The Zen anti-interpretation of quantum mechanics (2021) • Hacker News Board

Re: The Zen anti-interpretation of quantum mechanics (2021)

#61

Post by kahnclusions » Wed, Dec 28, 2022, 1:35 AM UTC

goatlover wrote: post #31

layer8 wrote: post #29

Earlier quoted context omitted.

My understanding is that this is just the law of large numbers. Most branches match the mathematical probabilities very closely, and hence that’s what we observe. Yes, people on one of the rare branches where things behave differently wouldn’t observe that, but we simply happen to not be on one of those rare branches.

So you’re endorsing Many Worlds with an appeal to the anthropic principle. That’s fine, but you do have to assume MWI is the true interpretation of the mathematical formalism.

I’m not a fan of Many Worlds. Communication or even detection of the split universes is impossible, which means it is impossible to measure. And science requires measurement to confirm our theories. Which means the MWI is equivalent to a simpler interpretation that doesn’t require split universes.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#62

Post by blamestross » Wed, Dec 28, 2022, 1:38 AM UTC

blamestross wrote: post #59

dilap wrote: post #14

Earlier quoted context omitted.

Well, do you think there is a truth, understandable by humans, about the nature of the universe? If you think there is, what better guide than our best theories of physics so far? So of course what the nature of the universe is doesn't really affect anything, on a physical level, but our sense of what happens after we're gone does in fact change our behaviors. E.g. Most people contemplate with more horror the possibi…

But it's not you. And the idea of every possiblity playing out is a lot less exciting than idealized. The Alter where you both exist and is better is not actually guaranteed to exist. In fact basically all them are guaranteed to essentially identical. Quantum splits at a macro level would basically only happen now that we have quantum random number generators to make decisions based on and I doubt that will add up to…

You are welcome to whatever religion you need to settle your existential emotional needs, but don't expect the science to play out in a direction that matches your fantasy.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#63

Post by pdonis » Wed, Dec 28, 2022, 1:42 AM UTC

_0w8t wrote: post #15

The article misses that we do not know how classical world that we perceive arises. Ultimately according to QM the whole universe is just single wave function with no probabilities. But this contradicts our experience of the classical world including that we measure probabilities. So we need to explain that to avoid various very ad-hock notions of classical measurement device and similar routes. There are attempts to…

> There are attempts to explain the classical world using a notion of decoherence, but that have problems with little progress in the last, say, 20 years to address them.

What problems? Note that Aaronson, in the article (as well as a number of commenters in the comments) gives decoherence as precisely the answer to the issue you raise.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#64

Post by pdonis » Wed, Dec 28, 2022, 1:42 AM UTC

_0w8t wrote: post #15

The article misses that we do not know how classical world that we perceive arises. Ultimately according to QM the whole universe is just single wave function with no probabilities. But this contradicts our experience of the classical world including that we measure probabilities. So we need to explain that to avoid various very ad-hock notions of classical measurement device and similar routes. There are attempts to…

> the new take is that the classical notion that the state of a system can be fully described by its properties at some moment in time is wrong. One also needs to know some information about future to fully describe evolution of the system.

Do you have any references that give more details on this?

Re: The Zen anti-interpretation of quantum mechanics (2021)

#65

Post by pdonis » Wed, Dec 28, 2022, 1:44 AM UTC

_0w8t wrote: post #27

FeepingCreature wrote: post #17

Earlier quoted context omitted.

In the single wavefunction, beings who perceive classical reality arise from mere wavefunction mathematics. How does this not answer the question? Once you can locate yourself in a system, the system is adequate as a physical theory of your phenomenological state.

This does not explain how a classical observer gets probabilities that are precisely measured. In universe-as-a-wave-function there are no probabilities. So how exactly do they arise and what they mean?

> In universe-as-a-wave-function there are no probabilities.

There are probability amplitudes in the universal wave function, and those are complex square roots of probabilities.

