A possibly to ignorant question. Here I read:
For example, if she measures a $|0\rangle$,Bob must measure the same, as $|00\rangle$ is the only state where Alice's qubit is a $|0\rangle$
In the Quantum composer, with the "Bell State ZZ-Measurement" code, q0 and q1 are entagled but, changing the visualization seed (now at 6162), they have distinct measures.
Is this because 'higher correlation' doesn't mean 'identical values' or am I misinterpreting the basic elements?
Many thanks.
Perhaps the simplest way to observe verifiable entanglement between two parties $A$ and $B$ is to have them play the CHSH game. In this game, each player receives an input bit $x$ (resp. $y$) from a referee (also called the verifier), and each player must respond with an output bit $a$ (resp. $b$) to the referee.
Once the game begins, the parties cannot communicate and do not know the inputs given to the other player. The parties win if their outputs satisfy the predicate $a\oplus b=x\cdot y$, or in words, the XOR of their outputs is equal to the AND of their inputs.
One can show that the probability of $A$ and $B$ winning without entanglement between them is at best $3/4$. But if the parties share genuine entanglement, then there is a strategy that wins with probability $\cos^2(\pi/8)\approx 0.85$. Moreover, if they do win with this probability (the game may need to be played over and over to see this), then it can be shown that the parties must be employing genuine quantum correlations (i.e. entanglement).
