Browsing by Subject "Alternative gravity theories"

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    Comment on “Einstein-Gauss-Bonnet Gravity in four-dimensional spacetime”
    (American Physical Society, 2020) Gürses, Metin; Şişman, T. Ç.; Tekin, B.
    We summarize our proof that the "Einstein-Gauss-Bonnet Gravity in Four-Dimensional Spacetime" introduced in Phys. Rev. Lett. 124, 081301 (2020) does not have consistent field equations, as such the theory does not exist. The proof is given in both the metric and the first order formalisms.
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    Non-Einsteinian black holes in generic 3D gravity theories
    (American Physical Society, 2019) Gürses, Metin; Şişman, T. Ç.; Tekin, B.
    The Bañados-Teitelboim-Zanelli (BTZ) black hole metric solves the three-dimensional Einstein’s theory with a negative cosmological constant as well as all the generic higher derivative gravity theories based on the metric; as such it is a universal solution. Here, we find, in all generic higher derivative gravity theories, new universal non-Einsteinian solutions obtained as Kerr-Schild type deformations of the BTZ black hole. Among these, the deformed nonextremal BTZ black hole loses its event horizon while the deformed extremal one remains intact as a black hole in any generic gravity theory.