Suppose we have two qubits in the state α|00⟩+β|11⟩.

Question

(a) If we measure the first qubit in the sign basis, what is the probability of seeing a +?
(b) What is the resulting state of the second qubit in that case? Use a and b to denote α and β respectively.(b) What is the resulting state of the second qubit in that case? Use a and b to denote α and β respectively.

Answer 1

(a)0.5