A Model of Inflation

TL;DR

This paper proposes a quantum gravitational model of cosmic inflation where the universe's rapid expansion results from a phase transition in spacetime's microscopic structure, eliminating the need for specific matter fields.

Contribution

It introduces a novel inflation model driven by spacetime's quantum structure and phase transition, differing from traditional matter-field driven inflation models.

Findings

Spacetime undergoes a phase transition reducing the cosmological constant from $10^{87}s^{-2}$ to $10^{-35}s^{-2}$.

The model reproduces conventional inflationary predictions during the phase transition.

Inflation ends abruptly after the phase transition, aligning with observed universe expansion.

Abstract

We consider a novel model of cosmic inflation. In our model one does not need any specific matter field to drive inflation, but inflation stems from the microscopic, Planck scale structure of spacetime, thus being of quantum gravitational origin. At a certain temperature spacetime performs a phase transition, where the cosmological constant drops from a huge, Planck scale value, which is about $10^{87}s^{-2}$ to its present, pretty small value $10^{-35}s^{-2}$. When the cosmological constant is large, the universe goes through a period of very rapid expansion which, however, comes to an abrupt end after the phase transition has been completed. Assuming that the cosmological constant depends on the age of the universe in an appropriate manner during the phase transition one may recover the predictions of the conventional inflationary scenario.