The homogeneous and isotropic radiation dominated universe, following the inflationary stage, is expressed as a spherically symmetric and inhomogeneous spacetime upon a power law type conformal transformation of the null (cosmological) coordinates. This new metric has a few interesting properties. The symmetry of the metric offers a new unitarily inequivalent quantisation of the massless scalar field and provides a new example of particle creation in curved space. The new set of observers, detecting particles, are freely falling in asymptotic past and future and accelerated in between.
Tue, 13 Feb 18
Comments: 20 pages, 1 figure