# Energy-momentum tensor of bouncing gravitons

## Abstract

In models of the Universe with extra dimensions gravity propagates in the whole space-time. Graviton production by matter on the brane is significant in the early hot Universe. In a model of 3-brane with matter embedded in 5D space-time conditions for gravitons emitted from the brane to the bulk to return back to the brane are found. For a given 5-momentum of graviton falling back to the brane the interval between the times of emission and return to the brane is calculated. A method to calculate contribution to the energy-momentum tensor from multiple graviton bouncings is developed. Explicit expressions for contributions to the energy-momentum tensor of gravitons which have made one, two and three bounces are obtained and their magnitudes are numerically calculated. These expressions are used to solve the evolution equation for dark radiation. A relation connecting reheating temperature and the scale of extra dimension is obtained. For the reheating temperature T{sub R}∼10{sup 6} GeV we estimate the scale of extra dimension μ to be of order 10{sup −9} GeV (μ{sup −1}∼10{sup −5} cm)

- Authors:

- Skobeltsyn Institute of Nuclear Physics, Moscow State University,Moscow 119992 (Russian Federation)

- Publication Date:

- Sponsoring Org.:
- SCOAP3, CERN, Geneva (Switzerland)

- OSTI Identifier:
- 22454569

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 07; Other Information: PUBLISHER-ID: JCAP07(2015)021; OAI: oai:repo.scoap3.org:11077; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BRANES; ENERGY-MOMENTUM TENSOR; GEV RANGE; GRAVITATION; GRAVITONS; MATHEMATICAL EVOLUTION; SPACE-TIME; UNIVERSE

### Citation Formats

```
Iofa, Mikhail Z.
```*Energy-momentum tensor of bouncing gravitons*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/07/021.

```
Iofa, Mikhail Z.
```*Energy-momentum tensor of bouncing gravitons*. United States. doi:10.1088/1475-7516/2015/07/021.

```
Iofa, Mikhail Z. Tue .
"Energy-momentum tensor of bouncing gravitons". United States.
doi:10.1088/1475-7516/2015/07/021.
```

```
@article{osti_22454569,
```

title = {Energy-momentum tensor of bouncing gravitons},

author = {Iofa, Mikhail Z.},

abstractNote = {In models of the Universe with extra dimensions gravity propagates in the whole space-time. Graviton production by matter on the brane is significant in the early hot Universe. In a model of 3-brane with matter embedded in 5D space-time conditions for gravitons emitted from the brane to the bulk to return back to the brane are found. For a given 5-momentum of graviton falling back to the brane the interval between the times of emission and return to the brane is calculated. A method to calculate contribution to the energy-momentum tensor from multiple graviton bouncings is developed. Explicit expressions for contributions to the energy-momentum tensor of gravitons which have made one, two and three bounces are obtained and their magnitudes are numerically calculated. These expressions are used to solve the evolution equation for dark radiation. A relation connecting reheating temperature and the scale of extra dimension is obtained. For the reheating temperature T{sub R}∼10{sup 6} GeV we estimate the scale of extra dimension μ to be of order 10{sup −9} GeV (μ{sup −1}∼10{sup −5} cm)},

doi = {10.1088/1475-7516/2015/07/021},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 07,

volume = 2015,

place = {United States},

year = {Tue Jul 14 00:00:00 EDT 2015},

month = {Tue Jul 14 00:00:00 EDT 2015}

}