Subject: What is wrong with a universe with zero energy density?

Since MASS-ENERGY is conserved; energy density  ED defined as 
ED=MASS-ENERGY /Volume can indeed go to zero as volume  V approaches infinity 
e.g.   an infinite universe with zero curvature
Is this forbidden by any known laws including GR
Further if the big bang started with quantum particles that  were compressed 
by gravity forces (Guv=8PiTab) 10^50 times the Coulomb forces (spacetime 
curvature);why is their a need to unite QM and GR.The inability to solve QED 
aka Schroedinger's equation even for 10 or 15 particles inplies unification is 
a fruitless search for separation of the"chicken (mass energy)"-"egg"  
particles 
argument.They"chicken (mass energy)"-"egg" are one and the same ;it's a 
scaling problem

Re: What is wrong with a universe with zero energy density?