Schrodinger Cat Disproof (Samuel Jacobs)
Moderators: gmalivuk, Moderators General, Prelates

 Posts: 2
 Joined: Sun Sep 07, 2014 9:50 am UTC
Schrodinger Cat Disproof (Samuel Jacobs)
Proof that the Schrödinger's cat experiment cannot exist via contradiction.
Let there be a sample space which encompasses every object.
Let the sample space be divided into two sets which do not intersect each other and are called dead and alive.
A cat is placed into the box with the cyanide capsule which can go off any minute.
Schrodingers principle states that the cat cannot be either alive or dead until the box is opened and it is observed.
This means that the cat doesn't exist within the set dead, or the set alive, and so doesn't exist inside the sample space which encompasses every object. Which means that the cat doesn't exist.
But this is absurd, as the cat was put in the box before,
Ergo, schrodingers theory is disproved.
Q.E.D
Samuel Jacobs.
Let there be a sample space which encompasses every object.
Let the sample space be divided into two sets which do not intersect each other and are called dead and alive.
A cat is placed into the box with the cyanide capsule which can go off any minute.
Schrodingers principle states that the cat cannot be either alive or dead until the box is opened and it is observed.
This means that the cat doesn't exist within the set dead, or the set alive, and so doesn't exist inside the sample space which encompasses every object. Which means that the cat doesn't exist.
But this is absurd, as the cat was put in the box before,
Ergo, schrodingers theory is disproved.
Q.E.D
Samuel Jacobs.
 gmalivuk
 GNU Terry Pratchett
 Posts: 25789
 Joined: Wed Feb 28, 2007 6:02 pm UTC
 Location: Here and There
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
All you've shown is that there is at least one false premise. You want it to be the premise that the thought experiment is valid, but it could just as easily be your premise that 'dead' and 'alive' are disjoint and between them include everything.
I'd argue that that's a false premise even from a purely biological perspective, without ever having to bring quantum weirdness into it at all.
Another way to see how your argument is flawed is to note that it would disprove other quantum effects that have actually been observed, such as the double slit experiment (the sets are photons that go through the right slit and photons that go through the left) and entanglement (the sets are spin up and spin down particles, for example).
If your argument appears to disprove the most successfully and precisely confirmed scientific theory ever devised, your argument is probably wrong.
I'd argue that that's a false premise even from a purely biological perspective, without ever having to bring quantum weirdness into it at all.
Another way to see how your argument is flawed is to note that it would disprove other quantum effects that have actually been observed, such as the double slit experiment (the sets are photons that go through the right slit and photons that go through the left) and entanglement (the sets are spin up and spin down particles, for example).
If your argument appears to disprove the most successfully and precisely confirmed scientific theory ever devised, your argument is probably wrong.
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
SammySpicer wrote:Let the sample space be divided into two sets which do not intersect each other and are called dead and alive.
http://en.wikipedia.org/wiki/Begging_the_question
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
 ahammel
 My Little Cabbage
 Posts: 2135
 Joined: Mon Jan 30, 2012 12:46 am UTC
 Location: Vancouver BC
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
gmalivuk wrote:If your argument appears to disprove the most successfully and precisely confirmed scientific theory ever devised, your argument is probably wrong.
Wouldn't the argument just disprove the Copenhagen interpretation?
Follow up question: wasn't the Cat intended to show that there's something weird with the Copenhagen interpretation anyway?
He/Him/His/Alex
God damn these electric sex pants!
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
No, it was intended to show that you shouldn't take quantum mechanics too seriously. Which is wrong, you should, but decoherence happens in between the scale of atoms and cats. Schrodinger was not actually very good at quantum mechanics.
Regardless of interpretation, "alive" and "dead" are a basis for the sample space, they are not the entire sample space.
Regardless of interpretation, "alive" and "dead" are a basis for the sample space, they are not the entire sample space.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
As I understand it, in order for Schrodinger's Cat to be valid if actually carried out, the box would have to be so thoroughly isolated that not even so much as the state of a single photon outside the box could be affected by the cat's life or death before opening the box. Setting this up would be difficult.
 thoughtfully
 Posts: 2243
 Joined: Thu Nov 01, 2007 12:25 am UTC
 Location: Minneapolis, MN
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
douglasm wrote:As I understand it, in order for Schrodinger's Cat to be valid if actually carried out, the box would have to be so thoroughly isolated that not even so much as the state of a single photon outside the box could be affected by the cat's life or death before opening the box. Setting this up would be difficult.
