Quantum Information (qiskit.quantum_info)


Operator(data[, input_dims, output_dims])

Matrix operator class

Clifford(data[, validate])

An N-qubit unitary operator from the Clifford group.

ScalarOp(dims[, coeff])

Scalar identity operator class.

SparsePauliOp(data[, coeffs])

Sparse N-qubit operator in a Pauli basis representation.

Pauli([z, x, label])

A simple class representing Pauli Operators.

pauli_group(number_of_qubits[, case])

Return the Pauli group with 4^n elements.


A class representing a Quaternion.


Symplectic representation of a list Pauli matrices.

StabilizerTable(data[, phase])

Symplectic representation of a list Stabilizer matrices.

pauli_basis(num_qubits[, weight])

Return the ordered PauliTable for the n-qubit Pauli basis.


Statevector(data[, dims])

Statevector class

DensityMatrix(data[, dims])

DensityMatrix class


Choi(data[, input_dims, output_dims])

Choi-matrix representation of a Quantum Channel.

SuperOp(data[, input_dims, output_dims])

Superoperator representation of a quantum channel.

Kraus(data[, input_dims, output_dims])

Kraus representation of a quantum channel.

Stinespring(data[, input_dims, output_dims])

Stinespring representation of a quantum channel.

Chi(data[, input_dims, output_dims])

Pauli basis Chi-matrix representation of a quantum channel.

PTM(data[, input_dims, output_dims])

Pauli Transfer Matrix (PTM) representation of a Quantum Channel.


average_gate_fidelity(channel[, target, …])

Return the average gate fidelity of a noisy quantum channel.

process_fidelity(channel[, target, …])

Return the process fidelity of a noisy quantum channel.

gate_error(channel[, target, require_cp, …])

Return the gate error of a noisy quantum channel.

diamond_norm(choi, **kwargs)

Return the diamond norm of the input quantum channel object.

state_fidelity(state1, state2[, validate])

Return the state fidelity between two quantum states.

purity(state[, validate])

Calculate the purity of a quantum state.


Calculate the concurrence of a quantum state.

entropy(state[, base])

Calculate the von-Neumann entropy of a quantum state.


Calculate the entanglement of formation of quantum state.

mutual_information(state[, base])

Calculate the mutual information of a bipartite state.

Utility Functions

partial_trace(state, qargs)

Return reduced density matrix by tracing out part of quantum state.

shannon_entropy(pvec[, base])

Compute the Shannon entropy of a probability vector.


random_statevector(dims[, seed])

Generator a random Statevector.

random_density_matrix(dims[, rank, method, seed])

Generator a random DensityMatrix.

random_unitary(dims[, seed])

Return a random unitary Operator.

random_hermitian(dims[, traceless, seed])

Return a random hermitian Operator.

random_clifford(num_qubits[, seed])

Return a random Clifford operator.

random_quantum_channel([input_dims, …])

Return a random CPTP quantum channel.

random_pauli_table(num_qubits[, size, seed])

Return a random PauliTable.

random_stabilizer_table(num_qubits[, size, seed])

Return a random StabilizerTable.

random_state(dim[, seed])

DEPRECATED Return a random quantum state.


hellinger_fidelity(dist_p, dist_q)

Computes the Hellinger fidelity between two counts distributions.



A class for decomposing 1-qubit unitaries into Euler angle rotations.

TwoQubitBasisDecomposer(gate[, basis_fidelity])

A class for decomposing 2-qubit unitaries into minimal number of uses of a 2-qubit basis gate.


A class for decomposing 2-qubit unitaries into minimal number of uses of a 2-qubit basis gate.


DEPRECATED: Compute Euler angles for a single-qubit gate.