## Abstract

We demonstrate in examples that the covariant retarded Green's functions in electromagnetism and linearized gravity work as expected in de Sitter spacetime. We first clarify how retarded Green's functions should be used in spacetimes with spacelike past infinity such as de Sitter spacetime. In particular, we remind the reader of a general formula which gives the field for given initial data on a Cauchy surface and a given source (a charge or stress-energy tensor distribution) in its future. We then apply this formula to three examples: (i) electromagnetism in the future of a Cauchy surface in Minkowski spacetime, (ii) electromagnetism in de Sitter spacetime, and (iii) linearized gravity in de Sitter spacetime. In each example the field is reproduced correctly as predicted by the general argument. In the third example we construct a linearized gravitational field from two equal point masses located at the "North and South Poles" which is nonsingular on the cosmological horizon and satisfies a covariant gauge condition and show that this field is reproduced by the retarded Green's function with corresponding gauge parameters.

Original language | English |
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Article number | 084031 |

Number of pages | 17 |

Journal | Physical review d |

Volume | 78 |

Issue number | 8 |

DOIs | |

Publication status | Published - 24 Oct 2008 |

## Keywords

- ROBERTSON-WALKER UNIVERSES
- GRAVITON PROPAGATOR
- INFLATIONARY UNIVERSE
- DESITTER SPACETIME
- SYMMETRY-BREAKING
- PHASE-TRANSITION
- 2-POINT FUNCTION
- VACUUM
- INSTABILITY
- FLATNESS