It’s time to admit quantum theory has reached a dead end • Hacker News Board

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

#211

Post by Beldin » Wed, Mar 09, 2022, 11:47 AM UTC

spookthesunset wrote: post #123

Iwan-Zotow wrote: post #95

Earlier quoted context omitted.

they are both called dark for a reason not very observable

Their effects are observable by way of their gravity.

That's very forgiving.

We have a model and weer have observations. The two don't match, so there is a problem with at least one (model or observations). MOND posits the problem is with the model and proposes refined models. These are refutable and indeed, counterevidence is often found.

Dark matter posits the problem is worth observations. Its solution is to propose a tiny particle that is basically invisible. For every situation, you then can invent an amount and a distribution of these tiny, invisible, undetectable particles to match observations and thereby substantiate your theory.

It's not really surprising that so far, folks have succeeded in inventing a distribution of undetectable clouds of particles, clouds weighing in at multiples of the solar system's combined mass.

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

#212

Post by adriand » Wed, Mar 09, 2022, 11:52 AM UTC

tluyben2 wrote: post #205

adriand wrote: post #115

Earlier quoted context omitted.

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…

We are human and prefer elegance, so enough will continue to try to unify models anyway. I don’t buy that we cannot understand nature but this model dependent realism is fine as a practical way of working until we do understand it.

> I don’t buy that we cannot understand nature

I don’t think anyone is saying that, but in pondering this issue, I remembered how in Spanish there are two verbs for “to know”, “saber” and “conocer”. That latter verb is often explained in English as “to be familiar with”. The usage makes the point best: you can “conocer” a person but cannot “saber” them. That is, you can be acquainted with someone but you cannot truly “know” them, no matter how close you are to them.

Think about it: how well do you know yourself? You live in your own head and yet you are probably surprised by some of your own reactions, or dismayed by your actions, or fearful of certain emotions. If you do not fully understand yourself then what does understanding nature even mean? I cannot inhabit the mind of my wife, let alone inhabit a photon.

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

#213

Post by Gigachad » Wed, Mar 09, 2022, 12:01 PM UTC

amusedcyclist wrote: post #163

fennecs wrote: 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. " . This should be stickied on every HN thread

Honestly the funniest comment I have ever seen on HN.

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

#214

Post by SinParadise » Wed, Mar 09, 2022, 12:45 PM UTC

michaelwilson wrote: post #131

shoyer wrote: 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…

How can you be a "former quantum physicist"? Did you somehow unlearn everything that made you a quantum physicist? Maybe you meant to say "formerly paid to be a quantum physicist"? :-)

>How can you be a "former quantum physicist"?

By disentangling himself with quantum physics. He was a quantum physicist, so I assume he knows how to do it.

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

#215

Post by sam_goody » Wed, Mar 09, 2022, 1:13 PM UTC

dang wrote: post #165

0x1062 wrote: post #113

Earlier quoted context omitted.

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

Please correct wrong information without shaming others. We're trying to avoid the online callout/shaming culture here. https://hn.algolia.com/?sort=byDate&type=comment&dateRange=a... https://news.ycombinator.com/newsguidelines.html

dang, you read every comment on every thread?

And you stay polite and interactive?!

Are you sure you are human?

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

#216

Post by gus_massa » Wed, Mar 09, 2022, 1:32 PM UTC

adriand wrote: post #115

shoyer wrote: 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…

>> Can light and matter be both particle and wave? Or neither? We don’t know.

But we know! The answer is neither.

Light and matter are weird things that is impossible to describe with usual language, but they can be described very precisely with math language. The problem is that the equations are too complicated and difficult to use.

They have been tested thoroughly, for example in particle accelerators but in experiments with very few things moving around. It's very difficult to use them when the experiment gets bigger.

In some cases, you can make some approximations and get almost the same result if instead of the full correct equations you use the wave equation. It's just an approximation. Light and matter are never waves, but in some case they can be approximated as waves.

In other cases, you can make some approximations and get almost the same result if instead of the full correct equations you use the particle equation. It's just an approximation. Light and matter are never particles, but in some case they can be approximated as particles.

And in other weird cases, bot approximations get very inaccurate predictions.

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

#217

Post by BeFlatXIII » Wed, Mar 09, 2022, 2:02 PM UTC

chii wrote: post #74

jiggawatts wrote: post #4

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…

I'm trying to remember which textbook or professor was the one who said that "shut up and calculate" was the Feynman interpretation of QM.

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

#218

Post by DebtDeflation » Wed, Mar 09, 2022, 2:45 PM UTC

adriand wrote: post #115

shoyer wrote: 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…

>And it has been shown to be right, every time.

So has GR. Yet the two theories seem to be utterly incompatible.

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

#219

Post by chasil » Wed, Mar 09, 2022, 2:54 PM UTC

jayd16 wrote: post #159

chasil wrote: post #89

Earlier quoted context omitted.

There are many practical applications of quantum mechanics. The one that I remember foremost is tunneling to (dis)charge the floating gates on flash memory transistors, but that just scratches the surface. "Flash memory chips found in USB drives use quantum tunneling to erase their memory cells." https://en.m.wikipedia.org/wiki/Applications_of_quantum_mech... This I did not know: "It even exists in the simple light s…

Is there something specific about oxidized metal that electrons need quantum tunneling to move through them? Why can't we just assume its normal conductivity?

Aluminum is extremely reactive, and the classic method of liberating this energy is through thermite reactions. Without the oxidation layer on aluminum, it would be an extremely hazardous substance.

"Breaking bad" covered this with an etch-a-sketch. Sometimes chemistry can be surprising.

https://en.wikipedia.org/wiki/Thermite

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

#220

Post by dekhn » Wed, Mar 09, 2022, 2:58 PM UTC

alar44 wrote: post #196

dekhn wrote: post #119

Earlier quoted context omitted.

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

Can you elaborate on why it's ill-posed?

proteins don't fold to their energy minimum, they typically "collapse" to an intermediate state and then sample many different states (kinetically), rather than adopting the absolute thermodynamic minimum. In many proteins, the structure snapshot doesn't even correspond to a functionally active protein. The "protein folding problem is NP-hard is an entirely inaccurate view of the biophysics of folding", and if solved, would not address any useful question about folding.

What DeepMind solved was a far simpler problem: reproduce the structures that get produced by some experimental method. That's a well posed problem but ultimately a less interesting one, even if it's immediately "useful".