### Abstract

Extending the proof of the cosmic no-hair theorem for Bianchi models in power-law inflation, the authors prove a more general cosmic no-hair theorem for all 0<or= lambda < square root 2, where lambda is the coupling constant of an exponential potential of an inflaton phi , exp(- lambda kappa phi ). For any initially expanding Bianchi-type model except type IX, they find that the isotropic inflationary solution is the unique attractor and that anisotropies always enhance inflation. For Bianchi IX, this conclusion is also true, if the initial ratio of the vacuum energy Lambda _{eff} to the maximum 3-curvature ^{(3)}R_{max} is larger than 1/(3(1- lambda ^{2}/2)) and its time derivative is initially positive. It turns out that the sufficient condition for inflation in Bianchi type=IX spacetimes with cosmological constant Lambda , which is a special case of the theorem ( lambda =0) become less restrictive than Wald's one (1984). For type IX, they also show a recollapse theorem.

Original language | English |
---|---|

Article number | 008 |

Pages (from-to) | 703-734 |

Number of pages | 32 |

Journal | Classical and Quantum Gravity |

Volume | 10 |

Issue number | 4 |

DOIs | |

Publication status | Published - 1993 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Classical and Quantum Gravity*,

*10*(4), 703-734. [008]. https://doi.org/10.1088/0264-9381/10/4/008

**Cosmic no-hair theorem in homogeneous spacetimes. I. Bianchi models.** / Kitada, Y.; Maeda, Keiichi.

Research output: Contribution to journal › Article

*Classical and Quantum Gravity*, vol. 10, no. 4, 008, pp. 703-734. https://doi.org/10.1088/0264-9381/10/4/008

}

TY - JOUR

T1 - Cosmic no-hair theorem in homogeneous spacetimes. I. Bianchi models

AU - Kitada, Y.

AU - Maeda, Keiichi

PY - 1993

Y1 - 1993

N2 - Extending the proof of the cosmic no-hair theorem for Bianchi models in power-law inflation, the authors prove a more general cosmic no-hair theorem for all 0eff to the maximum 3-curvature (3)Rmax is larger than 1/(3(1- lambda 2/2)) and its time derivative is initially positive. It turns out that the sufficient condition for inflation in Bianchi type=IX spacetimes with cosmological constant Lambda , which is a special case of the theorem ( lambda =0) become less restrictive than Wald's one (1984). For type IX, they also show a recollapse theorem.

AB - Extending the proof of the cosmic no-hair theorem for Bianchi models in power-law inflation, the authors prove a more general cosmic no-hair theorem for all 0eff to the maximum 3-curvature (3)Rmax is larger than 1/(3(1- lambda 2/2)) and its time derivative is initially positive. It turns out that the sufficient condition for inflation in Bianchi type=IX spacetimes with cosmological constant Lambda , which is a special case of the theorem ( lambda =0) become less restrictive than Wald's one (1984). For type IX, they also show a recollapse theorem.

UR - http://www.scopus.com/inward/record.url?scp=21144483474&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=21144483474&partnerID=8YFLogxK

U2 - 10.1088/0264-9381/10/4/008

DO - 10.1088/0264-9381/10/4/008

M3 - Article

AN - SCOPUS:21144483474

VL - 10

SP - 703

EP - 734

JO - Classical and Quantum Gravity

JF - Classical and Quantum Gravity

SN - 0264-9381

IS - 4

M1 - 008

ER -