Bell's Theorem - why product of (2)spins can be +1 (Griffith's text)

[Sparky_]

TL;DR Summary

Table of products of the spin of electron and positron shows the product can be +1

Hello,

Within Griffith's text - chap 12 section 12.2 page 423 - this is a brief summary of Bell's Theorem and description of Bell's 1964 work.

There is a table on page 423 showing the spin of the electron and positron (from pi meson decay) - these would be in the singlet state, one would be spin up and the other spin down

the table has some rows showing both having spin up or both having spin down so the product is +1

I don't see (yet) how you can have the product be +1

I feel like it is because the detectors are not fixed

Figure 12.2 (page 424) shows a diagram of the experiment - where the two detectors' orientation is shown to be free.

There is not enough detail describing the detectors nor what happens when they rotate past horizontal -

will a detector give the negative result if it is upside down - (or it's unit vector has a component pointing down)?

Thanks
-Sparky

 

[PeroK]

Summary:: Table of products of the spin of electron and positron shows the product can be +1

Hello,

Within Griffith's text - chap 12 section 12.2 page 423 - this is a brief summary of Bell's Theorem and description of Bell's 1964 work.

There is a table on page 423 showing the spin of the electron and positron (from pi meson decay) - these would be in the singlet state, one would be spin up and the other spin down

the table has some rows showing both having spin up or both having spin down so the product is +1

I don't see (yet) how you can have the product be +1

I feel like it is because the detectors are not fixed

Figure 12.2 (page 424) shows a diagram of the experiment - where the two detectors' orientation is shown to be free.

There is not enough detail describing the detectors nor what happens when they rotate past horizontal -

will a detector give the negative result if it is upside down - (or it's unit vector has a component pointing down)?

Thanks
-Sparky

That table records the two spin measurements about the respective axes. The product is simply the product of two numbers. Nothing more.