标题： 固定标量-高斯-博内引力的动力学演化 显示英文标题

标题： Fixing the dynamical evolution in scalar-Gauss-Bonnet gravity

摘要： 用合并致密天体双星产生的引力波数据检验引力的替代理论的一个主要障碍是这些理论的场方程的表述，它们在时间演化方面往往在数学上不适用。解决这些微妙缺陷的一种可能方法是固定方程的方法，该方法旨在控制解的高频模态的行为以及潜在的显著流向紫外模态。 这在引力塌缩中尤为令人担忧，在那里，即使黑洞的形成也可能不足以屏蔽可能出现这些病态区域的时空部分。 在这里，我们以标量-Gauss-Bonnet引力作为代表性例子（这是一种可能导致不适定动力学演化的理论，但具有引人入胜的静态黑洞物理性质）进行研究。我们在固定方程的方法下研究标量脉冲塌缩到黑洞的过程，将演化的早期阶段与未固定的理论进行比较，并将后期阶段与它的静态极限进行比较。 通过这种方法，我们可以超越原始理论中的问题区域，解析黑洞塌缩并连接到静态黑洞解。 因此，我们的方法可以被视为为原始理论提供了一个弱形式的完善，而观察到的行为也为考虑先前发现的黑洞解作为塌缩情景的自然结果提供了支持。 显示英文摘要

摘要： One of the major obstacles to testing alternative theories of gravity with gravitational-wave data from merging binaries of compact objects is the formulation of their field equations, which is often mathematically ill-suited for time evolutions. A possible way to address these delicate shortcomings is the fixing-the-equations approach, which was developed to control the behaviour of the high-frequency modes of the solutions and the potentially significant flow towards ultra-violet modes. This is particularly worrisome in gravitational collapse, where even black hole formation might be insufficient to shield regions of the spacetime where these pathologies might arise. Here, we focus (as a representative example) on scalar-Gauss-Bonnet gravity, a theory which can lead to ill-posed dynamical evolutions, but with intriguing stationary black hole physics. We study the spherical collapse of a scalar pulse to a black hole in the fixing-the-equations approach, comparing the early stages of the evolution with the unfixed theory, and the later stages with its stationary limit. With this approach, we are able to evolve past problematic regions in the original theory, resolve black hole collapse and connect with the static black hole solutions. Our method can thus be regarded as providing a weak completion of the original theory, and the observed behaviour lends support for considering previously found black hole solutions as a natural outcome of collapse scenarios.