scqubits.TunableTransmon.n_operator

TunableTransmon.n_operator(energy_esys=False)

Returns charge operator n in the charge or eigenenergy basis.

Parameters:

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

Return type:

ndarray

Returns:

Charge operator n in chosen basis as ndarray. For energy_esys=True, n has dimensions of truncated_dim x truncated_dim. If an actual eigensystem is handed to energy_sys, then n has dimensions of m x m, where m is the number of given eigenvectors.