Regular Article - Theoretical Physics
Massive scalar field in de Sitter spacetime: a two-loop calculation and a comparison with the stochastic approach
Dipartimento di Fisica e Astronomia, Università di Bologna and INFN, via Irnerio 46, 40126, Bologna, Italy
2 L. D. Landau Institute for Theoretical Physics, 119334, Moscow, Russia
3 Bogolyubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980, Dubna, Russia
4 Dipartimento di Fisica e Chimica, Università di L’Aquila, 67100, Coppito, L’Aquila, Italy
5 INFN, Laboratori Nazionali del Gran Sasso, 67010, Assergi, L’Aquila, Italy
Accepted: 5 April 2022
Published online: 20 April 2022
We examine long-wavelength correlation functions of massive scalar fields in de Sitter spacetime. For the theory with a quartic self-interaction, the two-point function is calculated up to two loops. Comparing our results with the Hartree–Fock approximation and with the stochastic approach shows that the former resums only the cactus type diagrams, whereas the latter contains the sunset diagram as well and produces the correct result. We also demonstrate that the long-wavelength expectation value of the commutator of two fields is equal to zero both for spacelike and timelike separated points.
© The Author(s) 2022
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