A note on the (non-)conservation of curvature perturbation
arXiv:2208.07568 · doi:10.1016/j.cjph.2023.01.005
Abstract
In this note, we compare two different definitions for the cosmological perturbation which is conserved on large scales, and study their non-conservation on small scales. We derive an equation for the time evolution of the curvature perturbation on a uniform density slice through a calculation solely in longitudinal (conformal-Newtonian) gauge. The result is concise and compatible with that obtained via local conservation of energy-momentum tensor.
9 pages, version to be published in the Chinese Journal of Physics