Modelling non-dust fluids in cosmology
Modelling non-dust fluids in cosmology
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DOI：
10.1088/1475-7516/2013/01/002
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发表时间：
2013-01-01
影响因子：
6.4
通讯作者：
Malik, Karim A.
中科院分区：
文献类型：
--
作者：
Christopherson, Adam J.;Carlos Hidalgo, Juan;Malik, Karim A.
目前，大多数结构形成的数值模拟使用牛顿引力。当模拟无压力的暗物质或“尘埃”时，这种方法在比宇宙视界小得多的尺度上给出了正确的结果，但在流体有压力的情况下，情况就不再是这样了。本文给出了牛顿微扰理论和宇宙学微扰理论中微扰的对应关系，给出了无压力物质的精确数学等价，并给出了有压力物质的相对论修正。作为一个例子，我们研究了具有非零压力扰动的标量场暗物质的情况。我们讨论了用牛顿数值模拟和微波背景玻尔兹曼码对该模型中的扰动进行演化时可能出现的一些问题。
Currently, most of the numerical simulations of structure formation use Newtonian gravity. When modelling pressureless dark matter, or 'dust', this approach gives the correct results for scales much smaller than the cosmological horizon, but for scenarios in which the fluid has pressure this is no longer the case. In this article, we present the correspondence of perturbations in Newtonian and cosmological perturbation theory, showing exact mathematical equivalence for pressureless matter, and giving the relativistic corrections for matter with pressure. As an example, we study the case of scalar field dark matter which features non-zero pressure perturbations. We discuss some problems which may arise when evolving the perturbations in this model with Newtonian numerical simulations and with CMB Boltzmann codes.