Phantom dark energy with tachyonic instability: metric perturbations

TL;DR

This paper investigates how metric perturbations evolve in a phantom dark energy model with tachyonic instability, showing they grow exponentially and could impact late-time cosmological observations.

Contribution

It introduces an analysis of metric perturbations in a novel phantom dark energy model with tachyonic instability, highlighting their exponential growth over time.

Findings

Metric perturbations grow exponentially at late times.

Initial perturbations are set by vacuum fluctuations.

Potential implications for cosmological phenomenology.

Abstract

We study the behavior of metric perturbations in a recently proposed model of phantom dark energy with tachyonic instability at long wavelengths. We find that metric perturbations exponentially grow in time, starting from very small values determined by vacuum fluctuations, and may become sizeable at late times. This property may be of interest for phenomenology.