I'm pretty sure you also have to cool the cat down to a pretty ridiculous fraction of a degree above absolute zero, to keep the poor cat from decohering itself. Which pretty much renders the whole exercise moot.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
"The cat is simultaneously alive and dead" also seems like the kind of trouble you can get into when you carelessly translate physics into everyday terms. "There are temporarily two cats, one alive and one dead" might not be a terrible alternate translation, and completely sidesteps the "disproof" here. If your contradiction hinges on which words you choose to qualitatively describe the math, it's not a very good disproof.
Basically, if you're "disproving" QM phenomena without looking at any actual QM, probably you're wasting your time.
Basically, if you're "disproving" QM phenomena without looking at any actual QM, probably you're wasting your time.
No, even in theory, you cannot build a rocket more massive than the visible universe.
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Meteoric wrote:"The cat is simultaneously alive and dead" also seems like the kind of trouble you can get into when you carelessly translate physics into everyday terms. "There are temporarily two cats, one alive and one dead" might not be a terrible alternate translation, and completely sidesteps the "disproof" here. If your contradiction hinges on which words you choose to qualitatively describe the math, it's not a very good disproof.
What no you shouldn't say that, there aren't two cats in classical OR quantum mechanics. In no set of physics laws do you get two cats.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?

 Posts: 555
 Joined: Tue Jun 15, 2010 1:31 pm UTC
Re: Schrodinger Cat Disproof (Samuel Jacobs)
I don't know that much QM, but isn't the alive/dead cat just a proxy for saying that the atom that triggers the poison gas is in a superposition of decayed and not decayed? Thus the cat itself is never actually in a superposition, even though it functionally is from the perspective of someone outside the box.
 Robert'); DROP TABLE *;
 Posts: 730
 Joined: Mon Sep 08, 2008 6:46 pm UTC
 Location: in ur fieldz
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Since the state of the cat's tightly correlated to that of the atom, either both or neither of them should be in superposition.
...And that is how we know the Earth to be bananashaped.
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
It's not that tightly correlated. There's a whole bunch of experimental apparatus in between; that is the resolution. The cat is only in a superposition if you do not decohere the superposition somewhere along the line.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
 Whizbang
 The Best Reporter
 Posts: 2238
 Joined: Fri Apr 06, 2012 7:50 pm UTC
 Location: New Hampshire, USA
Re: Schrodinger Cat Disproof (Samuel Jacobs)
thoughtfully wrote:douglasm wrote:As I understand it, in order for Schrodinger's Cat to be valid if actually carried out, the box would have to be so thoroughly isolated that not even so much as the state of a single photon outside the box could be affected by the cat's life or death before opening the box. Setting this up would be difficult.
I'm pretty sure you also have to cool the cat down to a pretty ridiculous fraction of a degree above absolute zero, to keep the poor cat from decohering itself. Which pretty much renders the whole exercise moot.
I once froze a cat to absolute zero. It was 0K.
 Quizatzhaderac
 Posts: 1510
 Joined: Sun Oct 19, 2008 5:28 pm UTC
 Location: Space Florida
Re: Schrodinger Cat Disproof (Samuel Jacobs)
You get two cats in the many worlds interpretation of QM.doogly wrote:In no set of physics laws do you get two cats.
The thing about recursion problems is that they tend to contain other recursion problems.
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Not really. "Counting" "branches" or "worlds" is too naive. State of the art Everett doesn't really do that.
(Not because it has really satisfying answers, of course; it just avoids repeating obviously problematic things.)
(Not because it has really satisfying answers, of course; it just avoids repeating obviously problematic things.)
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
gmalivuk wrote:If your argument appears to disprove the most successfully and precisely confirmed scientific theory ever devised, your argument is probably wrong.
In addition to this, I feel it important to point out that this is merely an analogy devised to explain quantum mechanics(which are quite unintuitive, IMO). Quantum mechanics isn't really about cats, this is just a way to attempt to explain quantum behavior in a more familiar setting. I think several previous posters were attempting to say something along this line as well, but I think it's worth being made explicit.
