Comment on "More Axions from Strings''

TL;DR

This paper refutes a recent claim that axion strings exhibit a logarithmic increase in density, demonstrating that their behavior aligns with the standard scaling expectation through analysis and modeling.

Contribution

The authors clarify that the observed data are consistent with standard string scaling, countering claims of logarithmic growth and providing explanations via standard network modeling.

Findings

String density data are consistent with standard scaling.

Transient slow growth explained by network modeling.

No violation of the standard scaling expectation.

Abstract

We comment on a claim that axion strings show a long-term logarithmic increase in the number of Hubble lengths per Hubble volume [arXiv:2007.04990], thereby violating the standard "scaling" expectation of an O(1) constant. We demonstrate that the string density data presented in [arXiv:2007.04990] are consistent with standard scaling, at a string density consistent with that obtained by us [arXiv:1908.03522, arXiv:2102.07723] and other groups. A transient slow growth in Hubble lengths per Hubble volume towards its constant scaling value is explained by standard network modelling [arXiv:2102.07723].