We reconsider a toy model of topological inflation, based on the R 4-modified gravity. By using its equivalence to a certain scalar-tensor gravity model in four spacetime dimensions, we compute the inflaton scalar potential and investigate the possibility of inflation. We confirm the existence of slow-roll inflation with an exit. However, the model suffers from the η-problem that gives rise to the unacceptable value of the spectral index ns of scalar perturbations.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)