Comment on "Some exact quasinormal frequencies of a massless scalar field in Schwarzschild spacetime"

Understand

A new branch of quasinormal modes for a massless scalar field propagating on the Schwarzschild spacetime was recently announced [1807.04513].

• We review the quasinormal modes characterisation and arguments and identify the flaws in their proof.
• Then, we preset explicit counterexamples to such arguments.
• Finally, we study the modes via alternative methods and do not find the new branch.