Cosmic Expansion via Axion-Induced Quintessence

Abstract: In this paper, dark energy is modelled via a spherically symmetric quintessence scalar field $\varphi$, the dynamics of which are found to be analogous to a pendulum. This is due to a driving axion potential $V(\left|\varphi\right|)$, whose origins reside within the study of quantum chromodynamics (QCD). The effect of a cosmological constant $\Lambda$, introduced to represent the vacuum energy of space, is also investigated. Preliminary results suggest that $\Lambda$ is analogous to a spring-constant, and thus determining the elasticity of space. Additionally, a cosmological scale-factor $a(t,r)$, notably with an added spatial dependence, is also considered. We propose that due to this inhomogeneous scale-factor, the energy-density is characteristic of temperature fluctuations observed within the cosmic microwave background. Such fluctuations could ultimately lead to a universe composed of filaments and voids; vast expanses of space, separated by regions of localised matter/energy-density. Finally, we provide a means of screening both the cosmological constant and curvature of the universe, to effective values that are more consistent with experimental observation.