2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/201059We study the renormalized energy-momentum tensor (EMT) of cosmological scalar fluctuations during the slow-rollover regime for chaotic inflation with a quadratic potential and find that it is characterized by a negative energy density which grows during slow-rollover. We also approach the back-reaction problem as a second-order calculation in perturbation theory finding no evidence that the back-reaction of cosmological fluctuations is a gauge artifact. In agreement with the results on the EMT, the average expansion rate is decreased by the back-reaction of cosmological fluctuations.19 pages, no figures.An appendix and references added, conclusions unchanged, version accepted for publication in PRDGeneral Relativity and Quantum CosmologyAstrophysicsHigh Energy Physics - Theorytext