Source: Medium

Fermion Physics

The Copenhagen interpretation is one of the most popular interpretations of quantum mechanics, and it is the orthodoxy in physics. It is usually related to all the weird things about quantum mechanics you may have heard, like Schrodinger’s Cat. But what if I told you that the copenhagen interpretation of quantum mechanics — is wrong? Here’s why

Disclaimer

Before I write the rest of this article, I want to say that my beliefs here are not the orthodoxy in the physics world — most physicists believe the copenhagen interpretation and most of the rest don’t care. I’m not claiming to have made some new discovery. What I’m doing here is providing an argument against the Copenhagen interpretation. I’m not saying it is a complete fabrication. But what must be kept in mind is that most physicists believe the copenhagen interpretation simply because that is what is usually taught in universities. Many don’t really care to look for actual justifications or an alternative explanation. A majority of physicists agreeing does not make them correct, and it also does not make them wrong. Even though the measurement problem is not a settled issue, the arguments I present here will be as objective as possible and as reasonable as possible. If you disagree with any of my arguments, great! Tell me why I’m wrong in the comments. With all that said, let’s begin.

What is the Copenhagen Interpretation?

It would be great to start out by defining the copenhagen interpretation. The Copenhagen interpretation turns out to not be well defined, and there is many disagreement between self identified proponents, but the copenhagen interpretation could be summed up as

• Before a system is measured, it is described by a wave function, which encodes the probability of measuring certain properties of the system (such as energy, position, etc.,.)
• When the system is measured, the measurement is a single eigenvalue

These are the postulates of the Copenhagen interpretation.

The way the copenhagen interpretation is formulated is already problematic. It does not define what a measurement is, it does not talk about the eigenvalue of a system before a measurement, and it does not say why the wave function is related to the probability density. It turns out that this is by design. The copenhagen interpretation is intentionally formulated to be vague, and to just describe what is measured. If a scientist walks into a lab, and does a measurement, the wave function will indeed tell the scientist how likely he will get that measurement. The copenhagen interpretation could be thought as the instructions a medicine container has. “Take 1 pill each day and your sore throat will be cleared.” These instructions do not tell you how the pill clears your throat, it does not say what the pill is doing inside your body, it just tells you what happens. The same thing happens with the copenhagen interpretation. It just tells you what you’re gonna (likely) get, and dodges all other questions. For many physicists, this is satisfactory. They have a theory that can predict stuff, so why will they care more about what’s going on beyond the math? I will respond to this point later, but right now I want to give more arguments about why the Copenhagen interpretation is wrong.

Like I said earlier, it doesn’t say what counts as a measurement. Does the measurer have to be conscious? Does the measurer play by the rules of quantum mechanics? Does the measurer have to be outside the system? It doesn’t answer these. Does the system before measurement even have an energy? It doesn’t answer this either. All it does is it tells you what you might get. Some people will try to answer these questions though and still claim they are copenhaganists. A common answer is that before measured, the system is in “all states at once” or “smeared out into a wave”. This is not the copenhagen interpretation; it’s an objectively false description of quantum mechanics that I debunked in this article.

Another statement is that the object does not have a definite value before measured. This statement, though not directly incorrect, is going a step further and talks about the actual nature of a particle before measurement. The copenhagen interpretation only talks about probabilities before measurement (states are probabilistic), not the status of a particle having a certain quality before measurement. So if that stance is taken, then it is no longer the copenhagen interpretation. That stance is also very problematic: If I never observe an atom decay, does that mean that it does not having a decay status at all (ex. it has neither decayed nor not decayed)? This statement is an oxymoron. An object can either decay, or not decay. This is one of the basic principles of logic: a is not “not a” by definition. Some people decide to bite the bullet, and accept that oxymorons can still be true. This is a philosophy called “trivialism”, which is a topic for next time.