I do find it mildly amusing, though, when people assume QM is based on a whole bunch of mathmeticians overlooking some incredibly obvious bit of math.
 gmalivuk
 GNU Terry Pratchett
 Posts: 25789
 Joined: Wed Feb 28, 2007 6:02 pm UTC
 Location: Here and There
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
I wasn't talking about cats, I was talking about double slit and entanglement experiments.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Let there be a sample space which encompasses every object.
Let the sample space be divided into two sets which do not intersect each other and are called dead and alive.
This is the problem. The whole point of QM is that you can't make such a division. For any observable with two outcomes, the full space of states also contains linear combinations of the observable's eigenstates.
Alternatively, if you want to just randomly cut the space of states in two and call one piece "alive" and the other "dead" then there's no physical observable which distinguishes the two pieces.
Our universe is most certainly unique... it's the only one that string theory doesn't describe.
 Zamfir
 I built a novelty castle, the irony was lost on some.
 Posts: 7302
 Joined: Wed Aug 27, 2008 2:43 pm UTC
 Location: Nederland
Re: Schrodinger Cat Disproof (Samuel Jacobs)
doogly wrote:It's not that tightly correlated. There's a whole bunch of experimental apparatus in between; that is the resolution. The cat is only in a superposition if you do not decohere the superposition somewhere along the line.
Could you explain how a coherent and a decoherent amplifier (catbased or otherwise) would differ from each other?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
gmalivuk wrote:I wasn't talking about cats, I was talking about double slit and entanglement experiments.
Sorry, talking to the OP, but agreeing with/expanding upon your response. Didn't make that adequately clear, I think.
In short, in focusing on the cat, he's...entirely missing the point of the analogy.
 ahammel
 My Little Cabbage
 Posts: 2135
 Joined: Mon Jan 30, 2012 12:46 am UTC
 Location: Vancouver BC
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Clive wrote: I understand the physics. I understand the dead cat.
Larry wrote:You understand the dead cat? But... you... you can't really understand the physics without understanding the math. The math tells how it really works. That's the real thing; the stories I give you in class are just illustrative; they're like, fables, say, to help give you a picture. An imperfect model. I mean  even I don't understand the dead cat. The math is how it really works.
Clive wrote:Very difficult...
He/Him/His/Alex
God damn these electric sex pants!
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Precisely. And the math is far from trivial. Even a brief perusal of it should convince anyone that the sort of folks who crunch those numbers have probably heard of basic set theory.
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
It is fairly complicated, http://en.wikipedia.org/wiki/Quantum_amplifier
but it seems to be mostly a question of degree. To keep it coherent, you need all sorts of http://en.wikipedia.org/wiki/Quantum_error_correction
but it seems to be mostly a question of degree. To keep it coherent, you need all sorts of http://en.wikipedia.org/wiki/Quantum_error_correction
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
thoughtfully wrote:douglasm wrote:As I understand it, in order for Schrodinger's Cat to be valid if actually carried out, the box would have to be so thoroughly isolated that not even so much as the state of a single photon outside the box could be affected by the cat's life or death before opening the box. Setting this up would be difficult.
I'm pretty sure you also have to cool the cat down to a pretty ridiculous fraction of a degree above absolute zero, to keep the poor cat from decohering itself. Which pretty much renders the whole exercise moot.
If the cat was totally isolated from the external environment until it was measured, and the final measurement looked at every particle in the box (possibly with the experiment repeated many times with duplicate cats starting in the same quantum state when the box was sealed, so one could look at the statistics of different outcomes), wouldn't there be indicators the system had been in superposition that couldn't be explained if you just assumed a classical statistical mixture of alive + dead, regardless of the temperature?
An idea that occurred to me would be to do a variant of the the delayed choice quantum eraser where the "signal" photon would leave the box from one of two slits and hit a screen, and the "idler" would remain inside, and depending on which slit the signal photon exited through the idler would either take a path that would cause it to trigger a device that would kill the cat, or it would take a different path that left the device untriggered. If the box was left sealed for some vast amount of time, enough so that when the box was opened its contents would be at maximum entropy, there would be no way to tell whether the cat had been killed by the device or whether it had lived a long life and died of natural causesthe information about the path taken by the idler (and thus which slit the signal photon had exited from) would have been "erased", just as in the delayed choice quantum eraser. So in analogy with that experiment, if this hypothetical experiment could be repeated a large number of times (with the cat inside the box being prepared in the exact same quantum state each time, and the contents of the box being measured with maximum possible precision when it was opened), shouldn't it be possible to recover an interference pattern in the statistics of signal photons on the screen, by looking at only some subset of signal photons that had hit the screen on trials where the contents of the box were in some particular end state? If so, saying "the cat was really alive or dead on each trial in that subset, we just don't know which" would be equivalent to saying "the photon really passed through either the left or right slit, we just don't know which".

