Second Hubble slow-roll parameter
= Second Hubble slow-roll parameter
{title2=$\eta$}
Using the e-fold variable $N=\log a$, define
$$
\eta=\frac{d\log\epsilon}{dN}.
$$
= Second Hubble slow-roll parameter
{title2=$\eta$}
Using the e-fold variable $N=\log a$, define
$$
\eta=\frac{d\log\epsilon}{dN}.
$$