Automorphic scalar fields in two-dimensional de Sitter space

Atsushi Higuchi, Lasse Schmieding, David Serrano Blanco

Research output: Contribution to journalArticlepeer-review


We study non-interacting automorphic quantum scalar fields with positive
mass in two-dimensional de Sitter space. We find that there are no Hadamard states which are de Sitter invariant except in the periodic case, extending the result of Epstein and Moschella for the anti-periodic case. We construct the two-point Wightman functions for the non-Hadamard de Sitter-invariant states by exploiting the fact that they are functions of the geodesic distance between the two points satisfying an ordinary differential equation. We then examine a certain Hadamard state, which is not de Sitter invariant, and show that it is approximately a thermal state with the Gibbons-Hawking temperature when restricted to a static region of the spacetime.
Original languageEnglish
Article number015009
Number of pages29
JournalClassical and Quantum Gravity
Publication statusPublished - 13 Dec 2022

Bibliographical note

© 2022 The Author(s)

Cite this