I guess I’ve always been confused by the Many Worlds Interpretation of Quantum Physics and the fact that it’s taken seriously. Like is there any proof at all that universes outside of our own exist?
I admit that I might be dumb, but, how does one look at atoms and say “My God! There must be many worlds than just our one?”
I just never understood how Many Worlds Interpretation was valid, with my, admittedly limited understanding, it just seemed to be a wild guess no more strange than a lot things we consider too outlandish to humor.
Yes, but, again, this is only because you have imperfect information about the underlying physical system. The array of possibilities presented by classical statistics are strictly epistemic; the actual real state of the system you’re analyzing is always definitive and determinate.
And very, very importantly, this is not that case in quantum physics. The indeterminacy of state in a super position is not just the result of imperfect information; it is a fundamental part of the underlying system. It is not the case that, in the double slit experiment, the electron only travels through one slit, and we just don’t know which one. It really really does travel through both. This is fundamentally different from classical mechanics.
Look, if you want to try and argue that quantum physics isn’t physics, I won’t stop you, but you’d better have an extraordinary argument, because this is an extraordinary claim. One that rejects the last century of scientific consensus. If you can demonstrate that quantum mechanics is just a different statistical model of classical physics, it would be a revolution in science.
That’s correct, and MWI doesn’t argue otherwise. The important part isn’t just that these states are possible, it’s that they have real physical existence.
You are glossing over my point. I’ll try to put it as concretely as I can think of:
Assume for the sake of argument that there is a process in an otherwise classical physical system that is truly nondeterministic, meaning there is randomness that isn’t due to any hidden variable or otherwise incomplete knowledge of the state of the system.
When describing such a system, you will run into the same dilemma of either needing a “wavefunction collapse” or “many worlds” interpretation of your statistics.
And yet this model is not quantum. It is a classical nondeterministic model.
My point being, it’s the existence of true nondeterminism that leads to the “many worlds” idea, not the other strange properties of quantum mechanics.
I really, genuinely, think this is not a controversial take. The idea that quantum mechanics is more of a rethinking of statistics than physics comes from my own personal experience studying quantum physics. Most of the time, you take the classical Newtonian mechanics equations (sometimes including “corrections” for relativity), and treat them with the “quantum mechanics” version of statistics, and out pops all the important things you’d like to model, like how electrons arrange into orbitals in an atom. The results of slit/entanglement/bell experiments depend on having an object that obeys quantum statistics, but it can be a wide variety of objects with vastly different physical properties and behaviors (e.g. slit experiments have been done with both photons and electrons).
I don’t think there is any reason to believe the “other worlds” needed to analyze quantum systems “physically exist” to any meaningful extent. It’s the same as considering all possible outcomes of a classical truly random event (if you assume there exists true nondeterminism, not simply a lack of complete information).
I promise I’m not doing it deliberately.
Yes, I would agree with that if we’re using “wave function collapse” to refer to any truly probabilistic mechanism in a general sense (as, strictly speaking you could have a non-deterministic mechanics without wave functions at all).
But I note the important fact that you don’t need both.
Well no, it’s the existence of true non-determinism without any form of wave function collapse.
Well if that’s the case, with all due respect, I think you need to study quantum physics more. Because trying to overturn a century of scientific consensus is definitely controversial, at best.
How, specifically, are you modeling the double slit experiment using only Newtonian Mechanics? How about quantum tunneling?
Are claiming that super positions don’t actually exist at all? Because, again, you’d better have a solid argument for such a radical claim.
Is it? Hard to say when we’re talking about something that doesn’t actually exist.
I don’t think what I’m suggesting is “trying to overturn a century of scientific consensus”. It’s a mildly different interpretation of the same math, that doesn’t require many physical worlds. It’s also not that uncommon. The “many worlds” idea is not scientific consensus. Go read about interpretations of quantum mechanics from sources other than Sean Carroll.
Both the double slit experiments and quantum tunneling emerge when you apply quantum statistics to any point particle following Newtonian mechanics.
Superpositions are a mathematical tool for describing the statistics of potential measurements.
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Here’s an interesting example:
The Bell test about entanglement is one of the best-known proofs that quantum mechanics can’t be explained using classical statistics.
The Bell test is an analysis of the correlation between two entangled particles.
However, that correlation is only notable because we are analyzing the evolution of both particles.
If we analyze one particle, alone, we wouldn’t be able to determine if it is entangled with any other particles (and we wouldn’t be able to model it without the need for quantum mechanics).
In other words, you only need the “other worlds” when you are analyzing a system and trying to predict its behavior. You can completely ignore all information or “other worlds” external to the system you are studying.
That seems to demonstrate the opposite of your argument though, because the other particle does still exist even if you don’t consider it.