2017/08/31 by Krzysztof Bolejko · 1 citation
Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Classical mechanics #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Curvature #Dark energy #De Sitter universe #Einstein field equations #Galaxies: Formation, Evolution, Phenomena #Geometry #Gravitation #Mathematical physics #Metric expansion of space #Physics #Shape of the universe #Theoretical physics #Universe #astro-ph.CO #gr-qc
paper · pdf · doi:10.1088/1361-6382/aa9d32
26 pages, 5 figures; accepted for publication in Class. Quantum Grav
openalex publication_date 2017/11/27 · arxiv created 2017/12/07 · arxiv updated 2017/12/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Relativistic numerical cosmology is most often based either on the exact solutions of the Einstein equations, or perturbation theory, or weak-field limit, or the BSSN formalism. The silent universe provides an alternative approach to investigate relativistic evolution of cosmological systems. The silent universe is based on the solution of the Einstein equations in 1 + 3 comoving coordinates with additional constraints imposed. These constraints include: the gravitational field is sourced by dust and cosmological constant only, both rotation and magnetic part of the Weyl tensor vanish, and the shear is diagnosable. This paper describes the code simsilun (free software distributed under the terms of the reposi General Public License), which implements the equations of the silent universe. The paper also discusses applications of the silent universe and it uses the Millennium simulation to set up the initial conditions for the code simsilun . The simulation obtained this way consists of 16 777 216 worldlines, which are evolved from z = 80 to z = 0. Initially, the mean evolution (averaged over the whole domain) follows the evolution of the background ΛCDM model. However, once the evolution of cosmic structures becomes nonlinear, the spatial curvature evolves from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mstyle displaystyle="false"> <mml:msub> <mml:mo mathvariant="normal">Ω</mml:mo> <mml:mi>K</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> </mml:mstyle> </mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mstyle displaystyle="false"> <mml:msub> <mml:mo mathvariant="normal">Ω</mml:mo> <mml:mi>K</mml:mi> </mml:msub> <mml:mo>≈</mml:mo> <mml:mn>0.1</mml:mn> </mml:mstyle> </mml:math> at the present day. The emergence of the spatial curvature is associated with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mstyle displaystyle="false"> <mml:msub> <mml:mo mathvariant="normal">Ω</mml:mo> <mml:mi>M</mml:mi> </mml:msub> </mml:mstyle> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mstyle displaystyle="false"> <mml:msub> <mml:mo mathvariant="normal">Ω</mml:mo> <mml:mi mathvariant="normal">Λ</mml:mi> </mml:msub> </mml:mstyle> </mml:math> being smaller by approximately 0.05 compared to the ΛCDM.