Charged black holes in a generalized scalartensor gravity model
Abstract
We study 4dimensional charged and static black holes in a generalized scalartensor gravity model, in which a shift symmetry for the scalar field exists. For vanishing scalar field the solution corresponds to the ReissnerNordström (RN) solution, while solutions of the full scalargravity model have to be constructed numerically. We demonstrate that these black holes support Galilean scalar hair up to a maximal value of the scalartensor coupling that depends on the value of the charge and can be up to roughly twice as large as that for uncharged solutions. The Hawking temperature T_{H} of the hairy black holes at maximal scalartensor coupling decreases continuously with the increase of the charge and reaches T_{H} = 0 for the highest possible charge that these solutions can carry. However, in this limit, the scalartensor coupling needs to vanish. The limiting solution hence corresponds to the extremal RN solution, which does not support regular Galilean scalar hair due to its AdS_{2} ×S^{2} nearhorizon geometry.
 Publication:

Physics Letters B
 Pub Date:
 September 2017
 DOI:
 10.1016/j.physletb.2017.06.069
 arXiv:
 arXiv:1704.04655
 Bibcode:
 2017PhLB..772..476B
 Keywords:

 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 11 pages including 5 figures