Understanding the Spectral Energy of the Vacuum: A Scientific Exploration

[Apollo2010]

Hello,

I have seen in various places in the literature the expression for the spectral energy of the vacuum, but I don't seem to find a book/article where the derivation of this expression is shown.
Also sometimes people state at its dependence on the third power of frequency is the only form compatible with Lorentz invariance.
Do you know where I could find out how this is shown, too?
Thank you!

 

[Simon Bridge]

have seen in various places in the literature

... where? Which places? Please provide an example.

I don't seem to find a book/article where the derivation of this expression is shown.

... quantum cosmology textbook?

Is it more that you don't know what "spectral energy of the vacuum" means?
Have you tried looking up the definition of "spectral energy"?
Looks like you need a dictionary of technical and scientific terms - find one at your local library.

Have you seen discussions like:
http://iopscience.iop.org/1742-6596/174/1/012007/pdf/1742-6596_174_1_012007.pdf
... but context is going to be very important for your question.