Induced Affine Inflation

TL;DR

This paper explores induced affine gravity, where gravity and the metric emerge without Einstein-Jordan ambiguity, and finds it predicts a relatively large tensor-to-scalar ratio in inflationary models.

Contribution

It introduces a framework for induced gravity in affine geometry that avoids the traditional Einstein-Jordan ambiguity and demonstrates its implications for inflationary predictions.

Findings

Induced affine gravity generates the metric without ambiguity.

The model predicts a large tensor-to-scalar ratio.

Affine gravity provides a consistent, ambiguity-free inflationary framework.

Abstract

Induced gravity, metrical gravity in which gravitational constant arises from vacuum expectation value of a heavy scalar, is known to suffer from Jordan frame vs. Einstein frame ambiguity, especially in inflationary dynamics. Induced gravity in affine geometry, as we show here, leads to an emergent metric and gravity scale, with no Einstein-Jordan ambiguity. While gravity is induced by the vacuum expectation value of the scalar field, nonzero vacuum energy facilitates generation of the metric. Our analysis shows that induced gravity results in a relatively large tensor-to-scalar ratio in both metrical and affine gravity setups. However, the fact remains that the induced affine gravity provides an ambiguity-free framework.