Equation of State of the Transplanckian Dark Energy and the Coincidence Problem

TL;DR

This paper develops a string theory-inspired model of dark energy based on transplanckian modes, deriving a time-dependent equation of state that addresses the cosmic coincidence problem without fine-tuning.

Contribution

It introduces a modified Einstein equation framework for transplanckian physics and derives a dynamic equation of state for dark energy.

Findings

Derived a time-dependent equation of state for transplanckian dark energy.

Provided a mechanism explaining the cosmic coincidence problem.

Modified Einstein equations to incorporate short-distance physics effects.

Abstract

Observational evidence suggests that our universe is presently dominated by a dark energy component and undergoing accelerated expansion. We recently introduced a model, motivated by string theory for short-distance physics, for explaining dark energy without appealing to any fine-tuning. The idea of the transplanckian dark energy (TDE) was based on the freeze-out mechanism of the ultralow frequency modes, $\omega(k)$ of very short distances, by the expansion of the background universe, $\omega(k) \leq H$. In this paper we address the issue of the stress-energy tensor for the nonlinear short-distance physics and explain the need to modify Einstein equations in this regime. From the modified Einstein equations we then derive the equation of state for the TDE model, which has the distinctive feature of being continually time-dependent. The explanation of the coincidence puzzle relies entirely on the intrinsic time-evolution of the TDE equation of state.