**Abstract**

It is suspected that the quantum evolution equations describing the micro-world as we know it are of a special kind that allows transformations to a special set of basis states in Hilbert space, such that, in this basis, the evolution is given by elements of the permutation group. This would restore an ontological interpretation. It is shown how, at low energies per particle degree of freedom, almost any quantum system allows for such a transformation. This contradicts Bell's theorem, and we emphasise why some of the assumptions made by Bell to prove his theorem cannot hold for the models studied here. We speculate how an approach of this kind may become helpful in isolating the most likely version of the Standard Model, combined with General Relativity. A link is suggested with black hole physics.

**Keywords:** foundations quantum mechanics, fast variables, cellular automaton, classical/quantum evolution laws, Stern-Gerlach experiment, Bell's theorem, free will, Standard Model, anti-vacuum state

### **1. Introduction**

Since its inception, during the first three decades of the 20th century, quantum mechanics was subject of intense discussions concerning its interpretation. Since experiments were plentiful, and accurate calculations could be performed to compare the experimental results with the theoretical calculations, scientists quickly agreed on how detailed quantum mechanical models could be arrived at, and how the calculations had to be done.

The question what the intermediate results of a calculation actually tell us about the physical processes that are going on, remained much more mysterious. Opinions diverged considerably, up to today, one hundred years later.

The historical events that led to this situation are well-known, and have been recounted in excellent reports [1]; there is no need to repeat these here extensively. It was realised that all oscillatory motion apparently comes in energy packets, which seem to behave as particles, and that the converse should also be true: all particles with definite energies must be associated to waves. The original descriptions were somewhat vague, but the year 1926 provided a new landmark: Erwin Schrödinger's equation [2]. Originally, the equation was intended to describe just one particle at the time, but soon enough it was found how to extend it to encompass many particles that may be interacting.

Indeed, in his original paper, Schrödinger went quite far in discussing Hamilton's principle, boundary conditions, the hydrogen atom and the electromagnetic transitions from one energy level to an other. One extremely useful observation was made by Max Born [3]: the absolute square of a wave function, at some spot in position space, must simply stand for the *probability* to find the particle there. This made a

lot of sense, and it was rightly adopted as a useful recipe for dealing with the equation.

But then, many more questions were asked, many of them very well posed, but the answers sound too ridiculous to be true, and, as I shall try to elucidate, they *are* too ridiculous to be true. I am not the only scientist who feels taken aback by the imaginative ideas that were launched, ranging from the role of 'guiding pilot' adopted by the wave function [4] to steer particles in the right direction, to the idea that infinitely many 'universes' exist, all forming parts of a more grandiose concept of 'truth' called 'multiverse' or 'omniverse', an idea now known as the 'many worlds interpretation' [5, 6].

In contrast, an apparently quite reasonable conclusion was already reached in discussions among scientists in the 1920s, centred around Niels Bohr in Copenhagen, called the 'Copenhagen Interpretation'. They spelled out the rules for formulating what the equations were, and how to elaborate them to make firm predictions. Indeed, we know very well how to use the equation. The properties of atoms, molecules, elementary particles and the forces between all of these can be derived with perplexing accuracy using it. The way the equation is used is nothing to complain about, but what exactly does it say?

Paul Dirac for instance, advised not to ask questions that cannot be answered by any experiment; such questions cannot be important. We know precisely how to use Schrödinger's equation; all that scientists have to do is insert the masses and coupling parameters of all known particles into the equation, and calculate. What else can you ask for? Many of my colleagues decided to be strictly 'agnostic' about the interpretation, which is as comfortable a position to take as what is was for 19th century scientists to stay 'agnostic' about the existence of atoms.

The Copenhagen verdict was:

*"There are many questions whose answers will not be in the range of any experiment to check; there will be no unanimous agreement on the interpretation of the equations, so stop asking."*

The present author accepts all conclusions the Copenhagen group had reached, except this last one. It will be important to ask for models that can elucidate the events that take place in an experiment. We do wish to know which sensible models can in principle explain the Schrödinger equation and which will not.

What happens to its wave function when you actually observe a particle? What does it mean if the Schrödinger equation suggests that interference takes place between different possible paths a particle can take? Those questions I can now answer, but others are still way out of reach: the masses and coupling parameters of the elementary particles have been determined by experiment, but we do not have acceptable theories at all to explain or predict their values. If the history of science is something to be taken to mind, it may be that asking unconventional questions will lead to better insights.

The Schrödinger equation is simple and it works, but some of the explanations why it works seem to get the proportions of a Hieronymus Bosch painting. This does not sound right. Almost a full century has passed since the equation was written down, and we still do not know what or whom to believe, while other scientists get irritated by all this display of impotence [7]. Why is it that we still do not agree?

I think I know some of the answers, but almost *everyone* disagrees with me. I have reached the conclusion that quantum mechanics indeed describes a completely deterministic world. Admittedly, I will leave some questions unanswered. The origin of the symmetries exhibited by the equations is not well understood. More advanced mathematics will have to be employed to answer such questions, as will

#### *Ontology in Quantum Mechanics DOI: http://dx.doi.org/10.5772/intechopen.99852*

be explained. Sharpening the scope of my claim, the point is that there is no mystery with quantum mechanics itself. Just leave questions concerning symmetries aside for the time being. In contrast with what others proclaimed, there is no logical conflict. This will be explained (Section 5).

What *are* those masses and coupling strengths? Do particles exist that we have not yet been able to detect? Isn't it the scientist's job to make predictions about things we have not yet been able to unravel? These are questions that are haunting us physicists. We have arrived at a splendid theory that accounts for almost anything that could be observed experimentally. It is called the *Standard Model* of the subatomic particles. But this model also tells us that particles and forces may exist that we could not have detected today. Can we produce any theory that suggests what one might be able to find, in some distant future? And as of all those particles and forces that we do know about, is there a theory that *explains* all their details?

Today's theories give us little to proceed further from where we are now. The Standard Model explains a lot, but not everything. This is why it is so important to extend our abilities to do experiments as far as we can. Recently, audacious plans have been unfolded by the European particle physics laboratory CERN, for building a successor of its highly successful Large Hadron Collider (LHC). While the experimental groups working with the LHC have provided for strong evidence supporting the validity of the Standard Model up to the TeV domain, theoreticians find it more and more difficult to understand why this model can be all there is to describe what happens further beyond that scale. There must be more; our present theoretical reasoning leads to questions doubting the extent to which this model can be regarded as 'natural' if more of the same particles at higher energies are allowed to exist, while the existence of totally new particles would be denied.

Inspired by what historians of science are telling us about similar situations in the past history of our field, investigators are hoping for a 'paradigm shift'. However, while it is easy to postulate that we 'are doing something wrong', most suggestions for improvement are futile; suggesting that the Standard Model would be 'wrong' is clearly not going to help us. The 'Future Circular Collider' is a much better idea; it will be an accelerator with circumference of about 100 km, being able to reach a c.m. collision energy of 100 TeV. The importance of such a device is that it will provide a crucial background forcing theoreticians to keep their feet on the ground: if you have a theory, it better agree with the newest experimental observations.
