Classification of shift-symmetric Horndeski theories and hairy black holes

Saravani, Mehdi; Sotiriou, Thomas P.

Abstract

No-hair theorems for scalar-tensor theories imply that the trivial scalar field configuration is the unique configuration around stationary black hole spacetimes. The most basic assumption in these theorems is that a constant scalar configuration is actually admissible. In this paper, we classify shift-symmetric Horndeski theories according to whether or not they admit the trivial scalar configuration as a solution and under which conditions. Local Lorentz symmetry and the presence of a linear coupling between the scalar field and Gauss-Bonnet invariant plays feature prominently in this classification. We then use the classification to show that any theory without linear Gauss-Bonnet coupling that respects Local Lorentz symmetry admits all GR solutions. We also study the scalar hair configuration around black hole spacetimes in theories where the linear Gauss-Bonnet coupling is present. We show that the scalar hair of the configuration is secondary, fixed by the regularity of the horizon, and is determined by the black hole horizon properties.

Citation

Saravani, M., & Sotiriou, T. P. (2019). Classification of shift-symmetric Horndeski theories and hairy black holes. Physical Review D, 99(12), Article 124004. https://doi.org/10.1103/physrevd.99.124004

• Journal Article Type: Article
• Acceptance Date: May 12, 2019
• Online Publication Date: Jun 6, 2019
• Publication Date: Jun 15, 2019
• Deposit Date: Jun 17, 2019
• Publicly Available Date: Jul 5, 2019
• Journal: Physical Review D
• Print ISSN: 2470-0010
• Electronic ISSN: 2470-0029
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 99
• Issue: 12
• Article Number: 124004
• DOI: https://doi.org/10.1103/physrevd.99.124004
• Keywords: Physics and Astronomy (miscellaneous)
• Public URL: https://nottingham-repository.worktribe.com/output/2199528
• Publisher URL: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.99.124004
• Contract Date: Jul 5, 2019