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It’s time to admit quantum theory has reached a dead end

nautil.us

111–120 of 236 posts

Re: It’s time to admit quantum theory has reached a dead end

#111
I come to HN to learn new things in fields I know little about, like tech and computers, I always find the comments to be authoritative and interesting.

However, whenever I read the comments on any subject I happen to know something about, like physics, they are always completely nonsense from people who clearly have absolutely not even the smallest amount of experience in the area they are talking about. The worst part is, all these comments sound extremely authoritative, if I didn't know any better I would have believed they were experts.

This makes me very worried about the Gell-Mann Amnesia affect. I'm very worried that all the comments I've been reading on here about tech and computer topics are also just from larpers who are pretending to be experts but actually don't know anything.

Re: It’s time to admit quantum theory has reached a dead end

#112
post #94
post #74

Earlier quoted context omitted.

> because approaches like this often have virtually no explanatory power. the famous feynman have produced a response to this train of thought - usually from the laymen - where they demand an "explanatory theory". The answer is usually "don't know"; why gravity work the way it does? - don't know, but we can calculate orbits to great precision; why does photons or electrons travel the way it does? - don't know, but we…

Feynman must have driven his wife mad. "Honey did you take the garbage out?" "When you say garbage, have you considered if garbage can even really exist?"

In analogy to this discussion, it'd be the opposite, actually -- situational Feynman would be the person who knew he could practically gather specific unwanted matter into a bin or sack and take it out to the collection bin for most practical volumes, while situational wife would be the person asking for an explanation "but how do you know that what you have taken out is the garbage and that it has in fact been removed"?

Still, it's fun to play with this idea via figures who are a little more philosophically rarified as it were:

https://www.tiktok.com/@davecolumbo/video/706085573209017886...

Re: It’s time to admit quantum theory has reached a dead end

#113

I come to HN to learn new things in fields I know little about, like tech and computers, I always find the comments to be authoritative and interesting. However, whenever I read the comments on any subject I happen to know something about, like physics, they are always completely nonsense from people who clearly have absolutely not even the smallest amount of experience in the area they are talking about. The worst p…

name and shame, so those of us non-experts can spot the bad comments.

Re: It’s time to admit quantum theory has reached a dead end

#114
post #74

Earlier quoted context omitted.

To me, this always felt like programmers excusing abhorrent code with "but it works". Quantum theory isn't. It's not a single, cohesive, consistent theory.[1] There is no recipe you can apply, it's just a bunch of guessworks and heuristics that happen to produce the numerically correct equations if you keep trying long enough. This isn't secret or some sort of external criticism, you'll find this front-and-centre in…

> because approaches like this often have virtually no explanatory power. the famous feynman have produced a response to this train of thought - usually from the laymen - where they demand an "explanatory theory". The answer is usually "don't know"; why gravity work the way it does? - don't know, but we can calculate orbits to great precision; why does photons or electrons travel the way it does? - don't know, but we…

You could say that the "explanation" of inertia is that which preserves the symmetry of space translations under Noether's theorem. But that doesn't tell a physicist any more than they already knew, and it tells a layman even less.

Re: It’s time to admit quantum theory has reached a dead end

#115
post #73

As former quantum physicist, I find it little troubling to read "quantum theory has reached a dead end" in specific reference to the interpretation of quantum mechanics. Most quantum physicists could not care less about how quantum mechanics is interpreted when it makes highly accurate quantitative predictions, and there are still plenty of interesting open problems for quantum theory (e.g., related to the practical…

I read somewhere that quantum mechanics is the most tested of all scientific theories. And it has been shown to be right, every time.

Hawking espoused this idea he called “model dependent realism”. The idea is that every human understanding of reality is model-dependent, that is, it is not “reality” that we truly understand (we can’t) but rather in every case we have some model of reality that is useful in particular situations. For instance, we know that Newtonian physics are not “real” but they are perfectly accurate in certain situations. So they are not “wrong” when they are used in those situations, in fact, they are right.

The author of the article writes, “While Einstein won a Nobel Prize for proving that light is composed of particles that we call photons, Schrödinger’s equation characterizes light and indeed everything else as wave-like radiation. Can light and matter be both particle and wave? Or neither? We don’t know.”

