We revisit the growth of curvature perturbations in non-minimal curvaton scenario with a non-trivial field metric 𝜆(𝜙)  where 𝜙  is an inflaton field, and incorporate the effect from the non-uniform onset of curvaton's oscillation in terms of an axion-like potential. The field metric 𝜆(𝜙)  plays a central role in the enhancement of curvaton field perturbation 𝛿𝜒, serving as an effective friction term which can be either positive or negative, depending on the first derivative 𝛿χ. Our analysis reveals that 𝛿χ undergoes the superhorizon growth which is analogous to the mechanism responsible for the amplification of curvature perturbations in the context of ultra-slow-roll inflation, namely the growing modes dominate curvature perturbations. Utilizing the δN formalism, we derive analytical expressions for both the final curvature power spectrum and the non-linear parameter 𝑓_𝑁𝐿 in terms of an axion-like curvaton's potential leading to the non-uniform curvaton's oscillation.

报告人简介：

Dr. Chao Chen received his PhD in Astrophysics from the University of Science and Technology of China in 2021 before joining HKUST IAS as a Postdoctoral Fellow in the same year. Dr. Chen‘s previous studies cover several aspects of physical cosmology such as inflationary Universe, secondary gravitational waves, primordial black holes and wave dark matter.

邀请人：

皮石 副研究员