Einstein's Universe

Cosmological structure formation in numerical relativity

Hayley J. Macpherson, Daniel J. Price, Paul D. Lasky

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

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.

Original languageEnglish
Article number063522
Number of pages18
JournalPhysical Review D
Volume99
Issue number6
DOIs
Publication statusPublished - 15 Mar 2019

Keywords

  • universe
  • luminosity distance
  • models

Cite this

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title = "Einstein's Universe: Cosmological structure formation in numerical relativity",
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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Einstein's Universe : Cosmological structure formation in numerical relativity. / Macpherson, Hayley J.; Price, Daniel J.; Lasky, Paul D.

In: Physical Review D, Vol. 99, No. 6, 063522, 15.03.2019.

Research output: Contribution to journalArticleResearchpeer-review

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T2 - Cosmological structure formation in numerical relativity

AU - Macpherson, Hayley J.

AU - Price, Daniel J.

AU - Lasky, Paul D.

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AB - 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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