No physical theory proved to be complete since now, and there are many reasons to believe that Quantum Mechanics is also not complete. Most theories were only approximations of the reality and proved to be true (appliable) only in a given domain of energy, magnitude, mass, velocity - see Newton's Mechanics. This is the most common form of incompleteness of a physical theory. There is also another form of incompleteness, where the theory cannot do predictions even in the chosen field of application. This is the case with the wave function in a measurement. Quantum Mechanics has put itself proper borders of predictability, see Heisenberg's Uncertainty Relations. However, there are exactly those forms of incompleteness which finally produce the Progress - which normally consist in the addoption of a new model, with a new theory.

On the basis of their observation using the technology of their time, Ptolemi formulated the geocentric theory of the solar system. However Galileo (and Copernicus-delete), because of the arrival of the spy glass or telescope were able to go beyond the limited observation of Ptolemi. The heliocentric theory seems to be a heliocentric fact already.

This could be true to the Physical theory of QM. New, advanced technology can make human perceptions sharper, keener, and more reasonable.

Eddie,

there was not spy glass in Copernicus times. His decision was purely mental, as well as Einstein's and so on.

I stand corrected Eugene. It was in Galileo's time. Sorry for that. Ed

You might find my paper on this subject of interest.  "Does the Quantum Mechanical Wave Function Have Any Physical Meaning?"  You can download it from my list of publications on ResearchGate.

Abstract:

The opinion that the wave function of quantum mechanics has no physical reality remains well entrenched. As a complex quantity, the wave function can supposedly correspond to nothing physical let alone to anything directly detectable. This point of view, I believe, has unfortunately discouraged research into the meaning of the wave function. However, the above logic proves erroneous because we need not use complex numbers at all. The use of a complex wave function, and a complex Schrödinger’s equation, merely serves as mathematical shorthand. It simply allows us to write two entirely real equations, with entirely real solutions, as a single equation. And, if we look at those real equations and solutions, we find parameters that can have entirely physical meanings.

First of all we have to understand that whatever has the prefix 'quantum-...' is just another linear mathematical tool. So, in 'quantum mechanics' we have a linear operator (in differential form: Schroedinger or in matrix form: Heisenberg) that has eigenvectors (eigenstates |psii>) and eigenvalues (the physical observables from measurements). The fact that we can expand any state in a Fourier series expansion is rather a curve fitting trick: We could also have an infinite set of expansions, based on other functional bases, diefferent from eix )

So, as long as the physical phenomenon can be explained well by a linear mapping (hermitian operator with real eigenvalues), then we are free to use the Fourier series expansion. But, every term of this series is not a living entity! 

Otherwise we would end up with an infinity of living entities, each one for every possible series expansion...

At issue is not just QM, but that is a good enough starting point.  QM is mostly particle families and their relative 'physics', or mathematically modelling with 'high' predictability.  Gravity is included in some QM theories, creation myths like Big Bang, and dozens of physic mysteries come to mind, that mankind, as of this year, 2014, has seen the tip of the iceberg, and probing deeper, creative thinking, original thought, is requiring a change in paradigm(s).  This first reply of mine is limited to QM, at a very high level.

I start by pointing out the problem as stated is a leading question.  That is, it assumes QM has one interpretation, and could be 'right' - It most certain is not right, at least not until it includes gravity, and more.  Or has something missing - which it might not be missing anything, just no one has yet to understand the 'full' mathematical treatment and interpretation - adding equations already known to mankind. Thus, I wish to broaden the question, to encompass other aspects of Physical Reality (that slippery daemon).

For example, "pilot-wave theory", an alternative to Copenhagen, has recently gotten two boosts, where one boost is a macroscopic fluid dynamic experiment that simulates the results of the two slit experiment.  There are 7 or more additional interpretations that disagree with the Copenhagen interpretation, and with each other.  Each interpretation varies, to some degree, with everything in this 'leading' question.  So, a third position, maybe more, are possible, to response to the primary question, what are the current views and thinking.

It could be said that mainstream QM scientists, contemporary popularity contest winners (funding), certainly are seeing Cohenhagen as the end result.  And from there, are self limiting to see the rest of the iceberg?  Leaving much on the table?

Is there room in this thread for a personal viewpoint?  I think so.

My personal view, not a popular one, nor one likely many have read about, is keeping a place for 'man' in the observations is much like keeping the Earth at the center of universe.  One not only must take it on faith, the question arises, what 'part' of the Earth is at the universe's center?  Rome?  The Vatican?  What part of those? 

What part of man needs to do the observing?

I find no beauty in the Cohenhagen Interpretation.  All the alternatives do not turn a new leaf, are not paradigm shifts, imho.  Offer little integration with GUT and TOE.

That energy needs to be grouped as particle or wave, I think is man casting a stereotype, simplifying a problem, by ignoring key parts.  Parts like the energy is different from the QM state.  Where the QM state is more important than the wave energy make up.  I'm not agreeing with this viewpoint, as it too separates the problem into two parts.

I'm not even sure the question as asked, is even a question.  More a call for a summary of contemporary thinking.  And published and widely read ones at that.  Thus, it took me three days, to figure out my reply angle.  And I am still not pleased with it. 

I await more posts, and I will post again the rest of my view point of where QM stands regarding Physical Reality, where I might toss in the rest of Physics.

I hope Professor Menon might post to limit the question to just QM.  And add his answer.  Retirement can bring many fruitful thoughts to the forefront of the mind.  There is much room for original thought to bring Physics to match Physical Reality.  I do enjoy thinking about his question.

