operatorname{SL}_2(\mathbb{Z})$

Let $Γ<\mathrm{SL}_2(\mathbb{Z})$ be a non-elementary finitely generated subgroup and let $Γ(q)$ be its congruence subgroup of level $q$ for each $q\in \mathbb{N}$. We obtain an asymptotic formula for the matrix coefficients of $L^2(Γ(q) \backslash \mathrm{SL}_2(\mathbb{R}))$ with a {\it uniform} exponential error term for all square-free $q$ with no small prime divisors. As an application we establish a uniform resonance-free half plane for the resolvent of the Laplacian on $Γ(q) \backslash \mathbb{H}^2$ over $q$ as above. Our approach is to extend Dolgopyat's dynamical proof of exponential mixing of the geodesic flow uniformly over congruence covers, by establishing uniform spectral bounds for congruence transfer operators associated to the geodesic flow. One of the key ingredients is the expander theory due to Bourgain-Gamburd-Sarnak.

math.DS↗

arXiv2015

Expanding maps and continued fractions

We obtain a power saving in the error term for a semigroup congruence lattice point count related to continued fractions. This is done by adapting arguments from recent work of Oh and Winter (2014) that give uniform bounds for certain transfer operators in the congruence aspect. Our arguments also build crucially on work of Naud (2005) and Bourgain, Gamburd and Sarnak (2011). The result we obtain, together with a certain conjecture about the multiplicative combinatorics of $\mathrm{SL}_2(\mathbf{Z})$ that we highlight in the sequel, can be used to obtain an improvement on the size of the exceptional set in Bourgain and Kontorovich's work (2014) on Zaremba's conjecture.

math.NT↗

arXiv2014

Mixing of frame flow for rank one locally symmetric spaces and measure classification

Let $G$ be a connected simple linear Lie group of rank one, and let $Γ<G$ be a discrete Zariski dense subgroup admitting a finite Bowen-Margulis-Sullivan measure $m^{\operatorname{BMS}}$. We show that the right translation action of the one dimensional diagonalizable subgroup is mixing on $(Γ\backslash G, m^{\operatorname{BMS}})$. Together with the work of Roblin, this proves ergodicity of the Burger-Roblin measure under the horospherical group $N$, establishes a classification theorem for $N$ invariant Radon measures on $Γ\backslash G$, and provides precise asymptotics for the Haar measure matrix coefficients.

math.DS↗