Decoherence Clarification

[Feeble Wonk]

One philosophical comment is in order. Here the states of the observer are the states of his brain. How the brain creates a mind is an unresolved question, but QM is probably not essential for that.

Fair enough. We'll leave that aside for now. But it seems clear to me that there should be a logical correlation between the the "brain state" of the observer and the state of the opened box being observed, regardless of the potential philosophical issues.

 

[Demystifier]

But it seems clear to me that there should be a logical correlation between the the "brain state" of the observer and the state of the opened box being observed

Of course, and that correlation is encoded in the last state above that I have written. Rougly speaking, the quantum state
|DECAY>|DEAD>|see dead cat>+|NOT DECAY>|ALIVE>|see alive cat>
can be translated into a logical expression
(DECAY and DEAD and see dead cat) OR (NOT DECAY and ALIVE and see alive cat).

But one should be careful, because the translation is not reversible. In the reverse direction, an expression like
A OR B
gets translated into
a|A>+b|B>
where a and b are unknown coefficients.

 

[Feeble Wonk]

After opening the box it is
|DECAY>|DEAD>|see dead cat>+|NOT DECAY>|ALIVE>|see alive cat>

This seems to be somewhat of a slippery slope for me. When considering the observer+cat+atom in the "post-observation" status, would this be thought of as a "full" system... meaning a "pure" system in superposition... if we imagine that the universe consists of only these physical elements.

 

[Demystifier]

This seems to be somewhat of a slippery slope for me. When considering the observer+cat+atom in the "post-observation" status, would this be thought of as a "full" system... meaning a "pure" system in superposition... if we imagine that the universe consists of only these physical elements.

Yes. If you are now going to ask why do we not see a superposition, I will tell you that the answer depends on the interpretation.

 

[Feeble Wonk]

Yes. If you are now going to ask why do we not see a superposition, I will tell you that the answer depends on the interpretation.

[emoji39] You saw that coming a mile away. I've got some more thinking to do, and then I'd like to ask you more about how this relates to the SHV interpretation if that would be OK.

 

[Demystifier]

[emoji39] You saw that coming a mile away. I've got some more thinking to do, and then I'd like to ask you more about how this relates to the SHV interpretation if that would be OK.

Of course.