### Abstract

We explore the constraints boundary causality places on the allowable Gauss-Bonnet gravitational couplings in asymptotically AdS spaces, specifically considering spherical black hole solutions. We additionally consider the hyperbolicity properties of these solutions, positing that hyperbolicity-violating solutions are sick solutions whose causality properties provide no information about the theory they reside in. For both signs of the Gauss-Bonnet coupling, spherical black holes violate boundary causality at smaller absolute values of the coupling than planar black holes do. For negative coupling, as we tune the Gauss-Bonnet coupling away from zero, both spherical and planar black holes violate hyperbolicity before they violate boundary causality. For positive coupling, the only hyperbolicity-respecting spherical black holes which violate boundary causality do not do so appreciably far from the planar bound. Consequently, eliminating hyperbolicity-violating solutions means the bound on Gauss-Bonnet couplings from the boundary causality of spherical black holes is no tighter than that from planar black holes.

Original language | English (US) |
---|---|

Article number | 135003 |

Journal | Classical and Quantum Gravity |

Volume | 34 |

Issue number | 13 |

DOIs | |

State | Published - Jun 5 2017 |

Externally published | Yes |

### Fingerprint

### Keywords

- causality
- Gauss-Bonnet gravity
- higher curvature gravity
- hyperbolicity

### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)

### Cite this

*Classical and Quantum Gravity*,

*34*(13), [135003]. https://doi.org/10.1088/1361-6382/aa7101

**Boundary causality versus hyperbolicity for spherical black holes in Gauss-Bonnet gravity.** / Andrade, Tomás; Cáceres, Elena; Keeler, Cynthia.

Research output: Contribution to journal › Article

*Classical and Quantum Gravity*, vol. 34, no. 13, 135003. https://doi.org/10.1088/1361-6382/aa7101

}

TY - JOUR

T1 - Boundary causality versus hyperbolicity for spherical black holes in Gauss-Bonnet gravity

AU - Andrade, Tomás

AU - Cáceres, Elena

AU - Keeler, Cynthia

PY - 2017/6/5

Y1 - 2017/6/5

N2 - We explore the constraints boundary causality places on the allowable Gauss-Bonnet gravitational couplings in asymptotically AdS spaces, specifically considering spherical black hole solutions. We additionally consider the hyperbolicity properties of these solutions, positing that hyperbolicity-violating solutions are sick solutions whose causality properties provide no information about the theory they reside in. For both signs of the Gauss-Bonnet coupling, spherical black holes violate boundary causality at smaller absolute values of the coupling than planar black holes do. For negative coupling, as we tune the Gauss-Bonnet coupling away from zero, both spherical and planar black holes violate hyperbolicity before they violate boundary causality. For positive coupling, the only hyperbolicity-respecting spherical black holes which violate boundary causality do not do so appreciably far from the planar bound. Consequently, eliminating hyperbolicity-violating solutions means the bound on Gauss-Bonnet couplings from the boundary causality of spherical black holes is no tighter than that from planar black holes.

AB - We explore the constraints boundary causality places on the allowable Gauss-Bonnet gravitational couplings in asymptotically AdS spaces, specifically considering spherical black hole solutions. We additionally consider the hyperbolicity properties of these solutions, positing that hyperbolicity-violating solutions are sick solutions whose causality properties provide no information about the theory they reside in. For both signs of the Gauss-Bonnet coupling, spherical black holes violate boundary causality at smaller absolute values of the coupling than planar black holes do. For negative coupling, as we tune the Gauss-Bonnet coupling away from zero, both spherical and planar black holes violate hyperbolicity before they violate boundary causality. For positive coupling, the only hyperbolicity-respecting spherical black holes which violate boundary causality do not do so appreciably far from the planar bound. Consequently, eliminating hyperbolicity-violating solutions means the bound on Gauss-Bonnet couplings from the boundary causality of spherical black holes is no tighter than that from planar black holes.

KW - causality

KW - Gauss-Bonnet gravity

KW - higher curvature gravity

KW - hyperbolicity

UR - http://www.scopus.com/inward/record.url?scp=85021053148&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85021053148&partnerID=8YFLogxK

U2 - 10.1088/1361-6382/aa7101

DO - 10.1088/1361-6382/aa7101

M3 - Article

VL - 34

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 13

M1 - 135003

ER -