0

I'm having a hard time understanding why it is not possible to communicate faster than light with entangled qubits. Now, this is my hypothesis.

A and B have a pair of qubits, and 2 synced clocks at 12:00. Now A and B agree that every 5 minutes, B will observe his qubit (at 12:05 ; 12:10 ; ....), to see whether it is in state 1 or 0. A will prepare an X gate and a CNOT gate and let's say A's qubit is the control qubit and B's qubit is the target qubit. B will also know which gates A is using to manipulate the control qubit. And so, B goes somewhere very very far away with one of the synced clocks. Now, both qubits are in the initial state (00), if A wants to send to B the state 0, A does not have to do anything. And if A wants to send to B state 1, A will apply the X gate to his qubit, resulting (10), and put those through a CNOT gate, which will result in the state (11), so B with his target qubit will see (1).

Recall that we have 2 synced clocks, at 12:00 and B will measure his qubit every 5 minutes. The reason for the synced clock is for B to know when to measure his qubit, so his measurement does not occur before A, which will mess up the whole communication purpose. And for A, having a 5-minute rest time between each measurement can help him reset the control qubit to state (0) and decide whether to use the X gate or just put the qubit through the CNOT gate. (So by using the X gate and CNOT, A will control what B receives).

As I said, I'm having a hard time understanding the topic so there might be a fundamental mistake so please tell me.

1 Answers1

3

If Alice is performing a CNOT on her and Bobs qubits, Bob (and his qubit) will need to be close to Alice.

No matter how they prepare the state, once they are separated, local operations will not affect measurement distributions for the other persons qubit.

john
  • 46
  • 1