A common belief among Copenhaganists is that the measurement devices have to be outside the system. This makes sense, since the opposite would apply that systems can measure themselves, which would imply that systems always exist as having definite eigenvalues since they are constantly measuring themselves. It is this element of the Copenhagen interpretation that destroys itself from the inside. What I want to stress is that what follows is not personal interpretation, but actual undisputed fact about quantum mechanics. When we have 1 particle in our system, the wave function is a function of that one particle: it maps the locations/momenta/energies of that particles into another dimension (the axis of the wave function). In other words, it is a function that maps one input to an output. For 2 particles, the wave function is a function of 2 particles. For 3 particles, the wave function is a function of 3 particles. You get the idea. What I’m describing here is what is called “configuration space”, the space that contains all possible configurations of a system. We can go higher and higher and higher. Quantum mechanics implies that there is a wave function that is a function of every single particle in the universe. Again, this isn’t an assumption or interpretation. It is just quantum mechanics itself: The wave function if a function of n-particles in an n+1 dimensional configuration space. Just replace n to the number of all particles. So now we know that there is a wavefunction of the universe. What does this mean under the Copenhagen interpretation? Well the Copenhagen interpretation requires the measurer to be outside the system, but the system in question is the universe! This means that for the wave function to collapse, then someone outside the universe would have to measure the universe — but wouldn’t this person also be a part of the system? So you’d need another person outside everything else in the system to measure the person inside the system, and you get an infinite regress. Unless you believe that there is someone outside the universe that is collapsing wave functions left and right, then this is huge trouble for copenhaganists. Again, what we did was just normal quantum mechanics. We showed that the Copenhagen interpretation cannot even reconcile with this without postulating an infinite regress of measurers outside of our universe. Now since we actually do measure things inside the universe, this is a direct contradiction of what is implied by the Copenhagen interpretation, making the copenhagen interpretation (the way it is usually presented), false. Someone could try to save copenhagen by saying that systems can measure themselves, but that would mean that a system will have a definite value prior to us measuring it (since it had already measured itself), which would be a hidden-variable theory — something many copenhaganists are against: you can’t have your measurement device and eat it too.

Some people say, “we shouldn’t ask about what happens before it was measured since we aren’t measuring it.” This statement is self defeating. Quantum mechanics talks about probabilities before measurement, so with the logic, the copenhagen interpretation shouldn’t be talked about at all — no quantum mechanics should be talked about at all. But the stance itself is one on quantum mechanics, so it is a self defeating point. This is somewhat analogous to what happened to philosophical logical positivism.

Shut Up and Let Me Think

Some people simply don’t care: a usual statement they give is “well all the interpretations lead to the same results”. The people who genuinely believe this are a danger to the progression of physics. It is no secret that particle physics has been somewhat stagnant over recent years. And in my opinion, it is precisely because of people like this: the moderate. The moderate does not care about any deeper insight or intuition in what their mathematics describes. All they care about is performing a calculation. But physics isn’t just about performing calculations — it shouldn’t be just about calculations. Did Newton study the nature of light just to perform a calculation? Did Einstein theorize atoms just to perform a calculation? Did Georges Lemaitre, when he theorized the Big Bang, do so just to perform a calculation? The answer to all 3 of these, if you haven’t gotten it already, is no. These physicists did physics to better understand the world around them. They wanted to understand what made the universe tick. They wanted to fundamentally know the nature of material objects. All of these discoveries of course used calculations, and needed calculations, but calculations are what physicists use to guide them into understanding nature — they do not do calculations for the sake of calculations. One who only does physics for calculations is no different than a calculator; they do not need a job, because a calculator can do it for them — probably better. The reason as to why we do not have many “New Einsteins” or “New Diracs” is because many physicists of this modern age do not question the very meaning of the equations they write. They do not care to see beyond the math. They do not bother to ponder where the lure of physics is leading them — they only care about publishing that paper with some calculation. It was Galileo questioning the geocentric model that contributed to heliocentrism, it was Newton questioning the epicycles that gave us Newton’s laws of gravitation, it was Einstein questioning the works of Newton — looking deeper into the meaning behind the math — that gave us general relativity. It was even Einstein’s challenges towards the quantum mechanics orthodoxy that sparked even more interest in the subject, and an increase in much new exciting material like Bell’s Theorem and Entanglement that became something bigger than intended. All of this started with people looking beyond the math and asking: “what does this all really mean at a fundamental level?” If physics has lost people like that, then it has lost everything.

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