Hi, I am trying to read the chapter 2 of the book "Speakable and Unspeakable in Quantum Mechanics" from J. Bell. I have got some doubts and I would be glad if someone could help me.(adsbygoogle = window.adsbygoogle || []).push({});

I see that λ is a vector that makes the role of the hidden variable. All the tricks about the angles between a, a' and λ I think that I could understand.

Now some doubts:

The equation (1)

A(a, λ) = [itex]\mp[/itex] 1

means thatAmay take just 1 or - 1? So isAnot an average, but a measure itself ( like spin 1/2 or - 1/2), right?

In the equation (4)

sign λ.a'

Is it means sign( λ.a' ) ? And in this case the author is just saying that A(a, λ ) = sign( λ.a' ) ? And so is it in that sense that λ would define the result of the measure? If λ.a' > 0 the measure will show the spin up, otherwise spin down.

That is all for a while.

I will go on reading the rest of the chapter.

Thanks in advance.

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# Doubt in hidden variable concepts

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