Number of e-folds
= Number of e-folds
{title2=$N=\log(a/a_i)$}
The number of e-folds during an interval of expansion is the logarithmic growth of the <scale factor>:
$$
N=\log\frac{a_f}{a_i}=\int_{t_i}^{t_f}H\,dt.
$$
= Number of e-folds
{title2=$N=\log(a/a_i)$}
The number of e-folds during an interval of expansion is the logarithmic growth of the <scale factor>:
$$
N=\log\frac{a_f}{a_i}=\int_{t_i}^{t_f}H\,dt.
$$