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arXiv · 1807.01711

Einstein's Universe: Cosmological structure formation in numerical relativity

Hayley J. Macpherson·Daniel J. Price·Paul D. Lasky
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Abstract

We perform large-scale cosmological simulations that solve Einstein's equations directly via numerical relativity. Starting with initial conditions sampled from the cosmic microwave background, we track the emergence of a cosmic web without the need for a background cosmology. We measure the backreaction of large-scale structure on the evolution of averaged quantities in a matter-dominated universe. Although our results are preliminary, we find the global backreaction energy density is of order $10^{-8}$ compared to the energy density of matter in our simulations, and is thus unlikely to explain accelerating expansion under our assumptions. Sampling scales above the homogeneity scale of the Universe ($100-180\,h^{-1}$Mpc), in our chosen gauge, we find $2-3\%$ variations in local spatial curvature.

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Hayley J. Macpherson, Daniel J. Price, Paul D. Lasky. 2018-07-04. Einstein's Universe: Cosmological structure formation in numerical relativity. https://doi.org/10.1103/physrevd.99.063522

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