Running of the scalar spectral index
= Running of the scalar spectral index
{title2=$\alpha_s=dn_s/d\log k\simeq16\epsilon_V\eta_V-24\epsilon_V^2-2\xi_V^2$}
The running describes the scale dependence of the <scalar spectral index>. Differentiating $n_s-1\simeq-6\epsilon_V+2\eta_V$ with the <potential slow-roll flow equations> gives the displayed second-order slow-roll result. It includes the <third potential slow-roll parameter> and is generally smaller than the leading spectral tilt.