Helix or coil? Fate of a melting heteropolymer

We study the probability that a partially melted heteropolymer at the melting temperature will either melt completely or return to a helix state. This system is equivalent to the splitting probability for a diffusing particle on a finite interval that moves according to the Sinai model. When the initial fraction of melted polymer is g , the melting probability fluctuates between different realizations of monomer arrangements on the chain. For a fixed value of g , the melting probability distribution changes from unimodal to a bimodal as the strength of the disorder is increased.