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Anyone hear of "Schroedinger's Cat"? (1 Viewer)

Kevin P

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I think, distilled down, I just don't understand how the Geiger counter doesn't count as observing and thereby robbing the quantum particle's flexibility to be several things at once. Anyone able to help?
Or the cat itself would be observing, at least it would know if it was alive or dead.
 

Lew Crippen

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I think, distilled down, I just don't understand how the Geiger counter doesn't count as observing and thereby robbing the quantum particle's flexibility to be several things at once. Anyone able to help?
It’s not meant to be a perfect analogy, but rather the presentation of something more easily understood than particle decay: that is, whether a common household pet is alive or dead. And the fact that we cannot know with certainty the state of being until we make an observation, and when we have made the observation, we have altered the state of the universe (the box), thereby setting up new conditions.

IIRC, all of the apparatus in the box, was only to represent for laypersons such as me, a method by which we could believe that the cat was alive or dead due to an instance of particle decay.

It’s the concept that we are supposed to get, not necessarily the particulars.

I think this is right with 75% certainty

Or not.

But wait the time and observation has changed—there is now only a 67% chance that the above is true.
 

Joseph DeMartino

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Right, the "cat" thing was all about probability and being able to express an unknowable in a single equation. The only reason the decaying particle is in their is to ensure an event that is in and of itself predictable within given parameters, and which is not subject o interference.

Regards,

Joe
 

Mary M S

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Seems like I've seen a mention of "Schroedinger's Cat" in connection with the research into Quantum Computers.

Reflecting the quandary that occurs within a Quantum Computer theoretically and in the first prototypes built that when you disturb the processes it affects them. They have to be completely protected from outside influences. By looking to see "where" it is, - like the cat (alive or dead) you potentially rearrange the ultimate outcome.
 

StephenK

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I think what's important to stress about S's Cat is what Joe DeMartino said in his first mail. It's not that the cat is either alive or dead and you just don't know, but that the cat is alive and dead with decreasing amounts of "alive" as time progresses.
Using Joe Szott's timetable, in hour 2, the cat is in an undeterminate state of both 25% alive and 75% dead. The act of opening the box doesn't merely reveal which state he's in, it actually forces the cat to "pick" a state. The measurement, in this case looking at the cat, reduces the uncertainty to zero and makes the cat at that point either dead or alive. I know it seems like nit-picking but it's a crucial difference in view.
 

Holadem

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Stephen, isn't the difference in the way we look at things, rather than what is?
Could it be that in reality, the cat is eitheralive or dead, but combining both states into a single variable makes things mathematically easier?
To draw a parallel, imaginary numbers are an absolutely essential mathematical tool... but they are just that, a mathematical tool.
--
Holadem
 

StephenK

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Holadem,
Could it be that in reality, the cat is either alive or dead, but combining both states into a single variable makes things mathematically easier?
I wish I had the brains/background to better understand/explain this, but I don't. The cat really is dead and alive. It goes to the heart of quantum uncertainty. The cleverness of the Schroedinger Cat thought experiment was that it converted a purely quantum (extremel small scale) property, uncertainty, into a classical (large scale) property, e.g. is a cat dead or alive. Forgetting the cat for a minute, just go back to the particle itself, has it decayed or not. The same question applies here, has the particle decayed or not, and does measurement merely reveal what already exists but is unknown. The same answer applies, knowing creates the reality.
Take a look at Philip's link, it gives a really spooky real world experiment that build's on Young's 2 Slit experiment. Merely creating a situation where information is available, but not used, knowing which of 2 paths a photon takes through a barrier, eliminates quantum uncertainty and removes the interference pattern that results from a photon's particle/wave duality. In effect, just giving you the ability to measure something, forces the photons to behave as simple point particles. Remove that ability and they behave again as waves.
Having only a layman's knowledge, it's something I just accept. Much better minds than mine don't understand it, so I don't feel bad :)
 

Joseph DeMartino

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Yes, the ultimate fallacy of the cat experiment is the underlying assumption that a Human action of any kind can force a cat to do anything. This would make a lot more sense if it were a dog. :)
Regards,
Joe
 

Mark R O

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Dammit! I thought I had the point if not the details.
StephenK's comment that our observing the cat makes it choose a state of dead or alive made sense. But most of the replies are based on a single inviolate fumdamental. That is the assumption that when the cat is in the box, it exists at all, or we to it. We have zero to establish this, our links to the box space are limited to interaction with the atomic decay. And that link need not be bi-directional. Was the riddle an exercise in "odds making" for event causations or to discuss alternate realities and their enabling effects on one another? Considering killing the cat myself.
 

Alex Spindler

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:laugh:
I guess my hangup is how the quantum particles could influence atomic/molecular structures.
You could do some interesting things with this I suppose. If you had a coin machine with two ramps, and a switch that selected which ramp the coins would follow that was influenced by a decaying particle, you could double your money every time you dropped a coin.
Of course, as soon as you opened the box to get you money you would be back where you started. But, you would be rich until you cashed in.
I remember one feeling I had when being taught this subject. I always felt like PT Barnum had tried his hand at physics. "In the box is a cat who is both alive and dead. 5 cents to see. *lifts box* Well, you caused the cat to die. Thanks for visiting Quantum Mechanics."
 

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