qrisp.QuantumCircuit.measure#

QuantumCircuit.measure(qubits: QubitLike, clbits: ClbitLike | None = None) → None[source]#

Append a measurement instruction to the circuit.

For each qubit in qubits a Measurement operation is added that stores the binary outcome in the corresponding entry of clbits. When clbits is omitted the required classical bits are allocated automatically.

Parameters:

qubitsQubitLike: The qubit(s) to measure. A single Qubit object or integer index measures one qubit; any sequence (list, tuple, range, QuantumVariable, …) measures each element independently.
clbitsClbitLike or None, optional: The classical bit(s) that receive the measurement results. When None (default), fresh classical bits are created automatically (one per qubit being measured).

Examples

In this example, we measure a single qubit. One classical bit is allocated automatically:

>>> from qrisp import QuantumCircuit
>>> qc = QuantumCircuit(1)
>>> qc.x(0)
>>> qc.measure(0)
>>> len(qc.clbits)
1

Now we measure several qubits at once. One classical bit is created per qubit:

>>> qc = QuantumCircuit(3)
>>> qc.measure([0, 1, 2])
>>> len(qc.clbits)
3

Finally, we provide explicit classical bits to control where results are stored:

>>> qc = QuantumCircuit(2)
>>> cb0, cb1 = qc.add_clbit(), qc.add_clbit()
>>> qc.measure(0, cb0)
>>> qc.measure(1, cb1)
>>> qc.clbits == [cb0, cb1]
True