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Kinetic field theory: Non-linear cosmic power spectra in the mean-field approximation

by Matthias Bartelmann, Johannes Dombrowski, Sara Konrad, Elena Kozlikin, Robert Lilow, Carsten Littek, Christophe Pixius, Felix Fabis

Submission summary

As Contributors: Matthias Bartelmann
Arxiv Link: https://arxiv.org/abs/2011.04979v1 (pdf)
Date submitted: 2020-11-19 11:37
Submitted by: Bartelmann, Matthias
Submitted to: SciPost Physics
Academic field: Physics
Specialties:
  • Gravitation, Cosmology and Astroparticle Physics
Approach: Theoretical

Abstract

We use the recently developed Kinetic Field Theory (KFT) for cosmic structure formation to show how non-linear power spectra for cosmic density fluctuations can be calculated in a mean-field approximation to the particle interactions. Our main result is a simple, closed and analytic, approximate expression for this power spectrum. This expression has two parameters characterising non-linear structure growth which can be calibrated within KFT itself. Using this self-calibration, the non-linear power spectrum agrees with results obtained from numerical simulations to within typically $\lesssim10\,\%$ up to wave numbers $k\lesssim10\,h\,\mathrm{Mpc}^{-1}$ at redshift $z = 0$. Adjusting the two parameters to optimise agreement with numerical simulations, the relative difference to numerical results shrinks to typically $\lesssim 5\,\%$. As part of the derivation of our mean-field approximation, we show that the effective interaction potential between dark-matter particles relative to Zel'dovich trajectories is sourced by non-linear cosmic density fluctuations only, and is approximately of Yukawa rather than Newtonian shape.

Current status:
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Submission 2011.04979v1 on 19 November 2020

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