AI 中文总结
该研究利用KGB-evolution代码计算多种引力场探测可观测量，发现KGB模型与k本质模型在引力势演化及ISW-RS、弱引力透镜等信号上存在显著尺度依赖偏差，需考虑非线性效应以获得可靠理论预测。
AI 中文摘要
我们研究动力学引力编织（Kinetic Gravity Braiding, KGB）模型在沿过去光锥构建的相对论性宇宙学探测中的观测特征。利用相对论性N体代码KGB-evolution，我们生成光锥输出并计算多个直接探测引力场的可观测量，包括弱引力透镜会聚、夏皮罗时间延迟、综合萨克斯-沃尔夫及里斯-夏马（ISW-RS）效应、引力红移。我们构建这些量的全天图和角功率谱，并与k本质（k-essence）模型及线性微扰理论的预测进行比较。我们发现，标量场与度规之间的导数耦合会修改引力势的振幅和时间演化，产生从百分之几到百分之几十的尺度依赖偏差。特别地，ISW-RS信号表现出最大的分数响应：在ISW主导区域，魏尔势的较慢衰减会压低KGB信号，而在更高多极矩处，非线性演化逆转了这一趋势，与k本质相比产生百分之几十的差异。弱引力透镜也提供了强有力的互补探测，对于此处考虑的模型，其在小尺度上表现出与k本质预测的明显偏差，在多极矩ℓ~10²-10³处增强幅度达~10%-12%。我们的结果表明，线性微扰理论可准确描述大尺度行为，而非线性效应在更小尺度上变得重要，尤其对ISW-RS信号，对会聚的影响稍弱，因此必须纳入以获得可靠的理论预测。
英文摘要
We study the observational signatures of kinetic gravity braiding (KGB) models in relativistic cosmological probes constructed along the past light cone. Using the relativistic $N$-body code KGB-evolution, we generate light-cone outputs and compute several observables that directly probe the gravitational field, including weak gravitational lensing convergence, Shapiro time delay, the integrated Sachs-Wolfe and Rees-Sciama (ISW-RS) effects, and gravitational redshift. Full-sky maps and angular power spectra of these quantities are constructed and compared with $k$-essence models and predictions from linear perturbation theory. We find that the derivative coupling between the scalar field and the metric modifies both the amplitude and the time evolution of the gravitational potentials, producing scale-dependent deviations ranging from a few percent to tens of percent. In particular, the ISW-RS signal exhibits the largest fractional response, as the slower decay of the Weyl potential suppresses the KGB signal in the ISW-dominated regime, whereas nonlinear evolution reverses this trend at higher multipoles, producing differences of tens of percent relative to $k$-essence. Weak gravitational lensing also provides a strong complementary probe and, for the model considered here, exhibits clear deviations from the $k$-essence prediction at small scales with enhancements up to $\sim 10$-$12\%$ at multipoles $\ell \sim 10^2$-$10^3$. Our results show that linear perturbation theory accurately describes the large-scale behaviour, while nonlinear effects become important at smaller scales, particularly for the ISW-RS signal and, more moderately, for the convergence, and must therefore be included for reliable theoretical predictions.
Comments38 pages, 13 figures, 3 tables
