J. Garriga, PAIR PRODUCTION BY AN ELECTRIC-FIELD IN (1-DIMENSIONAL DESITTER SPACE(1)), Physical review. D. Particles and fields, 49(12), 1994, pp. 6343-6346
We use the method of Bogolubov transformations to compute the rate of
pair production by an electric field in (1+1)-dimensional de Sitter sp
ace. The results are in agreement with those obtained previously using
the instanton methods. This is true even when the size of the instant
on is comparable to the size of the de Sitter horizon.