Skip to main contentIBM Quantum Documentation
You are viewing the API reference for an old version of Qiskit SDK. Switch to latest version

Quantum Information



Operator(data[, input_dims, output_dims])Matrix operator class
Pauli([data, x, z, label])N-qubit Pauli operator.
Clifford(data[, validate, copy])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.
CNOTDihedral([data, num_qubits, validate])An N-qubit operator from the CNOT-Dihedral group.
PauliList(data)List of N-qubit Pauli operators.
PauliTable(data)Symplectic representation of a list Pauli matrices.
StabilizerTable(data[, phase])Symplectic representation of a list Stabilizer matrices.
pauli_basis(num_qubits[, weight, pauli_list])Return the ordered PauliTable or PauliList for the n-qubit Pauli basis.


Statevector(data[, dims])Statevector class
DensityMatrix(data[, dims])DensityMatrix class
StabilizerState(data[, validate])StabilizerState 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.
concurrence(state)Calculate the concurrence of a quantum state.
entropy(state[, base])Calculate the von-Neumann entropy of a quantum state.
entanglement_of_formation(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_pauli(num_qubits[, group_phase, seed])Return a random Pauli.
random_clifford(num_qubits[, seed])Return a random Clifford operator.
random_quantum_channel([input_dims, ...])Return a random CPTP quantum channel.
random_cnotdihedral(num_qubits[, seed])Return a random CNOTDihedral element.
random_pauli_table(num_qubits[, size, seed])Return a random PauliTable.
random_pauli_list(num_qubits[, size, seed, ...])Return a random PauliList.
random_stabilizer_table(num_qubits[, size, seed])DEPRECATED: Return a random StabilizerTable.


hellinger_distance(dist_p, dist_q)Computes the Hellinger distance between two counts distributions.
hellinger_fidelity(dist_p, dist_q)Computes the Hellinger fidelity between two counts distributions.


OneQubitEulerDecomposer([basis, use_dag])A class for decomposing 1-qubit unitaries into Euler angle rotations.
TwoQubitBasisDecomposer(gate[, ...])A class for decomposing 2-qubit unitaries into minimal number of uses of a 2-qubit basis gate.
Quaternion(data)A class representing a Quaternion.
decompose_clifford(clifford[, method])DEPRECATED: Decompose a Clifford operator into a QuantumCircuit.
XXDecomposer([euler_basis, embodiments, ...])A class for optimal decomposition of 2-qubit unitaries into 2-qubit basis gates of XX type (i.e., each locally equivalent to CAN(alpha, 0, 0) for a possibly varying alpha).
Was this page helpful?
Report a bug or request content on GitHub.