# Schroedinger's cat

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In this thought experiment a live cat was placed in a box with some device which could render it live or dead after some specified time. Schroedinger noted that the device's outcomes could be represented mathematically (his wave equation). Because the outcomes of the equation are "indeterminate" (unknowable until known) he suggested that the cat's status was indeterminate and it was in a "superposition of states" that is, neither live or dead.

Do you think that

(a) Schroedinger was trying to point out the absurdity of applying QM to the world in which cats live

or

(b) you know the physical process whereby a live cat can be rendered neither live or dead by being placed in a box

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a.

If whatever event that kills the cat happens, and the cat were left for a long time, it would start to decompose. Obviously it wouldn't really be in a superposition of states until you lifted the lid.

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a) The cat knows whether its dead or alive.

Its a bit arrogant to prosume if we cant see a cat there are therefore infinate universes (missing a few steps iknow)

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If whatever event that kills the cat happens, and the cat were left for a long time, it would start to decompose. Obviously it wouldn't really be in a superposition of states until you lifted the lid.

The cat according to Schroedinger IS in a superposition of states while it's in the box. Started live, then into box, then after a short time either dead or alive.

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I belive the taken form of death is radioactive isotope, as radiation is random the time is unknown, so placing the cat in the box and closing the box the cat could be dead from the radiation and is dead in some universes (if you belive in multiple universes that is) whereas in other universes the cat is still alive as the radiation is yet to kill it due to it's randomness. We do not know whether the cat is dead or alive untill we open the box.

QM is absurded it has been commented on many times that if you think you understand QM then you are just fooling yourself.

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(a) Schroedinger was trying to point out the absurdity of applying QM to the world in which cats live

Or, stated more generally, the absurdity of applying QM to macroscopic events.

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Maybe I missed the point, but wasn't the superposition of the cat simply reffering to the impossibility of predicting the outcome? When you open the box, the cat will be dead or alive, possibly dead for some time. But even if the cat is dead, you have no way of knowing the state of the cat unti the box is open and the cat is observed.

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'']you have no way of knowing the state of the cat unti the box is open and the cat is observed.

Agreed. But to me that suggests a difference between knowing the state of the cat and what state the cat is actually in (irrespective of our knowledge). Now, it may be the case that for quantum events there is no actual until there is knowing but does this apply to cats?

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I think not - well, not exactly. It is the act of opening the box and observing the contents which collapse the associated waveforms. I'm with ed84c on this, however, the cat can collapse its own waveform through self observation. I've discussed this with my own cat and she assures me she would notice if she were dead!

(Did Schroedinger choose a cat rather than a dog or rabbit because of their nine lives? This would allow the experiment to be repeated several times with the same cat.)

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Ahh...but does your cat understand Quantum Mechanics?

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I think not - well, not exactly. It is the act of opening the box and observing the contents which collapse the associated waveforms. I'm with ed84c on this, however, the cat can collapse its own waveform through self observation. I've discussed this with my own cat and she assures me she would notice if she were dead!

The cat can do what it likes, the superposition still exists from our point of view.

Remember, folks, that observing is any method of discovering whether the cat is living or dead. Find the center of mass of the box, shake it a bit, call in a psychic. These all count as 'observing' just as much as opening the box.

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The cat can do what it likes' date=' the superposition still exists from our point of view.

[/quote']

So superposition exists from our point of view? Would you say that this means that it is not a property of quantum particles and they can do what they like?

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The cat can do what it likes' date=' the superposition still exists from our point of view.

Remember, folks, that observing is [i']any[/i] method of discovering whether the cat is living or dead. Find the center of mass of the box, shake it a bit, call in a psychic. These all count as 'observing' just as much as opening the box.

Smelling decayin cat...

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As I understand the story, Schroedinger made up this thought experiment to demonstrate to his peers just how ridiculous QM is. Schoedinger was more of a wave man and he disliked his equation being hijacked by the QM sect. He found QM unsettling and didn't like it at all.

Indeed he said: I don't like it (Quantum Mech.), and I'm sorry I had anything to do with it.

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Ahh...but does your cat understand Quantum Mechanics?
I'm uncertain.
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So does the cat cease to be in a superposition of states after, say, a fortnight? You can thus just wait out quantum mechanics and beat Schrödinger with your box, which contains a dehydrated, starved and quite possibly somewhat mummified cat!

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So does the cat cease to be in a superposition of states after, say, a fortnight? You can thus just wait out quantum mechanics and beat Schrödinger with your box, which contains a dehydrated, starved and quite possibly somewhat mummified cat!

Unless, by some quark of quantum physics, your cat quantum-tunneled right out of the box, but you wouldn't know that until you opened or even lifted the box.

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What if you had two cats in the box, one male and one female. After, say, 10 minutes a decay device will trigger one of them dead in a way that won't effect the other. (Say it triggers a cyanide capsule to rupture in the stomach).

So you have a live/dead cat and another live/dead cat. Can they interfere with each other?

Assume there is enough food and water in the box/system and half the box was isolated/compartmented so the cats can't get to it because of a trap door than wasn't (quite) big enough.

After a year the trap door is sealed and the isolation/compartment is saved and the remaining half is jettisoned into a black hole.

When the isolation/compartment is opened could it contain any kittens?

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Indeed he said: I don't like it (Quantum Mech.), and I'm sorry I had anything to do with it.

I thought Einstein said that?

Edit - nm, I looked it up your right.

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I think we left out a state...

"In fact, the mere act of opening the box will determine the state of the cat, although in this case there were three determinate states the cat could be in: these being Alive, Dead, and Bloody Furious."

-- Schrodinger's Moggy explained (Terry Pratchett, Lords and Ladies)

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In the quantum mechanical model nothing ever happens! The particle never has to decay. The probability just keeps getting closer and closer to one. There is nothing to force a real event to happen. This is very confusing because what we observe is always real events. We see the particle decay at some particular time.

Maybe maths breaks down here as a model of the world. If one is two and somewhere else at the same time... maybe people have to chuck it. Maybe they already did?

Maybe real probabilities are like springs under pressure, at 0.999999999999999999999999999999999999999999999999999 probability

it just happens ... cause it's a real event, not a mathematical construct.

Whatever, I don't like cats anyway...

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Schroedinger's bit is just a representation, it's debatable whether or not the cat s a qualified observer, which is what the theory requires; assuming, for the moment, the cat isn't a qo, then either you 'smell decaying cat, or you don't. Either one determines whether or not the cat is dead or alive; until you observe, the cat is neither and both.

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• 3 weeks later...

A slight doubt here. Schrodinger's cat would be alive or dead but if you believe in half dead half alive thingi then that leads to multiverse theory right?

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