Quasinormal modes of Schwarzschild black holes in projective invariant Chern-Simons modified gravity

Understand

We generalize the Chern-Simons modified gravity to the metric-affine case and impose projective invariance by supplementing the Pontryagin density with homothetic curvature terms which do not spoil topologicity.

• The latter is then broken by promoting the coupling of the Chern-Simons term to a (pseudo)-scalar field.
• The solutions for torsion and nonmetricity are derived perturbatively, showing that they can be iteratively obtained from the background fields.
• This allows us to describe the dynamics for the metric and the scalar field perturbations in a self-consistent way, and we apply the formalism to the study of quasinormal modes in a Schwarzschild black hole background.