Einstein-Bohr debate settled once and for all

by nsoonhui • 4 years ago

138 102 4 years ago

superb-owl2• 4 years ago

This line of reasoning could probably be applied to any scientific debate between two greats. Both experts are trying to qualitatively describe how the current model coheres or disagrees with their internal models of reality. Since both have very good (but also very different) internal models, you get two accurate impressions of the bigger picture, however vague or incomplete.

It's like the parable of the five blind men who encounter an elephant.

layer8• 4 years ago

It's like the parable of the five blind men who encounter an elephant.

It’s not like that, because Bohr and Einstein looked at the same empirical evidence.

superb-owl2• 4 years ago

They didn't though! They had access to the same body of work, but their individual biases, tastes, and intuitions would have skewed both which research they paid attention to, and how much credence they gave it.

This is essentially my point. We all have access to the same set of data, but we all look at it a little differently.

zmgsabst2• 4 years ago

In 2022, quantum mechanics does still seem to be a final answer—not an approximation to anything deeper as Einstein hoped.

Things that have big question marks, related to this debate:

- how do we mesh quantum with gravity?

- why do tangles cause quasiparticles?

- does tangling rescue geons?

One theory is that quantum mechanics is an approximation of tangles in a higher dimensional space when viewed as pseudoknots, in the style of AdS/CFT.

tbrownaw• 4 years ago

I found a page for geons, and I think I know what quasiparticles are, but what's a tangle in this context?

zmgsabst2• 4 years ago

A concept from knot theory.

https://en.wikipedia.org/wiki/Tangle_(mathematics)

Which impacts dynamics/effects in various systems.

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

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

https://www.nature.com/articles/nphys1504

dataflow7• 4 years ago

Something I never understood: if we take the Big Bang theory at face value, shouldn't we believe everything is entangled together? And thus is there any to think superdeterminism isn't the ultimate explanation?

officialjunk• 4 years ago

entanglement is not permanent; decoherence.

dataflow7• 4 years ago

Doesn't decoherence just mean entanglement with other particles increases as the particle interacts with its environment? I never understood it to mean that the "total entanglement" (loosely speaking) will decrease somehow. Rather, I thought it means that mutual entanglement between N particles starts involving N + 1 particles, N + 2, etc. until it grows large and N just becomes insignificant.

beloch• 4 years ago

The famous EPR paradox paper [1] that Einstein co-authored remains one of my favourite "wrong" papers of all time.

This paper points out some of the most basic, paradigm shifting implications of entanglement and concludes, not that reality is truly this strange, but that the strangeness of these implications indicate the theory is incomplete. To be completely fair to Einstein, even if he had come up with Bell's inequalities at the time of writing this paper, they still would not have been possible to test with the technology of the day.

There is absolutely nothing to scoff at here. It may be wrong in it's conclusion, but the way in which it is wrong changed the course of physics. This is an example of how genius lies in asking the right questions even if you get the wrong answers. The EPR paradox remains a stunningly brilliant paper that should be closely ready by anyone in quantum physics.

Einstein was wrong, but in the most illuminating way possible!

[1]https://journals.aps.org/pr/pdf/10.1103/PhysRev.47.777

timberfox5• 4 years ago

I wouldn't say Einstein was wrong. It is a sad story that he never got to see the work of Nobel laureate Julian Schwinger on Quantum Field Theory, or the contributions of other Nobel laureates like Frank Wilczek. Switching from a particle-centric theory (like Quantum Mechanics) to a field-centric theory makes all the QM paradoxes disappear, and problems like locality, the double-slit experiment, etc., become trivial. What we have been calling particles are instead oscillators in fields. The Schrödinger equation is a wave function, but Quantum Mechanics has been using it to represent a probability distribution instead of an actual wave. Why is that? Because of the focus on particles. If everything has to be a particle, then of course we have to use a wave function as a probability distribution. But why force that view? We know how to describe fields since the days of Faraday and Maxwell, yet after Copenhagen all we want to do is to force wave-describing partial differential equations into a probabilistic model full of paradoxes.

