Scrambling in Charged Hairy Black Holes and the Kasner Interior

We analyze how the axion parameter, the Einstein-Maxwell-Scalar coupling constant, and charge density from Maxwell field affect the chaotic feature of a charged hairy black hole, as characterized by the quantum Lyapunov exponent. Due to relevant deformation in the boundary theory coming from a scalar bulk field, the bulk solution flows into more general Kasner spacetime in the interior of the black hole, near the singularity. We inject charged shock waves from the asymptotic boundary and calculate the out-of-time-ordered correlators holographically, which can probe chaos. The ratio of the quantum Lyapunov exponent with respect to the surface gravity is reduced as the deformation parameter increased, while the Lyapunov exponent of the deformed geometry can be greater than the axion Reissner-Nordström case when the deformation parameter is large enough. We also study how this deformation, along with the added parameters, affect other chaotic properties such as the butterfly velocity and the scrambling time delay. Furthermore, we also analyze the region where Kasner spacetime undergoes Kasner inversion/transition deeper inside the black hole.