`Standard' Cosmological model & beyond with CMB

TL;DR

Recent advances in observational cosmology, especially CMB measurements, have refined the standard model parameters and confirmed key early universe principles, while also opening avenues to explore new physics beyond the standard cosmological paradigm.

Contribution

This paper reviews the progress in CMB observations and their implications for the standard cosmological model and early universe physics, highlighting recent findings and future directions.

Findings

Precise parameter estimation of the standard model.

Confirmation of inflationary predictions.

Evidence for physics beyond the standard model.

Abstract

Observational Cosmology has indeed made very rapid progress in the past decade. The ability to quantify the universe has largely improved due to observational constraints coming from structure formation Measurements of CMB anisotropy and, more recently, polarization have played a very important role. Besides precise determination of various parameters of the `standard' cosmological model, observations have also established some important basic tenets that underlie models of cosmology and structure formation in the universe -- `acausally' correlated initial perturbations in a flat, statistically isotropic universe, adiabatic nature of primordial density perturbations. These are consistent with the expectation of the paradigm of inflation and the generic prediction of the simplest realization of inflationary scenario in the early universe. Further, gravitational instability is the established mechanism for structure formation from these initial perturbations. The signature of primordial perturbations observed as the CMB anisotropy and polarization is the most compelling evidence for new, possibly fundamental, physics in the early universe. The community is now looking beyond the estimation of parameters of a working `standard' model of cosmology for subtle, characteristic signatures from early universe physics.