Testable proposals for the measurement problem

In a previous post, I made the statement: “Currently, there are no known experimental conditions that can distinguish between different interpretations of quantum mechanics.” Well, that is not exactly true. Perhaps one can argue that no experiment has yet been performed that conclusively ruled out or confirmed any of the interpretations of quantum mechanics. But, the fact is that recently, there has been some experimentally testable proposals. Still, I’m not holding my breath.

Recently, seeing one such proposal, I remembered that I also knew about another testable proposal made by Lajos Diósi and Roger Penrose. The reason I forgot about that is probably because it seems to have some serious problems. At some point, during a conversation I had with Lajos, I told him I have a stupid question to ask him: does quantum collapse travel at the speed of light? His response was: that is not a stupid question. So, then I concluded that it is not something that any of the existing collapse models can handle correctly. In fact, I don’t think any such model will ever be able to handle it in a satisfactory manner.

Thinking back to those discussions and the other bits and pieces I’ve read about the measurement problem, I tend to reconfirm my conviction that the simplest interpretation of quantum mechanics (and therefore the one most likely to be correct) is the so-called Many Worlds interpretation of quantum mechanics. However, the more I think about it, the more I believe that “many worlds” is a misnomer. It is not about many worlds or many universes that are constantly branching off to become disjoint universes.

Perhaps one can instead call it the “multiple reality” interpretation. But how would multiple realities be different from “many worlds”? That fact is that these realities are not disjoint, but form part of the unitary whole of a single universe. These realities can be combined into arbitrary superpositions. What more, these realities are not branching of to produce more realities. The number of realities remains the same for all time. (There are actually an infinite number of them, but the cardinality of the set remains the same.) The interactions merely change the relative complex probability amplitudes of all the realities. 

Anyway, just thought I should clear this up. I don’t see myself ever writing publication on this topic.

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The state of physics

One of the quirky things about me is that I don’t believe things I don’t understand. As a result of that, I’ve had a long turbulent relationship with the notion of black holes. See the thing is, for the longest time, I couldn’t understand how an event horizon can form if the time becomes frozen when the infalling matter approaches the point where the event horizon should form.

While I was grappling with this existential aspect of black holes, the rest of the world happily proceeded to invent wormholes, Hawking radiation, singularities, and eventually the information paradox. Together with event horizons, none of these ideas have entered the realm of establish scientific fact, which requires observational confirmation.

Eventually, I read somewhere that the reason an event horizon can form even though the time becomes frozen is because the location for the event horizon with and without this additional matter implies that the matter would past the point where a new event horizon would form in finite time. So, now I understand it and I believe that event horizons can form. But we are not done yet. What about the interior beyond the event horizon? It is still frozen in time. Where does the singularity come from? I still don’t believe that part, perhaps because I still don’t fully understand it.

In all this, the importance of the scientific method should be emphasized. Even if I don’t understand something, I would believe it if it has been observed. While event horizons may be difficult to observe directly, the singularity inside the black hole is completely impossible to observe. For that reason, it can never be part of our scientific understanding.

This year, the Nobel committee announced that the Nobel prize is award for work on black holes. Half of it goes to two people that inferred the existence of a massive black hole at the centre of the milky way galaxy based on the orbits of stars close to the centre. This work is based on scientific observation and therefore satisfies the requirements imposed by the scientific method.

The other half of the Nobel prize is awarded to Sir Roger Penrose “for the discovery that black hole formation is a robust prediction of the general theory of relativity.” If I understand correctly, the award is based on the Penrose–Hawking singularity theorems. (Hawking did not share the Nobel prize because he passed away.) So what is meant by “a robust prediction” here?

Sir Roger Penrose

Sir Roger Penrose is a formidable person. During his lifetime, he has produced a remarkable collection of ideas that range over diverse fields. The originality and complexity of these ideas give evidence to Penrose’s uniquely creative intellect. However, these ideas are of a mathematical nature and they show very clearly that Penrose is primarily a mathematician. Many of these ideas have never been confirmed by scientific observations. This lack of scientific confirmation includes the work on singularities in black holes for obvious reasons explained above.

It now brings me to the question, why would the Nobel committee decide to award a prize for “a robust prediction,” instead of something that has been confirmed in a scientific manner? The answer is probably related to the current state of physics. If we look at the work that was awarded recent Nobel prizes in physics, one can see that there must a problem. The problem is that progress in fundamental physics is slowing down or has come to a complete stop. There simply is nothing else to be awarded a physics Nobel prize anymore.

