Lumo ‧ 7 years ago

Dear Anonymous,

I agree that loop quantum gravity may also be viewed as an attempt to make sense out of the WDW equation. Unfortunately it is not a consistent or successful attempt – simply because the Hamiltonian constraint can’t be defined. (In fact, even the physical Hilbert space is not well-defined.) See an older article “A very meaningful paper on loop quantum gravity”.

All the best
Lubos

Anonymous ‧ 7 years ago

But even the Wheeler-deWitt equation needs to be regularized!

Lumo ‧ 7 years ago

That’s right. This is why you need string theory to transmute the WDW equation from a heuristic speculation to a meaningful law of physics.

— Lubos Motl

2012.08.02 Thursday ACHK