15 ms·

On the Double-Slit Experiment and Quantum Interference in the Wolfram Model (2020)

77 points by floobertoober 3y ago

noneoftheabove 3y ago
[flagged]
- noneoftheabove 3y ago
  [flagged]
  - yetihehe 3y ago
    From comment guidelines: > Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. > Please don't fulminate. Please don't sneer, including at the rest of the community.
Ste_Tokyo 3y ago
[flagged]
- noneoftheabove 3y ago
  No need for crank. It’s wolfram. Hiding behind some accolades of past, lawsuits and other tangibly criminal offenses. The guy is smart enough To gear projects to ends that avoid crank threshold in the dictionary definition.
- thom 3y ago
  I’m sure it can fit basically any phenomenon, including an elephant wiggling its trunk. I too would like to see some actual predictions coming out of the model, but either way, I don’t begrudge him the effort. I’d like to believe what underlies our reality is more elegant than the high level mishmash we currently understand.
- evanb 3y ago
  That's not the kind of model it is. The standard model is one example of a quantum field theory. You should think of Wolfram's idea as a different formalism (ie. not QFT), not a different example. It so happens that Wolfram's multiway model (allegedly, I can't evaluate it fairly for myself) also contains GR as a low-energy limit. It's like inventing a new operating system (we currently have 3ish, Newtonian, Quantum, and GR) instead of writing a new program (baseball, orbital motion, chemistry, gravitational waves, etc.) Perhaps new programs can be written on this new OS that couldn't be written before. If known programs cannot run on this new OS then it is defective.
  - Ste_Tokyo 3y ago
    Of course it contains GR as a low-energy limit. Where it can be physically checked, it is equivalent to the existing successful theory; where it makes new predictions, it can't be checked and so is almost certainly wrong. To make progress in physics you need to apply yourself to a real open problem (like "Dark Matter") or get new data (from quantum computers or primordial gravitational waves, maybe). The only good thing that can be said about Wolfram is that he is not paid with my taxes, because plenty of cranks in physics are.
  - luc4sdreyer 3y ago
    >If known programs cannot run on this new OS then it is defective. I understand the problem is that, like String Theory, this framework has a practically unlimited supply of variables that can simply be tuned to fit existing experiments, while not offering any way to be tested.
    - evanb 3y ago
      Indeed! But it is beneficial to have additional formalisms; it gives you hints about what kind of modifications to 'normal' physics might be possible.
- emblaegh 3y ago
  I can imagine you snubbing Hamilton by going all "can the least action principle explain a single phenomenon not already explained by the forces + newton's laws? Thought not. Crank". I have no idea what worfram's model is about, and I agree that the language he uses to publicise it is kinda twatty. However your insane criterion for what constitutes a theory/formalism worth exploring is clearly guided by your bias against the man.
  - Ste_Tokyo 3y ago
    Does the "Wolfram Model" allow easier analysis of certain physical situations like the Hamiltonian does? Thought not. So what's your point?
- goodmachine 3y ago
  As Gorard has long been at pains to point out (and Wolfram, being preternaturally immodest, has not) the model is a formalism, not a theory. That said, the point of redescribing things we know very well - like QM and GR - in new ways is ultimately to make testable predictions. So: https://www.youtube.com/watch?v=XLtxXkugd5w https://www.youtube.com/watch?v=XLtxXkugd5w
- meindnoch 3y ago
  It cannot even explain the standard model and/or general relativity either. It's a (hyper)graph rewriting system, that they say can reproduce existing physics with some set of rules and some initial conditions. Which is tautologically true. Any Turing complete system (e.g. Conway's Game of Life) can reproduce the physical world with large enough memory and enough time.
noname120 3y ago
[2020]
luc4sdreyer 3y ago
This is from four years ago, and there are some comments on the article by Matt Kelly that show that the "interference pattern" is just an artefact. The author did not respond despite several requests to do so.
jahnu 3y ago
Mindscape episode with Stephen Wolfram from 2021 which might also be of interest. I enjoyed it even if most of it was way over my head. It is probably overly-ambitious and probably a dead end but it's an worthy attempt (if you have the money) and he's definitely not a crank. Eccentric maybe though. https://www.preposterousuniverse.com/podcast/2021/07/12/155-stephen-wolfram-on-computation-hypergraphs-and-fundamental-physics/ https://www.preposterousuniverse.com/podcast/2021/07/12/155-...
weinzierl 3y ago
I often wonder how much the fact that quantum mechanics' original formulation was in terms of a wave function and differential equations has to do with the ubiquity and importance of these topics at that particular era. For example, Werner Heisenberg's doctoral thesis[1] arose from a contract of his doctor father Arnold Sommerfeld from a company that dealt with the channelling of the Isar river through the city of Munich. Very practical problems involving differential equations - kind of the bread and butter of physicists and engineers at the time. What if quantum mechanics was found today in a world where the bread and butter has shifted to computer science, linear algebra and discrete math? Would we still end up with waves and differential equations, or would another formulation arise more naturally? EDIT: I think a beautiful (but imperfect) example to illustrate this dichotomy in the ways of thinking is how the Bell inequality can be approached with photons and polarization or as a game. Thinking about Alice and Bob or polarized light, which would you prefer? [1] https://ntrs.nasa.gov/citations/19930093939 https://ntrs.nasa.gov/citations/19930093939
