# Radiative corrections from heavy fast-roll fields during inflation

## Abstract

We investigate radiative corrections to the inflaton potential from heavy fields undergoing a fast-roll phase transition. We find that a logarithmic one-loop correction to the inflaton potential involving this field can induce a temporary running of the spectral index. The induced running can be a short burst of strong running, which may be related to the observed anomalies on large scales in the cosmic microwave spectrum, or extend over many e-folds, sustaining an effectively constant running to be searched for in the future. We implement this in a general class of models, where effects are mediated through a heavy messenger field sitting in its minimum. Interestingly, within the present framework it is a generic outcome that a large running implies a small field model with a vanishing tensor-to-scalar ratio, circumventing the normal expectation that small field models typically lead to an unobservably small running of the spectral index. An observable level of tensor modes can also be accommodated, but, surprisingly, this requires running to be induced by a curvaton. If upcoming observations are consistent with a small tensor-to-scalar ratio as predicted by small field models of inflation, then the present study serves as an explicit example contrary to the generalmore »

- Authors:

- CP"3-Origins, Center for Cosmology and Particle Physics Phenomenology,University of Southern Denmark,Campusvej 55, 5230 Odense M (Denmark)

- Publication Date:

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

- OSTI Identifier:
- 22454557

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 06; Other Information: PUBLISHER-ID: JCAP06(2015)016; OAI: oai:repo.scoap3.org:10623; 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; COSMOLOGICAL INFLATION; MICROWAVE SPECTRA; PHASE TRANSFORMATIONS; POTENTIALS; RADIATIVE CORRECTIONS; SCALAR FIELDS; TENSOR FIELDS; UNIVERSE

### Citation Formats

```
Jain, Rajeev Kumar, Sandora, McCullen, and Sloth, Martin S.
```*Radiative corrections from heavy fast-roll fields during inflation*. United States: N. p., 2015.
Web. doi:10.1088/1475-7516/2015/06/016.

```
Jain, Rajeev Kumar, Sandora, McCullen, & Sloth, Martin S.
```*Radiative corrections from heavy fast-roll fields during inflation*. United States. doi:10.1088/1475-7516/2015/06/016.

```
Jain, Rajeev Kumar, Sandora, McCullen, and Sloth, Martin S. Tue .
"Radiative corrections from heavy fast-roll fields during inflation". United States.
doi:10.1088/1475-7516/2015/06/016.
```

```
@article{osti_22454557,
```

title = {Radiative corrections from heavy fast-roll fields during inflation},

author = {Jain, Rajeev Kumar and Sandora, McCullen and Sloth, Martin S.},

abstractNote = {We investigate radiative corrections to the inflaton potential from heavy fields undergoing a fast-roll phase transition. We find that a logarithmic one-loop correction to the inflaton potential involving this field can induce a temporary running of the spectral index. The induced running can be a short burst of strong running, which may be related to the observed anomalies on large scales in the cosmic microwave spectrum, or extend over many e-folds, sustaining an effectively constant running to be searched for in the future. We implement this in a general class of models, where effects are mediated through a heavy messenger field sitting in its minimum. Interestingly, within the present framework it is a generic outcome that a large running implies a small field model with a vanishing tensor-to-scalar ratio, circumventing the normal expectation that small field models typically lead to an unobservably small running of the spectral index. An observable level of tensor modes can also be accommodated, but, surprisingly, this requires running to be induced by a curvaton. If upcoming observations are consistent with a small tensor-to-scalar ratio as predicted by small field models of inflation, then the present study serves as an explicit example contrary to the general expectation that the running will be unobservable.},

doi = {10.1088/1475-7516/2015/06/016},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 06,

volume = 2015,

place = {United States},

year = {Tue Jun 09 00:00:00 EDT 2015},

month = {Tue Jun 09 00:00:00 EDT 2015}

}