When Bohr got it wrong: the impact of a little-known paper on quantum theory

https://physicsworld.com/a/when-bohr-got-it-wrong-the-impact-of-a-little-known-paper-on-the-development-of-quantum-theory/

by sohkamyung • 1 year ago

65 26 1 year ago

physicsworld.com

gsf_emergency2• 1 year ago

BKS virtual field -> pilot wave?

https://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

naasking3• 1 year ago

“Its radically new approach paved the way for a greater understanding, that methods and concepts of classical physics could not be carried over in a future quantum mechanics.”

This is incorrect. The Hamiltonian in both statistical and quantum mechanics has the same basic structure. Quantization is the only real difference, but the other methods and concepts are structurally the same.

It was also a crucial factor in Heisenberg’s argument that the probabilistic character of his matrix mechanics (and also of Schrödinger’s 1926 version of quantum mechanics, called wave mechanics) couldn’t be explained away as a statistical expression of our ignorance about the details, as it is in classical statistical mechanics.

Too bad that's an incorrect inference. Bohmian mechanics proves that this inference is incorrect, and it's not the only possibility either.

bowsamic2• 1 year ago

Quantisation is a pretty big difference: it turns the observables into completely different mathematical objects. Also the Hamiltonian itself only has the same form as in classical physics if at most quadratic in the canonical variables

whatshisface2• 1 year ago

The parent commenter was talking about Von Neumann mechanics.

fao_• 1 year ago

I'm sorry but I think I'm going to believe the man who wrote the article, who is an editor of Nature and has a Physics PhD[1], over someone who has made it their life's work to argue against established scientists on a website for Venture Capitalists :)

[1] https://en.wikipedia.org/wiki/Philip_Ball

whatshisface2• 1 year ago

Would you believe two? :-) Bohmian mechanics describes a classical pseudo random number generator that deterministically decides the outcome of quantum measurements, using instant communication between measurements so that conditional probability works. The modern rejection of classical uncertainty as an interpretation of quantum uncertainty stems from Bell's theorem, which shows that any model that achieves a similar philosophical goal as Bohmian mechanics has a similarly dissatisfactory reliance on instant communication. People of Heisenberg's generation had the right intuitions and were guessing in the right directions but they did not know Bell's theorem, or even that it was a worthwhile question.

naasking3• 1 year ago

If you look at polls of physicists over the past few decades, many believed that Von Neumann's proof ruled out all hidden variable theories. This was wrong. Many others also believed that Bell's theorem ruled out hidden variable theories. This was also wrong, and Bell himself was actually a fan of Bohmian mechanics, which is a non-local hidden variable theory, and one of his motivations for deriving his famous theorem.

All of this is to say that being a physicist doesn't make you an expert in quantum foundations. Neither am I, but I've read a diversity of literature from experts that work on quantum foundations, so I am aware of the range of misconceptions on this.

leephillips2• 1 year ago

This is an interesting article due to the historical connections it makes. I mention the paper in question on p. 120 of my book about Noether’s Theorem (https://lee-phillips.org/noether) and quote Heisenberg on why violation of energy conservation, and therefore the paper, was unacceptable (something that the article doesn’t really discuss—after all, other conservation laws were abandoned or modified as needed): it’s because Noether’s Theorem shows that energy conservation is equivalent to invariance with regard to time translation, something that no one would be willing to give up. This means that energy must be conserved in every interaction, not just statistically.

sohkamyung• 1 year ago

Your book is on my to-read list. :-)

leephillips2• 1 year ago

Glad to hear it! I hope you enjoy it.

ForOldHack• 1 year ago

Michelson–Morley got it wrong too, but getting things wrong, when you know its wrong, its an advancement.

oneshtein2• 1 year ago

LIGO is better version of Michelson–Morley experiment.

aeve890• 1 year ago

No. Both use Michelson interferometry techonology and that's all, but they differ significantly in purpose and outcome. They're literally different experiments, not one "a better version" of the other.

goryramsy• 1 year ago

I’d never heard of that… do you have an article about it so I can read up?

ioblomov• 1 year ago

The experiment disproved the existence of an ether by measuring that the speed of light was constant regardless of direction…

https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_exper...

(And special relativity soon showed that if the speed of light is constant, then time itself must be variable.)

ithkuil• 1 year ago

I believe GP refers to the fact that they set out to measure the speed of the earth relative to the aether only to discover there was no such thing.

gsf_emergency2• 1 year ago

Sorry to come off as a crackpot, but pilot-wave theory did try to fix the problems of BKS by forcing the conservation of energy-momentum in their updated version of the "virtual field".

Of course, Bohm also tried to do a sleight of hand with causality

When Bohr got it wrong: the impact of a little-known paper on quantum theory

Related Stories