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arXiv · 2209.00033

Perturbation Theory Remixed: Improved Nonlinearity Modeling beyond Standard Perturbation Theory

Zhenyuan Wang·Donghui Jeong·Atsushi Taruya·Takahiro Nishimichi·Ken Osato
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Abstract

We present a novel $n$EPT ($n$th-order Eulerian Perturbation Theory) scheme to model the nonlinear density field by the summation up to $n$th-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 $k_{\rm max}\simeq 0.4~h/{\rm Mpc}$ at $z=3$ for the best-fitting Planck cosmology, without any free parameters. The method can accelerate the forward modeling of the non-linear cosmological density field, an indispensable probe of cosmic mysteries such as inflation, dark energy, and dark matter.

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Zhenyuan Wang, Donghui Jeong, Atsushi Taruya, Takahiro Nishimichi, Ken Osato. 2022-08-31. Perturbation Theory Remixed: Improved Nonlinearity Modeling beyond Standard Perturbation Theory. https://doi.org/10.1103/physrevd.107.103534

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