A Note on the Stability of the Dark Energy Model from Time Crystals

In this note, we investigate the stability of the dark energy model from time crystals proposed in [1]. We emphasize two ingredients, the coupling of the scalar field to gravity, and the fact that these time crystals are on an expanding FRW background, which play a crucial role in the field's dynamics. The Hubble parameter, which contributes a drag term to the equations of motion, grows with time until the scale factor diverges. When taken into account, these factors also alleviate the stability concern of [2].