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arXiv 1408.2995astro-ph.COhep-ph
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大质量中微子的结构形成:超越线性理论

Structure formation with massive neutrinos: going beyond linear theory

Diego Blas, Mathias Garny, Thomas Konstandin, Julien Lesgourgues

摘要:

我们计算非线性修正的物质功率谱考虑到时间和尺度依赖的自由流长度的中微子。我们采用了一种混合方案,匹配完整的玻尔兹曼层次结构的一个有效的两流体描述在中间红移。中微子分量的非线性考虑到使用的时间流框架的扩展。我们指出,这补救了一个虚假的行为,发生时忽略中微子的非线性项。这种行为与短模如何有效地从长模中解耦有关,如果中微子被线性处理,则可以追溯到违反动量守恒。此外,我们比较我们的结果在下一个领先的顺序,以各种其他方法和量化的准确性的流体描述。由于短模式的正确解耦行为,双流体方案是一个合适的起点,以计算更高阶的扰动或重定方法。

英文摘要:

We compute non-linear corrections to the matter power spectrum taking the time- and scale-dependent free-streaming length of neutrinos into account. We adopt a hybrid scheme that matches the full Boltzmann hierarchy to an effective two-fluid description at an intermediate redshift. The non-linearities in the neutrino component are taken into account by using an extension of the time-flow framework. We point out that this remedies a spurious behaviour that occurs when neglecting non-linear terms for neutrinos. This behaviour is related to how efficiently short modes decouple from long modes and can be traced back to the violation of momentum conservation if neutrinos are treated linearly. Furthermore, we compare our results at next to leading order to various other methods and quantify the accuracy of the fluid description. Due to the correct decoupling behaviour of short modes, the two-fluid scheme is a suitable starting point to compute higher orders in perturbations or for resummation methods.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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