[MarkS]

You used to have this little animated pic in your sig. It started looking like a calico cat, but then it sort of melted away. At the end it looked like someone shot it full of holes and then dumped acid on it.

I have always wondered what that was? What was it?



Mark

[wgscott]

To illustrate the absurdity of the Copenhagen interpretation of quantum mechanics, Schodinger (the real one) developed "Schrodinger's cat." The cat would be put in a box with some sort of radio-isotope and a radiation-detector. If the isotope emitted radiation, a probabalistic event whose probability amplitude one calculates from the Schrodinger equation, and the detector detected it, it would send a signal to a tiny explosive that would discharge and break an ampule of cyanide gas that would then be released, killing the cat. The Copenhagen interpretation of quantum mechanics held that a system exists only as a superposition of two or more probabalistic states until someone makes an observation and collapses a wavepacket. Therefore the cat must exist in a superposition of the dead cat state and live cat state until someone comes along and collapses the wavepacket by opening the box and making an observation.

Schrodinger by the way favored a more objective, statistical interpretation of quantum mechanics, as did Einstein and de Broglie. Bohr and Heisenberg favored what came to be known as the canonical or Copenhagen interpretation, which has this subjectivist observer interfering with the experiment phenomenon that Schrodinger was trying to argue agains using the above reductio ad absurdum argument.

HTH

[wgscott]

Oh, wait ... you didn't ask me, did you? Sorry. Schro. will tell you that is was an animated gif.

[MarkS]

So basically what you are saying is that the cat was both dead and alive until someone opened the box and observered the dead cat.

But what happens when you close the box and do not record your observation? Is the cat still dead? Was the cat really ever alive?

Is the mere act of observation enough to cause the cat to change quantum states or does the observation need to be recorded?

In all reality, this is the same as the question: "If a tree falls in the forrest and no one is around, does it make a sound?".

Assuming that Copenhagen was correct, there would be no sound unless you were in the forrest. However, this would in fact be incorrect because there are thousands of hearing animals in the forrest that could hear the tree.

So using that hypothesis, couldn't the live cat (assuming that it was ever really alive) have observed itself in the box and caused it's own change in quantum states? Do you really need an outside observer to cause this change?

Mark

[ronjon]

let me run over the box with my car. that should take care of the cat...that is, unless u r really not sure a 57 caddy wouldn't do the job.

hth,
rj

[Ninong]

Originally posted by MarkS

But what happens when you close the box and do not record your observation? Is the cat still dead? Was the cat really ever alive?

Recording, or not recording, your observation makes no difference. The cat was both dead and alive at the same time. Maybe we should say that the cat had the potential to be dead or alive.

Is the mere act of observation enough to cause the cat to change quantum states or does the observation need to be recorded?

Observation causes the wave to collapse and revert to normal particle state... no more superposition... no more possibility of being in two places at the same time. I wish Schroedinger had not used a cat in his explanation, a single atom would have sufficed.

In all reality, this is the same as the question: "If a tree falls in the forrest and no one is around, does it make a sound?"

No.

Assuming that Copenhagen was correct, there would be no sound unless you were in the forrest. However, this would in fact be incorrect because there are thousands of hearing animals in the forrest that could hear the tree.

Which is why this analogy doesn't work.

So using that hypothesis, couldn't the live cat (assuming that it was ever really alive) have observed itself in the box and caused it's own change in quantum states?

The so-called experiment has to be set up such that the cat cannot interfere.

Do you really need an outside observer to cause this change?

Observation fixes the reality of the state, or position, and therefore the possibility of two states or of being in two places at once no longer exists.

The trick is to be able to induce an atom to change states, or positions, back and forth on command. This would open up all sorts of possibilities. They don't know how to do this, but they're working on it.

Quantum mechanics provides a convenient explanation for the state of the universe prior to space/time... it does away with the nasty headache of infinity, which implies time, by allowing it to exist and not exist simultaneously.

Ninong

P.S. - WG, why can't you imagine the cyanide vial is capped with a single radioactive atom which may, or may not, decay in a given time frame and eliminate all the Rube Goldberg stuff?

[schrocat]

Damn wgscott...you covered that pretty well.
You sound just like a physics teacher!

Actually I've never heard of Erwin Schrodinger...until now.
He sounds like a real smart feller.
Except'n he aint never considered how hard it is to be putting a cat in a box.
Especially if they aint declawed.

