f(T) models with phantom divide line crossing

Abstract

In this paper, we propose two new models in f (T ) gravity to realize the crossing of the phantom divide line for the effective equation of state, and we then study the observational constraints on the model parameters. The best fit results suggest that the observations favor a crossing of the phantom divide line.

Generalizations of teleparallel gravity and local Lorentz symmetry

“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] which followed the spirit of f (R) gravity (see Ref. [21] for a review) as a generalization of general relativity.…”

“…Recall that Γ λ µν is an independent connection which satisfies Eq. (9). This implies that the part of this connection which is independent of the metric is just the contorsion tensor K ρ µν .…”

Accelerating f(T) Gravity Models Constrained by Recent Cosmological Data

“…It is particularly interesting to look at models which are able to give rise to an effective eos (defined later) crossing the phantom divide, i.e., w ef f (z) > −1 for z > z ph with z ph the phantom divide redshift. Two recently proposed model of this kind can be obtained setting [12] …”

“…with the sound horizon to distance z given by (12) and z d is the drag redshift. The d z value at z = 0.106 and its error is taken from [21], while [22] gives d z for z = 0.20 and z = 0.35 with the corresponding covariance matrix.…”

Analytic rotating black-hole solutions in N-dimensional f(T) gravity

“…Therefore, guided by the construction of f (R) gravitational theory we are allowed to postulate the Lagrangian of the amended Einstein-Hilbert action as a function of the torsion scalar to extend TEGR in a natural way. This extension is called f (T ), where T is the teleparallelism scalar torsion, gravitational theory [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. It is necessary to note that in f (T ) theory the field equations are of second order while the field equations of f (R) are of fourth order.…”