# Phases of inflation

## Abstract

Motivated by the 4d effective field theories for closed string axions in Type II string compactifications with D-branes, we consider chiral gauge theories coupled to multiple axions. We discuss how well-known non-perturbative dynamical phenomena, such as gauge instantons, fermion confinement and Nambu-Jona-Lasinio interactions, give rise to non-trivial vacuum configurations in the IR. The fluctuations about the IR vacuum are captured by some remaining closed string axions and infladrons (scalar chiral condensate excitations), which acquire dynamical masses. By employing the full power of the effective field theory, we investigate the applicability of these IR theories as inflationary models (natural, monodromy, Starobinsky) and connect different types of inflationary scenarios to different phases of the non-Abelian gauge theory or the Nambu-Jona-Lasinio four-fermion couplings. The back-reaction of the infladrons flattens the axion potential in natural-like inflationary models, such that the tension with current CMB data with respect to the spectral index and the tensor-to-scalar ratio can be partially alleviated.

- Authors:

- Univ. of Wisconsin, Madison, WI (United States). Dept. of Physics
- Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Fisica Teorica

- Publication Date:

- Research Org.:
- Univ. of Wisconsin, Madison, WI (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC)

- OSTI Identifier:
- 1483399

- Grant/Contract Number:
- SC0017647

- Resource Type:
- Journal Article: Accepted Manuscript

- Journal Name:
- Journal of High Energy Physics (Online)

- Additional Journal Information:
- Journal Volume: 2018; Journal Issue: 10; Journal ID: ISSN 1029-8479

- Publisher:
- Springer Berlin

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTRONOMY AND ASTROPHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

### Citation Formats

```
Shiu, Gary, and Staessens, Wieland.
```*Phases of inflation*. United States: N. p., 2018.
Web. doi:10.1007/JHEP10(2018)085.

```
Shiu, Gary, & Staessens, Wieland.
```*Phases of inflation*. United States. doi:10.1007/JHEP10(2018)085.

```
Shiu, Gary, and Staessens, Wieland. Fri .
"Phases of inflation". United States. doi:10.1007/JHEP10(2018)085. https://www.osti.gov/servlets/purl/1483399.
```

```
@article{osti_1483399,
```

title = {Phases of inflation},

author = {Shiu, Gary and Staessens, Wieland},

abstractNote = {Motivated by the 4d effective field theories for closed string axions in Type II string compactifications with D-branes, we consider chiral gauge theories coupled to multiple axions. We discuss how well-known non-perturbative dynamical phenomena, such as gauge instantons, fermion confinement and Nambu-Jona-Lasinio interactions, give rise to non-trivial vacuum configurations in the IR. The fluctuations about the IR vacuum are captured by some remaining closed string axions and infladrons (scalar chiral condensate excitations), which acquire dynamical masses. By employing the full power of the effective field theory, we investigate the applicability of these IR theories as inflationary models (natural, monodromy, Starobinsky) and connect different types of inflationary scenarios to different phases of the non-Abelian gauge theory or the Nambu-Jona-Lasinio four-fermion couplings. The back-reaction of the infladrons flattens the axion potential in natural-like inflationary models, such that the tension with current CMB data with respect to the spectral index and the tensor-to-scalar ratio can be partially alleviated.},

doi = {10.1007/JHEP10(2018)085},

journal = {Journal of High Energy Physics (Online)},

issn = {1029-8479},

number = 10,

volume = 2018,

place = {United States},

year = {2018},

month = {10}

}