Redundant and Physical Black Hole Parameters: Is there an independent physical dilaton charge?

Understand

Black holes as solutions to gravity theories, are generically identified by a set of parameters.

• Some of these parameters are associated with black hole physical conserved charges, like ADM charges.
• There can also be some "redundant parameters." We propose necessary conditions for a parameter to be physical.
• The conditions are essentially integrability and non-triviality of the charge variations arising from "parametric variations," variation of the solution with respect to the chosen parameters.