Testing the cosmological Poisson equation in a model-independent way
We show how one can test the cosmological Poisson equation by requiring only the validity of three main assumptions: the energy-momentum conservation equations of matter, the equivalence principle, and the cosmological principle. We first point out that one can only measure the combination M≡Ωm(0)μ,...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
June 2024
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| In: |
Physics letters
Year: 2024, Volume: 853, Pages: 1-9 |
| ISSN: | 1873-2445 |
| DOI: | 10.1016/j.physletb.2024.138647 |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.1016/j.physletb.2024.138647 Verlag, kostenfrei, Volltext: https://www.sciencedirect.com/science/article/pii/S0370269324002053 
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| Author Notes: | Ziyang Zheng, Ziad Sakr, Luca Amendola |
| Summary: | We show how one can test the cosmological Poisson equation by requiring only the validity of three main assumptions: the energy-momentum conservation equations of matter, the equivalence principle, and the cosmological principle. We first point out that one can only measure the combination M≡Ωm(0)μ, where μ quantifies the deviation of the Poisson equation from the standard one and Ωm(0) is the fraction of matter density at present. Then we employ a recent model-independent forecast for the growth rate f(z) and the expansion rate E(z) to obtain constraints on M for a survey that approximates a combination of the Dark Energy Spectroscopic Instrument (DESI) and Euclid. We conclude that a constant M can be measured with a relative error σM=4.5%, while if M is arbitrarily varying in redshift, it can be measured only to within 13.4% (1 σ c.l.) at redshift z=0.9, and 15-22% up to z=1.5. We also project our constraints on some parametrizations of M proposed in literature, while still maintaining model-independence for the background expansion, the power spectrum shape, and the non-linear corrections. Generally speaking, as expected, we find much weaker model-independent constraints than found so far for such models. This means that the cosmological Poisson equation remains quite open to various alternative gravity and dark energy models. |
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| Item Description: | Online verfügbar: 16. April 2024, Artikelversion: 18. April 2024 Gesehen am 18.09.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1873-2445 |
| DOI: | 10.1016/j.physletb.2024.138647 |