On the cosmology of scalar-tensor-vector gravity theory

• Verfasst von: Jamali, Sara [VerfasserIn]
• Verfasst von: Roshan, Mahmood [VerfasserIn]
• Verfasst von: Amendola, Luca [VerfasserIn]
• Titel: On the cosmology of scalar-tensor-vector gravity theory
• Verf.angabe: Sara Jamali, Mahmood Roshan and Luca Amendola
• Fussnoten: Gesehen am 19.10.2017
• Titel Quelle: Enthalten in: De.arxiv.org
• Jahr Quelle: 2017
• Band/Heft Quelle: (2017) Artikel-Nummer 1707.02841, 16 Seiten
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1564571408

Abstract

We consider the cosmological consequences of a special scalar-tensor-vector theory of gravity, known as MOG in the literature, proposed to address the dark matter problem. This theory introduces two scalar fields $G(x)$ and $\mu(x)$, and one vector field $\phi_{\alpha}(x)$, in addition to the metric tensor. We set the corresponding self-interaction potentials to zero, as in the standard form of MOG. Then using the phase space analysis in the flat Friedmann-Robertson-Walker background, we show that the theory possesses a viable sequence of cosmological epochs with acceptable time dependency for the cosmic scale factor. We also investigate MOG's potential as a dark energy model and show that extra fields in MOG can not provide a late time accelerated expansion. Furthermore, using a dynamical system approach to solve the non-linear field equations numerically, we calculate the angular size of the sound horizon, i.e. $\theta_{\text{s}}$, in MOG. We find that $8\times 10^{-3}\text{rad}<\theta_{\text{s}}<8.2\times 10^{-3} \text{rad} $ which is way outside the current observational bounds. Finally we generalize MOG to find a model that passes the sound-horizon constraint and might produce a viable version of MOG.