# Starobinsky-type inflation from α{sup ′}-corrections

## Abstract

Working in the Large Volume Scenario (LVS) of IIB Calabi-Yau flux compactifications, we construct inflationary models from recently computed higher derivative (α{sup ′}){sup 3}-corrections. Inflation is driven by a Kähler modulus whose potential arises from the aforementioned corrections, while we use the inclusion of string loop effects just to ensure the existence of a graceful exit when necessary. The effective inflaton potential takes a Starobinsky-type form V=V{sub 0}(1−e{sup −νϕ}){sup 2}, where we obtain one set-up with ν=−1/√3 and one with ν=2/√3 corresponding to inflation occurring for increasing or decreasing ϕ respectively. The inflationary observables are thus in perfect agreement with PLANCK, while the two scenarios remain observationally distinguishable via slightly varying predictions for the tensor-to-scalar ratio r. Both set-ups yield r≃(2…7) ×10{sup −3}. They hence realise inflation with moderately large fields (Δϕ∼6 M{sub Pl}) without saturating the Lyth bound. Control over higher corrections relies in part on tuning underlying microscopic parameters, and in part on intrinsic suppressions. The intrinsic part of control arises as a leftover from an approximate effective shift symmetry at parametrically large volume.

- Authors:

- Deutsches Elektronen-Synchrotron DESY, Theory Group,22603 Hamburg (Germany)
- Departamento de Física Teórica and Instituto de Física Teórica UAM-CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain)

- Publication Date:

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

- OSTI Identifier:
- 22458422

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 01; Other Information: PUBLISHER-ID: JCAP01(2016)001; OAI: oai:repo.scoap3.org:13320; 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; SCALARS; STRING THEORY; SYMMETRY; TENSORS

### Citation Formats

```
Broy, Benedict J., Ciupke, David, Pedro, Francisco G., and Westphal, Alexander.
```*Starobinsky-type inflation from α{sup ′}-corrections*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/01/001.

```
Broy, Benedict J., Ciupke, David, Pedro, Francisco G., & Westphal, Alexander.
```*Starobinsky-type inflation from α{sup ′}-corrections*. United States. doi:10.1088/1475-7516/2016/01/001.

```
Broy, Benedict J., Ciupke, David, Pedro, Francisco G., and Westphal, Alexander. Mon .
"Starobinsky-type inflation from α{sup ′}-corrections". United States.
doi:10.1088/1475-7516/2016/01/001.
```

```
@article{osti_22458422,
```

title = {Starobinsky-type inflation from α{sup ′}-corrections},

author = {Broy, Benedict J. and Ciupke, David and Pedro, Francisco G. and Westphal, Alexander},

abstractNote = {Working in the Large Volume Scenario (LVS) of IIB Calabi-Yau flux compactifications, we construct inflationary models from recently computed higher derivative (α{sup ′}){sup 3}-corrections. Inflation is driven by a Kähler modulus whose potential arises from the aforementioned corrections, while we use the inclusion of string loop effects just to ensure the existence of a graceful exit when necessary. The effective inflaton potential takes a Starobinsky-type form V=V{sub 0}(1−e{sup −νϕ}){sup 2}, where we obtain one set-up with ν=−1/√3 and one with ν=2/√3 corresponding to inflation occurring for increasing or decreasing ϕ respectively. The inflationary observables are thus in perfect agreement with PLANCK, while the two scenarios remain observationally distinguishable via slightly varying predictions for the tensor-to-scalar ratio r. Both set-ups yield r≃(2…7) ×10{sup −3}. They hence realise inflation with moderately large fields (Δϕ∼6 M{sub Pl}) without saturating the Lyth bound. Control over higher corrections relies in part on tuning underlying microscopic parameters, and in part on intrinsic suppressions. The intrinsic part of control arises as a leftover from an approximate effective shift symmetry at parametrically large volume.},

doi = {10.1088/1475-7516/2016/01/001},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 01,

volume = 2016,

place = {United States},

year = {Mon Jan 04 00:00:00 EST 2016},

month = {Mon Jan 04 00:00:00 EST 2016}

}