this post was submitted on 12 Dec 2023
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[–] DudeBro@lemm.ee 107 points 11 months ago (7 children)

"observing changes the result" doesn't mean conciousness attempting to look at it changes the result, there is nothing special about conciousness (in quantum mechanics)

"observing changes the result" means we try to measure atoms and fields but unfortunately our measurement tools are also made out of atoms and fields which interact with the atoms and fields we are trying to measure, giving us a different result than if we don't attempt to measure it

It does bring up interesting questions about what the "real" behavior of reality is tho, since anything we observe is technically different than what it would be if left alone. We can only ever know what a slightly altered state of reality is

[–] agamemnonymous@sh.itjust.works 34 points 11 months ago (2 children)

Think of it like this:

You can use a tennis ball machine to measure how far away a house is by firing the tennis ball at a constant velocity, timing how long it takes the tennis ball to come back to you, multiplying that time by the velocity, and dividing by 2 (since you measured the distance for a round trip). This works pretty darn well for measuring the distance to houses.

But now try this same trick to measure the distance to another ball. When your measuring ball hits the ball you want to measure, it doesn't stay resolutely planted in the ground like that nice friendly house. The energy from your measuring ball bounces the ball being measured off into the distance. Even if you could get your measuring ball to return, the ball you measured isn't in the place you measured it.

Replace that tennis ball with a photon, and you have the basic picture. There's no such thing as passive observation. Measuring something interacts with that thing. Conventional measurement is like in the case with the house, the thing being measured is so much bigger and more stable than the thing we're measuring with that the effect is negligible. But once you start trying to measure something on the same scale as your measuring tool, the ensuing chaos makes it basically impossible to get useful measurements.

[–] chitak166@lemmy.world 4 points 11 months ago (1 children)

What happens if you try to cut a photon in half with a knife?

[–] agamemnonymous@sh.itjust.works 3 points 11 months ago (2 children)

The edge of a knife has to be thinner than the thing it's cutting, and we haven't found anything thinner than a photon

[–] chitak166@lemmy.world 3 points 11 months ago (1 children)

Clearly you haven't seen my penis.

[–] agamemnonymous@sh.itjust.works 13 points 11 months ago (1 children)

By that implication it's fundamentally impossible for anyone to see it.

[–] Wilzax@lemmy.world 1 points 11 months ago

I've found plenty of things thinner than photons, it's just that the photons they're thinner than are extremely low energy.

[–] TopRamenBinLaden@sh.itjust.works 3 points 11 months ago* (last edited 11 months ago)

This analogy is really well thought out. It really helps my brain understand the weirdness that goes on with measurements on the quantum scale. Thanks for taking the time to type it out.

[–] dalekcaan@lemm.ee 16 points 11 months ago

Every road leads to Plato's cave

[–] bouh@lemmy.world 8 points 11 months ago

My teacher had a good comparison for this: observing macroscoping reality like we do microscopic reality would be like throwing a car at another car to measure its speed or position. Obviously you alter the course of events this way.

Fortunately light doesn't do much in the macroscopic world, so we can use it to observe stuff.

[–] ProfessorOwl_PhD@hexbear.net 6 points 11 months ago

Not quite - observability in quantum mechanics is about the event producing an interaction that could potentially be measured, regardless of whether we actually attempt to measure it. By interacting with other things the superposition is collapsed and we can determine it's current properties, but it's still the "real" behaviour of things, because we can only determine things behaviours from their interactions with other things - not knowing what they do when left alone isn't just about there not being a human around to interacts with them, but about there not being any other particles - no atoms, no electrons, no quarks - for them to interact with either.

[–] chitak166@lemmy.world 3 points 11 months ago

Great distinction.

[–] morrowind@lemmy.ml 2 points 11 months ago (2 children)

What if you just measure the ambient particles

[–] Krauerking@lemy.lol 3 points 11 months ago (1 children)

Then you are measuring something with matter still and it then affects it. Literally causing interactions to measure means altering it's state even at a nonchalant glance.

[–] morrowind@lemmy.ml 1 points 11 months ago (3 children)

hmm, I can get how that might cause the measured item to say, change its velocity, but not how that would cause a wave to collapse into a single point.

[–] Krauerking@lemy.lol 1 points 11 months ago

Right but how do you measure the things around what you are trying to measure and get any data from it unless you expect them to also interact with the things you are measuring.

You have to have an interaction to measure even if you are measuring the outcome and steps away from the original interaction.

It's like measuring dark matter where the easiest way to prove it's existence was to wait and capture the decay of it but not the particle itself. But that means the particle was already gone when we got the measurements to prove it was there.

[–] Feathercrown@lemmy.world 1 points 11 months ago

It's not a physical wave. A wavefunction describes how likely something is to have different values for one of its properties. For example, an electron might have a wavefunction describing how likely it is to be in different locations. By observing if it actually is in a certain location or not, you force the electron to decide where it is concretely, "collapsing" the probability function into one value (its newly decided location).

[–] Umbrias@beehaw.org 1 points 11 months ago

Measuring is a loaded misnomer. Interacting with a particle changes what the particle is doing. There is no such thing as nondestructive testing in quantum physics.

Measuring just happens to be something we do a lot which necessarily causes particle interactions.

[–] Saeculum@hexbear.net 3 points 11 months ago (1 children)
[–] morrowind@lemmy.ml 2 points 11 months ago (1 children)

idk, I'm not a quantum physicist. I'm just asking theoretically

[–] wopazoo@hexbear.net 8 points 11 months ago* (last edited 11 months ago) (1 children)

That doesn't make any sense. Observation is alteration. You cannot see light without absorbing light.

[–] maccentric@sh.itjust.works 1 points 11 months ago

So would a blind person would also alter the outcome if they were in the position to absorb the light? You can absorb the light without seeing it.

[–] flan@hexbear.net 2 points 11 months ago

just measure everything from the same side it'll all get shifted in the same direction