A recent study explores curvaton dynamics beyond standard models, revealing how self-interactions of this field can generate strongly non-Gaussian curvature perturbations after cosmic inflation. These perturbations, deviating from a simple random distribution, have significant implications for the formation of small-scale structures in the early universe. Researchers have developed a formalism that connects the frozen and oscillatory regimes of the curvaton, exposing sources of non-Gaussianity not observed in the purely quadratic case.

The team applied this formalism to various potentials (quadratic, monomial, quartic, and cosine), demonstrating that curvaton self-interactions can either enhance or suppress the resulting non-Gaussianity, depending on the potential and initial conditions. This analysis includes non-perturbative aspects in the strongly non-Gaussian regime, showing how strong non-Gaussianity can even suppress the power spectrum of primordial fluctuations. This is crucial for understanding the distribution of matter in the early universe.

As a practical application, the study proposes a scenario where strong positive curvaton non-Gaussianity could seed supermassive primordial black holes. These objects, with peak amplitudes of approximately 10^-5, would be compatible with constraints imposed by COBE/FIRAS μ-distortion observations of the cosmic microwave background. This mechanism offers a primordial explanation for the "Little Red Dots" observed by the James Webb Space Telescope (JWST), suggesting that the oldest supermassive black holes might have a cosmological origin rather than forming from stellar collapse. An axion-like curvaton is presented as a natural candidate for this mechanism.