Cell Class

class cell.QuantumCircuitCell

Bases: object

A class to represent a quantum circuit cell, with options for single-qubit gates, controlled gates, and swap gates, measurments.

The gate can be specified as a single qubit gate (e.g., I, X, Y, Z, H, SWAP,M), a controlled qubit gate, or a swap gate, allowing for versatile operations on qubits in a quantum system.

Example

>>> gate = QuantumCircuitCell()
>>> gate.set_controlled_qubit_gate(1, 2, "P", np.pi/2)
>>> gate.print_matrix()
>>> print(gate.get_control_index())
>>> print(gate.get_target_index())
>>> print(gate.is_control_gate())
Output:
[ 1.00 0.00 ]
[ 0.00 0.00+1.00j ]
1
2
True

apply_conditional_gate() → None: This method updates the gate matrix depending on the value of the classical bit connected to this gate. If the classical bit is 1 we keep the matrix of the specified unitary gate otherwise the gate will not be applied and will act as if a identity gate.

apply_matrix(qubit: Qubit) → Qubit

Apply the gate matrix to a qubit and return the resulting qubit.

Parameters:: qubit (Qubit) – The input qubit to which the gate matrix is applied.
Returns:: The resulting qubit after applying the gate.
Return type:: Qubit

conditional_gate_input(classical_bit: int, gate_type: str, phi: float = 0.0) → None

This method recieves an input classical bit. If the input bit is one we apply the desired unitary operation otherwise we don’t won’t to change the qubit state applying the identity matrix.

Parameters:

classical_bit (int) – The input classical bit.
gate_type (str) – The desired unitary opertion gate type.

get_control_index() → int

Return the control qubit index if this gate is a control or swap gate.

Returns:: The index of the control qubit.
Return type:: int
Raises:: ValueError – If the gate is not a control or swap gate.

get_gate_type() → str: This function returns the gate type of this gate (e.g., I, X, Y, Z, H, SWAP) :return: The gate type :rtype: str

get_matrix() → ndarray[Any, dtype[complex128]]

Return the matrix representation of the gate.

Returns:: matrix – The matrix of the current get.
Return type:: NDArray[np.complex128]

get_target_index() → int

Return the target qubit index if this gate is a control or swap gate.

Returns:: The index of the target qubit.
Return type:: int
Raises:: ValueError – If the gate is not a control or swap gate.

is_classical_bit() → bool

Check if this cell represents a classical bit.

Returns:: return_val – True if the cell is a classical bit, False otherwise.
Return type:: bool

is_conditional_gate() → bool

This methods returns a boolean value if the gate is a conditional gate or not.

A conditional gate is a gate that acts on one qubits with an unitary operation if the classical bit input is one. Other wise the gate is just an identity gate.

Returns:: return_val – True if the gate is a measure gate and false otherwiss.
Return type:: bool

is_control_gate() → bool

Returns true or false if the gate is a control gate.

Returns:: Boolean value if the gate is a control gate or not.
Return type:: Bool

is_measure_gate() → bool

This methods returns a boolean value if the gate is a measure gate or not.

Returns:: return_val – True if the gate is a measure gate and false otherwiss.
Return type:: bool

is_single_qubit_gate() → bool

This method returns if the gate is a single qubit gate or not.

Returns:: Returns boolean value if the gate is a single qubit gate.
Return type:: bool

is_swap_gate() → bool

Returns true or false if the gate is a swap gate.

Returns:: Boolean value if the gate is a swap gate or not.
Return type:: Bool

measure(input_state: MultiQubit) → MultiQubit

The method performs a measurment on the current qubit and saves the collapsed state in the classical register specified in measure gate initialization

Parameters:: input_state (MultiQubit) – The input quantum state on which the measurement will be performed.
Returns:: The multi qubit quantum state of the whole system. We expect the non measured qubits to be intact.
Return type:: MultiQubit
Raises:: ValueError – If the current gate is not a measurement gate.

print_matrix() → None

Print the gate matrix with formatted complex values.

Values close to zero are rounded to zero for better readability.

set_classical_bit() → None: Set this cell to represent a classical bit.

set_conditional_gate(gate_type: str, phi: float, c_reg: ClassicalRegister, c_reg_index: int) → None

This method sets this gate to be a a conditional gate.

A conditional gate is a gate that acts on one qubit with an unitary operation if the classical bit is one in the specified classical register. Otherwise the gate will act as an ordinary identity gate.

Parameters:

c_reg (ClassicalRegister) – The classical register object to which the classical bit will be stored.
c_reg_int (int) – The index corresponding to the exact classical bit index in the classical register.

set_controlled_qubit_gate(control_qubit: int, target_qubit: int, gate_type: str = 'I', phi: float = 0.0) → None

Set up a controlled gate with the specified control and target qubits and gate type.

Parameters:

control_qubit (int) – Index of the control qubit.
target_qubit (int) – Index of the target qubit.
gate_type (str) – Type of the gate, should be one of (‘I’, ‘X’, ‘Y’, ‘Z’, ‘H’, ‘P’).
phi (float) – Rotation angle in radians, used only if gate_type is ‘P’ (phase gate).

Raises:

ValueError – If indices are negative or if the gate type is invalid.

set_measure_gate(target_qubit: int, c_reg: ClassicalRegister, c_reg_index: int) → None

The method sets this gate to be a measurement gate.

Parameters:

target_qubit (int) – The qubit index on which the measurement is performed.
c_reg (ClassicalRegister) – The classical register object to which the classical bit will be stored.
c_reg_int (int) – The index corresponding to the exact classical bit index in the classical register.

Raises:

ValueError – If the provided bit index is invalid. Should be between 0 and number of classical bit in the register

set_single_qubit_gate(gate_type: str = 'I', phi: float = 0.0) → None

Set the gate matrix for a specified single qubit gate type or phase gate.

Parameters:

gate_type (str) – Type of the gate, should be one of (‘I’, ‘X’, ‘Y’, ‘Z’, ‘H’, ‘P’).
phi (float) – Rotation angle in radians, used only if gate_type is ‘P’ (phase gate).

Raises:

ValueError – If the gate type is invalid.

set_swap_gate(first_qubit: int, second_qubit: int) → None

Configure a swap gate with the specified first and second qubits.

Parameters:

first_qubit (int) – Index of the first qubit to swap with.
second_qubit (int) – Index of the second qubit to swap with.

Raises:

ValueError – If indices are negative.