Back-reaction effect in power-law inflation

TL;DR

This paper investigates back-reaction effects in power-law inflation, revealing that scalar field fluctuation spectra are scale-invariant across cosmological scales regardless of the expansion rate, but their amplitude depends on it.

Contribution

It demonstrates that back-reaction effects lead to a scale-invariant fluctuation spectrum independent of the expansion rate in power-law inflation models.

Findings

Scalar fluctuation spectrum is scale-invariant for cosmological scales.

Spectrum does not depend on the power-law index p.

Fluctuation amplitude depends on the expansion rate p.

Abstract

I consider a power-law inflationary model taking into account back-reaction effects. The interesting result is that the spectrum for the scalar field fluctuations does not depends on the expansion rate of the universe $p$ and that it result to be scale invariant for cosmological scales. However, the amplitude for these fluctuations depends on $p$.