Teleparallel Dark Energy with Purely Non-minimal Coupling to Gravity

TL;DR

This paper introduces a simple teleparallel dark energy model with non-minimal gravity coupling, demonstrating late-time acceleration, tracker behavior, phantom crossing, and finite-time singularities, supported by analytic solutions and observational constraints.

Contribution

It presents the first purely non-minimal teleparallel dark energy model without self-potential, analyzing its cosmic evolution and observational viability.

Findings

The model predicts late-time cosmic acceleration.

Analytic solutions are derived for different cosmic eras.

Observational data constrains the model parameters.

Abstract

We propose the simplest model of teleparallel dark energy with purely a non-minimal coupling to gravity but no self-potential, a single model possessing various interesting features: simplicity, self-potential-free, the guaranteed late-time cosmic acceleration driven by the non-minimal coupling to gravity, tracker behavior of the dark energy equation of state at earlier times, a crossing of the phantom divide at a late time, and the existence of a finite-time future singularity. We find the analytic solutions of the dark-energy scalar field respectively in the radiation, matter, and dark energy dominated eras, thereby revealing the above features. We further illustrate possible cosmic evolution patterns and present the observational constraint of this model obtained by numerical analysis and data fitting.