Quantum mechanics and the measurement problem
Quantum Mechanics (QM) is a very successful mathematical description of how atomic events unfold, and can gives us a very successful way to compute how quantum waves and particles behave.
But it also left us with many questions of how reality may work. At the core of this is the measurement problem, where -- when we look at the math -- it appears as if only a measurement done by a conscious observer collapses the smooth wave function that contains all possible solutions abruptly and randomly into a single one that we then can observe, say an electron or photon.
Why that one? You see, QM is extremely good at describing how, but not why. Unlike classical mechanics we cannot predict with deterministic certainty what will happen during a measurement, but only give probabilities.
For example, during the double slit experiment, we can only predict the probability of where the eventual photon will land, but cannot say with certainty exactly where. Furthermore, when we set up the measurement of the experiment one way, it will reveal the wave nature of matter (showing the classical wave interference pattern), and the particle nature when we set it up differently.
It is as if the consciousness of the outside observer, that is how he or she queries reality during the measurement, determines this slice of reality. In a way, the question predetermines the answer we can get.
It all seems very strange and different form the world we are used to.
The world of the quantum appears to be a world of randomness, certainly a randomness within a framework, the framework of QM, but still highly random.
It appears as if God is playing dice (Einstein).
Quantum Physics Interpretations
So while the math of QM is very clear, at the same time it opened up many questions. For example, is consciousness involves in setting up the result? And why does it seem so random? Is there a deeper reality behind all this that drives this?
Besides giving us answers, quantum physics also gave us an enigma.
In order to answer these questions, we have had several attempts to “interpret” what the math is saying. All of them use that same math, but differ on what the math may mean.
Below, I list the original interpretation and several later alternatives, with Bohm’s (#2) and Everett’s (#3) being the two best known. I also list the transactional interpretation (#4), which I discuss in more depth in another post.
The Copenhagen Interpretation.
The historically first, and still the most prevalent, interpretation is the so called Copenhagen Interpretation. This is an epistemological interpretation, meaning it is concerned with the limits of what we can know. It basically states the math is in fact all we can know, and there is nothing more that can be discovered. Essentially it amounts to saying, don’t ask philosophical questions, just shut up and compute. And that is exactly what happened for several decades…
Of course, this is a highly unsatisfying dogma, because it is in the nature of man to know.
And thus, subsequently, starting from the 1950s there were several other interpretations, the first one being:
- The Bohm / DeBrogli pilot wave interpretation. [article upcoming].
The key idea is that there is an additional universal field called the “quantum field” that guides particles along their paths, thus “a pilot wave.” Events are no longer random, but there are “hidden variables” that thereby determinately govern how objects behave. In later years, Bohm argued that at this deeper level of reality everything becomes enfolded in some “implicate order” which has a holographic aspect to it – a point often argued in these posts. There is order, but it so finely intermixed, that we cannot discern it at our level.
- Hugh Everett’s “Many-World-Interpretation.” [article upcoming]
QM predicts how quantum states form mixed states (so called "superpositions") until an observer collapses this system into a measured result. There is a sudden break in continuity and out of all the possible states, only one result becomes real and measurable. Why? Everett takes the bull by the horns and says the reason for this is because there is no measurement problem at all. It is an artificial problem because we treat the observer as something different or special apart from the rest. Really, if there are N solutions, then all N solutions become real and the universe splits into N universes, only we do not notice as we happen to live in only one of them. Subsequently, this became named “the many world interpretation” by DeVitt. Of course, this subsequent splitting quickly leads to infinities upon infinities of universes. Still, while at first ignored by all but science fiction fans, the theory has by now become established scientifically as a real option.
- John Cramer’s Transactional Interpretation (read more)
is different because it is time symmetric. The central idea is that in all physical events a transaction is formed between an emitter and an absorber. In order to create these transactions, the emitter sends an offer wave FORWARD in time, and the absorber sends a confirmation wave BACKWARDS in time. While this may sound impossible, (almost) all formulas in physics are in fact time symmetric: you can run them forward and backwards. The beauty of the interpretation is that it resolves many of the paradoxes that the Copenhagen interpretation left us with.
- Various others, arguably lesser known. You can see a full list on wikipedia.
Each one of these has their proponents and opponents.
Personally, I like aspects of #2, #3, and #4, and believe what may be going on is some sort of combination.
Namaste — I bow to you and the Divine in you.
Copyright © Hanns-Oskar Porr