General Relativity solutions in modified gravity

Motohashi, Hayato; Minamitsuji, Masato

doi:10.1016/j.physletb.2018.04.041

Cited by 64 publications

(71 citation statements)

References 119 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The coupling functions satisfy F 0 = F 1 = 0 and A 1 + A 2 = 0, which is consistent with the condition for the "case 1" of Ref. [25], and also the condition for the existence of general relativity solution in the limit of constant scalar field [51]. We emphasize that here we derived the Schwarzschild solution without assuming it a priori.…”

Section: Exact Solutions For the Case With F0 =supporting

confidence: 80%

Linear stability analysis of hairy black holes in quadratic degenerate higher-order scalar-tensor theories: Odd-parity perturbations

2019

Self Cite

View full text Add to dashboard Cite

We study static spherically symmetric black hole solutions with a linearly time-dependent scalar field and discuss their linear stability in the shift-and reflection-symmetric subclass of quadratic degenerate higher-order scalar-tensor (DHOST) theories. We present the explicit forms of the reduced system of background field equations for a generic theory within this subclass. Using the reduced equations of motion, we show that in several cases the solution is forced to be of the Schwarzschild or Schwarzschild-(anti-)de Sitter form. We consider odd-parity perturbations around general static spherically symmetric black hole solutions and derive the concise criteria for the black holes to be stable. Our analysis also covers the case with a static or constant profile of the scalar field.*1 Yet, there have been attempts to further extend the framework by relaxing the requirement so that the degenerate property holds only in the unitary gauge [21][22][23].

show abstract

Section: Exact Solutions For the Case With F0 =supporting

confidence: 80%

Linear stability analysis of hairy black holes in quadratic degenerate higher-order scalar-tensor theories: Odd-parity perturbations

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Note that an analysis similar to the one presented here has been conducted in Ref. [62] for multiscalar-tensor theories, but with more restrictive assumptions that appear to exclude case II.…”

Section: B Gr As a Solution Of Horndeski Gravitymentioning

confidence: 95%

Spontaneous scalarization in generalized scalar-tensor theory

et al. 2019

View full text Add to dashboard Cite

Spontaneous scalarization is a mechanism that endows relativistic stars and black holes with a nontrivial configuration only when their spacetime curvature exceeds some threshold. The standard way to trigger spontaneous scalarization is via a tachyonic instability at the linear level, which is eventually quenched due to the effect of nonlinear terms. In this paper, we identify all of the terms in the Horndeski action that contribute to the (effective) mass term in the linearized equations and, hence, can cause or contribute to the tachyonic instability that triggers scalarization.

show abstract

“…The well known stealth Schwarzschild solution associated to a constant kinetic term was considered in several works [34][35][36][37][38][39][40][41] and provides the simplest solution for such higher order theories. Conditions on the coupling functions of the DHOST Lagrangian for admitting such stealth black hole solutions have been derived in [42,43].…”

Section: Generating Black Hole Solutions Beyond the Stealth Sectormentioning

confidence: 99%

Hairy black holes in DHOST theories: exploring disformal transformation as a solution generating method

Achour

Liu

Mukohyama

2020

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

Solutions-generating methods based on field redefinitions, such as conformal mapping, play an important role in investigating exact solutions in modified gravity. In this work, we explore the possibility to use disformal field redefinitions to investigate new regions of the solution space of DHOST theories, and present new hairy black holes solutions beyond the stealth sector. The crucial ingredient is to find suitable seed solutions to generate new exact ones for DHOST theories. We first consider a seed solution of the Einstein-Scalar system describing a naked singularity. Under suitable assumptions, we derive a no-go result showing that no black hole solution can be constructed from such a seed GR solution. Then, taking into account the stability of each three degeneracy classes of quadratic DHOST theories under a general disformal mapping, we consider two kinds of known black hole solutions as seed configurations: the Schwarzschild stealth solution and the non-stealth Reissner-Nordstrom like solution. Restricting our considerations to invertible disformal transformations, we show that building new hairy black hole solutions from the stealth solution associated to a constant kinetic term is also quite constrained. We obtain new solutions which either are stealth or describe asymptotically locally flat black holes with a deficit solid angle. However, starting from the non-stealth seed solution associated to a non constant kinetic term, we show that a disformal transformation can introduce rather general modifications of the exterior geometry. Finally, we consider the construction of minimally modified hairy black hole solutions using a small disformal transformation. Further applications of this solution generating method should allow to provide new hairy rotating black hole solutions beyond the stealth sector, as well as minimally modified GR solutions useful for phenomenological investigations of compact objects beyond GR.

show abstract

General Relativity solutions in modified gravity

Cited by 64 publications

References 119 publications

Linear stability analysis of hairy black holes in quadratic degenerate higher-order scalar-tensor theories: Odd-parity perturbations

Linear stability analysis of hairy black holes in quadratic degenerate higher-order scalar-tensor theories: Odd-parity perturbations

Spontaneous scalarization in generalized scalar-tensor theory

Hairy black holes in DHOST theories: exploring disformal transformation as a solution generating method

Contact Info

Product

Resources

About