### Abstract

Reheating is a transition era after the end of inflation, during which the inflaton is converted into the particles that populate the Universe at later times. No direct cosmological observables are normally traceable to this period of reheating. Indirect bounds can however be derived. One possibility is to consider cosmological evolution for observable CMB scales from the time of Hubble crossing to the present time. Depending upon the model, the duration and final temperature after reheating, as well as its equation of state, may be directly linked to inflationary observables. For single-field inflationary models, if we approximate reheating by a constant equation of state, one can derive relations between the reheating duration (or final temperature), its equation of state parameter, and the scalar power spectrum amplitude and spectral index. While this is a simple approximation, by restricting the equation of state to lie within a broad physically allowed range, one can in turn bracket an allowed range of n<inf>s</inf> and r for these models. The added constraints can help break degeneracies between inflation models that otherwise overlap in their predictions for n<inf>s</inf> and r.

Original language | English (US) |
---|---|

Article number | 047 |

Journal | Journal of Cosmology and Astroparticle Physics |

Volume | 2015 |

Issue number | 4 |

DOIs | |

State | Published - Apr 28 2015 |

### Fingerprint

### Keywords

- cosmological parameters from CMBR
- ination
- physics of the early universe

### ASJC Scopus subject areas

- Astronomy and Astrophysics

### Cite this

*Journal of Cosmology and Astroparticle Physics*,

*2015*(4), [047]. https://doi.org/10.1088/1475-7516/2015/04/047

**Reheating predictions in single field inflation.** / Cook, Jessica L.; Dimastrogiovanni, Emanuela; Easson, Damien; Krauss, Lawrence.

Research output: Contribution to journal › Article

*Journal of Cosmology and Astroparticle Physics*, vol. 2015, no. 4, 047. https://doi.org/10.1088/1475-7516/2015/04/047

}

TY - JOUR

T1 - Reheating predictions in single field inflation

AU - Cook, Jessica L.

AU - Dimastrogiovanni, Emanuela

AU - Easson, Damien

AU - Krauss, Lawrence

PY - 2015/4/28

Y1 - 2015/4/28

N2 - Reheating is a transition era after the end of inflation, during which the inflaton is converted into the particles that populate the Universe at later times. No direct cosmological observables are normally traceable to this period of reheating. Indirect bounds can however be derived. One possibility is to consider cosmological evolution for observable CMB scales from the time of Hubble crossing to the present time. Depending upon the model, the duration and final temperature after reheating, as well as its equation of state, may be directly linked to inflationary observables. For single-field inflationary models, if we approximate reheating by a constant equation of state, one can derive relations between the reheating duration (or final temperature), its equation of state parameter, and the scalar power spectrum amplitude and spectral index. While this is a simple approximation, by restricting the equation of state to lie within a broad physically allowed range, one can in turn bracket an allowed range of ns and r for these models. The added constraints can help break degeneracies between inflation models that otherwise overlap in their predictions for ns and r.

AB - Reheating is a transition era after the end of inflation, during which the inflaton is converted into the particles that populate the Universe at later times. No direct cosmological observables are normally traceable to this period of reheating. Indirect bounds can however be derived. One possibility is to consider cosmological evolution for observable CMB scales from the time of Hubble crossing to the present time. Depending upon the model, the duration and final temperature after reheating, as well as its equation of state, may be directly linked to inflationary observables. For single-field inflationary models, if we approximate reheating by a constant equation of state, one can derive relations between the reheating duration (or final temperature), its equation of state parameter, and the scalar power spectrum amplitude and spectral index. While this is a simple approximation, by restricting the equation of state to lie within a broad physically allowed range, one can in turn bracket an allowed range of ns and r for these models. The added constraints can help break degeneracies between inflation models that otherwise overlap in their predictions for ns and r.

KW - cosmological parameters from CMBR

KW - ination

KW - physics of the early universe

UR - http://www.scopus.com/inward/record.url?scp=84928725207&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84928725207&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2015/04/047

DO - 10.1088/1475-7516/2015/04/047

M3 - Article

AN - SCOPUS:84928725207

VL - 2015

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 4

M1 - 047

ER -