BBC Radio 4 has an great, half-hour science broadcast up for the next few days... unless someone rips it for posterity.
[url]http://www.bbc.co.uk/programmes/b00wr9qb[/url]
Wouldn't say it's worth a whole thread, but thanks, anything with quantum physics in is worth a listen!
Is this the experiment where they put a cat in a box next to poison, and it may or may not die, but if it's dead it can be both alive and dead until you look inside of the box?
[editline] yay [/editline] 100 posts :toot:
[QUOTE=muffinmastah;27846577]Is this the experiment where they put a cat in a box next to poison, and it may or may not die, but if it's dead it can be both alive and dead until you look inside of the box?
[editline] yay [/editline] 100 posts :toot:[/QUOTE]
Cant we just say it has a 50% chance of being alive and a 50% dead. give or take accounting the exact chances that the cat will activate whatever will kill it.
[QUOTE=muffinmastah;27846577]Is this the experiment where they put a cat in a box next to poison, and it may or may not die, but if it's dead it can be both alive and dead until you look inside of the box?
[editline] yay [/editline] 100 posts :toot:[/QUOTE]
Not entirely. It is put into a box, yes, with a radioactive element (just one single atom) and a poison. When the atom decays, a mechanism releases the poison and the cat dies.
The thing now is, the time of decay is totally random. When the time corresponding to the half-life passed, the atom has a chance to be 50% decayed or 50% not decayed. This means the cat (if not watched) is in a same state: 50% dead and 50% alive. Just when you look inside the box, you know for sure.
This is how a quantum-system behaves. There exist superpositions of states (such as 50% dead [b]and[/b] 50% alive) and if you don't interact with the quantum system (a.k.a measuring = looking at it) it remains that way. Once you measure it, the wavefunction collapses to a certain value of dead [b]or[/b] alive. If you do multiple measurements, you'll later see that even if every single measurement resulted in dead or alive, the total distribution will again correspond to 50% being dead and 50% alive, coming from the 50% dead [b]and[/b] 50% alive state.
My cat had quantum kittens once, it was horrible trying to catch them and put them in a cage, because I knew how fast they were going, but not where they were...
:byodood:
[QUOTE=imasillypiggy;27847244]Cant we just say it has a 50% chance of being alive and a 50% dead. give or take accounting the exact chances that the cat will activate whatever will kill it.[/QUOTE]
it's a simple representation of a principle of quantum mechanics which is a wee bit more complicated than that
It's fine thought experiment so long as you consider it to be just that; a thought experiment. The whole idea of macroscopic superposition is the main thing people get worked up about. That and the fact that it's awfully hard to define observation.
[QUOTE=Jimjim32;27850222]It's fine thought experiment so long as you consider it to be just that; a thought experiment. The whole idea of macroscopic superposition is the main thing people get worked up about. That and the fact that it's awfully hard to define observation.[/QUOTE]
There are major implications to be derived from the concept. It impacts the notions of time, reality and even existence itself.
If you like Schrodinger's Cat you should get the Schrodinger's Kittens Book, Excellent Read. :buddy:
Schrodinger would use this to answer yes or no questions. How horrible is that
[QUOTE=miscreanity;27853928]There are major implications to be derived from the concept. It impacts the notions of time, reality and even existence itself.[/QUOTE]
Yeah, as of now, the way you interpret quantum mechanics is at the mercy of your own philosophical prejudices.
How coincidental. One of my friends was wearing this shirt today
[img_thumb]http://www.thinkgeek.com/images/products/zoom/d415_hello_schroddy.jpg[/img_thumb]
I found it incredibly entertaining. :v:
[QUOTE=Gmod4ever;27857666]How coincidental. One of my friends was wearing this shirt today
[img_thumb]http://www.thinkgeek.com/images/products/zoom/d415_hello_schroddy.jpg[/img_thumb]
I found it incredibly entertaining. :v:[/QUOTE]
Have to get this for my gf :)
[QUOTE=imasillypiggy;27847244]Cant we just say it has a 50% chance of being alive and a 50% dead. give or take accounting the exact chances that the cat will activate whatever will kill it.[/QUOTE]
No, quantum mechanics states the cat is both alive and dead simultaneously until we observe it and it is forced to take a specific state.
Avon stated it better though.
[QUOTE=miscreanity;27841559]unless someone rips it for posterity.[/QUOTE]
i'm on it.
[editline]4th February 2011[/editline]
[url]http://dl.dropbox.com/u/2116169/quantumkittens.m4a[/url]
[QUOTE=yawmwen;27858695]No, quantum mechanics states the cat is both alive and dead simultaneously until we observe it and it is forced to take a specific state.
