Implication of the island rule for inflation and primordial perturbations
Yun-Song Piao
Abstract
It is usually thought that the $e$-folds number of inflation must be bounded by its de Sitter entropy, otherwise we will have an information paradox. However, in light of the island rule for computing the entanglement entropy, we show that such a bound might be nonexistent, while the information flux of primordial perturbation modes the observer after inflation is able to detect follows a Page curve. In corresponding eternally inflating spacetime, it seems that our slow-roll inflation patch is accompanied with a neighborly collapsed patch (eventually developing into a black hole) so that its Hawking radiation might be just our primordial perturbations. Accordingly, the perturbation spectrum we observed will present a ``Page-like'' suppression at large scale.