Noether currents for the Teukolsky Master Equation

Understand

Conserved currents associated with the time translation and axial symmetries of the Kerr spacetime and with scaling symmetry are constructed for the Teukolsky Master Equation (TME).

• Three partly different approaches are taken, of which the third one applies only to the spacetime symmetries.
• The results yielded by the three approaches, which correspond to three variants of Noether's theorem, are essentially the same, nevertheless.
• The construction includes the embedding of the TME into a larger system of equations, which admits a Lagrangian and turns out to consist of two TMEs with opposite spin weight.