6 ms·

I feel like the algorithm is maybe poorly named. At first I thought this was a tool to help with computational quantum physics.

stagas 5y ago
Very naive question but is it even possible to do quantum experiments with code on a regular computer? Anyone knows if it's been tried?
- rndphs 5y ago
  You can simulate quantum dynamics but the number of bits required is exponential with respect to the number of qubits simulated. So basically you can simulate really simple quantum systems but it becomes pretty much intractable when the system you are simulating has many parts.
- nabla9 5y ago
  Yes. It's just an equation. The complexity of quantum system that can be simulate is limited. https://marl0ny.github.io/QM-Simulator-2D/index.html https://marl0ny.github.io/QM-Simulator-2D/index.html From the above link you can look single slit, double slit, triple slit, step, spike, or load an arbitrary image as a potential and do experiments in 2d box. >This WebGL program simulates the quantum mechanics of a single particle confined in a 2D box, where inside this box the user can create new potential barriers and scatter Gaussian wavepackets off them. The full instructions are found here. https://github.com/marl0ny/QM-Simulator-2D https://github.com/marl0ny/QM-Simulator-2D btw. Wave function collapse in quantum physics is completely speculative phenomenon. There is only apparent wave function collapse.
  - tsimionescu 5y ago
    > btw. Wave function collapse in quantum physics is completely speculative phenomenon. There is only apparent wave function collapse. To be more precise, the Born rule non-linear adjustment of the wave function to a single real value after a measurement is strictly necessary for QM to match experiments. Whether this should be interpreted as a physical phenomenon of wave function collapse, or as entanglement with the environment (MWI), or as an update of probabilities for hidden variables (Pilot wave) or some other phenomenon is speculative, but the wave function must be "collapsed" to a single real value after a measurement to correctly predict experimental results.
    - nabla9 5y ago
      Adjustment is just cutting interference terms from equation. Mathematically apparent wave function collapse is caused by quantum decoherence. Wave-function collapse as a priori process is just speculation. Finding that it actually happens would be new physics.
      - wizzwizz4 5y ago
        In which case, where does the Born rule come from?
        nabla9 5y ago
        https://en.wikipedia.org/wiki/Gleason%27s_theorem https://en.wikipedia.org/wiki/Gleason%27s_theorem
        wizzwizz4 5y ago
        Huh. I can't believe I missed this. Thanks.
        nabla9 5y ago
        In quantum computing the consequence of the theorem (as I understand it) is that once you have asked every yes/no question there is to ask about the state, the state has collapsed.
        wizzwizz4 5y ago
        I didn't think you needed the theorem for that; quantum entanglement behaves very similarly to information theory (specifically, information provenance).
        tsimionescu 5y ago
        As far as I can tell, that is just explaining the numeric value of the Born rule, not the wave function collapse/update. I have not found any claims that Gleason's theorem (which I was unaware of, so thank you for pointing it out!) solves the measurement problem.
  - Extigy 5y ago
    If you like that simulation you might also like my own webGL Gross-Pitaevskii Equation (GPE) solver. It uses RK4 to simulate a 2D box of ultracold atoms undergoing Bose-Einstein Condensation. The GPE models a condensate as a single-particle quantum wavefunction with a non-linear form of the Schrödinger Equation, so you get some interesting behaviour from the non-linearity while the simulation remains computationally feasible. You can interact with the potential term by clicking and dragging inside the 2D box. https://georgestagg.github.io/webgl_gpe/ https://georgestagg.github.io/webgl_gpe/
- jeffwass 5y ago
  Sure. We’ve been doing quantum theory with pencil and paper for over a century!
deleted 5y ago
[deleted]
t8y 5y ago
Wave Function Collapse is actually the same (or essentially identical) as Model Synthesis[1]. IMO that is a better name. [1]https://paulmerrell.org/model-synthesis/ https://paulmerrell.org/model-synthesis/
- mlochbaum 5y ago
  Taking a look at the comparison paper [0] provided on that site, there does seem to be a significant difference. The images generated with MS are more prone to long horizontal lines while WFC produces larger blocks of texture. This is hard to spot with more homogeneous textures like pipes, but it's more apparent with something like the grey cat faces, where WFC generates a variety of shapes and MS mostly makes very long ones. Going back up to section 2 I found the explanation: "Model synthesis sweeps through the grid in scanline order. WFC chooses the lowest entropy cell." The results from WFC look more natural and varied to me so I'd call this a significant advance. But it does seem appropriate to say they're variations of the same algorithm. As for the name, I don't like either: Wave Function Collapse is based on a silly pop-science interpretation of quantum mechanics, and Model Synthesis is extremely generic and forgettable. And it's not even a synthesis, more of a filtering process. I guess I'd stick with Wave Function Collapse. [0] https://paulmerrell.org/wp-content/uploads/2021/07/comparison.pdf https://paulmerrell.org/wp-content/uploads/2021/07/compariso...
karimabuseer 5y ago
I thought the same - though it actually gets its name from wave function collapse in quantum physics, as each pixel has multiple potential positions it can collapse to, leading to the procedurally generated map
- judofyr 5y ago
  As someone who has actually studied physics (including quantum mechanics) I find this analogy extremely poor. Keeping multiple potential candidates which you gradually reduce into a single solution is a very common approach for solving a variety of problems (e.g. sudoku solver). This is not at all what makes the wave function interesting or useful in quantum mechanics. And the whole concept that you iteratively collapse each "wave element" isn't a thing which is present in quantum mechanics at all. Oh well, I guess people like the fancy name.
  - pixelpoet 5y ago
    > Oh well, I guess people like the fancy name. The way "quantum leap" is used by laypeople springs to mind too; literally the opposite of what they mean (not only tiny but random).
    - gmadsen 5y ago
      is it though? I've heard the argument, but to me it still makes sense as it is used colloquially. It is a discrete jump forward, thus if you are not talking about electrons and just the latin definition can be an arbitrary sized quanta if defined to an an appropriate set. a quantum leap between scientific epochs is quite large for example also just reread your comment. I don't agree with the definition "small and random", it is smallest unit of measurement an arbitrary system magnitude can change
      - skulk 5y ago
        Here's my interpretation: a classical leap is when you are somewhere, you expend a bit of energy you have, and you end up somewhere else as a result. Basically, you do something and something happens. A quantum leap, on the other hand, happens when you are somewhere just sitting, and boom, now you're somewhere else. It just happened randomly, without any energy input from you. So to bring this back to the idiom, an example of a quantum leap would be this: "I had a dream yesterday that gave me the insight I needed to finish my proof of XYZ theorem!"
JoeyBananas 5y ago
It's also not clear what this algorithm has to do with quantum physics. Maybe that's how it was discovered or it has applications to physics, but the algorithm itself doesn't require any advanced math or have anything to do with the wave function. It can be described using elementary combinatorics.
ArtWomb 5y ago
This gets brought up every time its mentioned. And I think its interesting. It's only tangentially related to actual physics. But parallelizing the WFC for large inputs might be exactly the kind of problem QC assists.
munificent 5y ago
It's reasonable to be surprised when a computer science term uses a metaphor, but I don't think it's fair to call it a poor name unless you also object to almost every other name in programming. Strings have nothing to do with textiles. And, very confusingly, they aren't even related to fibers or threads. Zippers aren't related to textiles either. Trees and bloom filters are not related to botany. Heaps and garbage collection are not about municipal waste management. Graph coloring, despite the term, has nothing to do with either pictures or pigments. Red-black trees aren't colored or botanical. Bubble sort does not involve fluid dynamics. Neither does bucket or cocktail shaker sort for that matter. Circular buffers are not round. You can't eat a spaghetti stack or poke your finger on a cactus stack.