solarengineer• 4 years ago

Goodness!! Thanks for articulating this so well!!

petmon• 4 years ago

The case for particles is quantization. We've never seen half a photon or half an electron. This dates back to the ultraviolet catastrophe. If it was all about waves that would be easy; we reluctantly acknowledge particles because Nature has forced us to.

bluepnume5• 4 years ago

I take it you're a MWI fan then? Isn't the answer for why we "force wave-describing partial differential equations into a probabilistic model" because in our reality, when we look at an electron we observe something that looks like a particle and not a wave?

TheOtherHobbes• 4 years ago

The designers of the LHC will be very surprised to learn their machine is just twisting fields together.

You can easily count individual photons, electrons, etc in an undergrad physics lab. How do you think that's possible with fields alone?

There's an interest in particles because there is no way to measure fields directly and the output of QFT is a set of particle-like probabilities.

This is not a trivial problem, QFT is not a trivial solution to it, and the paradoxes really haven't gone away.

OscarCunningham• 4 years ago

But quantum field theory doesn't replace probability distributions on particles with fields; it replaces them with probability distributions on fields.

quantum_state2• 4 years ago

Would like to follow up on your assertion:

“Switching from a particle-centric theory (like Quantum Mechanics) to a field-centric theory makes all the QM paradoxes disappear, and problems like locality, the double-slit experiment, etc., become trivial.“

I feel the same way. Would you know of any references that described the actual experiments seemingly revealing the paradoxes from quantum field theory perspective? Would appreciate it if you could share the references. Thanks!

bsder• 4 years ago

One of the big issues that both Einstein and Bohr had was that the experiments available to them at the time were only statistical--actually creating experiments with single quantum states or small quantum states was just not feasible.

For example, one of the arguments against Einstein's view was that Einstein's formulation implied that electrons in an excited atomic orbital would never decay. This, of course, is quite problematic as we know that electrons in atoms always decay.

Except that they don't!

When we put individual excited atoms in modern laser traps, we find that they don't drop from their excited state at the same rate. And the better the isolation, the slower that decay occurs. Whoops.

So, the problem is that these two greats were arguing with each other when a whole lot of the experimental evidence was still quite shaky and sometimes even wrong.

treve• 4 years ago

As a person who's been interested in physics but without any depth at all, this was a very interesting article and I'm kind of relieved that it's not settled.

bluepnume5• 4 years ago

Sadly it's not settled in large part because many physicists have stopped caring about more fundamental interpretations or explanations for QM. "The theory works, the math checks out, so we're done" -- and we're left without a really satisfactory explanation for why or how it works.

pmoriarty2• 4 years ago

Feynman famously admonished his students to "shut up and calculate" -- a pathetic attitude that's tantamount to surrender.

I much prefer Benjamin Disraeli's "All is mystery; but he is a slave who will not struggle to penetrate the dark veil."

m12k• 4 years ago

How certain are we at this point, that there are no hidden variables in quantum mechanics?

I'm asking because I read an article a while ago about some advances in higher-dimensional math that turned out to simplify certain quantum mechanical computations [1]. And it got my hopes up that we might eventually see quantum mechanics explained this way - e.g. as a projection/cross-section of higher dimensional phenomena into our 3D/4D reality. That the "weirdness" of QM could be explained by the effects happening in higher dimensional space. But from our perspective those would be hidden variables, so I'm curious whether we've been able to rule those out completely, or only partially?

