It is emphasized by Mr. bradenberger the concept of super hubble subhorizon fluctuations. I appreciate the idea that hubble radius and horizon are different ideas since they are physically distinct and partical horizon depends on the dynamics of cosmos evolution while hubble radius only depends on current state of scale factor. But when we talking about the metric fluctuation of a certain initial physical wavelength streches outside the hubble radius during inflation ,is it still inside the horizon?the answer is no if inflation have no start.But if before inflation there's an radiation of matter domination era, simple calculation shows up the the answer is yes.And the preinflation cosmic dominating guys should have an equation of state index bigger than 1/3,which is that for photon.Can there be something have EQS bigger than 1/3 and dominate the universe before inflation?(adsbygoogle = window.adsbygoogle || []).push({});

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Super hubble and subhorizon fluctuations

**Physics Forums | Science Articles, Homework Help, Discussion**