Perturbation theory remixed: Improved nonlinearity modeling beyond standard perturbation theory

Zhenyuan Wang, Donghui Jeong, Atsushi Taruya, Takahiro Nishimichi, Ken Osato

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We present a novel nEPT (nth-order Eulerian perturbation theory) scheme to model the nonlinear density field by the summation up to nth-order density fields in perturbation theory. The obtained analytical power spectrum shows excellent agreement with the results from all 20 Dark-Quest suites of N-body simulations spreading over a broad range of cosmologies. The agreement is much better than the conventional two-loop standard perturbation theory and would reach out to kmax≃0.4 h/Mpc at z=3 for the best-fitting Planck cosmology, without any free parameters. We find that the nEPT results, particularly for n>4, depend sensitively on the grid size, but that can be removed by employing an effective field theory-type fitting function. The method can accelerate the forward modeling of the nonlinear cosmological density field, an indispensable probe of cosmic mysteries such as inflation, dark energy, and dark matter.

Original languageEnglish (US)
Article number103534
JournalPhysical Review D
Volume107
Issue number10
DOIs
StatePublished - May 15 2023

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

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