This may be a simple question but I didn’t found anything in my references: the vacuum energy density is a constant value, which depends on the virtual excitations of the quantum fields. If the universe expands, increases its volume, and the vacuum energy density remains is constant, does this...
Posing that O4 and O3 are energy density vectors, and Rp is momentum density value.
Could I write:
O4 = ( O3, icRp )
and therefore
(O4)2 = (O3)2 - (cRp)2
where (O4)2 is invariant under Lorentz transformation.
The point here, from what I learned from preceding posts, is to write something...