Bohmian interpretation of Schrodinger's Cat

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  • #1
sillyputty
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[Moderator's note: Thread spun off due to interpretation discussion.]

PeterDonis said:
|atom decayed⟩|cat dead⟩+|atom not decayed⟩|cat alive⟩

Many pop science sources will describe the cat as being "in a superposition of dead and alive", but that is not really correct. The cat is entangled with the atom; that is the correct description (or at least the best you can do in ordinary language).
But if the cat was in a box with a double slit rig inside the box as well, and if the cat lives if the atom goes left, and if the cat dies if the atom goes right, then you could say the cat is in a superposition of dead and alive (and be correct saying it). That is because there exists the Bohmian interpretation. But my question is this: How can the existence of an interpretation enable that you're correct in speaking that way, unless it was true, that what makes you incorrect in speaking that way, is some other kind of interpretation?
 
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  • #2
sillyputty said:
if the cat was in a box with a double slit rig inside the box as well, and if the cat lives if the atom goes left, and if the cat dies if the atom goes right, then you could say the cat is in a superposition of dead and alive (and be correct saying it). That is because there exists the Bohmian interpretation.
Not at all; in the Bohmian interpretation the cat is not in any such superposition, because nothing ever is! The cat's actual, physical state in the Bohmian interpretation depends on the positions of all its particles, and those are never in superposition: particle positions in the Bohmian interpretation are always definite and single-valued. Any "superposition" is in the wave function (or quantum potential in Bohmian terms), which exerts a nonlocal influence on how particle positions change with time, but which has nothing to do with the actual, physical state of cats or anything else.
 
  • #3
PeterDonis said:
Not at all; in the Bohmian interpretation the cat is not in any such superposition, because nothing ever is!

Fair enough, but all that changes is this: Instead of saying the Cat is in superposition, we say the Cat and particle have definite state, even though which way the particle goes is entirely governed by the wave function. So the cat has a 50% chance dying or staying alive. This is not different (except cosmetically) from where the cat faces a decaying atom. Case1: You put a cat in box with atom that decays OR not, determined by wave func. Cat waits for it. Case2: You put cat in box with atom that goes left or right slit, determined by wave func. Cat waits for it. They are the same hypothetical. The difference is that only one of them is subject to being treated by the Bohmian interpretation. But since (aside from that) they are the same hypothetical, it took just an interpretation (Bohmian) to dispose of the entire issue (issue of: cat dead or alive!, how do we word this??). The cat is EITHER going to die or is going to live, determined by the wave func. My point is: If a mere interpretation can cause the issue to NOT exist, then (where cat is with atom that decays/or not), it must be some kind of interpretation causing the issue TO exist.
 
  • #4
sillyputty said:
The difference is: only one of them is subject to being treated by the Bohmian interpretation.
I don''t know what you mean by this. The Bohmian interpretation can treat any scenario that can be treated by standard QM.
 
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  • #5
PeterDonis said:
I don''t know what you mean by this. The Bohmian interpretation can treat any scenario that can be treated by standard QM.
OK then treat the cat scenario with Bohmian, and your issue is gone. No need to say things like "cat dead and alive" or "the only strictly correct language is to say this". All that is unnecessary because you can just apply Bohmian, to this cat situation. And if you don't, then it means you are applying some kind of interpretation in place of Bohmian.
 
  • #6
sillyputty said:
treat the cat scenario with Bohmian, and your issue is gone
In the sense that the cat itself is never claimed to be in a superposition of dead and alive, yes.

sillyputty said:
No need to say things like "cat dead and alive" or "the only strictly correct language is to say this".
If you're talking about basic QM, without adopting any specific interpretation, then you can't say anything that depends on a particular interpretation.

sillyputty said:
you can just apply Bohmian, to this cat situation. And if you don't, then it means you are applying some kind of interpretation in place of Bohmian.
No, you could just be using basic QM, without adopting any specific interpretation. That is sufficient to derive experimental predictions. In the thread from which this one was spun off, the topic was what experimental predictions are made and what mathematical model is used to make them. (And note that that thread was not specifically about the Schrodinger's cat thought experiment.)
 
  • #7
sillyputty said:
My point is: If a mere interpretation can cause the issue to NOT exist,
The interpretation does not imply that the issue does not exist. The interpretation implies that the issue does not exist in that interpretation.
 
  • #8
Demystifier said:
The interpretation does not imply that the issue does not exist. The interpretation implies that the issue does not exist in that interpretation.
I think his point was that if the issue exist only in some interpretations, then it is not an issue.
 
  • #9
martinbn said:
I think his point was that if the issue exist only in some interpretations, then it is not an issue.
The counterpoint is that you can't have all interpretations at the same time. Unlike the cat, however, you get to choose your poison!
 
  • #10
PeroK said:
The counterpoint is that you can't have all interpretations at the same time. Unlike the cat, however, you get to choose your poison!
Do you have to choose an interpretation? And if you do, do you have to view it as an accurate description? May be interpretations are just that. An incomplete, inaccurate, and sometimes wrong attempt to phrase QM in ordinary language.
 
  • #11
martinbn said:
Do you have to choose an interpretation?
I don't see why. You could take QM at its mathematical face value. That's closest to my personal view, in fact.
 
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  • #12
Since the OP is now on an unplanned vacation, this thread is closed.
 
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