def state_transfer_infid(ideal: np.ndarray, actual: tf.constant, index, dims,
psi_0):
"""
Single gate state transfer infidelity. The dimensions of psi_0 and ideal need to be
compatible and index and dims need to project actual to these same dimensions.
Parameters
----------
ideal: np.ndarray
Contains ideal unitary representations of the gate
actual: tf.Tensor
Contains actual unitary representations of the gate
index : int
Index of the qubit(s) in the Hilbert space to be evaluated
dims : list
List of dimensions of qubits
psi_0: tf.Tensor
Initial state
Returns
-------
tf.float
State infidelity for the selected gate
"""
actual_comp = tf_project_to_comp(actual, dims=dims, index=index)
psi_ideal = tf.matmul(ideal, psi_0)
psi_actual = tf.matmul(actual_comp, psi_0)
overlap = tf_ketket_fid(psi_ideal, psi_actual)
infid = 1 - overlap
return infid
def iswap_leakage(U_dict: dict, index, dims, eval, proj=True):
indeces = np.append(
np.append(np.arange(2, dims[1]), np.arange(2, dims[1]) + dims[2]),
np.arange(dims[1] * dims[2], np.prod(dims)),
)
psi_init = [0] * np.prod(dims)
psi_init[1] = 1
psi_0 = tf.Variable(psi_init, dtype=tf.complex128, shape=[np.prod(dims), 1])
psi_actual = tf.matmul(U_dict["Id:iSWAP"], psi_0)
leakage = 0
for indx in indeces: # fix indeces
psi = [0] * np.prod(dims)
psi[indx] = 1
psi = tf.Variable(psi, dtype=tf.complex128, shape=[np.prod(dims), 1])
leakage = leakage + tf_ketket_fid(psi, psi_actual)
return leakage
def state_transfer_infid(U_dict: dict, gate: str, index, dims, psi_0, proj: bool):
"""
Single gate state transfer infidelity.
Parameters
----------
U_dict : dict
Contains unitary representations of the gates, identified by a key.
index : int
Index of the qubit(s) in the Hilbert space to be evaluated
gate : str
One of the keys of U_dict, selects the gate to be evaluated
dims : list
List of dimensions of qubits
psi_0 : tf.Tensor
Initial state of the device
proj : boolean
Project to computational subspace
Returns
-------
tf.float
State infidelity for the selected gate
"""
U = U_dict[gate]
projection = 'fulluni'
if proj:
projection = 'wzeros'
U_ideal = tf.constant(
perfect_gate(gate, index, dims, projection),
dtype=tf.complex128
)
psi_ideal = tf.matmul(U_ideal, psi_0)
psi_actual = tf.matmul(U, psi_0)
overlap = tf_ketket_fid(psi_ideal, psi_actual)
infid = 1 - overlap
return infid