Title: A gravitational self-decoherence model and a gentle recovery of the classical world
Abstract:
1. We briefly discuss the reductionist program of reclaiming the classical world from quantum physics.
2. Next, we argue that (i) relativistic spacetime theory supplemented by (ii) QM forbids measuring distances ℓ ≲ 𝐿Planck.
3. This is used to argue that current QM cannot describe particles with ƛ ≲ 𝐿Planck (𝑚 ≳ 𝑀Planck).
4. Then we impose a Heisenberg cut at 𝑚 ∼ 𝑀Planck separating quantum particles (𝑚 ≪ 𝑀Planck) from classical particles (𝑚 ≫ 𝑀Planck).
5. A minimal (Lorentz-invariant) gravitational self-decoherence model is presented to describe the new physics at the Heisenberg cut.
6. Free quantum particles experience some self-decoherence as 𝑚 → 𝑀Planck.
7. Although our model prohibits, say, crystals with 𝑚 ≫ 𝑀Planck from being in spatial superposition, it does not prevent them from hosting superpositions of phonons as seen in the Lab.