Intrinsic time in Friedmann-Robertson-Walker universe

TL;DR

This paper investigates the use of intrinsic global time in Friedmann-Robertson-Walker models and explores its applicability to non-symmetric cases with linear metric perturbations, finding scalar perturbations affect energy density while vector and tensor do not.

Contribution

It extends the concept of intrinsic global time to non-symmetric models by analyzing linear metric perturbations and their effects on cosmological dynamics.

Findings

Scalar perturbations modify effective energy density in the Hubble law.

Vector and tensor perturbations do not influence the intrinsic time.

Intrinsic time remains applicable in linear perturbation regimes.

Abstract

A global intrinsic time in Friedmann - Robertson - Walker models is proportional to a scaling factor of the spatial metric. The aim of the paper is to study an applicability of the intrinsic global time chosen to nearest non-symmetric cases by taking into account linear metric perturbations. Scalar linear perturbations add some corrections to the effective energy density in the Hubble law. The metric vector and tensor perturbations in linear approximation do not influence the intrinsic time.