The impact of Bohr-Einstein dialogs on thinking in quantum gravity: BSM in IR

Bohr, to my understanding, suggested that quantum theory was exact, or at least good enough for studying problems of the day. Today this accepting of Bohr's belief is implicit in applications of quantum field theoretic methods to arrive at a quantum theory of gravity valid at the Planck scale. It could be called the UV first approach.

Einstein, on the other hand, thought that quantum theory is approximate. That quantum non-locality and special relativity contradict each other, and that an underlying theory will quantitatively explain the origin of quantum indeterminism. These are not just UV issues. They concern low energy quantum mechanics as well. Quantum relativists worry about the loss of classical spacetime when quantum systems are in a superposition of two different position states. This could be called the IR approach to quantum gravity.

Both approaches are important and necessary. However a major recent realisation for me has been that the free parameters of the standard model are determined, not in the UV region, but in the IR region, by replacing Minkowski spacetime by its non-commutative analog. With hindsight, this paradigm shift becomes inevitable. But it is impossible, almost, to convince physicists of the UV approach about this. There is complete disbelief on their part. That is a Bohr way of thinking. The IR way of thinking is the Einstein way: quantum theory and special relativity are incompatible, and this is not just about quantum non-locality. It is about understanding the standard model. By sticking only to the UV approach we will never know why the low energy FSC is 1/137 and why the mass ratios are what they are.

I try to explain this in the attached sketch .

One can go from Minkowski spacetime vacuum to QFT at high energies, and then Planck scale, and make spacetime non-commutative.

Or one can go from Minkowski spacetime to non-commutative Minkowski spacetime, and then go to high energies and Planck scale.

Only the second method is correct. Because the ground state of quantum gravity is not Minkowski spacetime. It is non-commutative Minkowski spacetime. When quantum gravity is switched off, only the gravity is switched off. The quantum still remains. And quantum systems give rise, not to Minkowski spacetime, but to non-commutative Minkowski spacetime, Only classical systems can give rise to Minkowski spacetime, in the weak gravity limit.