- techwiz137 3y ago
  I think that without their contributions back then, we wouldn't have the computers of today.
- orra 3y ago
  It's an interesting question but matrix mechanics is already a thing. https://en.wikipedia.org/wiki/Matrix_mechanics https://en.wikipedia.org/wiki/Matrix_mechanics For me it's a reminder that physics describes how quantum systems evolve, but it doesn't (in a sense) tell us what those systems are. Are particles waves? Matrices? Excitations of a field? Each of these descriptions works, so I can't exclusively say any one of them is what particles really are. Bring a macroscopic being is philosophically frustrating.
- eigenket 3y ago
  It was formulated at least twice in different versions. First by Heisenberg with his matrix mechanics and shortly afterwards by Schrödinger in terms of wave-functions. There was considerable disagreement between the factions of physicists who favoured the different versions which essentially ended when after some considerable theoretical effort (mostly by Dirac) it was shown that the two pictures are exactly equivalent. Physicists still use whichever formulation is most suitable for whatever problem they're trying to solve, for example if you're analysing the something where you care about a bunch of bound states like the simple harmonic oscillator or the hydrogen atom then the matrix picture tends to be easier to work with. You are right that wave mechanics was more popular than matrix mechanics because physicists were already very familiar with wave methods.
deleted 3y ago
[deleted]
eigenket 3y ago
This comment by Matt Kelly seems to be the most pertinent > Regarding the similarity to a double slit interference pattern, what I found in my investigation (see my previous comment) is it was solely the result of the sorting algorithm used for the X coordinates of each possible outcome/weight. Ordering by the average X location results in a binomial distribution, but there are still ties to deal with. Applying secondary sorting to those based on the position of the left or rightmost X creates secondary binomial distributions within the main binomial distribution, similar to what Jonathan showed, except without all the spikiness because his example wasn’t consistently sorted in this manner. > You can see the sorting I’m talking about by looking at the sorting of Xs in the output of weights in Jonathan’s double-slit examples. The bottom half is sorted as I stated, but the top half is somewhat out of order, corresponding to the spikes in the tallest curve in the center of the graphs. > Maxime C, I had the same question as you – Why choose this sorting method for encoding the photon positions? My conclusion is that it doesn’t work however. Each additional step run with a large string produces an additional secondary binomial distribution. To get a smooth curve, we’d need to run billions of steps on a large string, but then we we’d also see billions of peaks, which no longer compares well with the expected diffraction pattern.
danbruc 3y ago
I just skimmed the article for sanity checking and it looks more like crackpottery than science to me. Looking at the numbers on the graphs for single-slit diffraction, they are just binomial coefficient, at least mostly, not sure why there are pieces missing in the last rows. That is also what you expect when you repeatedly make binary decisions to go left or right. The article does not mention the binomial distributions once, it only appears in a comment. And then they claim that it converge to the actual single-slit diffraction distribution, something with a Chebyshev polynomial and the sinc function, according to the article. Seemingly without justification besides looking at graphs and noting that they are both bell shaped. As said, not sure what is going on in the last rows of the graphs, but I would almost bet that the two functions are not the same, even in the limit as it becomes a Poisson distribution plus whatever the last rows do. Why do they not just proof that the two are the same? The entire article seems to be about getting numbers out of their multiway system and then concluding that - if you squint hard enough - they look somewhat like diffraction patterns.
- vingt_regards 3y ago
  > I would almost bet that the two functions are not the same, even in the limit as it becomes a Poisson distribution plus whatever the last rows do. A Gaussian distribution, I think. But they're certaintly not the same function, and it should be immediately obvious to a math grad with experience in physics. The sinc function, for one, has secondary maxima (its plot in the article is very convenienty cropped to allow pretending those don't exist). Just put a hair in the path of a laser beam and you will see the local maxima in light intensity! Their "single-slit" string procedure, on the other hand, can only generate a single central peak. This really makes no sense at all.
- andrewgleave 3y ago
  And by the third slit simulation they seem to have refuted their own hypothesis.
- deleted 3y ago
  [deleted]
meindnoch 3y ago
[flagged]
- deleted 3y ago
  [deleted]
deleted 3y ago
[deleted]
jereees 3y ago
On yesterday’s live stream[0] on Stephen Wolfram’s Twitch the team went through several improvement proposals to functions in WolframAlpha, including QuantumCircuitOperator which is a variant of a String Diagram. Before this I didn’t know Stephen hosted “Live CEOing” sessions and now I wish this was the norm! 0: https://www.twitch.tv/videos/2083073452 https://www.twitch.tv/videos/2083073452 (timestamp around 50:00)

