- #1
Q-reeus
- 1,115
- 3
I'd like some informed opinion on the following scenario, which in a certain article forms the basis of a controversial claim.
Suppose an entangled spin anti-correlated pair of particles are generated by some process. Particle A flies off along the +z direction, particle B along the -z direction. In particle A's path are placed three consecutively spaced spin detectors. The first measures say along the x axis, the second along the y axis, the third along the x-axis again. We can choose to measure particle B's spin either after the first, second, or third measurement performed on particle A. Is it the case that entanglement ceases after the first measurement on A, in which case particle B's spin will always be measured as the opposite of the first x-axis measurement on A, regardless of subsequent measurements on A. Or does entanglement survive until particle B is actually measured, in which case presumably it could have the anti-correlated value of particle A's second or third measurement, depending on just when measurement on B is performed?
Suppose an entangled spin anti-correlated pair of particles are generated by some process. Particle A flies off along the +z direction, particle B along the -z direction. In particle A's path are placed three consecutively spaced spin detectors. The first measures say along the x axis, the second along the y axis, the third along the x-axis again. We can choose to measure particle B's spin either after the first, second, or third measurement performed on particle A. Is it the case that entanglement ceases after the first measurement on A, in which case particle B's spin will always be measured as the opposite of the first x-axis measurement on A, regardless of subsequent measurements on A. Or does entanglement survive until particle B is actually measured, in which case presumably it could have the anti-correlated value of particle A's second or third measurement, depending on just when measurement on B is performed?