Massive vector fields in Kerr-Newman and Kerr-Sen black hole spacetimes
Massive vector fields in Kerr-Newman and Kerr-Sen black hole spacetimes
The superradiant instability modes of ultralight massive vector bosons are studied for weakly charged rotating black holes in Einstein--Maxwell gravity (the Kerr--Newman solution) and low-energy heterotic string theory (the Kerr--Sen black hole). We show that in both these cases, the corresponding massive vector (Proca) equations can be fully separated, exploiting …