Schrodingers Cat

[paigetheoracle]

Personally speaking as a non-scientist, I think Schrodingers theory is more full of holes than his cat box! The cat, alive or dead, is potential not actual to the external observer - only the cat truly knows if it is alive or dead (This is the witness problem as far as I can see in every situation - you cannot 'know' what somebody else experienced, only speculate - doubt must always exist, probably even with the witness themselves: What was sensed cannot be disputed but was it subjective or objective? But I digress).

 

If the box was air tight, logically the cat is dead from oxygen starvation or soon would be. If it had air holes, you would hear it and could use a torch to detect motion. Also you could put the box on scales or some other measuring device to detect motion. You could also use a clear plastic box instead of an opaque one. You could also put a microphone in the box or a camera and light source. In theory, 'the theory' is fine but real life discloses it just as an intellectual game of no real consequence.

 

This is like Bishop Berkeley's speculation about the quad. Is it there when he isn't there to witness it? Of course it is because he didn't construct it with his mind, it has independent existence outside of his reality. It has been built by human hands but the original material was not created by people, just fashioned by them. Man can destroy the created world but is only now on the borders or creating something from nothing or matter from energy. Even genetics only manipulates created material, not makes it from scratch.

 

Einstein or whoever it was said that we are like children playing on the shores of eternity, was right.;)

 

Moderators, if you think this may be more suitably located in the philosophy or philosophy of science section, please move it without further ado - after all I'm no physicist and can't 'physically' move it myself (Well I could cut and paste it but that's beside the point:lol:).

[Tormod]

The entire point of the cat in the box thought experiment is the decay of a single atom, which would cause the release of gas and kill the cat. Since there is no way to predict exactly when an atom decays, there is no way to know if the cat is dead or alive until we check. Bypassing it with other measuring equipment ruins the experiment, since in effect the experiment transfers the superposition state of the single atom to cover the entire box (and thus the cat).

 

I don't think it was ever meant to be done in practice.

 

Or as Neil Gaiman has a character observe in American Gods, "if they don't ever open the box to feed it'll eventually just be two different kinds of dead." ;)

[CraigD]

If the box was air tight, logically the cat is dead from oxygen starvation or soon would be. If it had air holes, you would hear it and could use a torch to detect motion. Also you could put the box on scales or some other measuring device to detect motion. You could also use a clear plastic box instead of an opaque one. You could also put a microphone in the box or a camera and light source. In theory, 'the theory' is fine but real life discloses it just as an intellectual game of no real consequence.

The thought experiment explicitly specifies that you must use a box that prevents any detection of the status of the cat. If you don’t follow its directions, via any of the means you describe, you aren’t performing the experiment as specified.

Personally speaking as a non-scientist, I think Schrodingers theory is more full of holes than his cat box!

It’s important to understand that "Schrödinger's cat" isn’t a scientific theory – something meant to explain anything – but rather a “though experiment” – something meant to make people think about a specific interpretation of a scientific theory, in this case the Copenhagen interpretation of quantum mechanics.

 

We have from various published papers and private letters between Schrödinger and others that Schrödinger didn’t believe a macroscopic ensemble of a huge number of particles, such as a cat, could possibly exists as a half alive/half dead superposition. He described his famous thought experiment as a “quite ridiculous case”. What he seems to have meant to say to his fellow physicists is something like “take a moment and look at what strange things the mathematical formalism we’re coming to accept must lead of to believe! Perhaps we’re overlooking something very important.” Note in the quotes from the wikipedia article linked above Einstein writing to Schrödinger “You are the only contemporary physicist, besides Laue, who sees that one cannot get around the assumption of reality – if only one is honest.” From this and other remarks, it’s apparent that Schrödinger, Einstein, and a minority of like-thinking physicists worried deeply that the majority of their fellow physicists were not be honest with themselves in not thinking about the consequences of their math, simply accepting that it succeeded in correctly predicting the outcome of the experiments they could do, which things included electrons in bubble chambers, but not cats in boxes.

 

It’s important to grasp what strange times the 1930s and on were for physicists like Schrödinger. Seeming ridiculous theories not only worked, but were the only ones that worked. Reactions to reminders of what strange assumptions they were being forced to accept such as Schrödinger’s were varied: some, like Einstein, agreed that they must be overlooking something important. Others just accepted that they must live with weird paradoxes like these, perhaps until they had the ability to scale up experiments from single electrons to whole cats in boxes (which we’re still far from being able to do). Still others came up with explanations that were, for lack of a better term, more or less mystical.

 

Eugene Wigner took Schrödinger’s cat paradox and added to it. In “Wigner’s friend”, you don’t check on the cat yourself, but have a friend do it, then tell you what he finds. According to the thought experiment, until you’ve spoken to your friend – maybe days or years later – both the cat and the friend exist in a supersition of “live cat+friend who found a live cat” / “dead cat+friend who found a dead cat” (usually called “live cat/happy friend”, “dead cat/sad friend” for short). Wigner concluded that, while Schrödinger’s idea of a half live/half dead cat was sensible, a half knowing the cat was live/half knowing if was dead person was not, so something about a person being involved had to be important, a form of “quantum mysticism” known now as “Consciousness causes collapse”. Others came up with ideas even weirder.

 

Paige, you seem to have come up with a variation of Wigner’s idea, in which the cat is assumed to have whatever consciousness it takes to collapse its superposition of alive/dead states into either alive or dead.