It is true that deriving the Born Rule purely from the unitary dynamics of the wave function is an unsolved problem. This is discussed a fair bit in the comments to Aaronson's article.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#66

Post by stubish » Wed, Dec 28, 2022, 1:45 AM UTC

coldtea wrote: post #51

> I hold that all interpretations of QM are just crutches that are better or worse at helping you along to the Zen realization that QM is what it is and doesn’t need an interpretation. As Sidney Coleman famously argued, what needs reinterpretation is not QM itself, but all our pre-quantum philosophical baggage—the baggage that leads us to demand, for example, that a wavefunction |ψ⟩ either be “real” like a stubbed to…

He argues this further down as real/unreal being a bad dichotomy.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#67

Post by dools » Wed, Dec 28, 2022, 1:49 AM UTC

sampo wrote: post #18

dools wrote: post #16

What I don't get is why people are more concerned with how Qauntum Mechanics works than they are with the way in which, for example, electro magenetic waves travel in a vacuum. Like we can "physically" understand how sound travels, and we can "visualise" that as a "mechanism" right? But we have no similar way of "physicalising" the way in which light travels, but no-one seems to have any trouble accepting that. Quant…

Quantum mechanics has wave function collapse, which is both essential in applying the theory to explain any physical situation, and at the same time not described by the theory. Other than "and then it collapses". Classical theories don't have this problem.

The whole “wave function collapse” thing as far as I understand is simply the result of any measurement involving entanglement. When you measure something by any means you create an entanglement that cancels out the term in the equation that produces “wave like” behaviour.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#68

Post by dools » Wed, Dec 28, 2022, 1:52 AM UTC

krastanov wrote: post #20

dools wrote: post #16

What I don't get is why people are more concerned with how Qauntum Mechanics works than they are with the way in which, for example, electro magenetic waves travel in a vacuum. Like we can "physically" understand how sound travels, and we can "visualise" that as a "mechanism" right? But we have no similar way of "physicalising" the way in which light travels, but no-one seems to have any trouble accepting that. Quant…

For many people the statement "electromagnetic fields exist as a (fundamental) building block of Nature" is just as reasonable as "atoms exist as a (fundamental) building block of Nature". The word "fundamental" is not particularly important, I am keeping it for historical reasons. You are perfectly comfortable with the existence of atoms (given your comments about understanding sound waves), presumably because you k…

> what in your personal aesthetic tastes is making atoms more palatable?

It’s pretty easy for me to imagine things bumping into each other because I see that happening all around me

Re: The Zen anti-interpretation of quantum mechanics (2021)

#69

Post by DiogenesKynikos » Wed, Dec 28, 2022, 1:53 AM UTC

Jensson wrote: post #49

layer8 wrote: post #44

Earlier quoted context omitted.

The perceived wave function collapse is explained by decoherence. There is no extra “split” that happens. “World” is just a term referring to the parts of the universal wave function that are entangled with each other. As to “exactly when the universe will split into many worlds”, it happens zillions of times per second pretty much everywhere. It’s even not clear whether the branching is a discrete and countable occu…

So when does decoherence happen? Provide a formula for it. That is what people struggle with in quantum mechanics, MWI just deflects the question. Without a formula for when this phenomena happens any "interpretation" is just nonsense, except as a tool to get towards that formula.

The mathematical framework for modeling decoherence involves coupling an isolated system to a thermal bath, described by a density matrix.

Decoherence is a phenomenon that's been studied mathematically and experimentally, not simply an interpretation or hand-waving.

Re: The Zen anti-interpretation of quantum mechanics (2021)

#70

Post by gaze » Wed, Dec 28, 2022, 1:53 AM UTC

_0w8t wrote: post #15

The article misses that we do not know how classical world that we perceive arises. Ultimately according to QM the whole universe is just single wave function with no probabilities. But this contradicts our experience of the classical world including that we measure probabilities. So we need to explain that to avoid various very ad-hock notions of classical measurement device and similar routes. There are attempts to…

> just single wave function with no probabilities

this is definitely not true and contradicts relativity. (Type-III Von Neumann algebras have no pure states.)