qiskit.quantum_info.DensityMatrix.from_label

classmethod DensityMatrix.from_label(label)

Return a tensor product of Pauli X,Y,Z eigenstates.

Table 18 Single-qubit state labels

Label	Statevector
"0"	$\begin{pmatrix} 1 & 0 \\ 0 & 0 \end{pmatrix}$
"1"	$\begin{pmatrix} 0 & 0 \\ 0 & 1 \end{pmatrix}$
"+"	$\frac{1}{2}\begin{pmatrix} 1 & 1 \\ 1 & 1 \end{pmatrix}$
"-"	$\frac{1}{2}\begin{pmatrix} 1 & -1 \\ -1 & 1 \end{pmatrix}$
"r"	$\frac{1}{2}\begin{pmatrix} 1 & -i \\ i & 1 \end{pmatrix}$
"l"	$\frac{1}{2}\begin{pmatrix} 1 & i \\ -i & 1 \end{pmatrix}$

Parameters

label (string) – a eigenstate string ket label (see table for allowed values).

Returns

The N-qubit basis state density matrix.

Return type

Statevector

Raises

QiskitError – if the label contains invalid characters, or the length of the label is larger than an explicitly specified num_qubits.