Critical phenomena of RNA-like polymers -- a synopsis

TL;DR

This paper explores the critical behavior of RNA-like polymers using field theories derived from lattice models, revealing new critical exponents and the impact of base sequence randomness on polymer phase transitions.

Contribution

It introduces a novel analysis of RNA-like polymer critical phenomena, linking them to Lee-Yang theory and identifying additional critical exponents due to base sequence effects.

Findings

Critical point of RNA-like branched polymers resembles classical branched polymers.

RNA-like polymers exhibit an extra critical exponent for single strands.

Random base sequences introduce relevant interactions, complicating the critical behavior.

Abstract

This work examines field theories for RNA-like polymers with single strand and double strand polymers and a periodic base sequence. These field theories originate from lattice models, describe polymers in a good solvent, and in principle exactly describe the critical behavior. A central role is played by the conventional one-component branched polymer and the mapping of the corresponding field theory to the Lee-Yang field theory in two less dimensions. Critical phenomena in the context of polymers as well as the Lee-Yang model entail pecularities, which we derive in detail. A new result is that the critical point of RNA-like branched polymers (with periodic base sequence) looks like the critical point of the classical one-component branched polymer, but with one more critical exponent for the single strand polymer. A random base sequence generates additional relevant interactions, and invalidates the simple picture.