Does cosmological structure formation require dark energy?

Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UK

Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Precision measurements of anisotropies in the cosmic microwave background and of the clustering of large-scale structure have supposedly established that the universe is presently dominated by “dark energy” which has negative pressure and behaves similarly to a cosmological constant. This is based on the assumption that the primordial density perturbation has a nearly scale-invariant power-law spectrum and that the dark matter consists of “cold” particles. However there are theoretical and observational indications that the spectrum is not scale-free and it is known that sub-eV mass neutrinos contribute a small component of hot dark matter. This would be sufficient to fit the same observational data without requiring any dark energy.