Comment on "A new universality class describes Vicsek's flocking phase in physical dimensions''

Abstract

In a recent preprint, ``A new universality class describes Vicsek's flocking phase in physical dimensions'', Patrick Jentsch and Chiu Fan Lee have computed the critical exponents of the Vicsek model in the ordered phase by means of functional renormalization group methods. In this note, we compare their results with our previous theoretical predictions for the Vicsek model, which is expected to be exact in $d=2$ dimensions. We point out that the critical exponents predicted by the two theories are extremely close in both $d=2$ and $3$ dimensions. We found that both theories fit the current numerical data equally well. Extensive numerical simulations for larger system sizes are thus highly desirable to judge which theory is correct.