question about quantum mechanics

[Paulus Amadeus]

Here is a question about quantum mechanics, for Leo or for anyone who knows the answer:

If quantum mechanics says that a particle collapses when it is observed, but actually there is no observer or observing that has ever hapenned, then what does this collapse of the wave function mean? Is it that infinite possibility or nothing has materialised into a temporary finite form?

 

[crab12]

The collapse of the wave function is just a convenient mathematical model that physicists use in calculations. You are interpreting a mathematical model in a literal way and coming up with these assumptions. There's also Bohm's interpretation of quantum mechanics which is deterministic. No "infinite possibility" or anything. And it gives the correct answers too in many cases. But it is inconvenient to use in calculations so physicists prefer to use the wave function. Which mathematical model describes reality more accurately? Nobody knows. But do you really want to base your philosophy on the literal interpretation of what some clever mathematician came up with on paper?

[Paulus Amadeus]

I’m trying to understand what the quantum mechanics model means in light of there not really being a perceiver. I know the real pudding is in the direct experiences, and not in the theory, but right now I just want to understand it.

if everything is deterministic according to Bohm, then why do all the experiments point to probabilistic wavefunctions?

and what enforces that the chance is really small that you’ll measure to electrons in the same place in an experiment? The traditional answer is that they both have negative charge, and thus repel eachother. but that doesn’t make sense anymore because all there is is perceptions! There is no negative charge, nor are there electrons. Yet thinking of it like there is negative charge and that there are electrons, gives you huge power to predict what will happen. This all seems very strange to me right now!

[crab12]

2 hours ago, Paulus Amadeus said:

if everything is deterministic according to Bohm, then why do all the experiments point to probabilistic wavefunctions?

Can you bring some examples where Bohm's model doesn't hold up? I would be interested in that.

edit: I googled a bit. Bohm's pilot wave holds up to the classical double slit experiment, even when a single photon or electron is fired at a time. Pilot wave does struggle with quantum entanglement and delayed choice quantum eraser experiment but it still doesn't rule out a deterministic model.

Quote

I’m trying to understand what the quantum mechanics model means in light of there not really being a perceiver

Wave function tells us that if there is no observer then it is a wave of probability. The wave contains all possibilities. And when the observer looks it chooses one randomly (based on % of probability). And according to other models parallel universes area created during the moment of collapse - one for each possible choice. You have probably heard of the Schrödinger's cat meme. If you interpret the model literally then while nobody looks into the box then the cat must be both alive and dead because the probability wave contains all possibilities while not collapsed. This thought experiment was made up to demonstrate how silly classical interpretation of quantum mechanics is. But maybe that's how reality actually is, who knows.

Bohm's model tells us that the wave / particle already has a set path whether there is an observer or not. It doesn't choose anything the moment the observer looks. The problem is quantum world is so small we can't look at it directly. Say you flip a coin and hide it under your palm. Do you think the coin is both heads and tails at the same time and when you take a peek the coin chooses one randomly? Maybe this is exactly what that pesky coin does, the bugger! Or maybe the universe splits into 2 the moment you peek, so there's one of you who saw heads and another who saw tails. Or maybe it just lands on one side but you just can't see it because it is under your palm and you are just imagining it to yourself that the coin is a wave of probability until you take a look or that the universe splits the moment you look. Imagine that! Crazy, right? Anyway this is a giant mental masturbation arguing which model is the correct one. Both explanations of reality can be viewed as correct.

You don't have to go as far as quantum mechanics. Why does e=0.5*m(v*v) describe how a car or a bowling ball behaves in normal everyday situation? There are no cars or bowling balls or speed or mass, it's all just perception that we arbitrarily categorize in these terms.

Edited October 13, 2019 by crab12

[Paulus Amadeus]

I see, yeah if you would mean with predetermined that every possible solution happens, and the universe just keeps splitting into new possibilities, then yes, I’m the big picture sense there is no probability any more. Although you could still calculate the probility for in which of the worlds you end up! There might be a 20% chance that you end up in the world where the electron is seen between point A and B.

for your second point: that’s exactly what I want to know! Why does e=0,5*mv^2 hold up if there is no stuff behind the scenes! What makes everything behave in such a way that this formula seems to be true!?

[crab12]

The harsh truth is: we don't know. Quantum physicists have come up with those 2 (or 3 if you count multiverse as seperate) explanations. But in the end, reality is what it is. It just is. That satisfies me, but you can seek further is you want to. But what answer could possibly satisfy you? Even if the scientists tell us that, yup we have now 100%, beyond the shadow of a doubt, confirmed how reality actually works, it is still going to be only a collection of thoughts in our mind trying to rationalize our perception / reality.

Edited October 14, 2019 by crab12

[outlandish]

What is Real? by Adam Becker is a really good book on the history and politics of quantum physics and it's interpretation. I recommend anyone with an interest in the area to check it out. It really puts the science around quantum physics into context and perspective.

I like the quantum multiverse interpretation, it's the only one that makes sense to me. The Copenhagen interpretation has a problem where you have to find some boundary between quantum scale and normal scale, which seems artificial, and you have to kludge in the observer thing. Bohm's wave guide interpretation seems contrived, but I can't really remember the specifics of what I didn't like about it off hand... 

It's very mysterious, but I like what you had to say @crab12. Even if we rationally knew 100% what's going on there, would our experience of existence be any different? I think Bohr and the Copenhagen people are/were satisfied with "it's weird and here's the math", maybe the quantum level really just is the limit of what is knowable about reality.