A String-Inspired Quintom Model Of Dark Energy

TL;DR

This paper introduces a novel quintom dark energy model inspired by string theory, featuring a single scalar field with a complex Lagrangian that allows the equation of state to cross the cosmological constant boundary, expanding dark energy modeling.

Contribution

It presents a new string-inspired scalar field model for dark energy that enables the equation of state to cross the cosmological constant boundary, unifying tachyon and quintom features.

Findings

Model reduces to tachyon Lagrangian when eta' 0.

Equation of state crosses the cosmological constant boundary.

Cosmological evolution of the model is explicitly studied.

Abstract

We propose in this paper a quintom model of dark energy with a single scalar field $\phi$ given by the lagrangian ${\cal L}=-V(\phi)\sqrt{1-\alpha^\prime\nabla_{\mu}\phi\nabla^{\mu}\phi +\beta^\prime \phi\Box\phi}$. In the limit of $\beta^\prime\to$0 our model reduces to the effective low energy lagrangian of tachyon considered in the literature. We study the cosmological evolution of this model, and show explicitly the behaviors of the equation of state crossing the cosmological constant boundary.