膜致重力II中的大尺度结构。数值模拟
Large-Scale Structure in Brane-Induced Gravity II. Numerical Simulations
摘要：
我们使用N体模拟来研究膜诱导引力中非线性结构的形成，发展了一种新的方法，需要交替使用快速傅立叶变换和松弛。这使我们能够计算非线性物质的功率谱和双谱，晕质量函数和晕偏置。从模拟结果中，我们证实了预期的分析参数的基础上，Vainshtein机制不按预期运行，密度功率谱接近标准重力在一个修改后的背景演变的非线性制度。跃迁很宽，没有很好的Vainshtein标度，但大致对应于红移z=1时的k_*~ 2和z=0时的k_*~ 1。我们检查，虽然外在曲率波动非线性，和膜弯曲模式C的动力学接受重要的非线性修正，这种模式得到抑制相比，密度扰动，有效地从标准重力部门解耦。同时，与C有关的度规微扰没有违反弱场极限。我们发现我们的测量和预测的非线性功率谱在纸我，依赖于重整化的线性谱由于在修改后的重力部门的非线性之间有很好的协议。对质量函数的类似预测显示了正确的趋势。我们的模拟也证实了在论文I中预测的双谱组态依赖性的诱导变化。
英文摘要：
We use N-body simulations to study the nonlinear structure formation in brane-induced gravity, developing a new method that requires alternate use of Fast Fourier Transforms and relaxation. This enables us to compute the nonlinear matter power spectrum and bispectrum, the halo mass function, and the halo bias. From the simulation results, we confirm the expectations based on analytic arguments that the Vainshtein mechanism does operate as anticipated, with the density power spectrum approaching that of standard gravity within a modified background evolution in the nonlinear regime. The transition is very broad and there is no well defined Vainshtein scale, but roughly this corresponds to k_*~ 2 at redshift z=1 and k_*~ 1 at z=0. We checked that while extrinsic curvature fluctuations go nonlinear, and the dynamics of the brane-bending mode C receives important nonlinear corrections, this mode does get suppressed compared to density perturbations, effectively decoupling from the standard gravity sector. At the same time, there is no violation of the weak field limit for metric perturbations associated with C. We find good agreement between our measurements and the predictions for the nonlinear power spectrum presented in paper I, that rely on a renormalization of the linear spectrum due to nonlinearities in the modified gravity sector. A similar prediction for the mass function shows the right trends. Our simulations also confirm the induced change in the bispectrum configuration dependence predicted in paper I.
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