# On the ghost issue of extended quasidilaton

## TL;DR

This paper investigates the extended quasidilaton theory and confirms the presence of the Boulware-Deser ghost through independent analysis using cosmological perturbations and Stuckelberg methods.

## Contribution

It provides an independent verification of the ghost issue in extended quasidilaton models using multiple analytical approaches.

## Key findings

- Confirmation of the Boulware-Deser ghost presence
- Analysis with broken diffeomorphisms and Stuckelberg approach
- Supports previous claims of ghost instability

## Abstract

We report on our independent investigations of the puzzle of cosmological perturbations in extended quasidilaton. We confirm the claims of presence of the Boulware-Deser ghost. We use both the language of cosmological perturbations with broken diffeomorphisms and the Stuckelberg approach.