7 ms·
Isn't the cat experiment bullshit outside of illustrating a macro version of this? Like, there's no superposition in reality or the cat is too big to be subject
by Obscurity4340 2y ago
Isn't the cat experiment bullshit outside of illustrating a macro version of this? Like, there's no superposition in reality or the cat is too big to be subject to quantum mechanics where these shenanigans happen or something?
- deleted 2y ago[deleted]
- hiciu 2y agoThe cat isn't in some quantum state. Cat is locked in a box, with some poison and a Geiger counter. Poison is released when Geiger counter registers a particle. Now, the process of atom decay that would be registered by a Geiger counter has some interesting properties and that's where the "quantum magic" happens. (at least, that's my mental model of it; ask an expert, I'm not an expert)
- immibis 2y agoThe quantum magic properties are thought to transfer to the poison and the cat.
- rcxdude 2y agothe idea is that everything is in some quantum state, because quantum mechanics attempts to describe everything. The thought experiment is basically going from the well-observed (and explained in theory) superposition of a nuclear undergoing decay to the never-observed (but still valid in theory) superposition of a cat being both alive and dead.
- Obscurity4340 2y agoWhy should it be valid in theory tho? What is the purported bottleneck in physical reality that is supposed to exist whose presence makes the Schrodinger cat thought experiment realistic? How does sentient observation get the ball rolling and why couldn't that happen in the absence of such observation at this scale?
- lupusreal 2y agoCat observes itself.
- IX-103 2y agoThat defeats the point of the exercise. The whole point was about the state of some isolated system. Otherwise we could say that the detector observes the state of the system without even needing the poison or the car
- megaloblasto 2y agoIt doesn't defeat the point of the exercise, it just shows that the exercise is nonsense. The cat is an observer therefore collapses the quantum wave function and is either alive or dead.
- baq 2y agoIn what sense the cat is an observer? Having eyes and a brain doesn't really mean anything in QM.
- lupusreal 2y agoIf the particle interacts, that collapses the superposition. Cats aren't any more or less blessed as observers than physicists. If either of them can observe the outcome, then both can.
- murftown 2y agoHmm. Maybe what "counts as an observer" is relative to your reference frame, and so is the concept of "superposition". And thus, though the cat is making observations within its environment, since the environment is sealed off, the cat is not "an observer" from our reference frame because there is no interaction between us and the cat. From the cat's reference frame it is probably not in a superposition - If it is observing anything, it is alive, and if it is dead, it is not observing anything. But if we observe the cat, the wave function is collapsed from our reference frame and the cat is in one or the other state. My understanding of quantum mechanics is pretty shallow so take this with an ocean of salt.
- ben_w 2y agoSchrödinger's thought experiment was supposed to demonstrate that superposition itself (and/or the whole of the Copenhagen interpretation) was a nonsense concept… but every test so far says it's real, that he was wrong, and that the cat would be in both states "until observed". But nobody knows what "observed" even means.
- gus_massa 2y agoThe problem is to isolate the box enough. If you can heard the cat meow, then it counts as a "measurement" and the superposition disappears. If you can hear there is no heartbeat of the cat, then it counts as a "measurement" and the superposition disappears. If the cats move and the box wags, then it counts as a "measurement" and the superposition disappears... So in practice the experiment only works with very small systems with a few atoms. Each year there are experiments with bigger systems, but they are usually frozen and very small. Perhaps one day we will be able to do the experiment with tardigrades.
- Vampiero 2y agoHearing at all implies sound waves. If there are soundwaves there is air inside the box. If there is air inside the box the system can't be in a superposition because it has long since decohered. In other words it's not the act of "listening" that collapses the wave function but the interaction of air molecules that creates the sound in the first place, even if no one is there to listen. A "measurement" or an "observation" doesn't actually require a human, or a living thing. It's just a physical interaction.
- rvbissell 2y agoCatch 22: and if there is no air inside the box, then you are certain the cat is dead.
- Maxatar 2y agoThis isn't quite right, wave function collapse is relative so while within the box an observer's wave function of the box will be in a definite eigenstate, the wavefunction of the box for an observer isolated from the box will still be in a superposition of its states. In other words, the fact that an observation takes place from within the box and collapses the wave function for an observer in the box does not mean that the wave function for every observer also collapses. A wave function collapse for one observer does not imply a wave function collapse for any other observer.
- 2y ago
- ahazred8ta 2y agoSchrödinger never believed it; he gave that as an example of something that could never happen in real life.
- sebzim4500 2y agoAs far as known physics goes, nothing is too big to be subject to quantum mechanics. It is very hard to demonstrate that fact though, the obvious way of doing it is to build a large quantum computer.