stagas 5y ago

Very naive question but is it even possible to do quantum experiments with code on a regular computer? Anyone knows if it's been tried?

rndphs 5y ago
You can simulate quantum dynamics but the number of bits required is exponential with respect to the number of qubits simulated. So basically you can simulate really simple quantum systems but it becomes pretty much intractable when the system you are simulating has many parts.
nabla9 5y ago
Yes. It's just an equation. The complexity of quantum system that can be simulate is limited. https://marl0ny.github.io/QM-Simulator-2D/index.html https://marl0ny.github.io/QM-Simulator-2D/index.html From the above link you can look single slit, double slit, triple slit, step, spike, or load an arbitrary image as a potential and do experiments in 2d box. >This WebGL program simulates the quantum mechanics of a single particle confined in a 2D box, where inside this box the user can create new potential barriers and scatter Gaussian wavepackets off them. The full instructions are found here. https://github.com/marl0ny/QM-Simulator-2D https://github.com/marl0ny/QM-Simulator-2D btw. Wave function collapse in quantum physics is completely speculative phenomenon. There is only apparent wave function collapse.
- tsimionescu 5y ago
  > btw. Wave function collapse in quantum physics is completely speculative phenomenon. There is only apparent wave function collapse. To be more precise, the Born rule non-linear adjustment of the wave function to a single real value after a measurement is strictly necessary for QM to match experiments. Whether this should be interpreted as a physical phenomenon of wave function collapse, or as entanglement with the environment (MWI), or as an update of probabilities for hidden variables (Pilot wave) or some other phenomenon is speculative, but the wave function must be "collapsed" to a single real value after a measurement to correctly predict experimental results.
  - nabla9 5y ago
    Adjustment is just cutting interference terms from equation. Mathematically apparent wave function collapse is caused by quantum decoherence. Wave-function collapse as a priori process is just speculation. Finding that it actually happens would be new physics.
    - wizzwizz4 5y ago
      In which case, where does the Born rule come from?
      - nabla9 5y ago
        https://en.wikipedia.org/wiki/Gleason%27s_theorem https://en.wikipedia.org/wiki/Gleason%27s_theorem
        wizzwizz4 5y ago
        Huh. I can't believe I missed this. Thanks.
        nabla9 5y ago
        In quantum computing the consequence of the theorem (as I understand it) is that once you have asked every yes/no question there is to ask about the state, the state has collapsed.
        wizzwizz4 5y ago
        I didn't think you needed the theorem for that; quantum entanglement behaves very similarly to information theory (specifically, information provenance).
        tsimionescu 5y ago
        As far as I can tell, that is just explaining the numeric value of the Born rule, not the wave function collapse/update. I have not found any claims that Gleason's theorem (which I was unaware of, so thank you for pointing it out!) solves the measurement problem.
- Extigy 5y ago
  If you like that simulation you might also like my own webGL Gross-Pitaevskii Equation (GPE) solver. It uses RK4 to simulate a 2D box of ultracold atoms undergoing Bose-Einstein Condensation. The GPE models a condensate as a single-particle quantum wavefunction with a non-linear form of the Schrödinger Equation, so you get some interesting behaviour from the non-linearity while the simulation remains computationally feasible. You can interact with the potential term by clicking and dragging inside the 2D box. https://georgestagg.github.io/webgl_gpe/ https://georgestagg.github.io/webgl_gpe/
jeffwass 5y ago
Sure. We’ve been doing quantum theory with pencil and paper for over a century!

