What question did this study set out to answer?

To resolve ambiguities in interpreting superhorizon perturbations in the early Universe by constructing a complete framework of gauge-invariant variables.

October 15, 1980Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields

Gauge-invariant cosmological perturbations

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JBJ. BardeenUniversity of Washington

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Implication

Theoretical analysis reveals gauge-invariant dynamics of perturbations in early cosmological models, highlighting strict bounds on primordial density fluctuations.

Key Points

To resolve ambiguities in interpreting superhorizon perturbations in the early Universe by constructing a complete framework of gauge-invariant variables.
Formulated a complete set of gauge-invariant variables for linearized perturbations in homogeneous, isotropic cosmological spacetimes.
Derived simplified linear perturbation equations accommodating arbitrary background equations of state, entropy perturbations, and anisotropic pressure stresses.
Clarified the physical interpretation of perturbations that exceed the particle horizon, where standard coordinate-dependent density perturbations are ill-defined.
Demonstrated that the fractional energy density perturbation entering the horizon is bounded by the maximum earlier ratio of stress perturbations to background energy density, unless inherent to the initial singularity.

Cite This Study

J. Bardeen (1980) studied this question.

synapsesocial.com/papers/69daaab9aae38ff6ad835827 https://doi.org/10.1103/physrevd.22.1882

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Implication

Theoretical analysis reveals gauge-invariant dynamics of perturbations in early cosmological models, highlighting strict bounds on primordial density fluctuations.

Gauge-invariant cosmological perturbations

Discussion

Member takes

Implication

Key Points

Cite This Study

Gauge-invariant cosmological perturbations

Discussion

Member takes

Implication

Key Points

Cite This Study

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