Can Inflation solve the Hierarchy Problem?

TL;DR

The work proposes a dynamical solution to the hierarchy problem by embedding inflation in a false-vacuum scenario with a scalar field non-minimally coupled to gravity. Inflation slows and ends via bubble nucleation, while the evolution of the coupling function $f(\phi)$ dynamically lifts the Planck mass from a TeV-scale $M$ to $M_{Pl}$, with the final hierarchy tied to the tunneling rate $\Gamma_{\rm vac}$. The model makes sharp, testable predictions, including a TeV-scale reheating temperature, a potentially large tensor-to-scalar ratio in some realizations, and a gravitational-wave signal peaking around $0.1$ mHz detectable by LISA. Depending on parameter choices, the framework remains consistent with WMAP3 and offers observable connections between LHC-scale physics and cosmological observables.

Abstract

Inflation with tunneling from a false to a true vacuum becomes viable in the presence of a scalar field that slows down the initial de Sitter phase. As a by-product this field also sets dynamically the value of the Newton constant observed today. This can be very large if the tunneling rate (which is exponentially sensitive to the barrier) is small enough. Therefore along with Inflation we also provide a natural dynamical explanation for why gravity is so weak today. Moreover we predict a spectrum of gravity waves peaked at around 0.1 mHz, that will be detectable by the planned space inteferometer LISA. Finally we discuss interesting predictions on cosmological scalar and tensor fluctuations in the light the WMAP 3-year data.