Lattice simulations of non-minimally coupled scalar fields in the Jordan frame

The presence of scalar fields with non-minimal gravitational interactions of the form $\xi |\phi|^2 R$ may have important implications for the physics of the early universe. We propose a procedure to solve the dynamics of non-minimally coupled scalar fields directly in the Jordan frame, where the no...

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Bibliographic Details
Main Author: Daniel G. Figueroa, Adrien Florio, Toby Opferkuch, and Ben A. Stefanek
Format: Article
Language:English
Published: SciPost 2023-09-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.15.3.077
Description
Summary:The presence of scalar fields with non-minimal gravitational interactions of the form $\xi |\phi|^2 R$ may have important implications for the physics of the early universe. We propose a procedure to solve the dynamics of non-minimally coupled scalar fields directly in the Jordan frame, where the non-minimal couplings are maintained explicitly. Our algorithm can be applied to lattice simulations that include minimally coupled fields and an arbitrary number of non-minimally coupled scalars, with the expansion of the universe sourced by all fields present. This includes situations when the dynamics become fully inhomogeneous, fully non-linear (due to e.g. backreaction or mode rescattering effects), and/or when the expansion of the universe is dominated by non-minimally coupled species. As an example, we study geometric preheating with a non-minimally coupled scalar spectator field when the inflaton oscillates following the end of inflation.
ISSN:2542-4653