We report on a numerical investigation of black hole evolution in an Einstein dilaton Gauss-Bonnet (EdGB) gravity theory where the Gauss-Bonnet coupling and scalar (dilaton) field potential are symmetric under a global change in sign of the scalar field (a 'Z2' symmetry). We find that for sufficiently small Gauss-Bonnet couplings Schwarzschild black holes are stable to radial scalar field perturbations, and are unstable to such perturbations for sufficiently large couplings. For the latter case, we provide numerical evidence that there is a band of coupling parameters and black hole masses where the end states are stable scalarized black hole solutions, in general agreement with the results of Macedo et al (2019 Phys. Rev. D 99 104041). For Gauss-Bonnet couplings larger than those in the stable band, we find that an 'elliptic region' forms outside of the black hole horizon, indicating the theory does not possess a well-posed initial value formulation in that regime.

中文翻译：

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球对称中Z ₂对称 EdGB 重力的动力学

我们报告了爱因斯坦膨胀高斯-博内 (EdGB) 引力理论中黑洞演化的数值研究，其中高斯-博内耦合和标量（膨胀）场势在标量场（a ' Z2' 对称性）。我们发现，对于足够小的 Gauss-Bonnet 耦合，Schwarzschild 黑洞对径向标量场扰动是稳定的，而对于足够大的耦合，则对这种扰动不稳定。对于后一种情况，我们提供了数值证据，表明存在耦合参数和黑洞质量带，其中终态是稳定的标量化黑洞解，与 Macedo 等人 (2019 Phys. Rev. D 99) 的结果大体一致104041）。对于大于稳定带中的高斯-博内耦合，我们发现 '