# Conservation of nonlinear curvature perturbations on super-Hubble scales

## Abstract

We consider general, non-linear curvature perturbations on scales greater than the Hubble horizon scale by invoking an expansion in spatial gradients, the so-called gradient expansion. After reviewing the basic properties of the gradient expansion, we derive the conservation law for non-linear curvature perturbations for an isentropic fluid. We also define the gauge-invariant curvature perturbation under a finite shift of time-slicing, and derive the non-linear genralization of the {delta}N formalism. The results obtained are straight-forward generalisations of those already proven in linear perturbation theory, and the equations are simple, resembling closely the first-order equations.

- Authors:

- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

- Publication Date:

- OSTI Identifier:
- 20729223

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: AIP Conference Proceedings; Journal Volume: 805; Journal Issue: 1; Conference: PASCOS 2005: 11. international symposium on particles, strings, and cosmology, Gyeongju (Korea, Republic of), 30 May - 4 Jun 2005; Other Information: DOI: 10.1063/1.2149682; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CONSERVATION LAWS; COSMOLOGY; DISTURBANCES; EXPANSION; FIELD EQUATIONS; GAUGE INVARIANCE; NONLINEAR PROBLEMS; PERTURBATION THEORY; QUANTUM FIELD THEORY

### Citation Formats

```
Sasaki, Misao.
```*Conservation of nonlinear curvature perturbations on super-Hubble scales*. United States: N. p., 2005.
Web. doi:10.1063/1.2149682.

```
Sasaki, Misao.
```*Conservation of nonlinear curvature perturbations on super-Hubble scales*. United States. doi:10.1063/1.2149682.

```
Sasaki, Misao. Fri .
"Conservation of nonlinear curvature perturbations on super-Hubble scales". United States.
doi:10.1063/1.2149682.
```

```
@article{osti_20729223,
```

title = {Conservation of nonlinear curvature perturbations on super-Hubble scales},

author = {Sasaki, Misao},

abstractNote = {We consider general, non-linear curvature perturbations on scales greater than the Hubble horizon scale by invoking an expansion in spatial gradients, the so-called gradient expansion. After reviewing the basic properties of the gradient expansion, we derive the conservation law for non-linear curvature perturbations for an isentropic fluid. We also define the gauge-invariant curvature perturbation under a finite shift of time-slicing, and derive the non-linear genralization of the {delta}N formalism. The results obtained are straight-forward generalisations of those already proven in linear perturbation theory, and the equations are simple, resembling closely the first-order equations.},

doi = {10.1063/1.2149682},

journal = {AIP Conference Proceedings},

number = 1,

volume = 805,

place = {United States},

year = {Fri Dec 02 00:00:00 EST 2005},

month = {Fri Dec 02 00:00:00 EST 2005}

}

DOI: 10.1063/1.2149682

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