I am a horrible speller and mistyped my desired board name of "Sprocket"....
I know...I know...what a dumb***.

I used the animated gif until someone on the board kept RAILING me about it.

Vicious and repeated attacks, the type that brings tears to one's eyes.

Here kitty kitty...

[Reinhold]

If it was fishkid's cat, it would be in the box out in the woods at the edge of town.

Have you ever tried to find a good quantum mechanic on a Sunday afternoon?

[schrocat]

Originally posted by Reinhold
If it was fishkid's cat, it would be in the box out in the woods at the edge of town.

[MarkS]

Originally posted by Ninong
Recording, or not recording, your observation makes no difference. The cat was both dead and alive at the same time. Maybe we should say that the cat had the potential to be dead or alive.

That's what I figured.

Observation causes the wave to collapse and revert to normal particle state... no more superposition... no more possibility of being in two places at the same time. I wish Schroedinger had not used a cat in his explanation, a single atom would have sufficed.

Yes, but why? How does me looking at the cat make any difference?
How about me thinking about the cat? Wouldn't that also be an observation in a sense? A single atom would make this easier though. It eliminates self observation.

No.

OK.

Which is why this analogy doesn't work.

Yes, but the cat knows it is in a box. Through that alone you could call it an observation. Therefore the cat is observing itself in the box, although not visually.

The so-called experiment has to be set up such that the cat cannot interfere.

Impossible, unless you remove that cat's brain. Even in a cat's primitive state it would know where it was, in a sense. It is trapped and must get out.

Observation fixes the reality of the state, or position, and therefore the possibility of two states or of being in two places at once no longer exists.

Yes, in our minds. If this is true then we really can control matter with our minds and have been doing it since the dawn of time.

The trick is to be able to induce an atom to change states, or positions, back and forth on command. This would open up all sorts of possibilities. They don't know how to do this, but they're working on it.

An observation is a mental state and has no influence on the physical world. If they can get this to work, then we would be promoted to an almost God-like status. If merely seeing or thinking about something can cause it to happen, then I could literally create a 500 gallon reef tank, fully stocked just be thinking about all the various parts.

Quantum mechanics provides a convenient explanation for the state of the universe prior to space/time... it does away with the nasty headache of infinity, which implies time, by allowing it to exist and not exist simultaneously.

And it makes the universe much easier to understand, even on a subatomic scale. Something that cannot be done with regular physics.

Mark

[Ninong]

MarkS ~

Unfortunately, IMHO, the cat idea makes the explanation more difficult than the original concept. He is trying to explain something that takes place on too small a scale to actually be "observed" by transferring the concept to the macroscopic scale in the form of a cat. To make this work, the first thing you have to understand is that the cat has no effect on the outcome whatsoever. The cat does nothing, observes nothing, has no interaction whatsoever with the situation it is in; it is either dead, alive or dying at any given moment (ask Schroedinger to explain it).

Superposition is implied on a microscopic level by observation of its interference effects. It is an attempt to reconcile wave mechanics and particle mechanics. Laboratory experiments along these lines are conducted at temps of -459F (near absolute zero) and measurements of an atom in a state of being in two places at the same time are on the order of 1/100,000,000th of a second.

Ninong

[MarkS]

Thanks, that makes a whole lot more sence! Seriously!

Mark

[schrocat]

Originally posted by Ninong
Why I hate Schroedinger's stupid cat...

How wude...

[MEC]

Well I liked the cat gif. I wish I could find another train gif I like. There dont seem to be many arround........Mike

[wgscott]

Originally posted by Ninong
WG, why can't you imagine the cyanide vial is capped with a single radioactive atom which may, or may not, decay in a given time frame and eliminate all the Rube Goldberg stuff?

Well, if decay of a single radioactive atom could break open the cyanide vial, you could. The decay releases a single photon or maybe an electron, anyway the signal is very tiny and needs to be amplified, hence the Gieger counter. The click you hear in the speaker when it counts a photon is amplification of the signal. If instead this amplified signal somehow opens the bottle (it doesn't really matter how), then one single radioactive decay has let loose the cyanide gas, which is the important part. How you get there really isn't so important, and remember, these were arguments taking place in the 1930s and 1940s when single-photon cat extermination technology was still in its infancy.