Comment on `Glassy Transition in a Disordered Model for the RNA Secondary Structure'

TL;DR

This paper challenges previous claims of replica symmetry breaking in an RNA secondary structure model by demonstrating that, at larger sizes, the overlap distribution converges to a delta function, indicating no symmetry breaking.

Contribution

The study extends the analysis to larger RNA sequence sizes, showing the overlap distribution converges to a delta function, contradicting earlier findings of replica symmetry breaking.

Findings

Variance of overlap distribution tends to zero at larger sizes

Overlap distribution becomes a delta function in the thermodynamic limit

No evidence of replica symmetry breaking at large sizes

Abstract

In cond-mat/9907125 the low-temperature behavior of a model for RNA secondary structure was studied. It is claimed that the model exhibits a breaking of the replica symmetry, since the width of the distribution P(q) of overlaps may converge to a finite value at T=0. The authors used an exact enumeration method to obtain all ground states for a given RNA sequence. Because of the exponential growing degeneracy, only sequences up to length L=256 could be studied. Here it is shown that, in contrast to the previous results, by going to much larger sizes as L=2000 the variance coverges towards zero, i.e. P(q) is a delta-function in the thermodynamic limit.