On reading observations of m_0 for intermediate measurements

> def my_quantum_function(x, y):
>     qml.RY(x, wires=0)
>     qml.CNOT(wires=[0, 1])
>     m_0 = qml.measure(1)
>     qml.cond(m_0, qml.RY)(y, wires=0)
>     return qml.probs(wires=[0])

How can I read the probability value of m_0, which has been measured?

Hi @RX1,

Unfortunately you cannot read the probabilities for wire 1 since it has already been measured.

So what scheme should be taken to obtain the probability of the conditional measurement of m_0? Since it involves a measurement to get its probability value, I am very interested in knowing the probability of m_0 when it is the base state 0. Can snapshot read it please?

Even if wire0 is measured, I would like to know the density matrix when it is measured or the duration of the delayed measurement, how can I do that?


This functionality is not available in PennyLane just yet. Thank you for your input! Our team is working so that it’ll be available in the future. For now, all probabilities and states are calculated at the end of the circuit.