Cosmological Perturbations and the Running Cosmological Constant Model

TL;DR

This paper investigates the running cosmological constant model's impact on matter density fluctuations, growth rate, and structure formation, comparing predictions with observational data to assess its viability against the standard Lambda CDM model.

Contribution

It introduces a detailed analysis of the RCC model using linear perturbations and demonstrates its potential to distinguish itself from Lambda CDM through structure formation predictions.

Findings

RCC model predicts higher cluster numbers than Lambda CDM.

Increasing the parameter ν enhances structure growth in the RCC model.

Perturbation theory effectively differentiates RCC from standard cosmology.

Abstract

We study the matter density fluctuations in the running cosmological constant (RCC) model using linear perturbations in the longitudinal gauge. Using this observable we calculate the growth rate of structures and the matter power spectrum, and compare them with the $SDSS$ data and other available data of the linear growth rate. The distribution of collapsed structures may also constraints models of dark energy. It is shown that RCC model enhances departures from the $\Lambda CDM$ model for both cluster number and cumulative cluster number predicted. In general increasing the characteristic parameter $\nu$ leads to significant growth of the cluster number. In general, we found that the theory of perturbations provides a good tool to distinguish the new model $RCC$ of the standard cosmological model $\Lambda CDM$.