 

:) My take on the question, for what it’s worth, is that quantum superpositions of states collapse when the interact with systems much smaller and simpler than cats or physicists’ friends. I suspect that a few atoms are enough that, if a system interacts with them, that system will collapse to a single state.

 

If I’m right, a practical consequence will be that ”quantum computers” that can perform calculations such as factoring numbers are impossible, and when eventually built, won’t work. Since a lot of work is currently in progress on making quantum computers, if I’m wrong, I should know it in within the next couple of decades.

[belovelife]

so, with the cat in the box, it will eventually die, so there is 100% chance that

the eventual outcome is the cats death right. now the question is, is it dead already.

with the cat in the box, you cannot get an accurate measurement of the time of

death, only the cetainty of weather it is alive or dead. so the idea of the cat being in the box itself, hinders scientific analysis, because of the details involved with the cats death cannot be measured accuratly. thus, having the cat in the box in the prescribed state, would hinder any sort of scientific measurement.

 

right?

[CraigD]

so, with the cat in the box, it will eventually die, so there is 100% chance that the eventual outcome is the cats death right. now the question is, is it dead already. with the cat in the box, you cannot get an accurate measurement of the time of death, only the cetainty of weather it is alive or dead. so the idea of the cat being in the box itself, hinders scientific analysis, because of the details involved with the cats death cannot be measured accuratly. thus, having the cat in the box in the prescribed state, would hinder any sort of scientific measurement.

 

right?

No.

 

It’s important to understand the exact essentials of the Schrödinger's cat thought experiment. At its heart is a process that is unquestionably quantum mechanical in nature. Usually, this is described as the decay of a precise quantity of some radioactive element such that there is exactly a 50% chance of the nucleus of 1 or more atoms of it undergoing spontaneous fission (which is also known as decaying) within a precise interval of time, usually described as 1 hour. The cat is assumed to be healthy, the box to contain enough air, that its chance of survival if the box contained no deadly device would be practically 100%. A detector that is practically 100% reliable at detecting a decay event (such devices have long been commonplace) is connected to a mechanism that releases a poison that is practically 100% able to quickly kill the cat. In most illustrations, this is depicted as a rather cartoonish hammer hanging over over a glass bottle, connected to a nondescript box. After the hour has passed, the device is automatically disabled, and a person opens the box, and sees if the cat is alive or dead. He doesn’t care about the details – how or when the cat died, or what it’s doing if alive – only if it is alive or dead.

 

As a physics experiment, there’s no need to have the poison and the cat – the results would be exactly the same 50% observed rate if, instead of the poison release mechanism, the radioactive substance and detector assembly had a simple yes/no display flag.

 

Everyone with a decent understanding of physics accepts the idea that things like a single radioactive element nucleus can exist in a state of both decayed and not-decayed (a “superposition of states”). If you don’t accept this and similar consequences of quantum physics, you simply can’t explain why the universe works the way it appears to work. The point of Schrödinger's and Wigner’s thought experiments are that when extending to much bigger things, like cats and people, it’s harder to accept the idea of superpositions of states. In situations like this, however, the basics of quantum physics don’t draw a clear line between where their concepts make sense, and where they don’t.

 

IMHO, this hints at the need for a more fundamental theory, in which the formalism (the exact rules) of quantum physics arise as a special case. Such theories exist, but are difficult and speculative – a good thing for present and future physicists, who wouldn’t want science to get easy or dogmatic. :)

[paigetheoracle]

The entire point of the cat in the box thought experiment is the decay of a single atom, which would cause the release of gas and kill the cat. Since there is no way to predict exactly when an atom decays, there is no way to know if the cat is dead or alive until we check. Bypassing it with other measuring equipment ruins the experiment, since in effect the experiment transfers the superposition state of the single atom to cover the entire box (and thus the cat).

 

I don't think it was ever meant to be done in practice.

 

Or as Neil Gaiman has a character observe in American Gods, "if they don't ever open the box to feed it'll eventually just be two different kinds of dead." :)

 

I stand dissected, corrected, rejected and dejected but in the words of Michael Jackson

"I could have started something, yeh, yeh":eek2:;)

[maddog]

The entire point of the cat in the box thought experiment is the decay of a single atom, which would cause the release of gas and kill the cat. Since there is no way to predict exactly when an atom decays, there is no way to know if the cat is dead or alive until we check. Bypassing it with other measuring equipment ruins the experiment, since in effect the experiment transfers the superposition state of the single atom to cover the entire box (and thus the cat).

 

I don't think it was ever meant to be done in practice.

 

Or as Neil Gaiman has a character observe in American Gods, "if they don't ever open the box to feed it'll eventually just be two different kinds of dead." :xparty:

In the spirit of supporting PETA, I read a book by Roger Penrose, Roads to Reality, wherein

he modifies the experiment so as not be construed as "killing cats". I suspect other

authors will in the future put in disclaimers such as "No feline or animal lifeforms of any

kind were actually harmed in these experiments. They are thought experiments only".

 

;)

 

maddog

[paigetheoracle]

In the spirit of supporting PETA, I read a book by Roger Penrose, Roads to Reality, wherein

he modifies the experiment so as not be construed as "killing cats". I suspect other

authors will in the future put in disclaimers such as "No feline or animal lifeforms of any

kind were actually harmed in these experiments. They are thought experiments only".

 

:)

 

maddog

 

This sounds like political correctness to cover up animal cruelty - just wait till I get my hands on that Schrodinger!