An Open Universe from Valley Bounce

TL;DR

This paper proposes a new approach to constructing open universe models using valley bounces, challenging previous assumptions about false vacuum decay and enabling polynomial potentials compatible with observations.

Contribution

It introduces the idea that valley bounces, not Hawking Moss solutions, can describe false vacuum decay, allowing polynomial potentials for open inflation.

Findings

Valley bounces can replace Hawking Moss solutions in decay processes.

Open inflation models with polynomial potentials can match observational data.

Reconsideration of false vacuum decay mechanisms broadens model possibilities.

Abstract

It appears difficult to construct a simple model for an open universe based on the one bubble inflationary scenario. The reason is that one needs a large mass to avoid the tunneling via the Hawking Moss solution and a small mass for successful slow-rolling. However, Rubakov and Sibiryakov suggest that the Hawking Moss solution is not a solution for the false vacuum decay process because it does not satisfy the boundary condition. Hence, we have reconsidered the arguments for the defect of the simple polynomial model. We point out the possibility that one of the valley bounce belonging to a valley line in the functional space represents the decay process instead of the Hawking Moss solution. Under this presumption, we show an open inflation model can be constructed within the polynomial form of the potential so that the fluctuations can be reconciled with the observations.