77 points by floobertoober 3y ago

noneoftheabove 3y ago

[flagged]

noneoftheabove 3y ago
[flagged]
- yetihehe 3y ago
  From comment guidelines: > Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. > Please don't fulminate. Please don't sneer, including at the rest of the community.

Ste_Tokyo 3y ago

[flagged]

noneoftheabove 3y ago
No need for crank. It’s wolfram. Hiding behind some accolades of past, lawsuits and other tangibly criminal offenses. The guy is smart enough To gear projects to ends that avoid crank threshold in the dictionary definition.
thom 3y ago
I’m sure it can fit basically any phenomenon, including an elephant wiggling its trunk. I too would like to see some actual predictions coming out of the model, but either way, I don’t begrudge him the effort. I’d like to believe what underlies our reality is more elegant than the high level mishmash we currently understand.
evanb 3y ago
That's not the kind of model it is. The standard model is one example of a quantum field theory. You should think of Wolfram's idea as a different formalism (ie. not QFT), not a different example. It so happens that Wolfram's multiway model (allegedly, I can't evaluate it fairly for myself) also contains GR as a low-energy limit. It's like inventing a new operating system (we currently have 3ish, Newtonian, Quantum, and GR) instead of writing a new program (baseball, orbital motion, chemistry, gravitational waves, etc.) Perhaps new programs can be written on this new OS that couldn't be written before. If known programs cannot run on this new OS then it is defective.
- Ste_Tokyo 3y ago
  Of course it contains GR as a low-energy limit. Where it can be physically checked, it is equivalent to the existing successful theory; where it makes new predictions, it can't be checked and so is almost certainly wrong. To make progress in physics you need to apply yourself to a real open problem (like "Dark Matter") or get new data (from quantum computers or primordial gravitational waves, maybe). The only good thing that can be said about Wolfram is that he is not paid with my taxes, because plenty of cranks in physics are.
- luc4sdreyer 3y ago
  >If known programs cannot run on this new OS then it is defective. I understand the problem is that, like String Theory, this framework has a practically unlimited supply of variables that can simply be tuned to fit existing experiments, while not offering any way to be tested.
  - evanb 3y ago
    Indeed! But it is beneficial to have additional formalisms; it gives you hints about what kind of modifications to 'normal' physics might be possible.
emblaegh 3y ago
I can imagine you snubbing Hamilton by going all "can the least action principle explain a single phenomenon not already explained by the forces + newton's laws? Thought not. Crank". I have no idea what worfram's model is about, and I agree that the language he uses to publicise it is kinda twatty. However your insane criterion for what constitutes a theory/formalism worth exploring is clearly guided by your bias against the man.
- Ste_Tokyo 3y ago
  Does the "Wolfram Model" allow easier analysis of certain physical situations like the Hamiltonian does? Thought not. So what's your point?
goodmachine 3y ago
As Gorard has long been at pains to point out (and Wolfram, being preternaturally immodest, has not) the model is a formalism, not a theory. That said, the point of redescribing things we know very well - like QM and GR - in new ways is ultimately to make testable predictions. So: https://www.youtube.com/watch?v=XLtxXkugd5w https://www.youtube.com/watch?v=XLtxXkugd5w
meindnoch 3y ago
