Large deviations for Brownian intersection measures

Chiranjib Mukherjee
Abstract
We consider a number of independent Brownian motions in a bounded domain in Rd running until time t and look at their intersection set, i.,e. points which are hit by all the motions before time t. There is a measure lt supported on this intersection set which counts the intensity of the intersections and this is called the Brownian intersection measure. We derive large t asymptotics of this measure in terms of a large deviation principle in the set of finite measures on B. The rate function is explicit and gives some direct meaning of the intersection measure as pointwise product of the occupation measures of individual Brownian motions. Our result is in fact an extension of Donsker-Varadhan large deviations to a non-linear setting. This is joint work with Wolfgang Koenig (Berlin).