Non-Gaussian bubbles in the sky

Understand

We point out a possible generation mechanism of non-Gaussian bubbles in the sky due to bubble nucleation in the early universe.

• We consider a curvaton scenario for inflation and assume that the curvaton field phi, whose energy density is subdominant during inflation but which is responsible for the curvature perturbation of the universe, is coupled to another field sigma which undergoes false vacuum decay through quantum tunneling.
• For this model, we compute the skewness of the curvaton fluctuations due to its interaction with sigma during tunneling, that is, on the background of an instanton solution that describes false vacuum decay.
• We find that the resulting skewness of the curvaton can become large in the spacetime region inside the bubble.