Comment on "Scaling of the linear response in simple aging systems without disorder"

TL;DR

This paper revisits previous simulations of ferromagnetic systems' susceptibility, clarifying that the decay exponent matches the linear response exponent, contrary to earlier claims, by analyzing the underlying assumptions.

Contribution

It demonstrates that the susceptibility decay exponent equals the linear response exponent, correcting prior misinterpretations and clarifying the assumptions involved.

Findings

Exponent A equals exponent a in susceptibility decay.

Contradicts previous claim that A < a.

Clarifies assumptions in the original analysis.

Abstract

We have repeated the simulations of Henkel, Paessens and Pleimling (HPP) [Phys.Rev.E {\bf 69}, 056109 (2004)] for the field-cooled susceptibility $\chi_{FC}(t) - \chi_0 \sim t^{-A}$ in the quench of ferromagnetic systems to and below $T_C$. We show that, contrary to the statement made by HPP, the exponent $A$ coincides with the exponent $a$ of the linear response function $R(t,s) \sim s^{-(1+a)}f_R(t/s)$. We point out what are the assumptions in the argument of HPP that lead them to the conclusion $A<a$.