Multi-scale perturbation theory. Part I. Methodology and leading-order bispectrum corrections in the matter-dominated era

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dc.contributor.authorClarksona, Chris
dc.contributor.authorGallagher, Christopher S.
dc.contributor.authorClifton, Timothy
dc.date.accessioned2021-02-18T11:24:24Z
dc.date.available2021-02-18T11:24:24Z
dc.date.issued2020
dc.description.abstractTwo-parameter perturbation theory is a scheme tailor-made to consistently include nonlinear density contrasts on small scales (< 100 Mpc), whilst retaining a traditional approach to cosmological perturbations in the long-wavelength universe. In this paper we study the solutions that arise from this theory in a spatially-flat dust-filled cosmology, and what these imply for the bispectrum of matter. This is achieved by using Newtonian perturbation theory to model the gravitational fields of nonlinear structures in the quasi-linear regime, and then using the resulting solutions as source terms for the cosmological equations. We find that our approach results in the leading-order part of the cosmological gravitational potentials being identical to those that result from standard cosmological perturbation theory at second-order, while the dark matter bispectrum itself yields some differences on Hubble scales. This demonstrates that our approach is sufficient to capture most leading-order relativistic effects, but within a framework that is far easier to generalize. We expect this latter property to be particularly useful for calculating leading-order relativistic corrections to the matter power spectrum, as well as for deriving predictions for relativistic effects in alternative theories of gravity.en_US
dc.identifier.citationClarksona, C. et al. (2020). Multi-scale perturbation theory. Part I. Methodology and leading-order bispectrum corrections in the matter-dominated era. Journal of Cosmology and Astroparticle Physics ,2020(03)en_US
dc.identifier.urihttp://doi.org/10.1088/1475-7516/2020/03/011
dc.identifier.urihttp://hdl.handle.net/10566/5958
dc.language.isoenen_US
dc.publisherIOP Publishing Ltden_US
dc.subjectCosmological perturbation theoryen_US
dc.subjectGravityen_US
dc.subjectNon-gaussianityen_US
dc.subjectPower spectrumen_US
dc.subjectNonlinear densityen_US
dc.titleMulti-scale perturbation theory. Part I. Methodology and leading-order bispectrum corrections in the matter-dominated eraen_US
dc.typeArticleen_US

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