# Physics

posted by .

Alice and Bob share a state a|++⟩+b|−−⟩, where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants a|+⟩+b|−⟩, what gate does he apply to his qubit in the following two cases? Choose your answer from I,X,Z,H.

When Alice's outcome was 0:
When Alice's outcome was 1:

• Physics - ENOUGH! -

• Physics -

I
X

• Physics -

I think the same, that in first case you don´t have to do anythin, and in the second case it´s a bit flip, but it is not correct, why? I think it´s because the sign basis used at the begining? So which could be the correct answer?

• Physics -

0 --I,H

• Physics -

what are the answers for 6th a and 6th b questions pls help me

## Similar Questions

1. ### quantum mechanics

Suppose we have a qubit in the state |ψ⟩=12|0⟩+3√2|1⟩. If we measure this qubit in |u⟩=3√2|0⟩+12|1⟩,|u⊥⟩=−12|0⟩+3√2|1⟩ basis, what is …
2. ### Physics

A two-qubit system was originally in the state 34|00⟩−5√4|01⟩+14|10⟩−14|11⟩, and then we measured the first qubit to be 0. Now, if we measure the second qubit in the standard basis, what …
3. ### Physics

A two-qubit system was originally in the state 34|00⟩−5√4|01⟩+14|10⟩−14|11⟩, and then we measured the first qubit to be 0. Now, if we measure the second qubit in the standard basis, what …
4. ### Quantum Physics

Alice and Bob share a state a|++> + b|-->, where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants his qubit in a|+> …
5. ### Physics

Suppose we have a one-qubit unitary U that maps |0⟩ to 13|0⟩+2−2i3|1⟩ and |1⟩ to 2+2i3|0⟩−13|1⟩. What is U?
6. ### Quantum Physics

Alice and Bob share a state a| + +> + b |- -> , where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants his qubit to …
7. ### Quantum Physics

Alice and Bob share a state a| + +> + b |- -> , where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants his qubit to …
8. ### Quantum Physics

Alice and Bob share a state a| + +> + b |- -> , where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants his qubit to …
9. ### physics

Alice and Bob share a state a|++>+b|−−>, where the first qubit is Alice's and the second qubit is Bob's. Alice measures her qubit in the standard basis and sends the measurement outcome to Bob. If Bob wants his qubit …
10. ### quantummechanics

The following circuit is designed for testing whether |u⟩=|v⟩. The three-qubit gate in the middle is called the controlled SWAP gate, which swaps the last two qubits if and only if the first qubit is 1 (a) If |u⟩=|v⟩=|+⟩, …

More Similar Questions

Post a New Question