 Posts: 2
 Joined: Sun Sep 07, 2014 9:50 am UTC
Re: Schrodinger Cat Disproof (Samuel Jacobs)
gmalivuk wrote:All you've shown is that there is at least one false premise. You want it to be the premise that the thought experiment is valid, but it could just as easily be your premise that 'dead' and 'alive' are disjoint and between them include everything.
I'd argue that that's a false premise even from a purely biological perspective, without ever having to bring quantum weirdness into it at all.
Another way to see how your argument is flawed is to note that it would disprove other quantum effects that have actually been observed, such as the double slit experiment (the sets are photons that go through the right slit and photons that go through the left) and entanglement (the sets are spin up and spin down particles, for example).
If your argument appears to disprove the most successfully and precisely confirmed scientific theory ever devised, your argument is probably wrong.
Please answer me two questions,
1. How can dead and alive ever intersect each other in purely biological terms, nothing can exist in both at the same time.
2. I realise that Schrodinger's cat was an example on the absurdity of the underlying theory behind it, but it is still a perfectly valid example of it. Please tell me how my premises are flawed, either axiomatically, or via reference to any accepted scientific experiment, or mathematical proof.
I am confused as to how you can find any fault in my completely reasonable assumptions, but I am open minded to any reasonable argument from you, if you are able to demonstrate one.
 gmalivuk
 GNU Terry Pratchett
 Posts: 25789
 Joined: Wed Feb 28, 2007 6:02 pm UTC
 Location: Here and There
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Have you read a single post in this entire thread?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
SammySpicer wrote:Please answer me two questions,
1. How can dead and alive ever intersect each other in purely biological terms, nothing can exist in both at the same time.
Because if we want to define "alive" and "dead" in physical terms, we would normally think of them in terms of different spatial configurations of particlesfor example, a cat that's been dead for a while won't have the same oxygen levels in its cells as a live one, the membranes of its neurons would no longer be polarized, etc. But some "quantum states" involve all the particles spread out over a range of possible positions (assigning nonzero amplitudes to a range of different position eigenstates). If you measured some other nonposition variables and found the system in some quantum state S1, and then immediately afterwards made a precise measurement of the position of all the particles in the box, according to the quantum rules this would put the system in a new quantum state S2 which was a position eigenstate, with the probability of getting a given position eigenstate proportional to the square of the amplitude assigned to that eigenstate by the first state S1. For some choices of S1, there might be a 50% chance that the position measurement would give a new state S2 whose configuration would be labeled "live cat", and a 50% chance it would give a new state S2 whose configuration would be labeled "nonliving remains of a cat". In such a case, how should we classify the first state S1, given that in this state the atoms simply don't have a definite position configuration, and if we immediately measure their position there is a 50% chance of finding a configuration that's a live cat and a 50% chance of finding one that's the nonliving remains of a cat?
 Angua
 Don't call her Delphine.
 Posts: 5652
 Joined: Tue Sep 16, 2008 12:42 pm UTC
 Location: UK/[St. Kitts and] Nevis Occasionally, I migrate to the US for a bit
Re: Schrodinger Cat Disproof (Samuel Jacobs)
I realise this is slightly missing the point of the thread, but still.
What is the definition of life?
Is a virus dead or alive?
Is a prion dead or alive?
Is a self replicating program dead or alive?
What is the definition of death?
When do you class something as being dead?
Does brainstem death count as being dead?
What is the definition of life?
Is a virus dead or alive?
Is a prion dead or alive?
Is a self replicating program dead or alive?
What is the definition of death?
When do you class something as being dead?
Does brainstem death count as being dead?
'Look, sir, I know Angua. She's not the useless type. She doesn't stand there and scream helplessly. She makes other people do that.'
GNU Terry Pratchett
 Zamfir
 I built a novelty castle, the irony was lost on some.
