Hi Mathieu,
Assuming Alice prepares a state in one basis and Bob measures in a different basis ,in half of these cases Bob sets yi= 1. You can see this in this map of possible scenarios attached. Hopefully this makes it clearer. Let me know if you still have more questions.
Assuming Alice prepares a state in one basis and Bob measures in a different basis ,in half of these cases Bob sets yi= 1. You can see this in this map of possible scenarios attached. Hopefully this makes it clearer. Let me know if you still have more questions.
Good luck,
Dina
