2003/06/24 by David H. Lyth, David H Lyth, David Wands · 4 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Computer science #Conserved quantity #Cosmological perturbation theory #Cosmology #Cosmology and Gravitation Theories #Curvature #Galaxies: Formation, Evolution, Phenomena #Geometry #Homogeneous #Mathematical physics #Mathematics #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Quantum mechanics #Slicing #Spacetime #Statistical physics #Theoretical physics #Universe #astro-ph #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.68.103515
published as Phys.Rev.D68:103515,2003 · 21 pages, latex with revtex, no figures
arxiv created 2003/06/24 · openalex publication_date 2003/11/25 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A conserved cosmological perturbation is associated with each quantity whose local evolution is determined entirely by the local expansion of the Universe. It may be defined as the appropriately normalized perturbation of the quantity, defined using a slicing of spacetime such that the expansion between slices is spatially homogeneous. To first order, on superhorizon scales, the slicing with unperturbed intrinsic curvature has this property. A general construction is given for conserved quantities, yielding the curvature perturbation \ensuremathζ as well as other more recently considered conserved perturbations. The construction may be extended to higher orders in perturbation theory and even into the non-perturbative regime.