Sarah Koch

Department of Mathematics
120B Malott Hall
Cornell University
Ithaca NY 14853

phone: (607) 255-7548

email: kochs at math.cornell.edu

Curriculum Vitæ



See my new webpage.

Welcome!

I just finished my PhD in the mathematics department at Cornell University, where my advisor was John H. Hubbard. I will spend 2008-2009 in Europe at the University of Warwick as an NSF postdoc. From 2009-2013, I will be at Harvard University as a Benjamin Peirce assistant professor/NSF postdoc. I spent 2006-2007 studying in Marseille, France, where I wrote a different thesis and became a docteur de mathématiques with a doctorate from the Université de Provence in May 2007.


Research:

My research involves a brand new connection between Teichmüller theory and complex dynamics that arose from a special construction in the solution of the "twisted rabbit" problem. Inspired by Thurston's theorem of the characterization of rational maps, John H. Hubbard posed the twisted rabbit problem about 25 years ago; this problem was recently solved by Laurent Bartholdi and Volodia Nekrashevych using iterated monodromy groups in this paper.

A key part of their solution contains the construction of a map on a certain moduli space. My research focuses on generalizing this construction, which leads to very interesting maps. For example, in some cases, these maps extend to post-critically finite endomorphisms of complex projective space; the methods in my French thesis provide a new and systematic way to generate them. We can exploit the fact that these maps were found in the context of Teichmüller theory, providing a wealth of tools with which to understand their dynamics. These maps have also led to a deeper understanding of some of the Teichmüller theory involved.


Papers:

Calculating the iterated monodromy group of a map on $\P^2$, (with J. Belk), in preparation

Slow matings and twisted matings, (with X. Buff, A. Epstein, J. H. Hubbard), in preparation

Teichmüller theory and endomorphisms of $\P^n$, in preparation

On Thurston's Pullback Map, (with X. Buff, A. Epstein, K. Pilgrim), to appear in: Complex Dynamics, Families and Friends, in honor of John H. Hubbard's 60th Birthday

SaddleDrop: a tool for studying dynamics in $\C^2$, submitted


Movies:

This research has led to "slow matings". We form a skew product where the base map is the map on moduli space, and the map in the fiber is a rational map on $\P^1$. If we look in the fiber of this skew product we see evidence of slow mating for some special examples. To see some movies of slow mating, look here. For a more detailed explanation, see the paper 'Slow matings and twisted matings.'


Links:

Dynamics seminar
fun photos

pendulum 1