It cannot even explain the standard model and/or general relativity either. It's a (hyper)graph rewriting system, that they say can reproduce existing physics with some set of rules and some initial conditions. Which is tautologically true. Any Turing complete system (e.g. Conway's Game of Life) can reproduce the physical world with large enough memory and enough time.

noname120 3y ago

[2020]

luc4sdreyer 3y ago

This is from four years ago, and there are some comments on the article by Matt Kelly that show that the "interference pattern" is just an artefact. The author did not respond despite several requests to do so.

jahnu 3y ago

Mindscape episode with Stephen Wolfram from 2021 which might also be of interest. I enjoyed it even if most of it was way over my head. It is probably overly-ambitious and probably a dead end but it's an worthy attempt (if you have the money) and he's definitely not a crank. Eccentric maybe though. https://www.preposterousuniverse.com/podcast/2021/07/12/155-stephen-wolfram-on-computation-hypergraphs-and-fundamental-physics/ https://www.preposterousuniverse.com/podcast/2021/07/12/155-...

weinzierl 3y ago

I often wonder how much the fact that quantum mechanics' original formulation was in terms of a wave function and differential equations has to do with the ubiquity and importance of these topics at that particular era. For example, Werner Heisenberg's doctoral thesis[1] arose from a contract of his doctor father Arnold Sommerfeld from a company that dealt with the channelling of the Isar river through the city of Munich. Very practical problems involving differential equations - kind of the bread and butter of physicists and engineers at the time. What if quantum mechanics was found today in a world where the bread and butter has shifted to computer science, linear algebra and discrete math? Would we still end up with waves and differential equations, or would another formulation arise more naturally? EDIT: I think a beautiful (but imperfect) example to illustrate this dichotomy in the ways of thinking is how the Bell inequality can be approached with photons and polarization or as a game. Thinking about Alice and Bob or polarized light, which would you prefer? [1] https://ntrs.nasa.gov/citations/19930093939 https://ntrs.nasa.gov/citations/19930093939

techwiz137 3y ago
I think that without their contributions back then, we wouldn't have the computers of today.
orra 3y ago
It's an interesting question but matrix mechanics is already a thing. https://en.wikipedia.org/wiki/Matrix_mechanics https://en.wikipedia.org/wiki/Matrix_mechanics For me it's a reminder that physics describes how quantum systems evolve, but it doesn't (in a sense) tell us what those systems are. Are particles waves? Matrices? Excitations of a field? Each of these descriptions works, so I can't exclusively say any one of them is what particles really are. Bring a macroscopic being is philosophically frustrating.
eigenket 3y ago
It was formulated at least twice in different versions. First by Heisenberg with his matrix mechanics and shortly afterwards by Schrödinger in terms of wave-functions. There was considerable disagreement between the factions of physicists who favoured the different versions which essentially ended when after some considerable theoretical effort (mostly by Dirac) it was shown that the two pictures are exactly equivalent. Physicists still use whichever formulation is most suitable for whatever problem they're trying to solve, for example if you're analysing the something where you care about a bunch of bound states like the simple harmonic oscillator or the hydrogen atom then the matrix picture tends to be easier to work with. You are right that wave mechanics was more popular than matrix mechanics because physicists were already very familiar with wave methods.

