# Cosmological renormalization of model parameters in the second-order perturbation theory

## TL;DR

This paper proposes that the cosmological tension regarding the Hubble constant can be resolved by applying a renormalization of model parameters derived from second-order perturbations, accounting for spatial averaging of fluctuations.

## Contribution

It introduces a method to address the Hubble tension by renormalizing model parameters through second-order perturbation analysis in the Lambda-CDM model.

## Key findings

- Renormalized parameters help reconcile Hubble constant measurements.
- Spatial averaging of second-order perturbations impacts cosmological parameter estimation.
- Potential solution to the Hubble tension problem.

## Abstract

It is shown that the serious problem on the cosmological tension between the direct measurements of the Hubble constant at present and the constant derived from the Planck measurements of the CMB anisotropies can be solved by considering the renormalized model parameters. They are deduced by taking the spatial average of second-order perturbations in the flat Lambda-CDM model, which includes random adiabatic fluctuations.