[1] https://www.quantamagazine.org/physicists-discover-geometry-...

sterlind2• 4 years ago

iirc local hidden variables have been ruled out experimentally. global hidden variables have not, and form the basis of Pilot Wave Theory, but pilot waves have a lot of unresolved issues, and there's no full theory that explains what MWI and Copenhagen do.

alexfromapex2• 4 years ago

When you look at entanglement it seems like interaction in a higher dimension is one of the only plausible explanations

DebtDeflation• 4 years ago

I think, ultimately, there are only 3 possible explanations for the paradoxes of the quantum world. 1) superdeterminism (everything including our choices in quantum experiments today were fully determined at the instant of the Big Bang), 2) something "outside" our observable reality acting as a global hidden variable (whether something like the bulk in brane cosmology or whatever is running the simulation in simulation theory) or 3) emergent spacetime (if space and time are emergent phenomena then locality and causation are not fundamental).

ajuc2• 4 years ago

We are certain that there are no local hidden variables because of https://en.wikipedia.org/wiki/Hidden-variable_theory#Bell's_...

ynniv2• 4 years ago

Until it's "Bell's Law", I think we should consider quantum mechanics a statistical approximation. Every time QM is questioned people point to Bell's Theorem and challenge anyone to disprove it, when it seems to me that it is QM which is making extraordinary claims that require extraordinary evidence. Every theory of physics has at one point been "the ultimate", and they have all been replaced by better theories as our ability to investigate has expanded.

miltondts3• 4 years ago

I just want to correct some comments that say we are certain there are no local variables and that they have been ruled out experimentally.

This is false information and even Bell himself knew it:

"There is a way to escape the inference of superluminal speeds and spooky action at a distance. But it involves absolute determinism in the universe, the complete absence of free will."

https://en.wikipedia.org/wiki/Superdeterminism#Overview

doliveira• 4 years ago

I'd say superdeterminism is an even stronger version of global hidden variables

kryptiskt• 4 years ago

That's not local variables, that's a global conspiracy. And it's an unfalsifiable cop-out to the problem.

ko274• 4 years ago

Okay, I just want to correct you that superdeterminism is not a local hidden variable theory.

ncmncm5• 4 years ago

So, what is supposed to be wrong with "the complete absence of free will"?

It reads like some sort of religious objection. If the data leads you there, you go there.

Sabine, particularly, goes there. Apparently there are no actual problems with giving up the illusion of "free will", whatever the hell it was supposed to mean in the first place.

Distaste seems pretty rich coming from people promoting MWI.

akomtu2• 4 years ago

Chess is superdeterministic as all the moves are known in advance, but free will is still there. The "reality" might be such a superdeterministic playground that simply tells what the possible next moves are, while the players keep a pointer to one "chess" position and advance it one step at a time with their free will.

im3w1l• 4 years ago

So I was going to write a response to this but then I realized something.

1. The wavefunction is non-local, it contains non-local entanglements. Many-worlds even says it describes the whole world.

2. The wavefunction cannot be directly observed.

3. Many worlds interpretation doesn't have a notion of collapse - there is no randomness.

So if you think about it, MWI is a deterministic global hidden variable theory. I have no idea how I didn't see it until now.

alexfromapex2• 4 years ago

I have to go with Einstein on this debate, i.e. suspecting that there’s a deeper phenomena yet to be revealed. The failure to realize a Grand Unified Theory of Everything shows that there are still many unknowns leaving his theory as a possibility. Also, a simple thought experiment reveals that even with the Higgs field it’s nonsensical that there could be the existence of a fundamentally small particle because everything must be made of something smaller.

My takeaway from this article as a nonphysicist was that it’s satire.

pelorat• 4 years ago

I'm with Einstein on this one. The statistical math we use in quantum mechanics is not "real", it's an human invention to approximate something that we don't understand yet. Id est, a mathematical model that approximates, but does not describe the real truth about the physical universe.

3170702• 4 years ago

You hold that position without understanding Bell's inequality (like Einstein) or despite Bell's inequality?

swyx2• 4 years ago

do you mind explaining Bell's inequality? i looked up the wikipedia but it is very wordy and has a lot of equations; i need it stripped of Ponderousness as Scott Aaronson did in this piece

otikik• 4 years ago

Doesn’t that apply to all models used by physics, though? All of it is “with what we know right now”. New measurements and new experiments can always modify a constant or an equation.

pmoriarty2• 4 years ago

The statistical math we use in quantum mechanics is not "real", it's an human invention to approximate something that we don't understand yet.

