From Possibility to Actuality in the Quantum World 2024?

As the New Year is approaching bringing possibilites into actualities it may be worth while to contemplate the difference between modern physics of indeterminism and classical physics of determinism.  

After 100 years of brooding there is still no consensus about the physical meaning of the multi-dimensional Schrödinger equation in multi-dimensional configuration space as the basic mathematical model of Quantum Mechanics as the incarnation of modern physics. It is not likely that this will change in the future.

The big trouble is the multi-dimensional configuration space, of dimension $3N$ for a system with $N$ electrons, as representation of possibilities or probabilities, while physics in 3d space is all about actuality. 

This is expressed in the so called multi-verse interpretation of QM, where all possibilities are viewed as actualities, but this is convincing to only a few. Even more troublesome, the multi-d Schrödinger equation is uncomputable for $N>4$ as noted by Nobel Laureate Walter Kohn, who developed Density Functional Theory DFT as a reduced computable model.  

The break-through of QM in the 1920s came from a deterministic prediction of the spectrum of the hydrogen atom with $N=1$, thus in 3d space in stunning agreement with observation. The door was then opened to $N>1$ by a direct purely formal mathematical generalisation borrowed from linear algebra in any number of dimensions, however at the loss of physicality in a step from actuality to possibility. 

And there we are 100 years later with an unfathomable space of possibilities hiding actuality in the form of standard QM without physicality. But is it not true that stdQM can accurately predict the spectrum of any atom by clever approximate solution of the multi-d Schrödinger equation such as DFT as an actuality leaving out all other possibilities as being of little interest? Yes maybe so, but everything depends on a clever reduction of the multi-d Schrödinger equation, which can always be done so as to match observation, and so pull out actuality from possibility/probability. 

But, what is then the role of the multi-d Schrödinger equation if it is uncomputable and so anyway must be reduced to computable form? Why not instead seek to give some reduced model a physical meaning leaving the multi-d model to endless speculations by philosophers of quantum mechanics in the spirit of  medieval scholastics?

Recall that the by stdQM postulated erratic stochastic probabilistic unpredictable behavior of quantum particles like electrons around an atom being nowhere and everywhere at the same time, is nothing which can be verified by experiments, since tracking of individual particles by postulate is impossible. It is thus not possible to verify the validity of the multi-d model experimentally, and so it cannot be elevated from pure speculation based on mathematical convenience. You can thus choose to believe in this model, or not , without any notable practical consequence, just as the angels on knives edge by the scholastics.

This leads to RealQM, as an alternative to stdQM, which has a direct physical interpretation in terms of non-overlapping electron charge densities, and which is  readily computable and so shows very good agreement with observation. Maybe 2024 will open to a breakthrough of RealQM, as a possibility becoming reality?

PS1 After a lengthy conversation with ChatGPT, it is agreed that atomic spectra in experiments appear fully deterministic and so cannot be used as verification of the basic postulate of stdQM of probabilistic origin of atom physics. ChatGPT as a language model follows logic admitting that there is a difference between deterministic and probabilistic and that atomic spectra are deterministic and not probabilistic. This logic would be hard for a real modern physicist to accept following the cryptic illlogic of Bohr viewing contradictions simply "complementary" in a "duality" without contradiction: 

• A great truth is a truth whose opposite is also a great truth.
• Contraria sunt complementa. Opposites are complementary.
• We are all agreed that your theory is crazy. The question which divides us is whether it is crazy enough to have a chance of being correct. My own feeling is that it is not crazy enough.

What a sad story.When logic breaks down, reason breaks down and so rational science, and what remains is fiction science, which is not even science fiction (which like rational science is based on reason). 

PS2 About stdQM:

• Quantum mechanics is weird (Weinstein, Rovelli, Hossenfelder 2022)
• Quantum mechanics isn't as weird you think; it is weirder (Scientific American 2023)

Note that the Scientific American article first gives 3 examples where stdQM after all is not weird at all, and then concludes with something claimed to be really really weird, in order to maintain the official image that stdQM is so weird that more public funding must be given to physicists to clear up the mess. A clever tactic which has worked fine for 100 years.