Observer

This sort of comic always bugs me. Observation in QM is not the same as observation in layman terms.
Best think of it as hit it and watch the pieces fly. When you get small enough, you can't approximate out the impacts. It's akin to studying road traffic by sending an overloaded freight truck the wrong way and counting tires that hit the verge. It might also affect the current traffic's motion.
- This is something that I noticed is hard to understand to most people. My SO got served a video of the double slit experiment and thought it was like magic, until I tried to explain to him that at this scale, "observing" doesn't just mean looking at it. Observation makes you part of the system and causes the system to change.
  
  That is part of what bugs me.
  Quantum mechanics isn't magical or unknowable. It's just an area of physics where some of our base assumptions/approximations break down. It's not even that hard to wrap your head around, it just seems most people don't want to try.
  
  There is a magic to perception nothing else can replicate. I'm pretty sure awareness is existence, so it's attention has to change reality.
- Tbh, I think no one who hasn’t solved the Schrödinger equation at least once (at least time independent), should be allowed to talk about quantum.
  Like, the uncertainty principle is really really fucking cool when you understand why it works mathematically. But without differential equations and linear algebra, I don’t think it’s possible to really conceptualize what’s going on in quantum.
  Idk, I always try to explain to students the deficiencies of the Bohr model and explain the significance of the electron cloud, but probability is hard.
  One of my favorite things in quantum was deriving the “quantum numbers” they have you memorize in chemistry (if you don’t remember, you probably got a SPeeDy F) It’s beautiful to watch the way they emerge from the second order diff eq.
  
  While I'm rusty as hell, my physics degree was actually focused quite a lot into QM.
  It's perfectly possible to get a reasonable understanding of what's going on without going head first into the maths. There are definitely areas however that we don't have a good conceptual model of yet. For those, the maths definitely leads the way. 90% of QM is comprehendible with relatively little maths. You only need the maths when you start to get predictive.
- You're right. But the thing that's interesting about the double slit experiment though is that it works on only a single photon. It's as if all the traffic was created by a single car. So classically you might not think that the single car should care if the freight truck is heading down a different lane than the car but in QM it does, because the car is in a superposition of occupying several lanes.
  I'm probably driving the analogy straight into the ground of course
- Which is what's so "magical" about it - Newtonian rules seem to break down at the quantum level.
  It was an incredible discovery, and for practically anyone not a physicist, it's incredibly hard to comprehend. I say this as a not-a-physicist who struggled to comprehend it decades ago, and read several books on the subject to finally get my head around it (as much as a non-physicist can).
  Also, it's just a meme mate.
  
  I disagree with it being hard to comprehend. The maths is an absolute bitch, but the basic premise is fairly simple. Everything is (quantised) waves. The rest clicks, once you get your brain to accept this. Everything else is a consequence. Those consequences can lead you down deep dark tunnels, filled with evil maths and mind bending results, but the basic idea is simple.
  I have a bit of an issue with memes that are actively misleading.
- psssst, it's just a meme
  
  Lots of folks get their superficial education from memes and will be mislead by this...
  
  So was "Donald Trump for president" and look at the damage that has caused.

Can't blame them I also try to act normal when people is watching.
- I'm not weird. I act perfectly normal when no one is watching. honest.

Wait, but we're looking at it...
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I have been tryin to find an actual demostration of this experiement and it seem impossible to find. can someone sow me this experiment done on a single setup. where you have a light source, two slits a screen and an ''observer''. That swithes from interference pattern to two lines, by switching the observer on and off. I am convinced that the science is solid, in its theoric and applied aspect. but that this interpretation of it is complete bullcrap. And i am annoyed by the ''believe this cheap explanation''that is repeated and nauseam. What is the actual equipment required, wave lenghts, slit sizes. I know This is science meme sub, where is the sub where i can find an actual two slit operator?
- Physicists calling it an "observer" is the worst thing since Ben Franklin decided to name positive and negative electrical charges. "Observer" implies that it's someone watching the thing, when really it's just the light interacting with something.
  
  Yes, that's what bothers me about the whole thing. All those ''popular science'' exposé telling us that if you just look at it, it will know and change from wave to particle. They put this big eye icon next to the slit and imply you are stupid if you dont just believe it as told. the experiment with polarized filter someone else showed me was interesting, but that's not merely observing.
- https://en.m.wikipedia.org/wiki/Double-slit_experiment
  Put a filter on one slit to measure the beams. Done.
  Edit: this thinks about a related experiment, where you build an interferometer instead of a double slit. Now rephrase the experiment s.t. you have to beams serviced from a singular beam. interfere the two beams with each other. If you measure on one beam path (e.g. Pol filter) you destroy the interference pattern.
- What are you trying to see exactly? There's this video done with polarizers: https://youtu.be/unCXuRXpEhs Of course, it's not an instant on/off but having an instant on/off doesn't really change anything.
  
  Thank you. Yes something like that. with lab grade equipment would be nice. I agree instant on/off is not required for my understanding.
- You can put together a version good enough for high schoolers with a laser pointer and some pencils.
  To conceptualize though, it might be better to set up some sort of wave table - some sort of tub of water you set up the slits in, then observe the patterns of constructive and destructive interference. (That’s what I did with students.)
  
  Yes, thats a very easy demonstation of the wave nature of light, what bugs me is the demonstration that it's also a particle that I feel is misleading. Maybe particle is not the right word to describe it's nature.
- You don't really need an on/off switch.
  By default you are not observing what slit it goes trough so you should always see the wave pattern.

Yeah they beamed with pride when asked about their work. They were so observant and laser focused and we hit the mark every time while they were here. It was pretty obvious they'd make waves when they quit. Still, no one expected it.

This makes me pretty annoyed, mostly because I get flashbacks to assholes pushing The Secret

Attractor

Thanks lemmy user!