Can anyone explain why these two arrangements are not equivalent? They seem to both cause same phase shift and reflections, but the first one causes the photon to pass to the right, and the second - to split.
Quantum Game with Photons
31–40 of 53 posts
Re: Quantum Game with Photons
#32I am stuck at 25, 31 and 34. Does anyone has a cue ?
25.1-25.2: Avoid the left bomb first. Cut the right bomb risk to 50%.
25.3-25.5: Photons don't care about the direction of time. Fire one backwards in time from the detector to the emitter.
31.1-31.2: To avoid the bomb, the light must be polarized horizontal ASAP.
31.3-31.4: A sugar and a rotator in series, or a rotator and a mirror will preserve polarization going one way and rotate 90 degrees the other way. You may have to flip the rotator over by clicking on it.
31.5-31.9: Go backwards from the detector to figure out where the polarization has to be horizontal, and where it has to be vertical. You never need to consider interference.
34.1: Without rotating the polarization somehow, you'll never get enough photons through the filter.
34.2-34.3: Avoid hitting the rock and the top bomb.
34.4-34.5: You only have one option left for reflecting away from the bottom bomb. And you'll need vertical polarization to use it.
34.6-34.8: You can only absorb 25%, and it should be obvious by now which path you have to absorb from. Now arrange glass and vacuum to produce the correct interference.
Re: Quantum Game with Photons
#33Author here. Really excited to see Quantum Game on HN! :) Just in case, project repo is here: https://github.com/stared/quantum-game For more on learning (and teaching) quantum mechanics, see: http://p.migdal.pl/2016/08/15/quantum-mechanics-for-high-sch... And BTW: a question to you (as I guess there are many JavaScript whizz kids): how to make it more reactive?
Thanks for the game. I am playing through the levels and it is a lot of fun. But so far I have not found an effect that cannot be calculated with the classical Maxwell equations in matter.
A single photon QM is basically classical wave mechanics.
My original intention was to do many-photon QM game (and wrote game engine for that). But in development I discovered that even wave mechanics offer quite a lot interesting, and counterintuitive, puzzles.
With one photon there the only thing that does not have a classical analogues is https://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb_t..., which can be easily assembled from the blocks (well, the idea for using a light-sensitive bomb comes from there!).
Re: Quantum Game with Photons
#34Can anyone explain why these two arrangements are not equivalent? They seem to both cause same phase shift and reflections, but the first one causes the photon to pass to the right, and the second - to split. https://imgur.com/a/OkEQY https://imgur.com/a/Byo8E
Reflection changes "left-right". So effectively, a sugar solution (rotating polarization) before mirror rotates it in the opposite direction (vs a sugar solution after a mirror).
Actually it is a tricky thing I realised while testing this game. I thought it was an error in code. But nope - it was how does physics work. :)
Re: Quantum Game with Photons
#35I can't really make sense of interference. I made it to level 6, but I didn't understand the solutions for any of the 3 previous levels. I found some of the online help, but I'm not really making any sense of what it's saying.
This game isn't writing the numbers (complex-valued probability amplitudes of states, classical EM vectors even) anywhere so it's going to be pretty hard to relate what you're seeing here to the math that you'll find if you look up interference elsewhere. I'll make an attempt here, though. I think the effect on level 4 is totally classical so it shouldn't take too much background. 1. The solution to a problem involvi…
Thanks for the great explanation! If you don't mind, I had a question about '3.' I get how it's used in making your larger argument, but as a thing in itself I'm kinda lost. Part of what I'm wondering is how it's okay to say 'L(W) = 0' when earlier you described L(W) like 'L(W: wavefunction) => X: wavefunction'; so is the zero in 'L(W) = 0' just shorthand for something like 'L(W) = (f(x,t) = 0)'?
(I'm also curious why mapping to the zero function ends up being the central criterion for physical possibility—but I'm guessing that's a rather deep subject ;))
Edit: NVM I see what's going on with 'L(W(x,t)) = 0' now: the equation is equating the full evaluation of the nested functions on the left (using the x,t params) with zero. When written like 'L(W) = 0' it looks like it's equating the function returned by L(W) with zero.
Re: Quantum Game with Photons
#36Re: Quantum Game with Photons
#37Author here. Really excited to see Quantum Game on HN! :) Just in case, project repo is here: https://github.com/stared/quantum-game For more on learning (and teaching) quantum mechanics, see: http://p.migdal.pl/2016/08/15/quantum-mechanics-for-high-sch... And BTW: a question to you (as I guess there are many JavaScript whizz kids): how to make it more reactive?
found a bug: if i click next after completing a level before the "you won" screen pops up and subsequently click next level on the "you won" screen i can skip two levels ahead
Re: Quantum Game with Photons
#38Vertical and horizontal here seem quite confusing. The absorptive polarizer with vertical lines drawn on it passes through photons passing through PBS, which game calls horizontal. So either the polarizer lines have negative logic (indicating what is absorbed, not passed through), or there is some inconsistency. Similarly, the horizontal polarization is represented as photon bouncing up and down ("vertically") if it…
I admit I had a big struggle with visualizing polarizers. It is easy to do in 3D or some 2.5D. In 2D every visualization was confusing (the one we use is the least confusing).
Any ideas are welcome here (as long they work for every possible orientation and are 2D).
Re: Quantum Game with Photons
#39I can't really make sense of interference. I made it to level 6, but I didn't understand the solutions for any of the 3 previous levels. I found some of the online help, but I'm not really making any sense of what it's saying.
This game isn't writing the numbers (complex-valued probability amplitudes of states, classical EM vectors even) anywhere so it's going to be pretty hard to relate what you're seeing here to the math that you'll find if you look up interference elsewhere. I'll make an attempt here, though. I think the effect on level 4 is totally classical so it shouldn't take too much background. 1. The solution to a problem involvi…
If you turn on the JS console, you will get quantum state printouts (with all nifty complex numbers and polarization vectors).
Re: Quantum Game with Photons
#40As a physics student I always hated quantum optics. IMHO the by far least intuitive field in undergrad physics. I never got. Not even a bit. Circuits, Special relativity and quantum physics in the context of atoms was so much more approachable to me. I mean, I like physics. I wonder why optics is so different.
In the end all I did was learning some standard configurations of optical instruments. That and ray optics made me pass. Of course i forgot almost everything almost instantly.
I really love the idea to get a better intuition for what is going on by a game.
By level 30 I thought I understood how the Faraday rotator works in this game. In level 32 I feel like my solution should work, but it doesn't. It behaves completely different that I think it should. The help page don't help me at all.
I'd like to see some "debug" mode where I can freeze time and inspect the quanta.
Also I feel that the simulation sometimes "gives up" too early, and i can't see why something isn't working because it ends too early.