Universal break law for a class of models of polymer rupture

We model a polymer by a finite chain of Brownian particles, interacting through a pairwise potential U. We investigate what happens when one end of the chain is fixed and the other end slowly pulled away, and when we assume that the chain breaks as soon as the distance between two neighbouring particles exceeds a certain threshold b. We find that under natural conditions on U and suitable scaling of noise and pulling speed, the laws of the break time and of the place along the chain where the break occurs converge to explicit limits. These limits are universal in the sense that they only depend on U”(b).