In the standard inflationary scenario, the power spectrum is evaluated at the cosmological time when one assumes an equation of state [itex] $ P= \omega \rho$ [/itex] , that is, one is assuming a particular radiation or matter dominated universe. Why does it has to be in these cosmological epochs? does it involve something about the physical scale of the perturbations reentering the Hubble horizon and then one treats the perturbations as classical fields?.(adsbygoogle = window.adsbygoogle || []).push({});

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# Why does power spectrum is calculated at the radiation/matter epochs?

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