### Abstract

We investigate the cosmology of a recently proposed deformation of Einstein gravity, emerging from quantum gravity heuristics. The theory is constructed to have de Sitter space as a vacuum solution, and thus to be relevant to the accelerating universe. However, this solution turns out to be unstable, and the true phase space of cosmological solutions is significantly more complex, displaying two late-time power-law attractors-one accelerating and the other dramatically decelerating. It is also shown that nonaccelerating cosmologies sit on a separatrix between the two basins of attraction of these attractors. Hence it is impossible to pass from a decelerating cosmology to an accelerating one, as required in standard cosmology for consistency with nucleosynthesis and structure formation and compatibility with the data inferred from supernovae Ia. We point out that alternative models of the early universe, such as the one investigated here might provide possible ways to circumvent these requirements.

Original language | English (US) |
---|---|

Article number | 043504 |

Pages (from-to) | 1-6 |

Number of pages | 6 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 72 |

Issue number | 4 |

DOIs | |

State | Published - Aug 15 2005 |

Externally published | Yes |

### Fingerprint

### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics

### Cite this

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*72*(4), 1-6. [043504]. https://doi.org/10.1103/PhysRevD.72.043504

**Cosmological constraints on a classical limit of quantum gravity.** / Easson, Damien; Schuller, Frederic P.; Trodden, Mark; Wohlfarth, Mattias N R.

Research output: Contribution to journal › Article

*Physical Review D - Particles, Fields, Gravitation and Cosmology*, vol. 72, no. 4, 043504, pp. 1-6. https://doi.org/10.1103/PhysRevD.72.043504

}

TY - JOUR

T1 - Cosmological constraints on a classical limit of quantum gravity

AU - Easson, Damien

AU - Schuller, Frederic P.

AU - Trodden, Mark

AU - Wohlfarth, Mattias N R

PY - 2005/8/15

Y1 - 2005/8/15

N2 - We investigate the cosmology of a recently proposed deformation of Einstein gravity, emerging from quantum gravity heuristics. The theory is constructed to have de Sitter space as a vacuum solution, and thus to be relevant to the accelerating universe. However, this solution turns out to be unstable, and the true phase space of cosmological solutions is significantly more complex, displaying two late-time power-law attractors-one accelerating and the other dramatically decelerating. It is also shown that nonaccelerating cosmologies sit on a separatrix between the two basins of attraction of these attractors. Hence it is impossible to pass from a decelerating cosmology to an accelerating one, as required in standard cosmology for consistency with nucleosynthesis and structure formation and compatibility with the data inferred from supernovae Ia. We point out that alternative models of the early universe, such as the one investigated here might provide possible ways to circumvent these requirements.

AB - We investigate the cosmology of a recently proposed deformation of Einstein gravity, emerging from quantum gravity heuristics. The theory is constructed to have de Sitter space as a vacuum solution, and thus to be relevant to the accelerating universe. However, this solution turns out to be unstable, and the true phase space of cosmological solutions is significantly more complex, displaying two late-time power-law attractors-one accelerating and the other dramatically decelerating. It is also shown that nonaccelerating cosmologies sit on a separatrix between the two basins of attraction of these attractors. Hence it is impossible to pass from a decelerating cosmology to an accelerating one, as required in standard cosmology for consistency with nucleosynthesis and structure formation and compatibility with the data inferred from supernovae Ia. We point out that alternative models of the early universe, such as the one investigated here might provide possible ways to circumvent these requirements.

UR - http://www.scopus.com/inward/record.url?scp=33749158545&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749158545&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.72.043504

DO - 10.1103/PhysRevD.72.043504

M3 - Article

AN - SCOPUS:33749158545

VL - 72

SP - 1

EP - 6

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 1550-7998

IS - 4

M1 - 043504

ER -