In order to rotate the qubit state I need first to be able to read the values of $\alpha$ and $\beta$ and based on their values I will apply the Q-Gate for rotating the states of the single Qubits in the multi-qubit system I have.

Does anyone have an idea how to read these values?.

Using an Aer simulator reads the angles but only once, while I need to read and manipulate the states in a for loop so the simulator gives me the following error in the second run of the loop:

QiskitError: 'You have to select a circuit or schedule when there is more than one available'

  • $\begingroup$ Getting the values for $\alpha$ and $\beta$ in $\alpha|0\rangle + \beta|1\rangle$ (up to some arbitrary precision) requires quantum state tomography, which needs a large amount of copies of the state you want the amplitude of. $\endgroup$
    – epelaaez
    Sep 3, 2021 at 10:51
  • $\begingroup$ While @epelaaez answer seems right in principle, based on your QiskitError, the problem may just be that you are trying to access a single circuit in an array of circuits. Would you be able to post a link to the code ? $\endgroup$ Sep 3, 2021 at 12:17


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