Chaotic inflation, radiative corrections and precision cosmology

We employ chaotic (ϕ2ϕ2 and ϕ4ϕ4) inflation to illustrate the important role radiative corrections can play during the inflationary phase. Yukawa interactions of ϕ  , in particular, lead to corrections of the form −κϕ4ln(ϕ/μ)−κϕ4ln(ϕ/μ), where κ>0κ>0 and μ   is a renormalization scale. For instance, ϕ4ϕ4 chaotic inflation with radiative corrections looks compatible with the most recent WMAP (5 year) analysis, in sharp contrast to the tree level case. We obtain the 95% confidence limits 2.4×10−14≲κ≲5.7×10−142.4×10−14≲κ≲5.7×10−14, 0.931≲ns≲0.9580.931≲ns≲0.958 and 0.038≲r≲0.2050.038≲r≲0.205, where nsns and r   respectively denote the scalar spectral index and scalar to tensor ratio. The limits for ϕ2ϕ2 inflation are κ≲7.7×10−15κ≲7.7×10−15, 0.929≲ns≲0.9660.929≲ns≲0.966 and 0.023≲r≲0.1350.023≲r≲0.135. The next round of precision experiments should provide a more stringent test of realistic chaotic ϕ2ϕ2 and ϕ4ϕ4 inflation.