cirq.experiments.StateTomographyExperiment

Experiment to conduct state tomography.

Main aliases

cirq.experiments.StateTomographyExperiment(
    qubits: Sequence['cirq.Qid'],
    prerotations: Optional[Sequence[Tuple[float, float]]] = None
)

Generates data collection protocol for the state tomography experiment. Does the fitting of generated data to determine the density matrix.

Args
`qubits`	Qubits to do the tomography on.
`prerotations`	Tuples of (phase_exponent, exponent) parameters for gates to apply to the qubits before measurement. The actual rotation applied will be `cirq.PhasedXPowGate` with the specified values of phase_exponent and exponent. If None, we use [(0, 0), (0, 0.5), (0.5, 0.5)], which corresponds to rotation gates [I, X0.5, Y0.5].

Attributes
`rot_circuit`	Circuit with parameterized rotation gates to do before the final measurements.
`rot_sweep`	The list of rotations on the qubits to perform before measurement.
`mat`	Matrix of coefficients for the system. Each row is one equation corresponding to a rotation sequence and bit string outcome for that rotation sequence. Each column corresponds to the coefficient on one term in the density matrix.
`num_qubits`	Number of qubits to do tomography on.

Methods

fit_density_matrix(
    counts: np.ndarray
) -> cirq.experiments.TomographyResult

Solves equation mat * rho = probs.

Args
`counts`	A 2D array where each row contains measured counts of all n-qubit bitstrings for the corresponding pre-rotations in `rot_sweep`. The order of the probabilities corresponds to to `rot_sweep` and the order of the bit strings corresponds to increasing integers up to 2**(num_qubits)-1.

Returns
`TomographyResult` with density matrix corresponding to solution of this system.