I The Self-Decoherence of Schroedinger's Cat

[kered rettop]

A toy model might be to split the cat into two half-cats, each decohering the other. I'm intrigued by the idea that half-cat-1 is in a mixed state relative to half-cat-2 and vice versa. My question is, is there any reason to think that the actual cases observed by the two half-cats are going to be the same? We can open the box and look and we then, obviously (?) see the cat either alive or dead. All of it. Which would suggest that the two half-cat mixtures do actualise (?) the same way. (Is that reasonable?) But before the box is opened - how are the two observations guaranteed to match? Of course it might be more correct to say the two half-cats are entangled - |living>|living>+|dead>|dead> - but, in that case, self-decoherence doesn't get rid of the paradox, which is that "the wave function contains both cats".

 

[.Scott]

The Schroedinger's Cat story was intended to make a particular point. It doesn't extend too far.
I have often altered the story by noting that before the box is opened, by normal QM rules, those two possible cats would "interact"/"interfere" with each other. So perhaps you open the box and discover a cat that has recently feasted on its dead alternative.

 

[PeterDonis]

A toy model might be to split the cat into two half-cats, each decohering the other.

This doesn't work because each half-cat is already decohered even before we take into account its interactions with the other half-cat.

In order to even make sense of decoherence, you have to start with a quantum system that is coherent, and then look at how interactions with an environment decohere it. A half-cat isn't coherent to start with.

 

[Demystifier]

About self-decoherence of a cat see my https://arxiv.org/abs/1406.3221