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StuckinbedtilDec t1_isq96ja wrote

Reply to comment by matpompili in Experimental demonstration of entanglement delivery using a quantum network stack by matpompili

Would the other side know exactly when the measurement was being conducted?

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matpompili OP t1_isqbrmy wrote

They could, it would not change the result. The measurement of the two spins gives correlated results, it does not change the result.

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StuckinbedtilDec t1_isqc9ia wrote

Then it is possible to send information by knowing exactly when the measurement was being conducted. As long as both groups have clocks that are synchronized then a 1/0 could be transferred based on the timing of the measurement.

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Suttonian t1_isqdtu3 wrote

Let's do the experiment.

  • Team A and Team B.
  • They agree that at exactly 10 am they will take measurements.
  • Team A gets a left spin, they know Team B has the opposite.
  • Team B gets a right spin, they know Team A has the opposite.

But what information has actually been transmitted? How could a message be transmitted?

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StuckinbedtilDec t1_isqgegx wrote

If team A takes a secret measurement at 10 am there's no way team B would know what time it was taken?

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Suttonian t1_isqryyy wrote

No there is no way for them to know if team A took a secret measurement.

If either side measures the entangled particle it will break the entanglement, the 'connection' is lost.

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StuckinbedtilDec t1_isqsxdp wrote

Could B team detect the moment a connection was lost?

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Suttonian t1_isqzspi wrote

No. Any detection/measurement results in the entanglement breaking.

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warplants t1_isr24mq wrote

No. The only possible way to know there was a connection in the first place is to compare the measurements of A and B teams; if their measurements are strongly correlated, there was a connection.

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