dq.ground

ground() -> Array

Returns the eigenvector with eigenvalue -1 of the Pauli \(\sigma_z\) operator.

It is defined by \(\ket{g} = \begin{pmatrix}0\\1\end{pmatrix}\).

Note

This function is named ground because \(\ket{g}\) is the lower energy state of a two-level system with Hamiltonian \(H=\omega \sigma_z\).

Returns

(array of shape (2, 1)) Ket \(\ket{g}\).

Examples

>>> dq.ground()
Array([[0.+0.j],
       [1.+0.j]], dtype=complex64)