# Inflation in generalized unimodular gravity

## TL;DR

This paper explores generalized unimodular gravity as a model for cosmological inflation, showing it can produce a realistic primordial power spectrum and discussing its potential for explaining dark energy and quantum transitions.

## Contribution

It demonstrates that generalized unimodular gravity can serve as an inflationary model with observable predictions, extending its application beyond dark energy.

## Key findings

- Scalar gravitons generate a red tilted primordial power spectrum.
- The theory's parameters can be reconstructed from cosmological data.
- Alternative mechanisms for cosmic acceleration are briefly discussed.

## Abstract

The recently suggested generalized unimodular gravity theory, which was originally put forward as a model of dark energy, can serve as a model of cosmological inflation driven by the effective perfect fluid -- the dark purely gravitational sector of the theory. Its excitations are scalar gravitons which can generate, in the domain free from ghost and gradient instabilities, the red tilted primordial power spectrum of CMB perturbations matching with observations. The reconstruction of the parametric dependence of the action of the theory in the early inflationary Universe is qualitatively sketched from the cosmological data. The alternative possibilities of generating the cosmological acceleration or quantum transition to the general relativistic phase of the theory are also briefly discussed.