Abstract
The electromagnetic perturbation equations are solved in a closed Robertson-Walker space-time; the frequency spectrum and the proper modes are found. A simple quantum theory of electromagnetic waves in the background metric is then developed using the proper modes of the static metric conformally connected with the closed Robertson-Walker metric. It is shown that the number of "photons" does not change as a result of expansion (or contraction). The application of these results to the cosmic background radiation is discussed.
- Received 13 March 1973
DOI:https://doi.org/10.1103/PhysRevD.8.4297
©1973 American Physical Society
