Beyond the Standard cosmological model with CMB

TL;DR

This paper reviews how CMB measurements have confirmed key aspects of the standard cosmological model and discusses ongoing efforts to detect subtle signals of new physics from the early universe.

Contribution

It highlights the importance of CMB anisotropy and polarization in confirming the standard model and explores future directions for detecting signatures of early universe physics.

Findings

CMB measurements support adiabatic, primordial perturbations

Gravitational instability explains structure formation

CMB provides evidence for physics beyond the standard model

Abstract

Measurements of CMB anisotropy and, more recently, polarization have played a very important role in cosmology. 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, adiabatic, primordial perturbations in a flat, statistically isotropic universe. 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. 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 parameter estimation of the `standard' model, for subtle, characteristic signatures of early universe physics.