Abstract
The physical interpretation of perturbations of homogeneous, isotropic cosmological models in the early Universe, when the perturbation is larger than the particle horizon, is clarified by defining a complete set of gauge-invariant variables. The linearized perturbation equations written in these variables are simpler than the usual versions, and easily accommodate an arbitrary background equation of state, entropy perturbations, and anisotropic pressure perturbations. Particular attention is paid to how a scalar (density) perturbation might be generated by stress perturbations at very early times, when the non-gauge-invariant perturbation in the density itself is ill-defined. The amplitude of the fractional energy density perturbation at the particle horizon cannot be larger, in order of magnitude, than the maximum ratio of the stress perturbation to the background energy density at any earlier time, unless the perturbation is inherent in the initial singularity.
Keywords
PhysicsPerturbation (astronomy)Cosmological perturbation theoryClassical mechanicsIsotropyMathematical physicsAmplitudeInvariant (physics)Quantum mechanicsCosmology
Affiliated Institutions
Related Publications
Spontaneous creation of almost scale-free density perturbations in an inflationary universe
The creation and evolution of energy-density perturbations are analyzed for the "new inflationary universe" scenario proposed by Linde, and Albrecht and Steinhardt. According to...
Signatures of relativistic neutrinos in CMB anisotropy and matter clustering
We present a detailed analytical study of ultra-relativistic neutrinos in cosmological perturbation theory and of the observable signatures of inhomogeneities in the cosmic neut...
<i>Planck</i> 2018 results
We present cosmological parameter results from the final full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the t...
Three‐Year<i>Wilkinson Microwave Anisotropy Probe</i>(<i>WMAP</i>) Observations: Implications for Cosmology
A simple cosmological model with only six parameters (matter density,mh 2, baryon density,bh 2, Hubble con-stant, H0, amplitude of fluctuations, 8, optical depth, , and a slope ...
Correlated Perturbations from Inflation and the Cosmic Microwave Background
We compare the latest cosmic microwave background data with theoretical predictions including correlated adiabatic and cold dark matter (CDM) isocurvature perturbations with a s...
Publication Info
- Year
- 1980
- Type
- article
- Volume
- 22
- Issue
- 8
- Pages
- 1882-1905
- Citations
- 2237
- Access
- Closed
External Links
Social Impact
Altmetric
PlumX Metrics
Social media, news, blog, policy document mentions
Citation Metrics
2237
OpenAlex
Cite This
J. Bardeen
(1980).
Gauge-invariant cosmological perturbations.
Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields
, 22
(8)
, 1882-1905.
https://doi.org/10.1103/physrevd.22.1882
Identifiers
- DOI
- 10.1103/physrevd.22.1882