本文详细研究了修改引力理论中chameleon模型的线性和非线性结构形成，通过4参数通用参数化进行模拟，共进行了65次N体模拟，包括标准 LCDM 模型。结果显示，chameleon的筛查机制比其他机制如dilaton和symmetron更高效，尤其是在高密度区域和早期宇宙。这些发现揭示了chameleon参数空间中值得深入研究的部分，并为未来工作提供了指导。
摘要：
In this work we systematically study the linear and nonlinear structure formation in chameleon theories of modified gravity, using a generic parameterisation which describes a large class of models using only 4 parameters. For this we have modified the N-body simulation code ECOSMOG to perform a total of 65 simulations for different models and parameter values, including the default LCDM. These simulations enable us to explore a significant portion of the parameter space. We have studied the effects of modified gravity on the matter power spectrum and mass function, and found a rich and interesting phenomenology where the difference with the LCDM paradigm cannot be reproduced by a linear analysis even on scales as large as k~0.05h/Mpc, since the latter incorrectly assumes that the modification of gravity depends only on the background matter density. Our results show that the chameleon screening mechanism is significantly more efficient than other mechanisms such as the dilaton and symmetron, especially in high-density regions and at early times, and can serve as a guidance to determine the parts of the chameleon parameter space which are cosmologically interesting and thus merit further studies in the future.
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