Axion induced angular momentum reversal in Kerr-like black holes

Chatzifotis, Nikos; Dorlis, Panagiotis; Mavromatos, Nick E.; Papantonopoulos, Eleftherios

doi:10.1103/physrevd.106.084002

Cited by 11 publications

(3 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected, the majority of analytical solutions for compact objects in Horndeski theories have been obtained within the subclass of theories that enjoy parity symmetry ϕ → −ϕ and/or shift symmetry ϕ → ϕ + cst [54,[67][68][69][70][71][72][73][74]. However, under physical grounds there are no compelling reasons to restrict ourselves to theories with such symmetries, and in consequence, this freedom opens the possibility to explore spacetime geometries with quite different properties than GR [75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. In this scenario, there is a potential risk of dealing with much more involved field equations, precluding the existence of analytical solutions.…”

Section: Introductionmentioning

confidence: 97%

Stealth Ellis wormholes in Horndeski theories

Bakopoulos,

Chatzifotis,

Erices

et al. 2023

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

In this work we are revisiting the well studied Ellis wormhole solution in a Horndeski theory motivated from the Kaluza-Klein compactification procedure of the more fundamental higher dimensional Lovelock gravity. We show that the Ellis wormhole is analytically supported by a gravitational theory with a non-trivial coupling to the Gauss-Bonnet term and we expand upon this notion by introducing higher derivative contributions of the scalar field. The extension of the gravitational theory does not yield any back-reacting component on the spacetime metric, which establishes the Ellis wormhole as a stealth solution in the generalized framework. We propose two simple mechanisms that dress the wormhole with an effective ADM mass. The first procedure is related to a conformal transformation of the metric which maps the theory to another Horndeski subclass, while the second one is inspired by the spontaneous scalarization effect on black holes.

show abstract

Section: Introductionmentioning

confidence: 97%

Stealth Ellis wormholes in Horndeski theories

Bakopoulos,

Chatzifotis,

Erices

et al. 2023

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The violations are generated by the amended term of the Carroll-Field-Jackiw expression i.e., f µ F µν A ν with f µ ≡ ∂ µ ϕ being the axial vector that is responsible for Lorentz and/or Parity symmetry breaking and A ν is the gauge potential of the electromagnetic field. In general, f µ links to one of the coefficients of the Lorentz and/or Parity violation in the standard model extension [27][28][29][30][31][32][33]. In the same manner, the Chern-Simons amendment of the Maxwell electrodynamics adds to the action of general relativity with a non-minimal coupling between ϕ(x) and the gravitational Pontryagin density which is figured as ϕR R where R R ≡ R abcd Rabcd .…”

Section: Introductionmentioning

confidence: 99%

Slow-rotating black holes with potential in dynamical Chern-Simons modified gravitational theory

Nashed

Nojiri

2023

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

The Chern-Simons amended gravity theory appears as a low-energy effective theory of string theory. The effective theory includes an anomaly-cancelation correction to the Einstein-Hilbert action. The Chern-Simons expression consists of the product φRR̃ of the Pontryagin density RR̃ with a scalar field φ, where the latter is considered a background field (dynamical construction or non-dynamical construction). Many different solutions to Einstein's general relativity continue to be valid in the amended theories. The Kerr metric is, however, considered an exceptional case that raised a search for rotating black hole solutions. We generalize the solution presented in Phys. Rev. D 77 (2008) 064007 by allowing the potential V to have a non-vanishing value, and we discuss three different cases of the potential, that is, V = const., V ∝ φ, and V ∝ φ 2 cases. This study presents, for the first time, novel solutions prescribing rotating black holes in the frame of the dynamical formulation of the Chern-Simons gravity, where we include a potential and generalize the previously derived solutions. We derive solutions in the slow-rotation limit, where we write the parameter of the slow-rotation expansion by ε. These solutions are axisymmetric and stationary, and they make a distortion of the Kerr solution by a dipole scalar field. Furthermore, we investigate that the correction to the metric behaves in the inverse of the fourth order of radial distance from the center of the black hole as V ∝ φ. This suggests that any meaningful limits from the weak-field experiments could be passed. We show that the energy conditions associated with the scalar field of the case V ∝ φ are non-trivial and have non-trivial values to the leading order. These non-trivial values come mainly from the contribution of the potential. Finally, we derived the stability condition using the geodesic deviations. We conclude this study by showing that other choices of the potential, i.e., V ∝ φn , where n > 2 are not allowed because all the solutions to these cases will be of order 𝒪(ε 2), which is not covered in this study.

show abstract

“…In [41], black hole solutions with well defined AdS asymptotics were extracted in CS gravities, while in d-dimensional solutions, the stability of CS black holes under scalar perturbations were investigated in [42]. CS gravity slowly rotating Kerr-like black hole solutions have been found and studied in [43,44].…”

Section: Introductionmentioning

confidence: 99%

On Thermal Stability of Hairy Black Holes

Chatzifotis¹,

Dorlis²,

Mavromatos³

et al. 2023

Preprint

View full text Add to dashboard Cite

We discuss thermodynamical stability for hairy black hole spacetimes, viewed as defects in the thermodynamical parameter space, taking into account the backreaction of a secondary hair onto the spacetime geometry, which is modified non trivially. We derive, in a model independent way, the conditions for the hairy black hole with the secondary hair to reach a stable thermal equilibrium with the heat bath. Specifically, if the scalar hair, induced by interactions of the matter fields with quadratic-curvature corrections, produces an inner horizon in the deformed geometry, a thermodynamically stable configuration will be reached with the black hole becoming extremal in its final stage. We also attempt to make some conjectures concerning the implications of this thermal stability for the existence of a minimum length in a quantum space time. Contents I. Introduction 1 II. Black Holes in a Thermal Bath and Stability Arguments 3 III. Black Holes as Thermodynamical Topological Defects 6 IV. Back Reaction of Secondary Hair and Black Hole Thermodynamical Stability 8 A. Stable Black Holes with Secondary Hair 8 B. Black Hole stability and a potential minimum length in quantum spacetime 12 V. Conclusions and Outlook 14 References 15

show abstract

Axion induced angular momentum reversal in Kerr-like black holes

Cited by 11 publications

References 30 publications

Stealth Ellis wormholes in Horndeski theories

Stealth Ellis wormholes in Horndeski theories

Slow-rotating black holes with potential in dynamical Chern-Simons modified gravitational theory

On Thermal Stability of Hairy Black Holes

Contact Info

Product

Resources

About