\documentclass[12pt]{article}
\usepackage{amsmath,amssymb,amsfonts}
\begin{document}
The celebrated Weinberg theorem in cosmological perturbat
ion theory states that there always exist two adiabatic scalar modes in which the comoving curvature pertur-bation is conserved on super-horizon scales. In particular when the perturbations are generated from a single source, such as in single field models of inflation, both of the two allowed independent solutions are adiabatic and conserved on super-horizon scales.There are few known examples in literature which violate this theorem. We revisit the theorem and specify the loopholes in some technical assumptions which violate the the-orem in models of non-attractor inflation, fluid inflation, solid inflation and in the model
of pseudo conformal universe
\end{document}