Yang–Lee zeros and the helix–coil transition in a continuum model of polyalanine

We calculate the Yang–Lee zeros for characteristic temperatures of the helix–coil transition in a continuum model of polyalanine. The distribution of these zeros differs from predictions of the Zimm–Bragg theory and supports recent claims that polyalanine exhibits a true phase transition. New estimates for critical exponents are presented and the relation of our results to the Lee–Yang theorem is discussed