deleted 5y ago

[deleted]

t8y 5y ago

Wave Function Collapse is actually the same (or essentially identical) as Model Synthesis[1]. IMO that is a better name. [1]https://paulmerrell.org/model-synthesis/ https://paulmerrell.org/model-synthesis/

mlochbaum 5y ago
Taking a look at the comparison paper [0] provided on that site, there does seem to be a significant difference. The images generated with MS are more prone to long horizontal lines while WFC produces larger blocks of texture. This is hard to spot with more homogeneous textures like pipes, but it's more apparent with something like the grey cat faces, where WFC generates a variety of shapes and MS mostly makes very long ones. Going back up to section 2 I found the explanation: "Model synthesis sweeps through the grid in scanline order. WFC chooses the lowest entropy cell." The results from WFC look more natural and varied to me so I'd call this a significant advance. But it does seem appropriate to say they're variations of the same algorithm. As for the name, I don't like either: Wave Function Collapse is based on a silly pop-science interpretation of quantum mechanics, and Model Synthesis is extremely generic and forgettable. And it's not even a synthesis, more of a filtering process. I guess I'd stick with Wave Function Collapse. [0] https://paulmerrell.org/wp-content/uploads/2021/07/comparison.pdf https://paulmerrell.org/wp-content/uploads/2021/07/compariso...

karimabuseer 5y ago

I thought the same - though it actually gets its name from wave function collapse in quantum physics, as each pixel has multiple potential positions it can collapse to, leading to the procedurally generated map

judofyr 5y ago
As someone who has actually studied physics (including quantum mechanics) I find this analogy extremely poor. Keeping multiple potential candidates which you gradually reduce into a single solution is a very common approach for solving a variety of problems (e.g. sudoku solver). This is not at all what makes the wave function interesting or useful in quantum mechanics. And the whole concept that you iteratively collapse each "wave element" isn't a thing which is present in quantum mechanics at all. Oh well, I guess people like the fancy name.
- pixelpoet 5y ago
  > Oh well, I guess people like the fancy name. The way "quantum leap" is used by laypeople springs to mind too; literally the opposite of what they mean (not only tiny but random).
  - gmadsen 5y ago
    is it though? I've heard the argument, but to me it still makes sense as it is used colloquially. It is a discrete jump forward, thus if you are not talking about electrons and just the latin definition can be an arbitrary sized quanta if defined to an an appropriate set. a quantum leap between scientific epochs is quite large for example also just reread your comment. I don't agree with the definition "small and random", it is smallest unit of measurement an arbitrary system magnitude can change
    - skulk 5y ago
      Here's my interpretation: a classical leap is when you are somewhere, you expend a bit of energy you have, and you end up somewhere else as a result. Basically, you do something and something happens. A quantum leap, on the other hand, happens when you are somewhere just sitting, and boom, now you're somewhere else. It just happened randomly, without any energy input from you. So to bring this back to the idiom, an example of a quantum leap would be this: "I had a dream yesterday that gave me the insight I needed to finish my proof of XYZ theorem!"

JoeyBananas 5y ago

It's also not clear what this algorithm has to do with quantum physics. Maybe that's how it was discovered or it has applications to physics, but the algorithm itself doesn't require any advanced math or have anything to do with the wave function. It can be described using elementary combinatorics.

ArtWomb 5y ago

This gets brought up every time its mentioned. And I think its interesting. It's only tangentially related to actual physics. But parallelizing the WFC for large inputs might be exactly the kind of problem QC assists.

munificent 5y ago

It's reasonable to be surprised when a computer science term uses a metaphor, but I don't think it's fair to call it a poor name unless you also object to almost every other name in programming. Strings have nothing to do with textiles. And, very confusingly, they aren't even related to fibers or threads. Zippers aren't related to textiles either. Trees and bloom filters are not related to botany. Heaps and garbage collection are not about municipal waste management. Graph coloring, despite the term, has nothing to do with either pictures or pigments. Red-black trees aren't colored or botanical. Bubble sort does not involve fluid dynamics. Neither does bucket or cocktail shaker sort for that matter. Circular buffers are not round. You can't eat a spaghetti stack or poke your finger on a cactus stack.