# Gravity: The explanation for quantum statistical effects?

1. Jul 21, 2011

### Schreiberdk

Hi PF

I was wondering about the problem of quantum gravity, and maybe the reason why we struggle so much with a formulation of quantum gravity is, that spacetime itself is the source to all quantum phenomena.

The evidence is, that with the standard model, we describe the quantum phenomena, except the gravitational quantum phenomena. Now the standard model is all the physics inside spacetime, but what about spacetime itself? Could it be, that it is spacetime that is causing all the quantum behaviour of particles, like wavefunctions etc., and that spacetime then does not have a quantum description, since it is the source of quantum phenomena, and thereby is deterministic in structure?

\Schreiber

2. Jul 21, 2011

### dhillonv10

Schreiber, we struggle to formulate a proper theory of quantum gravity because we don't yet understand a lot of the concepts, for instance, the concept of space has been very well developed, we even speculate that space itself may be emergent of some deeper phenomenon, but what about time? Einstein linked those two together however we don't even understand the basics of what time is besides some links to entropy. Currently the most complete description of QG that we have is AdS/CFT but even in that theory, we generally take static patches, defining regions of space relativistically (meaning with some notion of time) is a very difficult task, mathematically. Now if I understand correctly, what you've stated, spacetime is indeed the "playground" where all phenomenon occurs. The main objective of QG is to present a theory that can unify GR and a formulation of string theory, once that happens, spacetime description from GR can be taken as is. String theory does a decent job of that, and it is because of that reason we are able to speculate that space might be emergent of some deeper phenomenon.