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

Abstract: We generalize the Chern-Simons theory of gravity to the metric-affine case, where projective invariance is recovered by enlarging the Pontryagin density with homothetic curvature terms which do not spoil topologicity. This one is then broken by promoting the coupling to the Chern-Simons term to a dynamical scalar field, and we derive at the perturbative level the solutions for torsion and nonmetricity, showing that they can be iteratively obtained from the background metric and the derivative of the scalar field. That 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 for a Schwarzschild black hole. By adopting numerical techniques, we show that in the absence of the kinetic term for the scalar field the latter is still endowed with a proper dynamical character, contrary to non dynamical Chern-Simons theory in metric formalism. Finally, we compute the quasinormal frequencies and characterize the late-time power law tails, comparing the results with the outcomes of the purely metric approach.

astrophysicscondensed mattergeneral relativity and quantum cosmologyhigh energy physicsmathematical physicsclassical physicsgeneral physics

Audience: researchers in the topic

Theoretical physics seminar @ Tartu