Anytime I read about it or when I hear people using it to describe a situation I feel stupid as shit. And how is it can be used to quantumcomputers?
Help a dumbass out. Thanks.
In: 39
So quantum mechanics are very weird.
A lot of times systems of very tiny particles behave as if they’re in many different states at the same time until we observe them. When we observe them, they seem to only be in one state. This “being in many different states at the same time” phenomenon is called superposition.
Schrodinger’s cat is a thought experiment to demonstrate how the weirdness of superposition doesn’t really gel with what we observe in the macroscopic world.
The thought experiment links something we can directly see exhibits superposition, a radioactive nucleus decaying, to whether or not a cat gets poisoned, which we really consider to not be a situation where superposition applies.
Schrodinger’s cat is a thought experiment in which a cat is put in a box with a decaying isotope. The radiation produced is guaranteed to eventually kill the cat; but since the cat is in a box, you can’t know for certain if the cat has died yet until it’s opened. Effectively, until the box is opened and you can see for yourself, the cat is both alive and dead.
Situations that must be confirmed are often compared to this. For example, if you apply for a job and receive a decision in an email, until you have read the email it can be said that you have both gotten the job and not gotten the job.
Schrodinger’s cat isn’t a theory exactly, it’s a thought experiment that was made precisely to show how weird quantum mechanics could be.
The basic premise is that there are different states that a quantum system can have, we’ll call them A and B, but that there is also a weird quantum situation called “superposition”, where you aren’t in A or B, but a combination of them that is determined by the relative probabilities of A and B.
Schrodinger’s cat takes that, and scales it up to a regular size. You have a box with a cat, a bottle of poison, a Geiger counter attached to a hammer, and a single atom of a radioactive material. If the radioactive material decays, then the Geiger counter clicks, swinging the hammer, releasing the poison, and killing the cat.
Radioactivity is one of the situations where a superposition can happen, where you have the two final states, “decayed atom” and “not decayed atom”, but the quantum weirdness introduces the third superposition state of both decayed and not decayed.
So the cat is now also in a superposition, being both alive and dead at the same time.
When you get into Super Crazy Physics, there’s a theory that says a thingie can be simultaneously Possible State 1 *and* Possible State 2. Whenever it interacts with something, *then* it becomes either Actual State 1 or Actual State 2 – but until then, it’s *both* possible states at the same time.
Weird, right? A physicist named Schrödinger also thought it was weird. He came up with an example of just how unlikely he thought the theory was. He said: “So OK, you’re telling me that if there’s a cat inside a box, and there’s a device inside the box that will either kill the cat if it goes into Actual State 1 or let it live if it goes into Actual State 2, then if nothing opens the box to interact with it the device is in *both* Possible State 1 *and* Possible State 2? But that means the cat is both dead *and* alive simultaneously until we open the box? What the fuck, you guys? This idea is dumb.”
Over time, it became misunderstood as him using the “cat in a box” to *explain* the Super Crazy Physics when actually it was him facepalming at the idea.
Erwin Schrodinger was one of the founding fathers of quantum mechanics. He along with many other scientists were breaking new ground on the regular, and as a consequence of that, they were discovering and conceptualizing all sorts of newly-discovered concepts.
One of these was the concept of “superposition.” In the quantum realm, if a particle may exist in many different states, it acts as if it exists in a sort of sum total of all those possible states. It takes a “superposition” of all those different states, and it remains in that superposition until it “collapses” into a single state due to some interaction with an observer or its environment. Just the act of measuring the particle will collapse the superposition.
This is, of course, hugely unintuitive because things in our human-scale macro world do not behave like this at all. They behave classically, as if they only ever have one state at a given moment. So something like “superposition” was just as unintuitive to Schrodinger as it is to you and me.
