# braket.circuits.quantum_operator module¶

class braket.circuits.quantum_operator.QuantumOperator(qubit_count: Optional[int], ascii_symbols: Sequence[str])[source]

A quantum operator is the definition of a quantum operation for a quantum device.

Parameters: qubit_count (Optional[int]) – Number of qubits this quantum operator acts on. If all instances of the operator act on the same number of qubits, this argument should be None, and fixed_qubit_count should be implemented to return the qubit count; if fixed_qubit_count is implemented and an int is passed in, it must equal fixed_qubit_count, or instantiation will raise a ValueError. An int must be passed in if instances can have a varying number of qubits, in which case fixed_qubit_count should not be implemented, ascii_symbols (Sequence[str]) – ASCII string symbols for the quantum operator. These are used when printing a diagram of circuits. Length must be the same as qubit_count, and index ordering is expected to correlate with target ordering on the instruction. For instance, if CNOT instruction has the control qubit on the first index and target qubit on the second index. Then ASCII symbols would have [“C”, “X”] to correlate a symbol with that index. TypeError – qubit_count is not an int ValueError – qubit_count is less than 1, ascii_symbols are None, fixed_qubit_count is implemented and and not equal to qubit_count, or len(ascii_symbols) != qubit_count
static fixed_qubit_count() → int[source]

Returns the number of qubits this quantum operator acts on, if instances are guaranteed to act on the same number of qubits.

If different instances can act on a different number of qubits, this method returns NotImplemented.

Returns: int – The number of qubits this quantum operator acts on.
qubit_count

The number of qubits this quantum operator acts on.

Type: int
ascii_symbols

Returns the ascii symbols for the quantum operator.

Type: Tuple[str, ..]
name

Returns the name of the quantum operator

Returns: str – The name of the quantum operator as a string
to_ir(*args, **kwargs) → Any[source]

Returns IR representation of quantum operator.

Returns: Any – The the canonical intermediate representation of the operator.
to_matrix(*args, **kwargs) → numpy.ndarray[source]

Returns a matrix representation of the quantum operator

Returns: ndarray – A matrix representation of the quantum operator
matrix_equivalence(other: braket.circuits.quantum_operator.QuantumOperator) → bool[source]

Whether the matrix form of two quantum operators are equivalent

Parameters: other (QuantumOperator) – Quantum operator instance to compare this quantum operator to bool – If matrix forms of this quantum operator and the other quantum operator are equivalent