Cosmological applications of $F(T,T_G)$ gravity

TL;DR

This paper explores a new modified gravity theory based on torsion and Gauss-Bonnet terms, offering a unified cosmological model from inflation to late-time acceleration without a cosmological constant.

Contribution

It introduces and analyzes the cosmological implications of the novel $F(T,T_G)$ gravity, distinct from existing torsion and curvature-based theories.

Findings

Provides a unified description of cosmic history from inflation to acceleration.

Dark energy equation-of-state can be quintessence, phantom, or crossing the phantom divide.

Models can explain late-time acceleration without a cosmological constant.

Abstract

We investigate the cosmological applications of $F(T,T_G)$ gravity, which is a novel modified gravitational theory based on the torsion invariant $T$ and the teleparallel equivalent of the Gauss-Bonnet term $T_{G}$. $F(T,T_{G})$ gravity differs from both $F(T)$ theories as well as from $F(R,G)$ class of curvature modified gravity, and thus its corresponding cosmology proves to be very interesting. In particular, it provides a unified description of the cosmological history from early-times inflation to late-times self-acceleration, without the inclusion of a cosmological constant. Moreover, the dark energy equation-of-state parameter can be quintessence or phantom-like, or experience the phantom-divide crossing, depending on the parameters of the model.