# Cosmology for quadratic gravity in generalized Weyl geometry

## Abstract

A class of vector-tensor theories arises naturally in the framework of quadratic gravity in spacetimes with linear vector distortion. Requiring the absence of ghosts for the vector field imposes an interesting condition on the allowed connections with vector distortion: the resulting one-parameter family of connections generalises the usual Weyl geometry with polar torsion. The cosmology of this class of theories is studied, focusing on isotropic solutions wherein the vector field is dominated by the temporal component. De Sitter attractors are found and inhomogeneous perturbations around such backgrounds are analysed. In particular, further constraints on the models are imposed by excluding pathologies in the scalar, vector and tensor fluctuations. Various exact background solutions are presented, describing a constant and an evolving dark energy, a bounce and a self-tuning de Sitter phase. However, the latter two scenarios are not viable under a closer scrutiny.

- Authors:

- CPT, Aix Marseille Université, UMR 7332,13288 Marseille (France)
- Institute for Theoretical Studies, ETH Zurich,Clausiusstrasse 47, 8092 Zurich (Switzerland)
- Nordita, KTH Royal Institute of Technology and Stockholm University,Roslagstullsbacken 23, 10691 Stockholm (Sweden)

- Publication Date:

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

- OSTI Identifier:
- 22572068

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2016; Journal Issue: 04; Other Information: PUBLISHER-ID: JCAP04(2016)046; OAI: oai:repo.scoap3.org:15365; cc-by 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:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGY; DE SITTER GROUP; DE SITTER SPACE; EXACT SOLUTIONS; GEOMETRY; GRAVITATION; NONLUMINOUS MATTER; PERTURBATION THEORY; SPACE-TIME; VECTOR FIELDS; WEYL UNIFIED THEORY

### Citation Formats

```
Jiménez, Jose Beltrán, Heisenberg, Lavinia, and Koivisto, Tomi S.
```*Cosmology for quadratic gravity in generalized Weyl geometry*. United States: N. p., 2016.
Web. doi:10.1088/1475-7516/2016/04/046.

```
Jiménez, Jose Beltrán, Heisenberg, Lavinia, & Koivisto, Tomi S.
```*Cosmology for quadratic gravity in generalized Weyl geometry*. United States. doi:10.1088/1475-7516/2016/04/046.

```
Jiménez, Jose Beltrán, Heisenberg, Lavinia, and Koivisto, Tomi S. Tue .
"Cosmology for quadratic gravity in generalized Weyl geometry". United States.
doi:10.1088/1475-7516/2016/04/046.
```

```
@article{osti_22572068,
```

title = {Cosmology for quadratic gravity in generalized Weyl geometry},

author = {Jiménez, Jose Beltrán and Heisenberg, Lavinia and Koivisto, Tomi S.},

abstractNote = {A class of vector-tensor theories arises naturally in the framework of quadratic gravity in spacetimes with linear vector distortion. Requiring the absence of ghosts for the vector field imposes an interesting condition on the allowed connections with vector distortion: the resulting one-parameter family of connections generalises the usual Weyl geometry with polar torsion. The cosmology of this class of theories is studied, focusing on isotropic solutions wherein the vector field is dominated by the temporal component. De Sitter attractors are found and inhomogeneous perturbations around such backgrounds are analysed. In particular, further constraints on the models are imposed by excluding pathologies in the scalar, vector and tensor fluctuations. Various exact background solutions are presented, describing a constant and an evolving dark energy, a bounce and a self-tuning de Sitter phase. However, the latter two scenarios are not viable under a closer scrutiny.},

doi = {10.1088/1475-7516/2016/04/046},

journal = {Journal of Cosmology and Astroparticle Physics},

number = 04,

volume = 2016,

place = {United States},

year = {Tue Apr 26 00:00:00 EDT 2016},

month = {Tue Apr 26 00:00:00 EDT 2016}

}