Comment on Observer
cynar@lemmy.world 1 year ago
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.
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 I’m 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.
Well, famously, they’re waves and particles. The double slit which way experiment will only set off the detector in one slit, as if it was a particle. Yet, without a detector it will interfere with itself as if it were a wave that passed through both slits.
QM entities are quantised waves. You can make a wave look very close to a particle quite easily, a particle can never behave like a wave.
Dumping the mental short hand of particle interactions is one of the main reasons most people can’t get their heads around it.
psssst, it’s just a meme
So was “Donald Trump for president” and look at the damage that has caused.
Lots of folks get their superficial education from memes and will be mislead by this…
well that’s their own fault, and it’s not like stuff like this is vital information for the average person
Specifically, because it’s non-vital information for the average person, I really do not think you can blame anyone for merely learning about it through memes. But I do also think this problem is much greater than just memes. I did not receive a better explanation during high school, despite opting for more advanced physics classes and us repeatedly telling our teacher that it makes no sense to us. I have to assume that our teacher did not know either. As such, I got the impression that more advanced physics is just devoid of any actual logic, which was a major factor why I decided against pursuing it further in college. Reading a proper explanation under a stupid meme, could’ve made the difference for me.
So why are you so upset with us trying to fix it?
I personally find the anti science, anti learning crowd has gone from amusing, to annoying, to terrifying.
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.
Quantum mechanics is an area of physics that leans on measurement as a central concept. What things are doing between measurements is not its’ concern, and don’t even stop and think about it, you’ll go nuts, just shut up and calculate!
Magic is just stuff we don’t know but don’t care to know :)
No, it’s not. Magic isn’t real.
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.
“Observation” in a QM sense has nothing to do with sapience of anything like that. It literally just means that something needed the information and it collapses the waveform. It’s any time it influences another particle. It doesn’t matter what that particle is. If it needs to know the state or the particle we care about then it “observed” it. Humans or animals need not be involved.
Perception and observation are different things. Air molecules can be “observers” when looking at electrons etc.
I think we need to build a time machine to go back to Atlantis, to kill Ramtha and make sure that What the Bleep? never gets made.
andros_rex@lemmy.world 1 year ago
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.
cynar@lemmy.world 1 year ago
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.
andros_rex@lemmy.world 1 year ago
I don’t think you can get the intuitive feel/the “why” without the maths.
I guess I get frustrated when I have to teach algebra based introductory physics for similar reasons - everything makes so much more sense when you understand how the pieces fit together. (Why make them memorize d=d0+v0t+1/2at^2 when all that is integrating a constant twice? That you can set v=0 to find the time of maximum height, because you’re using a derivative to find a max! And then that helps you get why it works, and then even how to possibly explore non constant acceleration!)
I got really fucked over because I didn’t take linear (at all - advising in my physics department was non existent which lead to things like taking classical before Diff Eq lol) and so things like eigenvalues - which tbh I think is kinda the money shot - that things end up quantized and discrete - that took a while for me to get what that meant.
someacnt@sh.itjust.works 1 year ago
I find QM quite confusing, in that one can observe only the eigenvalues and not the state itself. Why is it specifically, or is this wrong conceptualization? Also, how does particle-ness relate to the eigenvalues?