It’s Time to Move Beyond General Relativity
The quest for a complete theory of quantum gravity will require us to revise our assumptions about space-time
There are countless theorists working to apply general relativistic dynamics to quantum theory, but over several decades they have had very limited success. A proper theory of quantum gravity still seems very far away.
It’s common to say that GR works perfectly on big scales and QM works perfectly on tiny scales, but the incompatibility between the two is not just about macro vs micro. The world proposed by the laws of GR is fundamentally distinct from the world proposed by the laws of QM, beginning with their treatment of time.
In quantum mechanics, time is a classical background parameter, and the flow of time is universal and absolute. In general relativity, time is one component of four-dimensional spacetime, and the flow of time changes depending on the curvature of spacetime and the spacetime trajectory of the observer.
Perhaps, instead of asking if we can adjust QM to accommodate the laws of GR, we should be asking how we can adjust GR to accommodate the laws of QM.
For instance, can we get the observable space-time effects of General Relativity with a theory that uses time as a…
