Schrodinger's Cat

[catanon]

I was reminded of this strange little thought experiment whilst reading Hellsing, and obtaining Oberstammfuhrer Schrodinger as my new favorite character ever.

Anyway, from what I understand, the whole experiment is based upon quantum mechanics (which confuses me to no end) and is meant to be a slight mindfuck for those who understand it...I think.

Here's the original thing from Schrodinger

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 that 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.

It is typical of these cases that an indeterminacy originally restricted to the atomic domain becomes transformed into macroscopic indeterminacy, which can then be resolved by direct observation. That prevents us from so naively accepting as valid a "blurred model" for representing reality. In itself, it would not embody anything unclear or contradictory. There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.

Now, I still have no idea how the theoretical idea of an equally alive and dead cat was supposed to occur. I can only think of a cat that is either dead or alive due to the possible decaying of the radioactive substance.

So tell me, do I get it in the slightest or am I just too stupid to understand at all?

Thanks in advance.

[SimSim]

Yeah, I don't get it from that description either. Someone once did explain it to me in a way where it made sense that the cat was both alive and dead, but I can't remember the explination sadly.

[catanon]

Dang, if I ever find a good way of explaining it, I could totally mindfuck with my friends.

[Thejebusfire]

I think the cat is supposed to be alive and dead at the same time.

And Schrodinger is the cutest nazi ever.

[lumberjackninja]

Ahem.

**puts on physics hat**

This is a very commonly used scenario to illustrate both the nature of quantum mechanics, and the relationship between statistics and the individual data points.

Some background:

Radioactive stuff decays. In fact, it decays exponentially, and these rates are very well known. It takes a certain amount of time for a given radioisotope sample to decay to half its original count, and the same time to decay to half yet again (i.e., a quarter of the original sample).

while we can predict the decay of a given radioisotope with extreme accuracy, we cannot say the same thing about the individual atoms. You know that half the atoms will decay; you don't know which ones, though.

This is all fine and good until you get to situations where you're watching a single atom. Will it decay? Will it not? Who knows! It's somewhat of a game, if you think about it. Rolling a two-sided die, as it were.

The point with Mr. Schrodinger's feline is that at this point, you simply cannot know without looking. There is no predictive power. This is due to the nature of how we observe things- namely, by bouncing photons off of them (yes, physics afficiondos, I am counting only the EM interaction and not the weak or the strong).

You have to read closely the description of the setup: notice how the cat is in a steel tank. Take this to mean that kitty is causally isolated from the rest of the universe: whatever happens in the tank, the rest of the world continues chugging along just like it had (see also: the "God Can't Be Proven Means God Doesn't Exist Thread"). While normally these weird quantum indeterminacies, as Schrodinger calls them, are restricted to things of similar size t atoms and smaller, once you add the Geiger-Muller tube and a device that acts upon whether it goes off, you magnify those effects to the macroscopic world.

Ultimately, the point is two fold: firstly, in a system like this, you cannot know what state the cat is in until you look at it directly; it has to be one of the two, but there is no way of determining which before hand, except to say that as time goes on, the likelihood of finding a chemically terminated feline increases. Secondly, and perhaps more importantly, is that the state of the cat does not matter until you look. Any predictions you make about anything else in the universe at that point in time will be the same whether or not the cat is alive or dead; you could also just assume that the cat doesn't exist.

The only time it matters, and is observable, is when you open the steel chamber and find either an angry kitty or a dead cat.

It is ridiculous on its surface, but only until you realize that you say the cat is both alive and dead because you are forced to make a statement about its current status.

[Vypernight]

I support this experiment (with multiple trials to make sure) 100%.

[starbrewer]

Schrödinger gets busted by the ASPCA!

[catanon]

Jul 23, 2009 1:35:21 GMT -5 Thejebusfire said:

And Schrodinger is the cutest nazi ever.

If there was ever any Nazi that I wouldn't want off the face of the Earth, it's Schrodinger. If only to be able to go "Who's the cutest Nazi?! You are!"

[Thejebusfire]

lumberjackninja- Makes me wish I would paid more attention in science class.

[Shano]

So for the most part what lumberjackninja said is correct. There are a few comments I want to make.
His explanation relies on adopting particular interpretation of quantum mechanics. It is called the Copenhagen convention. While it is the accepted interpretation among physicist, it is not the only one possible.
It is also the case that I do not support the phrase "the cat is both dead and alive". What I prefer to say is that the cat is in the state of being able, upon observation, to fall into the state of "dead" or "alive". So it is neither dead or alive. As the cat is isolated the question of is it objectively dead or alive before making an observation is moot. There can not be an objective answer. Aside from an metaphysical absolute (say god) there is no entity that could know objectively without observation. And even one observation will set the result.
In that sense after someone checks if the cat is dead or alive but doesn't tell you the answer you don't get to set the result again. Moreover in an idealized situation you don't need to be told. The universe already knows the answer and you could in principle make a measurement of the universe itself to get the information about that cat (visualize this as if you had a mindreading device to scan the observer that refuses to tell you the result).

[Angel Kaida]

Jul 23, 2009 15:51:41 GMT -5 @catanon said:

Jul 23, 2009 1:35:21 GMT -5 Thejebusfire said:

And Schrodinger is the cutest nazi ever.

If there was ever any Nazi that I wouldn't want off the face of the Earth, it's Schrodinger. If only to be able to go "Who's the cutest Nazi?! You are!"

Why does everyone insufficiently love Rip Van Winkle?! Sure, Schrodinger's adorable and has little kitty ears, but... Rip Van Winkle is such a glorious and wonderful badass!

[tygerarmy]

[catanon]

Jul 23, 2009 19:39:24 GMT -5 Angel Kaida said:

Jul 23, 2009 15:51:41 GMT -5 @catanon said:

If there was ever any Nazi that I wouldn't want off the face of the Earth, it's Schrodinger. If only to be able to go "Who's the cutest Nazi?! You are!"

Why does everyone insufficiently love Rip Van Winkle?! Sure, Schrodinger's adorable and has little kitty ears, but... Rip Van Winkle is such a glorious and wonderful badass!

Hey, I loved Rip as much as anyone else. It sucks that he died so suddenly whilst everyone (not counting Schrodinger) got a really cool fight and death scene.

[catanon]

Jul 23, 2009 20:54:22 GMT -5 tygerarmy said:

Yes. YES. YES!!!

You, sir, have won yourself one free internet.

[DarkfireTaimatsu]

That prompts me to paste this a second time, since it hasn't been noticed in the Nerd Porn thread: