Schrödingers cat, is it just mumbo-jumbo?

[kered rettop]

If, owing to decoherence, the wavefunction superposition is experimentally indistinguishable from a simple classical either/or probability, then it's not ridiculous.

Well, you'll have to take it up with Schroedinger because he gave the cat scenario as an example of a "quite ridiculous case". If you want to say that his scenario is flawed because we now know about decoherence, I would agree with you. That said, this particular flaw is quite easily fixed by making the box big enough so that everything which gets entangled with the cat remains inside the box. Obviously a faster trigger would make it more practical, otherwise the box would have to reach to Saturn.

 

[PeterDonis]

this particular flaw is quite easily fixed by making the box big enough so that everything which gets entangled with the cat remains inside the box

No, that doesn't change anything. The cat is already a macroscopic object and decoheres itself, so the box in the original thought experiment is already big enough to allow decoherence.

 

[kered rettop]

No, that doesn't change anything. The cat is already a macroscopic object and decoheres itself, so the box in the original thought experiment is already big enough to allow decoherence.

The question is not whether the box allows decoherence. The question is whether the box can contain everything affected by decoherence. (That includes everything in the environment that interacts with the cat.) If it can't then the box contains a mixture (as suggested by PeroK) instead of a pure state. This would defeat the point of Schroedinger's scenario, making it seriously flawed. By making the box vast, the entire interacting system - cat stuff and environment stuff - remains inside the box and Schroedinger's scenario is patched up.

 

[PeterDonis]

The question is not whether the box allows decoherence. The question is whether the box can contain everything affected by decoherence.

Sure it can. It contains the cat and the environment the cat interacts with. That's everything. By hypothesis the box is an isolated system until it is opened, so there is no interaction between inside and outside.

 

[kered rettop]

Sure it can. It contains the cat and the environment the cat interacts with. That's everything. By hypothesis the box is an isolated system until it is opened, so there is no interaction between inside and outside.

Yes I agree with that. I was just trying to make sure that we can keep the required isolation. I prefer a physically possible box but one that isolates by hypothesis would do.