 Posts: 7302
 Joined: Wed Aug 27, 2008 2:43 pm UTC
 Location: Nederland
Re: Schrodinger Cat Disproof (Samuel Jacobs)
doogly wrote:It is fairly complicated, http://en.wikipedia.org/wiki/Quantum_amplifier
but it seems to be mostly a question of degree. To keep it coherent, you need all sorts of http://en.wikipedia.org/wiki/Quantum_error_correction
This what I deduced from wikiing around:
The state of a qubit needs two real numbers to be described, analogous to a spherical coordinate system. Might be 2 complex numbers plus some normalization, or two angles, etc. If you know the state, you can calculate the probability that a certain measurement will yield a '1' or '0' outcome. That probability itself could be used as one of the numbers to describe the state of the qubit, but then you still need another number as well , something like a phase angle.
If you describe qubits only with such probabilities, you will be tempted to use the laws of probability to calculate the effect of interactions between qubits. This will give wrong results for some situations, seemingly paradoxical.
Next, a quantum amplifier is some largish set of qubits that with tightly correlated states, and where the evolution of those states stays correlated .This is hard to pull off. AFAICT, you can only correlate full quantum states with other quantum states . You cannot, even in principle, build an amplifier that teases the qubit state apart so that two dials each show one of the angles that together describe the state of the qubit. But I am fuzzy on this aspect.
Now, Schrödinger's cat, where I am getting even fuzzier. At its core is a nucleus that might decay. I don't know if that could be interpreted as a single qubit? Even if it is, then the original description of the experiment does not aim to correlate the cat with the entire quantum state of the qubit. There is a probability of a dead cat, but no phases.
If I get this right, then there is no reason to treat the box with cat as a quantum system. You can think classically, 'the cat is either dead or alive with probability X', and every experiment will give unsurprising results from that POV. Unlike a qubit, where you can see surprising results. But someone with mad skilzz and liquid helium might conceivably build a macroscopic system that correlates with the complete quantum state of of a qubit. Such a system could only be described as being in A and B at the same time, for states A and B that we hot humans can observe. But it's less clear that such a cold and slow system could have meaningful 'dead' and 'alive' states.
Is this wikideduction somewhat correct?
 doogly
 Dr. The Juggernaut of Touching Himself
 Posts: 5212
 Joined: Mon Oct 23, 2006 2:31 am UTC
 Location: Somerville, MA
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Yes excellent very good.
LE4dGOLEM: What's a Doug?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
Noc: A larval Doogly. They grow the tail and stinger upon reaching adulthood.
Keep waggling your butt brows Brothers.
Or; Is that your eye butthairs?
 Zamfir
 I built a novelty castle, the irony was lost on some.
 Posts: 7302
 Joined: Wed Aug 27, 2008 2:43 pm UTC
 Location: Nederland
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Thanks. A last question:
In the original thought experiment, the quantum event is a decaying nucleus. To my untrained eyes, such an event feels rather big and irreversible, compared to textbook examples of quantum states, like spin directions or electron energy levels. Is that right? Or are there real life experiments where a nucleus is clearly in a superposition with its decayed version, leading to some sort of interference effect?
In the original thought experiment, the quantum event is a decaying nucleus. To my untrained eyes, such an event feels rather big and irreversible, compared to textbook examples of quantum states, like spin directions or electron energy levels. Is that right? Or are there real life experiments where a nucleus is clearly in a superposition with its decayed version, leading to some sort of interference effect?
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Zamfir wrote:If I get this right, then there is no reason to treat the box with cat as a quantum system. You can think classically, 'the cat is either dead or alive with probability X', and every experiment will give unsurprising results from that POV. Unlike a qubit, where you can see surprising results. But someone with mad skilzz and liquid helium might conceivably build a macroscopic system that correlates with the complete quantum state of of a qubit. Such a system could only be described as being in A and B at the same time, for states A and B that we hot humans can observe. But it's less clear that such a cold and slow system could have meaningful 'dead' and 'alive' states.
As I said in my comment to thoughtfully, I don't think it's actually necessary to the thoughtexperiment that the system be cold, although if we wanted to correlate a macro system with a qbit in practice it would have to be cold to prevent decoherence from interactions with the external environment. But just as a thoughtexperiment, if we imagine some scifi force field that can completely isolate the cat from decohering interactions with the environment outside the box (which no realistic box at room temperature could do), and we also have a way to measure the complete quantum state of all the particles inside the box at the instant we open it (as opposed to just a coarsegrained macro measurement), and we have the capability to repeat the experiment many times with the contents of the box including the cat being prepared in precisely the same quantum state at the start of each one, then in principle I think the statistics of different end states would show correlations that would demonstrate the macro system was entangled with the qbit.
