### Abstract

We study cosmological applications of extended vector–tensor theories, whose Lagrangians contain up to two derivatives with respect to metric and vector field. We derive background equations under the assumption of homogeneous and isotropic universe and study the nature of cosmological perturbations on top of the background. We found an example of healthy cosmological solutions in non-trivial degenerate theory of gravity for the first time, where those perturbations do not suffer from any instabilities, that is, ghost and gradient instabilities.

Original language | English |
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Pages (from-to) | 320-325 |

Number of pages | 6 |

Journal | Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 783 |

DOIs | |

Publication status | Published - 2018 Aug 10 |

Externally published | Yes |

### Fingerprint

### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

*Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics*,

*783*, 320-325. https://doi.org/10.1016/j.physletb.2018.07.009

**Stable cosmological solutions in degenerate theory of gravity.** / Kase, Ryotaro; Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke.

Research output: Contribution to journal › Article

*Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics*, vol. 783, pp. 320-325. https://doi.org/10.1016/j.physletb.2018.07.009

}

TY - JOUR

T1 - Stable cosmological solutions in degenerate theory of gravity

AU - Kase, Ryotaro

AU - Kimura, Rampei

AU - Naruko, Atsushi

AU - Yoshida, Daisuke

PY - 2018/8/10

Y1 - 2018/8/10

N2 - We study cosmological applications of extended vector–tensor theories, whose Lagrangians contain up to two derivatives with respect to metric and vector field. We derive background equations under the assumption of homogeneous and isotropic universe and study the nature of cosmological perturbations on top of the background. We found an example of healthy cosmological solutions in non-trivial degenerate theory of gravity for the first time, where those perturbations do not suffer from any instabilities, that is, ghost and gradient instabilities.

AB - We study cosmological applications of extended vector–tensor theories, whose Lagrangians contain up to two derivatives with respect to metric and vector field. We derive background equations under the assumption of homogeneous and isotropic universe and study the nature of cosmological perturbations on top of the background. We found an example of healthy cosmological solutions in non-trivial degenerate theory of gravity for the first time, where those perturbations do not suffer from any instabilities, that is, ghost and gradient instabilities.

UR - http://www.scopus.com/inward/record.url?scp=85051255380&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85051255380&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2018.07.009

DO - 10.1016/j.physletb.2018.07.009

M3 - Article

VL - 783

SP - 320

EP - 325

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

ER -