The continuum limit of the Poland-Scheraga DNA denaturation model

TL;DR

This paper derives the phase diagram of long DNA using a field theory equivalent to the Poland-Scheraga model, revealing two fixed points with different transition types influenced by excluded volume effects.

Contribution

It provides a closed-form phase diagram for DNA denaturation and identifies two fixed points with distinct transition behaviors through renormalization group analysis.

Findings

Identifies two stable fixed points with different phase transition orders.

Shows the role of excluded volume effects at both fixed points.

Derives the phase diagram in closed form for long DNA molecules.

Abstract

Using a field theory equivalent to a lattice version of the Poland-Scheraga (PS) model, the phase diagram for a long DNA molecule is derived in closed form. A one-loop renormalization group calculation for the generalized PS model with excluded volume interactions shows that there are two stable fixed points. At both fixed points, the excluded volume effect plays a role. At the fixed point reached when the original excluded volume effect is weak, the phase transition is continuous. At the other fixed point, the phase transition is first order.