What is "Schrodingers cat"?

A hypothetical critter, used in a thought experiment to demonstrate the 'spooky' nature of quantum physics.

Schrodinger was actually criticising the Copenhagen interpretation of QP; he tried to point out how ridiculous it was to extrapolate quantum phenomenon to the macroscopic state. Here's what he actually said;

One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small, that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts.

What he meant was, according to QP, until you open the box, the cat is both alive and dead at the same time! You only fix it in one state by observing it!

He seemed to hope that everyone would agree that this was daft, in fact, Quantum physicists said 'Yes, that's exactly how it is', and Schrodinger's cat has become a classic illustration of QP!

Oh- oh- oh - this was on Stargate the other day. You have to put a cat in a box with something which has a decay rate - is it a radioactive isotope? (anyway to continue) - and at any given time Schrodinger hypothesised the cat could be both dead and alive! Quantum Physics! I have absolutely no idea about this field but, I am aware of the theory that ther are an infinite number of parallel universes, (multi-verse), and if in each one you make a different decision you will cause another multiverse to appear, hence Schrodinger's Cat theory! lol-D

in a nut shell

he was a cat that was owned by Schrodinger

put in a box

and poison was fed into the box

the idea of the experiment was to find out if Schrodinger and co thought that the cat was alive or dead the could think it was dead and it could be alive or the opposite

the idea is that they don't know

My understanding is that there is a hypothetical experiment where a cat is in a box with a radioactive source that may or may not kill the cat. The box is sealed and if the seal is broken, then the cat dies anyway so there is no way of knowing whether the cat died from the radioactive source or by opening the box. I think you have to ignore any redress to pathology. Essentially it's a metaphor for an experiment that cannot be interpreted by the available analytical techniques.

Schrödinger's cat is a seemingly paradoxical thought experiment devised by Erwin Schrödinger that attempts to illustrate the incompleteness of the Copenhagen interpretation when going from subatomic to macroscopic systems. Schrödinger proposed his "cat", after a suggestion of Albert Einstein's, stating that if a scenario existed where a cat could be so isolated from external interference (decoherence), the state of the cat can only be known as a superposition (combination) of possible rest states (eigenstates), because finding out (measuring the state) cannot be done without the observer interfering with the experiment — the measurement system (the observer) is entangled with the experiment.

The thought experiment serves to illustrate the strangeness of quantum mechanics and the mathematics necessary to describe quantum states. The idea of a particle existing in a superposition of possible states, while a fact of quantum mechanics, is a concept that does not easily scale to large systems (like cats), which are not indeterminably probabilistic in nature. Philosophically, these positions which emphasize either probability or determined outcomes are called (respectively) positivism and determinism.

I remember a friend explaining this to me in a physics lesson once. Basically the idea is there to illustrate quantum thory. And it goes thus: a cat is in a sealed metal box with a small ammount of radioactive material which every time it decays sets of a hammer to break a vial of substance that will kill the cat and has a 50\50 chance of living\dying. Without opening the box we cannot know if the radioactive material has decayed and the vial broken and therefore if the cat is dead. But if we open the box we are changing the experiment and that could change the outcome, therefore there is no way to know the outcome, therefore the cat must be both alive and dead this is sometimes called the observer's paradox. Where no one outcome occurs unless someone is there to observe it.

A cat is placed in a box, together with a radioactive atom. If the atom decays, and the geiger-counter detects an alpha particle, the hammer hits a flask of prussic acid (HCN), killing the cat. The paradox lies in the clever coupling of quantum and classical domains. Before the observer opens the box, the cat's fate is tied to the wave function of the atom, which is itself in a superposition of decayed and undecayed states. Thus, said Schroedinger, the cat must itself be in a superposition of dead and alive states before the observer opens the box, ``observes'' the cat, and ``collapses'' it's wave function.

A moggie owned by a grimalkin called Mrs Schrodinger

Its tough to explain, but ill have a go. Put something you know will kill the cat in the box with the cat and close the lid. Keeping cat and killer seperate. You wont know if its alive or dead untill you open the box. At that point however, you have interfered with the experiment. Its all just bulls**t theoretics really. They say that untill you open the box, the cat exists in both states, alive and dead. Just looking can determine the state. dont think its anything to do with universes though. It is just a theoretical experiment trying to detail the ambiguity of quantum theory.

a) It was hypothetical 'cat' - in a thought experimant

it was not a real 'norwegian forest cat' (is there such a thing?)

b) the trigger proposed for this thought experiment was the decay of a radioactive substance.. there was no bullet, no light pulse.

the 'cat', thought experiment has been told and retold

in classrooms and lecture halls. Like chinese whispers,

the details get changed depending on the narrator and the audience.

It would be a pointless exercise to try to do this experiment, in real life, because as soon as you observe the cat, you collapse the wave function and force an outcome.