Photon sphere and quasinormal modes in AdS/CFT

Understand

Photon spheres are the characteristic of general black holes, thus are a suitable touchstone for the emergence of gravitational spacetime in the AdS/CFT correspondence.

• We provide a spectral analysis of an AdS Schwarzschild black hole near its photon sphere.
• We find that quasinormal modes near the photon sphere reflect the AdS boundary, resulting in a peculiar spectral pattern.
• Our large angular momentum analysis owes to an analogue to solvable Schr\"odinger equations such as an inverted harmonic oscillator and the P\"oschl-Teller model, with a Dirichlet boundary condition.