scqubits.Cos2PhiQubit.phi_operator

Cos2PhiQubit.phi_operator(energy_esys=False)

Returns the \(\phi\) operator in the native or eigenenergy basis.

Parameters:

energy_esys (Union[bool, Tuple[ndarray, ndarray]]) – If False (default), returns \(\phi\) operator in the native basis. If True, the energy eigenspectrum is computed, returns \(\phi\) operator in the energy eigenbasis. If energy_esys = esys, where esys is a tuple containing two ndarrays (eigenvalues and energy eigenvectors), returns \(\phi\) operator in the energy eigenbasis, and does not have to recalculate eigenspectrum.

Return type:

Union[ndarray, csc_matrix]

Returns:

\(\phi\) operator in chosen basis. If native basis chosen, operator returned as a csc_matrix. If the eigenenergy basis is chosen, unless energy_esys is specified, \(\phi\) operator has dimensions of truncated_dim x truncated_dim, and is returned as an ndarray. Otherwise, if eigenenergy basis is chosen, \(\phi\) operator has dimensions of m x m, for m given eigenvectors, and is returned as an ndarray.