# A Plausible Model of Inflation Driven by Strong Gravitational Wave Turbulence

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## Abstract

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## 1. Introduction

## 2. Friedmann Equations

## 3. Metric Cascades in GW Turbulence

## 4. Condensate and Inflation

## 5. Fossil Spectrum and CMB

## 6. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## Appendix A. Universe Expansion Driven by Nonlinear Gravitational Wave Interactions

## References

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1. | One should not be confused with the reference to quantum mechanics, which is made purely for a simple illustration of the relation between the energy and the wave action spectra. The system we are considering is purely classical, in a sense that the occupation numbers at all the momentum states are large. It would be possible to extend our consideration to the cases of small or moderate occupation numbers via writing a quantum kinetic equation based on, e.g., the Fermi golden rule. However, these cases can only be relevant to the direct cascade at very high k which is beyond the scope of the present paper. |

**Figure 1.**1D metric spectrum ${\widehat{H}}_{k}$ produced by an injection of wave action and energy fluxes at wavenumber ${k}_{i}$. The weak GW turbulence regime is localized in the interval ${k}_{s}<k\ll {k}_{P}$, where ${k}_{P}$ is the Planck wavenumber and ${k}_{s}$ determines the wavenumber below which GW turbulence is strong. In this scenario, the inverse cascade leads to the formation of a condensate at $k=0$. The growth of the condensate corresponds to an increase of the cosmic scale factor.

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**MDPI and ACS Style**

Galtier, S.; Laurie, J.; Nazarenko, S.V.
A Plausible Model of Inflation Driven by Strong Gravitational Wave Turbulence. *Universe* **2020**, *6*, 98.
https://doi.org/10.3390/universe6070098

**AMA Style**

Galtier S, Laurie J, Nazarenko SV.
A Plausible Model of Inflation Driven by Strong Gravitational Wave Turbulence. *Universe*. 2020; 6(7):98.
https://doi.org/10.3390/universe6070098

**Chicago/Turabian Style**

Galtier, Sébastien, Jason Laurie, and Sergey V. Nazarenko.
2020. "A Plausible Model of Inflation Driven by Strong Gravitational Wave Turbulence" *Universe* 6, no. 7: 98.
https://doi.org/10.3390/universe6070098