I never did understand what Schrodinger was trying to say.

In what senses can it be "both"? Surely it has to be "either"?

http://en.wikipedia.org/wiki/Schrödinger%27s_cat

Hmm the link won't work for some reason

Or maybe it will and won't

That's the whole point of it - to illustrate the fact that quantum physics is based upon probabilities, not certainties. Because of the way things work at that level, you never actually know anything with certainty, you just know the probability of something. In the same way, before the box is opened, there is a 50% probability that the cat is dead and a 50% probability that it is alive. Therefore, using the language quantum mechanics uses to describe things, a physicist would say it was both alive and dead at the same time.

It's also a way of showing that you can't apply the principles of quantum mechanics to 'real world' objects, that the rules don't cross the barrier where QM meets newtonian physics. OK, there are now examples where we can see this does happen but at the time they were thought to be mutually exclusive. He was, to some extent, taking the mickey.

Jon

Perhaps it's just semantics, but it's easier for me to think of it as neither alive nor dead rather than both alive and dead. That could be a complete misunderstanding of it though!

It's neither dead nor alive. In the same way (I think) that light is neither a wave nor a particle but we can use wave-particle duality to explain its behaviour.

IIRC, the cat can be thought of both dead and alive, but it's only when you observe the cat that everything collapses into one waveform.

You are right in that you are wrong

Schrodinger's cat is not about a cat. OK, well it is but not really.

It's a thought experiment about quantum mechanics.

In quantum mechanics particles can exist in multiple states at the same time. Say a particle has a state called "Spin" and Spin can be either clockwise or anti-clockwise. In quantum mechanics the particle can (and almost certainly will) have both clockwise and anti-clockwise spin simultaneously. It is only when the particle is observed (i.e. put under pressure to choose one or the other) that it finally falls into one state.

It is similar to electrons following a path. An electron can (and will) follow EVERY possible path between is current location and it's destination (say an electron emitter and a electron detector). It is only when one particular path is observed that you pin the electron down and make it explicitly choose that path.

Now, Schrodinger's cat is a thought experiment taking quantum mechanics into the macro world.

You put a cat inside a sealed box with a vial of something poisonous, a hammer to break the vial and a trigger to set off the hammer. Now the trigger is activated by a quantum mechanism (say a particle being emitted from a radioactive source with a known half life).

Of course, you could put the cat in a glass box and watch what happens. At some point in time the radioactive source will emit a particle and trigger the hammer to smash the vial and kill the cat. But only when you observe it doing so.

Inside a sealed box you know that the amount of time has passed sufficiently that the radioactive source is highly probable to have emitted its radiation but that is only a probability on a quantum mechanism. So, the radiation is in a state of both being emitted and not being emitted. It only decides which way to fall when it is observed. Following from that the cat is in a state of both being alive and being dead. It only decided which state it is in when the box is opened and the conditions observed.

... or something

I had a feeling i'd missed the crux of it!

Don't worry, took me a long time to work out how it worked and what it meant.

I think I read a book entitled In Search of Schrodinger's Cat or something. Apparently, there was a sequel about kittens (according to my physics teacher).

My understanding of this is that an electron can be moving and have a position. However, when you observe it, you can only tell one of these states. All amounts to similar things. You can know state a but not state b, or vice versa.
http://en.wikipedia.org/wiki/Heisenberg ... _principle

Interestingly, this makes transporters, such as those seen on popular TV Sci-Fi show Star Trek somewhat impossible as you would need both states to correctly deconstruct and reconstruct the object being transported. Thankfully, the boffins at Star Fleet who built the transporters included the Heisenberg Compensator to salve this problem.
http://en.wikipedia.org/wiki/Heisenberg ... imitations

Thus a worthy and thought provoking thread has been successfully steered around into the mire that is popular culture.

That's true for the Heisenburg uncertainty principle but not quite the same as quantum superposition (which is where Schrodinger's Cat is based).

http://en.wikipedia.org/wiki/Quantum_superposition

Wener Heisenberg is stopped by the Police in his car.
Policeman walks up to his window and says "Excuse me sir, do you know how fast you were going?"
Werner replies "No, but I know exactly where I am"

That joke just makes me think of Breaking Bad and how much I'm now looking forward to Season 4

I've got those books. Read them on holiday once (yes, I don't really do 'light reading'). One of the better pieces of 'pop science' literature.

Now that is about the only thing that makes senses to me on this page.

Electrons taking every path, spin being both anti and clock. Nope that does not make any sense to me. Maybe it never will.

This is far too Big Bang Theory for me