https://doi.org/10.1140/epjc/s10052-026-15393-w
Regular Article - Theoretical Physics
Perturbative corrections to soft photon theorems for massless scalar QED in de Sitter spacetime
School of Physics, The University of Electronic Science and Technology of China, No. 2006, Xiyuan Avenue, West Hi-Tech Zone, 611731, Chengdu, Sichuan, People’s Republic of China
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Received:
3
December
2025
Accepted:
31
January
2026
Published online:
20
February
2026
Abstract
The perturbative corrections to soft photon theorems with massive scalars in de Sitter spacetime were computed in (Bhatkar and Jain in J High Energy Phys 2023:55, 2023). However, the massless limit of the scalar modes is ill-defined in their work. It therefore is ambiguous to take the massless limit of the soft factors. In this paper, we derive the massless scalar modes in d-dimensional de Sitter spacetime and use it to compute the perturbative corrections to the leading and sub-leading soft photon theorems. Our framework corresponds to tree level scattering of massless scalars followed by an emission of a soft photon in a compact region of the static patch of de Sitter. We show that our results are consistent with (Bhatkar and Jain in J High Energy Phys 2023:55, 2023) in the massless limit and we comment on the universality of our results.
© The Author(s) 2026
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