Renormalization group and UV completion of cosmological perturbations: Gravitational collapse as a critical phenomenon

Autor(en)

Cornelius Rampf, Oliver Hahn

Abstrakt

Cosmological perturbation theory is known to converge poorly for predicting the spherical collapse and void evolution of collisionless matter. Using the exact parametric solution as a testing ground, we develop two asymptotic methods in spherical symmetry that resolve the gravitational evolution to much higher accuracy than Lagrangian perturbation theory (LPT), which is the current gold standard in the literature. One of the methods selects a stable fixed-point solution of the renormalization-group flow equation, thereby predicting already at the leading order the critical exponent of the phase transition to collapsed structures. The other method completes the truncated LPT series far into the UV regime, by adding a nonanalytic term that captures the critical nature of the gravitational collapse. We find that the UV method most accurately resolves the evolution of the nonlinear density as well as its one-point probability distribution function. Similarly accurate predictions are achieved with the renormalization-group method, especially when paired with Padé approximants. Further, our results yield new, very accurate, formulas to relate linear and nonlinear density contrasts. Finally, we chart possible ways on how to adapt our methods to the case of cosmological random field initial conditions.

Organisation(en)

Institut für Mathematik, Institut für Astrophysik

Journal

Physical Review D

Band

107

ISSN

2470-0010

DOI

https://doi.org/10.1103/PhysRevD.107.023515

Publikationsdatum

01-2023

Peer-reviewed

Ja

ÖFOS 2012

103044 Kosmologie, 103019 Mathematische Physik

ASJC Scopus Sachgebiete

Nuclear and High Energy Physics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c62c4be5-b0a8-45fd-b420-de0526a2444a