`kosmos.quantum_logic.quantum_state`¶

Classes¶

class QuantumState(*, creation_time: int | None = 0, rho: numpy.ndarray | None = None, fidelity: float | None = 0.0)¶

Representation of a quantum state using a density matrix.

Initialize and validate density matrix and validity of state.

Parameters:

creation_time (int | None) – Timestamp of creation. Defaults to 0.
rho (np.ndarray | None) – Density matrix of a quantum register. Defaults to None.
fidelity (float | None) – Fidelity value of a quantum register. Defaults to 0.0.

Properties

Methods

validate_density_matrix(rho: numpy.ndarray, tolerance: float = 1e-10) → None¶

Verify whether the density matrix represents a quantum state.

Parameters:

rho (np.ndarray) – Density matrix.
tolerance (float) – Tolerance due to inaccurate calculations. Defaults to 1e-10.

fidelity_from_rho(target: QuantumState) → float¶

Compute Uhlmann fidelity between two states.

fidelity_with_target(target_rho: numpy.ndarray) → float¶

Compute fidelity between this state and an ideal target state.

How close is the actual state to the ideal state.

Parameters:: target_rho (np.ndarray) – Density matrix of the ideal target state.
Returns:: Fidelity value between 0 and 1:
Return type:: float