Why is this whole post about photons? I always thought that the double slit experiment was interesting because this happened with electrons, even individual electrons would still generate the interference pattern, and I guess I always thought that you could detect which slit the election went through by detecting an induced current or something
They talk about how it was never actually possible to do this before, because it requires very fine “electron optics” and manufacturing of components, like slits and shutters, with nanometer precision. So while the thought experiment with electrons itself was proposed by Feynman in 1963 (which is probably what inspired the monkey meme and the like), it was not actually realized until 2019. I’m also now guessing that the electron quantum eraser paper from 2014 doesn’t use a double slit but some other electronic quantum circuit that is easier to work with.
The two-stripe photo to match the monkey meme, with electrons and measuring which-way information, probably doesn’t exist yet. So that’s why!
Yes, double slit interference happens with both photons and electrons, and even with C60 buckyballs and organic fluorescent dye molecules (arxiv.org/abs/1402.1867)! This post is more so about the quantum eraser, as a counterpoint to the 12 posts about it that @kromem wrote in the other thread. The first experimental quantum eraser paper from 2001 uses photons, so that’s the figures I used here. There might be newer papers that use electrons, like this one doi.org/10.1126/science.1248459 from 2014, but I don’t have access to it. I presume detecting the electron there using induced current or whatever would disturb its wavefunction to the same severity as using the polarizer filter does here.
Holy smokes! I always thought it just showed that electrons and photons aren’t ‘really’ particles, I had no idea it also worked for atoms and even molecules.
As someone who enjoys quantum mechanics, but papers are too far over my head; and has struggled with a nagging sense that something about all the explanations just wasn’t making sense, thank you for this beautifully clear explanation of how these conclusions were reached.
So it turns out the original meme was kind of right? It just didn’t illustrate what it was talking about very well. According to @ada@lemmy.blahaj.zone:
The double slit experiment is about observation.
When you fire photons through the double slits, one photon at a time, they cause wave interference patterns with themselves as if each photon travelled through both slits.
Yet if you set something up to measure which slit each photon passed through, they no longer interfere with themselves, and give you the two straight lines pattern, rather than the interference pattern.
In this experiment, they didn’t even bother measuring which slit each photon passes through. The 3D glasses don’t measure or observe the photons, they merely polarize them (although they do block 50% of light). The detector D_S doesn’t measure which-path information either. The researchers could have placed a circular polarizer in front of D_S, and when they get a hit they could have said with confidence “this photon came through the top slit!” but they didn’t even bother doing it this time. The fact that the 3D glasses alter the light in a manner which makes the which-path information theoretically measurable (even if not actually measured), alone is sufficient to destroy the interference pattern.
The original meme is definitely correct, idk why so many people were having conniption fits over it. In the double slit experiment’s simplest form, not measuring the photons leads to the wave interaction pattern and measuring the photons leads to the two bars as you’d expect from particles.
And since physicists decided to use the stupidest term possible to describe that measurement, the monkey “observing” the experiment is a play on what the actual experiment is doing
It’s clear he’s observing something, but all too easy for the viewer to think the monkey is merely observing the pattern on the screen at the end. It also doesn’t help that there are a bunch of slight variations on the double slit experiment, like those listed in this post.
If the monkey was at 90 degrees to the experiment, looking at the slits only side on, then it might be clearer - though I’m not sure how you could draw that lol.
Disproportionate energy expediture. Little effort for magic mans big effort for science mans. I’d love to move earth around me effortlessly and I only occasionally like flinging dirt around with a shovel.
People will always optimize their methods to maximize resource gain. It’s a fact of life since the dawn of life. Even animals do this.
I’ve seen cancer researchers lie to people with dead loved ones to get funding. I’ve seen physicists do bogus experiments that yield nothing with a nice dark matter story just to get funding… it’s become marketing at this stage.
This is my problem with climate change research. Those who attempt to oppose the “narrative” never get funding. How are we supposed to claim science is unbiased when bias is what’s making the results come out?
Brilliant. Do you call this quantum consciousness, quantum mind or something? At least in German its Quantenbewusstsein. After all these years i remember that photons notice you observe them and behave differently, because it’s ducking interesting.
science_memes
Hot
This magazine is from a federated server and may be incomplete. Browse more on the original instance.