Schrodinger proposed the cat as a sort of thought experiment to criticize the absurdity of superposition. He proposed that you put a cat in a box with a device. The device monitors the nucleus of an unstable atom, and if/when that atom decays, the device will spew out poison gas, killing the cat. Now, outside the box, we don’t know whether/when that atom decayed–and by extension we don’t know whether the cat is alive or dead–until we open the box. If we played by quantum mechanical rules, the cat is both alive AND dead until we open the box to check, at which point the quantum supercat collapses into a regular–living *or* dead–cat. Now, we know that cats don’t exist in a living-and-dead superposition, so this thought experiment is intended to poke at the absurdity of the concept.
We now know that superposition *is* in fact how things work on those very small scales, (and we know that the thought experiment isn’t apt for a number of other reasons) but Schrodinger’s cat has become a colorful illustration for a lot of day-to-day scenarios involving chance and decision-making.
Schodinger’s cat is like a shower thought, musing on the difference between the world we observe and think we understand, and the quantum world.
If you put a cat in a box with a vial of poison that might be broken at any time, you won’t know until you open the box if the cat is alive or dead. But as far as we know, at any point in time, the cat is either still alive, or already dead, even if we don’t know it. It’s state (as far as we know), is what it is, independent of our knowledge.
However, if the cat were a quantum particle, then it would be in both possible states until we opened the box, and wouldn’t actually be dead or alive until we looked inside the box, at which time it would instantly be either alive or dead. It’s state only seems to resolve itself when we check it out, and up until then it seems to be in some combination of both or neither.
Well a few years earlier, Niels Bohr and Heisenberg came up with the theory of “Copenhagen interpretation” about quantum mechanics.
Which both Einstein and Schrödinger didn’t really agree with, because it didn’t fit according to them. So eventually Schrödinger came up with a thought experiment to disprove Niels and Heisenberg. So the thought experiment is a way to easier help others understand why the Copenhagen interpretation doesn’t always hold up in reality. The thought experiment;
Imagine that you put a cat tied down (as to not mess with the experiment) in a box along with a Geiger-counter(measure radioactive particles), a tiny amount of radioactive substance which has a 50/50 chance of decaying or not decay within one hour, releasing radiation. The Geiger is rigged to when as soon as the atom decays, it’s radiation is detected. Then the Geiger rig releases a hammer that smashes a bottle of poison and kills the cat.
According to Bohr’s and Heisenberg’s theory, after an hour the cat will be both dead and alive at the same time until you open the box and observe it. SOOO basically Schrödinger came up with this idea to show Bohr( and the rest of the academics) how absurd the Copenhagen interpretations is in reality when scaled up a bit. And that it is a huge flaw in his theory.
Well this is my amateurish interpretations of it all at least, please correct me if I’m wrong since it has been many years since I read about it. But I do remember that a lot of people misunderstand the point with it all and I did as well before I saw a documentary when they talked about it and explained it really well.
// Mímir
Schrödinger’s cat is a thought experiment that helps us understand a weird idea in science called quantum mechanics. The experiment is about a cat that is in a box with a poison that might kill it. We don’t know if the cat is alive or dead until we open the box and look.
But here’s the weird part: in quantum mechanics, it’s possible for the cat to be both alive and dead at the same time, until we open the box and see what’s inside. This is called a “superposition” and it’s just one of the strange things that can happen at the very small scale of atoms and particles.
So, even though it sounds crazy, Schrödinger’s cat helps us understand how the world works on a very small scale. It shows us that the rules of science can be weird and counterintuitive, and that there’s still a lot we don’t know.
Often times the cat gets conflated with wave v particle malarkey. Do not believe it. It has to do with super position of sub atomic particles and the inability of the humans to make reliable measurements on a sub wavelength scale. There is no Eli5 because the math involved for even a surface level understanding of the quantum level is not easy to communicate.
It’s a theoretical, to help us try to comprehend.
Akin to the paradoxes of philosophies of most every developed thought of all cultures.
Those who ‘explain’ it to you, or claim to have irrefutable truths, are ‘frontin’. Don’t sweat it.
Just learn, unjudged.
It’s a tool to seek answers, not an answer itself.
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