“…More precisely, they established the first Gaussian fluctuation result for the spatial integral of the solution to a stochastic nonlinear heat equation driven by space-time Gaussian white noise. Since then, we have witnessed a rapidly growing literature on similar CLT results for heat equations with various Gaussian homogeneous noises; see, for example, [26,42,10,11,12,1,41,44,51,36]. Meanwhile, such a program was carried out by Nualart, the second author, and their collaborators to investigate the stochastic nonlinear wave equation driven by Gaussian noises; see [20,8,44,43,6].…”