About Jordan and Einstein Frames: A Study in Inflationary Magnetogenesis
Joel Velásquez,
Héctor J. Hortua,
Leonardo Castañeda
Affiliations
Joel Velásquez
Grupo de Gravitación y Cosmología, Observatorio Astronómico Nacional, Universidad Nacional de Colombia, Cra 45 # 26-85, Ed. Uriel Gutierrez, Bogotá 16486, Colombia
Héctor J. Hortua
Grupo Signos, Departamento de Matemáticas, Universidad el Bosque, Bogotá 11321, Colombia
Leonardo Castañeda
Grupo de Gravitación y Cosmología, Observatorio Astronómico Nacional, Universidad Nacional de Colombia, Cra 45 # 26-85, Ed. Uriel Gutierrez, Bogotá 16486, Colombia
In this paper, we make a detailed side-by-side comparison between Jordan and Einstein frames in the context of cosmic magnetogenesis. We have computed the evolution of the vector potential in each frame along with some observables such as the spectral index and the magnetic field amplitude. We found that contrary to the Einstein frame, the electric and magnetic energy densities in the Jordan Frame do not depend on any parameter associated with the scalar field. Furthermore, in the Einstein frame, and assuming scale invariance for the magnetic field, most of the total energy density contribution comes from the electric and magnetic densities. Finally, we show the ratio between magnetic field signals in both frames printed in the CMB.
