QulacsCircuit¶

class QulacsCircuit¶

Qulacs-based quantum circuit implementation.

Wraps QuantumCircuit and Observable from Qulacs to satisfy the circuit protocol interface required by QAOA circuit construction.

Methods

`__init__`
`add_cnot_gate`	Apply a CNOT gate with control qubit i and target qubit j.
`add_h_gate`	Apply a Hadamard gate to qubit i.
`add_observable_rotation_gate`	Apply a Hamiltonian evolution gate `exp(-i * value * H)`.
`add_rx_gate`	Apply an Rx rotation gate to qubit i.
`add_ry_gate`	Apply an Ry rotation gate to qubit i.
`add_x_gate`	Apply a Pauli-X gate to qubit i.
`construct_quantum_circuit`	Create a new Qulacs `QuantumCircuit` with num_qubits qubits.
`get_observable_class`	Return the observable implementation class used by this circuit.

Attributes

`circuit`	Underlying Qulacs `QuantumCircuit` object.
`num_qubits`	Number of qubits in the circuit.

class ObservableImpl¶

Observable builder backed by Observable from Qulacs.

Accumulates Pauli-X and Pauli-Z terms to construct a Hamiltonian used as the generator of a unitary rotation gate.

__init__(num_qubits: int, _obs: Observable | None = None) → None¶

add_pauli_x(num_qubits: int, bit_index: int, value: float) → Self¶

add_pauli_x(num_qubits: int, bit_index: Iterable[int], value: float) → Self

Add a weighted Pauli-X term acting on the specified qubit(s).

Parameters:

num_qubits (int) – Total number of qubits in the operator (unused for Qulacs).
bit_index (int | Iterable[int]) – Qubit index or indices for the X operator.
value (float) – Coefficient of the term.

Returns:

This instance, for chaining.

Return type:

Self

add_pauli_z(num_qubits: int, bit_index: int, value: float) → Self¶

add_pauli_z(num_qubits: int, bit_index: Iterable[int], value: float) → Self

Add a weighted Pauli-Z term acting on the specified qubit(s).

Parameters:

num_qubits (int) – Total number of qubits in the operator (unused for Qulacs).
bit_index (int | Iterable[int]) – Qubit index or indices for the Z operator.
value (float) – Coefficient of the term.

Returns:

This instance, for chaining.

Return type:

Self

static construct_observable(num_qubits: int) → Observable¶

Return an empty Observable over num_qubits qubits.

Parameters:: num_qubits (int) – Number of qubits in the observable.
Returns:: An empty Qulacs Observable over num_qubits qubits.
Return type:: Observable

get_raw() → Observable¶: Return the underlying Qulacs Observable.

T_circuit¶: alias of QuantumCircuit

T_obs¶: alias of Observable

__init__(num_qubits: int) → None¶

add_cnot_gate(i: int, j: int) → Self¶

Apply a CNOT gate with control qubit i and target qubit j.

Parameters:

i (int) – Control qubit index.
j (int) – Target qubit index.

Returns:

This instance, for chaining.

Return type:

Self

add_h_gate(i: int) → Self¶

Apply a Hadamard gate to qubit i.

Parameters:: i (int) – Target qubit index.
Returns:: This instance, for chaining.
Return type:: Self

add_observable_rotation_gate(op_f: SupportsHam[QulacsCircuit.T_obs], value: float, num_qubits: int) → Self¶

Apply a Hamiltonian evolution gate exp(-i * value * H).

Parameters:

op_f (SupportsHam[Observable]) – Observable whose raw Observable is used as the Hamiltonian H.
value (float) – Evolution time (rotation angle).
num_qubits (int) – Number of qubits the gate acts on (unused for Qulacs).

Returns:

This instance, for chaining.

Return type:

Self

add_rx_gate(i: int, value: float) → Self¶

Apply an Rx rotation gate to qubit i.

Parameters:

i (int) – Target qubit index.
value (float) – Rotation angle in radians.

Returns:

This instance, for chaining.

Return type:

Self

add_ry_gate(i: int, value: float) → Self¶

Apply an Ry rotation gate to qubit i.

Parameters:

i (int) – Target qubit index.
value (float) – Rotation angle in radians.

Returns:

This instance, for chaining.

Return type:

Self

add_x_gate(i: int) → Self¶

Apply a Pauli-X gate to qubit i.

Parameters:: i (int) – Target qubit index.
Returns:: This instance, for chaining.
Return type:: Self

static construct_quantum_circuit(num_qubits: int) → QuantumCircuit¶

Create a new Qulacs QuantumCircuit with num_qubits qubits.

Parameters:: num_qubits (int) – Number of qubits.
Returns:: An empty Qulacs QuantumCircuit over num_qubits qubits.
Return type:: QuantumCircuit

classmethod get_observable_class() → type[ObservableImpl]¶: Return the observable implementation class used by this circuit.

property circuit: QuantumCircuit¶: Underlying Qulacs QuantumCircuit object.

property num_qubits: int¶: Number of qubits in the circuit.