title: Infrared behavior and gauge artifacts in de Sitter spacetime: the photon field.
abstract: We study the infrared (long-distance) behavior of the free photon field in de Sitter spacetime. Using a two-parameter family of gauge-fixing terms, we show that the infrared (IR) behavior of the two-point function is highly gauge-dependent and ranges from vanishing to growing. This situation is in disagreement with its counterpart in flat spacetime, where the two-point function vanishes in the IR region for any choice of the gauge-fixing parameters. A criterion to isolate the physical part of the two-point function is given and is shown to lead to a well-behaved two-point function in the IR region.
authors.affiliation: Université Paris Diderot Paris 7, Laboratoire APC, Bâtiment Condorcet, Case 7020, 75205 Paris Cedex 13, France. ahmed.youssef@apc.univ-paris7.fr
authors.forename: A
authors.initials: A
authors.lastname: Youssef