Avon stated it better though.[/QUOTE]
So If I were to kill myself I would like to do it in this way. I could be alive and dead at the same time. Unless you say it wont work on humans. But that would be strange since it worked on cats which can also obverse junk.
[QUOTE=imasillypiggy;27860554]So If I were to kill myself I would like to do it in this way. I could be alive and dead at the same time. Unless you say it wont work on humans. But that would be strange since it worked on cats which can also obverse junk.[/QUOTE]
its a thought experiment. the point of it is that unless a quantum particle is observed, it is in both possible states at once. this isnt an actual experiment that can be conducted
[QUOTE=aVoN;27848820]Not entirely. It is put into a box, yes, with a radioactive element (just one single atom) and a poison. When the atom decays, a mechanism releases the poison and the cat dies.
The thing now is, the time of decay is totally random. When the time corresponding to the half-life passed, the atom has a chance to be 50% decayed or 50% not decayed. This means the cat (if not watched) is in a same state: 50% dead and 50% alive. Just when you look inside the box, you know for sure.
This is how a quantum-system behaves. There exist superpositions of states (such as 50% dead [b]and[/b] 50% alive) and if you don't interact with the quantum system (a.k.a measuring = looking at it) it remains that way. Once you measure it, the wavefunction collapses to a certain value of dead [b]or[/b] alive. If you do multiple measurements, you'll later see that even if every single measurement resulted in dead or alive, the total distribution will again correspond to 50% being dead and 50% alive, coming from the 50% dead [b]and[/b] 50% alive state.[/QUOTE]
Disclaimer: the experiment was never physically done as results providing proof either way are impossible - it's merely a thought experiment. Just in case anyone reading this is thinking we've seen cats in quantum superposition or something.
[QUOTE=Zeke129;27860639]Disclaimer: the experiment was never physically done as results providing proof either way are impossible - it's merely a thought experiment. Just in case anyone reading this is thinking we've seen cats in quantum superposition or something.[/QUOTE]
lol the fact they are in superposition means that we couldnt see them anyways, as soon as we saw them they would switch to their state
[QUOTE=imasillypiggy;27860554]So If I were to kill myself I would like to do it in this way. I could be alive and dead at the same time. Unless you say it wont work on humans. But that would be strange since it worked on cats which can also obverse junk.[/QUOTE]
It won't work on human or even cats. It was an [b]analogy[/b] to how a quantum-system can behave so much different from what you know of daily life. For this to work, your quantum-system must be coherently prepared. Every interaction (probing or interchanging energy) destroys coherence and the quantum-system collapses to a purely classical state. Since your body's atoms interact all time (chemical bonds, light from outside, heat etc), the coherence-time is very very very short, when not even negligible so you are in a totally classical state. (even that can't be totally generalized, but is sufficient for this explanation)
[QUOTE=blazingfly;27849028]My cat had quantum kittens once, it was horrible trying to catch them and put them in a cage, because I knew how fast they were going, but not where they were...
:byodood:[/QUOTE]
:golfclap:
[QUOTE=aVoN;27848820]Not entirely. It is put into a box, yes, with a radioactive element (just one single atom) and a poison. When the atom decays, a mechanism releases the poison and the cat dies.
The thing now is, the time of decay is totally random. When the time corresponding to the half-life passed, the atom has a chance to be 50% decayed or 50% not decayed. This means the cat (if not watched) is in a same state: 50% dead and 50% alive. Just when you look inside the box, you know for sure.
This is how a quantum-system behaves. There exist superpositions of states (such as 50% dead [b]and[/b] 50% alive) and if you don't interact with the quantum system (a.k.a measuring = looking at it) it remains that way. Once you measure it, the wavefunction collapses to a certain value of dead [b]or[/b] alive. If you do multiple measurements, you'll later see that even if every single measurement resulted in dead or alive, the total distribution will again correspond to 50% being dead and 50% alive, coming from the 50% dead [b]and[/b] 50% alive state.[/QUOTE]
How do we know that it is in both states at once and not just rapidly switching between them or some other explanation?
[QUOTE=Catdaemon;27873858]How do we know that it is in both states at once and not just rapidly switching between them or some other explanation?[/QUOTE]
The mathematical theory of quantum mechanics shows a quantum-system can be at both states at once. There mustn't be an oscillation how you describe it in that case. But QM does not forbid time-dependent oscillation (even in that case, it's not rapidly switching but smoothly, so it is - even with an oscillation - in both states at once during transition). Quantum-Interference experiments also showed this to be true. And without that, much stuff we are already using or have observed wouldn't work.
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