In model dependent realism, we can ignore this apparent contradiction. In some situations the model of light as a particle is the most useful, and in others, the model where it is a wave is the most useful. We have to accept that it is not “really” either of these models, but that no matter what we do, any model we come up with for it will still just be a model.

Re: It’s time to admit quantum theory has reached a dead end

#116
I think a 100 years of now 17-decimal accuracy is fine.

Maybe we do need a Copernican revolution. But how many areas of physics and science can we say that? A lot.

I think for sure the idea of measurement as a passive activity revealing pre existing values is gone though. No matter what happens. How long was that a paradigm?

Re: It’s time to admit quantum theory has reached a dead end

#117

Earlier quoted context omitted.

There are 19 free parameters in the Standard Model. These include such values as the mass of various particles (electron, muon, tau, six quarks, Higgs), Higgs vacuum expectation value, the strength of several interactions, and the mixing angles and phases for certain interactions. You can rearrange some of the parameters so that they're not free, and redefine each of these in terms of some other related parameter — y…

One theory, which I find quite plausible, is that there are many universes, all of which have variations on these constants. And the reason our universe is the way it is, is because we are here to observe it - given that most other configurations of these constants wouldn’t support life (the strong anthropic principle).

It's one that comes up, but first consider that it's not fundamentally clear to the layman that these values are actually completely "free parameters".

Imagine, if you will, benchmarking some unknown CPU, and determining that the fused multiply-add operation takes, idk, 17 times as long to execute as an increment operation. We might postulate that there other CPUs out there where it takes a different amount of time — arbitrary amounts of time! Alternatively, we might gain knowledge of the underlying CPU architecture and understand that fused multiply-add is implemented with a certain set of transistors, and that it's fundamentally more complex, though there's room for some variability based on the specific implementation. In such a world this "free parameter" is set as it is for a very specific reason: a transistor arrangement.

We have limited visibility into what's actually happening "underneath" our laws of physics. Some of the values we see could be truly arbitrary. Some of them might actually be controlled by some other field and change over time (though we haven't seen evidence of that so it seems less likely). Some of them could be a deeper artifact of the way the universe works.

If you look at things like string theory, which do try to describe in more detail and dial down the free parameters to just one ("length of the fundamental string" more or less) we are left with something that's frustratingly nonspecific until you locate a more-specific solution within the broader string-theory solution space and call it "the laws of physics." That specific location might indeed seem quite arbitrary; the question might then become, what relation does this hundreds-of-dimensional solution space have with our concepts of physical reality? And can other areas of that landscape be probed in any way meaningful to our experience of physics?

Re: It’s time to admit quantum theory has reached a dead end

#118

Tl;Dr: quantum physicist in the midst of existential crisis articulating his dread.

It seems weird to me that somebody could get a physics PhD without a deep enough understanding of the philosophy of science to

1) understand why science avoids these 'what, really, is X' questions in favor of 'how does X work'

2) circumvent this existential crisis

Re: It’s time to admit quantum theory has reached a dead end

#119
post #85
post #68

Earlier quoted context omitted.

"We know the forces of all the atoms that act on each other, what is the mystery at this point other than calculating it is hard?" might be true, but it's computationally intractable and even if you did find a way around it you'd just learn that your force field was inaccurate, or that proteins don't actually fold to their energy minimum. Not just hard, but NP-hard. In fact, the "protein folding problem is NP hard" i…

Right, my point is that it's as solved as it can really be as far as human understanding is concerned. There are too many variables at play to have any sort of elegant solution like Ohm's law or calculating an orbit. The best we can do is find different/more efficient/novel methods to calculate it. Am I wrong?

The problem is ill-posed, not that we lack a solution.

Re: It’s time to admit quantum theory has reached a dead end

#120
post #64

Amusing to see all the pessimistic comments form programmers who have zero understanding beyond high school maths thinking somehow there is a magic solution to all the problems in physics like you can just refactor everything. Quantum field theory is definitely not stuck in the 1920s. Modern physics has a lot more going on than 19th century mathematics. We understand quite a lot about the mathematical structure under…

Don’t use your intuition developed from grinding out web crap to try and reason about the forefront of human knowledge. Have you tried front end web frameworks recently? String theory has nothing on them.

Eventually there will be so many JavaScript libraries and frameworks that they will collapse in upon themselves and create a black hole.
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