Black holes with scalar charge.
Abstract
It is shown that scalar charge is an admissible parameter characterizing a stationary black hole with an exterior devoid of matter. A previous solution by Bekenstein (1974) of Einstein's equations with stressenergy of electromagnetic and conformal scalar field is presented which has a blackhole geometry, is parametrized by electric and scalar charges, and whose scalar field is unbounded at the event horizon. The infinity of the scalar field is shown not to be physically pathological, not to be associated with an infinite potential barrier for test scalar charges, not to cause the termination of any trajectories of these test particles at finite proper time, and not to be connected with unbounded tidal accelerations between neighboring trajectories. It is concluded that the present solution represents a twoparameter family of bare stationary black holes and that the conjecture that 'black holes have no hair' must be reinterpreted to allow for scalar charge as a black hole parameter.
 Publication:

Annals of Physics
 Pub Date:
 May 1975
 DOI:
 10.1016/00034916(75)902791
 Bibcode:
 1975AnPhy..91...75B
 Keywords:

 Black Holes (Astronomy);
 Einstein Equations;
 Electric Charge;
 Electromagnetic Fields;
 Field Theory (Physics);
 Particle Trajectories;
 Angular Momentum;
 Maxwell Equation;
 Particle Mass;
 Scalars;
 Astrophysics