Two papers have proposed a novel theory of spacetime, one in which it functions as a
mediator between the quantum physics and the classical physics as modified by Einstein. It's not clear whether this theory is true or workable, but they have figured out how to test the theory (if they can measure precisely enough).
A question this raises, were it true, has to do with what is fundamental. For a long time, since the quantum field became undeniably interesting, physicists have argued that the most basic reality was the wave equation, which we have discussed here recently a time or two. This is the one that requires "imaginary numbers"* (noting James' objection to the connotations of that phrase) in order to model reality. The most fundamental thing was the background field whose waves, as it were,* produce things that we observe and call things like "electrons." Those things then come together in various ways to produce everything else.
Because this theory requires spacetime to serve as a mediator between the quanta of the wave equation and the things that we observe at the larger scales of classical physics, there needs to be an explanation of where and how spacetime comes to be. Instead of the fundamental thing being the field in which the waves occur, producing particles (again 'as it were'*) at peaks and troughs, the waves must then necessarily encounter another thing. That other thing is spacetime. So where does it come from, and how did/do we get to the state in which the quanta necessarily interact with and are mediated by it?
Towards the end they note two important consequences of the theory, should it hold.
The postquantum theory has implications beyond gravity. The infamous and problematic "measurement postulate" of quantum theory is not needed, since quantum superpositions necessarily localize through their interaction with classical spacetime.
The theory was motivated by Professor Oppenheim's attempt to resolve the black hole information problem. According to standard quantum theory, an object going into a black hole should be radiated back out in some way as information cannot be destroyed, but this violates general relativity, which says you can never know about objects that cross the black hole's event horizon. The new theory allows for information to be destroyed, due to a fundamental breakdown in predictability.
So those consequences are:
1) Information can be destroyed, contrary to what we have long assumed was a fundamental law.
2) You don't actually need an observer to collapse
superpositions, as some have postulated, because the interaction with spacetime itself collapses them to definite states. That could explain why there appears to be a definite reality at great distances wherein we have no reason to suspect that there are observers (although you could also explain that in other ways).
* Some of these ways of speaking are imprecise natural language ways of trying to say what the math tells us. I don't apologize for using them, because it's more important to be able to talk about reality in natural language than for everyone to learn higher math. Nevertheless the clarifications of experts as to the limits of the language are useful and should be attended.
