Can we just use the uncertainty principle to explain something from nothing? [closed]

Question

I have been following the argument related to the early universe and the emergence of matter-energy from nothing.

They often refer to the notion of quantum fluctuations.

But I wonder if a simple explanation goes like this, instead:

Since in the early universe, the scale factor in the Standard Model approaches to zero, we could say that the volume of spacetime, in the proper frame, is arbitrarily small and therefore the uncertainty of spacetime is close to zero. As a result, the uncertainty of momentum-energy must be arbitrarily big, close to infinity.

So, one can conclude, simply using the uncertainty principle, that close to the big bang singularity, infinite momentum-energy is available in the early universe, which evolves first into radiation dominated and then matter dominated cosmos.

Is this argument correct?

My key question is about the origin of the super hot state, or infinite amount of energy, of the early universe, and NOT related to the later stage, i.e. formation of matter and anti-matter and leptogenesis.

Put it another way, are we talking about quantum fluctuations of the vacuum to basically mean an application of the uncertainty principle in a universe so compact that the uncertainty of spacetime is almost zero and hence the momentum-energy uncertainty is almost infinite?

Answer 1

I don't believe we can say your argument is correct because you are applying the regular quantum uncertainty principle in a domain which clearly calls for a quantum theory of gravity (which we currently lack). We don't know to what extent the eventual quantum theory of gravity will leave the uncertainty principle unmodified. Nevertheless, this is an interesting question to ponder.