Scale-invariant power spectra from a Weyl-invariant scalar-tensor theory

TL;DR

This paper demonstrates that Weyl-invariance in a scalar-tensor theory naturally leads to scale-invariant scalar and tensor power spectra in de Sitter spacetime, highlighting a fundamental symmetry's role in cosmological fluctuations.

Contribution

It establishes a direct link between Weyl-invariance of the action and the scale-invariance of power spectra in de Sitter spacetime, providing a novel theoretical insight.

Findings

Weyl-invariance guarantees scale-invariance of power spectra.

Scalar and tensor spectra are scale-invariant in the model.

Deep connection between Weyl-invariance and cosmological scale-invariance.

Abstract

We obtain scale-invariant scalar and tensor power spectra from a Weyl-invariant scalar-tensor theory in de Sitter spacetime. This implies that the Weyl-invariance guarantees to implement the scale-invariance of power spectrum in de Sitter spacetime. We establish a deep connection between the Weyl-invariance of the action and scale-invariance of power spectrum in de Sitter spacetime.