tqec.circuit.operations.operation.Observable

class Observable(measurement_data: Sequence[Measurement], observable_index: int = 0)[source]

__init__(measurement_data: Sequence[Measurement], observable_index: int = 0) → None[source]

Operation representing an observable.

Since the operation is not a real quantum operation, it does not have qubits and is not applied to any qubits. This might cause surprising behavior if you try to append or insert it into a circuit. It is always recommended to containerize this operation in a cirq.Moment before appending it to a circuit.

In tqec, this kind of annotation operation should be tagged with the cirq.VirtualTag and the STIM_TAG to work correctly with the circuit transformation and the noise model. You can use the make_observable helper function to create an instance of this class with the correct tags. Otherwise, you might need to manually tag the operation with the cirq.VirtualTag and the STIM_TAG.

Warning

you should use make_observable to create instances of this class. To understand how to use this class directly, please refer to the documentation above.

Parameters:

measurement_data – a sequence of Measurement that form a group. There should be no duplicate in the provided sequence.
observable_index – index of the observable.

Methods

`__init__`(measurement_data[, observable_index])	Operation representing an observable.
`controlled_by`(*control_qubits[, control_values])	Returns a controlled version of this operation. If no control_qubits
`transform_qubits`(qubit_map)	Returns the same operation, but with different qubits.
`validate_args`(qubits)	Raises an exception if the qubits don't match this operation's qid shape.
`with_classical_controls`(*conditions)	Returns a classically controlled version of this operation.
`with_probability`(probability)	Creates a probabilistic channel with this operation.
`with_qubits`(*new_qubits)	Returns the same operation, but applied to different qubits.
`with_tags`(*new_tags)	Creates a new TaggedOperation, with this op and the specified tags.
`without_classical_controls`()	Removes all classical controls from the operation.

Attributes

`classical_controls`	The classical controls gating this operation.
`gate`
`index`	Return the index of the observable.
`measurement_data`	The recorded relative measurement data.
`qubits`
`tags`	Returns a tuple of the operation's tags.
`untagged`	Returns the underlying operation without any tags.