Special Seminar

Title: Failure of Ergodicity in a (Rational) Billiard
Speaker: Yitwah Cheung
Speaker Info: UIC
Brief Description:
Special Note:

Abstract: The straight line flow on a flat surface includes the dynamics of rational billiards and interval exchanges as special cases. In this talk I will describe 1-parameter families of dynamical systems which can all be viewed as flows on certain flat surfaces. In particular, we will see that certain number theoretic conditions on the parameter will determine whether or not the system will have orbits which are not uniformly distributed. As an application, we will see that the 2-by-1 rectangular billiard table with a barrier of length sqrt(2)-1 extending perpendicularly from the midpoint of a longer side has an uncountable set of directions in which the billiard ball can be shot so that it spends an unequal amount of time on the two sides of the table.

Date: Friday, February 4, 2000
Time: 4:10pm
Where: Lunt 105
Contact Person: Prof. Keith Burns
Contact email: burns@math.nwu.edu
Contact Phone: 847-491-3013
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