Probability Seminar: An isomorphism theorem anharmonic fields and scaling limits

Seminar | March 22 | 3:10-4 p.m. | 340 Evans Hall

Speaker/Performer:  Jean-Dominique Deuschel, Technische Universität Berlin

Sponsor:  Department of Statistics

We introduce a natural measure on bi-infinite random walk trajectories evolving in a time-dependent environment driven by the Langevin dynamics associated to a gradient Gibbs measure with convex potential. We derive an identity relating the occupation times of the Poissonian cloud induced by this measure to the square of the corresponding gradient field, which is not Gaussian. In the quadratic case, we recover a well-known generalization of the second Ray-Knight theorem. We further determine the scaling limits of the various objects involved in dimension 3, which are seen to exhibit homogenization. In particular, we prove that the renormalized square of the gradient field converges under appropriate rescaling to the Wick-ordered square of a Gaussian free field on R3 with suitable diffusion matrix, thus extending a celebrated result of Naddaf and Spencer regarding the scaling limit of the field itself.

This is joint work with Pierre-Francois Rodriguez.

Event Contact:  alanmhammond@yahoo.co.uk, 510-0000000

Access Coordinator:  Alan Hammond,  alanmhammond@yahoo.co.uk,  510-000-0000