$\alpha$-attractor-type Double Inflation

Understand

We study the background dynamics and primordial perturbation in $\alpha$-attractor-type double inflation.

• The model is composed of two minimally coupled scalar fields, where each of the fields has a potential of the $\alpha$-attractor type.
• We find that the background trajectory in this double inflation model is given by two almost straight lines connected with a turn in the field space.
• With this simple background, we can classify the property of the perturbations generated in this double inflation model just depending on whether the turn occurs before the horizon exit for the mode corresponding to the scale of interest or not.