# Can CMB data constrain the inflationary field range?

## Abstract

We study to what extent the spectral index n{sub s} and the tensor-to-scalar ratio r determine the field excursion Δφ during inflation. We analyse the possible degeneracy of Δ φ by comparing three broad classes of inflationary models, with different dependence on the number of e-foldings N, to benchmark models of chaotic inflation with monomial potentials. The classes discussed cover a large set of inflationary single field models. We find that the field range is not uniquely determined for any value of (n{sub s}, r); one can have the same predictions as chaotic inflation and a very different Δ φ. Intriguingly, we find that the field range cannot exceed an upper bound that appears in different classes of models. Finally, Δ φ can even become sub-Planckian, but this requires to go beyond the single-field slow-roll paradigm.

- Authors:

- Instituto de Física Teórica IFT-UAM-CSIC, Universidad Autónoma de Madrid, C/ Nicolás Cabrera 13-15, Cantoblanco, 28049 Madrid (Spain)
- Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

- Publication Date:

- OSTI Identifier:
- 22375901

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 09; Other Information: Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 97 MATHEMATICAL METHODS AND COMPUTING; BENCHMARKS; CHAOS THEORY; COSMOLOGICAL INFLATION; DATA; TENSORS

### Citation Formats

```
Garcia-Bellido, Juan, Roest, Diederik, Scalisi, Marco, and Zavala, Ivonne, E-mail: juan.garciabellido@uam.es, E-mail: d.roest@rug.nl, E-mail: m.scalisi@rug.nl, E-mail: e.i.zavala@rug.nl.
```*Can CMB data constrain the inflationary field range?*. United States: N. p., 2014.
Web. doi:10.1088/1475-7516/2014/09/006.

```
Garcia-Bellido, Juan, Roest, Diederik, Scalisi, Marco, & Zavala, Ivonne, E-mail: juan.garciabellido@uam.es, E-mail: d.roest@rug.nl, E-mail: m.scalisi@rug.nl, E-mail: e.i.zavala@rug.nl.
```*Can CMB data constrain the inflationary field range?*. United States. doi:10.1088/1475-7516/2014/09/006.

```
Garcia-Bellido, Juan, Roest, Diederik, Scalisi, Marco, and Zavala, Ivonne, E-mail: juan.garciabellido@uam.es, E-mail: d.roest@rug.nl, E-mail: m.scalisi@rug.nl, E-mail: e.i.zavala@rug.nl. Mon .
"Can CMB data constrain the inflationary field range?". United States.
doi:10.1088/1475-7516/2014/09/006.
```

```
@article{osti_22375901,
```

title = {Can CMB data constrain the inflationary field range?},

author = {Garcia-Bellido, Juan and Roest, Diederik and Scalisi, Marco and Zavala, Ivonne, E-mail: juan.garciabellido@uam.es, E-mail: d.roest@rug.nl, E-mail: m.scalisi@rug.nl, E-mail: e.i.zavala@rug.nl},

abstractNote = {We study to what extent the spectral index n{sub s} and the tensor-to-scalar ratio r determine the field excursion Δφ during inflation. We analyse the possible degeneracy of Δ φ by comparing three broad classes of inflationary models, with different dependence on the number of e-foldings N, to benchmark models of chaotic inflation with monomial potentials. The classes discussed cover a large set of inflationary single field models. We find that the field range is not uniquely determined for any value of (n{sub s}, r); one can have the same predictions as chaotic inflation and a very different Δ φ. Intriguingly, we find that the field range cannot exceed an upper bound that appears in different classes of models. Finally, Δ φ can even become sub-Planckian, but this requires to go beyond the single-field slow-roll paradigm.},

doi = {10.1088/1475-7516/2014/09/006},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 09,

volume = 2014,

place = {United States},

year = {Mon Sep 01 00:00:00 EDT 2014},

month = {Mon Sep 01 00:00:00 EDT 2014}

}