Safely smoothing spacetime: backreaction in relativistic cosmological simulations
Safely smoothing spacetime: backreaction in relativistic cosmological simulations
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DOI：
10.1088/1361-6382/aaeca5
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发表时间：
2017-06
影响因子：
3.5
通讯作者：
J. Adamek;C. Clarkson;David Daverio;R. Durrer;M. Kunz
中科院分区：
文献类型：
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作者：
J. Adamek;C. Clarkson;David Daverio;R. Durrer;M. Kunz
暗能量研究中一个持续的主题是它是否真的存在。人们经常声称，我们忽略了与大尺度结构平均化相关的影响，从而错误地计算了宇宙学模型。在牛顿近似中，这一点很清楚：没有效应。在完整的相对论图景中，这仍然是一个重要的悬而未决的问题，因为涉及复杂的数学。我们研究这个问题，使用数值N体模拟占所有相关的相对论效应，没有任何问题，从壳交叉。在这种情况下，我们第一次表明，从结构的反向反应可以不同的许多数量级取决于切片的时空选择平均。在最坏的情况下，在同步空间表面中进行平滑，校正可以达到10%或更多。然而，当在牛顿规范的恒时超曲面上平滑时，反反应贡献仍然小3-5个数量级。
A persistent theme in the study of dark energy is the question of whether it really exists or not. It is often claimed that we are mis-calculating the cosmological model by neglecting the effects associated with averaging over large-scale structures. In the Newtonian approximation this is clear: there is no effect. Within the full relativistic picture this remains an important open question, owing to the complex mathematics involved. We study this issue using numerical N-body simulations which account for all relevant relativistic effects without any problems from shell crossing. In this context we show for the first time that the backreaction from structure can differ by many orders of magnitude depending upon the slicing of spacetime one chooses to average over. In the worst case, where smoothing is carried out in synchronous spatial surfaces, the corrections can reach ten percent and more. However, when smoothing on the constant time hypersurface of the Newtonian gauge, backreaction contributions remain 3–5 orders of magnitude smaller.