- #1
entropy1
- 1,232
- 72
In some popularized discussions of entanglement, you often hear that:
Now, if we assume like in the quote that particle B "has" spin-down, this agrees with observation. But it is still an assumption it seems to me, because what Bob measures in the second example is 50/50 spin-up and spin-down.
I am wondering if we should not confuse measurement with ontology in this case.
So I wonder if the formulation in the quote accurately reflects entanglement as a phenomenon. If not, entanglement may be more subtle to interpret.
EDIT: Likely we can describe entanglement more accurately with the wavefunction.
This seems to me not necessarily the case. In this formulation, particle A is viewed through measurement outcome and particle B through ontology. If the measurement basisses of Alice and Bob are parallel, Alice's outcome practically matches (the opposite of) Bob's. If the measurement basisses of Alice and Bob have a difference of 90 degrees, Alice's outcome is uncorrelated to Bob's. In the latter case if Alice measures spin-up, Bob will measure spin-up or spin-down with 50/50 probability (ie spin-right/spin-left).IF particle A is found to be spin-up, "we know that" particle B "has" spin-down.
Now, if we assume like in the quote that particle B "has" spin-down, this agrees with observation. But it is still an assumption it seems to me, because what Bob measures in the second example is 50/50 spin-up and spin-down.
I am wondering if we should not confuse measurement with ontology in this case.
So I wonder if the formulation in the quote accurately reflects entanglement as a phenomenon. If not, entanglement may be more subtle to interpret.
EDIT: Likely we can describe entanglement more accurately with the wavefunction.
Last edited: