# More on loops in reheating: non-gaussianities and tensor power spectrum

## Abstract

We consider the single field chaotic m{sup 2}ϕ{sup 2} inflationary model with a period of preheating, where the inflaton decays to another scalar field χ in the parametric resonance regime. In a recent work, one of us has shown that the χ modes circulating in the loops during preheating notably modify the correlation function. We first rederive this result using a different gauge condition hence reconfirm that superhorizon ζ modes are affected by the loops in preheating. Further, we examine how χ loops give rise to non-gaussianity and affect the tensor perturbations. For that, all cubic and some higher order interactions involving two χ fields are determined and their contribution to the non-gaussianity parameter f{sub NL} and the tensor power spectrum are calculated at one loop. Our estimates for these corrections show that while a large amount of non-gaussianity can be produced during reheating, the tensor power spectrum receive moderate corrections. We observe that the loop quantum effects increase with more χ fields circulating in the loops indicating that the perturbation theory might be broken down. These findings demonstrate that the loop corrections during reheating are significant and they must be taken into account for precision inflationary cosmology.

- Authors:

- Bogaziçi University, Department of Physics, Bebek, İstanbul, 34342 (Turkey)

- Publication Date:

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

- OSTI Identifier:
- 22454497

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2014)022; OAI: oai:repo.scoap3.org:2785; 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; ACCURACY; CORRECTIONS; CORRELATION FUNCTIONS; COSMOLOGICAL INFLATION; COSMOLOGY; INTERACTIONS; PERTURBATION THEORY; RESONANCE; SCALAR FIELDS; SPECTRA; TENSORS

### Citation Formats

```
Katırcı, Nihan, Kaya, Ali, and Tarman, Merve.
```*More on loops in reheating: non-gaussianities and tensor power spectrum*. United States: N. p., 2014.
Web. doi:10.1088/1475-7516/2014/06/022.

```
Katırcı, Nihan, Kaya, Ali, & Tarman, Merve.
```*More on loops in reheating: non-gaussianities and tensor power spectrum*. United States. doi:10.1088/1475-7516/2014/06/022.

```
Katırcı, Nihan, Kaya, Ali, and Tarman, Merve. Wed .
"More on loops in reheating: non-gaussianities and tensor power spectrum". United States.
doi:10.1088/1475-7516/2014/06/022.
```

```
@article{osti_22454497,
```

title = {More on loops in reheating: non-gaussianities and tensor power spectrum},

author = {Katırcı, Nihan and Kaya, Ali and Tarman, Merve},

abstractNote = {We consider the single field chaotic m{sup 2}ϕ{sup 2} inflationary model with a period of preheating, where the inflaton decays to another scalar field χ in the parametric resonance regime. In a recent work, one of us has shown that the χ modes circulating in the loops during preheating notably modify the correlation function. We first rederive this result using a different gauge condition hence reconfirm that superhorizon ζ modes are affected by the loops in preheating. Further, we examine how χ loops give rise to non-gaussianity and affect the tensor perturbations. For that, all cubic and some higher order interactions involving two χ fields are determined and their contribution to the non-gaussianity parameter f{sub NL} and the tensor power spectrum are calculated at one loop. Our estimates for these corrections show that while a large amount of non-gaussianity can be produced during reheating, the tensor power spectrum receive moderate corrections. We observe that the loop quantum effects increase with more χ fields circulating in the loops indicating that the perturbation theory might be broken down. These findings demonstrate that the loop corrections during reheating are significant and they must be taken into account for precision inflationary cosmology.},

doi = {10.1088/1475-7516/2014/06/022},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 06,

volume = 2014,

place = {United States},

year = {Wed Jun 11 00:00:00 EDT 2014},

month = {Wed Jun 11 00:00:00 EDT 2014}

}