I Would these (unrealistic) conditions imply gravitons existed?

[NotASmurf]

So quantum states collapse when observed, ie they are interacted with, if one had an uncharged massive particle, in a true vacuum (yes, this assumption is egregious, not your usual "ignore air resistance"), and the state of the aforementioned particle collapsed, would that imply gravitons did exist, because there would be no other particle to interact with it?

 

[Grinkle]

Jumping into the deep end ...

Particles can be kept in a state of superposition in the midst of all our gravity. So if you are correct in your hypothesis then I think the same reasoning (inverted) might apply to say that gravitons do not exist.

Or that the presence of gravity does not disturb superposition.

 

[PeterDonis]

quantum states collapse when observed, ie they are interacted with

Only on a collapse interpretation of QM. There are also no collapse interpretations, such as the MWI. "Collapse" is not something that is directly observed, so I don't think your question is well defined.

 

[NotASmurf]

You're 100% right, terribly phrased question on my part, I butchered physics like how engineers ruin math