Constraining scalarization in scalar-Gauss-Bonnet gravity through binary pulsars

Danchev, Victor I.; Doneva, Daniela D.; Yazadjiev, Stoytcho S.

doi:10.48550/arxiv.2112.03869

Cited by 3 publications

(4 citation statements)

References 62 publications

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“…In the large regime, the scalar field derivative has peaks, which match the locations of the walls shown in Fig.1; a wall width is estimated as a peak width. For increasing µ and fixed , a wall moves towards a horizon and its width shrinks, in accordance with Eqs (22). and(23).…”

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confidence: 78%

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Shrouded black holes in Einstein-Gauss-Bonnet gravity

Babichev,

Emond,

Ramazanov

2022

Preprint

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We study black holes in a modified gravity scenario involving a scalar field quadratically coupled to the Gauss-Bonnet invariant. The scalar is assumed to be in a spontaneously broken phase at spatial infinity due to a bare Higgs-like potential. For a proper choice of sign, the non-minimal coupling to gravity leads to symmetry restoration near the black hole horizon, prompting the development of the scalar wall in its vicinity. The wall thickness depends on the bare mass of the scalar and can be much smaller than the Schwarzschild radius. In a weakly coupled regime, the quadratic coupling to the Gauss-Bonnet invariant effectively becomes linear, and no walls are formed. We find approximate analytical solutions for the scalar field in the test field regime, and obtain numerically static black hole solutions within this setup. We discuss cosmological implications of the model and show that it is fully consistent with the existence of an inflationary stage, unlike the spontaneous scalarization scenario assuming the opposite sign of the non-minimal coupling to gravity. Our model predicts the speed of gravitational waves to be extremely close to unity, -in a comfortable agreement with the observation of the GW170817 event and its electromagnetic counterpart.

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supporting

confidence: 78%

“…This model of scalarization is subject to stringent observational constraints [17] clearly demonstrating how deviations from GR caused by scalarization can be efficiently tested. Implications of scalar-Gauss-Bonnet coupling for black hole mergers [18,19,20,21] and binary pulsars [22] are currently under active investigation.…”

Section: Introductionmentioning

confidence: 99%

Shrouded black holes in Einstein-Gauss-Bonnet gravity

Babichev,

Emond,

Ramazanov

2022

Preprint

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“…The first condition can be imposed as the theory is invariant under ξ(ϕ) → ξ(ϕ) + cte, the second condition arises by requiring the existence of GR solutions and third condition can be imposed without loss of generality while maintaining a tachyonic instability in the large curvature regime. An example of such a coupling, commonly used in the literature [6,11,14,47,[68][69][70][71], and that we shall study here is the 'quadratic exponential' coupling…”

Section: Esgb Gravity: Field Equations and The Shape Of ξ (ϕ)mentioning

confidence: 99%

Exploring the small mass limit of stationary black holes in theories with Gauss–Bonnet terms

Fernandes

Mulryne

Delgado

2022

Class. Quantum Grav.

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In this work we examine the small mass limit of black holes, with and without spin, in theories where a scalar field is non-minimally coupled to a Gauss-Bonnet term. First, we provide an analytical example for a theory where a static closed-form solution with a small mass limit is known, and later use analytical and numerical techniques to explore this limit in standard scalar-Gauss-Bonnet theories with dilatonic, linear and quadratic-exponential couplings. In most cases studied here, we find an inner singularity that overlaps with the event horizon of the static black hole as the small mass limit is reached. Moreover, since solutions in this limit possess a non-vanishing Hawking temperature, a naked singularity is expected to be reached through evaporation, raising questions concerning the consistency of these theories altogether. On the other hand, we provide for the first time in this context an example of a coupling where the small mass limit is never reached, thus preferred from the point of view of cosmic censorship. Finally, we consider black holes with spin and numerically investigate how this changes the picture, using these to place the tightest upper bounds to date on the coupling constant for the dilatonic and linear theories, with $\sqrt{\overline{\alpha}} < 1$ km.

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“…The first condition can be imposed as the theory is invariant under ξ(φ) → ξ(φ) + cte, the second condition arises by requiring the existence of GR solutions and third condition can be imposed without loss of generality while maintaning a tachyonic instability in the large curvature regime. An example of such a coupling, commonly used in the literature [4,9,12,[53][54][55][56][57], and that we shall study here is the "quadratic exponential" coupling…”

Section: Einstein-scalar-gauss-bonnet Gravity: Field Equations and Th...mentioning

confidence: 99%

Exploring the Small Mass Limit of Stationary Black Holes in Theories with Gauss-Bonnet Terms

Fernandes¹,

Mulryne²,

Delgado³

2022

Preprint

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Constraining scalarization in scalar-Gauss-Bonnet gravity through binary pulsars

Cited by 3 publications

References 62 publications

Shrouded black holes in Einstein-Gauss-Bonnet gravity

Shrouded black holes in Einstein-Gauss-Bonnet gravity

Exploring the small mass limit of stationary black holes in theories with Gauss–Bonnet terms

Exploring the Small Mass Limit of Stationary Black Holes in Theories with Gauss-Bonnet Terms

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