Comment on "Anomalous Discontinuity at the Percolation Critical Point of Active Gels"

TL;DR

This paper critiques the no-enclaves percolation (NEP) model, arguing that its Fisher exponent is exactly 2, aligning with random percolation, and therefore it does not form a new universality class as previously claimed.

Contribution

The authors demonstrate that the Fisher exponent for NEP is exactly 2, refuting prior claims of a distinct universality class from random percolation.

Findings

Fisher exponent for NEP is exactly 2

NEP's properties are consistent with random percolation

No new universality class is established by NEP

Abstract

In their recent work Sheinman et al. [Phys. Rev. Lett. 114, 098104 (2015)] introduce a variation of percolation which they call no-enclaves percolation (NEP). The main claims are 1) the salient physics captured in NEP is closer to what happens experimentally; 2) The Fisher exponent of NEP, is $\tau=1.82(1)$; 3) Due to the different Fisher exponent, NEP constitutes a universality class distinct from random percolation (RP). While we fully agree with 1) and found NEP to be a very interesting variation of random percolation, we disagree with 2) and 3). We will demonstrate that $\tau$ is exactly $2$, directly derivable from RP, and thus there is no foundation of a new universality class.