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The problem with the measurement problem

It is not really a topic I want to discuss. In fact, I don’t think it is worthy of including under my Demystifying Quantum Mechanics series. However, since even physicists don’t seem to get it, it is necessary to clarify a few things.

So the argument seems to go that even of one were to consider a completely mixed quantum states with equal probabilities for different outcomes then a measure would convert this mixed state into one with only one outcome and zero for all other outcomes. This transformation is then interpreted as a quantum collapse and the fact that this process is not understood is called the measurement problem.

The problem with this interpretation of the situation is just that: it is an interpretation. So it falls under the general topic of interpretations of quantum mechanics. Currently, there are no known experimental conditions that can distinguish between different interpretations of quantum mechanics. As such it is not physics, because it is not science. It falls under philosophy. As a result, it would not be possible to solve the so-called measurement problem.

Just in case you are wondering whether this measurement scenario can be interpreted in any other way that does not involve collapse, the answer is yes. The obvious alternative is the Many World interpretations. In terms of that interpretation the mixed quantum state describes the different probabilities for all the different world in which measurement are to be performed. If one would restrict the quantum state to any one of these worlds (or realities) then it would have 100% probability for a specific outcome even before the measurement is performed. Hence, not collapse and no measurement problem.

So, yes indeed, the measurement problem is a pseudo-problem. It is not one that can (or need to be) solved in physics.

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Garlic and tomatoes

It cannot be said, with any stretch of the imagination, that I am afflicted with green fingers. In fact, many years ago when I told my friends about my gardening attempts, they would burst out laughing. So, for years, prior to being presented with the opportunity to employ a gardener, I would think of that place outside my backdoor as a tortured garden. It is challenging to have a nice garden in a water scarce country.

So, why I decided to venture into this direction again, I don’t know. But it is fun, sort of.

I decided to harvest the pips of an overripe tomato and put them in some soil. Amazingly enough, they germinated. As they got bigger, I transferred them to individual containers. Now they are starting to become big enough to put into a big pot where they can stay until they would (hopefully) produce tomatoes.

I also had a garlic pod that started to look a bit sad. Although I like garlic in my food, I don’t seem to use it at a fast enough rate. So the garlic does not last. The thing made it quite clear that it wishes to burst forth and … grow. So, I relented and planted the thing. Now you wouldn’t believe just how must life there is in that pod. It sprouted leaves, all bunched together, like there’s no tomorrow. Soon I’ll have to find a bigger container and separate the thing into different pods, I guess.

Anyway, it would be a proud day, some time in the hopefully not too distant future, if I can harvest my own tomatoes and garlic and prepare some dish with them. It would mark a personal triumph, but I guess I still would not tell my friends, lest they laugh at me again.

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Hermitian existence

South Africa has the dubious honour to be among the top ten countries in the world with the highest number of confirmed COVID-19 cases. Of these ten countries, South Africa has the highest rate of daily increase in cases, over 4%.

Why? Perhaps one can blame the existing culture of disdain for the government’s regulations. It doesn’t matter that the government is trying to impose regulations to curb the spread of the virus. People ignore it and try to life as they like. One can understand why the government has lost it credibility looking at the recent history of corruption, state capture, and general incompetence.

I’m a scientist and not a politician. So I don’t want to discuss politics. Any reasonable person that sees the statistics can decide for themselves that it makes sense to isolate oneself as far as possible. So, what the government is trying to do makes sense, even if it is sometimes a bit too little too late.

The bottom line is, here I’m sitting in my house like a hermit. The hermitic existence is not so bad. The idea of living as a hermit has been part of western culture for centuries. It is intend to improve spiritual growth. I guess, it very much depends on the kind of person that you are. Not everybody can handle such seclusion for an extended period of time.

Charles Hermite
Charles Hermite

As a theoretical physicist, one can perhaps take some inspiration from Charles Hermite, whose last name sounds like hermit. He was a French mathematician who made significant contributions that are still widely used in quantum mechanics, among other fields. For example, a Hermitian operator is one that equals it Hermitian adjoint. It always has real eigenvalues. All physical states are represented by Hermitian operators

It this sound like twaddle to you. Don’t worry. What I’m try to get at is that if you currently also experience a “Hermitian “existence (as opposed a hermetic existence), then you can know that you are a real (valued) physical person. (Haha – just kidding. Perhaps only the mathematically inclined would find that funny.)

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