From new to large‐field inflation

We briefly summarize and update a class of inflationary models from the early eighties based on a quartic (Coleman‐Weinberg) potential for a gauge singlet scalar (inflaton) field. For vacuum energy scales comparable to the grand unification scale, the scalar spectral index n_s ≃ 0.94–0.97, in very good agreement with the WMAP three year results. The tensor to scalar ratio r ≲ 0.14 while α ≡ dn_s/d ln k is ≃ −10⁻³. For vacuum energy scales ≳ 10¹⁶ GeV, the inflationary scenario switches from ‘new’ to ‘large‐field’ (V ∝ φ²) inflation. An SO(10) version naturally explains the observed baryon asymmetry via non‐thermal leptogenesis.