Non-linear terms in 2D cosmology

Abstract

In this work we investigate the behavior of two-dimensional (2D) cosmological models, starting with the Jackiw-Teitelboim (JT) theory of gravitation. A geometrical term, non-linear in the scalar curvature $R$, is added to the JT dynamics to test if it could play the role of dark energy in a 2D expanding universe. This formulation makes possible, first, the description of an early (inflationary) 2D universe, when the van der Waals (vdW) equation of state is used to construct the energy-momentum tensor of the gravitational sources. Second, it is found that for later times the non-linear term in $R$ can generate an old 2D universe in accelerated expansion, where an ordinary matter dominated era evolves into a decelerated/accelerated transition, giving to the dark energy effects a geometrical origin. The results emerge through numerical analysis, following the evolution in time of the scale factor, its acceleration, and the energy densities of constituents.

tex file plus figures in two zipped files. To appear in Europhys. Lett

References in corpus (2)

• Applications to cosmological models of a complex scalar field coupled to a U(1) vector gauge field
• Transition from accelerated to decelerated regimes in JT and CGHS cosmologies

Cited by in corpus (1)

• 3D gravity and non-linear cosmology