2020/05/22 by Lars H. Heyen, Lars Helge Heyen, Stefan Floerchinger
Mathematics · Physics and Astronomy · #Classical field theory #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Field (mathematics) #General relativity #Geometry #Limit (mathematics) #Mathematical analysis #Mathematical physics #Mathematics #Particle physics theoretical and experimental studies #Physics #Quantum electrodynamics #Scalar (mathematics) #Scalar field #Scalar theories of gravitation #Theoretical physics #hep-ph
paper · pdf · doi:10.1103/physrevd.102.036024
published as Phys. Rev. D 102, 036024 (2020)
arxiv created 2020/05/22 · openalex publication_date 2020/08/31 · arxiv updated 2020/09/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
The existing transformation from a relativistic real scalar field to a complex nonrelativistic scalar field by Namjoo, Guth, and Kaiser is generalized from Minkowski space to a more general background metric. In that case the transformation is not purely algebraic any more but determined by a differential equation. We apply the generalized transformation to a real scalar with \ensuremathφ4 interaction on an Friedmann-Lema\\itre-Robertson-Walker cosmologically expanding background and calculate the resulting nonrelativistic action up to second order in small parameters. We also show that the transformation can be interpreted as a Bogoliubov transformation between relativistic and nonrelativistic creation and annihilation operators and comment on emerging symmetries in the nonrelativistic theory.