Key points are not available for this paper at this time.
The Klein-Gordon equation for a scalar field of mass is analyzed in the geometry of a rotating black hole. It is shown that in the limit 1, i. e. , particle Compton wavelength much larger than the size of the black hole, the scalar field is unstable with an e-folding time of = (a{M) }^-124 () ^-8^-1.
Steven Detweiler (Sat,) studied this question.