What does it mean to understand something?

You could argue understanding is just as much a human invention as math is.

"Reality" (if there is such a thing) is independent of anything the human mind comes up with (whether that's understanding, math, or something else).... or is it?

ko274• 4 years ago

Math and equations don't have to reflect reality, but you are missing the point. The problem is with the very real experimental result of QM. Whichever theory or interpretation you come up to explain it, it won't make it any less weird.

unixhero2• 4 years ago

Well there is is Weinstein's Unified Field Theory. It proposes something at the side of Quantum Mechanics.

Presentation, https://youtu.be/Z7rd04KzLcg

https://theportal.wiki/wiki/Theory_of_Geometric_Unity

swyx2• 4 years ago

i somewhat wonder if he is taken less seriously because he doesnt have a university affiliation and chooses to present his stuff on podcast/youtube.

for the more educated - how "crackpot" is Weinstein? I have trouble assessing how full of himself he obviously is vs how much of a genius he also is.

unixhero2• 4 years ago

Weinstein is the director of Thiel capital and holds a PhD. I do not think he is a crackpot. He is butthurt over being victimized in academia for various reasons, and he is not alone in having such experienced. He is using his voice to call them out at the same time Publishing his work.

Regarding the theory. It is is impossible to me to analyze his work, because it is impenetrable. What is a two-tensor, gauge theory, I for one have absolutely no idea. I think this is an Achilles heel of his approach, he needs to convey meaning better. Or maybe that's just how a theory of everything is articulated.

ttctciyf• 4 years ago

For some reason, I'm reminded of the quotidian title of Dennet's Consciousness Explained.

tzs• 4 years ago

There have been several comments on particles vs waves, which is more real, possibilities of hidden variables, and similar.

People interested in those questions might like some of the more recent looks at QM that are based on information theory. Zeilinger has an approach based on the idea that various aspects of particles can only have one bit of information.

From this he's able to derive entanglement, the uncertainty principle, the Schrödinger equation, and more.

PBS Space Time did an episode on this just over a month ago [1].

[1] https://www.youtube.com/watch?v=v-aP1J-BdvE

lamontcg2• 4 years ago

Bohr really didn't offer anything to the debate other than some hand waving philosophical arguments about how you just can't ask anything about what is inside the box until you look.

Einstein, Podolsky and Rosen put the argument into mathematically solid and testable form. Einstein really 'wins' the argument in my mind either way it turns out because his name is attached to the actual experiment you can run to try to settle the question.

He also got the Nobel prize for the photoelectric effect and directly helped to invent quantum mechanics. The idea that there's this Einstein-vs-QM WWE event is sort of false. He'd probably be more or less happy with the way things turned out since quantum observation can't be used for superluminal communication. It turns out QM is nonlocal, but it still has rules.

If Einstein had lived to 143+ and was still around it might be interesting to ask where we'd be, since I don't think he would have accepted the just sort of shrug-and-accept-it-MWI approach to quantum observation. He'd probably be busy with something like twistor theory and trying to turn matter into tiny wormholes in space-time that can stretch and break and produce QM.

8bitsrule• 4 years ago

I'm still waiting to see what happens when someone dares to take a shot at describing the physical universe while eliminating 'time' from the equations.

Yeah, it can a useful ruler as a way to map changes; it's as real as a 'cubit', but not the territory. Energies may suffice. Things are constantly changing ... but only, and forever, Now. Without time, entanglement's no surprise.

InfiniteRand• 4 years ago

What bugs me somewhat with quantum mechanics is if we give up on localism, how can we rely on any of the science preceding quantum mechanics or even the science behind the experimental equipment, it is very possible I am missing something here

Einstein-Bohr debate settled once and for all

Related Stories