Think of it like this…a photon is both a wave, and the smallest discrete unit of energy
When the wave is absorbed by something, the energy must be transferred. But the smallest unit of energy is the full photon, and so the full amount of energy of the wave is absorbed at a single point, because there’s no such thing as partial photons
Or in other words, the wave doesn’t turn into a particle, the energy gets spent at a single point in space
Really, I think all of quantum physics works like this. Electrons don’t exist as a point in space, they exist in an area. They’re fields, they’re not necessarily moving fast, which is why atoms don’t randomly slip through each other and we can’t measure all the properties of it at once
AppleTea@lemmy.zip 1 day ago
oh boy, here I go banging this drum again:
When physicists say “observe”, they actually mean “measure”. And to measure a photon of light, you have to interact with it somehow, there is no passive way to do so.
The post’s header image implies that the interference pattern goes away just by looking at it. If that were the case, we would never see the interference pattern, never know it was there in the first place! In the actual experiment, they put a sensor at one or both of the slits. But to “sense” a single photon, you have to interact with it in some way. Otherwise you wouldn’t know it was there.
Again, this is where the language trips us up. Rather than “sensor”, would really be more accurate to say they put a photon-touch-er at the slits.
So, what we actually get is “Touching the photon changes the photon’s behavior.” The universe doesn’t magically infer when we happen to be looking at it, there is no spooky action-at-a-distance!
bilouba@jlai.lu 17 hours ago
Sorry but you are wrong. This is how I understood it too, but this is way weirder. Look into quantum eraser or polarization experiment. Information cause the wave collapse. You can use another set of polarization at 45° to activate the interference pattern again. It goes beyond physical perturbation and it has been demonstrated by experiment. I’m not a scientist and this is fairly new information to me so I can’t explain it to you very clearly I’m sorry, but trust the science, things get weird at the quantum scale. Intuition doesn’t work at this level.
VoterFrog@lemmy.world 9 hours ago
I don’t think it’s wrong, just simplified. You don’t really have to touch the photon, just affect the wave function, the statistical description of the photon’s movement through space and time. Detectors and polarizers, anything that can be used to tell exactly which path the photon took through the slits will do this. Quantum eraser experiments just show that you can “undo the damage” to the wave function, so to speak. You can get the wave function back into an unaltered state but by doing so you lose the which-way information.
bilouba@jlai.lu 2 hours ago
It really is about information and coherence and is really hard to explain and I’m not qualified to do it. For me the polarization show that it is beyond touching anything. You can use the first pass of filter to aquire information and it break the interference. But then you can use a second pass to remove this information and get an interference back. The photon was “touched” by both filter, so how come interference get back ? A photon is not the same as light (many photons) so you can’t really apply electromagnetic reasoning to the quantum world. Sorry to do an appeals to authority, but it’s been literally 100 years since the discovery of this science and if it was simply like space time and electromagnetic waves it wouldn’t be know as this really weird and unintuitive model that works on really small scale. You can create a pair of photon and observe their linked property even kilometers apart when they collapse. It weird, but having information about the system, change it. Of course it’s not literally like this meme. But again, I’m not an expert or a scientist, so if you know more, please correct me.
474D@lemmy.world 1 day ago
But then what is the significance of this experiment? Why is it so popular if it’s that simple and why is it usually associated with quantum physics?
abfarid@startrek.website 1 day ago
If not touched the photon goes through both slits and interacts with itself, which is still super weird. Basically, it’s a wave if not touched, but a particle if touched.
Gremour@lemmy.world 1 day ago
Which suspiciously reminds optimization. Like computer game with infinite procedural world, where map chunks only generated where player interacts with world, being just formula (algorithm) everywhere else.
Agent641@lemmy.world 18 hours ago
Photons exist at the edge of our dimension, not really a part of it, but skimming the borderlands between dimensions. Like a bug on the surface of a lake, it influences the lake and the atmosphere simultaneously, can be inferred by its effect on the lake, but it cannot be observed (eaten) by a fish without also fully entering the lake dimension. In this borderland state the photon has the theoretical potential to influence many dimensions, but doesn’t belong to any one of them. Measuring, or touching the photon turns that potential into causative certainty where the photon is now part of our dimensions’ event chain, pulling it fully into our dimension to the exclusion of all others and converting it from a probabilistic multidimensional potential into a deterministic unidimensional particle.
I just made all that up but it sounds pretty good IMO.
Johanno@feddit.org 21 hours ago
Well yes’nt I say a vertasium video and he explained it a bit differently. However I still didn’t understand it. But they show the effect in different ways so it is easier to understand.
www.youtube.com/watch?v=qJZ1Ez28C-A
Iunnrais@lemmy.world 1 day ago
I’ve asked this of a physicist friend of mine, and he insisted there wasn’t actually photon touching being involved. I honestly didn’t understand his explanation fully though. Photon touching makes sense to me. Whatever he said was much more confusing… yet he gets grant money to actually study lasers and put out research papers, and I don’t, so…
AppleTea@lemmy.zip 4 hours ago
“Photon touching” was a somewhat glib way of putting it on my part.
What does your friend think of this statement:
Iunnrais@lemmy.world 4 hours ago
No, that exact thing, interacting with the particle, is what he was saying does not happen, or at least is not required for the effect to happen. This is where his explanation lost me, because my understanding had aligned with yours, and he spent a good half hour trying to explain how I was wrong, and to be honest, it didn’t quite sink in.
I remember there was a lot of math in his explanation, and multiple different interpretations and angles of understanding — but my takeaway was just that he strongly claimed no interaction with the particle whatsoever was required for uncertainty and the weird particle/wave dichotomy to take place, and that experimental evidence has been provided for this. Furthermore, that I have no fucking idea what observation means, but it doesn’t apparently mean interaction with the particle at all.
anon@lemmy.sdf.org 1 day ago
So what’s surprising about the experiment?
Of course, when you interact with things they change
davidgro@lemmy.world 1 day ago
As another comment said, the wave behavior when not measured is hard to explain if one thinks of photons as little particles that classically would need to go through one slit or the other. It seems each one goes through both slits and self-interferes.
And when measured, sure enough they act like little particles that need to go through one slit or the other.
Nurse_Robot@lemmy.world 1 day ago
Thank you:)