标题： 动量流在黑洞双星中：II. 质量相等、对头合并且自旋方向相反的数值模拟 显示英文标题

标题： Momentum flow in black-hole binaries: II. Numerical simulations of equal-mass, head-on mergers with antiparallel spins

摘要： 从双黑洞（BBH）模拟中提取科学的研究通常采用“散射矩阵”观点：给定双黑洞的初始参数，最终黑洞的参数和发出的引力波形是什么？ 相反，我们使用BBH模拟来探索弯曲时空的非线性动力学。 专注于具有横向反平行自旋的BBH的正面坠落、合并和回音阶段，我们数值地研究了黑洞之间以及周围时空之间的动量流动。 我们使用平直时空中的Landau-Lifshitz场论形式的广义相对论来定义和计算视界外的场能密度和场动量以及视界内的能量和动量，并将每个似是而非视界和事件视界的有效速度定义为其包含的动量与其包含的质量-能量的比值。 我们发现视界的有效速度和坐标速度之间出人意料地一致。 为了研究我们结果的规范依赖性，我们将伪谱和移动点演化的物理相似初始数据进行比较；尽管谱和点模拟使用不同的规范条件，但我们在这两种情况下发现结果非常一致。 我们还将我们的模拟与后牛顿轨迹和近场能量动量进行了比较。 [摘要已缩写；完整摘要还提到了其他结果。] 显示英文摘要

摘要： Research on extracting science from binary-black-hole (BBH) simulations has often adopted a "scattering matrix" perspective: given the binary's initial parameters, what are the final hole's parameters and the emitted gravitational waveform? In contrast, we are using BBH simulations to explore the nonlinear dynamics of curved spacetime. Focusing on the head-on plunge, merger, and ringdown of a BBH with transverse, antiparallel spins, we explore numerically the momentum flow between the holes and the surrounding spacetime. We use the Landau-Lifshitz field-theory-in-flat-spacetime formulation of general relativity to define and compute the density of field energy and field momentum outside horizons and the energy and momentum contained within horizons, and we define the effective velocity of each apparent and event horizon as the ratio of its enclosed momentum to its enclosed mass-energy. We find surprisingly good agreement between the horizons' effective and coordinate velocities. To investigate the gauge dependence of our results, we compare pseudospectral and moving-puncture evolutions of physically similar initial data; although spectral and puncture simulations use different gauge conditions, we find remarkably good agreement for our results in these two cases. We also compare our simulations with the post-Newtonian trajectories and near-field energy-momentum. [Abstract abbreviated; full abstract also mentions additional results.]