Many recent references discuss the current status of this controversial topic; for example, Max Tegmark "Our Mathematical Universe"; and, Marcus Chown "The Universe Next Door".  My reaction to these books is mixed.  I see a potential issue in the popular "Many Worlds" interpetation, since it seems to permit "magic" to exist to some extent, but it seems to satisfy the mathematical description of reality.  Perhaps the uncertainty printciple, or some other restriction on the "mathematical many worlds" will remove the magical quality in the instantiations of the "physical many worlds" interpretation.

The question, as posed here, seems to imply an unnecessary correlation of QM "interpretations" with the antropocentric (not geocentric) issue.  It would be easier to respond to questions about the nature of physical reality if this issue were not injected into the discussion, since it diverts the whole question into a discussion of philosophy.  Personally, I see no correlation.  If others see it, I suggest the response that "Correlation does not  causation".

Can others suggest current and scholarly references on this topic?

DH Stevans,

all our views are inevitably antropocentric. Now, also, antropic principle in physic exists. Of cours, correlation does not causation. Moreover, causation is first of all human will (way of thinking). It may not exist in nature. In some sense relativity is an example.

Regards,

Eugene.

A scientific theory can at best give an efficient representation of the real world, and it is always perilous to assume some bizarre properties for the real world in order to comply with a theory.

The issue is that QM is a mixture of physical assumptions about particles and fields (that is at a small scale leve) and axioms (Hilbert spaces, eigen values,...) which are popular because people have learnt to compute with them. These axioms, mostly framed by von Neumann, are actually basic properties of any model using mathematical representations of a general kind. Almost all the axioms can then be proven, and they do not contain any physical content. Of course, because they are valid, and can be used, an it is useful to have a look at what they mean, but it is unnecessary to make bizarre assumptions about "reality". In particular the vector in Hilbert space, which represents the state of a system, represents the state of a system along its whole evolution (this is similar to the implementation of the principle of least action : the lagrangian must be accounted for the whole evolution, in space and time). As a consequence the state vector corresponds to a map, and has no arguments, and there is no mystery about its collapse.

For more see mypaper on "QuantumMechanics Revisited" on this site. There is no exotic assumptions, no multiuniverse, no magic, just basic maths.

Eugene,

        Thanks for the reply.  Regarding the antropocentric issue, we can endlessly discuss either the correspondence theory of truth (physical reality corresponds to our observations), or the coherence theory of truth (reality consists of our mental structures).  The coherence theory may be viewed as antropocentric, as you say, with relativism as a correlate.  When I say "Correlation is not causation.", I am referring to the correspondence theory, where the ontological nature of truth seeks causes, and describes the existence of objects outside of our antropic views. 

     The coherence theory, as you correctly point out, does not need to address the existence issue, since it only requires a coherent structure within the human "way of thinking".  The coherence theory seems to apply to the Copenhagen interpretation of QM, while the correspondence theory (and other theories of truth) might appeal to those like Tegmark's "Many Worlds" interpretation of QM, which says that QM expresses the actual existence of "all possible worlds" which could result from the collapse of the wavefunction.  As I said, I find this incoherent because it requires the existence of an entire universe for every possible wavefunction instantiation, which seems to allow for "magical" events.

    Does anyone know of any current and scholarly references on the subject of these interpretations?

Thank You for explanation of the terminology, DH.

To my mind we have to distinguish between possibilities, as our future, and facts, as our past.

Regards,

Eugene.

Dear All

Thank you very much for the stimulating discussions. 

best wishes

menon

Manuel,

that QM is not complete theory is known without any experiments. The question is about alternatives.

Regards,

Eugene.

The David Bohm's theory of Quantum Physics has the real Reality.

You mean holografic picture, Dmitri?

First, in the question we sould agree on the existence of a "physical reality", that is a world where things happen without any interaction from our part (this is not obvious for some people).

Then we have to agree on the purpose of science : to provide a rational and efficient narrative to explain and act on this reality.

And the issue is that there is a discrepancy between our narrative and reality. This is not new, and this is unavoidable : in any scientific model one focuses on some points which are deemed important and neglect the rest (for efficiency). The real trooubles came with relativity and QM.

Relativity taught us that the way observers see space and time depends on the observer. In a 4 physical dimensional universe we can formalize (and imagine) something which extends in the past in the future. Does that mean that they exist somewhere ? The only way to solve this paradox is to acknowledge that each of us has a window through which he has a specific, partial, view of reality. We can imagine what exists out of this window, but our neighbour has another window, and not necessarily the same view. This is the reintroduction of the observer in Physics : every measure must be tagged by a label telling how and by whom the measure has been done, and all the apparatus of relativity allows us to patch together these partial measures.

With the Maxwell laws Physics repudiated the concept of action at a distance, and invented the concept of field. But, to act, fields must be present everywhere. One of the key component of any model of physics should be formalized by variables which are quantities defined by an infinite number of parameters. The model of Analytic Mechanics breaks down. Any physical measure relies on an estimation procedure, based on a finite number of data. To esimate a map depending on an infinite number of parameters we need at first to simplify its expression : we choose a specification which depends on a finite number of parameters, which can then be estimated. So we invented observables. And of course observables, how mathematically convenient, show bizarre properties : randomization, discreet values, quantization,...

In both cases Physicists have to acknowledge the discrepancy between what there is, and how they represent it. We can imagine a 4 dimensional world, and fields existing everywhere and propagating, this is convenient to build a rational narrative and develop new theories. This is right to keep this imagination in check by requesting validation by experiments. But we have to admit that the experimental proofs will always be biased, and partial. And so it is wrong to kill the imagination.

So Physicists have to stand guard against two dogmatisms : the one which pretends that our models and theories are the reality (if the computation rules are bizarre this is because the reality is bizarre). And the one which denies the possibility to ever conceive of a reality following rational and sensible rules (the empiricist point of view).