Spectrum of Cosmic Microwave Fluctuations and the Formation of Galaxies in a Modified Gravity Theory

TL;DR

This paper explores a modified gravity theory featuring a Bose-Einstein condensate of a vector particle, explaining cosmic microwave background fluctuations and galaxy formation without dark matter.

Contribution

It introduces a modified gravity model with a Bose-Einstein condensate that accounts for CMB data and galaxy formation, providing an alternative to dark matter.

Findings

The model fits CMB acoustic oscillation data.

The condensate forms primordial structures for galaxies.

Galaxy rotation curves are well explained by the modified law.

Abstract

A modified gravity (MOG) possesses a light, neutral vector particle called a ``phion'' associated with a vector field $\phi^\mu$, which forms a cold fluid of Bose-Einstein condensates before recombination with zero pressure and zero shear viscosity. The energy density associated with this Bose-Einstein condensate fluid dominates the energy density before recombination and produces a density parameter, $\Omega_\phi\sim 0.3$, that together with the fractional baryon density $\Omega_b\sim 0.04$, and a cosmological constant parameter $\Omega_\Lambda\sim 0.7$ yields an approximate fit to the data for the acoustical oscillations in the CMB power spectrum. The quantum phion condensate fluid is abundant well before recombination and can clump and form the primordial structure for galaxies. At late times in the expanding universe, in local bound systems such as galaxies ordinary baryonic matter dominates the matter density. For galactic systems in the present epoch, the modified Newtonian acceleration law determined by MOG describes well galaxy rotation curve data and X-ray cluster mass profile data.