deleted 3y ago

[deleted]

eigenket 3y ago

This comment by Matt Kelly seems to be the most pertinent > Regarding the similarity to a double slit interference pattern, what I found in my investigation (see my previous comment) is it was solely the result of the sorting algorithm used for the X coordinates of each possible outcome/weight. Ordering by the average X location results in a binomial distribution, but there are still ties to deal with. Applying secondary sorting to those based on the position of the left or rightmost X creates secondary binomial distributions within the main binomial distribution, similar to what Jonathan showed, except without all the spikiness because his example wasn’t consistently sorted in this manner. > You can see the sorting I’m talking about by looking at the sorting of Xs in the output of weights in Jonathan’s double-slit examples. The bottom half is sorted as I stated, but the top half is somewhat out of order, corresponding to the spikes in the tallest curve in the center of the graphs. > Maxime C, I had the same question as you – Why choose this sorting method for encoding the photon positions? My conclusion is that it doesn’t work however. Each additional step run with a large string produces an additional secondary binomial distribution. To get a smooth curve, we’d need to run billions of steps on a large string, but then we we’d also see billions of peaks, which no longer compares well with the expected diffraction pattern.

danbruc 3y ago

I just skimmed the article for sanity checking and it looks more like crackpottery than science to me. Looking at the numbers on the graphs for single-slit diffraction, they are just binomial coefficient, at least mostly, not sure why there are pieces missing in the last rows. That is also what you expect when you repeatedly make binary decisions to go left or right. The article does not mention the binomial distributions once, it only appears in a comment. And then they claim that it converge to the actual single-slit diffraction distribution, something with a Chebyshev polynomial and the sinc function, according to the article. Seemingly without justification besides looking at graphs and noting that they are both bell shaped. As said, not sure what is going on in the last rows of the graphs, but I would almost bet that the two functions are not the same, even in the limit as it becomes a Poisson distribution plus whatever the last rows do. Why do they not just proof that the two are the same? The entire article seems to be about getting numbers out of their multiway system and then concluding that - if you squint hard enough - they look somewhat like diffraction patterns.

vingt_regards 3y ago
> I would almost bet that the two functions are not the same, even in the limit as it becomes a Poisson distribution plus whatever the last rows do. A Gaussian distribution, I think. But they're certaintly not the same function, and it should be immediately obvious to a math grad with experience in physics. The sinc function, for one, has secondary maxima (its plot in the article is very convenienty cropped to allow pretending those don't exist). Just put a hair in the path of a laser beam and you will see the local maxima in light intensity! Their "single-slit" string procedure, on the other hand, can only generate a single central peak. This really makes no sense at all.
andrewgleave 3y ago
And by the third slit simulation they seem to have refuted their own hypothesis.
deleted 3y ago
[deleted]

meindnoch 3y ago

[flagged]

deleted 3y ago
[deleted]

deleted 3y ago

[deleted]

jereees 3y ago

On yesterday’s live stream[0] on Stephen Wolfram’s Twitch the team went through several improvement proposals to functions in WolframAlpha, including QuantumCircuitOperator which is a variant of a String Diagram. Before this I didn’t know Stephen hosted “Live CEOing” sessions and now I wish this was the norm! 0: https://www.twitch.tv/videos/2083073452 https://www.twitch.tv/videos/2083073452 (timestamp around 50:00)