Utilities

lightworks.tomography.utils.choi_from_unitary(unitary: ndarray[Any, dtype[complex128]]) → ndarray[Any, dtype[complex128]]

Calculates the expected choi matrix from a given unitary representation of a process.

Parameters:

unitary (np.ndarray) – The unitary representation of the gate.

Returns:

The calculated choi matrix.

Return type:

np.ndarray

lightworks.tomography.utils.density_from_state(state: list[complex] | ndarray[Any, dtype[complex128]]) → ndarray[Any, dtype[complex128]]

Calculates the expected density matrix from a given state.

Parameters:

state (list | np.ndarray) – The vector representation of the state for which the density matrix should be calculated.

Returns:

The calculated density matrix.

Return type:

np.ndarray

lightworks.tomography.utils.process_fidelity(choi: ndarray[Any, dtype[complex128]], choi_exp: ndarray[Any, dtype[complex128]]) → float

Calculates the fidelity of a process compared to an expected choi matrix.

Parameters:

• choi (np.ndarray) – The calculated choi matrix for the process.

• choi_exp (np.ndarray) – The expected choi matrix.

Returns:

The calculated fidelity value.

Return type:

float

lightworks.tomography.utils.state_fidelity(rho: ndarray[Any, dtype[complex128]], rho_exp: ndarray[Any, dtype[complex128]]) → float

Calculates the fidelity of the density matrix for a quantum state against the expected density matrix.

Parameters:

• rho (np.ndarray) – The calculated density matrix of the quantum state.

• rho_exp (np.ndarray) – The expected density matrix.

Returns:

The calculated fidelity value.

Return type:

float