Quantum cosmological perturbations in bouncing models with mimetic dark matter

TL;DR

This paper demonstrates that mimetic bouncing cosmological models can produce scale-invariant or red-tilted power spectra consistent with observations without requiring quantum effects, by analyzing quantum vacuum fluctuations.

Contribution

It shows that mimetic cosmology can generate realistic cosmological perturbations in bouncing models, with adjustable spectral indices and amplitudes, without quantum background effects.

Findings

All models produce scale-invariant spectra compatible with observations.

Adjusting the scalar potential yields a red-tilted spectral index.

Bounce scales within 10^5 to 10^9 Planck lengths are viable.

Abstract

We calculate the power spectrum of cosmological perturbations originated from quantum vacuum fluctuations in bouncing scenarios proposed in Ref.~\cite{chamseddine2014cosmology} in the framework of mimetic cosmology. We show that all physically relevant models produce scale invariant spectral indices, and amplitudes compatible with observations provided that the bounce occurs at length scales $t_0$ inside the physically reasonable interval $10^5 l_p < t_0 < 10^9 l_p$. We also show that by slightly modifying the scalar field potential proposed in Ref.~\cite{chamseddine2014cosmology}, we can also obtain the observed red-tilted spectral index, with the same amplitude constraints. Hence, mimetic cosmology provides reasonable bouncing cosmological models without the need of any background quantum effect.