Revisiting metric perturbations in tensor-vector-scalar theory

Abstract

I revisit cosmological perturbations in Bekenstein's tensor-vector-scalar theory (TeVeS). Considering only scalar modes in the conformal Newtonian gauge, the extra degrees of freedom are expressed in a way suitable for studying modifications at the level of the metric potentials. Assuming a universe in the matter-dominated phase, I discuss the mechanism responsible for boosting structure growth, and confirm the vector field as its key ingredient. Using a semi-analytic approach, I further characterize the evolution of density perturbations and the potentials on sub- and superhorizon scales.

12 pages, 6 figures; updated Figs. 3, 5, and 6, improved discussion of potential and density growth, accepted version