Another point is that a warm but completelyisolatedfromtheexternalenvironment system might not be possible to create in practice, but if we had a sufficiently large quantum computer it should be possible to simulate such a system using a set of (cold) entangled qbits, since a quantum computer is supposed to be able to simulate any physically possible quantum system (much more efficiently than a classical computer).
 ahammel
 My Little Cabbage
 Posts: 2135
 Joined: Mon Jan 30, 2012 12:46 am UTC
 Location: Vancouver BC
 Contact:
Re: Schrodinger Cat Disproof (Samuel Jacobs)
"Dead" and "alive" are not welldefined in purely biological terms.SammySpicer wrote:1. How can dead and alive ever intersect each other in purely biological terms, nothing can exist in both at the same time.
One of your premises is that the cat cannot be dead and alive at the same time. It is not terribly surprising that from this premise, you can derive the conclusion that the cat cannot be dead and alive at the same time.2. I realise that Schrodinger's cat was an example on the absurdity of the underlying theory behind it, but it is still a perfectly valid example of it. Please tell me how my premises are flawed, either axiomatically, or via reference to any accepted scientific experiment, or mathematical proof.
I am confused as to how you can find any fault in my completely reasonable assumptions, but I am open minded to any reasonable argument from you, if you are able to demonstrate one.
He/Him/His/Alex
God damn these electric sex pants!
Re: Schrodinger Cat Disproof (Samuel Jacobs)
I am confused as to how you can find any fault in my completely reasonable assumptions, but I am open minded to any reasonable argument from you, if you are able to demonstrate one.
As was pointed out, one of your assumptions is that "Dead" and "Alive" are disjoint sets whose union is the entire space of states. This is simply not the case in quantum mechanics. There is also a whole plethora of "superposition" states. You should not think of these states as "the cat is both dead and alive simultaneously" in the usual set theory sense. These are NOT states which are in the intersection of "Dead" and "Alive", there is no such intersection by assumption. Rather these are additional states which have the peculiar property that repeated interactions with researchers (using a brand new radioactive sample each time and resurrecting the cat if need be) leads to a statistical distribution of outcomes rather than the same answer over and over.
So now you can ask "How can superpositions exist? Why don't "Dead" and "Alive" exhaust my space of states?" which seems like a "completely reasonable" thing to say because we only ever see live cats or dead cats. One answer is to just point to the body of experimental evidence for QM and say "yeah, I dunno, it's kinda weird, but true, get used to it". Another is to point out that your assumption isn't as reasonable as you say to begin with. The fact that we only ever see live of dead cats only allows us to say that our interactions with cats only ever leave us with the perception of a live cat or a dead cat. This could be because "dead" and "alive" are the only two states the cat is ever in, but it also could be that the dynamics of the universe are such that the cat's interactions with the rest of the universe, and especially with us during our observation of them, tend to quickly shove them into the vicinity of those states and tend to keep them there, thus hiding a huge extra set of weirder states from our everyday experience. Both of these alternatives look the same to us in everyday life, so which one is true becomes an empirical question to be studied in more exotic experimental settings. That's where we point to the body of experimental evidence for QM and say "oh, I guess it's that second case... kinda weird, but true, get used to it".
Our universe is most certainly unique... it's the only one that string theory doesn't describe.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Zamfir wrote:Thanks. A last question:
In the original thought experiment, the quantum event is a decaying nucleus. To my untrained eyes, such an event feels rather big and irreversible, compared to textbook examples of quantum states, like spin directions or electron energy levels. Is that right? Or are there real life experiments where a nucleus is clearly in a superposition with its decayed version, leading to some sort of interference effect?
i think that the point is that the decay of a single nucleus can not be predicted, it is truly random. thus, you cannot possibly know the state of the system without observing it.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Honestly, I don't know how this thread survived the first reply. GM seemed to shoot it down when he mentioned that this 'argument' would 'disprove' the doubleslit experiment.
