def covariance_mtx_to_superop(self, mtx):
        """
        Converts a covariance matrix to the corresponding
        superoperator, represented as a QuTiP Qobj
        with ``type="super"``.
        """
        M = self.flat()
        return qt.Qobj(
            np.dot(np.dot(M.conj().T, mtx), M),
            dims=[[self.dims] * 2] * 2
        )
Converts a covariance matrix to the corresponding
        superoperator, represented as a QuTiP Qobj
        with ``type="super"``.