Introduction to the Number of <i>e</i>-Folds in Slow-Roll Inflation
Alessandro Di Marco,
Emanuele Orazi,
Gianfranco Pradisi
Affiliations
Alessandro Di Marco
Istituto Nazionale di Astrofisica, Istituto di Astrofisica e Planetologia Spaziali (INAF-IAPS), Via Fosso del Cavaliere, 100, 00133 Rome, Italy
Emanuele Orazi
Escola de Ciência e and International Institute of Physics, Federal University of Rio Grande do Norte, Campus Universitario, Lagoa Nova 59078-970, RN, Brazil
Gianfranco Pradisi
Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Roma Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Roma, Italy
In this review, a pedagogical introduction to the concepts of slow-roll inflationary universe and number of e-folds is provided. In particular, the differences between the basic notion of number of e-folds (Ne), total number of e-folds (NT) and number of e-folds before the end of inflation (N) are outlined. The proper application of the number of e-folds before the end of inflation is discussed both as a time-like variable for the scalar field evolution and as a key parameter for computing inflationary predictions.
