Galaxy N-z Relation and CMB Spectrum Based on Cosmological Model with Scalar Field Having Modified Potential Form

TL;DR

This paper presents a cosmological model with a non-minimally coupled scalar field and a modified potential that explains galaxy distribution patterns and CMB anisotropies, matching observations from 2dF and WMAP.

Contribution

The authors introduce a new scalar field potential form that enables the scalar field to evolve appropriately, reproducing galaxy distribution and CMB features simultaneously.

Findings

Successfully models galaxy N-z relation and CMB spectrum

Scalar field remains small during nucleosynthesis, then grows at z~1

Modified potential controls scalar field growth epoch

Abstract

We have succeeded in establishing a cosmological model with a non-minimally coupled scalar field $\phi$ that can account not only for the spatial periodicity or the picket-fence structure exhibited by the galaxy $N$-$z$ relation of the 2dF survey, but also for the spatial power spectrum of the cosmic microwave background radiation (CMB) temperature anisotropy observed by the WMAP satellite. The scalar field of our model universe starts from an extremely small value at around the nucleosynthesis epoch, remains in that state for sufficiently long periods, allowing sufficient time for the CMB temperature anisotropy to form, and then starts to grow in magnitude at the redshift $z$ of $\sim 1$, followed by a damping oscillation which is required to reproduce the observed picket-fence structure of the $N$-$z$ relation. To realize such behavior of the scalar field, we have found it necessary to introduce a new form of potential $V(\phi)\propto \phi^2\exp(-q\phi^2)$, with $q$ being a constant. Through this parameter $q$, we can control the epoch at which the scalar field starts growing.