The first would require a treatise. I'll see if I can search up a cogent link tomorrow.
As for the second, here's an old FR thread about an underappreciated demonstration of the quantum nature of gravity.
Specifically is a field or a wave quantized?
I don't really understand the question "is a wave quantized"; I might recommend that you read up on "particle/wave duality". As for fields, we know that the electromagnetic field, the weak nuclear field, and the strong nuclear field are all quantized, meaning that they can be modelled as the exchange of "force particles". We don't know mathematically how to do that with gravity, yet.
First of all, if "dark energy" is accelerating universal expansion, why don't we see a uniform acceleration? Second, why don't we see this impact on a micro level?
Third, what do the equations and data say? We know, for instance, that Gravity is inversely proportional to distance.
Well, if Gravity has anything to do with universal expansion, then that inverse proportionality will be evident in the modeling equations and research data.
Is it?!
In the same way, the pull of gravity should make particles fall into discrete energy levels. But because gravity is extremely weak on small scales, the effect has been impossible to spot. "To be able to measure it, you need to suppress interference from all the other fields...."
What an ingenious experiment, Physicist! Thank you so much for the link.