Fibre Inflation and $\alpha$-attractors

Understand

Fibre inflation is a specific string theory construction based on the Large Volume Scenario that produces an inflationary plateau.

• We outline its relation to $\alpha$-attractor models for inflation, with the cosmological sector originating from certain string theory corrections leading to $\alpha=2$ and $\alpha=1/2$.
• Above a certain field range, the steepening effect of higher-order corrections leads first to the breakdown of single-field slow-roll and after that to the onset of 2-field dynamics: the overall volume of the extra dimensions starts to participate in the effective dynamics.
• Finally, we propose effective supergravity models of fibre inflation based on an ${\overline {D3}}$ uplift term with a nilpotent superfield.