Here's an attempt to construct that argument, using exactly the same wording as best I can:
As with the original 'argument', there are many criticisms that could be made, but the most damning is that the experiment has been done! Photons created one at a time still produce an interference pattern, meaning they, in some sense, do go through both slits at once, and so very definitely don't have just a single direction of travel.
Here's an attempt to construct that argument, using exactly the same wording as best I can:
Let there be a sample space which encompasses every direction a photon could go.
Let the sample space be divided into three sets which do not intersect each other and are called '(went through the) left slit', 'right slit' and 'neither slit'
A photon is created.
QM states that the photon hasn't gone in one single direction unless we observe it
This means that the photon doesn't exist within the set 'left slit', 'right slit' or 'neither slit' and so doesn't exist inside the sample space which encompasses every direction. Which means that the photon doesn't exist.
But this is absurd, as the photon was created.
Ergo, QM is disproved.
Q.E.D
As with the original 'argument', there are many criticisms that could be made, but the most damning is that the experiment has been done! Photons created one at a time still produce an interference pattern, meaning they, in some sense, do go through both slits at once, and so very definitely don't have just a single direction of travel.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
ahammel wrote:"Dead" and "alive" are not welldefined in purely biological terms.SammySpicer wrote:1. How can dead and alive ever intersect each other in purely biological terms, nothing can exist in both at the same time.One of your premises is that the cat cannot be dead and alive at the same time. It is not terribly surprising that from this premise, you can derive the conclusion that the cat cannot be dead and alive at the same time.2. I realise that Schrodinger's cat was an example on the absurdity of the underlying theory behind it, but it is still a perfectly valid example of it. Please tell me how my premises are flawed, either axiomatically, or via reference to any accepted scientific experiment, or mathematical proof.
I am confused as to how you can find any fault in my completely reasonable assumptions, but I am open minded to any reasonable argument from you, if you are able to demonstrate one.
Another scientific theory disproven by the living dead, of course.
 WibblyWobbly
 Can't Get No
 Posts: 506
 Joined: Fri Apr 05, 2013 1:03 pm UTC
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Tyndmyr wrote:ahammel wrote:"Dead" and "alive" are not welldefined in purely biological terms.SammySpicer wrote:1. How can dead and alive ever intersect each other in purely biological terms, nothing can exist in both at the same time.One of your premises is that the cat cannot be dead and alive at the same time. It is not terribly surprising that from this premise, you can derive the conclusion that the cat cannot be dead and alive at the same time.2. I realise that Schrodinger's cat was an example on the absurdity of the underlying theory behind it, but it is still a perfectly valid example of it. Please tell me how my premises are flawed, either axiomatically, or via reference to any accepted scientific experiment, or mathematical proof.
I am confused as to how you can find any fault in my completely reasonable assumptions, but I am open minded to any reasonable argument from you, if you are able to demonstrate one.
Another scientific theory disproven by the living dead, of course.
Zombies make especially good string theorists, of course  they're always looking for branes.
I'm so very sorry for that.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Hi, I did not go thru the whole thread so maybe I'll say something redundant.
The main premise of the experiment is that the cat can be isolated. It takes 500 light years of lead to stop 50% of the natural neutrino flux.
So one cannot isolate the cat before it makes a black hole...
So when mind experiments outpass the physical possibilities of the universe, maybe there is some hidden law that we ignore.
The main premise of the experiment is that the cat can be isolated. It takes 500 light years of lead to stop 50% of the natural neutrino flux.
So one cannot isolate the cat before it makes a black hole...
So when mind experiments outpass the physical possibilities of the universe, maybe there is some hidden law that we ignore.
Re: Schrodinger Cat Disproof (Samuel Jacobs)
Paragraph 2: Yes, neutrinos present a nonfundamental limit on the size*duration of a coherent state. However, neutrinos do not interact rapidly with the cat (to put it mildly), so this degradation will not be very quick. Easily long enough to perform the experiment and run up against much more fundamental limits of the problem
Paragraph 3: I have no idea what 'black hole' is doing here.
Paragraph 4: As noted above, this is nonfundamental, and the questions the problem seeks to probe are far more fundamental.
Paragraph 3: I have no idea what 'black hole' is doing here.
Paragraph 4: As noted above, this is nonfundamental, and the questions the problem seeks to probe are far more fundamental.
Who is online
Users browsing this forum: No registered users and 14 guests